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-rw-r--r--nixos/doc/manual/administration/boot-problems.xml4
-rw-r--r--nixos/doc/manual/administration/imperative-containers.xml2
-rw-r--r--nixos/doc/manual/configuration/configuration.xml1
-rw-r--r--nixos/doc/manual/configuration/file-systems.xml8
-rw-r--r--nixos/doc/manual/configuration/gpu-accel.xml263
-rw-r--r--nixos/doc/manual/configuration/ipv4-config.xml2
-rw-r--r--nixos/doc/manual/configuration/ipv6-config.xml2
-rw-r--r--nixos/doc/manual/configuration/luks-file-systems.xml6
-rw-r--r--nixos/doc/manual/configuration/network-manager.xml2
-rw-r--r--nixos/doc/manual/configuration/profiles/demo.xml3
-rw-r--r--nixos/doc/manual/configuration/ssh.xml2
-rw-r--r--nixos/doc/manual/configuration/user-mgmt.xml12
-rw-r--r--nixos/doc/manual/configuration/x-windows.xml46
-rw-r--r--nixos/doc/manual/development/freeform-modules.xml68
-rw-r--r--nixos/doc/manual/development/option-types.xml79
-rwxr-xr-xnixos/doc/manual/development/releases.xml265
-rw-r--r--nixos/doc/manual/development/running-nixos-tests-interactively.xml9
-rw-r--r--nixos/doc/manual/development/settings-options.xml216
-rw-r--r--nixos/doc/manual/development/writing-modules.xml2
-rw-r--r--nixos/doc/manual/development/writing-nixos-tests.xml22
-rw-r--r--nixos/doc/manual/installation/changing-config.xml2
-rw-r--r--nixos/doc/manual/installation/installing-from-other-distro.xml2
-rw-r--r--nixos/doc/manual/installation/installing-pxe.xml2
-rw-r--r--nixos/doc/manual/installation/installing-virtualbox-guest.xml2
-rw-r--r--nixos/doc/manual/installation/installing.xml18
-rw-r--r--nixos/doc/manual/man-nixos-build-vms.xml6
-rw-r--r--nixos/doc/manual/man-nixos-enter.xml12
-rw-r--r--nixos/doc/manual/man-nixos-install.xml16
-rw-r--r--nixos/doc/manual/man-nixos-rebuild.xml4
-rw-r--r--nixos/doc/manual/release-notes/release-notes.xml1
-rw-r--r--nixos/doc/manual/release-notes/rl-2003.xml4
-rw-r--r--nixos/doc/manual/release-notes/rl-2009.xml527
-rw-r--r--nixos/doc/manual/release-notes/rl-2103.xml80
-rw-r--r--nixos/lib/build-vms.nix8
-rw-r--r--nixos/lib/eval-config.nix4
-rw-r--r--nixos/lib/make-disk-image.nix82
-rw-r--r--nixos/lib/make-ext4-fs.nix42
-rw-r--r--nixos/lib/make-iso9660-image.nix4
-rw-r--r--nixos/lib/make-iso9660-image.sh14
-rw-r--r--nixos/lib/make-options-doc/default.nix6
-rw-r--r--nixos/lib/make-options-doc/options-to-docbook.xsl2
-rw-r--r--nixos/lib/qemu-flags.nix15
-rw-r--r--nixos/lib/test-driver/Logger.pm75
-rw-r--r--nixos/lib/test-driver/Machine.pm734
-rw-r--r--nixos/lib/test-driver/test-driver.pl191
-rw-r--r--nixos/lib/test-driver/test-driver.py68
-rw-r--r--nixos/lib/testing-python.nix15
-rw-r--r--nixos/lib/testing.nix258
-rw-r--r--nixos/lib/utils.nix8
-rw-r--r--nixos/maintainers/scripts/azure-new/.gitignore2
-rw-r--r--nixos/maintainers/scripts/azure-new/README.md2
-rwxr-xr-xnixos/maintainers/scripts/azure-new/upload-image.sh4
-rw-r--r--nixos/maintainers/scripts/ec2/amazon-image.nix4
-rwxr-xr-xnixos/maintainers/scripts/ec2/create-amis.sh2
-rw-r--r--nixos/modules/config/appstream.nix8
-rw-r--r--nixos/modules/config/fonts/fontconfig-penultimate.nix292
-rw-r--r--nixos/modules/config/fonts/fontconfig.nix101
-rw-r--r--nixos/modules/config/krb5/default.nix34
-rw-r--r--nixos/modules/config/no-x-libs.nix2
-rw-r--r--nixos/modules/config/system-path.nix28
-rw-r--r--nixos/modules/config/update-users-groups.pl55
-rw-r--r--nixos/modules/config/users-groups.nix97
-rw-r--r--nixos/modules/hardware/bladeRF.nix2
-rw-r--r--nixos/modules/hardware/ckb-next.nix1
-rw-r--r--nixos/modules/hardware/device-tree.nix175
-rw-r--r--nixos/modules/hardware/logitech.nix94
-rw-r--r--nixos/modules/hardware/onlykey.nix2
-rw-r--r--nixos/modules/hardware/tuxedo-keyboard.nix4
-rw-r--r--nixos/modules/hardware/video/hidpi.nix16
-rw-r--r--nixos/modules/hardware/video/uvcvideo/default.nix2
-rw-r--r--nixos/modules/hardware/xpadneo.nix29
-rw-r--r--nixos/modules/i18n/input-method/ibus.nix2
-rw-r--r--nixos/modules/i18n/input-method/uim.nix2
-rw-r--r--nixos/modules/installer/cd-dvd/installation-cd-graphical-gnome.nix20
-rw-r--r--nixos/modules/installer/cd-dvd/installation-cd-graphical-plasma5.nix4
-rw-r--r--nixos/modules/installer/cd-dvd/iso-image.nix9
-rw-r--r--nixos/modules/installer/cd-dvd/sd-image-aarch64.nix8
-rw-r--r--nixos/modules/installer/cd-dvd/sd-image-armv7l-multiplatform.nix8
-rw-r--r--nixos/modules/installer/cd-dvd/sd-image-raspberrypi.nix8
-rw-r--r--nixos/modules/installer/cd-dvd/sd-image-raspberrypi4.nix7
-rw-r--r--nixos/modules/installer/cd-dvd/sd-image.nix26
-rw-r--r--nixos/modules/installer/cd-dvd/system-tarball-pc-readme.txt2
-rw-r--r--nixos/modules/installer/tools/nix-fallback-paths.nix8
-rw-r--r--nixos/modules/installer/tools/nixos-build-vms/nixos-build-vms.sh2
-rw-r--r--nixos/modules/installer/tools/nixos-enter.sh2
-rw-r--r--nixos/modules/installer/tools/nixos-generate-config.pl5
-rw-r--r--nixos/modules/installer/tools/nixos-install.sh86
-rw-r--r--nixos/modules/installer/tools/nixos-option/nixos-option.cc2
-rw-r--r--nixos/modules/installer/tools/nixos-rebuild.sh29
-rw-r--r--nixos/modules/installer/tools/nixos-version.sh2
-rw-r--r--nixos/modules/installer/tools/tools.nix11
-rw-r--r--nixos/modules/misc/documentation.nix38
-rw-r--r--nixos/modules/misc/ids.nix14
-rw-r--r--nixos/modules/misc/locate.nix2
-rw-r--r--nixos/modules/misc/nixpkgs.nix2
-rw-r--r--nixos/modules/module-list.nix38
-rw-r--r--nixos/modules/profiles/base.nix1
-rw-r--r--nixos/modules/profiles/demo.nix10
-rw-r--r--nixos/modules/profiles/hardened.nix5
-rw-r--r--nixos/modules/profiles/installation-device.nix15
-rw-r--r--nixos/modules/programs/autojump.nix4
-rw-r--r--nixos/modules/programs/ccache.nix2
-rw-r--r--nixos/modules/programs/dconf.nix37
-rw-r--r--nixos/modules/programs/environment.nix1
-rw-r--r--nixos/modules/programs/fish.nix3
-rw-r--r--nixos/modules/programs/freetds.nix4
-rw-r--r--nixos/modules/programs/gnupg.nix3
-rw-r--r--nixos/modules/programs/gpaste.nix2
-rw-r--r--nixos/modules/programs/nm-applet.nix15
-rw-r--r--nixos/modules/programs/qt5ct.nix2
-rw-r--r--nixos/modules/programs/ssh.nix2
-rw-r--r--nixos/modules/programs/steam.nix25
-rw-r--r--nixos/modules/programs/tsm-client.nix4
-rw-r--r--nixos/modules/programs/xss-lock.nix2
-rw-r--r--nixos/modules/programs/zsh/oh-my-zsh.xml2
-rw-r--r--nixos/modules/rename.nix11
-rw-r--r--nixos/modules/security/acme.nix671
-rw-r--r--nixos/modules/security/acme.xml20
-rw-r--r--nixos/modules/security/apparmor.nix6
-rw-r--r--nixos/modules/security/duosec.nix2
-rw-r--r--nixos/modules/security/misc.nix14
-rw-r--r--nixos/modules/security/pam.nix53
-rw-r--r--nixos/modules/security/rngd.nix13
-rw-r--r--nixos/modules/security/systemd-confinement.nix2
-rw-r--r--nixos/modules/security/tpm2.nix1
-rw-r--r--nixos/modules/security/wrappers/default.nix3
-rw-r--r--nixos/modules/services/audio/icecast.nix6
-rw-r--r--nixos/modules/services/audio/mpd.nix31
-rw-r--r--nixos/modules/services/audio/roon-server.nix6
-rw-r--r--nixos/modules/services/audio/snapserver.nix166
-rw-r--r--nixos/modules/services/audio/spotifyd.nix2
-rw-r--r--nixos/modules/services/backup/bacula.nix36
-rw-r--r--nixos/modules/services/backup/borgbackup.xml22
-rw-r--r--nixos/modules/services/backup/restic.nix66
-rw-r--r--nixos/modules/services/backup/zfs-replication.nix2
-rw-r--r--nixos/modules/services/backup/znapzend.nix4
-rw-r--r--nixos/modules/services/cluster/kubernetes/pki.nix5
-rw-r--r--nixos/modules/services/computing/slurm/slurm.nix4
-rw-r--r--nixos/modules/services/computing/torque/mom.nix2
-rw-r--r--nixos/modules/services/computing/torque/server.nix2
-rw-r--r--nixos/modules/services/continuous-integration/buildbot/worker.nix11
-rw-r--r--nixos/modules/services/continuous-integration/gitlab-runner.nix93
-rw-r--r--nixos/modules/services/continuous-integration/hercules-ci-agent/common.nix213
-rw-r--r--nixos/modules/services/continuous-integration/hercules-ci-agent/default.nix86
-rw-r--r--nixos/modules/services/databases/couchdb.nix25
-rw-r--r--nixos/modules/services/databases/mysql.nix260
-rw-r--r--nixos/modules/services/databases/openldap.nix30
-rw-r--r--nixos/modules/services/databases/postgresql.nix143
-rw-r--r--nixos/modules/services/databases/riak-cs.nix2
-rw-r--r--nixos/modules/services/databases/victoriametrics.nix4
-rw-r--r--nixos/modules/services/desktops/deepin/deepin.nix123
-rw-r--r--nixos/modules/services/desktops/espanso.nix25
-rw-r--r--nixos/modules/services/desktops/flatpak.nix1
-rw-r--r--nixos/modules/services/desktops/geoclue2.nix2
-rw-r--r--nixos/modules/services/desktops/malcontent.nix5
-rw-r--r--nixos/modules/services/development/jupyter/default.nix28
-rw-r--r--nixos/modules/services/development/jupyterhub/default.nix190
-rw-r--r--nixos/modules/services/development/lorri.nix13
-rw-r--r--nixos/modules/services/editors/emacs.nix47
-rw-r--r--nixos/modules/services/editors/emacs.xml14
-rw-r--r--nixos/modules/services/games/minetest-server.nix16
-rw-r--r--nixos/modules/services/games/terraria.nix20
-rw-r--r--nixos/modules/services/hardware/fancontrol.nix2
-rw-r--r--nixos/modules/services/hardware/sane_extra_backends/brscan4.nix2
-rw-r--r--nixos/modules/services/hardware/thermald.nix10
-rw-r--r--nixos/modules/services/hardware/thinkfan.nix2
-rw-r--r--nixos/modules/services/hardware/tlp.nix59
-rw-r--r--nixos/modules/services/hardware/trezord.nix4
-rw-r--r--nixos/modules/services/hardware/undervolt.nix25
-rw-r--r--nixos/modules/services/logging/logrotate.nix146
-rw-r--r--nixos/modules/services/logging/logstash.nix6
-rw-r--r--nixos/modules/services/mail/dovecot.nix33
-rw-r--r--nixos/modules/services/mail/mailhog.nix68
-rw-r--r--nixos/modules/services/mail/opendkim.nix30
-rw-r--r--nixos/modules/services/mail/pfix-srsd.nix2
-rw-r--r--nixos/modules/services/mail/postfix.nix90
-rw-r--r--nixos/modules/services/mail/roundcube.nix18
-rw-r--r--nixos/modules/services/misc/beanstalkd.nix10
-rw-r--r--nixos/modules/services/misc/calibre-server.nix49
-rw-r--r--nixos/modules/services/misc/gammu-smsd.nix2
-rw-r--r--nixos/modules/services/misc/gitea.nix144
-rw-r--r--nixos/modules/services/misc/gitlab.nix85
-rw-r--r--nixos/modules/services/misc/gitlab.xml6
-rw-r--r--nixos/modules/services/misc/gitolite.nix33
-rw-r--r--nixos/modules/services/misc/gollum.nix9
-rw-r--r--nixos/modules/services/misc/home-assistant.nix1
-rw-r--r--nixos/modules/services/misc/jellyfin.nix15
-rw-r--r--nixos/modules/services/misc/mathics.nix54
-rw-r--r--nixos/modules/services/misc/matrix-synapse.nix2
-rw-r--r--nixos/modules/services/misc/matrix-synapse.xml38
-rw-r--r--nixos/modules/services/misc/mautrix-telegram.nix2
-rw-r--r--nixos/modules/services/misc/mesos-master.nix125
-rw-r--r--nixos/modules/services/misc/mesos-slave.nix220
-rw-r--r--nixos/modules/services/misc/nix-daemon.nix171
-rw-r--r--nixos/modules/services/misc/octoprint.nix4
-rw-r--r--nixos/modules/services/misc/pinnwand.nix78
-rw-r--r--nixos/modules/services/misc/redmine.nix102
-rw-r--r--nixos/modules/services/misc/siproxd.nix8
-rw-r--r--nixos/modules/services/misc/ssm-agent.nix6
-rw-r--r--nixos/modules/services/misc/sssd.nix4
-rw-r--r--nixos/modules/services/misc/tzupdate.nix4
-rw-r--r--nixos/modules/services/misc/zigbee2mqtt.nix98
-rw-r--r--nixos/modules/services/monitoring/cadvisor.nix2
-rw-r--r--nixos/modules/services/monitoring/datadog-agent.nix14
-rw-r--r--nixos/modules/services/monitoring/dd-agent/dd-agent.nix4
-rw-r--r--nixos/modules/services/monitoring/do-agent.nix17
-rw-r--r--nixos/modules/services/monitoring/monit.nix2
-rw-r--r--nixos/modules/services/monitoring/netdata.nix45
-rw-r--r--nixos/modules/services/monitoring/prometheus/default.nix29
-rw-r--r--nixos/modules/services/monitoring/prometheus/exporters.nix5
-rw-r--r--nixos/modules/services/monitoring/prometheus/exporters/modemmanager.nix33
-rw-r--r--nixos/modules/services/monitoring/prometheus/exporters/unifi-poller.nix34
-rw-r--r--nixos/modules/services/monitoring/smartd.nix18
-rw-r--r--nixos/modules/services/monitoring/teamviewer.nix2
-rw-r--r--nixos/modules/services/monitoring/unifi-poller.nix242
-rw-r--r--nixos/modules/services/monitoring/zabbix-agent.nix41
-rw-r--r--nixos/modules/services/monitoring/zabbix-proxy.nix75
-rw-r--r--nixos/modules/services/monitoring/zabbix-server.nix72
-rw-r--r--nixos/modules/services/network-filesystems/cachefilesd.nix18
-rw-r--r--nixos/modules/services/network-filesystems/ipfs.nix22
-rw-r--r--nixos/modules/services/network-filesystems/orangefs/server.nix4
-rw-r--r--nixos/modules/services/network-filesystems/samba.nix2
-rw-r--r--nixos/modules/services/networking/3proxy.nix2
-rw-r--r--nixos/modules/services/networking/biboumi.nix269
-rw-r--r--nixos/modules/services/networking/bitcoind.nix206
-rw-r--r--nixos/modules/services/networking/blockbook-frontend.nix275
-rw-r--r--nixos/modules/services/networking/corerad.nix3
-rw-r--r--nixos/modules/services/networking/dhcpd.nix12
-rw-r--r--nixos/modules/services/networking/gateone.nix2
-rw-r--r--nixos/modules/services/networking/heyefi.nix82
-rw-r--r--nixos/modules/services/networking/hylafax/options.nix4
-rw-r--r--nixos/modules/services/networking/jicofo.nix152
-rw-r--r--nixos/modules/services/networking/jitsi-videobridge.nix276
-rw-r--r--nixos/modules/services/networking/kresd.nix13
-rw-r--r--nixos/modules/services/networking/monero.nix2
-rw-r--r--nixos/modules/services/networking/mstpd.nix2
-rw-r--r--nixos/modules/services/networking/namecoind.nix2
-rw-r--r--nixos/modules/services/networking/ncdns.nix278
-rw-r--r--nixos/modules/services/networking/networkmanager.nix2
-rw-r--r--nixos/modules/services/networking/nextdns.nix44
-rw-r--r--nixos/modules/services/networking/nghttpx/default.nix6
-rw-r--r--nixos/modules/services/networking/nsd.nix7
-rw-r--r--nixos/modules/services/networking/ntp/chrony.nix1
-rw-r--r--nixos/modules/services/networking/nylon.nix2
-rw-r--r--nixos/modules/services/networking/onedrive.nix72
-rw-r--r--nixos/modules/services/networking/onedrive.xml34
-rw-r--r--nixos/modules/services/networking/openvpn.nix2
-rw-r--r--nixos/modules/services/networking/prosody.nix4
-rw-r--r--nixos/modules/services/networking/prosody.xml13
-rw-r--r--nixos/modules/services/networking/radicale.nix11
-rw-r--r--nixos/modules/services/networking/resilio.nix10
-rw-r--r--nixos/modules/services/networking/robustirc-bridge.nix47
-rw-r--r--nixos/modules/services/networking/seeks.nix75
-rw-r--r--nixos/modules/services/networking/shadowsocks.nix54
-rw-r--r--nixos/modules/services/networking/skydns.nix2
-rw-r--r--nixos/modules/services/networking/ssh/sshd.nix12
-rw-r--r--nixos/modules/services/networking/sslh.nix18
-rw-r--r--nixos/modules/services/networking/supplicant.nix26
-rw-r--r--nixos/modules/services/networking/syncthing.nix13
-rw-r--r--nixos/modules/services/networking/tinc.nix16
-rw-r--r--nixos/modules/services/networking/trickster.nix5
-rw-r--r--nixos/modules/services/networking/unifi.nix2
-rw-r--r--nixos/modules/services/networking/wasabibackend.nix158
-rw-r--r--nixos/modules/services/networking/websockify.nix6
-rw-r--r--nixos/modules/services/networking/wg-quick.nix20
-rw-r--r--nixos/modules/services/networking/wireguard.nix15
-rw-r--r--nixos/modules/services/networking/wpa_supplicant.nix5
-rw-r--r--nixos/modules/services/networking/xandikos.nix4
-rw-r--r--nixos/modules/services/networking/yggdrasil.nix5
-rw-r--r--nixos/modules/services/networking/yggdrasil.xml157
-rw-r--r--nixos/modules/services/scheduling/chronos.nix54
-rw-r--r--nixos/modules/services/scheduling/marathon.nix98
-rw-r--r--nixos/modules/services/security/bitwarden_rs/default.nix19
-rw-r--r--nixos/modules/services/security/haveged.nix18
-rw-r--r--nixos/modules/services/security/nginx-sso.nix11
-rw-r--r--nixos/modules/services/security/oauth2_proxy.nix12
-rw-r--r--nixos/modules/services/security/physlock.nix10
-rw-r--r--nixos/modules/services/security/privacyidea.nix1
-rw-r--r--nixos/modules/services/security/tor.nix24
-rw-r--r--nixos/modules/services/security/usbguard.nix124
-rw-r--r--nixos/modules/services/security/yubikey-agent.nix60
-rw-r--r--nixos/modules/services/system/earlyoom.nix1
-rw-r--r--nixos/modules/services/torrent/transmission.nix451
-rw-r--r--nixos/modules/services/video/epgstation/default.nix295
-rwxr-xr-xnixos/modules/services/video/epgstation/generate31
-rw-r--r--nixos/modules/services/video/epgstation/streaming.json119
-rw-r--r--nixos/modules/services/video/mirakurun.nix183
-rw-r--r--nixos/modules/services/wayland/cage.nix3
-rw-r--r--nixos/modules/services/web-apps/codimd.nix4
-rw-r--r--nixos/modules/services/web-apps/convos.nix72
-rw-r--r--nixos/modules/services/web-apps/dokuwiki.nix28
-rw-r--r--nixos/modules/services/web-apps/gerrit.nix21
-rw-r--r--nixos/modules/services/web-apps/jitsi-meet.nix334
-rw-r--r--nixos/modules/services/web-apps/jitsi-meet.xml55
-rw-r--r--nixos/modules/services/web-apps/moodle.nix14
-rw-r--r--nixos/modules/services/web-apps/nextcloud.nix277
-rw-r--r--nixos/modules/services/web-apps/nextcloud.xml67
-rw-r--r--nixos/modules/services/web-apps/pgpkeyserver-lite.nix2
-rw-r--r--nixos/modules/services/web-apps/rss-bridge.nix127
-rw-r--r--nixos/modules/services/web-apps/sogo.nix1
-rw-r--r--nixos/modules/services/web-apps/trilium.nix2
-rw-r--r--nixos/modules/services/web-apps/tt-rss.nix2
-rw-r--r--nixos/modules/services/web-servers/apache-httpd/default.nix109
-rw-r--r--nixos/modules/services/web-servers/caddy.nix66
-rw-r--r--nixos/modules/services/web-servers/jboss/builder.sh12
-rw-r--r--nixos/modules/services/web-servers/meguca.nix174
-rw-r--r--nixos/modules/services/web-servers/molly-brown.nix117
-rw-r--r--nixos/modules/services/web-servers/nginx/default.nix105
-rw-r--r--nixos/modules/services/web-servers/phpfpm/default.nix1
-rw-r--r--nixos/modules/services/web-servers/shellinabox.nix2
-rw-r--r--nixos/modules/services/web-servers/traefik.nix4
-rw-r--r--nixos/modules/services/web-servers/unit/default.nix5
-rw-r--r--nixos/modules/services/x11/colord.nix2
-rw-r--r--nixos/modules/services/x11/desktop-managers/cinnamon.nix205
-rw-r--r--nixos/modules/services/x11/desktop-managers/default.nix1
-rw-r--r--nixos/modules/services/x11/desktop-managers/pantheon.nix2
-rw-r--r--nixos/modules/services/x11/desktop-managers/plasma5.nix20
-rw-r--r--nixos/modules/services/x11/display-managers/default.nix64
-rw-r--r--nixos/modules/services/x11/display-managers/gdm.nix74
-rw-r--r--nixos/modules/services/x11/display-managers/lightdm-greeters/pantheon.nix2
-rw-r--r--nixos/modules/services/x11/display-managers/lightdm.nix66
-rw-r--r--nixos/modules/services/x11/display-managers/sddm.nix63
-rw-r--r--nixos/modules/services/x11/hardware/libinput.nix1
-rw-r--r--nixos/modules/services/x11/imwheel.nix3
-rw-r--r--nixos/modules/services/x11/urserver.nix38
-rw-r--r--nixos/modules/services/x11/window-managers/qtile.nix2
-rw-r--r--nixos/modules/services/x11/window-managers/xmonad.nix30
-rw-r--r--nixos/modules/services/x11/xserver.nix20
-rw-r--r--nixos/modules/system/activation/top-level.nix19
-rw-r--r--nixos/modules/system/boot/emergency-mode.nix2
-rw-r--r--nixos/modules/system/boot/initrd-network.nix2
-rw-r--r--nixos/modules/system/boot/initrd-openvpn.nix81
-rw-r--r--nixos/modules/system/boot/kernel_config.nix2
-rw-r--r--nixos/modules/system/boot/loader/generations-dir/generations-dir-builder.sh2
-rw-r--r--nixos/modules/system/boot/loader/generic-extlinux-compatible/default.nix29
-rw-r--r--nixos/modules/system/boot/loader/generic-extlinux-compatible/extlinux-conf-builder.sh17
-rw-r--r--nixos/modules/system/boot/loader/grub/grub.nix106
-rw-r--r--nixos/modules/system/boot/loader/grub/install-grub.pl163
-rw-r--r--nixos/modules/system/boot/loader/init-script/init-script-builder.sh2
-rw-r--r--nixos/modules/system/boot/loader/raspberrypi/raspberrypi-builder.nix4
-rw-r--r--nixos/modules/system/boot/loader/raspberrypi/raspberrypi-builder.sh5
-rw-r--r--nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py4
-rw-r--r--nixos/modules/system/boot/loader/systemd-boot/systemd-boot.nix4
-rw-r--r--nixos/modules/system/boot/luksroot.nix38
-rw-r--r--nixos/modules/system/boot/modprobe.nix2
-rw-r--r--nixos/modules/system/boot/networkd.nix1492
-rw-r--r--nixos/modules/system/boot/plymouth.nix3
-rw-r--r--nixos/modules/system/boot/stage-1-init.sh22
-rw-r--r--nixos/modules/system/boot/stage-1.nix30
-rw-r--r--nixos/modules/system/boot/stage-2-init.sh2
-rw-r--r--nixos/modules/system/boot/stage-2.nix10
-rw-r--r--nixos/modules/system/boot/systemd-nspawn.nix6
-rw-r--r--nixos/modules/system/boot/systemd-unit-options.nix11
-rw-r--r--nixos/modules/system/boot/systemd.nix152
-rw-r--r--nixos/modules/system/boot/tmp.nix2
-rw-r--r--nixos/modules/system/etc/etc.nix2
-rw-r--r--nixos/modules/system/etc/make-etc.sh7
-rw-r--r--nixos/modules/tasks/auto-upgrade.nix98
-rw-r--r--nixos/modules/tasks/bcache.nix2
-rw-r--r--nixos/modules/tasks/encrypted-devices.nix21
-rw-r--r--nixos/modules/tasks/filesystems.nix4
-rw-r--r--nixos/modules/tasks/filesystems/zfs.nix51
-rw-r--r--nixos/modules/tasks/lvm.nix67
-rw-r--r--nixos/modules/tasks/network-interfaces-scripted.nix4
-rw-r--r--nixos/modules/tasks/network-interfaces.nix8
-rw-r--r--nixos/modules/testing/test-instrumentation.nix27
-rw-r--r--nixos/modules/virtualisation/azure-image.nix2
-rw-r--r--nixos/modules/virtualisation/containers.nix75
-rw-r--r--nixos/modules/virtualisation/cri-o.nix6
-rw-r--r--nixos/modules/virtualisation/docker-preloader.nix134
-rw-r--r--nixos/modules/virtualisation/docker.nix1
-rw-r--r--nixos/modules/virtualisation/libvirtd.nix4
-rw-r--r--nixos/modules/virtualisation/nixos-containers.nix2
-rw-r--r--nixos/modules/virtualisation/parallels-guest.nix2
-rw-r--r--nixos/modules/virtualisation/podman.nix28
-rw-r--r--nixos/modules/virtualisation/qemu-vm.nix155
-rw-r--r--nixos/modules/virtualisation/railcar.nix16
-rw-r--r--nixos/modules/virtualisation/spice-usb-redirection.nix24
-rw-r--r--nixos/modules/virtualisation/virtualbox-guest.nix2
-rw-r--r--nixos/modules/virtualisation/virtualbox-image.nix66
-rw-r--r--nixos/release-combined.nix18
-rw-r--r--nixos/release.nix5
-rw-r--r--nixos/tests/3proxy.nix4
-rw-r--r--nixos/tests/acme.nix362
-rw-r--r--nixos/tests/all-tests.nix38
-rw-r--r--nixos/tests/bcachefs.nix2
-rw-r--r--nixos/tests/bitcoind.nix46
-rw-r--r--nixos/tests/bittorrent.nix24
-rw-r--r--nixos/tests/bitwarden.nix188
-rw-r--r--nixos/tests/blockbook-frontend.nix28
-rw-r--r--nixos/tests/borgbackup.nix2
-rw-r--r--nixos/tests/caddy.nix18
-rw-r--r--nixos/tests/ceph-multi-node.nix6
-rw-r--r--nixos/tests/ceph-single-node.nix6
-rw-r--r--nixos/tests/charliecloud.nix43
-rw-r--r--nixos/tests/common/acme/client/default.nix11
-rw-r--r--nixos/tests/common/acme/server/default.nix72
-rw-r--r--nixos/tests/common/acme/server/mkcerts.nix68
-rwxr-xr-xnixos/tests/common/acme/server/mkcerts.sh6
-rw-r--r--nixos/tests/common/acme/server/snakeoil-certs.nix206
-rw-r--r--nixos/tests/common/auto.nix4
-rw-r--r--nixos/tests/common/ec2.nix58
-rw-r--r--nixos/tests/consul.nix136
-rw-r--r--nixos/tests/containers-portforward.nix2
-rw-r--r--nixos/tests/containers-reloadable.nix4
-rw-r--r--nixos/tests/convos.nix30
-rw-r--r--nixos/tests/corerad.nix2
-rw-r--r--nixos/tests/couchdb.nix80
-rw-r--r--nixos/tests/cri-o.nix19
-rw-r--r--nixos/tests/docker-preloader.nix27
-rw-r--r--nixos/tests/docker-tools.nix74
-rw-r--r--nixos/tests/docker.nix4
-rw-r--r--nixos/tests/dokuwiki.nix24
-rw-r--r--nixos/tests/ec2.nix140
-rw-r--r--nixos/tests/firejail.nix82
-rw-r--r--nixos/tests/gnome3-xorg.nix6
-rw-r--r--nixos/tests/gnome3.nix16
-rw-r--r--nixos/tests/gotify-server.nix5
-rw-r--r--nixos/tests/graphite.nix11
-rw-r--r--nixos/tests/grub.nix60
-rw-r--r--nixos/tests/hardened.nix114
-rw-r--r--nixos/tests/hocker-fetchdocker/default.nix9
-rw-r--r--nixos/tests/home-assistant.nix132
-rw-r--r--nixos/tests/hydra/common.nix1
-rw-r--r--nixos/tests/ihatemoney.nix13
-rw-r--r--nixos/tests/initrd-network-openvpn/default.nix145
-rw-r--r--nixos/tests/initrd-network-openvpn/initrd.ovpn29
-rw-r--r--nixos/tests/initrd-network-openvpn/shared.key21
-rw-r--r--nixos/tests/installed-tests/default.nix6
-rw-r--r--nixos/tests/installed-tests/flatpak.nix9
-rw-r--r--nixos/tests/installed-tests/ibus.nix14
-rw-r--r--nixos/tests/installed-tests/ostree.nix11
-rw-r--r--nixos/tests/installer.nix35
-rw-r--r--nixos/tests/jitsi-meet.nix55
-rw-r--r--nixos/tests/krb5/example-config.nix8
-rw-r--r--nixos/tests/kubernetes/base.nix1
-rw-r--r--nixos/tests/leaps.nix2
-rw-r--r--nixos/tests/lorri/default.nix2
-rw-r--r--nixos/tests/lxd-nftables.nix1
-rw-r--r--nixos/tests/lxd.nix14
-rw-r--r--nixos/tests/make-test.nix9
-rw-r--r--nixos/tests/mathics.nix20
-rw-r--r--nixos/tests/mesos.nix92
-rw-r--r--nixos/tests/mesos_test.py72
-rw-r--r--nixos/tests/misc.nix32
-rw-r--r--nixos/tests/molly-brown.nix71
-rw-r--r--nixos/tests/mongodb.nix6
-rw-r--r--nixos/tests/mysql/mysql.nix22
-rw-r--r--nixos/tests/ncdns.nix77
-rw-r--r--nixos/tests/networking.nix21
-rw-r--r--nixos/tests/nextcloud/basic.nix9
-rw-r--r--nixos/tests/nextcloud/with-mysql-and-memcached.nix1
-rw-r--r--nixos/tests/nextcloud/with-postgresql-and-redis.nix1
-rw-r--r--nixos/tests/nfs/kerberos.nix4
-rw-r--r--nixos/tests/nginx-sandbox.nix1
-rw-r--r--nixos/tests/nginx-variants.nix33
-rw-r--r--nixos/tests/openstack-image.nix70
-rw-r--r--nixos/tests/os-prober.nix33
-rw-r--r--nixos/tests/pinnwand.nix86
-rw-r--r--nixos/tests/plasma5.nix2
-rw-r--r--nixos/tests/podman.nix3
-rw-r--r--nixos/tests/postfix-raise-smtpd-tls-security-level.nix41
-rw-r--r--nixos/tests/postfix.nix77
-rw-r--r--nixos/tests/postgresql-wal-receiver.nix182
-rw-r--r--nixos/tests/prometheus-exporters.nix58
-rw-r--r--nixos/tests/prometheus.nix7
-rw-r--r--nixos/tests/pt2-clone.nix35
-rw-r--r--nixos/tests/radicale.nix28
-rw-r--r--nixos/tests/restic.nix55
-rw-r--r--nixos/tests/robustirc-bridge.nix29
-rw-r--r--nixos/tests/sddm.nix4
-rw-r--r--nixos/tests/shadowsocks/common.nix84
-rw-r--r--nixos/tests/shadowsocks/default.nix16
-rw-r--r--nixos/tests/shattered-pixel-dungeon.nix29
-rw-r--r--nixos/tests/slurm.nix93
-rw-r--r--nixos/tests/snapcast.nix58
-rw-r--r--nixos/tests/sslh.nix83
-rw-r--r--nixos/tests/sssd-ldap.nix78
-rw-r--r--nixos/tests/sssd.nix17
-rw-r--r--nixos/tests/sudo.nix2
-rw-r--r--nixos/tests/syncthing-init.nix3
-rw-r--r--nixos/tests/syncthing.nix65
-rw-r--r--nixos/tests/systemd-boot.nix32
-rw-r--r--nixos/tests/systemd-networkd-ipv6-prefix-delegation.nix8
-rw-r--r--nixos/tests/systemd-networkd-vrf.nix24
-rw-r--r--nixos/tests/systemd-networkd.nix11
-rw-r--r--nixos/tests/systemd.nix53
-rw-r--r--nixos/tests/taskserver.nix310
-rw-r--r--nixos/tests/tiddlywiki.nix2
-rw-r--r--nixos/tests/transmission.nix2
-rw-r--r--nixos/tests/trezord.nix5
-rw-r--r--nixos/tests/trickster.nix6
-rw-r--r--nixos/tests/v2ray.nix83
-rw-r--r--nixos/tests/virtualbox.nix419
-rw-r--r--nixos/tests/wasabibackend.nix38
-rw-r--r--nixos/tests/xandikos.nix6
-rw-r--r--nixos/tests/xfce.nix4
-rw-r--r--nixos/tests/xmpp/ejabberd.nix16
-rw-r--r--nixos/tests/xmpp/xmpp-sendmessage.nix6
-rw-r--r--nixos/tests/yggdrasil.nix42
-rw-r--r--nixos/tests/zfs.nix23
-rw-r--r--nixos/tests/zigbee2mqtt.nix19
502 files changed, 16444 insertions, 7686 deletions
diff --git a/nixos/doc/manual/administration/boot-problems.xml b/nixos/doc/manual/administration/boot-problems.xml
index badc374ebcfd9..e0f662840101d 100644
--- a/nixos/doc/manual/administration/boot-problems.xml
+++ b/nixos/doc/manual/administration/boot-problems.xml
@@ -58,9 +58,9 @@
       Like <literal>boot.debug1</literal> or
       <literal>boot.debug1devices</literal>, but runs stage1 until all
       filesystems that are mounted during initrd are mounted (see
-      <option><link linkend="opt-fileSystems._name__.neededForBoot">neededForBoot</link></option>
+      <option><link linkend="opt-fileSystems._name_.neededForBoot">neededForBoot</link></option>
       ). As a motivating example, this could be useful if you've forgotten to set
-      <option><link linkend="opt-fileSystems._name__.neededForBoot">neededForBoot</link></option>
+      <option><link linkend="opt-fileSystems._name_.neededForBoot">neededForBoot</link></option>
       on a file system.
      </para>
     </listitem>
diff --git a/nixos/doc/manual/administration/imperative-containers.xml b/nixos/doc/manual/administration/imperative-containers.xml
index 7ded0c11786e1..435ed230f5133 100644
--- a/nixos/doc/manual/administration/imperative-containers.xml
+++ b/nixos/doc/manual/administration/imperative-containers.xml
@@ -27,7 +27,7 @@
 <screen>
 # nixos-container create foo --config '
   <xref linkend="opt-services.openssh.enable"/> = true;
-  <link linkend="opt-users.users._name__.openssh.authorizedKeys.keys">users.users.root.openssh.authorizedKeys.keys</link> = ["ssh-dss AAAAB3N…"];
+  <link linkend="opt-users.users._name_.openssh.authorizedKeys.keys">users.users.root.openssh.authorizedKeys.keys</link> = ["ssh-dss AAAAB3N…"];
 '
 </screen>
   By default the next free address in the <literal>10.233.0.0/16</literal> subnet will be chosen
diff --git a/nixos/doc/manual/configuration/configuration.xml b/nixos/doc/manual/configuration/configuration.xml
index 507d28814ead3..6eb8f50bacac6 100644
--- a/nixos/doc/manual/configuration/configuration.xml
+++ b/nixos/doc/manual/configuration/configuration.xml
@@ -18,6 +18,7 @@
  <xi:include href="user-mgmt.xml" />
  <xi:include href="file-systems.xml" />
  <xi:include href="x-windows.xml" />
+ <xi:include href="gpu-accel.xml" />
  <xi:include href="xfce.xml" />
  <xi:include href="networking.xml" />
  <xi:include href="linux-kernel.xml" />
diff --git a/nixos/doc/manual/configuration/file-systems.xml b/nixos/doc/manual/configuration/file-systems.xml
index 3ac02a975ebf6..9747433375fc5 100644
--- a/nixos/doc/manual/configuration/file-systems.xml
+++ b/nixos/doc/manual/configuration/file-systems.xml
@@ -23,12 +23,12 @@
   <link xlink:href="https://www.freedesktop.org/software/systemd/man/systemd-fstab-generator.html">systemd-fstab-generator</link>.
   The filesystem will be mounted automatically unless
   <literal>"noauto"</literal> is present in <link
-  linkend="opt-fileSystems._name__.options">options</link>.
+  linkend="opt-fileSystems._name_.options">options</link>.
   <literal>"noauto"</literal> filesystems can be mounted explicitly using
   <command>systemctl</command> e.g. <command>systemctl start
   data.mount</command>.
   Mount points are created automatically if they don’t already exist. For
-  <option><link linkend="opt-fileSystems._name__.device">device</link></option>,
+  <option><link linkend="opt-fileSystems._name_.device">device</link></option>,
   it’s best to use the topology-independent device aliases in
   <filename>/dev/disk/by-label</filename> and
   <filename>/dev/disk/by-uuid</filename>, as these don’t change if the
@@ -36,7 +36,7 @@
  </para>
  <para>
   You can usually omit the file system type
-  (<option><link linkend="opt-fileSystems._name__.fsType">fsType</link></option>),
+  (<option><link linkend="opt-fileSystems._name_.fsType">fsType</link></option>),
   since <command>mount</command> can usually detect the type and load the
   necessary kernel module automatically. However, if the file system is needed
   at early boot (in the initial ramdisk) and is not <literal>ext2</literal>,
@@ -49,7 +49,7 @@
    System startup will fail if any of the filesystems fails to mount, dropping
    you to the emergency shell. You can make a mount asynchronous and
    non-critical by adding
-   <literal><link linkend="opt-fileSystems._name__.options">options</link> = [
+   <literal><link linkend="opt-fileSystems._name_.options">options</link> = [
    "nofail" ];</literal>.
   </para>
  </note>
diff --git a/nixos/doc/manual/configuration/gpu-accel.xml b/nixos/doc/manual/configuration/gpu-accel.xml
new file mode 100644
index 0000000000000..95ee13f4796e8
--- /dev/null
+++ b/nixos/doc/manual/configuration/gpu-accel.xml
@@ -0,0 +1,263 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="sec-gpu-accel">
+  <title>GPU acceleration</title>
+
+  <para>
+    NixOS provides various APIs that benefit from GPU hardware
+    acceleration, such as VA-API and VDPAU for video playback; OpenGL and
+    Vulkan for 3D graphics; and OpenCL for general-purpose computing.
+    This chapter describes how to set up GPU hardware acceleration (as far
+    as this is not done automatically) and how to verify that hardware
+    acceleration is indeed used.
+  </para>
+
+  <para>
+    Most of the aforementioned APIs are agnostic with regards to which
+    display server is used. Consequently, these instructions should apply
+    both to the X Window System and Wayland compositors.
+  </para>
+
+  <section xml:id="sec-gpu-accel-opencl">
+    <title>OpenCL</title>
+
+    <para>
+      <link xlink:href="https://en.wikipedia.org/wiki/OpenCL">OpenCL</link> is a
+      general compute API. It is used by various applications such as
+      Blender and Darktable to accelerate certain operations.
+    </para>
+
+    <para>
+      OpenCL applications load drivers through the <emphasis>Installable Client
+      Driver</emphasis> (ICD) mechanism. In this mechanism, an ICD file
+      specifies the path to the OpenCL driver for a particular GPU family.
+      In NixOS, there are two ways to make ICD files visible to the ICD
+      loader. The first is through the <varname>OCL_ICD_VENDORS</varname>
+      environment variable. This variable can contain a directory which
+      is scanned by the ICL loader for ICD files. For example:
+
+      <screen><prompt>$</prompt> export \
+  OCL_ICD_VENDORS=`nix-build '&lt;nixpkgs&gt;' --no-out-link -A rocm-opencl-icd`/etc/OpenCL/vendors/</screen>
+    </para>
+
+    <para>
+      The second mechanism is to add the OpenCL driver package to
+      <xref linkend="opt-hardware.opengl.extraPackages"/>. This links the
+      ICD file under <filename>/run/opengl-driver</filename>, where it will
+      be visible to the ICD loader.
+    </para>
+
+    <para>
+      The proper installation of OpenCL drivers can be verified through
+      the <command>clinfo</command> command of the <package>clinfo</package>
+      package. This command will report the number of hardware devices
+      that is found and give detailed information for each device:
+    </para>
+
+    <screen><prompt>$</prompt> clinfo | head -n3
+Number of platforms  1
+Platform Name        AMD Accelerated Parallel Processing
+Platform Vendor      Advanced Micro Devices, Inc.</screen>
+
+    <section xml:id="sec-gpu-accel-opencl-amd">
+      <title>AMD</title>
+
+      <para>
+	Modern AMD <link
+	xlink:href="https://en.wikipedia.org/wiki/Graphics_Core_Next">Graphics
+	Core Next</link> (GCN) GPUs are supported through the
+	<package>rocm-opencl-icd</package> package. Adding this package to
+	<xref linkend="opt-hardware.opengl.extraPackages"/> enables OpenCL
+	support:
+
+	<programlisting><xref linkend="opt-hardware.opengl.extraPackages"/> = [
+  rocm-opencl-icd
+];</programlisting>
+      </para>
+    </section>
+
+    <section xml:id="sec-gpu-accel-opencl-intel">
+      <title>Intel</title>
+
+      <para>
+       <link
+         xlink:href="https://en.wikipedia.org/wiki/List_of_Intel_graphics_processing_units#Gen8">Intel
+       Gen8 and later GPUs</link> are supported by the Intel NEO OpenCL
+       runtime that is provided by the
+       <package>intel-compute-runtime</package> package. For Gen7 GPUs,
+       the deprecated Beignet runtime can be used, which is provided
+       by the <package>beignet</package> package. The proprietary Intel
+       OpenCL runtime, in the <package>intel-ocl</package> package, is
+       an alternative for Gen7 GPUs.
+      </para>
+
+      <para>
+       The <package>intel-compute-runtime</package>, <package>beignet</package>,
+       or <package>intel-ocl</package> package can be added to
+       <xref linkend="opt-hardware.opengl.extraPackages"/> to enable OpenCL
+       support. For example, for Gen8 and later GPUs, the following
+       configuration can be used:
+
+	      <programlisting><xref linkend="opt-hardware.opengl.extraPackages"/> = [
+  intel-compute-runtime
+];</programlisting>
+
+      </para>
+    </section>
+  </section>
+
+  <section xml:id="sec-gpu-accel-vulkan">
+    <title>Vulkan</title>
+
+    <para>
+      <link xlink:href="https://en.wikipedia.org/wiki/Vulkan_(API)">Vulkan</link> is a
+      graphics and compute API for GPUs. It is used directly by games or indirectly though
+      compatibility layers like <link xlink:href="https://github.com/doitsujin/dxvk/wiki">DXVK</link>.
+    </para>
+
+    <para>
+     By default, if <xref linkend="opt-hardware.opengl.driSupport"/> is enabled,
+     <package>mesa</package> is installed and provides Vulkan for supported hardware.
+    </para>
+
+    <para>
+      Similar to OpenCL, Vulkan drivers are loaded through the <emphasis>Installable Client
+      Driver</emphasis> (ICD) mechanism. ICD files for Vulkan are JSON files that specify
+      the path to the driver library and the supported Vulkan version. All successfully
+      loaded drivers are exposed to the application as different GPUs.
+      In NixOS, there are two ways to make ICD files visible to Vulkan applications: an
+      environment variable and a module option.
+    </para>
+
+    <para>
+      The first option is through the <varname>VK_ICD_FILENAMES</varname>
+      environment variable. This variable can contain multiple JSON files, separated by
+      <literal>:</literal>. For example:
+
+      <screen><prompt>$</prompt> export \
+  VK_ICD_FILENAMES=`nix-build '&lt;nixpkgs&gt;' --no-out-link -A amdvlk`/share/vulkan/icd.d/amd_icd64.json</screen>
+    </para>
+
+    <para>
+      The second mechanism is to add the Vulkan driver package to
+      <xref linkend="opt-hardware.opengl.extraPackages"/>. This links the
+      ICD file under <filename>/run/opengl-driver</filename>, where it will
+      be visible to the ICD loader.
+    </para>
+
+    <para>
+      The proper installation of Vulkan drivers can be verified through
+      the <command>vulkaninfo</command> command of the <package>vulkan-tools</package>
+      package. This command will report the hardware devices and drivers found,
+      in this example output amdvlk and radv:
+    </para>
+
+    <screen><prompt>$</prompt> vulkaninfo | grep GPU
+                GPU id  : 0 (Unknown AMD GPU)
+                GPU id  : 1 (AMD RADV NAVI10 (LLVM 9.0.1))
+     ...
+GPU0:
+        deviceType     = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU
+        deviceName     = Unknown AMD GPU
+GPU1:
+        deviceType     = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU</screen>
+
+    <para>
+      A simple graphical application that uses Vulkan is <command>vkcube</command>
+      from the <package>vulkan-tools</package> package.
+    </para>
+
+    <section xml:id="sec-gpu-accel-vulkan-amd">
+      <title>AMD</title>
+
+      <para>
+	Modern AMD <link
+	xlink:href="https://en.wikipedia.org/wiki/Graphics_Core_Next">Graphics
+	Core Next</link> (GCN) GPUs are supported through either radv, which is
+	part of <package>mesa</package>, or the <package>amdvlk</package> package.
+	Adding the <package>amdvlk</package> package to
+	<xref linkend="opt-hardware.opengl.extraPackages"/> makes both drivers
+	available for applications and lets them choose. A specific driver can
+	be forced as follows:
+
+	<programlisting><xref linkend="opt-hardware.opengl.extraPackages"/> = [
+  pkgs.<package>amdvlk</package>
+];
+
+# To enable Vulkan support for 32-bit applications, also add:
+<xref linkend="opt-hardware.opengl.extraPackages32"/> = [
+  pkgs.driversi686Linux.<package>amdvlk</package>
+];
+
+# For amdvlk
+<xref linkend="opt-environment.variables"/>.VK_ICD_FILENAMES =
+   "/run/opengl-driver/share/vulkan/icd.d/amd_icd64.json";
+# For radv
+<xref linkend="opt-environment.variables"/>.VK_ICD_FILENAMES =
+  "/run/opengl-driver/share/vulkan/icd.d/radeon_icd.x86_64.json";
+</programlisting>
+      </para>
+    </section>
+  </section>
+
+  <section xml:id="sec-gpu-accel-common-issues">
+   <title>Common issues</title>
+
+   <section xml:id="sec-gpu-accel-common-issues-permissions">
+    <title>User permissions</title>
+
+    <para>
+     Except where noted explicitly, it should not be necessary to
+     adjust user permissions to use these acceleration APIs. In the default
+     configuration, GPU devices have world-read/write permissions
+     (<filename>/dev/dri/renderD*</filename>) or are tagged as
+     <code>uaccess</code> (<filename>/dev/dri/card*</filename>).  The
+     access control lists of devices with the <varname>uaccess</varname>
+     tag will be updated automatically when a user logs in through
+     <command>systemd-logind</command>. For example, if the user
+     <emphasis>jane</emphasis> is logged in, the access control list
+     should look as follows:
+
+     <screen><prompt>$</prompt> getfacl /dev/dri/card0
+# file: dev/dri/card0
+# owner: root
+# group: video
+user::rw-
+user:jane:rw-
+group::rw-
+mask::rw-
+other::---</screen>
+
+     If you disabled (this functionality of) <command>systemd-logind</command>,
+     you may need to add the user to the <code>video</code> group and
+     log in again.
+    </para>
+   </section>
+
+   <section xml:id="sec-gpu-accel-common-issues-mixing-nixpkgs">
+    <title>Mixing different versions of nixpkgs</title>
+
+    <para>
+     The <emphasis>Installable Client Driver</emphasis> (ICD)
+     mechanism used by OpenCL and Vulkan loads runtimes into its address
+     space using <code>dlopen</code>. Mixing an ICD loader mechanism and
+     runtimes from different version of nixpkgs may not work. For example,
+     if the ICD loader uses an older version of <package>glibc</package>
+     than the runtime, the runtime may not be loadable due to
+     missing symbols. Unfortunately, the loader will generally be quiet
+     about such issues.
+    </para>
+
+    <para>
+     If you suspect that you are running into library version mismatches
+     between an ICL loader and a runtime, you could run an application with
+     the <code>LD_DEBUG</code> variable set to get more diagnostic
+     information. For example, OpenCL can be tested with
+     <code>LD_DEBUG=files clinfo</code>, which should report missing
+     symbols.
+    </para>
+   </section>
+  </section>
+</chapter>
diff --git a/nixos/doc/manual/configuration/ipv4-config.xml b/nixos/doc/manual/configuration/ipv4-config.xml
index 71ddf41491baf..884becf0979a0 100644
--- a/nixos/doc/manual/configuration/ipv4-config.xml
+++ b/nixos/doc/manual/configuration/ipv4-config.xml
@@ -10,7 +10,7 @@
   automatically configure network interfaces. However, you can configure an
   interface manually as follows:
 <programlisting>
-<link linkend="opt-networking.interfaces._name__.ipv4.addresses">networking.interfaces.eth0.ipv4.addresses</link> = [ {
+<link linkend="opt-networking.interfaces._name_.ipv4.addresses">networking.interfaces.eth0.ipv4.addresses</link> = [ {
   address = "192.168.1.2";
   prefixLength = 24;
 } ];
diff --git a/nixos/doc/manual/configuration/ipv6-config.xml b/nixos/doc/manual/configuration/ipv6-config.xml
index 675a5d9a260dc..7b89b4092be7d 100644
--- a/nixos/doc/manual/configuration/ipv6-config.xml
+++ b/nixos/doc/manual/configuration/ipv6-config.xml
@@ -26,7 +26,7 @@
   As with IPv4 networking interfaces are automatically configured via DHCPv6.
   You can configure an interface manually:
 <programlisting>
-<link linkend="opt-networking.interfaces._name__.ipv6.addresses">networking.interfaces.eth0.ipv6.addresses</link> = [ {
+<link linkend="opt-networking.interfaces._name_.ipv6.addresses">networking.interfaces.eth0.ipv6.addresses</link> = [ {
   address = "fe00:aa:bb:cc::2";
   prefixLength = 64;
 } ];
diff --git a/nixos/doc/manual/configuration/luks-file-systems.xml b/nixos/doc/manual/configuration/luks-file-systems.xml
index d3007843d68bd..8a8168c095f08 100644
--- a/nixos/doc/manual/configuration/luks-file-systems.xml
+++ b/nixos/doc/manual/configuration/luks-file-systems.xml
@@ -30,7 +30,7 @@ Enter passphrase for /dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d: ***
   <filename>/</filename>, add the following to
   <filename>configuration.nix</filename>:
 <programlisting>
-<link linkend="opt-boot.initrd.luks.devices._name__.device">boot.initrd.luks.devices.crypted.device</link> = "/dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d";
+<link linkend="opt-boot.initrd.luks.devices._name_.device">boot.initrd.luks.devices.crypted.device</link> = "/dev/disk/by-uuid/3f6b0024-3a44-4fde-a43a-767b872abe5d";
 <xref linkend="opt-fileSystems"/>."/".device = "/dev/mapper/crypted";
 </programlisting>
   Should grub be used as bootloader, and <filename>/boot</filename> is located
@@ -60,13 +60,13 @@ Added to key to device /dev/sda2, slot: 2
   To ensure that this file system is decrypted using the FIDO2 compatible key, add the following to <filename>configuration.nix</filename>:
 <programlisting>
 <link linkend="opt-boot.initrd.luks.fido2Support">boot.initrd.luks.fido2Support</link> = true;
-<link linkend="opt-boot.initrd.luks.devices._name__.fido2.credential">boot.initrd.luks.devices."/dev/sda2".fido2.credential</link> = "f1d00200108b9d6e849a8b388da457688e3dd653b4e53770012d8f28e5d3b269865038c346802f36f3da7278b13ad6a3bb6a1452e24ebeeaa24ba40eef559b1b287d2a2f80b7";
+<link linkend="opt-boot.initrd.luks.devices._name_.fido2.credential">boot.initrd.luks.devices."/dev/sda2".fido2.credential</link> = "f1d00200108b9d6e849a8b388da457688e3dd653b4e53770012d8f28e5d3b269865038c346802f36f3da7278b13ad6a3bb6a1452e24ebeeaa24ba40eef559b1b287d2a2f80b7";
 </programlisting>
 
   You can also use the FIDO2 passwordless setup, but for security reasons, you might want to enable it only when your device is PIN protected, such as <link xlink:href="https://trezor.io/">Trezor</link>.
 
 <programlisting>
-<link linkend="opt-boot.initrd.luks.devices._name__.fido2.passwordLess">boot.initrd.luks.devices."/dev/sda2".fido2.passwordLess</link> = true;
+<link linkend="opt-boot.initrd.luks.devices._name_.fido2.passwordLess">boot.initrd.luks.devices."/dev/sda2".fido2.passwordLess</link> = true;
 </programlisting>
   </para>
  </section>
diff --git a/nixos/doc/manual/configuration/network-manager.xml b/nixos/doc/manual/configuration/network-manager.xml
index 3953e0ffe851a..94d229fd803f5 100644
--- a/nixos/doc/manual/configuration/network-manager.xml
+++ b/nixos/doc/manual/configuration/network-manager.xml
@@ -19,7 +19,7 @@
   All users that should have permission to change network settings must belong
   to the <code>networkmanager</code> group:
 <programlisting>
-<link linkend="opt-users.users._name__.extraGroups">users.users.alice.extraGroups</link> = [ "networkmanager" ];
+<link linkend="opt-users.users._name_.extraGroups">users.users.alice.extraGroups</link> = [ "networkmanager" ];
 </programlisting>
  </para>
 
diff --git a/nixos/doc/manual/configuration/profiles/demo.xml b/nixos/doc/manual/configuration/profiles/demo.xml
index 395a5ec357c90..bc801bb3dc5b8 100644
--- a/nixos/doc/manual/configuration/profiles/demo.xml
+++ b/nixos/doc/manual/configuration/profiles/demo.xml
@@ -9,7 +9,6 @@
   This profile just enables a <systemitem class="username">demo</systemitem>
   user, with password <literal>demo</literal>, uid <literal>1000</literal>,
   <systemitem class="groupname">wheel</systemitem> group and
-  <link linkend="opt-services.xserver.displayManager.sddm.autoLogin"> autologin
-  in the SDDM display manager</link>.
+  <link linkend="opt-services.xserver.displayManager.autoLogin">autologin in the SDDM display manager</link>.
  </para>
 </section>
diff --git a/nixos/doc/manual/configuration/ssh.xml b/nixos/doc/manual/configuration/ssh.xml
index a4af1b96583d8..95ad3edff9352 100644
--- a/nixos/doc/manual/configuration/ssh.xml
+++ b/nixos/doc/manual/configuration/ssh.xml
@@ -20,7 +20,7 @@
   follows:
 <!-- FIXME: this might not work if the user is unmanaged. -->
 <programlisting>
-<link linkend="opt-users.users._name__.openssh.authorizedKeys.keys">users.users.alice.openssh.authorizedKeys.keys</link> =
+<link linkend="opt-users.users._name_.openssh.authorizedKeys.keys">users.users.alice.openssh.authorizedKeys.keys</link> =
   [ "ssh-dss AAAAB3NzaC1kc3MAAACBAPIkGWVEt4..." ];
 </programlisting>
  </para>
diff --git a/nixos/doc/manual/configuration/user-mgmt.xml b/nixos/doc/manual/configuration/user-mgmt.xml
index 4b1710f3a2b11..68324cc85b547 100644
--- a/nixos/doc/manual/configuration/user-mgmt.xml
+++ b/nixos/doc/manual/configuration/user-mgmt.xml
@@ -11,11 +11,11 @@
   that a user account named <literal>alice</literal> shall exist:
 <programlisting>
 <xref linkend="opt-users.users"/>.alice = {
-  <link linkend="opt-users.users._name__.isNormalUser">isNormalUser</link> = true;
-  <link linkend="opt-users.users._name__.home">home</link> = "/home/alice";
-  <link linkend="opt-users.users._name__.description">description</link> = "Alice Foobar";
-  <link linkend="opt-users.users._name__.extraGroups">extraGroups</link> = [ "wheel" "networkmanager" ];
-  <link linkend="opt-users.users._name__.openssh.authorizedKeys.keys">openssh.authorizedKeys.keys</link> = [ "ssh-dss AAAAB3Nza... alice@foobar" ];
+  <link linkend="opt-users.users._name_.isNormalUser">isNormalUser</link> = true;
+  <link linkend="opt-users.users._name_.home">home</link> = "/home/alice";
+  <link linkend="opt-users.users._name_.description">description</link> = "Alice Foobar";
+  <link linkend="opt-users.users._name_.extraGroups">extraGroups</link> = [ "wheel" "networkmanager" ];
+  <link linkend="opt-users.users._name_.openssh.authorizedKeys.keys">openssh.authorizedKeys.keys</link> = [ "ssh-dss AAAAB3Nza... alice@foobar" ];
 };
 </programlisting>
   Note that <literal>alice</literal> is a member of the
@@ -36,7 +36,7 @@
   account will cease to exist. Also, imperative commands for managing users and
   groups, such as useradd, are no longer available. Passwords may still be
   assigned by setting the user's
-  <link linkend="opt-users.users._name__.hashedPassword">hashedPassword</link>
+  <link linkend="opt-users.users._name_.hashedPassword">hashedPassword</link>
   option. A hashed password can be generated using <command>mkpasswd -m
   sha-512</command> after installing the <literal>mkpasswd</literal> package.
  </para>
diff --git a/nixos/doc/manual/configuration/x-windows.xml b/nixos/doc/manual/configuration/x-windows.xml
index 110712baf5f16..18f0be5e7f394 100644
--- a/nixos/doc/manual/configuration/x-windows.xml
+++ b/nixos/doc/manual/configuration/x-windows.xml
@@ -90,10 +90,50 @@
   using lightdm for a user <literal>alice</literal>:
 <programlisting>
 <xref linkend="opt-services.xserver.displayManager.lightdm.enable"/> = true;
-<xref linkend="opt-services.xserver.displayManager.lightdm.autoLogin.enable"/> = true;
-<xref linkend="opt-services.xserver.displayManager.lightdm.autoLogin.user"/> = "alice";
+<xref linkend="opt-services.xserver.displayManager.autoLogin.enable"/> = true;
+<xref linkend="opt-services.xserver.displayManager.autoLogin.user"/> = "alice";
 </programlisting>
-  The options are named identically for all other display managers.
+  </para>
+ </simplesect>
+ <simplesect xml:id="sec-x11--graphics-cards-intel">
+  <title>Intel Graphics drivers</title>
+  <para>
+   There are two choices for Intel Graphics drivers in X.org:
+   <literal>modesetting</literal> (included in the <package>xorg-server</package> itself)
+   and <literal>intel</literal> (provided by the package <package>xf86-video-intel</package>).
+  </para>
+  <para>
+   The default and recommended is <literal>modesetting</literal>.
+   It is a generic driver which uses the kernel
+   <link xlink:href="https://en.wikipedia.org/wiki/Mode_setting">mode setting</link>
+   (KMS) mechanism. It supports Glamor (2D graphics acceleration via OpenGL)
+   and is actively maintained but may perform worse in some cases (like in old chipsets).
+  </para>
+  <para>
+   The second driver, <literal>intel</literal>, is specific to Intel GPUs,
+   but not recommended by most distributions: it lacks several modern features
+   (for example, it doesn't support Glamor) and the package hasn't been officially
+   updated since 2015.
+  </para>
+  <para>
+   The results vary depending on the hardware, so you may have to try both drivers.
+   Use the option <xref linkend="opt-services.xserver.videoDrivers"/> to set one.
+   The recommended configuration for modern systems is:
+<programlisting>
+  <xref linkend="opt-services.xserver.videoDrivers"/> = [ "modesetting" ];
+  <xref linkend="opt-services.xserver.useGlamor"/> = true;
+</programlisting>
+   If you experience screen tearing no matter what, this configuration was
+   reported to resolve the issue:
+<programlisting>
+  <xref linkend="opt-services.xserver.videoDrivers"/> = [ "intel" ];
+  <xref linkend="opt-services.xserver.deviceSection"/> = ''
+    Option "DRI" "2"
+    Option "TearFree" "true"
+  '';
+</programlisting>
+   Note that this will likely downgrade the performance compared to
+  <literal>modesetting</literal> or <literal>intel</literal> with DRI 3 (default).
   </para>
  </simplesect>
  <simplesect xml:id="sec-x11-graphics-cards-nvidia">
diff --git a/nixos/doc/manual/development/freeform-modules.xml b/nixos/doc/manual/development/freeform-modules.xml
new file mode 100644
index 0000000000000..257e6b11bf014
--- /dev/null
+++ b/nixos/doc/manual/development/freeform-modules.xml
@@ -0,0 +1,68 @@
+<section xmlns="http://docbook.org/ns/docbook"
+        xmlns:xlink="http://www.w3.org/1999/xlink"
+        xmlns:xi="http://www.w3.org/2001/XInclude"
+        version="5.0"
+        xml:id="sec-freeform-modules">
+ <title>Freeform modules</title>
+ <para>
+  Freeform modules allow you to define values for option paths that have not been declared explicitly. This can be used to add attribute-specific types to what would otherwise have to be <literal>attrsOf</literal> options in order to accept all attribute names.
+ </para>
+ <para>
+  This feature can be enabled by using the attribute <literal>freeformType</literal> to define a freeform type. By doing this, all assignments without an associated option will be merged using the freeform type and combined into the resulting <literal>config</literal> set. Since this feature nullifies name checking for entire option trees, it is only recommended for use in submodules.
+ </para>
+ <example xml:id="ex-freeform-module">
+  <title>Freeform submodule</title>
+  <para>
+   The following shows a submodule assigning a freeform type that allows arbitrary attributes with <literal>str</literal> values below <literal>settings</literal>, but also declares an option for the <literal>settings.port</literal> attribute to have it type-checked and assign a default value. See <xref linkend="ex-settings-typed-attrs"/> for a more complete example.
+  </para>
+ <programlisting>
+{ lib, config, ... }: {
+
+  options.settings = lib.mkOption {
+    type = lib.types.submodule {
+
+      freeformType = with lib.types; attrsOf str;
+
+      # We want this attribute to be checked for the correct type
+      options.port = lib.mkOption {
+        type = lib.types.port;
+        # Declaring the option also allows defining a default value
+        default = 8080;
+      };
+
+    };
+  };
+}
+ </programlisting>
+ <para>
+  And the following shows what such a module then allows
+ </para>
+ <programlisting>
+{
+  # Not a declared option, but the freeform type allows this
+  settings.logLevel = "debug";
+
+  # Not allowed because the the freeform type only allows strings
+  # settings.enable = true;
+
+  # Allowed because there is a port option declared
+  settings.port = 80;
+
+  # Not allowed because the port option doesn't allow strings
+  # settings.port = "443";
+}
+ </programlisting>
+ </example>
+ <note>
+  <para>
+   Freeform attributes cannot depend on other attributes of the same set without infinite recursion:
+<programlisting>
+{
+  # This throws infinite recursion encountered
+  settings.logLevel = lib.mkIf (config.settings.port == 80) "debug";
+}
+</programlisting>
+   To prevent this, declare options for all attributes that need to depend on others. For above example this means to declare <literal>logLevel</literal> to be an option.
+  </para>
+ </note>
+</section>
diff --git a/nixos/doc/manual/development/option-types.xml b/nixos/doc/manual/development/option-types.xml
index 957349ad1811a..3d2191e2f3f31 100644
--- a/nixos/doc/manual/development/option-types.xml
+++ b/nixos/doc/manual/development/option-types.xml
@@ -23,16 +23,6 @@
   <variablelist>
    <varlistentry>
     <term>
-     <varname>types.attrs</varname>
-    </term>
-    <listitem>
-     <para>
-      A free-form attribute set.
-     </para>
-    </listitem>
-   </varlistentry>
-   <varlistentry>
-    <term>
      <varname>types.bool</varname>
     </term>
     <listitem>
@@ -64,6 +54,64 @@
      </para>
     </listitem>
    </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>types.anything</varname>
+    </term>
+    <listitem>
+     <para>
+      A type that accepts any value and recursively merges attribute sets together.
+      This type is recommended when the option type is unknown.
+      <example xml:id="ex-types-anything">
+       <title><literal>types.anything</literal> Example</title>
+       <para>
+        Two definitions of this type like
+<programlisting>
+{
+  str = lib.mkDefault "foo";
+  pkg.hello = pkgs.hello;
+  fun.fun = x: x + 1;
+}
+</programlisting>
+<programlisting>
+{
+  str = lib.mkIf true "bar";
+  pkg.gcc = pkgs.gcc;
+  fun.fun = lib.mkForce (x: x + 2);
+}
+</programlisting>
+        will get merged to
+<programlisting>
+{
+  str = "bar";
+  pkg.gcc = pkgs.gcc;
+  pkg.hello = pkgs.hello;
+  fun.fun = x: x + 2;
+}
+</programlisting>
+       </para>
+      </example>
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
+     <varname>types.attrs</varname>
+    </term>
+    <listitem>
+     <para>
+      A free-form attribute set.
+      <warning><para>
+       This type will be deprecated in the future because it doesn't recurse
+       into attribute sets, silently drops earlier attribute definitions, and
+       doesn't discharge <literal>lib.mkDefault</literal>, <literal>lib.mkIf
+       </literal> and co. For allowing arbitrary attribute sets, prefer
+       <literal>types.attrsOf types.anything</literal> instead which doesn't
+       have these problems.
+      </para></warning>
+     </para>
+    </listitem>
+   </varlistentry>
   </variablelist>
 
   <para>
@@ -387,17 +435,6 @@
    </varlistentry>
    <varlistentry>
     <term>
-     <varname>types.loaOf</varname> <replaceable>t</replaceable>
-    </term>
-    <listitem>
-     <para>
-      An attribute set or a list of <replaceable>t</replaceable> type. Multiple
-      definitions are merged according to the value.
-     </para>
-    </listitem>
-   </varlistentry>
-   <varlistentry>
-    <term>
      <varname>types.nullOr</varname> <replaceable>t</replaceable>
     </term>
     <listitem>
diff --git a/nixos/doc/manual/development/releases.xml b/nixos/doc/manual/development/releases.xml
index 8abc66dfec192..cd68a428a6fbd 100755
--- a/nixos/doc/manual/development/releases.xml
+++ b/nixos/doc/manual/development/releases.xml
@@ -8,24 +8,26 @@
   <title>Release process</title>
 
   <para>
-   Going through an example of releasing NixOS 17.09:
+   Going through an example of releasing NixOS 19.09:
   </para>
 
   <section xml:id="one-month-before-the-beta">
    <title>One month before the beta</title>
 
-   <itemizedlist spacing="compact">
+   <itemizedlist>
     <listitem>
      <para>
-      Send an email to the nix-devel mailinglist as a warning about upcoming
-      beta "feature freeze" in a month.
+      Create an announcement on <link xlink:href="https://discourse.nixos.org">Discourse</link> as a warning about upcoming beta <quote>feature freeze</quote> in a month. <link xlink:href="https://discourse.nixos.org/t/nixos-19-09-feature-freeze/3707">See this post as an example</link>.
      </para>
     </listitem>
     <listitem>
      <para>
-      Discuss with Eelco Dolstra and the community (via IRC, ML) about what
-      will reach the deadline. Any issue or Pull Request targeting the release
-      should be included in the release milestone.
+      Discuss with Eelco Dolstra and the community (via IRC, ML) about what will reach the deadline. Any issue or Pull Request targeting the release should be included in the release milestone.
+     </para>
+    </listitem>
+    <listitem>
+     <para>
+      Remove attributes that we know we will not be able to support, especially if there is a stable alternative. E.g. Check that our Linux kernels’ <link xlink:href="https://www.kernel.org/category/releases.html">projected end-of-life</link> are after our release projected end-of-life.
      </para>
     </listitem>
    </itemizedlist>
@@ -34,113 +36,113 @@
   <section xml:id="at-beta-release-time">
    <title>At beta release time</title>
 
-   <itemizedlist spacing="compact">
+   <orderedlist>
     <listitem>
      <para>
-      <link xlink:href="https://github.com/NixOS/nixpkgs/issues/13559">Create
-      an issue for tracking Zero Hydra Failures progress. ZHF is an effort to
-      get build failures down to zero.</link>
+      From the master branch run:
      </para>
+<programlisting>
+git checkout -b release-19.09
+</programlisting>
     </listitem>
     <listitem>
      <para>
-      <literal>git tag -a -s -m &quot;Release 17.09-beta&quot; 17.09-beta
-      &amp;&amp; git push origin 17.09-beta</literal>
+      <link xlink:href="https://github.com/NixOS/nixpkgs/commit/10e61bf5be57736035ec7a804cb0bf3d083bf2cf#diff-9c798092bac0caeb5c52d509be0ca263R69">Bump the <literal>system.defaultChannel</literal> attribute in <literal>nixos/modules/misc/version.nix</literal></link>
      </para>
     </listitem>
     <listitem>
      <para>
-      From the master branch run <literal>git checkout -b
-      release-17.09</literal>.
+      <link xlink:href="https://github.com/NixOS/nixpkgs/commit/10e61bf5be57736035ec7a804cb0bf3d083bf2cf#diff-831e8d9748240fb23e6734fdc2a6d16eR15">Update <literal>versionSuffix</literal> in <literal>nixos/release.nix</literal></link>
      </para>
     </listitem>
+   </orderedlist>
+
+   <para>
+    To get the commit count, use the following command:
+   </para>
+
+<programlisting>
+git rev-list --count release-19.09
+</programlisting>
+
+   <orderedlist>
     <listitem>
      <para>
-      <link xlink:href="https://github.com/NixOS/nixos-org-configurations/pull/18">
-      Make sure a channel is created at https://nixos.org/channels/. </link>
+      Edit changelog at <literal>nixos/doc/manual/release-notes/rl-1909.xml</literal>.
      </para>
+     <itemizedlist>
+      <listitem>
+       <para>
+        Get all new NixOS modules:
+       </para>
+<programlisting>
+git diff release-19.03..release-19.09 nixos/modules/module-list.nix | grep ^+
+</programlisting>
+      </listitem>
+      <listitem>
+       <para>
+        Note systemd, kernel, glibc, desktop environment, and Nix upgrades.
+       </para>
+      </listitem>
+     </itemizedlist>
     </listitem>
     <listitem>
      <para>
-      <link xlink:href="https://github.com/NixOS/nixpkgs/compare/bdf161ed8d21...6b63c4616790">
-      Bump the <literal>system.defaultChannel</literal> attribute in
-      <literal>nixos/modules/misc/version.nix</literal> </link>
+      Tag the release:
      </para>
+<programlisting>
+git tag --annotate --message="Release 19.09-beta" 19.09-beta
+git push upstream 19.09-beta
+</programlisting>
     </listitem>
     <listitem>
      <para>
-      <link xlink:href="https://github.com/NixOS/nixpkgs/commit/d6b08acd1ccac0d9d502c4b635e00b04d3387f06">
-      Update <literal>versionSuffix</literal> in
-      <literal>nixos/release.nix</literal></link>, use
-      <literal>git rev-list --count 17.09-beta</literal>
-      to get the commit count.
+      <link xlink:href="https://github.com/NixOS/nixpkgs/commit/01268fda85b7eee4e462c873d8654f975067731f#diff-2bc0e46110b507d6d5a344264ef15adaR1">On the <literal>master</literal> branch, increment the <literal>.version</literal> file</link>
      </para>
+<programlisting>
+echo -n "20.03" > .version
+</programlisting>
     </listitem>
     <listitem>
      <para>
-      <literal>echo -n &quot;18.03&quot; &gt; .version</literal> on master.
+      <link xlink:href="https://github.com/NixOS/nixpkgs/commit/01268fda85b7eee4e462c873d8654f975067731f#diff-03f3d41b68f62079c55001f1a1c55c1dR137">Update <literal>codeName</literal> in <literal>lib/trivial.nix</literal></link> This will be the name for the next release.
      </para>
     </listitem>
     <listitem>
      <para>
-      <link xlink:href="https://github.com/NixOS/nixpkgs/commit/b8a4095003e27659092892a4708bb3698231a842">
-      Pick a new name for the unstable branch. </link>
+      <link xlink:href="https://github.com/NixOS/nixpkgs/commit/01268fda85b7eee4e462c873d8654f975067731f#diff-e7ee5ff686cdcc513ca089d6e5682587R11">Create a new release notes file for the upcoming release + 1</link>, in our case this is <literal>rl-2003.xml</literal>.
      </para>
     </listitem>
     <listitem>
      <para>
-      Create a new release notes file for the upcoming release + 1, in this
-      case <literal>rl-1803.xml</literal>.
+      Contact the infrastructure team to create the necessary Hydra Jobsets.
      </para>
     </listitem>
     <listitem>
      <para>
-      Create two Hydra jobsets: release-17.09 and release-17.09-small with
-      <literal>stableBranch</literal> set to false.
+      <link xlink:href="https://github.com/NixOS/nixos-org-configurations/blob/master/channels.nix">Create a channel at https://nixos.org/channels by creating a PR to nixos-org-configurations, changing <literal>channels.nix</literal></link>
      </para>
     </listitem>
     <listitem>
      <para>
-      Remove attributes that we know we will not be able to support,
-      especially if there is a stable alternative. E.g. Check that our
-      Linux kernels'
-      <link xlink:href="https://www.kernel.org/category/releases.html">
-      projected end-of-life</link> are after our release projected
-      end-of-life
+      Get all Hydra jobsets for the release to have their first evaluation.
      </para>
     </listitem>
     <listitem>
      <para>
-      Edit changelog at
-      <literal>nixos/doc/manual/release-notes/rl-1709.xml</literal> (double
-      check desktop versions are noted)
+      <link xlink:href="https://github.com/NixOS/nixpkgs/issues/13559">Create an issue for tracking Zero Hydra Failures progress. ZHF is an effort to get build failures down to zero.</link>
      </para>
-     <itemizedlist spacing="compact">
-      <listitem>
-       <para>
-        Get all new NixOS modules <literal>git diff
-        release-17.03..release-17.09 nixos/modules/module-list.nix|grep
-        ^+</literal>
-       </para>
-      </listitem>
-      <listitem>
-       <para>
-        Note systemd, kernel, glibc and Nix upgrades.
-       </para>
-      </listitem>
-     </itemizedlist>
     </listitem>
-   </itemizedlist>
+   </orderedlist>
   </section>
 
   <section xml:id="during-beta">
    <title>During Beta</title>
 
-   <itemizedlist spacing="compact">
+   <itemizedlist>
     <listitem>
      <para>
-      Monitor the master branch for bugfixes and minor updates and cherry-pick
-      them to the release branch.
+      Monitor the master branch for bugfixes and minor updates and cherry-pick them to the release branch.
      </para>
     </listitem>
    </itemizedlist>
@@ -149,7 +151,7 @@
   <section xml:id="before-the-final-release">
    <title>Before the final release</title>
 
-   <itemizedlist spacing="compact">
+   <itemizedlist>
     <listitem>
      <para>
       Re-check that the release notes are complete.
@@ -157,21 +159,17 @@
     </listitem>
     <listitem>
      <para>
-      Release Nix (currently only Eelco Dolstra can do that).
-      <link xlink:href="https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/installer/tools/nix-fallback-paths.nix">
-      Make sure fallback is updated. </link>
+      Release Nix (currently only Eelco Dolstra can do that). <link xlink:href="https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/installer/tools/nix-fallback-paths.nix">Make sure fallback is updated.</link>
      </para>
     </listitem>
     <listitem>
      <para>
-      <link xlink:href="https://github.com/NixOS/nixpkgs/commit/40fd9ae3ac8048758abdcfc7d28a78b5f22fe97e">
-      Update README.md with new stable NixOS version information. </link>
+      <link xlink:href="https://github.com/NixOS/nixpkgs/commit/40fd9ae3ac8048758abdcfc7d28a78b5f22fe97e">Update README.md with new stable NixOS version information.</link>
      </para>
     </listitem>
     <listitem>
      <para>
-      Change <literal>stableBranch</literal> to <literal>true</literal> in Hydra and wait for
-      the channel to update.
+      Change <literal>stableBranch</literal> to <literal>true</literal> in Hydra and wait for the channel to update.
      </para>
     </listitem>
    </itemizedlist>
@@ -180,76 +178,143 @@
   <section xml:id="at-final-release-time">
    <title>At final release time</title>
 
-   <itemizedlist spacing="compact">
+   <orderedlist>
     <listitem>
      <para>
-      <literal>git tag -s -a -m &quot;Release 15.09&quot; 15.09</literal>
+      Update <xref linkend="sec-upgrading" /> section of the manual to match new stable release version.
      </para>
     </listitem>
     <listitem>
      <para>
-      Update "Chapter 4. Upgrading NixOS" section of the manual to match
-      new stable release version.
+      Update <literal>rl-1909.xml</literal> with the release date.
      </para>
     </listitem>
     <listitem>
      <para>
-      Update the
-      <link xlink:href="https://github.com/NixOS/nixos-homepage/commit/2a37975d5a617ecdfca94696242b6f32ffcba9f1"><code>NIXOS_SERIES</code></link>
-      in the
-      <link xlink:href="https://github.com/NixOS/nixos-homepage">nixos-homepage</link>
-      repository.
+      Tag the final release
      </para>
+<programlisting>
+git tag --annotate --message="Release 19.09" 19.09
+git push upstream 19.09
+</programlisting>
+    </listitem>
+    <listitem>
+     <para>
+      Update <link xlink:href="https://github.com/NixOS/nixos-homepage">nixos-homepage</link> for the release.
+     </para>
+     <orderedlist>
+      <listitem>
+       <para>
+        <link xlink:href="https://github.com/NixOS/nixos-homepage/blob/47ac3571c4d71e841fd4e6c6e1872e762b9c4942/Makefile#L1">Update <literal>NIXOS_SERIES</literal> in the <literal>Makefile</literal></link>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <link xlink:href="https://github.com/NixOS/nixos-homepage/blob/47ac3571c4d71e841fd4e6c6e1872e762b9c4942/nixos-release.tt#L1">Update <literal>nixos-release.tt</literal> with the new NixOS version</link>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <link xlink:href="https://github.com/NixOS/nixos-homepage/blob/47ac3571c4d71e841fd4e6c6e1872e762b9c4942/flake.nix#L10">Update the <literal>flake.nix</literal> input <literal>released-nixpkgs</literal> to 19.09</link>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        Run <literal>./update.sh</literal> (this updates flake.lock to updated channel).
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <link xlink:href="https://github.com/NixOS/nixos-homepage/blob/a5626c71c03a2dd69086564e56f1a230a2bb177a/logo/nixos-logo-19.09-loris-lores.png">Add a compressed version of the NixOS logo for 19.09</link>.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <link xlink:href="https://github.com/NixOS/nixos-homepage/commit/a5626c71c03a2dd69086564e56f1a230a2bb177a#diff-9cdc6434d3e4fd93a6e5bb0a531a7c71R5">Compose a news item for the website RSS feed</link>.
+       </para>
+      </listitem>
+     </orderedlist>
     </listitem>
     <listitem>
      <para>
-      Get number of commits for the release: <literal>git log
-      release-14.04..release-14.12 --format=%an|wc -l</literal>
+      Create a new topic on <link xlink:href="https://discourse.nixos.org/">the Discourse instance</link> to announce the release.
      </para>
     </listitem>
+   </orderedlist>
+
+   <para>
+    You should include the following information:
+   </para>
+
+   <itemizedlist>
     <listitem>
      <para>
-      Commits by contributor: <literal>git log release-14.04..release-14.12
-      --format=%an|sort|uniq -c|sort -rn</literal>
+      Number of commits for the release:
      </para>
+<programlisting>
+bash git log release-19.03..release-19.09 --format=%an | wc -l
+</programlisting>
     </listitem>
     <listitem>
      <para>
-      Create a new topic on <link xlink:href="https://discourse.nixos.org/">the
-      Discourse instance</link> to announce the release with the above information.
-      Best to check how previous email was formulated to see what needs to be
-      included.
+      Commits by contributor:
      </para>
+<programlisting>
+git shortlog --summary --numbered release-19.03..release-19.09
+</programlisting>
     </listitem>
    </itemizedlist>
+
+   <para>
+    Best to check how the previous post was formulated to see what needs to be included.
+   </para>
   </section>
  </section>
- <section xml:id="release-managers">
+ <section xml:id="release-management-team">
   <title>Release Management Team</title>
+
   <para>
-   For each release there are two release managers. After each release the
-   release manager having managed two releases steps down and the release
-   management team of the last release appoints a new release manager.
+   For each release there are two release managers. After each release the release manager having managed two releases steps down and the release management team of the last release appoints a new release manager.
   </para>
+
   <para>
-   This makes sure a release management team always consists of one release
-   manager who already has managed one release and one release manager being
-   introduced to their role, making it easier to pass on knowledge and
-   experience.
+   This makes sure a release management team always consists of one release manager who already has managed one release and one release manager being introduced to their role, making it easier to pass on knowledge and experience.
   </para>
+
   <para>
-   Release managers for the current NixOS release are tracked by GitHub team
-   <link xlink:href="https://github.com/orgs/NixOS/teams/nixos-release-managers/members"><literal>@NixOS/nixos-release-managers</literal></link>.
+   Release managers for the current NixOS release are tracked by GitHub team <link xlink:href="https://github.com/orgs/NixOS/teams/nixos-release-managers/members"><literal>@NixOS/nixos-release-managers</literal></link>.
   </para>
+
   <para>
-   A release manager's role and responsibilities are:
+   A release manager’s role and responsibilities are:
   </para>
+
   <itemizedlist>
-   <listitem><para>manage the release process</para></listitem>
-   <listitem><para>start discussions about features and changes for a given release</para></listitem>
-   <listitem><para>create a roadmap</para></listitem>
-   <listitem><para>release in cooperation with Eelco Dolstra</para></listitem>
-   <listitem><para>decide which bug fixes, features, etc... get backported after a release</para></listitem>
+   <listitem>
+    <para>
+     manage the release process
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     start discussions about features and changes for a given release
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     create a roadmap
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     release in cooperation with Eelco Dolstra
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     decide which bug fixes, features, etc… get backported after a release
+    </para>
+   </listitem>
   </itemizedlist>
  </section>
  <section xml:id="release-schedule">
diff --git a/nixos/doc/manual/development/running-nixos-tests-interactively.xml b/nixos/doc/manual/development/running-nixos-tests-interactively.xml
index 31216874c7060..a11a9382764d2 100644
--- a/nixos/doc/manual/development/running-nixos-tests-interactively.xml
+++ b/nixos/doc/manual/development/running-nixos-tests-interactively.xml
@@ -38,7 +38,12 @@ starting VDE switch for network 1
  </para>
 
  <para>
-  The machine state is kept across VM restarts in
-  <filename>/tmp/vm-state-</filename><varname>machinename</varname>.
+   You can re-use the VM states coming from a previous run
+   by setting the <command>--keep-vm-state</command> flag.
+<screen>
+<prompt>$ </prompt>./result/bin/nixos-run-vms --keep-vm-state
+</screen>
+  The machine state is stored in the
+  <filename>$TMPDIR/vm-state-</filename><varname>machinename</varname> directory.
  </para>
 </section>
diff --git a/nixos/doc/manual/development/settings-options.xml b/nixos/doc/manual/development/settings-options.xml
new file mode 100644
index 0000000000000..c99c3af92f894
--- /dev/null
+++ b/nixos/doc/manual/development/settings-options.xml
@@ -0,0 +1,216 @@
+<section xmlns="http://docbook.org/ns/docbook"
+        xmlns:xlink="http://www.w3.org/1999/xlink"
+        xmlns:xi="http://www.w3.org/2001/XInclude"
+        version="5.0"
+        xml:id="sec-settings-options">
+ <title>Options for Program Settings</title>
+
+ <para>
+   Many programs have configuration files where program-specific settings can be declared. File formats can be separated into two categories:
+   <itemizedlist>
+     <listitem>
+       <para>
+         Nix-representable ones: These can trivially be mapped to a subset of Nix syntax. E.g. JSON is an example, since its values like <literal>{"foo":{"bar":10}}</literal> can be mapped directly to Nix: <literal>{ foo = { bar = 10; }; }</literal>. Other examples are INI, YAML and TOML. The following section explains the convention for these settings.
+       </para>
+     </listitem>
+     <listitem>
+       <para>
+         Non-nix-representable ones: These can't be trivially mapped to a subset of Nix syntax. Most generic programming languages are in this group, e.g. bash, since the statement <literal>if true; then echo hi; fi</literal> doesn't have a trivial representation in Nix.
+       </para>
+       <para>
+         Currently there are no fixed conventions for these, but it is common to have a <literal>configFile</literal> option for setting the configuration file path directly. The default value of <literal>configFile</literal> can be an auto-generated file, with convenient options for controlling the contents. For example an option of type <literal>attrsOf str</literal> can be used for representing environment variables which generates a section like <literal>export FOO="foo"</literal>. Often it can also be useful to also include an <literal>extraConfig</literal> option of type <literal>lines</literal> to allow arbitrary text after the autogenerated part of the file.
+       </para>
+     </listitem>
+   </itemizedlist>
+ </para>
+ <section xml:id="sec-settings-nix-representable">
+   <title>Nix-representable Formats (JSON, YAML, TOML, INI, ...)</title>
+   <para>
+     By convention, formats like this are handled with a generic <literal>settings</literal> option, representing the full program configuration as a Nix value. The type of this option should represent the format. The most common formats have a predefined type and string generator already declared under <literal>pkgs.formats</literal>:
+     <variablelist>
+       <varlistentry>
+         <term>
+           <varname>pkgs.formats.json</varname> { }
+         </term>
+         <listitem>
+           <para>
+             A function taking an empty attribute set (for future extensibility) and returning a set with JSON-specific attributes <varname>type</varname> and <varname>generate</varname> as specified <link linkend='pkgs-formats-result'>below</link>.
+           </para>
+         </listitem>
+       </varlistentry>
+       <varlistentry>
+         <term>
+           <varname>pkgs.formats.yaml</varname> { }
+         </term>
+         <listitem>
+           <para>
+             A function taking an empty attribute set (for future extensibility) and returning a set with YAML-specific attributes <varname>type</varname> and <varname>generate</varname> as specified <link linkend='pkgs-formats-result'>below</link>.
+           </para>
+         </listitem>
+       </varlistentry>
+       <varlistentry>
+         <term>
+           <varname>pkgs.formats.ini</varname> { <replaceable>listsAsDuplicateKeys</replaceable> ? false, ... }
+         </term>
+         <listitem>
+           <para>
+             A function taking an attribute set with values
+             <variablelist>
+               <varlistentry>
+                 <term>
+                   <varname>listsAsDuplicateKeys</varname>
+                 </term>
+                 <listitem>
+                   <para>
+                     A boolean for controlling whether list values can be used to represent duplicate INI keys
+                   </para>
+                 </listitem>
+               </varlistentry>
+             </variablelist>
+            It returns a set with INI-specific attributes <varname>type</varname> and <varname>generate</varname> as specified <link linkend='pkgs-formats-result'>below</link>.
+           </para>
+         </listitem>
+       </varlistentry>
+       <varlistentry>
+         <term>
+           <varname>pkgs.formats.toml</varname> { }
+         </term>
+         <listitem>
+           <para>
+             A function taking an empty attribute set (for future extensibility) and returning a set with TOML-specific attributes <varname>type</varname> and <varname>generate</varname> as specified <link linkend='pkgs-formats-result'>below</link>.
+           </para>
+         </listitem>
+       </varlistentry>
+     </variablelist>
+
+   </para>
+   <para xml:id="pkgs-formats-result">
+     These functions all return an attribute set with these values:
+    <variablelist>
+      <varlistentry>
+        <term>
+          <varname>type</varname>
+        </term>
+        <listitem>
+          <para>
+            A module system type representing a value of the format
+          </para>
+        </listitem>
+      </varlistentry>
+      <varlistentry>
+        <term>
+          <varname>generate</varname> <replaceable>filename</replaceable> <replaceable>jsonValue</replaceable>
+        </term>
+        <listitem>
+          <para>
+           A function that can render a value of the format to a file. Returns a file path.
+           <note>
+            <para>
+             This function puts the value contents in the Nix store. So this should be avoided for secrets.
+            </para>
+           </note>
+          </para>
+        </listitem>
+      </varlistentry>
+    </variablelist>
+   </para>
+   <example xml:id="ex-settings-nix-representable">
+     <title>Module with conventional <literal>settings</literal> option</title>
+     <para>
+       The following shows a module for an example program that uses a JSON configuration file. It demonstrates how above values can be used, along with some other related best practices. See the comments for explanations.
+     </para>
+<programlisting>
+{ options, config, lib, pkgs, ... }:
+let
+  cfg = config.services.foo;
+  # Define the settings format used for this program
+  settingsFormat = pkgs.formats.json {};
+in {
+
+  options.services.foo = {
+    enable = lib.mkEnableOption "foo service";
+
+    settings = lib.mkOption {
+      # Setting this type allows for correct merging behavior
+      type = settingsFormat.type;
+      default = {};
+      description = ''
+        Configuration for foo, see
+        &lt;link xlink:href="https://example.com/docs/foo"/&gt;
+        for supported settings.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    # We can assign some default settings here to make the service work by just
+    # enabling it. We use `mkDefault` for values that can be changed without
+    # problems
+    services.foo.settings = {
+      # Fails at runtime without any value set
+      log_level = lib.mkDefault "WARN";
+
+      # We assume systemd's `StateDirectory` is used, so we require this value,
+      # therefore no mkDefault
+      data_path = "/var/lib/foo";
+
+      # Since we use this to create a user we need to know the default value at
+      # eval time
+      user = lib.mkDefault "foo";
+    };
+
+    environment.etc."foo.json".source =
+      # The formats generator function takes a filename and the Nix value
+      # representing the format value and produces a filepath with that value
+      # rendered in the format
+      settingsFormat.generate "foo-config.json" cfg.settings;
+
+    # We know that the `user` attribute exists because we set a default value
+    # for it above, allowing us to use it without worries here
+    users.users.${cfg.settings.user} = {};
+
+    # ...
+  };
+}
+</programlisting>
+   </example>
+   <section xml:id="sec-settings-attrs-options">
+    <title>Option declarations for attributes</title>
+    <para>
+     Some <literal>settings</literal> attributes may deserve some extra care. They may need a different type, default or merging behavior, or they are essential options that should show their documentation in the manual. This can be done using <xref linkend='sec-freeform-modules'/>.
+     <example xml:id="ex-settings-typed-attrs">
+      <title>Declaring a type-checked <literal>settings</literal> attribute</title>
+      <para>
+       We extend above example using freeform modules to declare an option for the port, which will enforce it to be a valid integer and make it show up in the manual.
+      </para>
+<programlisting>
+settings = lib.mkOption {
+  type = lib.types.submodule {
+
+    freeformType = settingsFormat.type;
+
+    # Declare an option for the port such that the type is checked and this option
+    # is shown in the manual.
+    options.port = lib.mkOption {
+      type = lib.types.port;
+      default = 8080;
+      description = ''
+        Which port this service should listen on.
+      '';
+    };
+
+  };
+  default = {};
+  description = ''
+    Configuration for Foo, see
+    &lt;link xlink:href="https://example.com/docs/foo"/&gt;
+    for supported values.
+  '';
+};
+</programlisting>
+     </example>
+    </para>
+   </section>
+ </section>
+
+</section>
diff --git a/nixos/doc/manual/development/writing-modules.xml b/nixos/doc/manual/development/writing-modules.xml
index bbf793bb0be98..d244356dbed19 100644
--- a/nixos/doc/manual/development/writing-modules.xml
+++ b/nixos/doc/manual/development/writing-modules.xml
@@ -183,4 +183,6 @@ in {
  <xi:include href="meta-attributes.xml" />
  <xi:include href="importing-modules.xml" />
  <xi:include href="replace-modules.xml" />
+ <xi:include href="freeform-modules.xml" />
+ <xi:include href="settings-options.xml" />
 </chapter>
diff --git a/nixos/doc/manual/development/writing-nixos-tests.xml b/nixos/doc/manual/development/writing-nixos-tests.xml
index 150bea8c2d86c..cab4c067e0d35 100644
--- a/nixos/doc/manual/development/writing-nixos-tests.xml
+++ b/nixos/doc/manual/development/writing-nixos-tests.xml
@@ -43,7 +43,7 @@ xlink:href="https://github.com/NixOS/nixpkgs/blob/master/nixos/tests/login.nix">
   console, whether device ownership is correctly maintained when switching
   between consoles, and so on. On the other hand,
   <filename
-xlink:href="https://github.com/NixOS/nixpkgs/blob/master/nixos/tests/nfs.nix">nfs.nix</filename>,
+xlink:href="https://github.com/NixOS/nixpkgs/blob/master/nixos/tests/nfs/simple.nix">nfs/simple.nix</filename>,
   which tests NFS client and server functionality in the Linux kernel
   (including whether locks are maintained across server crashes), requires
   three machines: a server and two clients.
@@ -216,12 +216,12 @@ start_all()
    </varlistentry>
    <varlistentry>
     <term>
-     <methodname>send_keys</methodname>
+     <methodname>send_key</methodname>
     </term>
     <listitem>
      <para>
       Simulate pressing keys on the virtual keyboard, e.g.,
-      <literal>send_keys("ctrl-alt-delete")</literal>.
+      <literal>send_key("ctrl-alt-delete")</literal>.
      </para>
     </listitem>
    </varlistentry>
@@ -232,7 +232,7 @@ start_all()
     <listitem>
      <para>
       Simulate typing a sequence of characters on the virtual keyboard, e.g.,
-      <literal>send_keys("foobar\n")</literal> will type the string
+      <literal>send_chars("foobar\n")</literal> will type the string
       <literal>foobar</literal> followed by the Enter key.
      </para>
     </listitem>
@@ -362,6 +362,18 @@ start_all()
    </varlistentry>
    <varlistentry>
     <term>
+     <methodname>wait_for_console_text</methodname>
+    </term>
+    <listitem>
+     <para>
+      Wait until the supplied regular expressions match a line of the serial
+      console output. This method is useful when OCR is not possibile or
+      accurate enough.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
      <methodname>wait_for_window</methodname>
     </term>
     <listitem>
@@ -378,7 +390,7 @@ start_all()
     <listitem>
      <para>
       Copies a file from host to machine, e.g.,
-      <literal>copy_file_from_host("myfile", "/etc/my/important/file")</literal>.
+      <literal>copy_from_host("myfile", "/etc/my/important/file")</literal>.
      </para>
      <para>
       The first argument is the file on the host. The file needs to be
diff --git a/nixos/doc/manual/installation/changing-config.xml b/nixos/doc/manual/installation/changing-config.xml
index 48193d986ab7c..4288806d5eb21 100644
--- a/nixos/doc/manual/installation/changing-config.xml
+++ b/nixos/doc/manual/installation/changing-config.xml
@@ -78,7 +78,7 @@
   <literal>mutableUsers = false</literal>. Another way is to temporarily add
   the following to your configuration:
 <screen>
-<link linkend="opt-users.users._name__.initialHashedPassword">users.users.your-user.initialHashedPassword</link> = "test";
+<link linkend="opt-users.users._name_.initialHashedPassword">users.users.your-user.initialHashedPassword</link> = "test";
 </screen>
   <emphasis>Important:</emphasis> delete the $hostname.qcow2 file if you have
   started the virtual machine at least once without the right users, otherwise
diff --git a/nixos/doc/manual/installation/installing-from-other-distro.xml b/nixos/doc/manual/installation/installing-from-other-distro.xml
index 45d68f8787f1b..d2d1245c57ac9 100644
--- a/nixos/doc/manual/installation/installing-from-other-distro.xml
+++ b/nixos/doc/manual/installation/installing-from-other-distro.xml
@@ -211,7 +211,7 @@ nixpkgs https://nixos.org/channels/nixpkgs-unstable</screen>
     use <literal>sudo</literal>)
    </para>
 <programlisting>
-<link linkend="opt-users.users._name__.initialHashedPassword">users.users.root.initialHashedPassword</link> = "";
+<link linkend="opt-users.users._name_.initialHashedPassword">users.users.root.initialHashedPassword</link> = "";
 </programlisting>
   </listitem>
   <listitem>
diff --git a/nixos/doc/manual/installation/installing-pxe.xml b/nixos/doc/manual/installation/installing-pxe.xml
index 94199e5e028db..ea88fbdad7e29 100644
--- a/nixos/doc/manual/installation/installing-pxe.xml
+++ b/nixos/doc/manual/installation/installing-pxe.xml
@@ -16,7 +16,7 @@
  </para>
 
 <programlisting>
-nix-build -A netboot nixos/release.nix
+nix-build -A netboot.x86_64-linux nixos/release.nix
 </programlisting>
 
  <para>
diff --git a/nixos/doc/manual/installation/installing-virtualbox-guest.xml b/nixos/doc/manual/installation/installing-virtualbox-guest.xml
index 0ba909fa953fb..1cffeed480790 100644
--- a/nixos/doc/manual/installation/installing-virtualbox-guest.xml
+++ b/nixos/doc/manual/installation/installing-virtualbox-guest.xml
@@ -49,7 +49,7 @@
   </listitem>
   <listitem>
    <para>
-    Click on Settings / Display / Screen and select VBoxVGA as Graphics Controller
+    Click on Settings / Display / Screen and select VMSVGA as Graphics Controller
    </para>
   </listitem>
   <listitem>
diff --git a/nixos/doc/manual/installation/installing.xml b/nixos/doc/manual/installation/installing.xml
index 673df8f2e4c4e..6df1d83034838 100644
--- a/nixos/doc/manual/installation/installing.xml
+++ b/nixos/doc/manual/installation/installing.xml
@@ -42,7 +42,7 @@
   </para>
 
   <para>
-   If the text is too small to be legible, try <command>setfont ter-132n</command>
+   If the text is too small to be legible, try <command>setfont ter-v32n</command>
    to increase the font size.
   </para>
 
@@ -70,9 +70,13 @@
 
    <para>
     If you would like to continue the installation from a different machine you
-    need to activate the SSH daemon via <command>systemctl start
-    sshd</command>. You then must set a password for either <literal>root</literal> or
-    <literal>nixos</literal> with <command>passwd</command> to be able to login.
+    can use activated SSH daemon. You need to copy your ssh key to either
+    <literal>/home/nixos/.ssh/authorized_keys</literal> or
+    <literal>/root/.ssh/authorized_keys</literal> (Tip: For installers with a
+    modifiable filesystem such as the sd-card installer image a key can be manually
+    placed by mounting the image on a different machine). Alternatively you must set
+    a password for either <literal>root</literal> or <literal>nixos</literal> with
+    <command>passwd</command> to be able to login.
    </para>
   </section>
  </section>
@@ -146,7 +150,7 @@
        partition. It uses the initially reserved 512MiB at the start of the
        disk.
 <screen language="commands"><prompt># </prompt>parted /dev/sda -- mkpart ESP fat32 1MiB 512MiB
-<prompt># </prompt>parted /dev/sda -- set 3 boot on</screen>
+<prompt># </prompt>parted /dev/sda -- set 3 esp on</screen>
       </para>
      </listitem>
     </orderedlist>
@@ -513,7 +517,7 @@ Retype new UNIX password: ***</screen>
 <prompt># </prompt>parted /dev/sda -- mkpart primary 512MiB -8GiB
 <prompt># </prompt>parted /dev/sda -- mkpart primary linux-swap -8GiB 100%
 <prompt># </prompt>parted /dev/sda -- mkpart ESP fat32 1MiB 512MiB
-<prompt># </prompt>parted /dev/sda -- set 3 boot on</screen>
+<prompt># </prompt>parted /dev/sda -- set 3 esp on</screen>
   </example>
 
   <example xml:id="ex-install-sequence">
@@ -550,7 +554,7 @@ Retype new UNIX password: ***</screen>
   # Note: setting fileSystems is generally not
   # necessary, since nixos-generate-config figures them out
   # automatically in hardware-configuration.nix.
-  #<link linkend="opt-fileSystems._name__.device">fileSystems."/".device</link> = "/dev/disk/by-label/nixos";
+  #<link linkend="opt-fileSystems._name_.device">fileSystems."/".device</link> = "/dev/disk/by-label/nixos";
 
   # Enable the OpenSSH server.
   services.sshd.enable = true;
diff --git a/nixos/doc/manual/man-nixos-build-vms.xml b/nixos/doc/manual/man-nixos-build-vms.xml
index d114261f53bef..fa7c8c0c6d799 100644
--- a/nixos/doc/manual/man-nixos-build-vms.xml
+++ b/nixos/doc/manual/man-nixos-build-vms.xml
@@ -13,15 +13,15 @@
  </refnamediv>
  <refsynopsisdiv>
   <cmdsynopsis>
-   <command>nixos-build-vms</command> 
+   <command>nixos-build-vms</command>
    <arg>
     <option>--show-trace</option>
    </arg>
-    
+
    <arg>
     <option>--no-out-link</option>
    </arg>
-    
+
    <arg>
     <option>--help</option>
   </arg>
diff --git a/nixos/doc/manual/man-nixos-enter.xml b/nixos/doc/manual/man-nixos-enter.xml
index fe560d3efdd8e..f533d66099d39 100644
--- a/nixos/doc/manual/man-nixos-enter.xml
+++ b/nixos/doc/manual/man-nixos-enter.xml
@@ -13,21 +13,21 @@
  </refnamediv>
  <refsynopsisdiv>
   <cmdsynopsis>
-   <command>nixos-enter</command> 
+   <command>nixos-enter</command>
    <arg>
     <arg choice='plain'>
      <option>--root</option>
     </arg>
      <replaceable>root</replaceable>
    </arg>
-    
+
    <arg>
     <arg choice='plain'>
      <option>--system</option>
     </arg>
      <replaceable>system</replaceable>
    </arg>
-    
+
    <arg>
     <arg choice='plain'>
      <option>-c</option>
@@ -40,13 +40,13 @@
      <option>--silent</option>
     </arg>
    </arg>
-    
+
    <arg>
     <arg choice='plain'>
      <option>--help</option>
     </arg>
    </arg>
-    
+
    <arg>
     <arg choice='plain'>
      <option>--</option>
@@ -136,7 +136,7 @@
    <filename>/mnt</filename>:
   </para>
 <screen>
-# nixos-enter /mnt
+# nixos-enter --root /mnt
 </screen>
   <para>
    Run a shell command:
diff --git a/nixos/doc/manual/man-nixos-install.xml b/nixos/doc/manual/man-nixos-install.xml
index 84849282e9abd..b205e23096875 100644
--- a/nixos/doc/manual/man-nixos-install.xml
+++ b/nixos/doc/manual/man-nixos-install.xml
@@ -46,6 +46,10 @@
    </arg>
 
    <arg>
+    <option>--flake</option> <replaceable>flake-uri</replaceable>
+   </arg>
+
+   <arg>
      <arg choice='plain'>
        <option>--channel</option>
      </arg>
@@ -200,6 +204,18 @@
     </listitem>
    </varlistentry>
    <varlistentry>
+    <term>
+     <option>--flake</option> <replaceable>flake-uri</replaceable>#<replaceable>name</replaceable>
+    </term>
+    <listitem>
+     <para>
+      Build the NixOS system from the specified flake.
+      The flake must contain an output named
+      <literal>nixosConfigurations.<replaceable>name</replaceable></literal>.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
      <term>
        <option>--channel</option>
      </term>
diff --git a/nixos/doc/manual/man-nixos-rebuild.xml b/nixos/doc/manual/man-nixos-rebuild.xml
index f4f663b84f056..7dab5c69dfb5f 100644
--- a/nixos/doc/manual/man-nixos-rebuild.xml
+++ b/nixos/doc/manual/man-nixos-rebuild.xml
@@ -315,7 +315,7 @@
        switch</command>), because the hardware and boot loader configuration in
        the VM are different. The boot loader is installed on an automatically
        generated virtual disk containing a <filename>/boot</filename>
-       partition, which is mounted read-only in the VM.
+       partition.
       </para>
      </listitem>
     </varlistentry>
@@ -521,7 +521,7 @@
 
    <varlistentry>
     <term>
-     <option>--flake</option> <replaceable>flake-uri</replaceable>[<replaceable>name</replaceable>]
+     <option>--flake</option> <replaceable>flake-uri</replaceable><optional>#<replaceable>name</replaceable></optional>
     </term>
     <listitem>
      <para>
diff --git a/nixos/doc/manual/release-notes/release-notes.xml b/nixos/doc/manual/release-notes/release-notes.xml
index e2913b8a5353d..bf18457c2b385 100644
--- a/nixos/doc/manual/release-notes/release-notes.xml
+++ b/nixos/doc/manual/release-notes/release-notes.xml
@@ -8,6 +8,7 @@
   This section lists the release notes for each stable version of NixOS and
   current unstable revision.
  </para>
+ <xi:include href="rl-2103.xml" />
  <xi:include href="rl-2009.xml" />
  <xi:include href="rl-2003.xml" />
  <xi:include href="rl-1909.xml" />
diff --git a/nixos/doc/manual/release-notes/rl-2003.xml b/nixos/doc/manual/release-notes/rl-2003.xml
index 393a9286ca4f5..87f1228561949 100644
--- a/nixos/doc/manual/release-notes/rl-2003.xml
+++ b/nixos/doc/manual/release-notes/rl-2003.xml
@@ -792,11 +792,11 @@ users.users.me =
      The <option>services.xserver.displayManager.auto</option> module has been removed.
      It was only intended for use in internal NixOS tests, and gave the false impression
      of it being a special display manager when it's actually LightDM.
-     Please use the <xref linkend="opt-services.xserver.displayManager.lightdm.autoLogin"/> options instead,
+     Please use the <option>services.xserver.displayManager.lightdm.autoLogin</option> options instead,
      or any other display manager in NixOS as they all support auto-login. If you used this module specifically
      because it permitted root auto-login you can override the lightdm-autologin pam module like:
 <programlisting>
-<link xlink:href="#opt-security.pam.services._name__.text">security.pam.services.lightdm-autologin.text</link> = lib.mkForce ''
+<link xlink:href="#opt-security.pam.services._name_.text">security.pam.services.lightdm-autologin.text</link> = lib.mkForce ''
     auth     requisite pam_nologin.so
     auth     required  pam_succeed_if.so quiet
     auth     required  pam_permit.so
diff --git a/nixos/doc/manual/release-notes/rl-2009.xml b/nixos/doc/manual/release-notes/rl-2009.xml
index 9bbbecc05692a..511276bcaab31 100644
--- a/nixos/doc/manual/release-notes/rl-2009.xml
+++ b/nixos/doc/manual/release-notes/rl-2009.xml
@@ -27,6 +27,18 @@
     <para>GNOME desktop environment was upgraded to 3.36, see its <link xlink:href="https://help.gnome.org/misc/release-notes/3.36/">release notes</link>.</para>
    </listitem>
    <listitem>
+     <para>
+     The Cinnamon desktop environment (v4.6) has been added. <varname>services.xserver.desktopManager.cinnamon.enable = true;</varname> to try it out!
+     Remember that, with any new feature it's possible you could run into issues, so please send all support requests to <link xlink:href="https://github.com/NixOS/nixpkgs/issues">github.com/NixOS/nixpkgs</link> to notify the maintainers.
+     </para>
+   </listitem>
+   <listitem>
+    <para>
+      Quickly configure a complete, private, self-hosted video
+      conferencing solution with the new Jitsi Meet module.
+    </para>
+   </listitem>
+   <listitem>
     <para>
     <package>maxx</package> package removed along with <varname>services.xserver.desktopManager.maxx</varname> module.
     Please migrate to <package>cdesktopenv</package> and <varname>services.xserver.desktopManager.cde</varname> module.
@@ -44,6 +56,11 @@
    </listitem>
    <listitem>
     <para>
+     PHP 7.2 is no longer supported due to upstream not supporting this version for the entire lifecycle of the 20.09 release.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
      Python 3 now defaults to Python 3.8 instead of 3.7.
     </para>
    </listitem>
@@ -109,6 +126,105 @@ systemd.services.mysql.serviceConfig.ProtectHome = lib.mkForce "read-only";
 systemd.services.mysql.serviceConfig.ReadWritePaths = [ "/var/data" ];
 </programlisting>
     </para>
+    <para>
+      The MySQL service no longer runs its <literal>systemd</literal> service startup script as <literal>root</literal> anymore. A dedicated non <literal>root</literal>
+      super user account is required for operation. This means users with an existing MySQL or MariaDB database server are required to run the following SQL statements
+      as a super admin user before upgrading:
+<programlisting>
+CREATE USER IF NOT EXISTS 'mysql'@'localhost' identified with unix_socket;
+GRANT ALL PRIVILEGES ON *.* TO 'mysql'@'localhost' WITH GRANT OPTION;
+</programlisting>
+      If you use MySQL instead of MariaDB please replace <literal>unix_socket</literal> with <literal>auth_socket</literal>. If you have changed the value of <xref linkend="opt-services.mysql.user"/>
+      from the default of <literal>mysql</literal> to a different user please change <literal>'mysql'@'localhost'</literal> to the corresponding user instead.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+      The new option <link linkend="opt-documentation.man.generateCaches">documentation.man.generateCaches</link>
+      has been added to automatically generate the <literal>man-db</literal> caches, which are needed by utilities
+      like <command>whatis</command> and <command>apropos</command>. The caches are generated during the build of
+      the NixOS configuration: since this can be expensive when a large number of packages are installed, the
+      feature is disabled by default.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     <varname>services.postfix.sslCACert</varname> was replaced by <varname>services.postfix.tlsTrustedAuthorities</varname> which now defaults to system certificate authorities.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+      Subordinate GID and UID mappings are now set up automatically for all normal users.
+      This will make container tools like Podman work as non-root users out of the box.
+    </para>
+   </listitem>
+   <listitem>
+     <para>
+       The various documented workarounds to use steam have been converted to a module. <varname>programs.steam.enable</varname> enables steam, controller support and the workarounds.
+     </para>
+   </listitem>
+   <listitem>
+     <para>
+       Support for built-in LCDs in various pieces of Logitech hardware (keyboards and USB speakers). <varname>hardware.logitech.lcd.enable</varname> enables support for all hardware supported by the g15daemon project.
+     </para>
+   </listitem>
+   <listitem>
+    <para>
+      Zabbix now defaults to 5.0, updated from 4.4. Please carefully read through
+      <link xlink:href="https://www.zabbix.com/documentation/current/manual/installation/upgrade/sources">the upgrade guide</link>
+      and apply any changes required. Be sure to take special note of the section on
+      <link xlink:href="https://www.zabbix.com/documentation/current/manual/installation/upgrade_notes_500#enabling_extended_range_of_numeric_float_values">enabling extended range of numeric (float) values</link>
+      as you will need to apply this database migration manually.
+    </para>
+    <para>
+      If you are using Zabbix Server with a MySQL or MariaDB database you should note that using a character set of <literal>utf8</literal> and a collate of <literal>utf8_bin</literal> has become mandatory with
+      this release. See the upstream <link xlink:href="https://support.zabbix.com/browse/ZBX-17357">issue</link> for further discussion. Before upgrading you should check the character set and collation used by
+      your database and ensure they are correct:
+<programlisting>
+  SELECT
+    default_character_set_name,
+    default_collation_name
+  FROM
+    information_schema.schemata
+  WHERE
+    schema_name = 'zabbix';
+</programlisting>
+      If these values are not correct you should take a backup of your database and convert the character set and collation as required. Here is an
+      <link xlink:href="https://www.zabbix.com/forum/zabbix-help/396573-reinstall-after-upgrade?p=396891#post396891">example</link> of how to do so, taken from
+      the Zabbix forums:
+<programlisting>
+  ALTER DATABASE `zabbix` DEFAULT CHARACTER SET utf8 COLLATE utf8_bin;
+
+  -- the following will produce a list of SQL commands you should subsequently execute
+  SELECT CONCAT("ALTER TABLE ", TABLE_NAME," CONVERT TO CHARACTER SET utf8 COLLATE utf8_bin;") AS ExecuteTheString
+  FROM information_schema.`COLUMNS`
+  WHERE table_schema = "zabbix" AND COLLATION_NAME = "utf8_general_ci";
+</programlisting>
+    </para>
+   </listitem>
+   <listitem>
+     <para>
+      The NixOS module system now supports freeform modules as a mix between <literal>types.attrsOf</literal> and <literal>types.submodule</literal>. These allow you to explicitly declare a subset of options while still permitting definitions without an associated option. See <xref linkend='sec-freeform-modules'/> for how to use them.
+     </para>
+   </listitem>
+   <listitem>
+     <para>
+       The GRUB module gained support for basic password protection, which
+       allows to restrict non-default entries in the boot menu to one or more
+       users. The users and passwords are defined via the option
+       <option>boot.loader.grub.users</option>.
+       Note: Password support is only avaiable in GRUB version 2.
+     </para>
+   </listitem>
+   <listitem>
+     <para>
+       Following its deprecation in 20.03, the Perl NixOS test driver has been removed.
+       All remaining tests have been ported to the Python test framework.
+       Code outside nixpkgs using <filename>make-test.nix</filename> or
+       <filename>testing.nix</filename> needs to be ported to
+       <filename>make-test-python.nix</filename> and
+       <filename>testing-python.nix</filename> respectively.
+     </para>
    </listitem>
   </itemizedlist>
  </section>
@@ -129,6 +245,11 @@ systemd.services.mysql.serviceConfig.ReadWritePaths = [ "/var/data" ];
     <para>
       There is a new <xref linkend="opt-security.doas.enable"/> module that provides <command>doas</command>, a lighter alternative to <command>sudo</command> with many of the same features.
     </para>
+  </listitem>
+  <listitem>
+    <para>
+      <link xlink:href="https://hercules-ci.com">Hercules CI</link> Agent is a specialized build agent for projects built with Nix. See the <link xlink:href="https://nixos.org/nixos/options.html#services.hercules-ci-agent">options</link> and <link xlink:href="https://docs.hercules-ci.com/hercules-ci/getting-started/#deploy-agent">setup</link>.
+    </para>
    </listitem>
   </itemizedlist>
 
@@ -153,12 +274,10 @@ systemd.services.mysql.serviceConfig.ReadWritePaths = [ "/var/data" ];
      in the source tree for downloaded modules instead of using go's <link
      xlink:href="https://golang.org/cmd/go/#hdr-Module_proxy_protocol">module
      proxy protocol</link>. This storage format is simpler and therefore less
-     likekly to break with future versions of go. As a result
+     likely to break with future versions of go. As a result
      <literal>buildGoModule</literal> switched from
      <literal>modSha256</literal> to the <literal>vendorSha256</literal>
-     attribute to pin fetched version data. <literal>buildGoModule</literal>
-     still accepts <literal>modSha256</literal> with a warning, but support will
-     be removed in the next release.
+     attribute to pin fetched version data.
     </para>
    </listitem>
    <listitem>
@@ -167,7 +286,7 @@ systemd.services.mysql.serviceConfig.ReadWritePaths = [ "/var/data" ];
      <link xlink:href="https://grafana.com/docs/grafana/latest/guides/whats-new-in-v6-4/">deprecated in Grafana</link>
      and the <package>phantomjs</package> project is
      <link xlink:href="https://github.com/ariya/phantomjs/issues/15344#issue-302015362">currently unmaintained</link>.
-     It can still be enabled by providing <literal>phantomJsSupport = true</literal> to the package instanciation:
+     It can still be enabled by providing <literal>phantomJsSupport = true</literal> to the package instantiation:
 <programlisting>{
   services.grafana.package = pkgs.grafana.overrideAttrs (oldAttrs: rec {
     phantomJsSupport = false;
@@ -179,7 +298,7 @@ systemd.services.mysql.serviceConfig.ReadWritePaths = [ "/var/data" ];
     <para>
       The <link linkend="opt-services.supybot.enable">supybot</link> module now uses <literal>/var/lib/supybot</literal>
       as its default <link linkend="opt-services.supybot.stateDir">stateDir</link> path if <literal>stateVersion</literal>
-      is 20.09 or higher. It also enables number of
+      is 20.09 or higher. It also enables a number of
       <link xlink:href="https://www.freedesktop.org/software/systemd/man/systemd.exec.html#Sandboxing">systemd sandboxing options</link>
       which may possibly interfere with some plugins. If this is the case you can disable the options through attributes in
       <option>systemd.services.supybot.serviceConfig</option>.
@@ -288,6 +407,20 @@ php.override {
      </para>
    </listitem>
    <listitem>
+    <para>
+     The ACME module has been overhauled for simplicity and maintainability.
+     Cert generation now implicitly uses the <literal>acme</literal>
+     user, and the <literal>security.acme.certs._name_.user</literal> option
+     has been removed. Instead, certificate access from other services is now
+     managed through group permissions. The module no longer runs lego
+     twice under certain conditions, and will correctly renew certificates if
+     their configuration is changed. Services which reload nginx and httpd after
+     certificate renewal are now properly configured too so you no longer have
+     to do this manually if you are using HTTPS enabled virtual hosts. A mechanism
+     for regenerating certs on demand has also been added and documented.
+    </para>
+   </listitem>
+   <listitem>
      <para>
       Gollum received a major update to version 5.x and you may have to change
       some links in your wiki when migrating from gollum 4.x. More information
@@ -306,8 +439,8 @@ php.override {
    </listitem>
    <listitem>
      <para>
-       Add option <literal>services.nginx.enableSandbox</literal> to starting Nginx web server with additional sandbox/hardening options.
-       By default, write access to <literal>services.nginx.stateDir</literal> is allowed. To allow writing to other folders,
+       Nginx web server now starting with additional sandbox/hardening options. By default, write access
+       to <literal>services.nginx.stateDir</literal> is allowed. To allow writing to other folders,
        use <literal>systemd.services.nginx.serviceConfig.ReadWritePaths</literal>
        <programlisting>
 systemd.services.nginx.serviceConfig.ReadWritePaths = [ "/var/www" ];
@@ -490,6 +623,217 @@ systemd.services.nginx.serviceConfig.ReadWritePaths = [ "/var/www" ];
      <link xlink:href="https://github.com/NixOS/nixpkgs/issues/89205">#89205</link>.
     </para>
    </listitem>
+   <listitem>
+    <para>
+     In the <literal>resilio</literal> module, <xref linkend="opt-services.resilio.httpListenAddr"/> has been changed to listen to <literal>[::1]</literal> instead of <literal>0.0.0.0</literal>.
+     </para>
+   </listitem>
+   <listitem>
+    <para>
+     Users of <link xlink:href="http://openafs.org">OpenAFS 1.6</link> must
+     upgrade their services to OpenAFS 1.8! In this release, the OpenAFS package
+     version 1.6.24 is marked broken but can be used during transition to
+     OpenAFS 1.8.x. Use the options
+     <option>services.openafsClient.packages.module</option>,
+     <option>services.openafsClient.packages.programs</option> and
+     <option>services.openafsServer.package</option> to select a different
+     OpenAFS package. OpenAFS 1.6 will be removed in the next release. The
+     package <literal>openafs</literal> and the service options will then
+     silently point to the OpenAFS 1.8 release.
+    </para>
+    <para>
+     See also the OpenAFS <link
+     xlink:href="http://docs.openafs.org/AdminGuide/index.html">Administrator
+     Guide</link> for instructions. Beware of the following when updating
+     servers:
+     <itemizedlist>
+      <listitem>
+       <para>
+       The storage format of the server key has changed and the key must be converted before running the new release.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+       When updating multiple database servers, turn off the database servers
+       from the highest IP down to the lowest with resting periods in
+       between. Start up in reverse order. Do not concurrently run database
+       servers working with different OpenAFS releases!
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+       Update servers first, then clients.
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Radicale's default package has changed from 2.x to 3.x. An upgrade
+     checklist can be found
+     <link xlink:href="https://github.com/Kozea/Radicale/blob/3.0.x/NEWS.md#upgrade-checklist">here</link>.
+     You can use the newer version in the NixOS service by setting the
+     <literal>package</literal> to <literal>radicale3</literal>, which is done
+     automatically if <literal>stateVersion</literal> is 20.09 or higher.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+      <literal>udpt</literal> experienced a complete rewrite from C++ to rust. The configuration format changed from ini to toml.
+      The new configuration documentation can be found at
+      <link xlink:href="https://naim94a.github.io/udpt/config.html">the official website</link> and example
+      configuration is packaged in <literal>${udpt}/share/udpt/udpt.toml</literal>.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     We now have a unified <xref linkend="opt-services.xserver.displayManager.autoLogin"/> option interface
+     to be used for every display-manager in NixOS.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The <literal>bitcoind</literal> module has changed to multi-instance, using submodules.
+     Therefore, it is now mandatory to name each instance.
+     To use this new multi-instance config with an existing bitcoind data directory and user,
+     you have to adjust the original config, e.g.:
+<programlisting>
+  services.bitcoind = {
+    enable = true;
+    extraConfig = "...";
+    ...
+  };
+</programlisting>
+     To something similar:
+<programlisting>
+  services.bitcoind.mainnet = {
+    enable = true;
+    dataDir = "/var/lib/bitcoind";
+    user = "bitcoin";
+    extraConfig = "...";
+    ...
+  };
+</programlisting>
+     The key settings are:
+     <itemizedlist>
+      <listitem>
+       <para>
+        <literal>dataDir</literal> - to continue using the same data directory.
+       </para>
+      </listitem>
+      <listitem>
+       <para>
+        <literal>user</literal> - to continue using the same user so that bitcoind maintains access to its files.
+       </para>
+      </listitem>
+     </itemizedlist>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+      Graylog introduced a change in the LDAP server certificate validation behaviour for version 3.3.3 which might break existing setups.
+      When updating Graylog from a version before 3.3.3 make sure to check the Graylog <link xlink:href="https://www.graylog.org/post/announcing-graylog-v3-3-3">release info</link> for information on how to avoid the issue.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The <literal>dokuwiki</literal> module has changed to multi-instance, using submodules.
+     Therefore, it is now mandatory to name each instance. Moreover, forcing SSL by default has been dropped, so
+     <literal>nginx.forceSSL</literal> and <literal>nginx.enableACME</literal> are no longer set to <literal>true</literal>.
+     To continue using your service with the original SSL settings, you have to adjust the original config, e.g.:
+<programlisting>
+services.dokuwiki = {
+  enable = true;
+  ...
+};
+</programlisting>
+     To something similar:
+<programlisting>
+services.dokuwiki."mywiki" = {
+  enable = true;
+  nginx = {
+    forceSSL = true;
+    enableACME = true;
+  };
+  ...
+};
+</programlisting>
+     The base package has also been upgraded to the 2020-07-29 "Hogfather" release. Plugins might be incompatible or require upgrading.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+      The <xref linkend="opt-services.postgresql.dataDir"/> option is now set to <literal>"/var/lib/postgresql/${cfg.package.psqlSchema}"</literal> regardless of your
+      <xref linkend="opt-system.stateVersion"/>. Users with an existing postgresql install that have a <xref linkend="opt-system.stateVersion"/> of <literal>17.03</literal> or below
+      should double check what the value of their <xref linkend="opt-services.postgresql.dataDir"/> option is (<literal>/var/db/postgresql</literal>) and then explicitly
+      set this value to maintain compatibility:
+<programlisting>
+services.postgresql.dataDir = "/var/db/postgresql";
+</programlisting>
+    </para>
+    <para>
+     The postgresql module now expects there to be a database super user account called <literal>postgres</literal> regardless of your <xref linkend="opt-system.stateVersion"/>. Users
+     with an existing postgresql install that have a <xref linkend="opt-system.stateVersion"/> of <literal>17.03</literal> or below should run the following SQL statements as a
+     database super admin user before upgrading:
+<programlisting>
+CREATE ROLE postgres LOGIN SUPERUSER;
+</programlisting>
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The USBGuard module now removes options and instead hardcodes values for <literal>IPCAccessControlFiles</literal>, <literal>ruleFiles</literal>, and <literal>auditFilePath</literal>. Audit logs can be found in the journal.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The NixOS module system now evaluates option definitions more strictly, allowing it to detect a larger set of problems.
+     As a result, what previously evaluated may not do so anymore.
+     See <link xlink:href="https://github.com/NixOS/nixpkgs/pull/82743#issuecomment-674520472">the PR that changed this</link> for more info.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     For NixOS configuration options, the type <literal>loaOf</literal>, after
+     its initial deprecation in release 20.03, has been removed. In NixOS and
+     Nixpkgs options using this type have been converted to <literal>attrsOf</literal>.
+     For more information on this change have look at these links:
+     <link xlink:href="https://github.com/NixOS/nixpkgs/issues/1800">issue #1800</link>,
+     <link xlink:href="https://github.com/NixOS/nixpkgs/pull/63103">PR #63103</link>.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+      <literal>config.systemd.services.${name}.path</literal> now returns a list of paths instead of a colon-separated string.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Caddy module now uses Caddy v2 by default. Caddy v1 can still be used by setting
+     <xref linkend="opt-services.caddy.package"/> to <literal>pkgs.caddy1</literal>.
+    </para>
+    <para>
+     New option <xref linkend="opt-services.caddy.adapter"/> has been added.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The <link linkend="opt-services.jellyfin.enable">jellyfin</link> module will use and stay on the Jellyfin version <literal>10.5.5</literal>
+     if <literal>stateVersion</literal> is lower than <literal>20.09</literal>. This is because significant changes were made to the database schema,
+     and it is highly recommended to backup your instance before upgrading. After making your backup, you can upgrade to the latest version either by
+     setting your <literal>stateVersion</literal> to <literal>20.09</literal> or higher, or set the <option>services.jellyfin.package</option> to
+     <literal>pkgs.jellyfin</literal>. If you do not wish to upgrade Jellyfin, but want to change your <literal>stateVersion</literal>, you can set
+     the value of <option>services.jellyfin.package</option> to <literal>pkgs.jellyfin_10_5</literal>.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The <literal>security.rngd</literal> service is now disabled by default.
+     This choice was made because there's krngd in the linux kernel space making it (for most usecases)
+     functionally redundent.
+    </para>
+   </listitem>
   </itemizedlist>
  </section>
 
@@ -518,6 +862,17 @@ systemd.services.nginx.serviceConfig.ReadWritePaths = [ "/var/www" ];
      of the default <literal>out</literal> output anymore - if you relied on the
      <literal>notmuch-emacs-mua</literal> binary or the emacs lisp files, access them via
      the <literal>notmuch.emacs</literal> output.
+
+     Device tree overlay support was improved in
+     <link xlink:href="https://github.com/NixOS/nixpkgs/pull/79370">#79370</link>
+     and now uses <xref linkend="opt-hardware.deviceTree.kernelPackage"/>
+     instead of <option>hardware.deviceTree.base</option>.
+
+     <xref linkend="opt-hardware.deviceTree.overlays"/> configuration was
+     extended to support <literal>.dts</literal> files with symbols.
+
+     Device trees can now be filtered by setting
+     <xref linkend="opt-hardware.deviceTree.filter"/> option.
     </para>
    </listitem>
    <listitem>
@@ -527,6 +882,11 @@ systemd.services.nginx.serviceConfig.ReadWritePaths = [ "/var/www" ];
    </listitem>
    <listitem>
     <para>
+     <literal>buildGoModule</literal> <literal>doCheck</literal> now defaults to <literal>true</literal>.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
      Packages built using <literal>buildRustPackage</literal> now use <literal>release</literal>
      mode for the <literal>checkPhase</literal> by default.
     </para>
@@ -555,6 +915,12 @@ systemd.services.nginx.serviceConfig.ReadWritePaths = [ "/var/www" ];
    </listitem>
    <listitem>
     <para>
+    The installer now enables sshd by default. This improves installation on headless machines especially ARM single-board-computer.
+    To login through ssh, either a password or an ssh key must be set for the root user or the nixos user.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
      The scripted networking system now uses <literal>.link</literal> files in
      <literal>/etc/systemd/network</literal> to configure mac address and link MTU,
      instead of the sometimes buggy <literal>network-link-*</literal> units, which
@@ -584,6 +950,37 @@ systemd.services.nginx.serviceConfig.ReadWritePaths = [ "/var/www" ];
    </listitem>
    <listitem>
     <para>
+     The <literal>services.transmission</literal> module
+     was enhanced with the new options:
+     <xref linkend="opt-services.transmission.credentialsFile"/>,
+     <xref linkend="opt-services.transmission.openFirewall"/>,
+     and <xref linkend="opt-services.transmission.performanceNetParameters"/>.
+    </para>
+    <para>
+     <literal>transmission-daemon</literal> is now started with additional systemd sandbox/hardening options for better security.
+     Please <link xlink:href="https://github.com/NixOS/nixpkgs/issues">report</link>
+     any use case where this is not working well.
+     In particular, the <literal>RootDirectory</literal> option newly set
+     forbids uploading or downloading a torrent outside of the default directory
+     configured at <link linkend="opt-services.transmission.settings">settings.download-dir</link>.
+     If you really need Transmission to access other directories,
+     you must include those directories into the <literal>BindPaths</literal> of the service:
+<programlisting>
+systemd.services.transmission.serviceConfig.BindPaths = [ "/path/to/alternative/download-dir" ];
+</programlisting>
+    </para>
+    <para>
+     Also, connection to the RPC (Remote Procedure Call) of <literal>transmission-daemon</literal>
+     is now only available on the local network interface by default.
+     Use:
+<programlisting>
+services.transmission.settings.rpc-bind-address = "0.0.0.0";
+</programlisting>
+     to get the previous behavior of listening on all network interfaces.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
      With this release <literal>systemd-networkd</literal> (when enabled through <xref linkend="opt-networking.useNetworkd"/>)
      has it's netlink socket created through a <literal>systemd.socket</literal> unit. This gives us control over
      socket buffer sizes and other parameters. For larger setups where networkd has to create a lot of (virtual)
@@ -642,6 +1039,120 @@ systemd.services.nginx.serviceConfig.ReadWritePaths = [ "/var/www" ];
       <package>netbeans</package> was upgraded to 12.0 and now defaults to OpenJDK 11. This might cause problems if your projects depend on packages that were removed in Java 11.
     </para>
    </listitem>
+   <listitem>
+    <para>
+     <package>nextcloud</package> has been updated to <link xlink:href="https://nextcloud.com/blog/nextcloud-hub-brings-productivity-to-home-office/">v19</link>.
+    </para>
+    <para>
+     If you have an existing installation, please make sure that you're on
+     <package>nextcloud18</package> before upgrading to <package>nextcloud19</package>
+     since Nextcloud doesn't support upgrades across multiple major versions.
+    </para>
+     <para>
+       The <literal>nixos-run-vms</literal> script now deletes the
+       previous run machines states on test startup. You can use the
+       <literal>--keep-vm-state</literal> flag to match the previous
+       behaviour and keep the same VM state between different test runs.
+     </para>
+   </listitem>
+   <listitem>
+    <para>
+     The <link linkend="opt-nix.buildMachines">nix.buildMachines</link> option is now type-checked.
+     There are no functional changes, however this may require updating some configurations to use correct types for all attributes.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     The <literal>fontconfig</literal> module stopped generating fontconfig 2.10.x config and cache.
+     Fontconfig 2.10.x was removed from Nixpkgs - it hasn't been used in any nixpkgs package anymore.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+     Nginx module <literal>nginxModules.fastcgi-cache-purge</literal> renamed to official name <literal>nginxModules.cache-purge</literal>.
+     Nginx module <literal>nginxModules.ngx_aws_auth</literal> renamed to official name <literal>nginxModules.aws-auth</literal>.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+      The option <option>defaultPackages</option> was added. It installs the packages <package>perl</package>, <package>rsync</package> and <package>strace</package> for now. They were added unconditionally to <option>systemPackages</option> before, but are not strictly necessary for a minimal NixOS install. You can set it to an empty list to have a more minimal system. Be aware that some functionality might still have an impure dependency on those packages, so things might break.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+      The <literal>undervolt</literal> option no longer needs to apply its
+      settings every 30s. If they still become undone, open an issue and restore
+      the previous behaviour using <literal>undervolt.useTimer</literal>.
+    </para>
+   </listitem>
+   <listitem>
+     <para>
+      Agda has been heavily reworked.
+      <itemizedlist>
+	<listitem>
+	  <para>
+	    <literal>agda.mkDerivation</literal> has been heavily changed and
+	    is now located at <package>agdaPackages.mkDerivation</package>.
+	  </para>
+	</listitem>
+	<listitem>
+	  <para>
+	    New top-level packages <package>agda</package> and
+	    <literal>agda.withPackages</literal> have been added, the second
+	    of which sets up agda with access to chosen libraries.
+	  </para>
+	</listitem>
+	<listitem>
+	  <para>
+	    All agda libraries now live under
+	    <literal>agdaPackages</literal>.
+	  </para>
+	</listitem>
+	<listitem>
+	  <para>
+	    Many broken libraries have been removed.
+	  </para>
+	</listitem>
+      </itemizedlist>
+      See the <link
+      xlink:href="https://nixos.org/nixpkgs/manual/#agda">new
+      documentation</link> for more information.
+    </para>
+   </listitem>
+   <listitem>
+    <para>
+      The <literal>deepin</literal> package set has been removed from
+      nixpkgs. It was a work in progress to package the
+      <link xlink:href="https://www.deepin.org/en/dde/">Deepin Desktop Environment (DDE)</link>,
+      including libraries, tools and applications, and it was still
+      missing a service to lauch the desktop environment. It has shown
+      to no longer be a feasible goal due to reasons discussed in
+      <link xlink:href="https://github.com/NixOS/nixpkgs/issues/94870">issue #94870</link>.
+      The package <literal>netease-cloud-music</literal> has also been
+      removed, as it depends on libraries from deepin.
+    </para>
+   </listitem>
+   <listitem>
+     <para>
+       The <literal>opendkim</literal> module now uses systemd sandboxing features
+       to limit the exposure of the system towards the opendkim service.
+     </para>
+   </listitem>
+  </itemizedlist>
+  <itemizedlist>
+   <listitem>
+    <para />
+    <para>
+        Kubernetes has been upgraded to 1.19.1, which also means that the
+        golang version to build it has been bumped to 1.15. This may have
+        consequences for your existing clusters and their certificates. Please
+        consider
+        <link xlink:href="https://relnotes.k8s.io/?markdown=93264">
+            the release notes for Kubernetes 1.19 carefully
+        </link>
+        before upgrading.
+    </para>
+   </listitem>
   </itemizedlist>
  </section>
 </section>
diff --git a/nixos/doc/manual/release-notes/rl-2103.xml b/nixos/doc/manual/release-notes/rl-2103.xml
new file mode 100644
index 0000000000000..eccf2b69dad93
--- /dev/null
+++ b/nixos/doc/manual/release-notes/rl-2103.xml
@@ -0,0 +1,80 @@
+<section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="sec-release-21.03">
+ <title>Release 21.03 (“Okapi”, 2021.03/??)</title>
+
+ <section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="sec-release-21.03-highlights">
+  <title>Highlights</title>
+
+  <para>
+   In addition to numerous new and upgraded packages, this release has the
+   following highlights:
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para>
+     Support is planned until the end of October 2021, handing over to 21.09.
+    </para>
+   </listitem>
+  </itemizedlist>
+ </section>
+
+ <section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="sec-release-21.03-new-services">
+  <title>New Services</title>
+
+  <para>
+   The following new services were added since the last release:
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para />
+   </listitem>
+  </itemizedlist>
+
+ </section>
+
+ <section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="sec-release-21.03-incompatibilities">
+  <title>Backward Incompatibilities</title>
+
+  <para>
+   When upgrading from a previous release, please be aware of the following
+   incompatible changes:
+  </para>
+
+  <itemizedlist>
+   <listitem>
+    <para />
+   </listitem>
+  </itemizedlist>
+ </section>
+
+ <section xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="sec-release-21.03-notable-changes">
+  <title>Other Notable Changes</title>
+
+  <itemizedlist>
+   <listitem>
+    <para />
+   </listitem>
+  </itemizedlist>
+ </section>
+</section>
diff --git a/nixos/lib/build-vms.nix b/nixos/lib/build-vms.nix
index 1bad63b9194ce..b1575fc13bbdf 100644
--- a/nixos/lib/build-vms.nix
+++ b/nixos/lib/build-vms.nix
@@ -3,8 +3,10 @@
   minimal ? false
 , # Ignored
   config ? null
-  # Nixpkgs, for qemu, lib and more
-, pkgs
+, # Nixpkgs, for qemu, lib and more
+  pkgs
+, # !!! See comment about args in lib/modules.nix
+  specialArgs ? {}
 , # NixOS configuration to add to the VMs
   extraConfigurations ? []
 }:
@@ -31,7 +33,7 @@ rec {
     nodes: configurations:
 
     import ./eval-config.nix {
-      inherit system;
+      inherit system specialArgs;
       modules = configurations ++ extraConfigurations;
       baseModules =  (import ../modules/module-list.nix) ++
         [ ../modules/virtualisation/qemu-vm.nix
diff --git a/nixos/lib/eval-config.nix b/nixos/lib/eval-config.nix
index c8824c2690d33..15429a7160c5a 100644
--- a/nixos/lib/eval-config.nix
+++ b/nixos/lib/eval-config.nix
@@ -24,11 +24,11 @@
   check ? true
 , prefix ? []
 , lib ? import ../../lib
+, extraModules ? let e = builtins.getEnv "NIXOS_EXTRA_MODULE_PATH";
+                 in if e == "" then [] else [(import e)]
 }:
 
 let extraArgs_ = extraArgs; pkgs_ = pkgs;
-    extraModules = let e = builtins.getEnv "NIXOS_EXTRA_MODULE_PATH";
-                   in if e == "" then [] else [(import e)];
 in
 
 let
diff --git a/nixos/lib/make-disk-image.nix b/nixos/lib/make-disk-image.nix
index 9364aab327705..8aa606a56af80 100644
--- a/nixos/lib/make-disk-image.nix
+++ b/nixos/lib/make-disk-image.nix
@@ -5,21 +5,32 @@
   config
 
 , # The size of the disk, in megabytes.
-  diskSize
+  # if "auto" size is calculated based on the contents copied to it and
+  #   additionalSpace is taken into account.
+  diskSize ? "auto"
 
-  # The files and directories to be placed in the target file system.
+, # additional disk space to be added to the image if diskSize "auto"
+  # is used
+  additionalSpace ? "512M"
+
+, # size of the boot partition, is only used if partitionTableType is
+  # either "efi" or "hybrid"
+  bootSize ? "256M"
+
+, # The files and directories to be placed in the target file system.
   # This is a list of attribute sets {source, target} where `source'
   # is the file system object (regular file or directory) to be
   # grafted in the file system at path `target'.
-, contents ? []
+  contents ? []
 
 , # Type of partition table to use; either "legacy", "efi", or "none".
   # For "efi" images, the GPT partition table is used and a mandatory ESP
   #   partition of reasonable size is created in addition to the root partition.
-  #   If `installBootLoader` is true, GRUB will be installed in EFI mode.
   # For "legacy", the msdos partition table is used and a single large root
-  #   partition is created. If `installBootLoader` is true, GRUB will be
-  #   installed in legacy mode.
+  #   partition is created.
+  # For "hybrid", the GPT partition table is used and a mandatory ESP
+  #   partition of reasonable size is created in addition to the root partition.
+  #   Also a legacy MBR will be present.
   # For "none", no partition table is created. Enabling `installBootLoader`
   #   most likely fails as GRUB will probably refuse to install.
   partitionTableType ? "legacy"
@@ -43,7 +54,7 @@
   format ? "raw"
 }:
 
-assert partitionTableType == "legacy" || partitionTableType == "efi" || partitionTableType == "none";
+assert partitionTableType == "legacy" || partitionTableType == "efi" || partitionTableType == "hybrid" || partitionTableType == "none";
 # We use -E offset=X below, which is only supported by e2fsprogs
 assert partitionTableType != "none" -> fsType == "ext4";
 
@@ -60,11 +71,12 @@ let format' = format; in let
     vdi   = "vdi";
     vpc   = "vhd";
     raw   = "img";
-  }.${format};
+  }.${format} or format;
 
   rootPartition = { # switch-case
     legacy = "1";
     efi = "2";
+    hybrid = "3";
   }.${partitionTableType};
 
   partitionDiskScript = { # switch-case
@@ -76,9 +88,18 @@ let format' = format; in let
     efi = ''
       parted --script $diskImage -- \
         mklabel gpt \
-        mkpart ESP fat32 8MiB 256MiB \
+        mkpart ESP fat32 8MiB ${bootSize} \
         set 1 boot on \
-        mkpart primary ext4 256MiB -1
+        mkpart primary ext4 ${bootSize} -1
+    '';
+    hybrid = ''
+      parted --script $diskImage -- \
+        mklabel gpt \
+        mkpart ESP fat32 8MiB ${bootSize} \
+        set 1 boot on \
+        mkpart no-fs 0 1024KiB \
+        set 2 bios_grub on \
+        mkpart primary ext4 ${bootSize} -1
     '';
     none = "";
   }.${partitionTableType};
@@ -129,19 +150,6 @@ let format' = format; in let
     }
 
     mkdir $out
-    diskImage=nixos.raw
-    truncate -s ${toString diskSize}M $diskImage
-
-    ${partitionDiskScript}
-
-    ${if partitionTableType != "none" then ''
-      # Get start & length of the root partition in sectors to $START and $SECTORS.
-      eval $(partx $diskImage -o START,SECTORS --nr ${rootPartition} --pairs)
-
-      mkfs.${fsType} -F -L ${label} $diskImage -E offset=$(sectorsToBytes $START) $(sectorsToKilobytes $SECTORS)K
-    '' else ''
-      mkfs.${fsType} -F -L ${label} $diskImage
-    ''}
 
     root="$PWD/root"
     mkdir -p $root
@@ -181,10 +189,36 @@ let format' = format; in let
     export NIX_STATE_DIR=$TMPDIR/state
     nix-store --load-db < ${closureInfo}/registration
 
+    chmod 755 "$TMPDIR"
     echo "running nixos-install..."
     nixos-install --root $root --no-bootloader --no-root-passwd \
       --system ${config.system.build.toplevel} --channel ${channelSources} --substituters ""
 
+    diskImage=nixos.raw
+
+    ${if diskSize == "auto" then ''
+      ${if partitionTableType == "efi" || partitionTableType == "hybrid" then ''
+        additionalSpace=$(( ($(numfmt --from=iec '${additionalSpace}') + $(numfmt --from=iec '${bootSize}')) / 1000 ))
+      '' else ''
+        additionalSpace=$(( $(numfmt --from=iec '${additionalSpace}') / 1000 ))
+      ''}
+      diskSize=$(( $(set -- $(du -d0 $root); echo "$1") + $additionalSpace ))
+      truncate -s "$diskSize"K $diskImage
+    '' else ''
+      truncate -s ${toString diskSize}M $diskImage
+    ''}
+
+    ${partitionDiskScript}
+
+    ${if partitionTableType != "none" then ''
+      # Get start & length of the root partition in sectors to $START and $SECTORS.
+      eval $(partx $diskImage -o START,SECTORS --nr ${rootPartition} --pairs)
+
+      mkfs.${fsType} -F -L ${label} $diskImage -E offset=$(sectorsToBytes $START) $(sectorsToKilobytes $SECTORS)K
+    '' else ''
+      mkfs.${fsType} -F -L ${label} $diskImage
+    ''}
+
     echo "copying staging root to image..."
     cptofs -p ${optionalString (partitionTableType != "none") "-P ${rootPartition}"} -t ${fsType} -i $diskImage $root/* /
   '';
@@ -218,7 +252,7 @@ in pkgs.vmTools.runInLinuxVM (
 
       # Create the ESP and mount it. Unlike e2fsprogs, mkfs.vfat doesn't support an
       # '-E offset=X' option, so we can't do this outside the VM.
-      ${optionalString (partitionTableType == "efi") ''
+      ${optionalString (partitionTableType == "efi" || partitionTableType == "hybrid") ''
         mkdir -p /mnt/boot
         mkfs.vfat -n ESP /dev/vda1
         mount /dev/vda1 /mnt/boot
diff --git a/nixos/lib/make-ext4-fs.nix b/nixos/lib/make-ext4-fs.nix
index 627ac324cf57e..33dbc8f5ec461 100644
--- a/nixos/lib/make-ext4-fs.nix
+++ b/nixos/lib/make-ext4-fs.nix
@@ -17,7 +17,7 @@
 , e2fsprogs
 , libfaketime
 , perl
-, lkl
+, fakeroot
 }:
 
 let
@@ -26,7 +26,7 @@ in
 pkgs.stdenv.mkDerivation {
   name = "ext4-fs.img${lib.optionalString compressImage ".zst"}";
 
-  nativeBuildInputs = [ e2fsprogs.bin libfaketime perl lkl ]
+  nativeBuildInputs = [ e2fsprogs.bin libfaketime perl fakeroot ]
   ++ lib.optional compressImage zstd;
 
   buildCommand =
@@ -37,32 +37,34 @@ pkgs.stdenv.mkDerivation {
       ${populateImageCommands}
       )
 
-      # Add the closures of the top-level store objects.
-      storePaths=$(cat ${sdClosureInfo}/store-paths)
+      echo "Preparing store paths for image..."
+
+      # Create nix/store before copying path
+      mkdir -p ./rootImage/nix/store
+
+      xargs -I % cp -a --reflink=auto % -t ./rootImage/nix/store/ < ${sdClosureInfo}/store-paths
+      (
+        GLOBIGNORE=".:.."
+        shopt -u dotglob
+
+        for f in ./files/*; do
+            cp -a --reflink=auto -t ./rootImage/ "$f"
+        done
+      )
+
+      # Also include a manifest of the closures in a format suitable for nix-store --load-db
+      cp ${sdClosureInfo}/registration ./rootImage/nix-path-registration
 
       # Make a crude approximation of the size of the target image.
       # If the script starts failing, increase the fudge factors here.
-      numInodes=$(find $storePaths ./files | wc -l)
-      numDataBlocks=$(du -s -c -B 4096 --apparent-size $storePaths ./files | tail -1 | awk '{ print int($1 * 1.03) }')
+      numInodes=$(find ./rootImage | wc -l)
+      numDataBlocks=$(du -s -c -B 4096 --apparent-size ./rootImage | tail -1 | awk '{ print int($1 * 1.10) }')
       bytes=$((2 * 4096 * $numInodes + 4096 * $numDataBlocks))
       echo "Creating an EXT4 image of $bytes bytes (numInodes=$numInodes, numDataBlocks=$numDataBlocks)"
 
       truncate -s $bytes $img
-      faketime -f "1970-01-01 00:00:01" mkfs.ext4 -L ${volumeLabel} -U ${uuid} $img
-
-      # Also include a manifest of the closures in a format suitable for nix-store --load-db.
-      cp ${sdClosureInfo}/registration nix-path-registration
-      cptofs -t ext4 -i $img nix-path-registration /
-
-      # Create nix/store before copying paths
-      faketime -f "1970-01-01 00:00:01" mkdir -p nix/store
-      cptofs -t ext4 -i $img nix /
-
-      echo "copying store paths to image..."
-      cptofs -t ext4 -i $img $storePaths /nix/store/
 
-      echo "copying files to image..."
-      cptofs -t ext4 -i $img ./files/* /
+      faketime -f "1970-01-01 00:00:01" fakeroot mkfs.ext4 -L ${volumeLabel} -U ${uuid} -d ./rootImage $img
 
       export EXT2FS_NO_MTAB_OK=yes
       # I have ended up with corrupted images sometimes, I suspect that happens when the build machine's disk gets full during the build.
diff --git a/nixos/lib/make-iso9660-image.nix b/nixos/lib/make-iso9660-image.nix
index 12a6cf6499663..6a0e0e7c635a4 100644
--- a/nixos/lib/make-iso9660-image.nix
+++ b/nixos/lib/make-iso9660-image.nix
@@ -1,4 +1,4 @@
-{ stdenv, closureInfo, xorriso, syslinux
+{ stdenv, closureInfo, xorriso, syslinux, libossp_uuid
 
 , # The file name of the resulting ISO image.
   isoName ? "cd.iso"
@@ -48,7 +48,7 @@ assert usbBootable -> isohybridMbrImage != "";
 stdenv.mkDerivation {
   name = isoName;
   builder = ./make-iso9660-image.sh;
-  buildInputs = [ xorriso syslinux zstd ];
+  buildInputs = [ xorriso syslinux zstd libossp_uuid ];
 
   inherit isoName bootable bootImage compressImage volumeID efiBootImage efiBootable isohybridMbrImage usbBootable;
 
diff --git a/nixos/lib/make-iso9660-image.sh b/nixos/lib/make-iso9660-image.sh
index d64fe9a365e75..4740b05f95571 100644
--- a/nixos/lib/make-iso9660-image.sh
+++ b/nixos/lib/make-iso9660-image.sh
@@ -99,7 +99,12 @@ done
 
 mkdir -p $out/iso
 
+# daed2280-b91e-42c0-aed6-82c825ca41f3 is an arbitrary namespace, to prevent
+# independent applications from generating the same UUID for the same value.
+# (the chance of that being problematic seem pretty slim here, but that's how
+# version-5 UUID's work)
 xorriso="xorriso
+ -boot_image any gpt_disk_guid=$(uuid -v 5 daed2280-b91e-42c0-aed6-82c825ca41f3 $out | tr -d -)
  -as mkisofs
  -iso-level 3
  -volid ${volumeID}
@@ -118,15 +123,6 @@ xorriso="xorriso
 
 $xorriso -output $out/iso/$isoName
 
-if test -n "$usbBootable"; then
-    echo "Making image hybrid..."
-    if test -n "$efiBootable"; then
-        isohybrid --uefi $out/iso/$isoName
-    else
-        isohybrid $out/iso/$isoName
-    fi
-fi
-
 if test -n "$compressImage"; then
     echo "Compressing image..."
     zstd -T$NIX_BUILD_CORES --rm $out/iso/$isoName
diff --git a/nixos/lib/make-options-doc/default.nix b/nixos/lib/make-options-doc/default.nix
index 772b7d3add951..a1161621f0d49 100644
--- a/nixos/lib/make-options-doc/default.nix
+++ b/nixos/lib/make-options-doc/default.nix
@@ -36,7 +36,7 @@ let
     // lib.optionalAttrs (opt ? example) { example = substFunction opt.example; }
     // lib.optionalAttrs (opt ? default) { default = substFunction opt.default; }
     // lib.optionalAttrs (opt ? type) { type = substFunction opt.type; }
-    // lib.optionalAttrs (opt ? relatedPackages && opt.relatedPackages != []) { relatedPackages = genRelatedPackages opt.relatedPackages; }
+    // lib.optionalAttrs (opt ? relatedPackages && opt.relatedPackages != []) { relatedPackages = genRelatedPackages opt.relatedPackages opt.name; }
    );
 
   # Generate DocBook documentation for a list of packages. This is
@@ -48,7 +48,7 @@ let
   # - a list:    that will be interpreted as an attribute path from `pkgs`,
   # - an attrset: that can specify `name`, `path`, `package`, `comment`
   #   (either of `name`, `path` is required, the rest are optional).
-  genRelatedPackages = packages:
+  genRelatedPackages = packages: optName:
     let
       unpack = p: if lib.isString p then { name = p; }
                   else if lib.isList p then { path = p; }
@@ -58,7 +58,7 @@ let
           title = args.title or null;
           name = args.name or (lib.concatStringsSep "." args.path);
           path = args.path or [ args.name ];
-          package = args.package or (lib.attrByPath path (throw "Invalid package attribute path `${toString path}'") pkgs);
+          package = args.package or (lib.attrByPath path (throw "Invalid package attribute path `${toString path}' found while evaluating `relatedPackages' of option `${optName}'") pkgs);
         in "<listitem>"
         + "<para><literal>${lib.optionalString (title != null) "${title} aka "}pkgs.${name} (${package.meta.name})</literal>"
         + lib.optionalString (!package.meta.available) " <emphasis>[UNAVAILABLE]</emphasis>"
diff --git a/nixos/lib/make-options-doc/options-to-docbook.xsl b/nixos/lib/make-options-doc/options-to-docbook.xsl
index 72ac89d4ff62c..18d19fddaca24 100644
--- a/nixos/lib/make-options-doc/options-to-docbook.xsl
+++ b/nixos/lib/make-options-doc/options-to-docbook.xsl
@@ -20,7 +20,7 @@
       <title>Configuration Options</title>
       <variablelist xml:id="configuration-variable-list">
         <xsl:for-each select="attrs">
-          <xsl:variable name="id" select="concat('opt-', str:replace(str:replace(str:replace(str:replace(attr[@name = 'name']/string/@value, '*', '_'), '&lt;', '_'), '>', '_'), '?', '_'))" />
+          <xsl:variable name="id" select="concat('opt-', str:replace(str:replace(str:replace(attr[@name = 'name']/string/@value, '*', '_'), '&lt;', '_'), '>', '_'))" />
           <varlistentry>
             <term xlink:href="#{$id}">
               <xsl:attribute name="xml:id"><xsl:value-of select="$id"/></xsl:attribute>
diff --git a/nixos/lib/qemu-flags.nix b/nixos/lib/qemu-flags.nix
index 859d9e975fec7..0f06624589354 100644
--- a/nixos/lib/qemu-flags.nix
+++ b/nixos/lib/qemu-flags.nix
@@ -2,13 +2,18 @@
 { pkgs }:
 
 let
-  zeroPad = n: if n < 10 then "0${toString n}" else toString n;
+  zeroPad = n:
+    pkgs.lib.optionalString (n < 16) "0" +
+      (if n > 255
+       then throw "Can't have more than 255 nets or nodes!"
+       else pkgs.lib.toHexString n);
 in
 
-{
+rec {
+  qemuNicMac = net: machine: "52:54:00:12:${zeroPad net}:${zeroPad machine}";
 
   qemuNICFlags = nic: net: machine:
-    [ "-device virtio-net-pci,netdev=vlan${toString nic},mac=52:54:00:12:${zeroPad net}:${zeroPad machine}"
+    [ "-device virtio-net-pci,netdev=vlan${toString nic},mac=${qemuNicMac net machine}"
       "-netdev vde,id=vlan${toString nic},sock=$QEMU_VDE_SOCKET_${toString net}"
     ];
 
@@ -17,9 +22,9 @@ in
         else throw "Unknown QEMU serial device for system '${pkgs.stdenv.hostPlatform.system}'";
 
   qemuBinary = qemuPkg: {
-    x86_64-linux = "${qemuPkg}/bin/qemu-kvm -cpu host";
+    x86_64-linux = "${qemuPkg}/bin/qemu-kvm -cpu max";
     armv7l-linux = "${qemuPkg}/bin/qemu-system-arm -enable-kvm -machine virt -cpu host";
     aarch64-linux = "${qemuPkg}/bin/qemu-system-aarch64 -enable-kvm -machine virt,gic-version=host -cpu host";
-    x86_64-darwin = "${qemuPkg}/bin/qemu-kvm -cpu host";
+    x86_64-darwin = "${qemuPkg}/bin/qemu-kvm -cpu max";
   }.${pkgs.stdenv.hostPlatform.system} or "${qemuPkg}/bin/qemu-kvm";
 }
diff --git a/nixos/lib/test-driver/Logger.pm b/nixos/lib/test-driver/Logger.pm
deleted file mode 100644
index 080310ea34e08..0000000000000
--- a/nixos/lib/test-driver/Logger.pm
+++ /dev/null
@@ -1,75 +0,0 @@
-package Logger;
-
-use strict;
-use Thread::Queue;
-use XML::Writer;
-use Encode qw(decode encode);
-use Time::HiRes qw(clock_gettime CLOCK_MONOTONIC);
-
-sub new {
-    my ($class) = @_;
-    
-    my $logFile = defined $ENV{LOGFILE} ? "$ENV{LOGFILE}" : "/dev/null";
-    my $log = new XML::Writer(OUTPUT => new IO::File(">$logFile"));
-    
-    my $self = {
-        log => $log,
-        logQueue => Thread::Queue->new()
-    };
-    
-    $self->{log}->startTag("logfile");
-    
-    bless $self, $class;
-    return $self;
-}
-
-sub close {
-    my ($self) = @_;
-    $self->{log}->endTag("logfile");
-    $self->{log}->end;
-}
-
-sub drainLogQueue {
-    my ($self) = @_;
-    while (defined (my $item = $self->{logQueue}->dequeue_nb())) {
-        $self->{log}->dataElement("line", sanitise($item->{msg}), 'machine' => $item->{machine}, 'type' => 'serial');
-    }
-}
-
-sub maybePrefix {
-    my ($msg, $attrs) = @_;
-    $msg = $attrs->{machine} . ": " . $msg if defined $attrs->{machine};
-    return $msg;
-}
-
-sub nest {
-    my ($self, $msg, $coderef, $attrs) = @_;
-    print STDERR maybePrefix("$msg\n", $attrs);
-    $self->{log}->startTag("nest");
-    $self->{log}->dataElement("head", $msg, %{$attrs});
-    my $now = clock_gettime(CLOCK_MONOTONIC);
-    $self->drainLogQueue();
-    eval { &$coderef };
-    my $res = $@;
-    $self->drainLogQueue();
-    $self->log(sprintf("(%.2f seconds)", clock_gettime(CLOCK_MONOTONIC) - $now));
-    $self->{log}->endTag("nest");
-    die $@ if $@;
-}
-
-sub sanitise {
-    my ($s) = @_;
-    $s =~ s/[[:cntrl:]\xff]//g;
-    $s = decode('UTF-8', $s, Encode::FB_DEFAULT);
-    return encode('UTF-8', $s, Encode::FB_CROAK);
-}
-
-sub log {
-    my ($self, $msg, $attrs) = @_;
-    chomp $msg;
-    print STDERR maybePrefix("$msg\n", $attrs);
-    $self->drainLogQueue();
-    $self->{log}->dataElement("line", $msg, %{$attrs});
-}
-
-1;
diff --git a/nixos/lib/test-driver/Machine.pm b/nixos/lib/test-driver/Machine.pm
deleted file mode 100644
index 4d3d63cd2dbf9..0000000000000
--- a/nixos/lib/test-driver/Machine.pm
+++ /dev/null
@@ -1,734 +0,0 @@
-package Machine;
-
-use strict;
-use threads;
-use Socket;
-use IO::Handle;
-use POSIX qw(dup2);
-use FileHandle;
-use Cwd;
-use File::Basename;
-use File::Path qw(make_path);
-use File::Slurp;
-use Time::HiRes qw(clock_gettime CLOCK_MONOTONIC);
-
-
-my $showGraphics = defined $ENV{'DISPLAY'};
-
-my $sharedDir;
-
-
-sub new {
-    my ($class, $args) = @_;
-
-    my $startCommand = $args->{startCommand};
-
-    my $name = $args->{name};
-    if (!$name) {
-        $startCommand =~ /run-(.*)-vm$/ if defined $startCommand;
-        $name = $1 || "machine";
-    }
-
-    if (!$startCommand) {
-        # !!! merge with qemu-vm.nix.
-        my $netBackend = "-netdev user,id=net0";
-        my $netFrontend = "-device virtio-net-pci,netdev=net0";
-
-        $netBackend .= "," . $args->{netBackendArgs}
-            if defined $args->{netBackendArgs};
-
-        $netFrontend .= "," . $args->{netFrontendArgs}
-            if defined $args->{netFrontendArgs};
-
-        $startCommand =
-            "qemu-kvm -m 384 $netBackend $netFrontend \$QEMU_OPTS ";
-
-        if (defined $args->{hda}) {
-            if ($args->{hdaInterface} eq "scsi") {
-                $startCommand .= "-drive id=hda,file="
-                               . Cwd::abs_path($args->{hda})
-                               . ",werror=report,if=none "
-                               . "-device scsi-hd,drive=hda ";
-            } else {
-                $startCommand .= "-drive file=" . Cwd::abs_path($args->{hda})
-                               . ",if=" . $args->{hdaInterface}
-                               . ",werror=report ";
-            }
-        }
-
-        $startCommand .= "-cdrom $args->{cdrom} "
-            if defined $args->{cdrom};
-        $startCommand .= "-device piix3-usb-uhci -drive id=usbdisk,file=$args->{usb},if=none,readonly -device usb-storage,drive=usbdisk "
-            if defined $args->{usb};
-        $startCommand .= "-bios $args->{bios} "
-            if defined $args->{bios};
-        $startCommand .= $args->{qemuFlags} || "";
-    }
-
-    my $tmpDir = $ENV{'TMPDIR'} || "/tmp";
-    unless (defined $sharedDir) {
-        $sharedDir = $tmpDir . "/xchg-shared";
-        make_path($sharedDir, { mode => 0700, owner => $< });
-    }
-
-    my $allowReboot = 0;
-    $allowReboot = $args->{allowReboot} if defined $args->{allowReboot};
-
-    my $self = {
-        startCommand => $startCommand,
-        name => $name,
-        allowReboot => $allowReboot,
-        booted => 0,
-        pid => 0,
-        connected => 0,
-        socket => undef,
-        stateDir => "$tmpDir/vm-state-$name",
-        monitor => undef,
-        log => $args->{log},
-        redirectSerial => $args->{redirectSerial} // 1,
-    };
-
-    mkdir $self->{stateDir}, 0700;
-
-    bless $self, $class;
-    return $self;
-}
-
-
-sub log {
-    my ($self, $msg) = @_;
-    $self->{log}->log($msg, { machine => $self->{name} });
-}
-
-
-sub nest {
-    my ($self, $msg, $coderef, $attrs) = @_;
-    $self->{log}->nest($msg, $coderef, { %{$attrs || {}}, machine => $self->{name} });
-}
-
-
-sub name {
-    my ($self) = @_;
-    return $self->{name};
-}
-
-
-sub stateDir {
-    my ($self) = @_;
-    return $self->{stateDir};
-}
-
-
-sub start {
-    my ($self) = @_;
-    return if $self->{booted};
-
-    $self->log("starting vm");
-
-    # Create a socket pair for the serial line input/output of the VM.
-    my ($serialP, $serialC);
-    socketpair($serialP, $serialC, PF_UNIX, SOCK_STREAM, 0) or die;
-
-    # Create a Unix domain socket to which QEMU's monitor will connect.
-    my $monitorPath = $self->{stateDir} . "/monitor";
-    unlink $monitorPath;
-    my $monitorS;
-    socket($monitorS, PF_UNIX, SOCK_STREAM, 0) or die;
-    bind($monitorS, sockaddr_un($monitorPath)) or die "cannot bind monitor socket: $!";
-    listen($monitorS, 1) or die;
-
-    # Create a Unix domain socket to which the root shell in the guest will connect.
-    my $shellPath = $self->{stateDir} . "/shell";
-    unlink $shellPath;
-    my $shellS;
-    socket($shellS, PF_UNIX, SOCK_STREAM, 0) or die;
-    bind($shellS, sockaddr_un($shellPath)) or die "cannot bind shell socket: $!";
-    listen($shellS, 1) or die;
-
-    # Start the VM.
-    my $pid = fork();
-    die if $pid == -1;
-
-    if ($pid == 0) {
-        close $serialP;
-        close $monitorS;
-        close $shellS;
-        if ($self->{redirectSerial}) {
-            open NUL, "</dev/null" or die;
-            dup2(fileno(NUL), fileno(STDIN));
-            dup2(fileno($serialC), fileno(STDOUT));
-            dup2(fileno($serialC), fileno(STDERR));
-        }
-        $ENV{TMPDIR} = $self->{stateDir};
-        $ENV{SHARED_DIR} = $sharedDir;
-        $ENV{USE_TMPDIR} = 1;
-        $ENV{QEMU_OPTS} =
-            ($self->{allowReboot} ? "" : "-no-reboot ") .
-            "-monitor unix:./monitor -chardev socket,id=shell,path=./shell " .
-            "-device virtio-serial -device virtconsole,chardev=shell " .
-            "-device virtio-rng-pci " .
-            ($showGraphics ? "-serial stdio" : "-nographic") . " " . ($ENV{QEMU_OPTS} || "");
-        chdir $self->{stateDir} or die;
-        exec $self->{startCommand};
-        die "running VM script: $!";
-    }
-
-    # Process serial line output.
-    close $serialC;
-
-    threads->create(\&processSerialOutput, $self, $serialP)->detach;
-
-    sub processSerialOutput {
-        my ($self, $serialP) = @_;
-        while (<$serialP>) {
-            chomp;
-            s/\r$//;
-            print STDERR $self->{name}, "# $_\n";
-            $self->{log}->{logQueue}->enqueue({msg => $_, machine => $self->{name}}); # !!!
-        }
-    }
-
-    eval {
-        local $SIG{CHLD} = sub { die "QEMU died prematurely\n"; };
-
-        # Wait until QEMU connects to the monitor.
-        accept($self->{monitor}, $monitorS) or die;
-
-        # Wait until QEMU connects to the root shell socket.  QEMU
-        # does so immediately; this doesn't mean that the root shell
-        # has connected yet inside the guest.
-        accept($self->{socket}, $shellS) or die;
-        $self->{socket}->autoflush(1);
-    };
-    die "$@" if $@;
-
-    $self->waitForMonitorPrompt;
-
-    $self->log("QEMU running (pid $pid)");
-
-    $self->{pid} = $pid;
-    $self->{booted} = 1;
-}
-
-
-# Send a command to the monitor and wait for it to finish.  TODO: QEMU
-# also has a JSON-based monitor interface now, but it doesn't support
-# all commands yet.  We should use it once it does.
-sub sendMonitorCommand {
-    my ($self, $command) = @_;
-    $self->log("sending monitor command: $command");
-    syswrite $self->{monitor}, "$command\n";
-    return $self->waitForMonitorPrompt;
-}
-
-
-# Wait until the monitor sends "(qemu) ".
-sub waitForMonitorPrompt {
-    my ($self) = @_;
-    my $res = "";
-    my $s;
-    while (sysread($self->{monitor}, $s, 1024)) {
-        $res .= $s;
-        last if $res =~ s/\(qemu\) $//;
-    }
-    return $res;
-}
-
-
-# Call the given code reference repeatedly, with 1 second intervals,
-# until it returns 1 or a timeout is reached.
-sub retry {
-    my ($coderef) = @_;
-    my $n;
-    for ($n = 899; $n >=0; $n--) {
-        return if &$coderef($n);
-        sleep 1;
-    }
-    die "action timed out after $n seconds";
-}
-
-
-sub connect {
-    my ($self) = @_;
-    return if $self->{connected};
-
-    $self->nest("waiting for the VM to finish booting", sub {
-
-        $self->start;
-
-        my $now = clock_gettime(CLOCK_MONOTONIC);
-        local $SIG{ALRM} = sub { die "timed out waiting for the VM to connect\n"; };
-        alarm 600;
-        readline $self->{socket} or die "the VM quit before connecting\n";
-        alarm 0;
-
-        $self->log("connected to guest root shell");
-        # We're interested in tracking how close we are to `alarm`.
-        $self->log(sprintf("(connecting took %.2f seconds)", clock_gettime(CLOCK_MONOTONIC) - $now));
-        $self->{connected} = 1;
-
-    });
-}
-
-
-sub waitForShutdown {
-    my ($self) = @_;
-    return unless $self->{booted};
-
-    $self->nest("waiting for the VM to power off", sub {
-        waitpid $self->{pid}, 0;
-        $self->{pid} = 0;
-        $self->{booted} = 0;
-        $self->{connected} = 0;
-    });
-}
-
-
-sub isUp {
-    my ($self) = @_;
-    return $self->{booted} && $self->{connected};
-}
-
-
-sub execute_ {
-    my ($self, $command) = @_;
-
-    $self->connect;
-
-    print { $self->{socket} } ("( $command ); echo '|!=EOF' \$?\n");
-
-    my $out = "";
-
-    while (1) {
-        my $line = readline($self->{socket});
-        die "connection to VM lost unexpectedly" unless defined $line;
-        #$self->log("got line: $line");
-        if ($line =~ /^(.*)\|\!\=EOF\s+(\d+)$/) {
-            $out .= $1;
-            $self->log("exit status $2");
-            return ($2, $out);
-        }
-        $out .= $line;
-    }
-}
-
-
-sub execute {
-    my ($self, $command) = @_;
-    my @res;
-    $self->nest("running command: $command", sub {
-        @res = $self->execute_($command);
-    });
-    return @res;
-}
-
-
-sub succeed {
-    my ($self, @commands) = @_;
-
-    my $res;
-    foreach my $command (@commands) {
-        $self->nest("must succeed: $command", sub {
-            my ($status, $out) = $self->execute_($command);
-            if ($status != 0) {
-                $self->log("output: $out");
-                die "command `$command' did not succeed (exit code $status)\n";
-            }
-            $res .= $out;
-        });
-    }
-
-    return $res;
-}
-
-
-sub mustSucceed {
-    succeed @_;
-}
-
-
-sub waitUntilSucceeds {
-    my ($self, $command) = @_;
-    $self->nest("waiting for success: $command", sub {
-        retry sub {
-            my ($status, $out) = $self->execute($command);
-            return 1 if $status == 0;
-        };
-    });
-}
-
-
-sub waitUntilFails {
-    my ($self, $command) = @_;
-    $self->nest("waiting for failure: $command", sub {
-        retry sub {
-            my ($status, $out) = $self->execute($command);
-            return 1 if $status != 0;
-        };
-    });
-}
-
-
-sub fail {
-    my ($self, $command) = @_;
-    $self->nest("must fail: $command", sub {
-        my ($status, $out) = $self->execute_($command);
-        die "command `$command' unexpectedly succeeded"
-            if $status == 0;
-    });
-}
-
-
-sub mustFail {
-    fail @_;
-}
-
-
-sub getUnitInfo {
-    my ($self, $unit, $user) = @_;
-    my ($status, $lines) = $self->systemctl("--no-pager show \"$unit\"", $user);
-    return undef if $status != 0;
-    my $info = {};
-    foreach my $line (split '\n', $lines) {
-        $line =~ /^([^=]+)=(.*)$/ or next;
-        $info->{$1} = $2;
-    }
-    return $info;
-}
-
-sub systemctl {
-    my ($self, $q, $user) = @_;
-    if ($user) {
-        $q =~ s/'/\\'/g;
-        return $self->execute("su -l $user -c \$'XDG_RUNTIME_DIR=/run/user/`id -u` systemctl --user $q'");
-    }
-
-    return $self->execute("systemctl $q");
-}
-
-# Fail if the given systemd unit is not in the "active" state.
-sub requireActiveUnit {
-    my ($self, $unit) = @_;
-    $self->nest("checking if unit ‘$unit’ has reached state 'active'", sub {
-        my $info = $self->getUnitInfo($unit);
-        my $state = $info->{ActiveState};
-        if ($state ne "active") {
-            die "Expected unit ‘$unit’ to to be in state 'active' but it is in state ‘$state’\n";
-        };
-    });
-}
-
-# Wait for a systemd unit to reach the "active" state.
-sub waitForUnit {
-    my ($self, $unit, $user) = @_;
-    $self->nest("waiting for unit ‘$unit’", sub {
-        retry sub {
-            my $info = $self->getUnitInfo($unit, $user);
-            my $state = $info->{ActiveState};
-            die "unit ‘$unit’ reached state ‘$state’\n" if $state eq "failed";
-            if ($state eq "inactive") {
-                # If there are no pending jobs, then assume this unit
-                # will never reach active state.
-                my ($status, $jobs) = $self->systemctl("list-jobs --full 2>&1", $user);
-                if ($jobs =~ /No jobs/) {  # FIXME: fragile
-                    # Handle the case where the unit may have started
-                    # between the previous getUnitInfo() and
-                    # list-jobs.
-                    my $info2 = $self->getUnitInfo($unit);
-                    die "unit ‘$unit’ is inactive and there are no pending jobs\n"
-                        if $info2->{ActiveState} eq $state;
-                }
-            }
-            return 1 if $state eq "active";
-        };
-    });
-}
-
-
-sub waitForJob {
-    my ($self, $jobName) = @_;
-    return $self->waitForUnit($jobName);
-}
-
-
-# Wait until the specified file exists.
-sub waitForFile {
-    my ($self, $fileName) = @_;
-    $self->nest("waiting for file ‘$fileName’", sub {
-        retry sub {
-            my ($status, $out) = $self->execute("test -e $fileName");
-            return 1 if $status == 0;
-        }
-    });
-}
-
-sub startJob {
-    my ($self, $jobName, $user) = @_;
-    $self->systemctl("start $jobName", $user);
-    # FIXME: check result
-}
-
-sub stopJob {
-    my ($self, $jobName, $user) = @_;
-    $self->systemctl("stop $jobName", $user);
-}
-
-
-# Wait until the machine is listening on the given TCP port.
-sub waitForOpenPort {
-    my ($self, $port) = @_;
-    $self->nest("waiting for TCP port $port", sub {
-        retry sub {
-            my ($status, $out) = $self->execute("nc -z localhost $port");
-            return 1 if $status == 0;
-        }
-    });
-}
-
-
-# Wait until the machine is not listening on the given TCP port.
-sub waitForClosedPort {
-    my ($self, $port) = @_;
-    retry sub {
-        my ($status, $out) = $self->execute("nc -z localhost $port");
-        return 1 if $status != 0;
-    }
-}
-
-
-sub shutdown {
-    my ($self) = @_;
-    return unless $self->{booted};
-
-    print { $self->{socket} } ("poweroff\n");
-
-    $self->waitForShutdown;
-}
-
-
-sub crash {
-    my ($self) = @_;
-    return unless $self->{booted};
-
-    $self->log("forced crash");
-
-    $self->sendMonitorCommand("quit");
-
-    $self->waitForShutdown;
-}
-
-
-# Make the machine unreachable by shutting down eth1 (the multicast
-# interface used to talk to the other VMs).  We keep eth0 up so that
-# the test driver can continue to talk to the machine.
-sub block {
-    my ($self) = @_;
-    $self->sendMonitorCommand("set_link virtio-net-pci.1 off");
-}
-
-
-# Make the machine reachable.
-sub unblock {
-    my ($self) = @_;
-    $self->sendMonitorCommand("set_link virtio-net-pci.1 on");
-}
-
-
-# Take a screenshot of the X server on :0.0.
-sub screenshot {
-    my ($self, $filename) = @_;
-    my $dir = $ENV{'out'} || Cwd::abs_path(".");
-    $filename = "$dir/${filename}.png" if $filename =~ /^\w+$/;
-    my $tmp = "${filename}.ppm";
-    my $name = basename($filename);
-    $self->nest("making screenshot ‘$name’", sub {
-        $self->sendMonitorCommand("screendump $tmp");
-        system("pnmtopng $tmp > ${filename}") == 0
-            or die "cannot convert screenshot";
-        unlink $tmp;
-    }, { image => $name } );
-}
-
-# Get the text of TTY<n>
-sub getTTYText {
-    my ($self, $tty) = @_;
-
-    my ($status, $out) = $self->execute("fold -w\$(stty -F /dev/tty${tty} size | awk '{print \$2}') /dev/vcs${tty}");
-    return $out;
-}
-
-# Wait until TTY<n>'s text matches a particular regular expression
-sub waitUntilTTYMatches {
-    my ($self, $tty, $regexp) = @_;
-
-    $self->nest("waiting for $regexp to appear on tty $tty", sub {
-        retry sub {
-            my ($retries_remaining) = @_;
-            if ($retries_remaining == 0) {
-                $self->log("Last chance to match /$regexp/ on TTY$tty, which currently contains:");
-                $self->log($self->getTTYText($tty));
-            }
-
-            return 1 if $self->getTTYText($tty) =~ /$regexp/;
-        }
-    });
-}
-
-# Debugging: Dump the contents of the TTY<n>
-sub dumpTTYContents {
-    my ($self, $tty) = @_;
-
-    $self->execute("fold -w 80 /dev/vcs${tty} | systemd-cat");
-}
-
-# Take a screenshot and return the result as text using optical character
-# recognition.
-sub getScreenText {
-    my ($self) = @_;
-
-    system("command -v tesseract &> /dev/null") == 0
-        or die "getScreenText used but enableOCR is false";
-
-    my $text;
-    $self->nest("performing optical character recognition", sub {
-        my $tmpbase = Cwd::abs_path(".")."/ocr";
-        my $tmpin = $tmpbase."in.ppm";
-
-        $self->sendMonitorCommand("screendump $tmpin");
-
-        my $magickArgs = "-filter Catrom -density 72 -resample 300 "
-                       . "-contrast -normalize -despeckle -type grayscale "
-                       . "-sharpen 1 -posterize 3 -negate -gamma 100 "
-                       . "-blur 1x65535";
-        my $tessArgs = "-c debug_file=/dev/null --psm 11 --oem 2";
-
-        $text = `convert $magickArgs $tmpin tiff:- | tesseract - - $tessArgs`;
-        my $status = $? >> 8;
-        unlink $tmpin;
-
-        die "OCR failed with exit code $status" if $status != 0;
-    });
-    return $text;
-}
-
-
-# Wait until a specific regexp matches the textual contents of the screen.
-sub waitForText {
-    my ($self, $regexp) = @_;
-    $self->nest("waiting for $regexp to appear on the screen", sub {
-        retry sub {
-            my ($retries_remaining) = @_;
-            if ($retries_remaining == 0) {
-                $self->log("Last chance to match /$regexp/ on the screen, which currently contains:");
-                $self->log($self->getScreenText);
-            }
-
-            return 1 if $self->getScreenText =~ /$regexp/;
-        }
-    });
-}
-
-
-# Wait until it is possible to connect to the X server.  Note that
-# testing the existence of /tmp/.X11-unix/X0 is insufficient.
-sub waitForX {
-    my ($self, $regexp) = @_;
-    $self->nest("waiting for the X11 server", sub {
-        retry sub {
-            my ($status, $out) = $self->execute("journalctl -b SYSLOG_IDENTIFIER=systemd | grep 'Reached target Current graphical'");
-            return 0 if $status != 0;
-            ($status, $out) = $self->execute("[ -e /tmp/.X11-unix/X0 ]");
-            return 1 if $status == 0;
-        }
-    });
-}
-
-
-sub getWindowNames {
-    my ($self) = @_;
-    my $res = $self->mustSucceed(
-        q{xwininfo -root -tree | sed 's/.*0x[0-9a-f]* \"\([^\"]*\)\".*/\1/; t; d'});
-    return split /\n/, $res;
-}
-
-
-sub waitForWindow {
-    my ($self, $regexp) = @_;
-    $self->nest("waiting for a window to appear", sub {
-        retry sub {
-            my @names = $self->getWindowNames;
-
-            my ($retries_remaining) = @_;
-            if ($retries_remaining == 0) {
-                $self->log("Last chance to match /$regexp/ on the the window list, which currently contains:");
-                $self->log(join(", ", @names));
-            }
-
-            foreach my $n (@names) {
-                return 1 if $n =~ /$regexp/;
-            }
-        }
-    });
-}
-
-
-sub copyFileFromHost {
-    my ($self, $from, $to) = @_;
-    my $s = `cat $from` or die;
-    $s =~ s/'/'\\''/g;
-    $self->mustSucceed("echo '$s' > $to");
-}
-
-
-my %charToKey = (
-    'A' => "shift-a", 'N' => "shift-n",  '-' => "0x0C", '_' => "shift-0x0C", '!' => "shift-0x02",
-    'B' => "shift-b", 'O' => "shift-o",  '=' => "0x0D", '+' => "shift-0x0D", '@' => "shift-0x03",
-    'C' => "shift-c", 'P' => "shift-p",  '[' => "0x1A", '{' => "shift-0x1A", '#' => "shift-0x04",
-    'D' => "shift-d", 'Q' => "shift-q",  ']' => "0x1B", '}' => "shift-0x1B", '$' => "shift-0x05",
-    'E' => "shift-e", 'R' => "shift-r",  ';' => "0x27", ':' => "shift-0x27", '%' => "shift-0x06",
-    'F' => "shift-f", 'S' => "shift-s", '\'' => "0x28", '"' => "shift-0x28", '^' => "shift-0x07",
-    'G' => "shift-g", 'T' => "shift-t",  '`' => "0x29", '~' => "shift-0x29", '&' => "shift-0x08",
-    'H' => "shift-h", 'U' => "shift-u", '\\' => "0x2B", '|' => "shift-0x2B", '*' => "shift-0x09",
-    'I' => "shift-i", 'V' => "shift-v",  ',' => "0x33", '<' => "shift-0x33", '(' => "shift-0x0A",
-    'J' => "shift-j", 'W' => "shift-w",  '.' => "0x34", '>' => "shift-0x34", ')' => "shift-0x0B",
-    'K' => "shift-k", 'X' => "shift-x",  '/' => "0x35", '?' => "shift-0x35",
-    'L' => "shift-l", 'Y' => "shift-y",  ' ' => "spc",
-    'M' => "shift-m", 'Z' => "shift-z", "\n" => "ret",
-);
-
-
-sub sendKeys {
-    my ($self, @keys) = @_;
-    foreach my $key (@keys) {
-        $key = $charToKey{$key} if exists $charToKey{$key};
-        $self->sendMonitorCommand("sendkey $key");
-    }
-}
-
-
-sub sendChars {
-    my ($self, $chars) = @_;
-    $self->nest("sending keys ‘$chars’", sub {
-        $self->sendKeys(split //, $chars);
-    });
-}
-
-
-# Sleep N seconds (in virtual guest time, not real time).
-sub sleep {
-    my ($self, $time) = @_;
-    $self->succeed("sleep $time");
-}
-
-
-# Forward a TCP port on the host to a TCP port on the guest.  Useful
-# during interactive testing.
-sub forwardPort {
-    my ($self, $hostPort, $guestPort) = @_;
-    $hostPort = 8080 unless defined $hostPort;
-    $guestPort = 80 unless defined $guestPort;
-    $self->sendMonitorCommand("hostfwd_add tcp::$hostPort-:$guestPort");
-}
-
-
-1;
diff --git a/nixos/lib/test-driver/test-driver.pl b/nixos/lib/test-driver/test-driver.pl
deleted file mode 100644
index a3354fb0e1eb8..0000000000000
--- a/nixos/lib/test-driver/test-driver.pl
+++ /dev/null
@@ -1,191 +0,0 @@
-#! /somewhere/perl -w
-
-use strict;
-use Machine;
-use Term::ReadLine;
-use IO::File;
-use IO::Pty;
-use Logger;
-use Cwd;
-use POSIX qw(_exit dup2);
-use Time::HiRes qw(clock_gettime CLOCK_MONOTONIC);
-
-$SIG{PIPE} = 'IGNORE'; # because Unix domain sockets may die unexpectedly
-
-STDERR->autoflush(1);
-
-my $log = new Logger;
-
-
-# Start vde_switch for each network required by the test.
-my %vlans;
-foreach my $vlan (split / /, $ENV{VLANS} || "") {
-    next if defined $vlans{$vlan};
-    # Start vde_switch as a child process.  We don't run it in daemon
-    # mode because we want the child process to be cleaned up when we
-    # die.  Since we have to make sure that the control socket is
-    # ready, we send a dummy command to vde_switch (via stdin) and
-    # wait for a reply.  Note that vde_switch requires stdin to be a
-    # TTY, so we create one.
-    $log->log("starting VDE switch for network $vlan");
-    my $socket = Cwd::abs_path "./vde$vlan.ctl";
-    my $pty = new IO::Pty;
-    my ($stdoutR, $stdoutW); pipe $stdoutR, $stdoutW;
-    my $pid = fork(); die "cannot fork" unless defined $pid;
-    if ($pid == 0) {
-        dup2(fileno($pty->slave), 0);
-        dup2(fileno($stdoutW), 1);
-        exec "vde_switch -s $socket --dirmode 0700" or _exit(1);
-    }
-    close $stdoutW;
-    print $pty "version\n";
-    readline $stdoutR or die "cannot start vde_switch";
-    $ENV{"QEMU_VDE_SOCKET_$vlan"} = $socket;
-    $vlans{$vlan} = $pty;
-    die unless -e "$socket/ctl";
-}
-
-
-my %vms;
-my $context = "";
-
-sub createMachine {
-    my ($args) = @_;
-    my $vm = Machine->new({%{$args}, log => $log, redirectSerial => ($ENV{USE_SERIAL} // "0") ne "1"});
-    $vms{$vm->name} = $vm;
-    $context .= "my \$" . $vm->name . " = \$vms{'" . $vm->name . "'}; ";
-    return $vm;
-}
-
-foreach my $vmScript (@ARGV) {
-    my $vm = createMachine({startCommand => $vmScript});
-}
-
-
-sub startAll {
-    $log->nest("starting all VMs", sub {
-        $_->start foreach values %vms;
-    });
-}
-
-
-# Wait until all VMs have terminated.
-sub joinAll {
-    $log->nest("waiting for all VMs to finish", sub {
-        $_->waitForShutdown foreach values %vms;
-    });
-}
-
-
-# In interactive tests, this allows the non-interactive test script to
-# be executed conveniently.
-sub testScript {
-    eval "$context $ENV{testScript};\n";
-    warn $@ if $@;
-}
-
-
-my $nrTests = 0;
-my $nrSucceeded = 0;
-
-
-sub subtest {
-    my ($name, $coderef) = @_;
-    $log->nest("subtest: $name", sub {
-        $nrTests++;
-        eval { &$coderef };
-        if ($@) {
-            $log->log("error: $@", { error => 1 });
-        } else {
-            $nrSucceeded++;
-        }
-    });
-}
-
-
-sub runTests {
-    if (defined $ENV{tests}) {
-        $log->nest("running the VM test script", sub {
-            eval "$context $ENV{tests}";
-            if ($@) {
-                $log->log("error: $@", { error => 1 });
-                die $@;
-            }
-        }, { expanded => 1 });
-    } else {
-        my $term = Term::ReadLine->new('nixos-vm-test');
-        $term->ReadHistory;
-        while (defined ($_ = $term->readline("> "))) {
-            eval "$context $_\n";
-            warn $@ if $@;
-        }
-        $term->WriteHistory;
-    }
-
-    # Copy the kernel coverage data for each machine, if the kernel
-    # has been compiled with coverage instrumentation.
-    $log->nest("collecting coverage data", sub {
-        foreach my $vm (values %vms) {
-            my $gcovDir = "/sys/kernel/debug/gcov";
-
-            next unless $vm->isUp();
-
-            my ($status, $out) = $vm->execute("test -e $gcovDir");
-            next if $status != 0;
-
-            # Figure out where to put the *.gcda files so that the
-            # report generator can find the corresponding kernel
-            # sources.
-            my $kernelDir = $vm->mustSucceed("echo \$(dirname \$(readlink -f /run/current-system/kernel))/.build/linux-*");
-            chomp $kernelDir;
-            my $coverageDir = "/tmp/xchg/coverage-data/$kernelDir";
-
-            # Copy all the *.gcda files.
-            $vm->execute("for d in $gcovDir/nix/store/*/.build/linux-*; do for i in \$(cd \$d && find -name '*.gcda'); do echo \$i; mkdir -p $coverageDir/\$(dirname \$i); cp -v \$d/\$i $coverageDir/\$i; done; done");
-        }
-    });
-
-    $log->nest("syncing", sub {
-        foreach my $vm (values %vms) {
-            next unless $vm->isUp();
-            $vm->execute("sync");
-        }
-    });
-
-    if ($nrTests != 0) {
-        $log->log("$nrSucceeded out of $nrTests tests succeeded",
-            ($nrSucceeded < $nrTests ? { error => 1 } : { }));
-    }
-}
-
-
-# Create an empty raw virtual disk with the given name and size (in
-# MiB).
-sub createDisk {
-    my ($name, $size) = @_;
-    system("qemu-img create -f raw $name ${size}M") == 0
-        or die "cannot create image of size $size";
-}
-
-
-END {
-    $log->nest("cleaning up", sub {
-        foreach my $vm (values %vms) {
-            if ($vm->{pid}) {
-                $log->log("killing " . $vm->{name} . " (pid " . $vm->{pid} . ")");
-                kill 9, $vm->{pid};
-            }
-        }
-    });
-    $log->close();
-}
-
-my $now1 = clock_gettime(CLOCK_MONOTONIC);
-
-runTests;
-
-my $now2 = clock_gettime(CLOCK_MONOTONIC);
-
-printf STDERR "test script finished in %.2fs\n", $now2 - $now1;
-
-exit ($nrSucceeded < $nrTests ? 1 : 0);
diff --git a/nixos/lib/test-driver/test-driver.py b/nixos/lib/test-driver/test-driver.py
index e7b05968b0796..156392ad1e320 100644
--- a/nixos/lib/test-driver/test-driver.py
+++ b/nixos/lib/test-driver/test-driver.py
@@ -3,7 +3,10 @@ from contextlib import contextmanager, _GeneratorContextManager
 from queue import Queue, Empty
 from typing import Tuple, Any, Callable, Dict, Iterator, Optional, List
 from xml.sax.saxutils import XMLGenerator
+import queue
+import io
 import _thread
+import argparse
 import atexit
 import base64
 import codecs
@@ -19,6 +22,7 @@ import subprocess
 import sys
 import tempfile
 import time
+import traceback
 import unicodedata
 
 CHAR_TO_KEY = {
@@ -213,7 +217,7 @@ class Machine:
                 match = re.search("run-(.+)-vm$", cmd)
                 if match:
                     self.name = match.group(1)
-
+        self.logger = args["log"]
         self.script = args.get("startCommand", self.create_startcommand(args))
 
         tmp_dir = os.environ.get("TMPDIR", tempfile.gettempdir())
@@ -223,7 +227,10 @@ class Machine:
             os.makedirs(path, mode=0o700, exist_ok=True)
             return path
 
-        self.state_dir = create_dir("vm-state-{}".format(self.name))
+        self.state_dir = os.path.join(tmp_dir, f"vm-state-{self.name}")
+        if not args.get("keepVmState", False):
+            self.cleanup_statedir()
+        os.makedirs(self.state_dir, mode=0o700, exist_ok=True)
         self.shared_dir = create_dir("shared-xchg")
 
         self.booted = False
@@ -231,7 +238,6 @@ class Machine:
         self.pid: Optional[int] = None
         self.socket = None
         self.monitor: Optional[socket.socket] = None
-        self.logger: Logger = args["log"]
         self.allow_reboot = args.get("allowReboot", False)
 
     @staticmethod
@@ -420,15 +426,18 @@ class Machine:
                 output += out
         return output
 
-    def fail(self, *commands: str) -> None:
+    def fail(self, *commands: str) -> str:
         """Execute each command and check that it fails."""
+        output = ""
         for command in commands:
             with self.nested("must fail: {}".format(command)):
-                status, output = self.execute(command)
+                (status, out) = self.execute(command)
                 if status == 0:
                     raise Exception(
                         "command `{}` unexpectedly succeeded".format(command)
                     )
+                output += out
+        return output
 
     def wait_until_succeeds(self, command: str) -> str:
         """Wait until a command returns success and return its output.
@@ -671,6 +680,22 @@ class Machine:
         with self.nested("waiting for {} to appear on screen".format(regex)):
             retry(screen_matches)
 
+    def wait_for_console_text(self, regex: str) -> None:
+        self.log("waiting for {} to appear on console".format(regex))
+        # Buffer the console output, this is needed
+        # to match multiline regexes.
+        console = io.StringIO()
+        while True:
+            try:
+                console.write(self.last_lines.get())
+            except queue.Empty:
+                self.sleep(1)
+                continue
+            console.seek(0)
+            matches = re.search(regex, console.read())
+            if matches is not None:
+                return
+
     def send_key(self, key: str) -> None:
         key = CHAR_TO_KEY.get(key, key)
         self.send_monitor_command("sendkey {}".format(key))
@@ -734,11 +759,16 @@ class Machine:
         self.monitor, _ = self.monitor_socket.accept()
         self.shell, _ = self.shell_socket.accept()
 
+        # Store last serial console lines for use
+        # of wait_for_console_text
+        self.last_lines: Queue = Queue()
+
         def process_serial_output() -> None:
             assert self.process.stdout is not None
             for _line in self.process.stdout:
                 # Ignore undecodable bytes that may occur in boot menus
                 line = _line.decode(errors="ignore").replace("\r", "").rstrip()
+                self.last_lines.put(line)
                 eprint("{} # {}".format(self.name, line))
                 self.logger.enqueue({"msg": line, "machine": self.name})
 
@@ -751,6 +781,12 @@ class Machine:
 
         self.log("QEMU running (pid {})".format(self.pid))
 
+    def cleanup_statedir(self) -> None:
+        if os.path.isdir(self.state_dir):
+            shutil.rmtree(self.state_dir)
+            self.logger.log(f"deleting VM state directory {self.state_dir}")
+            self.logger.log("if you want to keep the VM state, pass --keep-vm-state")
+
     def shutdown(self) -> None:
         if not self.booted:
             return
@@ -807,7 +843,8 @@ class Machine:
             retry(window_is_visible)
 
     def sleep(self, secs: int) -> None:
-        time.sleep(secs)
+        # We want to sleep in *guest* time, not *host* time.
+        self.succeed(f"sleep {secs}")
 
     def forward_port(self, host_port: int = 8080, guest_port: int = 80) -> None:
         """Forward a TCP port on the host to a TCP port on the guest.
@@ -863,7 +900,8 @@ def run_tests() -> None:
             try:
                 exec(tests, globals())
             except Exception as e:
-                eprint("error: {}".format(str(e)))
+                eprint("error: ")
+                traceback.print_exc()
                 sys.exit(1)
     else:
         ptpython.repl.embed(locals(), globals())
@@ -889,6 +927,15 @@ def subtest(name: str) -> Iterator[None]:
 
 
 if __name__ == "__main__":
+    arg_parser = argparse.ArgumentParser()
+    arg_parser.add_argument(
+        "-K",
+        "--keep-vm-state",
+        help="re-use a VM state coming from a previous run",
+        action="store_true",
+    )
+    (cli_args, vm_scripts) = arg_parser.parse_known_args()
+
     log = Logger()
 
     vlan_nrs = list(dict.fromkeys(os.environ.get("VLANS", "").split()))
@@ -896,8 +943,10 @@ if __name__ == "__main__":
     for nr, vde_socket, _, _ in vde_sockets:
         os.environ["QEMU_VDE_SOCKET_{}".format(nr)] = vde_socket
 
-    vm_scripts = sys.argv[1:]
-    machines = [create_machine({"startCommand": s}) for s in vm_scripts]
+    machines = [
+        create_machine({"startCommand": s, "keepVmState": cli_args.keep_vm_state})
+        for s in vm_scripts
+    ]
     machine_eval = [
         "{0} = machines[{1}]".format(m.name, idx) for idx, m in enumerate(machines)
     ]
@@ -911,7 +960,6 @@ if __name__ == "__main__":
                     continue
                 log.log("killing {} (pid {})".format(machine.name, machine.pid))
                 machine.process.kill()
-
             for _, _, process, _ in vde_sockets:
                 process.terminate()
         log.close()
diff --git a/nixos/lib/testing-python.nix b/nixos/lib/testing-python.nix
index 123323711a7ca..498f97336c029 100644
--- a/nixos/lib/testing-python.nix
+++ b/nixos/lib/testing-python.nix
@@ -4,10 +4,12 @@
 , minimal ? false
   # Ignored
 , config ? {}
+  # !!! See comment about args in lib/modules.nix
+, specialArgs ? {}
   # Modules to add to each VM
 , extraConfigurations ? [] }:
 
-with import ./build-vms.nix { inherit system pkgs minimal extraConfigurations; };
+with import ./build-vms.nix { inherit system pkgs minimal specialArgs extraConfigurations; };
 with pkgs;
 
 rec {
@@ -63,18 +65,12 @@ rec {
           mkdir -p $out
 
           LOGFILE=/dev/null tests='exec(os.environ["testScript"])' ${driver}/bin/nixos-test-driver
-
-          for i in */xchg/coverage-data; do
-            mkdir -p $out/coverage-data
-            mv $i $out/coverage-data/$(dirname $(dirname $i))
-          done
         '';
     };
 
 
   makeTest =
     { testScript
-    , makeCoverageReport ? false
     , enableOCR ? false
     , name ? "unnamed"
     # Skip linting (mainly intended for faster dev cycles)
@@ -114,7 +110,7 @@ rec {
 
       imagemagick_tiff = imagemagick_light.override { inherit libtiff; };
 
-      # Generate onvenience wrappers for running the test driver
+      # Generate convenience wrappers for running the test driver
       # interactively with the specified network, and for starting the
       # VMs from the command line.
       driver = let warn = if skipLint then lib.warn "Linting is disabled!" else lib.id; in warn (runCommand testDriverName
@@ -153,7 +149,6 @@ rec {
       };
 
       test = passMeta (runTests driver);
-      report = passMeta (releaseTools.gcovReport { coverageRuns = [ test ]; });
 
       nodeNames = builtins.attrNames nodes;
       invalidNodeNames = lib.filter
@@ -169,7 +164,7 @@ rec {
           Please stick to alphanumeric chars and underscores as separation.
         ''
       else
-        (if makeCoverageReport then report else test) // {
+        test // {
           inherit nodes driver test;
         };
 
diff --git a/nixos/lib/testing.nix b/nixos/lib/testing.nix
deleted file mode 100644
index 5c784c2f0abe4..0000000000000
--- a/nixos/lib/testing.nix
+++ /dev/null
@@ -1,258 +0,0 @@
-{ system
-, pkgs ? import ../.. { inherit system config; }
-  # Use a minimal kernel?
-, minimal ? false
-  # Ignored
-, config ? {}
-  # Modules to add to each VM
-, extraConfigurations ? [] }:
-
-with import ./build-vms.nix { inherit system pkgs minimal extraConfigurations; };
-with pkgs;
-
-rec {
-
-  inherit pkgs;
-
-
-  testDriver = lib.warn ''
-    Perl VM tests are deprecated and will be removed for 20.09.
-    Please update your tests to use the python test driver.
-    See https://github.com/NixOS/nixpkgs/pull/71684 for details.
-  '' stdenv.mkDerivation {
-    name = "nixos-test-driver";
-
-    buildInputs = [ makeWrapper perl ];
-
-    dontUnpack = true;
-
-    preferLocalBuild = true;
-
-    installPhase =
-      ''
-        mkdir -p $out/bin
-        cp ${./test-driver/test-driver.pl} $out/bin/nixos-test-driver
-        chmod u+x $out/bin/nixos-test-driver
-
-        libDir=$out/${perl.libPrefix}
-        mkdir -p $libDir
-        cp ${./test-driver/Machine.pm} $libDir/Machine.pm
-        cp ${./test-driver/Logger.pm} $libDir/Logger.pm
-
-        wrapProgram $out/bin/nixos-test-driver \
-          --prefix PATH : "${lib.makeBinPath [ qemu_test vde2 netpbm coreutils ]}" \
-          --prefix PERL5LIB : "${with perlPackages; makePerlPath [ TermReadLineGnu XMLWriter IOTty FileSlurp ]}:$out/${perl.libPrefix}"
-      '';
-  };
-
-
-  # Run an automated test suite in the given virtual network.
-  # `driver' is the script that runs the network.
-  runTests = driver:
-    stdenv.mkDerivation {
-      name = "vm-test-run-${driver.testName}";
-
-      requiredSystemFeatures = [ "kvm" "nixos-test" ];
-
-      buildCommand =
-        ''
-          mkdir -p $out
-
-          LOGFILE=/dev/null tests='eval $ENV{testScript}; die $@ if $@;' ${driver}/bin/nixos-test-driver
-
-          for i in */xchg/coverage-data; do
-            mkdir -p $out/coverage-data
-            mv $i $out/coverage-data/$(dirname $(dirname $i))
-          done
-        '';
-    };
-
-
-  makeTest =
-    { testScript
-    , makeCoverageReport ? false
-    , enableOCR ? false
-    , name ? "unnamed"
-    , ...
-    } @ t:
-
-    let
-      # A standard store path to the vm monitor is built like this:
-      #   /tmp/nix-build-vm-test-run-$name.drv-0/vm-state-machine/monitor
-      # The max filename length of a unix domain socket is 108 bytes.
-      # This means $name can at most be 50 bytes long.
-      maxTestNameLen = 50;
-      testNameLen = builtins.stringLength name;
-
-      testDriverName = with builtins;
-        if testNameLen > maxTestNameLen then
-          abort ("The name of the test '${name}' must not be longer than ${toString maxTestNameLen} " +
-            "it's currently ${toString testNameLen} characters long.")
-        else
-          "nixos-test-driver-${name}";
-
-      nodes = buildVirtualNetwork (
-        t.nodes or (if t ? machine then { machine = t.machine; } else { }));
-
-      testScript' =
-        # Call the test script with the computed nodes.
-        if lib.isFunction testScript
-        then testScript { inherit nodes; }
-        else testScript;
-
-      vlans = map (m: m.config.virtualisation.vlans) (lib.attrValues nodes);
-
-      vms = map (m: m.config.system.build.vm) (lib.attrValues nodes);
-
-      ocrProg = tesseract4.override { enableLanguages = [ "eng" ]; };
-
-      imagemagick_tiff = imagemagick_light.override { inherit libtiff; };
-
-      # Generate onvenience wrappers for running the test driver
-      # interactively with the specified network, and for starting the
-      # VMs from the command line.
-      driver = runCommand testDriverName
-        { buildInputs = [ makeWrapper];
-          testScript = testScript';
-          preferLocalBuild = true;
-          testName = name;
-        }
-        ''
-          mkdir -p $out/bin
-          echo "$testScript" > $out/test-script
-          ln -s ${testDriver}/bin/nixos-test-driver $out/bin/
-          vms=($(for i in ${toString vms}; do echo $i/bin/run-*-vm; done))
-          wrapProgram $out/bin/nixos-test-driver \
-            --add-flags "''${vms[*]}" \
-            ${lib.optionalString enableOCR
-              "--prefix PATH : '${ocrProg}/bin:${imagemagick_tiff}/bin'"} \
-            --run "export testScript=\"\$(cat $out/test-script)\"" \
-            --set VLANS '${toString vlans}'
-          ln -s ${testDriver}/bin/nixos-test-driver $out/bin/nixos-run-vms
-          wrapProgram $out/bin/nixos-run-vms \
-            --add-flags "''${vms[*]}" \
-            ${lib.optionalString enableOCR "--prefix PATH : '${ocrProg}/bin'"} \
-            --set tests 'startAll; joinAll;' \
-            --set VLANS '${toString vlans}' \
-            ${lib.optionalString (builtins.length vms == 1) "--set USE_SERIAL 1"}
-        ''; # "
-
-      passMeta = drv: drv // lib.optionalAttrs (t ? meta) {
-        meta = (drv.meta or {}) // t.meta;
-      };
-
-      test = passMeta (runTests driver);
-      report = passMeta (releaseTools.gcovReport { coverageRuns = [ test ]; });
-
-      nodeNames = builtins.attrNames nodes;
-      invalidNodeNames = lib.filter
-        (node: builtins.match "^[A-z_][A-z0-9_]+$" node == null) nodeNames;
-
-    in
-      if lib.length invalidNodeNames > 0 then
-        throw ''
-          Cannot create machines out of (${lib.concatStringsSep ", " invalidNodeNames})!
-          All machines are referenced as perl variables in the testing framework which will break the
-          script when special characters are used.
-
-          Please stick to alphanumeric chars and underscores as separation.
-        ''
-      else
-        (if makeCoverageReport then report else test) // {
-          inherit nodes driver test;
-        };
-
-  runInMachine =
-    { drv
-    , machine
-    , preBuild ? ""
-    , postBuild ? ""
-    , ... # ???
-    }:
-    let
-      vm = buildVM { }
-        [ machine
-          { key = "run-in-machine";
-            networking.hostName = "client";
-            nix.readOnlyStore = false;
-            virtualisation.writableStore = false;
-          }
-        ];
-
-      buildrunner = writeText "vm-build" ''
-        source $1
-
-        ${coreutils}/bin/mkdir -p $TMPDIR
-        cd $TMPDIR
-
-        exec $origBuilder $origArgs
-      '';
-
-      testScript = ''
-        startAll;
-        $client->waitForUnit("multi-user.target");
-        ${preBuild}
-        $client->succeed("env -i ${bash}/bin/bash ${buildrunner} /tmp/xchg/saved-env >&2");
-        ${postBuild}
-        $client->succeed("sync"); # flush all data before pulling the plug
-      '';
-
-      vmRunCommand = writeText "vm-run" ''
-        xchg=vm-state-client/xchg
-        ${coreutils}/bin/mkdir $out
-        ${coreutils}/bin/mkdir -p $xchg
-
-        for i in $passAsFile; do
-          i2=''${i}Path
-          _basename=$(${coreutils}/bin/basename ''${!i2})
-          ${coreutils}/bin/cp ''${!i2} $xchg/$_basename
-          eval $i2=/tmp/xchg/$_basename
-          ${coreutils}/bin/ls -la $xchg
-        done
-
-        unset i i2 _basename
-        export | ${gnugrep}/bin/grep -v '^xchg=' > $xchg/saved-env
-        unset xchg
-
-        export tests='${testScript}'
-        ${testDriver}/bin/nixos-test-driver ${vm.config.system.build.vm}/bin/run-*-vm
-      ''; # */
-
-    in
-      lib.overrideDerivation drv (attrs: {
-        requiredSystemFeatures = [ "kvm" ];
-        builder = "${bash}/bin/sh";
-        args = ["-e" vmRunCommand];
-        origArgs = attrs.args;
-        origBuilder = attrs.builder;
-      });
-
-
-  runInMachineWithX = { require ? [], ... } @ args:
-    let
-      client =
-        { ... }:
-        {
-          inherit require;
-          imports = [
-            ../tests/common/auto.nix
-          ];
-          virtualisation.memorySize = 1024;
-          services.xserver.enable = true;
-          test-support.displayManager.auto.enable = true;
-          services.xserver.displayManager.defaultSession = "none+icewm";
-          services.xserver.windowManager.icewm.enable = true;
-        };
-    in
-      runInMachine ({
-        machine = client;
-        preBuild =
-          ''
-            $client->waitForX;
-          '';
-      } // args);
-
-
-  simpleTest = as: (makeTest as).test;
-
-}
diff --git a/nixos/lib/utils.nix b/nixos/lib/utils.nix
index 21f4c7c6988ff..543c8a8882ea6 100644
--- a/nixos/lib/utils.nix
+++ b/nixos/lib/utils.nix
@@ -2,9 +2,11 @@ pkgs: with pkgs.lib;
 
 rec {
 
-  # Check whenever fileSystem is needed for boot
-  fsNeededForBoot = fs: fs.neededForBoot
-                     || elem fs.mountPoint [ "/" "/nix" "/nix/store" "/var" "/var/log" "/var/lib" "/etc" ];
+  # Check whenever fileSystem is needed for boot.  NOTE: Make sure
+  # pathsNeededForBoot is closed under the parent relationship, i.e. if /a/b/c
+  # is in the list, put /a and /a/b in as well.
+  pathsNeededForBoot = [ "/" "/nix" "/nix/store" "/var" "/var/log" "/var/lib" "/etc" ];
+  fsNeededForBoot = fs: fs.neededForBoot || elem fs.mountPoint pathsNeededForBoot;
 
   # Check whenever `b` depends on `a` as a fileSystem
   fsBefore = a: b: a.mountPoint == b.device
diff --git a/nixos/maintainers/scripts/azure-new/.gitignore b/nixos/maintainers/scripts/azure-new/.gitignore
index 26905a8623473..9271abf14a0f0 100644
--- a/nixos/maintainers/scripts/azure-new/.gitignore
+++ b/nixos/maintainers/scripts/azure-new/.gitignore
@@ -1 +1 @@
-azure
\ No newline at end of file
+azure
diff --git a/nixos/maintainers/scripts/azure-new/README.md b/nixos/maintainers/scripts/azure-new/README.md
index 20e81c44ce5db..e5b69dacec08c 100644
--- a/nixos/maintainers/scripts/azure-new/README.md
+++ b/nixos/maintainers/scripts/azure-new/README.md
@@ -20,7 +20,7 @@ $ ./upload-image.sh ./examples/basic/image.nix
 + nix-build ./examples/basic/image.nix --out-link azure
 /nix/store/qdpzknpskzw30vba92mb24xzll1dqsmd-azure-image
 ...
-95.5 %, 0 Done, 0 Failed, 1 Pending, 0 Skipped, 1 Total, 2-sec Throughput (Mb/s): 932.9565 
+95.5 %, 0 Done, 0 Failed, 1 Pending, 0 Skipped, 1 Total, 2-sec Throughput (Mb/s): 932.9565
 ...
 /subscriptions/aff271ee-e9be-4441-b9bb-42f5af4cbaeb/resourceGroups/nixos-images/providers/Microsoft.Compute/images/azure-image-todo-makethisbetter
 ```
diff --git a/nixos/maintainers/scripts/azure-new/upload-image.sh b/nixos/maintainers/scripts/azure-new/upload-image.sh
index 1466dcd1f0a2e..143afbd7f962e 100755
--- a/nixos/maintainers/scripts/azure-new/upload-image.sh
+++ b/nixos/maintainers/scripts/azure-new/upload-image.sh
@@ -37,8 +37,8 @@ if ! az disk show -g "${group}" -n "${img_name}" &>/dev/null; then
   )"
 
   azcopy copy "${img_file}" "${sasurl}" \
-    --blob-type PageBlob 
-    
+    --blob-type PageBlob
+
   az disk revoke-access \
     --resource-group "${group}" \
     --name "${img_name}"
diff --git a/nixos/maintainers/scripts/ec2/amazon-image.nix b/nixos/maintainers/scripts/ec2/amazon-image.nix
index 36f3e7af873d2..b09f4ca47a3fc 100644
--- a/nixos/maintainers/scripts/ec2/amazon-image.nix
+++ b/nixos/maintainers/scripts/ec2/amazon-image.nix
@@ -63,8 +63,8 @@ in {
     fsType = "ext4";
     configFile = pkgs.writeText "configuration.nix"
       ''
-        {
-          imports = [ <nixpkgs/nixos/modules/virtualisation/amazon-image.nix> ];
+        { modulesPath, ... }: {
+          imports = [ "''${modulesPath}/virtualisation/amazon-image.nix" ];
           ${optionalString config.ec2.hvm ''
             ec2.hvm = true;
           ''}
diff --git a/nixos/maintainers/scripts/ec2/create-amis.sh b/nixos/maintainers/scripts/ec2/create-amis.sh
index 145eb49ced7a3..89e24f2ccfd95 100755
--- a/nixos/maintainers/scripts/ec2/create-amis.sh
+++ b/nixos/maintainers/scripts/ec2/create-amis.sh
@@ -29,7 +29,7 @@ log() {
     echo "$@" >&2
 }
 
-if [ -z "$1" ]; then
+if [ "$#" -ne 1 ]; then
     log "Usage: ./upload-amazon-image.sh IMAGE_OUTPUT"
     exit 1
 fi
diff --git a/nixos/modules/config/appstream.nix b/nixos/modules/config/appstream.nix
index 483ac9c3cd762..a72215c2f5613 100644
--- a/nixos/modules/config/appstream.nix
+++ b/nixos/modules/config/appstream.nix
@@ -7,18 +7,18 @@ with lib;
       type = types.bool;
       default = true;
       description = ''
-        Whether to install files to support the 
+        Whether to install files to support the
         <link xlink:href="https://www.freedesktop.org/software/appstream/docs/index.html">AppStream metadata specification</link>.
       '';
     };
   };
 
   config = mkIf config.appstream.enable {
-    environment.pathsToLink = [ 
+    environment.pathsToLink = [
       # per component metadata
-      "/share/metainfo" 
+      "/share/metainfo"
       # legacy path for above
-      "/share/appdata" 
+      "/share/appdata"
     ];
   };
 
diff --git a/nixos/modules/config/fonts/fontconfig-penultimate.nix b/nixos/modules/config/fonts/fontconfig-penultimate.nix
deleted file mode 100644
index 7e311a21acf69..0000000000000
--- a/nixos/modules/config/fonts/fontconfig-penultimate.nix
+++ /dev/null
@@ -1,292 +0,0 @@
-{ config, pkgs, lib, ... }:
-
-with lib;
-
-let
-  cfg = config.fonts.fontconfig;
-
-  fcBool = x: "<bool>" + (boolToString x) + "</bool>";
-
-  # back-supported fontconfig version and package
-  # version is used for font cache generation
-  supportVersion = "210";
-  supportPkg     = pkgs."fontconfig_${supportVersion}";
-
-  # latest fontconfig version and package
-  # version is used for configuration folder name, /etc/fonts/VERSION/
-  # note: format differs from supportVersion and can not be used with makeCacheConf
-  latestVersion  = pkgs.fontconfig.configVersion;
-  latestPkg      = pkgs.fontconfig;
-
-  # supported version fonts.conf
-  supportFontsConf = pkgs.makeFontsConf { fontconfig = supportPkg; fontDirectories = config.fonts.fonts; };
-
-  # configuration file to read fontconfig cache
-  # version dependent
-  # priority 0
-  cacheConfSupport = makeCacheConf { version = supportVersion; };
-  cacheConfLatest  = makeCacheConf {};
-
-  # generate the font cache setting file for a fontconfig version
-  # use latest when no version is passed
-  makeCacheConf = { version ? null }:
-    let
-      fcPackage = if version == null
-                  then "fontconfig"
-                  else "fontconfig_${version}";
-      makeCache = fontconfig: pkgs.makeFontsCache { inherit fontconfig; fontDirectories = config.fonts.fonts; };
-      cache     = makeCache pkgs.${fcPackage};
-      cache32   = makeCache pkgs.pkgsi686Linux.${fcPackage};
-    in
-    pkgs.writeText "fc-00-nixos-cache.conf" ''
-      <?xml version='1.0'?>
-      <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
-      <fontconfig>
-        <!-- Font directories -->
-        ${concatStringsSep "\n" (map (font: "<dir>${font}</dir>") config.fonts.fonts)}
-        <!-- Pre-generated font caches -->
-        <cachedir>${cache}</cachedir>
-        ${optionalString (pkgs.stdenv.isx86_64 && cfg.cache32Bit) ''
-          <cachedir>${cache32}</cachedir>
-        ''}
-      </fontconfig>
-    '';
-
-  # local configuration file
-  localConf = pkgs.writeText "fc-local.conf" cfg.localConf;
-
-  # rendering settings configuration files
-  # priority 10
-  hintingConf = pkgs.writeText "fc-10-hinting.conf" ''
-    <?xml version='1.0'?>
-    <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
-    <fontconfig>
-
-      <!-- Default rendering settings -->
-      <match target="pattern">
-        <edit mode="append" name="hinting">
-          ${fcBool cfg.hinting.enable}
-        </edit>
-        <edit mode="append" name="autohint">
-          ${fcBool cfg.hinting.autohint}
-        </edit>
-        <edit mode="append" name="hintstyle">
-          <const>hintslight</const>
-        </edit>
-      </match>
-
-    </fontconfig>
-  '';
-
-  antialiasConf = pkgs.writeText "fc-10-antialias.conf" ''
-    <?xml version='1.0'?>
-    <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
-    <fontconfig>
-
-      <!-- Default rendering settings -->
-      <match target="pattern">
-        <edit mode="append" name="antialias">
-          ${fcBool cfg.antialias}
-        </edit>
-      </match>
-
-    </fontconfig>
-  '';
-
-  subpixelConf = pkgs.writeText "fc-10-subpixel.conf" ''
-    <?xml version='1.0'?>
-    <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
-    <fontconfig>
-
-      <!-- Default rendering settings -->
-      <match target="pattern">
-        <edit mode="append" name="rgba">
-          <const>${cfg.subpixel.rgba}</const>
-        </edit>
-        <edit mode="append" name="lcdfilter">
-          <const>lcd${cfg.subpixel.lcdfilter}</const>
-        </edit>
-      </match>
-
-    </fontconfig>
-  '';
-
-  dpiConf = pkgs.writeText "fc-11-dpi.conf" ''
-    <?xml version='1.0'?>
-    <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
-    <fontconfig>
-
-      <match target="pattern">
-        <edit name="dpi" mode="assign">
-          <double>${toString cfg.dpi}</double>
-        </edit>
-      </match>
-
-    </fontconfig>
-  '';
-
-  # default fonts configuration file
-  # priority 52
-  defaultFontsConf =
-    let genDefault = fonts: name:
-      optionalString (fonts != []) ''
-        <alias>
-          <family>${name}</family>
-          <prefer>
-          ${concatStringsSep ""
-          (map (font: ''
-            <family>${font}</family>
-          '') fonts)}
-          </prefer>
-        </alias>
-      '';
-    in
-    pkgs.writeText "fc-52-nixos-default-fonts.conf" ''
-    <?xml version='1.0'?>
-    <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
-    <fontconfig>
-
-      <!-- Default fonts -->
-      ${genDefault cfg.defaultFonts.sansSerif "sans-serif"}
-
-      ${genDefault cfg.defaultFonts.serif     "serif"}
-
-      ${genDefault cfg.defaultFonts.monospace "monospace"}
-
-    </fontconfig>
-  '';
-
-  # reject Type 1 fonts
-  # priority 53
-  rejectType1 = pkgs.writeText "fc-53-nixos-reject-type1.conf" ''
-    <?xml version="1.0"?>
-    <!DOCTYPE fontconfig SYSTEM "fonts.dtd">
-    <fontconfig>
-
-    <!-- Reject Type 1 fonts -->
-    <selectfont>
-      <rejectfont>
-        <pattern>
-          <patelt name="fontformat"><string>Type 1</string></patelt>
-        </pattern>
-      </rejectfont>
-    </selectfont>
-
-    </fontconfig>
-  '';
-
-  # The configuration to be included in /etc/font/
-  penultimateConf = pkgs.runCommand "fontconfig-penultimate-conf" {
-    preferLocalBuild = true;
-  } ''
-    support_folder=$out/etc/fonts/conf.d
-    latest_folder=$out/etc/fonts/${latestVersion}/conf.d
-
-    mkdir -p $support_folder
-    mkdir -p $latest_folder
-
-    # fonts.conf
-    ln -s ${supportFontsConf} $support_folder/../fonts.conf
-    ln -s ${latestPkg.out}/etc/fonts/fonts.conf \
-          $latest_folder/../fonts.conf
-
-    # fontconfig-penultimate various configuration files
-    ln -s ${pkgs.fontconfig-penultimate}/etc/fonts/conf.d/*.conf \
-          $support_folder
-    ln -s ${pkgs.fontconfig-penultimate}/etc/fonts/conf.d/*.conf \
-          $latest_folder
-
-    ln -s ${cacheConfSupport} $support_folder/00-nixos-cache.conf
-    ln -s ${cacheConfLatest}  $latest_folder/00-nixos-cache.conf
-
-    rm $support_folder/10-antialias.conf $latest_folder/10-antialias.conf
-    ln -s ${antialiasConf} $support_folder/10-antialias.conf
-    ln -s ${antialiasConf} $latest_folder/10-antialias.conf
-
-    rm $support_folder/10-hinting.conf $latest_folder/10-hinting.conf
-    ln -s ${hintingConf} $support_folder/10-hinting.conf
-    ln -s ${hintingConf} $latest_folder/10-hinting.conf
-
-    ${optionalString cfg.useEmbeddedBitmaps ''
-    rm $support_folder/10-no-embedded-bitmaps.conf
-    rm $latest_folder/10-no-embedded-bitmaps.conf
-    ''}
-
-    rm $support_folder/10-subpixel.conf $latest_folder/10-subpixel.conf
-    ln -s ${subpixelConf} $support_folder/10-subpixel.conf
-    ln -s ${subpixelConf} $latest_folder/10-subpixel.conf
-
-    ${optionalString (cfg.dpi != 0) ''
-    ln -s ${dpiConf} $support_folder/11-dpi.conf
-    ln -s ${dpiConf} $latest_folder/11-dpi.conf
-    ''}
-
-    # 50-user.conf
-    ${optionalString (!cfg.includeUserConf) ''
-    rm $support_folder/50-user.conf
-    rm $latest_folder/50-user.conf
-    ''}
-
-    # 51-local.conf
-    rm $latest_folder/51-local.conf
-    substitute \
-      ${pkgs.fontconfig-penultimate}/etc/fonts/conf.d/51-local.conf \
-      $latest_folder/51-local.conf \
-      --replace local.conf /etc/fonts/${latestVersion}/local.conf
-
-    # local.conf (indirect priority 51)
-    ${optionalString (cfg.localConf != "") ''
-    ln -s ${localConf}        $support_folder/../local.conf
-    ln -s ${localConf}        $latest_folder/../local.conf
-    ''}
-
-    # 52-nixos-default-fonts.conf
-    ln -s ${defaultFontsConf} $support_folder/52-nixos-default-fonts.conf
-    ln -s ${defaultFontsConf} $latest_folder/52-nixos-default-fonts.conf
-
-    # 53-no-bitmaps.conf
-    ${optionalString cfg.allowBitmaps ''
-    rm $support_folder/53-no-bitmaps.conf
-    rm $latest_folder/53-no-bitmaps.conf
-    ''}
-
-    ${optionalString (!cfg.allowType1) ''
-    # 53-nixos-reject-type1.conf
-    ln -s ${rejectType1} $support_folder/53-nixos-reject-type1.conf
-    ln -s ${rejectType1} $latest_folder/53-nixos-reject-type1.conf
-    ''}
-  '';
-
-in
-{
-
-  options = {
-
-    fonts = {
-
-      fontconfig = {
-
-        penultimate = {
-          enable = mkOption {
-            type = types.bool;
-            default = false;
-            description = ''
-              Enable fontconfig-penultimate settings to supplement the
-              NixOS defaults by providing per-font rendering defaults and
-              metric aliases.
-            '';
-          };
-        };
-
-      };
-    };
-
-  };
-
-  config = mkIf (config.fonts.fontconfig.enable && config.fonts.fontconfig.penultimate.enable) {
-
-    fonts.fontconfig.confPackages = [ penultimateConf ];
-
-  };
-
-}
diff --git a/nixos/modules/config/fonts/fontconfig.nix b/nixos/modules/config/fonts/fontconfig.nix
index ac2a024eaa894..5b681ca59464d 100644
--- a/nixos/modules/config/fonts/fontconfig.nix
+++ b/nixos/modules/config/fonts/fontconfig.nix
@@ -1,11 +1,6 @@
 /*
 
-NixOS support 2 fontconfig versions, "support" and "latest".
-
-- "latest" refers to default fontconfig package (pkgs.fontconfig).
-  configuration files are linked to /etc/fonts/VERSION/conf.d/
-- "support" refers to supportPkg (pkgs."fontconfig_${supportVersion}").
-  configuration files are linked to /etc/fonts/conf.d/
+Configuration files are linked to /etc/fonts/conf.d/
 
 This module generates a package containing configuration files and link it in /etc/fonts.
 
@@ -22,44 +17,25 @@ let
   cfg = config.fonts.fontconfig;
 
   fcBool = x: "<bool>" + (boolToString x) + "</bool>";
-
-  # back-supported fontconfig version and package
-  # version is used for font cache generation
-  supportVersion = "210";
-  supportPkg     = pkgs."fontconfig_${supportVersion}";
-
-  # latest fontconfig version and package
-  # version is used for configuration folder name, /etc/fonts/VERSION/
-  # note: format differs from supportVersion and can not be used with makeCacheConf
-  latestVersion  = pkgs.fontconfig.configVersion;
-  latestPkg      = pkgs.fontconfig;
-
-  # supported version fonts.conf
-  supportFontsConf = pkgs.makeFontsConf { fontconfig = supportPkg; fontDirectories = config.fonts.fonts; };
+  pkg = pkgs.fontconfig;
 
   # configuration file to read fontconfig cache
-  # version dependent
   # priority 0
-  cacheConfSupport = makeCacheConf { version = supportVersion; };
-  cacheConfLatest  = makeCacheConf {};
+  cacheConf  = makeCacheConf {};
 
-  # generate the font cache setting file for a fontconfig version
-  # use latest when no version is passed
+  # generate the font cache setting file
   # When cross-compiling, we can’t generate the cache, so we skip the
   # <cachedir> part. fontconfig still works but is a little slower in
   # looking things up.
-  makeCacheConf = { version ? null }:
+  makeCacheConf = { }:
     let
-      fcPackage = if version == null
-                  then "fontconfig"
-                  else "fontconfig_${version}";
       makeCache = fontconfig: pkgs.makeFontsCache { inherit fontconfig; fontDirectories = config.fonts.fonts; };
-      cache     = makeCache pkgs.${fcPackage};
-      cache32   = makeCache pkgs.pkgsi686Linux.${fcPackage};
+      cache     = makeCache pkgs.fontconfig;
+      cache32   = makeCache pkgs.pkgsi686Linux.fontconfig;
     in
     pkgs.writeText "fc-00-nixos-cache.conf" ''
       <?xml version='1.0'?>
-      <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
+      <!DOCTYPE fontconfig SYSTEM 'urn:fontconfig:fonts.dtd'>
       <fontconfig>
         <!-- Font directories -->
         ${concatStringsSep "\n" (map (font: "<dir>${font}</dir>") config.fonts.fonts)}
@@ -77,7 +53,7 @@ let
   # priority 10
   renderConf = pkgs.writeText "fc-10-nixos-rendering.conf" ''
     <?xml version='1.0'?>
-    <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
+    <!DOCTYPE fontconfig SYSTEM 'urn:fontconfig:fonts.dtd'>
     <fontconfig>
 
       <!-- Default rendering settings -->
@@ -134,7 +110,7 @@ let
     in
     pkgs.writeText "fc-52-nixos-default-fonts.conf" ''
     <?xml version='1.0'?>
-    <!DOCTYPE fontconfig SYSTEM 'fonts.dtd'>
+    <!DOCTYPE fontconfig SYSTEM 'urn:fontconfig:fonts.dtd'>
     <fontconfig>
 
       <!-- Default fonts -->
@@ -153,7 +129,7 @@ let
   # priority 53
   rejectBitmaps = pkgs.writeText "fc-53-no-bitmaps.conf" ''
     <?xml version="1.0"?>
-    <!DOCTYPE fontconfig SYSTEM "fonts.dtd">
+    <!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd">
     <fontconfig>
 
     ${optionalString (!cfg.allowBitmaps) ''
@@ -181,7 +157,7 @@ let
   # priority 53
   rejectType1 = pkgs.writeText "fc-53-nixos-reject-type1.conf" ''
     <?xml version="1.0"?>
-    <!DOCTYPE fontconfig SYSTEM "fonts.dtd">
+    <!DOCTYPE fontconfig SYSTEM "urn:fontconfig:fonts.dtd">
     <fontconfig>
 
     <!-- Reject Type 1 fonts -->
@@ -200,63 +176,46 @@ let
   confPkg = pkgs.runCommand "fontconfig-conf" {
     preferLocalBuild = true;
   } ''
-    support_folder=$out/etc/fonts/conf.d
-    latest_folder=$out/etc/fonts/${latestVersion}/conf.d
-
-    mkdir -p $support_folder
-    mkdir -p $latest_folder
+    dst=$out/etc/fonts/conf.d
+    mkdir -p $dst
 
     # fonts.conf
-    ln -s ${supportFontsConf} $support_folder/../fonts.conf
-    ln -s ${latestPkg.out}/etc/fonts/fonts.conf \
-          $latest_folder/../fonts.conf
+    ln -s ${pkg.out}/etc/fonts/fonts.conf \
+          $dst/../fonts.conf
+    # TODO: remove this legacy symlink once people stop using packages built before #95358 was merged
+    mkdir -p $out/etc/fonts/2.11
+    ln -s /etc/fonts/fonts.conf \
+          $out/etc/fonts/2.11/fonts.conf
 
     # fontconfig default config files
-    ln -s ${supportPkg.out}/etc/fonts/conf.d/*.conf \
-          $support_folder/
-    ln -s ${latestPkg.out}/etc/fonts/conf.d/*.conf \
-          $latest_folder/
-
-    # update latest 51-local.conf path to look at the latest local.conf
-    rm    $latest_folder/51-local.conf
-
-    substitute ${latestPkg.out}/etc/fonts/conf.d/51-local.conf \
-               $latest_folder/51-local.conf \
-               --replace local.conf /etc/fonts/${latestVersion}/local.conf
+    ln -s ${pkg.out}/etc/fonts/conf.d/*.conf \
+          $dst/
 
     # 00-nixos-cache.conf
-    ln -s ${cacheConfSupport} \
-          $support_folder/00-nixos-cache.conf
-    ln -s ${cacheConfLatest}  $latest_folder/00-nixos-cache.conf
+    ln -s ${cacheConf}  $dst/00-nixos-cache.conf
 
     # 10-nixos-rendering.conf
-    ln -s ${renderConf}       $support_folder/10-nixos-rendering.conf
-    ln -s ${renderConf}       $latest_folder/10-nixos-rendering.conf
+    ln -s ${renderConf}       $dst/10-nixos-rendering.conf
 
     # 50-user.conf
     ${optionalString (!cfg.includeUserConf) ''
-    rm $support_folder/50-user.conf
-    rm $latest_folder/50-user.conf
+    rm $dst/50-user.conf
     ''}
 
     # local.conf (indirect priority 51)
     ${optionalString (cfg.localConf != "") ''
-    ln -s ${localConf}        $support_folder/../local.conf
-    ln -s ${localConf}        $latest_folder/../local.conf
+    ln -s ${localConf}        $dst/../local.conf
     ''}
 
     # 52-nixos-default-fonts.conf
-    ln -s ${defaultFontsConf} $support_folder/52-nixos-default-fonts.conf
-    ln -s ${defaultFontsConf} $latest_folder/52-nixos-default-fonts.conf
+    ln -s ${defaultFontsConf} $dst/52-nixos-default-fonts.conf
 
     # 53-no-bitmaps.conf
-    ln -s ${rejectBitmaps} $support_folder/53-no-bitmaps.conf
-    ln -s ${rejectBitmaps} $latest_folder/53-no-bitmaps.conf
+    ln -s ${rejectBitmaps} $dst/53-no-bitmaps.conf
 
     ${optionalString (!cfg.allowType1) ''
     # 53-nixos-reject-type1.conf
-    ln -s ${rejectType1} $support_folder/53-nixos-reject-type1.conf
-    ln -s ${rejectType1} $latest_folder/53-nixos-reject-type1.conf
+    ln -s ${rejectType1} $dst/53-nixos-reject-type1.conf
     ''}
   '';
 
@@ -490,7 +449,7 @@ in
       environment.systemPackages    = [ pkgs.fontconfig ];
       environment.etc.fonts.source  = "${fontconfigEtc}/etc/fonts/";
     })
-    (mkIf (cfg.enable && !cfg.penultimate.enable) {
+    (mkIf cfg.enable {
       fonts.fontconfig.confPackages = [ confPkg ];
     })
   ];
diff --git a/nixos/modules/config/krb5/default.nix b/nixos/modules/config/krb5/default.nix
index ff16ffcf9c65b..c2302451d702f 100644
--- a/nixos/modules/config/krb5/default.nix
+++ b/nixos/modules/config/krb5/default.nix
@@ -41,31 +41,30 @@ let
         value)
     else value;
 
-  mkIndent = depth: concatStrings (builtins.genList (_:  " ") (2 * depth));
+  indent = "  ";
 
-  mkRelation = name: value: "${name} = ${mkVal { inherit value; }}";
+  mkRelation = name: value:
+    if (isList value) then
+      concatMapStringsSep "\n" (mkRelation name) value
+    else "${name} = ${mkVal value}";
 
-  mkVal = { value, depth ? 0 }:
+  mkVal = value:
     if (value == true) then "true"
     else if (value == false) then "false"
     else if (isInt value) then (toString value)
-    else if (isList value) then
-      concatMapStringsSep " " mkVal { inherit value depth; }
     else if (isAttrs value) then
-      (concatStringsSep "\n${mkIndent (depth + 1)}"
-        ([ "{" ] ++ (mapAttrsToList
-          (attrName: attrValue: let
-            mappedAttrValue = mkVal {
-              value = attrValue;
-              depth = depth + 1;
-            };
-          in "${attrName} = ${mappedAttrValue}")
-        value))) + "\n${mkIndent depth}}"
+      let configLines = concatLists
+        (map (splitString "\n")
+          (mapAttrsToList mkRelation value));
+      in
+      (concatStringsSep "\n${indent}"
+        ([ "{" ] ++ configLines))
+      + "\n}"
     else value;
 
   mkMappedAttrsOrString = value: concatMapStringsSep "\n"
     (line: if builtins.stringLength line > 0
-      then "${mkIndent 1}${line}"
+      then "${indent}${line}"
       else line)
     (splitString "\n"
       (if isAttrs value then
@@ -114,7 +113,10 @@ in {
           {
             "ATHENA.MIT.EDU" = {
               admin_server = "athena.mit.edu";
-              kdc = "athena.mit.edu";
+              kdc = [
+                "athena01.mit.edu"
+                "athena02.mit.edu"
+              ];
             };
           };
         '';
diff --git a/nixos/modules/config/no-x-libs.nix b/nixos/modules/config/no-x-libs.nix
index 873b8073fed9c..941ab78f86321 100644
--- a/nixos/modules/config/no-x-libs.nix
+++ b/nixos/modules/config/no-x-libs.nix
@@ -27,6 +27,7 @@ with lib;
     fonts.fontconfig.enable = false;
 
     nixpkgs.overlays = singleton (const (super: {
+      cairo = super.cairo.override { x11Support = false; };
       dbus = super.dbus.override { x11Support = false; };
       networkmanager-fortisslvpn = super.networkmanager-fortisslvpn.override { withGnome = false; };
       networkmanager-l2tp = super.networkmanager-l2tp.override { withGnome = false; };
@@ -35,6 +36,7 @@ with lib;
       networkmanager-vpnc = super.networkmanager-vpnc.override { withGnome = false; };
       networkmanager-iodine = super.networkmanager-iodine.override { withGnome = false; };
       gobject-introspection = super.gobject-introspection.override { x11Support = false; };
+      qemu = super.qemu.override { gtkSupport = false; spiceSupport = false; sdlSupport = false; };
     }));
   };
 }
diff --git a/nixos/modules/config/system-path.nix b/nixos/modules/config/system-path.nix
index ae9710e3518b6..67305e8499cb5 100644
--- a/nixos/modules/config/system-path.nix
+++ b/nixos/modules/config/system-path.nix
@@ -33,17 +33,20 @@ let
       pkgs.ncurses
       pkgs.netcat
       config.programs.ssh.package
-      pkgs.perl
       pkgs.procps
-      pkgs.rsync
-      pkgs.strace
       pkgs.su
       pkgs.time
       pkgs.utillinux
-      pkgs.which # 88K size
+      pkgs.which
       pkgs.zstd
     ];
 
+    defaultPackages = map (pkg: setPrio ((pkg.meta.priority or 5) + 3) pkg)
+      [ pkgs.perl
+        pkgs.rsync
+        pkgs.strace
+      ];
+
 in
 
 {
@@ -66,6 +69,21 @@ in
         '';
       };
 
+      defaultPackages = mkOption {
+        type = types.listOf types.package;
+        default = defaultPackages;
+        example = literalExample "[]";
+        description = ''
+          Set of packages users expect from a minimal linux istall.
+          Like systemPackages, they appear in
+          /run/current-system/sw.  These packages are
+          automatically available to all users, and are
+          automatically updated every time you rebuild the system
+          configuration.
+          If you want a more minimal system, set it to an empty list.
+        '';
+      };
+
       pathsToLink = mkOption {
         type = types.listOf types.str;
         # Note: We need `/lib' to be among `pathsToLink' for NSS modules
@@ -105,7 +123,7 @@ in
 
   config = {
 
-    environment.systemPackages = requiredPackages;
+    environment.systemPackages = requiredPackages ++ config.environment.defaultPackages;
 
     environment.pathsToLink =
       [ "/bin"
diff --git a/nixos/modules/config/update-users-groups.pl b/nixos/modules/config/update-users-groups.pl
index 15e448b787aaf..e1c7a46e43048 100644
--- a/nixos/modules/config/update-users-groups.pl
+++ b/nixos/modules/config/update-users-groups.pl
@@ -281,3 +281,58 @@ foreach my $u (values %usersOut) {
 }
 
 updateFile("/etc/shadow", \@shadowNew, 0600);
+
+# Rewrite /etc/subuid & /etc/subgid to include default container mappings
+
+my $subUidMapFile = "/var/lib/nixos/auto-subuid-map";
+my $subUidMap = -e $subUidMapFile ? decode_json(read_file($subUidMapFile)) : {};
+
+my (%subUidsUsed, %subUidsPrevUsed);
+
+$subUidsPrevUsed{$_} = 1 foreach values %{$subUidMap};
+
+sub allocSubUid {
+    my ($name, @rest) = @_;
+
+    # TODO: No upper bounds?
+    my ($min, $max, $up) = (100000, 100000 * 100, 1);
+    my $prevId = $subUidMap->{$name};
+    if (defined $prevId && !defined $subUidsUsed{$prevId}) {
+        $subUidsUsed{$prevId} = 1;
+        return $prevId;
+    }
+
+    my $id = allocId(\%subUidsUsed, \%subUidsPrevUsed, $min, $max, $up, sub { my ($uid) = @_; getpwuid($uid) });
+    my $offset = $id - 100000;
+    my $count = $offset * 65536;
+    my $subordinate = 100000 + $count;
+    return $subordinate;
+}
+
+my @subGids;
+my @subUids;
+foreach my $u (values %usersOut) {
+    my $name = $u->{name};
+
+    foreach my $range (@{$u->{subUidRanges}}) {
+        my $value = join(":", ($name, $range->{startUid}, $range->{count}));
+        push @subUids, $value;
+    }
+
+    foreach my $range (@{$u->{subGidRanges}}) {
+        my $value = join(":", ($name, $range->{startGid}, $range->{count}));
+        push @subGids, $value;
+    }
+
+    if($u->{isNormalUser}) {
+        my $subordinate = allocSubUid($name);
+        $subUidMap->{$name} = $subordinate;
+        my $value = join(":", ($name, $subordinate, 65536));
+        push @subUids, $value;
+        push @subGids, $value;
+    }
+}
+
+updateFile("/etc/subuid", join("\n", @subUids) . "\n");
+updateFile("/etc/subgid", join("\n", @subGids) . "\n");
+updateFile($subUidMapFile, encode_json($subUidMap) . "\n");
diff --git a/nixos/modules/config/users-groups.nix b/nixos/modules/config/users-groups.nix
index 7fbbfcec75107..0ab303d0ae47b 100644
--- a/nixos/modules/config/users-groups.nix
+++ b/nixos/modules/config/users-groups.nix
@@ -6,6 +6,16 @@ let
   ids = config.ids;
   cfg = config.users;
 
+  # Check whether a password hash will allow login.
+  allowsLogin = hash:
+    hash == "" # login without password
+    || !(lib.elem hash
+      [ null   # password login disabled
+        "!"    # password login disabled
+        "!!"   # a variant of "!"
+        "*"    # password unset
+      ]);
+
   passwordDescription = ''
     The options <option>hashedPassword</option>,
     <option>password</option> and <option>passwordFile</option>
@@ -25,8 +35,19 @@ let
   '';
 
   hashedPasswordDescription = ''
-    To generate hashed password install <literal>mkpasswd</literal>
+    To generate a hashed password install the <literal>mkpasswd</literal>
     package and run <literal>mkpasswd -m sha-512</literal>.
+
+    If set to an empty string (<literal>""</literal>), this user will
+    be able to log in without being asked for a password (but not via remote
+    services such as SSH, or indirectly via <command>su</command> or
+    <command>sudo</command>). This should only be used for e.g. bootable
+    live systems. Note: this is different from setting an empty password,
+    which ca be achieved using <option>users.users.&lt;name?&gt;.password</option>.
+
+    If set to <literal>null</literal> (default) this user will not
+    be able to log in using a password (i.e. via <command>login</command>
+    command).
   '';
 
   userOpts = { name, config, ... }: {
@@ -354,18 +375,6 @@ let
     };
   };
 
-  mkSubuidEntry = user: concatStrings (
-    map (range: "${user.name}:${toString range.startUid}:${toString range.count}\n")
-      user.subUidRanges);
-
-  subuidFile = concatStrings (map mkSubuidEntry (attrValues cfg.users));
-
-  mkSubgidEntry = user: concatStrings (
-    map (range: "${user.name}:${toString range.startGid}:${toString range.count}\n")
-        user.subGidRanges);
-
-  subgidFile = concatStrings (map mkSubgidEntry (attrValues cfg.users));
-
   idsAreUnique = set: idAttr: !(fold (name: args@{ dup, acc }:
     let
       id = builtins.toString (builtins.getAttr idAttr (builtins.getAttr name set));
@@ -385,6 +394,7 @@ let
       { inherit (u)
           name uid group description home createHome isSystemUser
           password passwordFile hashedPassword
+          isNormalUser subUidRanges subGidRanges
           initialPassword initialHashedPassword;
         shell = utils.toShellPath u.shell;
       }) cfg.users;
@@ -406,6 +416,12 @@ in {
   imports = [
     (mkAliasOptionModule [ "users" "extraUsers" ] [ "users" "users" ])
     (mkAliasOptionModule [ "users" "extraGroups" ] [ "users" "groups" ])
+    (mkChangedOptionModule
+      [ "security" "initialRootPassword" ]
+      [ "users" "users" "root" "initialHashedPassword" ]
+      (cfg: if cfg.security.initialRootPassword == "!"
+            then null
+            else cfg.security.initialRootPassword))
   ];
 
   ###### interface
@@ -447,7 +463,7 @@ in {
 
     users.users = mkOption {
       default = {};
-      type = with types; loaOf (submodule userOpts);
+      type = with types; attrsOf (submodule userOpts);
       example = {
         alice = {
           uid = 1234;
@@ -471,20 +487,12 @@ in {
         { students.gid = 1001;
           hackers = { };
         };
-      type = with types; loaOf (submodule groupOpts);
+      type = with types; attrsOf (submodule groupOpts);
       description = ''
         Additional groups to be created automatically by the system.
       '';
     };
 
-    # FIXME: obsolete - will remove.
-    security.initialRootPassword = mkOption {
-      type = types.str;
-      default = "!";
-      example = "";
-      visible = false;
-    };
-
   };
 
 
@@ -499,7 +507,6 @@ in {
         home = "/root";
         shell = mkDefault cfg.defaultUserShell;
         group = "root";
-        initialHashedPassword = mkDefault config.security.initialRootPassword;
       };
       nobody = {
         uid = ids.uids.nobody;
@@ -549,16 +556,7 @@ in {
     # Install all the user shells
     environment.systemPackages = systemShells;
 
-    environment.etc = {
-      subuid = {
-        text = subuidFile;
-        mode = "0644";
-      };
-      subgid = {
-        text = subgidFile;
-        mode = "0644";
-      };
-    } // (mapAttrs' (name: { packages, ... }: {
+    environment.etc = (mapAttrs' (name: { packages, ... }: {
       name = "profiles/per-user/${name}";
       value.source = pkgs.buildEnv {
         name = "user-environment";
@@ -583,22 +581,34 @@ in {
         # password or an SSH authorized key. Privileged accounts are
         # root and users in the wheel group.
         assertion = !cfg.mutableUsers ->
-          any id (mapAttrsToList (name: cfg:
+          any id ((mapAttrsToList (name: cfg:
             (name == "root"
              || cfg.group == "wheel"
              || elem "wheel" cfg.extraGroups)
             &&
-            ((cfg.hashedPassword != null && cfg.hashedPassword != "!")
+            (allowsLogin cfg.hashedPassword
              || cfg.password != null
              || cfg.passwordFile != null
              || cfg.openssh.authorizedKeys.keys != []
              || cfg.openssh.authorizedKeys.keyFiles != [])
-          ) cfg.users);
+          ) cfg.users) ++ [
+            config.security.googleOsLogin.enable
+          ]);
         message = ''
           Neither the root account nor any wheel user has a password or SSH authorized key.
           You must set one to prevent being locked out of your system.'';
       }
-    ];
+    ] ++ flip mapAttrsToList cfg.users (name: user:
+      {
+        assertion = (user.hashedPassword != null)
+                    -> (builtins.match ".*:.*" user.hashedPassword == null);
+        message = ''
+          The password hash of user "${name}" contains a ":" character.
+          This is invalid and would break the login system because the fields
+          of /etc/shadow (file where hashes are stored) are colon-separated.
+          Please check the value of option `users.users."${name}".hashedPassword`.'';
+      }
+    );
 
     warnings =
       builtins.filter (x: x != null) (
@@ -621,14 +631,13 @@ in {
           content = "${base64}${sep}${base64}";
           mcf = "^${sep}${scheme}${sep}${content}$";
         in
-        if (user.hashedPassword != null
+        if (allowsLogin user.hashedPassword
+            && user.hashedPassword != ""  # login without password
             && builtins.match mcf user.hashedPassword == null)
-        then
-        ''
+        then ''
           The password hash of user "${name}" may be invalid. You must set a
-          valid hash or the user will be locked out of his account. Please
-          check the value of option `users.users."${name}".hashedPassword`.
-        ''
+          valid hash or the user will be locked out of their account. Please
+          check the value of option `users.users."${name}".hashedPassword`.''
         else null
       ));
 
diff --git a/nixos/modules/hardware/bladeRF.nix b/nixos/modules/hardware/bladeRF.nix
index 9254434771431..35b74b8382e3a 100644
--- a/nixos/modules/hardware/bladeRF.nix
+++ b/nixos/modules/hardware/bladeRF.nix
@@ -25,4 +25,4 @@ in
     services.udev.packages = [ pkgs.libbladeRF ];
     users.groups.bladerf = {};
   };
-}
\ No newline at end of file
+}
diff --git a/nixos/modules/hardware/ckb-next.nix b/nixos/modules/hardware/ckb-next.nix
index fe0ca9f26d54d..6932be1c54cad 100644
--- a/nixos/modules/hardware/ckb-next.nix
+++ b/nixos/modules/hardware/ckb-next.nix
@@ -43,7 +43,6 @@ in
         serviceConfig = {
           ExecStart = "${cfg.package}/bin/ckb-next-daemon ${optionalString (cfg.gid != null) "--gid=${builtins.toString cfg.gid}"}";
           Restart = "on-failure";
-          StandardOutput = "syslog";
         };
       };
     };
diff --git a/nixos/modules/hardware/device-tree.nix b/nixos/modules/hardware/device-tree.nix
index cf553497c89b3..e0ab37bca63a5 100644
--- a/nixos/modules/hardware/device-tree.nix
+++ b/nixos/modules/hardware/device-tree.nix
@@ -4,7 +4,114 @@ with lib;
 
 let
   cfg = config.hardware.deviceTree;
-in {
+
+  overlayType = types.submodule {
+    options = {
+      name = mkOption {
+        type = types.str;
+        description = ''
+          Name of this overlay
+        '';
+      };
+
+      dtsFile = mkOption {
+        type = types.nullOr types.path;
+        description = ''
+          Path to .dts overlay file, overlay is applied to
+          each .dtb file matching "compatible" of the overlay.
+        '';
+        default = null;
+        example = literalExample "./dts/overlays.dts";
+      };
+
+      dtsText = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = ''
+          Literal DTS contents, overlay is applied to
+          each .dtb file matching "compatible" of the overlay.
+        '';
+        example = literalExample ''
+          /dts-v1/;
+          /plugin/;
+          / {
+                  compatible = "raspberrypi";
+                  fragment@0 {
+                          target-path = "/soc";
+                          __overlay__ {
+                                  pps {
+                                          compatible = "pps-gpio";
+                                          status = "okay";
+                                  };
+                          };
+                  };
+          };
+        '';
+      };
+
+      dtboFile = mkOption {
+        type = types.nullOr types.path;
+        default = null;
+        description = ''
+          Path to .dtbo compiled overlay file.
+        '';
+      };
+    };
+  };
+
+  # this requires kernel package
+  dtbsWithSymbols = pkgs.stdenv.mkDerivation {
+    name = "dtbs-with-symbols";
+    inherit (cfg.kernelPackage) src nativeBuildInputs depsBuildBuild;
+    patches = map (patch: patch.patch) cfg.kernelPackage.kernelPatches;
+    buildPhase = ''
+      patchShebangs scripts/*
+      substituteInPlace scripts/Makefile.lib \
+        --replace 'DTC_FLAGS += $(DTC_FLAGS_$(basetarget))' 'DTC_FLAGS += $(DTC_FLAGS_$(basetarget)) -@'
+      make ${pkgs.stdenv.hostPlatform.platform.kernelBaseConfig} ARCH="${pkgs.stdenv.hostPlatform.platform.kernelArch}"
+      make dtbs ARCH="${pkgs.stdenv.hostPlatform.platform.kernelArch}"
+    '';
+    installPhase = ''
+      make dtbs_install INSTALL_DTBS_PATH=$out/dtbs  ARCH="${pkgs.stdenv.hostPlatform.platform.kernelArch}"
+    '';
+  };
+
+  filterDTBs = src: if isNull cfg.filter
+    then "${src}/dtbs"
+    else
+      pkgs.runCommand "dtbs-filtered" {} ''
+        mkdir -p $out
+        cd ${src}/dtbs
+        find . -type f -name '${cfg.filter}' -print0 \
+          | xargs -0 cp -v --no-preserve=mode --target-directory $out --parents
+      '';
+
+  # Compile single Device Tree overlay source
+  # file (.dts) into its compiled variant (.dtbo)
+  compileDTS = name: f: pkgs.callPackage({ dtc }: pkgs.stdenv.mkDerivation {
+    name = "${name}-dtbo";
+
+    nativeBuildInputs = [ dtc ];
+
+    buildCommand = ''
+      dtc -I dts ${f} -O dtb -@ -o $out
+    '';
+  }) {};
+
+  # Fill in `dtboFile` for each overlay if not set already.
+  # Existence of one of these is guarded by assertion below
+  withDTBOs = xs: flip map xs (o: o // { dtboFile =
+    if isNull o.dtboFile then
+      if !isNull o.dtsFile then compileDTS o.name o.dtsFile
+      else compileDTS o.name (pkgs.writeText "dts" o.dtsText)
+    else o.dtboFile; } );
+
+in
+{
+  imports = [
+    (mkRemovedOptionModule [ "hardware" "deviceTree" "base" ] "Use hardware.deviceTree.kernelPackage instead")
+  ];
+
   options = {
       hardware.deviceTree = {
         enable = mkOption {
@@ -16,25 +123,54 @@ in {
           '';
         };
 
-        base = mkOption {
-          default = "${config.boot.kernelPackages.kernel}/dtbs";
-          defaultText = "\${config.boot.kernelPackages.kernel}/dtbs";
-          example = literalExample "pkgs.device-tree_rpi";
+        kernelPackage = mkOption {
+          default = config.boot.kernelPackages.kernel;
+          defaultText = "config.boot.kernelPackages.kernel";
+          example = literalExample "pkgs.linux_latest";
           type = types.path;
           description = ''
-            The package containing the base device-tree (.dtb) to boot. Contains
+            Kernel package containing the base device-tree (.dtb) to boot. Uses
             device trees bundled with the Linux kernel by default.
           '';
         };
 
+        name = mkOption {
+          default = null;
+          example = "some-dtb.dtb";
+          type = types.nullOr types.str;
+          description = ''
+            The name of an explicit dtb to be loaded, relative to the dtb base.
+            Useful in extlinux scenarios if the bootloader doesn't pick the
+            right .dtb file from FDTDIR.
+          '';
+        };
+
+        filter = mkOption {
+          type = types.nullOr types.str;
+          default = null;
+          example = "*rpi*.dtb";
+          description = ''
+            Only include .dtb files matching glob expression.
+          '';
+        };
+
         overlays = mkOption {
           default = [];
-          example = literalExample
-            "[\"\${pkgs.device-tree_rpi.overlays}/w1-gpio.dtbo\"]";
-          type = types.listOf types.path;
+          example = literalExample ''
+            [
+              { name = "pps"; dtsFile = ./dts/pps.dts; }
+              { name = "spi";
+                dtsText = "...";
+              }
+              { name = "precompiled"; dtboFile = ./dtbos/example.dtbo; }
+            ]
+          '';
+          type = types.listOf (types.coercedTo types.path (path: {
+            name = baseNameOf path;
+            dtboFile = path;
+          }) overlayType);
           description = ''
-            A path containing device tree overlays (.dtbo) to be applied to all
-            base device-trees.
+            List of overlays to apply to base device-tree (.dtb) files.
           '';
         };
 
@@ -43,14 +179,27 @@ in {
           type = types.nullOr types.path;
           internal = true;
           description = ''
-            A path containing the result of applying `overlays` to `base`.
+            A path containing the result of applying `overlays` to `kernelPackage`.
           '';
         };
       };
   };
 
   config = mkIf (cfg.enable) {
+
+    assertions = let
+      invalidOverlay = o: isNull o.dtsFile && isNull o.dtsText && isNull o.dtboFile;
+    in lib.singleton {
+      assertion = lib.all (o: !invalidOverlay o) cfg.overlays;
+      message = ''
+        deviceTree overlay needs one of dtsFile, dtsText or dtboFile set.
+        Offending overlay(s):
+        ${toString (map (o: o.name) (builtins.filter invalidOverlay cfg.overlays))}
+      '';
+    };
+
     hardware.deviceTree.package = if (cfg.overlays != [])
-      then pkgs.deviceTree.applyOverlays cfg.base cfg.overlays else cfg.base;
+      then pkgs.deviceTree.applyOverlays (filterDTBs dtbsWithSymbols) (withDTBOs cfg.overlays)
+      else (filterDTBs cfg.kernelPackage);
   };
 }
diff --git a/nixos/modules/hardware/logitech.nix b/nixos/modules/hardware/logitech.nix
index d6f43bdddcc8c..3ebe6aacf5d68 100644
--- a/nixos/modules/hardware/logitech.nix
+++ b/nixos/modules/hardware/logitech.nix
@@ -5,24 +5,92 @@ with lib;
 let
   cfg = config.hardware.logitech;
 
-in {
+  vendor = "046d";
+
+  daemon = "g15daemon";
+
+in
+{
+  imports = [
+    (mkRenamedOptionModule [ "hardware" "logitech" "enable" ] [ "hardware" "logitech" "wireless" "enable" ])
+    (mkRenamedOptionModule [ "hardware" "logitech" "enableGraphical" ] [ "hardware" "logitech" "wireless" "enableGraphical" ])
+  ];
+
   options.hardware.logitech = {
-    enable = mkEnableOption "Logitech Devices";
 
-    enableGraphical = mkOption {
-      type = types.bool;
-      default = false;
-      description = "Enable graphical support applications.";
+    lcd = {
+      enable = mkEnableOption "Logitech LCD Devices";
+
+      startWhenNeeded = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          Only run the service when an actual supported device is plugged.
+        '';
+      };
+
+      devices = mkOption {
+        type = types.listOf types.str;
+        default = [ "0a07" "c222" "c225" "c227" "c251" ];
+        description = ''
+          List of USB device ids supported by g15daemon.
+          </para>
+          <para>
+          You most likely do not need to change this.
+        '';
+      };
+    };
+
+    wireless = {
+      enable = mkEnableOption "Logitech Wireless Devices";
+
+      enableGraphical = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Enable graphical support applications.";
+      };
     };
   };
 
-  config = lib.mkIf cfg.enable {
-    environment.systemPackages = [
-      pkgs.ltunify
-    ] ++ lib.optional cfg.enableGraphical pkgs.solaar;
+  config = lib.mkIf (cfg.wireless.enable || cfg.lcd.enable) {
+    environment.systemPackages = []
+      ++ lib.optional cfg.wireless.enable pkgs.ltunify
+      ++ lib.optional cfg.wireless.enableGraphical pkgs.solaar;
+
+    services.udev = {
+      # ltunifi and solaar both provide udev rules but the most up-to-date have been split
+      # out into a dedicated derivation
 
-    # ltunifi and solaar both provide udev rules but the most up-to-date have been split
-    # out into a dedicated derivation
-    services.udev.packages = with pkgs; [ logitech-udev-rules ];
+      packages = []
+      ++ lib.optional cfg.wireless.enable pkgs.logitech-udev-rules
+      ++ lib.optional cfg.lcd.enable pkgs.g15daemon;
+
+      extraRules = ''
+        # nixos: hardware.logitech.lcd
+      '' + lib.concatMapStringsSep "\n" (
+        dev:
+          ''ACTION=="add", SUBSYSTEMS=="usb", ATTRS{idVendor}=="${vendor}", ATTRS{idProduct}=="${dev}", TAG+="systemd", ENV{SYSTEMD_WANTS}+="${daemon}.service"''
+      ) cfg.lcd.devices;
+    };
+
+    systemd.services."${daemon}" = lib.mkIf cfg.lcd.enable {
+      description = "Logitech LCD Support Daemon";
+      documentation = [ "man:g15daemon(1)" ];
+      wantedBy = lib.mkIf (! cfg.lcd.startWhenNeeded) "multi-user.target";
+
+      serviceConfig = {
+        Type = "forking";
+        ExecStart = "${pkgs.g15daemon}/bin/g15daemon";
+        # we patch it to write to /run/g15daemon/g15daemon.pid instead of
+        # /run/g15daemon.pid so systemd will do the cleanup for us.
+        PIDFile = "/run/${daemon}/g15daemon.pid";
+        PrivateTmp = true;
+        PrivateNetwork = true;
+        ProtectHome = "tmpfs";
+        ProtectSystem = "full"; # strict doesn't work
+        RuntimeDirectory = daemon;
+        Restart = "on-failure";
+      };
+    };
   };
 }
diff --git a/nixos/modules/hardware/onlykey.nix b/nixos/modules/hardware/onlykey.nix
index b6820fe01911f..07358c8a87820 100644
--- a/nixos/modules/hardware/onlykey.nix
+++ b/nixos/modules/hardware/onlykey.nix
@@ -26,7 +26,7 @@ with lib;
   ####### implementation
 
   config = mkIf config.hardware.onlykey.enable {
-    services.udev.extraRules = builtin.readFile ./onlykey.udev;
+    services.udev.extraRules = builtins.readFile ./onlykey.udev;
   };
 
 
diff --git a/nixos/modules/hardware/tuxedo-keyboard.nix b/nixos/modules/hardware/tuxedo-keyboard.nix
index 898eed2449355..97af7c61f3c9a 100644
--- a/nixos/modules/hardware/tuxedo-keyboard.nix
+++ b/nixos/modules/hardware/tuxedo-keyboard.nix
@@ -2,7 +2,7 @@
 
 with lib;
 
-let 
+let
   cfg = config.hardware.tuxedo-keyboard;
   tuxedo-keyboard = config.boot.kernelPackages.tuxedo-keyboard;
 in
@@ -27,7 +27,7 @@ in
       '';
     };
 
-    config = mkIf cfg.enable 
+    config = mkIf cfg.enable
     {
       boot.kernelModules = ["tuxedo_keyboard"];
       boot.extraModulePackages = [ tuxedo-keyboard ];
diff --git a/nixos/modules/hardware/video/hidpi.nix b/nixos/modules/hardware/video/hidpi.nix
new file mode 100644
index 0000000000000..ac72b652504ec
--- /dev/null
+++ b/nixos/modules/hardware/video/hidpi.nix
@@ -0,0 +1,16 @@
+{ lib, pkgs, config, ...}:
+with lib;
+
+{
+  options.hardware.video.hidpi.enable = mkEnableOption "Font/DPI configuration optimized for HiDPI displays";
+
+  config = mkIf config.hardware.video.hidpi.enable {
+    console.font = lib.mkDefault "${pkgs.terminus_font}/share/consolefonts/ter-v32n.psf.gz";
+
+    # Needed when typing in passwords for full disk encryption
+    console.earlySetup = mkDefault true;
+    boot.loader.systemd-boot.consoleMode = mkDefault "1";
+
+    # TODO Find reasonable defaults X11 & wayland
+  };
+}
diff --git a/nixos/modules/hardware/video/uvcvideo/default.nix b/nixos/modules/hardware/video/uvcvideo/default.nix
index 7e3e94fdf2bd6..cf6aa052abb05 100644
--- a/nixos/modules/hardware/video/uvcvideo/default.nix
+++ b/nixos/modules/hardware/video/uvcvideo/default.nix
@@ -26,7 +26,7 @@ in
           Whether to enable <command>uvcvideo</command> dynamic controls.
 
           Note that enabling this brings the <command>uvcdynctrl</command> tool
-          into your environement and register all dynamic controls from
+          into your environment and register all dynamic controls from
           specified <command>packages</command> to the <command>uvcvideo</command> driver.
         '';
       };
diff --git a/nixos/modules/hardware/xpadneo.nix b/nixos/modules/hardware/xpadneo.nix
new file mode 100644
index 0000000000000..d504697e61fd9
--- /dev/null
+++ b/nixos/modules/hardware/xpadneo.nix
@@ -0,0 +1,29 @@
+{ config, lib, ... }:
+
+with lib;
+let
+  cfg = config.hardware.xpadneo;
+in
+{
+  options.hardware.xpadneo = {
+    enable = mkEnableOption "the xpadneo driver for Xbox One wireless controllers";
+  };
+
+  config = mkIf cfg.enable {
+    boot = {
+      # Must disable Enhanced Retransmission Mode to support bluetooth pairing
+      # https://wiki.archlinux.org/index.php/Gamepad#Connect_Xbox_Wireless_Controller_with_Bluetooth
+      extraModprobeConfig =
+        mkIf
+          config.hardware.bluetooth.enable
+          "options bluetooth disable_ertm=1";
+
+      extraModulePackages = with config.boot.kernelPackages; [ xpadneo ];
+      kernelModules = [ "hid_xpadneo" ];
+    };
+  };
+
+  meta = {
+    maintainers = with maintainers; [ metadark ];
+  };
+}
diff --git a/nixos/modules/i18n/input-method/ibus.nix b/nixos/modules/i18n/input-method/ibus.nix
index b4746b21b653f..cf24ecf586316 100644
--- a/nixos/modules/i18n/input-method/ibus.nix
+++ b/nixos/modules/i18n/input-method/ibus.nix
@@ -64,7 +64,7 @@ in
     # Without dconf enabled it is impossible to use IBus
     programs.dconf.enable = true;
 
-    programs.dconf.profiles.ibus = "${ibusPackage}/etc/dconf/profile/ibus";
+    programs.dconf.packages = [ ibusPackage ];
 
     services.dbus.packages = [
       ibusAutostart
diff --git a/nixos/modules/i18n/input-method/uim.nix b/nixos/modules/i18n/input-method/uim.nix
index 7ad68bf851feb..459294657e0a6 100644
--- a/nixos/modules/i18n/input-method/uim.nix
+++ b/nixos/modules/i18n/input-method/uim.nix
@@ -2,7 +2,7 @@
 
 with lib;
 
-let 
+let
   cfg = config.i18n.inputMethod.uim;
 in
 {
diff --git a/nixos/modules/installer/cd-dvd/installation-cd-graphical-gnome.nix b/nixos/modules/installer/cd-dvd/installation-cd-graphical-gnome.nix
index 3707c4b7ec62b..8c98691116dc9 100644
--- a/nixos/modules/installer/cd-dvd/installation-cd-graphical-gnome.nix
+++ b/nixos/modules/installer/cd-dvd/installation-cd-graphical-gnome.nix
@@ -11,15 +11,17 @@ with lib;
 
   services.xserver.desktopManager.gnome3.enable = true;
 
-  services.xserver.displayManager.gdm = {
-    enable = true;
-    # autoSuspend makes the machine automatically suspend after inactivity.
-    # It's possible someone could/try to ssh'd into the machine and obviously
-    # have issues because it's inactive.
-    # See:
-    # * https://github.com/NixOS/nixpkgs/pull/63790
-    # * https://gitlab.gnome.org/GNOME/gnome-control-center/issues/22
-    autoSuspend = false;
+  services.xserver.displayManager = {
+    gdm = {
+      enable = true;
+      # autoSuspend makes the machine automatically suspend after inactivity.
+      # It's possible someone could/try to ssh'd into the machine and obviously
+      # have issues because it's inactive.
+      # See:
+      # * https://github.com/NixOS/nixpkgs/pull/63790
+      # * https://gitlab.gnome.org/GNOME/gnome-control-center/issues/22
+      autoSuspend = false;
+    };
     autoLogin = {
       enable = true;
       user = "nixos";
diff --git a/nixos/modules/installer/cd-dvd/installation-cd-graphical-plasma5.nix b/nixos/modules/installer/cd-dvd/installation-cd-graphical-plasma5.nix
index e76e06654aca0..098c2b2870b04 100644
--- a/nixos/modules/installer/cd-dvd/installation-cd-graphical-plasma5.nix
+++ b/nixos/modules/installer/cd-dvd/installation-cd-graphical-plasma5.nix
@@ -16,8 +16,8 @@ with lib;
     };
 
     # Automatically login as nixos.
-    displayManager.sddm = {
-      enable = true;
+    displayManager = {
+      sddm.enable = true;
       autoLogin = {
         enable = true;
         user = "nixos";
diff --git a/nixos/modules/installer/cd-dvd/iso-image.nix b/nixos/modules/installer/cd-dvd/iso-image.nix
index 1cd2252ecf24f..405fbfa10dbfd 100644
--- a/nixos/modules/installer/cd-dvd/iso-image.nix
+++ b/nixos/modules/installer/cd-dvd/iso-image.nix
@@ -417,6 +417,14 @@ in
       '';
     };
 
+    isoImage.squashfsCompression = mkOption {
+      default = "xz -Xdict-size 100%";
+      description = ''
+        Compression settings to use for the squashfs nix store.
+      '';
+      example = "zstd -Xcompression-level 6";
+    };
+
     isoImage.edition = mkOption {
       default = "";
       description = ''
@@ -614,6 +622,7 @@ in
     # Create the squashfs image that contains the Nix store.
     system.build.squashfsStore = pkgs.callPackage ../../../lib/make-squashfs.nix {
       storeContents = config.isoImage.storeContents;
+      comp = config.isoImage.squashfsCompression;
     };
 
     # Individual files to be included on the CD, outside of the Nix
diff --git a/nixos/modules/installer/cd-dvd/sd-image-aarch64.nix b/nixos/modules/installer/cd-dvd/sd-image-aarch64.nix
index 2d34406a0320e..bef6cd2fb5a22 100644
--- a/nixos/modules/installer/cd-dvd/sd-image-aarch64.nix
+++ b/nixos/modules/installer/cd-dvd/sd-image-aarch64.nix
@@ -2,12 +2,6 @@
 # nix-build nixos -I nixos-config=nixos/modules/installer/cd-dvd/sd-image-aarch64.nix -A config.system.build.sdImage
 { config, lib, pkgs, ... }:
 
-let
-  extlinux-conf-builder =
-    import ../../system/boot/loader/generic-extlinux-compatible/extlinux-conf-builder.nix {
-      pkgs = pkgs.buildPackages;
-    };
-in
 {
   imports = [
     ../../profiles/base.nix
@@ -56,7 +50,7 @@ in
       '';
     populateRootCommands = ''
       mkdir -p ./files/boot
-      ${extlinux-conf-builder} -t 3 -c ${config.system.build.toplevel} -d ./files/boot
+      ${config.boot.loader.generic-extlinux-compatible.populateCmd} -c ${config.system.build.toplevel} -d ./files/boot
     '';
   };
 
diff --git a/nixos/modules/installer/cd-dvd/sd-image-armv7l-multiplatform.nix b/nixos/modules/installer/cd-dvd/sd-image-armv7l-multiplatform.nix
index 651d1a36dc11b..d2ba611532e0b 100644
--- a/nixos/modules/installer/cd-dvd/sd-image-armv7l-multiplatform.nix
+++ b/nixos/modules/installer/cd-dvd/sd-image-armv7l-multiplatform.nix
@@ -2,12 +2,6 @@
 # nix-build nixos -I nixos-config=nixos/modules/installer/cd-dvd/sd-image-armv7l-multiplatform.nix -A config.system.build.sdImage
 { config, lib, pkgs, ... }:
 
-let
-  extlinux-conf-builder =
-    import ../../system/boot/loader/generic-extlinux-compatible/extlinux-conf-builder.nix {
-      pkgs = pkgs.buildPackages;
-    };
-in
 {
   imports = [
     ../../profiles/base.nix
@@ -53,7 +47,7 @@ in
       '';
     populateRootCommands = ''
       mkdir -p ./files/boot
-      ${extlinux-conf-builder} -t 3 -c ${config.system.build.toplevel} -d ./files/boot
+      ${config.boot.loader.generic-extlinux-compatible.populateCmd} -c ${config.system.build.toplevel} -d ./files/boot
     '';
   };
 
diff --git a/nixos/modules/installer/cd-dvd/sd-image-raspberrypi.nix b/nixos/modules/installer/cd-dvd/sd-image-raspberrypi.nix
index ba4127eaa0e85..40a01f9617710 100644
--- a/nixos/modules/installer/cd-dvd/sd-image-raspberrypi.nix
+++ b/nixos/modules/installer/cd-dvd/sd-image-raspberrypi.nix
@@ -2,12 +2,6 @@
 # nix-build nixos -I nixos-config=nixos/modules/installer/cd-dvd/sd-image-raspberrypi.nix -A config.system.build.sdImage
 { config, lib, pkgs, ... }:
 
-let
-  extlinux-conf-builder =
-    import ../../system/boot/loader/generic-extlinux-compatible/extlinux-conf-builder.nix {
-      pkgs = pkgs.buildPackages;
-    };
-in
 {
   imports = [
     ../../profiles/base.nix
@@ -42,7 +36,7 @@ in
       '';
     populateRootCommands = ''
       mkdir -p ./files/boot
-      ${extlinux-conf-builder} -t 3 -c ${config.system.build.toplevel} -d ./files/boot
+      ${config.boot.loader.generic-extlinux-compatible.populateCmd} -c ${config.system.build.toplevel} -d ./files/boot
     '';
   };
 
diff --git a/nixos/modules/installer/cd-dvd/sd-image-raspberrypi4.nix b/nixos/modules/installer/cd-dvd/sd-image-raspberrypi4.nix
index c545a1e7e2424..87545e8420308 100644
--- a/nixos/modules/installer/cd-dvd/sd-image-raspberrypi4.nix
+++ b/nixos/modules/installer/cd-dvd/sd-image-raspberrypi4.nix
@@ -18,6 +18,7 @@
 
   sdImage = {
     firmwareSize = 128;
+    firmwarePartitionName = "NIXOS_BOOT";
     # This is a hack to avoid replicating config.txt from boot.loader.raspberryPi
     populateFirmwareCommands =
       "${config.system.build.installBootLoader} ${config.system.build.toplevel} -d ./firmware";
@@ -25,6 +26,12 @@
     populateRootCommands = "";
   };
 
+  fileSystems."/boot/firmware" = {
+    # This effectively "renames" the attrsOf entry set in sd-image.nix
+    mountPoint = "/boot";
+    neededForBoot = true;
+  };
+
   # the installation media is also the installation target,
   # so we don't want to provide the installation configuration.nix.
   installer.cloneConfig = false;
diff --git a/nixos/modules/installer/cd-dvd/sd-image.nix b/nixos/modules/installer/cd-dvd/sd-image.nix
index 98c12e30633c4..231c7bf0a6c25 100644
--- a/nixos/modules/installer/cd-dvd/sd-image.nix
+++ b/nixos/modules/installer/cd-dvd/sd-image.nix
@@ -63,6 +63,14 @@ in
       '';
     };
 
+    firmwarePartitionName = mkOption {
+      type = types.str;
+      default = "FIRMWARE";
+      description = ''
+        Name of the filesystem which holds the boot firmware.
+      '';
+    };
+
     rootPartitionUUID = mkOption {
       type = types.nullOr types.str;
       default = null;
@@ -91,7 +99,7 @@ in
     };
 
     populateRootCommands = mkOption {
-      example = literalExample "''\${extlinux-conf-builder} -t 3 -c \${config.system.build.toplevel} -d ./files/boot''";
+      example = literalExample "''\${config.boot.loader.generic-extlinux-compatible.populateCmd} -c \${config.system.build.toplevel} -d ./files/boot''";
       description = ''
         Shell commands to populate the ./files directory.
         All files in that directory are copied to the
@@ -100,6 +108,15 @@ in
       '';
     };
 
+    postBuildCommands = mkOption {
+      example = literalExample "'' dd if=\${pkgs.myBootLoader}/SPL of=$img bs=1024 seek=1 conv=notrunc ''";
+      default = "";
+      description = ''
+        Shell commands to run after the image is built.
+        Can be used for boards requiring to dd u-boot SPL before actual partitions.
+      '';
+    };
+
     compressImage = mkOption {
       type = types.bool;
       default = true;
@@ -114,7 +131,7 @@ in
   config = {
     fileSystems = {
       "/boot/firmware" = {
-        device = "/dev/disk/by-label/FIRMWARE";
+        device = "/dev/disk/by-label/${config.sdImage.firmwarePartitionName}";
         fsType = "vfat";
         # Alternatively, this could be removed from the configuration.
         # The filesystem is not needed at runtime, it could be treated
@@ -178,7 +195,7 @@ in
         # Create a FAT32 /boot/firmware partition of suitable size into firmware_part.img
         eval $(partx $img -o START,SECTORS --nr 1 --pairs)
         truncate -s $((SECTORS * 512)) firmware_part.img
-        faketime "1970-01-01 00:00:00" mkfs.vfat -i ${config.sdImage.firmwarePartitionID} -n FIRMWARE firmware_part.img
+        faketime "1970-01-01 00:00:00" mkfs.vfat -i ${config.sdImage.firmwarePartitionID} -n ${config.sdImage.firmwarePartitionName} firmware_part.img
 
         # Populate the files intended for /boot/firmware
         mkdir firmware
@@ -189,6 +206,9 @@ in
         # Verify the FAT partition before copying it.
         fsck.vfat -vn firmware_part.img
         dd conv=notrunc if=firmware_part.img of=$img seek=$START count=$SECTORS
+
+        ${config.sdImage.postBuildCommands}
+
         if test -n "$compressImage"; then
             zstd -T$NIX_BUILD_CORES --rm $img
         fi
diff --git a/nixos/modules/installer/cd-dvd/system-tarball-pc-readme.txt b/nixos/modules/installer/cd-dvd/system-tarball-pc-readme.txt
index 84252f292c54a..887bf60d0fbe4 100644
--- a/nixos/modules/installer/cd-dvd/system-tarball-pc-readme.txt
+++ b/nixos/modules/installer/cd-dvd/system-tarball-pc-readme.txt
@@ -63,7 +63,7 @@ Activate the system: look for a directory in nix/store similar to:
 Having found it, activate that nixos system *twice*:
   chroot . /nix/store/SOMETHING-nixos-SOMETHING/activate
   chroot . /nix/store/SOMETHING-nixos-SOMETHING/activate
-  
+
 This runs a 'hostname' command. Restore your old hostname with:
   hostname OLDHOSTNAME
 
diff --git a/nixos/modules/installer/tools/nix-fallback-paths.nix b/nixos/modules/installer/tools/nix-fallback-paths.nix
index 35a7b382b7cf7..a15a2dbadb8c6 100644
--- a/nixos/modules/installer/tools/nix-fallback-paths.nix
+++ b/nixos/modules/installer/tools/nix-fallback-paths.nix
@@ -1,6 +1,6 @@
 {
-  x86_64-linux = "/nix/store/j8dbv5w6jl34caywh2ygdy88knx1mdf7-nix-2.3.6";
-  i686-linux = "/nix/store/9fqvbdisahqp0238vrs7wn5anpri0a65-nix-2.3.6";
-  aarch64-linux = "/nix/store/72pwn0nm9bjqx9vpi8sgh4bl6g5wh814-nix-2.3.6";
-  x86_64-darwin = "/nix/store/g37vk77m90p5zcl5nixjlzp3vqpisfn5-nix-2.3.6";
+  x86_64-linux = "/nix/store/4vz8sh9ngx34ivi0bw5hlycxdhvy5hvz-nix-2.3.7";
+  i686-linux = "/nix/store/dzxkg9lpp60bjmzvagns42vqlz3yq5kx-nix-2.3.7";
+  aarch64-linux = "/nix/store/cfvf8nl8mwyw817by5y8zd3s8pnf5m9f-nix-2.3.7";
+  x86_64-darwin = "/nix/store/5ira7xgs92inqz1x8l0n1wci4r79hnd0-nix-2.3.7";
 }
diff --git a/nixos/modules/installer/tools/nixos-build-vms/nixos-build-vms.sh b/nixos/modules/installer/tools/nixos-build-vms/nixos-build-vms.sh
index 25106733087ef..2a6c3ab11497f 100644
--- a/nixos/modules/installer/tools/nixos-build-vms/nixos-build-vms.sh
+++ b/nixos/modules/installer/tools/nixos-build-vms/nixos-build-vms.sh
@@ -1,4 +1,4 @@
-#! @shell@ -e
+#! @runtimeShell@ -e
 
 # Shows the usage of this command to the user
 
diff --git a/nixos/modules/installer/tools/nixos-enter.sh b/nixos/modules/installer/tools/nixos-enter.sh
index 1fdd4627a902c..c72ef6e9c28b3 100644
--- a/nixos/modules/installer/tools/nixos-enter.sh
+++ b/nixos/modules/installer/tools/nixos-enter.sh
@@ -1,4 +1,4 @@
-#! @shell@
+#! @runtimeShell@
 
 set -e
 
diff --git a/nixos/modules/installer/tools/nixos-generate-config.pl b/nixos/modules/installer/tools/nixos-generate-config.pl
index 422c405054d57..c8303a6eb6020 100644
--- a/nixos/modules/installer/tools/nixos-generate-config.pl
+++ b/nixos/modules/installer/tools/nixos-generate-config.pl
@@ -497,8 +497,8 @@ if (-f $fb_modes_file && -r $fb_modes_file) {
     $modes =~ m/([0-9]+)x([0-9]+)/;
     my $console_width = $1, my $console_height = $2;
     if ($console_width > 1920) {
-        push @attrs, "# High-DPI console";
-        push @attrs, 'console.font = lib.mkDefault "${pkgs.terminus_font}/share/consolefonts/ter-u28n.psf.gz";';
+        push @attrs, "# high-resolution display";
+        push @attrs, 'hardware.video.hidpi.enable = lib.mkDefault true;';
     }
 }
 
@@ -628,6 +628,7 @@ EOF
         write_file($fn, <<EOF);
 @configuration@
 EOF
+        print STDERR "For more hardware-specific settings, see https://github.com/NixOS/nixos-hardware"
     } else {
         print STDERR "warning: not overwriting existing $fn\n";
     }
diff --git a/nixos/modules/installer/tools/nixos-install.sh b/nixos/modules/installer/tools/nixos-install.sh
index 1bccbbfaf245e..a180d1bc4c191 100644
--- a/nixos/modules/installer/tools/nixos-install.sh
+++ b/nixos/modules/installer/tools/nixos-install.sh
@@ -1,4 +1,4 @@
-#! @shell@
+#! @runtimeShell@
 
 set -e
 shopt -s nullglob
@@ -10,6 +10,7 @@ umask 0022
 
 # Parse the command line for the -I flag
 extraBuildFlags=()
+flakeFlags=()
 
 mountPoint=/mnt
 channelPath=
@@ -34,6 +35,23 @@ while [ "$#" -gt 0 ]; do
         --system|--closure)
             system="$1"; shift 1
             ;;
+        --flake)
+          flake="$1"
+          flakeFlags=(--experimental-features 'nix-command flakes')
+          shift 1
+          ;;
+        --recreate-lock-file|--no-update-lock-file|--no-write-lock-file|--no-registries|--commit-lock-file)
+          lockFlags+=("$i")
+          ;;
+        --update-input)
+          j="$1"; shift 1
+          lockFlags+=("$i" "$j")
+          ;;
+        --override-input)
+          j="$1"; shift 1
+          k="$1"; shift 1
+          lockFlags+=("$i" "$j" "$k")
+          ;;
         --channel)
             channelPath="$1"; shift 1
             ;;
@@ -71,6 +89,17 @@ if ! test -e "$mountPoint"; then
     exit 1
 fi
 
+# Verify permissions are okay-enough
+checkPath="$(realpath "$mountPoint")"
+while [[ "$checkPath" != "/" ]]; do
+    mode="$(stat -c '%a' "$checkPath")"
+    if [[ "${mode: -1}" -lt "5" ]]; then
+        echo "path $checkPath should have permissions 755, but had permissions $mode. Consider running 'chmod o+rx $checkPath'."
+        exit 1
+    fi
+    checkPath="$(dirname "$checkPath")"
+done
+
 # Get the path of the NixOS configuration file.
 if [[ -z $NIXOS_CONFIG ]]; then
     NIXOS_CONFIG=$mountPoint/etc/nixos/configuration.nix
@@ -81,14 +110,32 @@ if [[ ${NIXOS_CONFIG:0:1} != / ]]; then
     exit 1
 fi
 
-if [[ ! -e $NIXOS_CONFIG && -z $system ]]; then
+if [[ -n $flake ]]; then
+    if [[ $flake =~ ^(.*)\#([^\#\"]*)$ ]]; then
+       flake="${BASH_REMATCH[1]}"
+       flakeAttr="${BASH_REMATCH[2]}"
+    fi
+    if [[ -z "$flakeAttr" ]]; then
+        echo "Please specify the name of the NixOS configuration to be installed, as a URI fragment in the flake-uri."
+        echo "For example, to use the output nixosConfigurations.foo from the flake.nix, append \"#foo\" to the flake-uri."
+        exit 1
+    fi
+    flakeAttr="nixosConfigurations.\"$flakeAttr\""
+fi
+
+# Resolve the flake.
+if [[ -n $flake ]]; then
+    flake=$(nix "${flakeFlags[@]}" flake info --json "${extraBuildFlags[@]}" "${lockFlags[@]}" -- "$flake" | jq -r .url)
+fi
+
+if [[ ! -e $NIXOS_CONFIG && -z $system && -z $flake ]]; then
     echo "configuration file $NIXOS_CONFIG doesn't exist"
     exit 1
 fi
 
 # A place to drop temporary stuff.
-tmpdir="$(mktemp -d -p $mountPoint)"
-trap "rm -rf $tmpdir" EXIT
+tmpdir="$(mktemp -d -p "$mountPoint")"
+trap 'rm -rf $tmpdir' EXIT
 
 # store temporary files on target filesystem by default
 export TMPDIR=${TMPDIR:-$tmpdir}
@@ -97,12 +144,19 @@ sub="auto?trusted=1"
 
 # Build the system configuration in the target filesystem.
 if [[ -z $system ]]; then
-    echo "building the configuration in $NIXOS_CONFIG..."
     outLink="$tmpdir/system"
-    nix-build --out-link "$outLink" --store "$mountPoint" "${extraBuildFlags[@]}" \
-        --extra-substituters "$sub" \
-        '<nixpkgs/nixos>' -A system -I "nixos-config=$NIXOS_CONFIG" ${verbosity[@]}
-    system=$(readlink -f $outLink)
+    if [[ -z $flake ]]; then
+        echo "building the configuration in $NIXOS_CONFIG..."
+        nix-build --out-link "$outLink" --store "$mountPoint" "${extraBuildFlags[@]}" \
+            --extra-substituters "$sub" \
+            '<nixpkgs/nixos>' -A system -I "nixos-config=$NIXOS_CONFIG" "${verbosity[@]}"
+    else
+        echo "building the flake in $flake..."
+        nix "${flakeFlags[@]}" build "$flake#$flakeAttr.config.system.build.toplevel" \
+            --extra-substituters "$sub" "${verbosity[@]}" \
+            "${extraBuildFlags[@]}" "${lockFlags[@]}" --out-link "$outLink"
+    fi
+    system=$(readlink -f "$outLink")
 fi
 
 # Set the system profile to point to the configuration. TODO: combine
@@ -110,7 +164,7 @@ fi
 # a progress bar.
 nix-env --store "$mountPoint" "${extraBuildFlags[@]}" \
         --extra-substituters "$sub" \
-        -p $mountPoint/nix/var/nix/profiles/system --set "$system" ${verbosity[@]}
+        -p "$mountPoint"/nix/var/nix/profiles/system --set "$system" "${verbosity[@]}"
 
 # Copy the NixOS/Nixpkgs sources to the target as the initial contents
 # of the NixOS channel.
@@ -120,12 +174,12 @@ if [[ -z $noChannelCopy ]]; then
     fi
     if [[ -n $channelPath ]]; then
         echo "copying channel..."
-        mkdir -p $mountPoint/nix/var/nix/profiles/per-user/root
+        mkdir -p "$mountPoint"/nix/var/nix/profiles/per-user/root
         nix-env --store "$mountPoint" "${extraBuildFlags[@]}" --extra-substituters "$sub" \
-                -p $mountPoint/nix/var/nix/profiles/per-user/root/channels --set "$channelPath" --quiet \
-                ${verbosity[@]}
-        install -m 0700 -d $mountPoint/root/.nix-defexpr
-        ln -sfn /nix/var/nix/profiles/per-user/root/channels $mountPoint/root/.nix-defexpr/channels
+                -p "$mountPoint"/nix/var/nix/profiles/per-user/root/channels --set "$channelPath" --quiet \
+                "${verbosity[@]}"
+        install -m 0700 -d "$mountPoint"/root/.nix-defexpr
+        ln -sfn /nix/var/nix/profiles/per-user/root/channels "$mountPoint"/root/.nix-defexpr/channels
     fi
 fi
 
@@ -139,7 +193,7 @@ touch "$mountPoint/etc/NIXOS"
 if [[ -z $noBootLoader ]]; then
     echo "installing the boot loader..."
     # Grub needs an mtab.
-    ln -sfn /proc/mounts $mountPoint/etc/mtab
+    ln -sfn /proc/mounts "$mountPoint"/etc/mtab
     NIXOS_INSTALL_BOOTLOADER=1 nixos-enter --root "$mountPoint" -- /run/current-system/bin/switch-to-configuration boot
 fi
 
diff --git a/nixos/modules/installer/tools/nixos-option/nixos-option.cc b/nixos/modules/installer/tools/nixos-option/nixos-option.cc
index 1a7b07a74f8ac..f779d82edbd6f 100644
--- a/nixos/modules/installer/tools/nixos-option/nixos-option.cc
+++ b/nixos/modules/installer/tools/nixos-option/nixos-option.cc
@@ -224,7 +224,7 @@ bool optionTypeIs(Context & ctx, Value & v, const std::string & soughtType)
 
 bool isAggregateOptionType(Context & ctx, Value & v)
 {
-    return optionTypeIs(ctx, v, "attrsOf") || optionTypeIs(ctx, v, "listOf") || optionTypeIs(ctx, v, "loaOf");
+    return optionTypeIs(ctx, v, "attrsOf") || optionTypeIs(ctx, v, "listOf");
 }
 
 MakeError(OptionPathError, EvalError);
diff --git a/nixos/modules/installer/tools/nixos-rebuild.sh b/nixos/modules/installer/tools/nixos-rebuild.sh
index 354274478a384..909e8b229c8ab 100644
--- a/nixos/modules/installer/tools/nixos-rebuild.sh
+++ b/nixos/modules/installer/tools/nixos-rebuild.sh
@@ -1,6 +1,6 @@
-#! @shell@
+#! @runtimeShell@
 
-if [ -x "@shell@" ]; then export SHELL="@shell@"; fi;
+if [ -x "@runtimeShell@" ]; then export SHELL="@runtimeShell@"; fi;
 
 set -e
 set -o pipefail
@@ -17,6 +17,7 @@ showSyntax() {
 origArgs=("$@")
 extraBuildFlags=()
 lockFlags=()
+flakeFlags=()
 action=
 buildNix=1
 fast=
@@ -99,6 +100,7 @@ while [ "$#" -gt 0 ]; do
         ;;
       --flake)
         flake="$1"
+        flakeFlags=(--experimental-features 'nix-command flakes')
         shift 1
         ;;
       --recreate-lock-file|--no-update-lock-file|--no-write-lock-file|--no-registries|--commit-lock-file)
@@ -281,16 +283,19 @@ fi
 
 # Resolve the flake.
 if [[ -n $flake ]]; then
-    flake=$(nix flake info --json "${extraBuildFlags[@]}" "${lockFlags[@]}" -- "$flake" | jq -r .url)
+    flake=$(nix "${flakeFlags[@]}" flake info --json "${extraBuildFlags[@]}" "${lockFlags[@]}" -- "$flake" | jq -r .url)
 fi
 
 # Find configuration.nix and open editor instead of building.
 if [ "$action" = edit ]; then
     if [[ -z $flake ]]; then
         NIXOS_CONFIG=${NIXOS_CONFIG:-$(nix-instantiate --find-file nixos-config)}
-        exec "${EDITOR:-nano}" "$NIXOS_CONFIG"
+        if [[ -d $NIXOS_CONFIG ]]; then
+            NIXOS_CONFIG=$NIXOS_CONFIG/default.nix
+        fi
+        exec ${EDITOR:-nano} "$NIXOS_CONFIG"
     else
-        exec nix edit "${lockFlags[@]}" -- "$flake#$flakeAttr"
+        exec nix "${flakeFlags[@]}" edit "${lockFlags[@]}" -- "$flake#$flakeAttr"
     fi
     exit 1
 fi
@@ -416,7 +421,7 @@ if [ -z "$rollback" ]; then
             pathToConfig="$(nixBuild '<nixpkgs/nixos>' --no-out-link -A system "${extraBuildFlags[@]}")"
         else
             outLink=$tmpDir/result
-            nix build "$flake#$flakeAttr.config.system.build.toplevel" \
+            nix "${flakeFlags[@]}" build "$flake#$flakeAttr.config.system.build.toplevel" \
               "${extraBuildFlags[@]}" "${lockFlags[@]}" --out-link $outLink
             pathToConfig="$(readlink -f $outLink)"
         fi
@@ -426,22 +431,24 @@ if [ -z "$rollback" ]; then
         if [[ -z $flake ]]; then
             pathToConfig="$(nixBuild '<nixpkgs/nixos>' -A system -k "${extraBuildFlags[@]}")"
         else
-            nix build "$flake#$flakeAttr.config.system.build.toplevel" "${extraBuildFlags[@]}" "${lockFlags[@]}"
+            nix "${flakeFlags[@]}" build "$flake#$flakeAttr.config.system.build.toplevel" "${extraBuildFlags[@]}" "${lockFlags[@]}"
             pathToConfig="$(readlink -f ./result)"
         fi
     elif [ "$action" = build-vm ]; then
         if [[ -z $flake ]]; then
             pathToConfig="$(nixBuild '<nixpkgs/nixos>' -A vm -k "${extraBuildFlags[@]}")"
         else
-            echo "$0: 'build-vm' is not supported with '--flake'" >&2
-            exit 1
+            nix "${flakeFlags[@]}" build "$flake#$flakeAttr.config.system.build.vm" \
+              "${extraBuildFlags[@]}" "${lockFlags[@]}"
+            pathToConfig="$(readlink -f ./result)"
         fi
     elif [ "$action" = build-vm-with-bootloader ]; then
         if [[ -z $flake ]]; then
             pathToConfig="$(nixBuild '<nixpkgs/nixos>' -A vmWithBootLoader -k "${extraBuildFlags[@]}")"
         else
-            echo "$0: 'build-vm-with-bootloader' is not supported with '--flake'" >&2
-            exit 1
+            nix "${flakeFlags[@]}" build "$flake#$flakeAttr.config.system.build.vmWithBootLoader" \
+              "${extraBuildFlags[@]}" "${lockFlags[@]}"
+            pathToConfig="$(readlink -f ./result)"
         fi
     else
         showSyntax
diff --git a/nixos/modules/installer/tools/nixos-version.sh b/nixos/modules/installer/tools/nixos-version.sh
index fb0fe26116a6e..f5e3f32b3c632 100644
--- a/nixos/modules/installer/tools/nixos-version.sh
+++ b/nixos/modules/installer/tools/nixos-version.sh
@@ -1,4 +1,4 @@
-#! @shell@
+#! @runtimeShell@
 
 case "$1" in
   -h|--help)
diff --git a/nixos/modules/installer/tools/tools.nix b/nixos/modules/installer/tools/tools.nix
index 111286214248d..e1e1b47aafcb9 100644
--- a/nixos/modules/installer/tools/tools.nix
+++ b/nixos/modules/installer/tools/tools.nix
@@ -14,13 +14,19 @@ let
   nixos-build-vms = makeProg {
     name = "nixos-build-vms";
     src = ./nixos-build-vms/nixos-build-vms.sh;
+    inherit (pkgs) runtimeShell;
   };
 
   nixos-install = makeProg {
     name = "nixos-install";
     src = ./nixos-install.sh;
+    inherit (pkgs) runtimeShell;
     nix = config.nix.package.out;
-    path = makeBinPath [ nixos-enter ];
+    path = makeBinPath [
+      pkgs.nixUnstable
+      pkgs.jq
+      nixos-enter
+    ];
   };
 
   nixos-rebuild =
@@ -28,6 +34,7 @@ let
     makeProg {
       name = "nixos-rebuild";
       src = ./nixos-rebuild.sh;
+      inherit (pkgs) runtimeShell;
       nix = config.nix.package.out;
       nix_x86_64_linux = fallback.x86_64-linux;
       nix_i686_linux = fallback.i686-linux;
@@ -50,6 +57,7 @@ let
   nixos-version = makeProg {
     name = "nixos-version";
     src = ./nixos-version.sh;
+    inherit (pkgs) runtimeShell;
     inherit (config.system.nixos) version codeName revision;
     inherit (config.system) configurationRevision;
     json = builtins.toJSON ({
@@ -64,6 +72,7 @@ let
   nixos-enter = makeProg {
     name = "nixos-enter";
     src = ./nixos-enter.sh;
+    inherit (pkgs) runtimeShell;
   };
 
 in
diff --git a/nixos/modules/misc/documentation.nix b/nixos/modules/misc/documentation.nix
index 7ad4be9a02e69..71a40b4f4d6e2 100644
--- a/nixos/modules/misc/documentation.nix
+++ b/nixos/modules/misc/documentation.nix
@@ -102,6 +102,16 @@ in
         '';
       };
 
+      man.generateCaches = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to generate the manual page index caches using
+          <literal>mandb(8)</literal>. This allows searching for a page or
+          keyword using utilities like <literal>apropos(1)</literal>.
+        '';
+      };
+
       info.enable = mkOption {
         type = types.bool;
         default = true;
@@ -187,7 +197,33 @@ in
       environment.systemPackages = [ pkgs.man-db ];
       environment.pathsToLink = [ "/share/man" ];
       environment.extraOutputsToInstall = [ "man" ] ++ optional cfg.dev.enable "devman";
-      environment.etc."man.conf".source = "${pkgs.man-db}/etc/man_db.conf";
+      environment.etc."man_db.conf".text =
+        let
+          manualPages = pkgs.buildEnv {
+            name = "man-paths";
+            paths = config.environment.systemPackages;
+            pathsToLink = [ "/share/man" ];
+            extraOutputsToInstall = ["man"];
+            ignoreCollisions = true;
+          };
+          manualCache = pkgs.runCommandLocal "man-cache" { }
+          ''
+            echo "MANDB_MAP ${manualPages}/share/man $out" > man.conf
+            ${pkgs.man-db}/bin/mandb -C man.conf -psc
+          '';
+        in
+        ''
+          # Manual pages paths for NixOS
+          MANPATH_MAP /run/current-system/sw/bin /run/current-system/sw/share/man
+          MANPATH_MAP /run/wrappers/bin          /run/current-system/sw/share/man
+
+          ${optionalString cfg.man.generateCaches ''
+          # Generated manual pages cache for NixOS (immutable)
+          MANDB_MAP /run/current-system/sw/share/man ${manualCache}
+          ''}
+          # Manual pages caches for NixOS
+          MANDB_MAP /run/current-system/sw/share/man /var/cache/man/nixos
+        '';
     })
 
     (mkIf cfg.info.enable {
diff --git a/nixos/modules/misc/ids.nix b/nixos/modules/misc/ids.nix
index 3409e7ba22ea4..3fabe8b42c97a 100644
--- a/nixos/modules/misc/ids.nix
+++ b/nixos/modules/misc/ids.nix
@@ -184,7 +184,7 @@ in
       consul = 145;
       mailpile = 146;
       redmine = 147;
-      seeks = 148;
+      #seeks = 148; # removed 2020-06-21
       prosody = 149;
       i2pd = 150;
       systemd-network = 152;
@@ -198,7 +198,7 @@ in
       bosun = 161;
       kubernetes = 162;
       peerflix = 163;
-      chronos = 164;
+      #chronos = 164; # removed 2020-08-15
       gitlab = 165;
       tox-bootstrapd = 166;
       cadvisor = 167;
@@ -247,7 +247,7 @@ in
       bepasty = 215;
       # pumpio = 216; # unused, removed 2018-02-24
       nm-openvpn = 217;
-      mathics = 218;
+      # mathics = 218; # unused, removed 2020-08-15
       ejabberd = 219;
       postsrsd = 220;
       opendkim = 221;
@@ -321,7 +321,7 @@ in
       monetdb = 290;
       restic = 291;
       openvpn = 292;
-      meguca = 293;
+      # meguca = 293; # removed 2020-08-21
       yarn = 294;
       hdfs = 295;
       mapred = 296;
@@ -345,6 +345,7 @@ in
       zoneminder = 314;
       paperless = 315;
       #mailman = 316;  # removed 2019-08-30
+      zigbee2mqtt = 317;
 
       # When adding a uid, make sure it doesn't match an existing gid. And don't use uids above 399!
 
@@ -496,7 +497,7 @@ in
       #consul = 145; # unused
       mailpile = 146;
       redmine = 147;
-      seeks = 148;
+      #seeks = 148; # removed 2020-06-21
       prosody = 149;
       i2pd = 150;
       systemd-network = 152;
@@ -621,7 +622,7 @@ in
       monetdb = 290;
       restic = 291;
       openvpn = 292;
-      meguca = 293;
+      # meguca = 293; # removed 2020-08-21
       yarn = 294;
       hdfs = 295;
       mapred = 296;
@@ -645,6 +646,7 @@ in
       zoneminder = 314;
       paperless = 315;
       #mailman = 316;  # removed 2019-08-30
+      zigbee2mqtt = 317;
 
       # When adding a gid, make sure it doesn't match an existing
       # uid. Users and groups with the same name should have equal
diff --git a/nixos/modules/misc/locate.nix b/nixos/modules/misc/locate.nix
index dc668796c7886..92aa3be0a3667 100644
--- a/nixos/modules/misc/locate.nix
+++ b/nixos/modules/misc/locate.nix
@@ -127,7 +127,7 @@ in {
       { LOCATE_PATH = cfg.output;
       };
 
-    warnings = optional (isMLocate && cfg.localuser != null) "mlocate does not support searching as user other than root"
+    warnings = optional (isMLocate && cfg.localuser != null) "mlocate does not support the services.locate.localuser option; updatedb will run as root. (Silence with services.locate.localuser = null.)"
             ++ optional (isFindutils && cfg.pruneNames != []) "findutils locate does not support pruning by directory component"
             ++ optional (isFindutils && cfg.pruneBindMounts) "findutils locate does not support skipping bind mounts";
 
diff --git a/nixos/modules/misc/nixpkgs.nix b/nixos/modules/misc/nixpkgs.nix
index 4f5a9250eaaee..25ac94b8e0f65 100644
--- a/nixos/modules/misc/nixpkgs.nix
+++ b/nixos/modules/misc/nixpkgs.nix
@@ -178,8 +178,6 @@ in
       type = types.nullOr types.attrs; # TODO utilize lib.systems.parsedPlatform
       default = null;
       example = { system = "aarch64-linux"; config = "aarch64-unknown-linux-gnu"; };
-      defaultText = literalExample
-        ''(import "''${nixos}/../lib").lib.systems.examples.aarch64-multiplatform'';
       description = ''
         Specifies the platform for which NixOS should be
         built. Specify this only if it is different from
diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix
index 448d432853d34..e7e5fbb4f3f27 100644
--- a/nixos/modules/module-list.nix
+++ b/nixos/modules/module-list.nix
@@ -1,7 +1,6 @@
 [
   ./config/debug-info.nix
   ./config/fonts/fontconfig.nix
-  ./config/fonts/fontconfig-penultimate.nix
   ./config/fonts/fontdir.nix
   ./config/fonts/fonts.nix
   ./config/fonts/ghostscript.nix
@@ -72,9 +71,11 @@
   ./hardware/video/capture/mwprocapture.nix
   ./hardware/video/bumblebee.nix
   ./hardware/video/displaylink.nix
+  ./hardware/video/hidpi.nix
   ./hardware/video/nvidia.nix
   ./hardware/video/uvcvideo/default.nix
   ./hardware/video/webcam/facetimehd.nix
+  ./hardware/xpadneo.nix
   ./i18n/input-method/default.nix
   ./i18n/input-method/fcitx.nix
   ./i18n/input-method/ibus.nix
@@ -154,6 +155,7 @@
   ./programs/ssmtp.nix
   ./programs/sysdig.nix
   ./programs/systemtap.nix
+  ./programs/steam.nix
   ./programs/sway.nix
   ./programs/system-config-printer.nix
   ./programs/thefuck.nix
@@ -260,6 +262,7 @@
   ./services/continuous-integration/buildbot/worker.nix
   ./services/continuous-integration/buildkite-agents.nix
   ./services/continuous-integration/hail.nix
+  ./services/continuous-integration/hercules-ci-agent/default.nix
   ./services/continuous-integration/hydra/default.nix
   ./services/continuous-integration/gitlab-runner.nix
   ./services/continuous-integration/gocd-agent/default.nix
@@ -294,10 +297,10 @@
   ./services/desktops/accountsservice.nix
   ./services/desktops/bamf.nix
   ./services/desktops/blueman.nix
-  ./services/desktops/deepin/deepin.nix
   ./services/desktops/dleyna-renderer.nix
   ./services/desktops/dleyna-server.nix
   ./services/desktops/pantheon/files.nix
+  ./services/desktops/espanso.nix
   ./services/desktops/flatpak.nix
   ./services/desktops/geoclue2.nix
   ./services/desktops/gsignond.nix
@@ -328,6 +331,7 @@
   ./services/development/bloop.nix
   ./services/development/hoogle.nix
   ./services/development/jupyter/default.nix
+  ./services/development/jupyterhub/default.nix
   ./services/development/lorri.nix
   ./services/editors/emacs.nix
   ./services/editors/infinoted.nix
@@ -462,14 +466,11 @@
   ./services/misc/leaps.nix
   ./services/misc/lidarr.nix
   ./services/misc/mame.nix
-  ./services/misc/mathics.nix
   ./services/misc/matrix-appservice-discord.nix
   ./services/misc/matrix-synapse.nix
   ./services/misc/mautrix-telegram.nix
   ./services/misc/mbpfan.nix
   ./services/misc/mediatomb.nix
-  ./services/misc/mesos-master.nix
-  ./services/misc/mesos-slave.nix
   ./services/misc/metabase.nix
   ./services/misc/mwlib.nix
   ./services/misc/nix-daemon.nix
@@ -485,6 +486,7 @@
   ./services/misc/parsoid.nix
   ./services/misc/plex.nix
   ./services/misc/tautulli.nix
+  ./services/misc/pinnwand.nix
   ./services/misc/pykms.nix
   ./services/misc/radarr.nix
   ./services/misc/redmine.nix
@@ -510,6 +512,7 @@
   ./services/misc/uhub.nix
   ./services/misc/weechat.nix
   ./services/misc/xmr-stak.nix
+  ./services/misc/zigbee2mqtt.nix
   ./services/misc/zoneminder.nix
   ./services/misc/zookeeper.nix
   ./services/monitoring/alerta.nix
@@ -551,6 +554,7 @@
   ./services/monitoring/telegraf.nix
   ./services/monitoring/thanos.nix
   ./services/monitoring/tuptime.nix
+  ./services/monitoring/unifi-poller.nix
   ./services/monitoring/ups.nix
   ./services/monitoring/uptime.nix
   ./services/monitoring/vnstat.nix
@@ -584,11 +588,13 @@
   ./services/networking/atftpd.nix
   ./services/networking/avahi-daemon.nix
   ./services/networking/babeld.nix
+  ./services/networking/biboumi.nix
   ./services/networking/bind.nix
   ./services/networking/bitcoind.nix
   ./services/networking/autossh.nix
   ./services/networking/bird.nix
   ./services/networking/bitlbee.nix
+  ./services/networking/blockbook-frontend.nix
   ./services/networking/charybdis.nix
   ./services/networking/cjdns.nix
   ./services/networking/cntlm.nix
@@ -606,6 +612,7 @@
   ./services/networking/dnscrypt-wrapper.nix
   ./services/networking/dnsdist.nix
   ./services/networking/dnsmasq.nix
+  ./services/networking/ncdns.nix
   ./services/networking/ejabberd.nix
   ./services/networking/epmd.nix
   ./services/networking/ergo.nix
@@ -630,7 +637,6 @@
   ./services/networking/gvpe.nix
   ./services/networking/hans.nix
   ./services/networking/haproxy.nix
-  ./services/networking/heyefi.nix
   ./services/networking/hostapd.nix
   ./services/networking/htpdate.nix
   ./services/networking/hylafax/default.nix
@@ -640,6 +646,8 @@
   ./services/networking/iperf3.nix
   ./services/networking/ircd-hybrid/default.nix
   ./services/networking/iwd.nix
+  ./services/networking/jicofo.nix
+  ./services/networking/jitsi-videobridge.nix
   ./services/networking/keepalived/default.nix
   ./services/networking/keybase.nix
   ./services/networking/kippo.nix
@@ -668,6 +676,7 @@
   ./services/networking/nat.nix
   ./services/networking/ndppd.nix
   ./services/networking/networkmanager.nix
+  ./services/networking/nextdns.nix
   ./services/networking/nftables.nix
   ./services/networking/ngircd.nix
   ./services/networking/nghttpx/default.nix
@@ -685,6 +694,7 @@
   ./services/networking/ocserv.nix
   ./services/networking/ofono.nix
   ./services/networking/oidentd.nix
+  ./services/networking/onedrive.nix
   ./services/networking/openfire.nix
   ./services/networking/openvpn.nix
   ./services/networking/ostinato.nix
@@ -709,11 +719,11 @@
   ./services/networking/rdnssd.nix
   ./services/networking/redsocks.nix
   ./services/networking/resilio.nix
+  ./services/networking/robustirc-bridge.nix
   ./services/networking/rpcbind.nix
   ./services/networking/rxe.nix
   ./services/networking/sabnzbd.nix
   ./services/networking/searx.nix
-  ./services/networking/seeks.nix
   ./services/networking/skydns.nix
   ./services/networking/shadowsocks.nix
   ./services/networking/shairport-sync.nix
@@ -757,6 +767,7 @@
   ./services/networking/v2ray.nix
   ./services/networking/vsftpd.nix
   ./services/networking/wakeonlan.nix
+  ./services/networking/wasabibackend.nix
   ./services/networking/websockify.nix
   ./services/networking/wg-quick.nix
   ./services/networking/wicd.nix
@@ -773,10 +784,8 @@
   ./services/networking/znc/default.nix
   ./services/printing/cupsd.nix
   ./services/scheduling/atd.nix
-  ./services/scheduling/chronos.nix
   ./services/scheduling/cron.nix
   ./services/scheduling/fcron.nix
-  ./services/scheduling/marathon.nix
   ./services/search/elasticsearch.nix
   ./services/search/elasticsearch-curator.nix
   ./services/search/hound.nix
@@ -807,6 +816,7 @@
   ./services/security/torsocks.nix
   ./services/security/usbguard.nix
   ./services/security/vault.nix
+  ./services/security/yubikey-agent.nix
   ./services/system/cloud-init.nix
   ./services/system/dbus.nix
   ./services/system/earlyoom.nix
@@ -826,10 +836,13 @@
   ./services/ttys/gpm.nix
   ./services/ttys/kmscon.nix
   ./services/wayland/cage.nix
+  ./services/video/epgstation/default.nix
+  ./services/video/mirakurun.nix
   ./services/web-apps/atlassian/confluence.nix
   ./services/web-apps/atlassian/crowd.nix
   ./services/web-apps/atlassian/jira.nix
   ./services/web-apps/codimd.nix
+  ./services/web-apps/convos.nix
   ./services/web-apps/cryptpad.nix
   ./services/web-apps/documize.nix
   ./services/web-apps/dokuwiki.nix
@@ -842,6 +855,7 @@
   ./services/web-apps/icingaweb2/module-monitoring.nix
   ./services/web-apps/ihatemoney
   ./services/web-apps/jirafeau.nix
+  ./services/web-apps/jitsi-meet.nix
   ./services/web-apps/limesurvey.nix
   ./services/web-apps/mattermost.nix
   ./services/web-apps/mediawiki.nix
@@ -854,6 +868,7 @@
   ./services/web-apps/moinmoin.nix
   ./services/web-apps/restya-board.nix
   ./services/web-apps/sogo.nix
+  ./services/web-apps/rss-bridge.nix
   ./services/web-apps/tt-rss.nix
   ./services/web-apps/trac.nix
   ./services/web-apps/trilium.nix
@@ -874,9 +889,9 @@
   ./services/web-servers/lighttpd/collectd.nix
   ./services/web-servers/lighttpd/default.nix
   ./services/web-servers/lighttpd/gitweb.nix
-  ./services/web-servers/meguca.nix
   ./services/web-servers/mighttpd2.nix
   ./services/web-servers/minio.nix
+  ./services/web-servers/molly-brown.nix
   ./services/web-servers/nginx/default.nix
   ./services/web-servers/nginx/gitweb.nix
   ./services/web-servers/phpfpm/default.nix
@@ -911,6 +926,7 @@
   ./services/x11/gdk-pixbuf.nix
   ./services/x11/imwheel.nix
   ./services/x11/redshift.nix
+  ./services/x11/urserver.nix
   ./services/x11/urxvtd.nix
   ./services/x11/window-managers/awesome.nix
   ./services/x11/window-managers/default.nix
@@ -934,6 +950,7 @@
   ./system/boot/grow-partition.nix
   ./system/boot/initrd-network.nix
   ./system/boot/initrd-ssh.nix
+  ./system/boot/initrd-openvpn.nix
   ./system/boot/kernel.nix
   ./system/boot/kexec.nix
   ./system/boot/loader/efi.nix
@@ -1009,6 +1026,7 @@
   ./virtualisation/podman.nix
   ./virtualisation/qemu-guest-agent.nix
   ./virtualisation/railcar.nix
+  ./virtualisation/spice-usb-redirection.nix
   ./virtualisation/virtualbox-guest.nix
   ./virtualisation/virtualbox-host.nix
   ./virtualisation/vmware-guest.nix
diff --git a/nixos/modules/profiles/base.nix b/nixos/modules/profiles/base.nix
index 2a2fe119d30cb..3b67d628f9fd7 100644
--- a/nixos/modules/profiles/base.nix
+++ b/nixos/modules/profiles/base.nix
@@ -26,6 +26,7 @@
     pkgs.fuse
     pkgs.fuse3
     pkgs.sshfs-fuse
+    pkgs.rsync
     pkgs.socat
     pkgs.screen
 
diff --git a/nixos/modules/profiles/demo.nix b/nixos/modules/profiles/demo.nix
index 18f190071bad8..4e8c74deedba3 100644
--- a/nixos/modules/profiles/demo.nix
+++ b/nixos/modules/profiles/demo.nix
@@ -11,9 +11,11 @@
       uid = 1000;
     };
 
-  services.xserver.displayManager.sddm.autoLogin = {
-    enable = true;
-    relogin = true;
-    user = "demo";
+  services.xserver.displayManager = {
+    autoLogin = {
+      enable = true;
+      user = "demo";
+    };
+    sddm.autoLogin.relogin = true;
   };
 }
diff --git a/nixos/modules/profiles/hardened.nix b/nixos/modules/profiles/hardened.nix
index ef8c0d74f0628..7bff79e827302 100644
--- a/nixos/modules/profiles/hardened.nix
+++ b/nixos/modules/profiles/hardened.nix
@@ -1,7 +1,7 @@
 # A profile with most (vanilla) hardening options enabled by default,
 # potentially at the cost of features and performance.
 
-{ lib, pkgs, ... }:
+{ config, lib, pkgs, ... }:
 
 with lib;
 
@@ -27,6 +27,9 @@ with lib;
 
   security.forcePageTableIsolation = mkDefault true;
 
+  # This is required by podman to run containers in rootless mode.
+  security.unprivilegedUsernsClone = mkDefault config.virtualisation.containers.enable;
+
   security.virtualisation.flushL1DataCache = mkDefault "always";
 
   security.apparmor.enable = mkDefault true;
diff --git a/nixos/modules/profiles/installation-device.nix b/nixos/modules/profiles/installation-device.nix
index d05c0c50e82c1..e68ea1b08776a 100644
--- a/nixos/modules/profiles/installation-device.nix
+++ b/nixos/modules/profiles/installation-device.nix
@@ -51,22 +51,23 @@ with lib;
     services.mingetty.helpLine = ''
       The "nixos" and "root" accounts have empty passwords.
 
-      Type `sudo systemctl start sshd` to start the SSH daemon.
-      You then must set a password for either "root" or "nixos"
-      with `passwd` to be able to login.
+      An ssh daemon is running. You then must set a password
+      for either "root" or "nixos" with `passwd` or add an ssh key
+      to /home/nixos/.ssh/authorized_keys be able to login.
     '' + optionalString config.services.xserver.enable ''
       Type `sudo systemctl start display-manager' to
       start the graphical user interface.
     '';
 
-    # Allow sshd to be started manually through "systemctl start sshd".
+    # We run sshd by default. Login via root is only possible after adding a
+    # password via "passwd" or by adding a ssh key to /home/nixos/.ssh/authorized_keys.
+    # The latter one is particular useful if keys are manually added to
+    # installation device for head-less systems i.e. arm boards by manually
+    # mounting the storage in a different system.
     services.openssh = {
       enable = true;
-      # Allow password login to the installation, if the user sets a password via "passwd"
-      # It is safe as root doesn't have a password by default and SSH is disabled by default
       permitRootLogin = "yes";
     };
-    systemd.services.sshd.wantedBy = mkOverride 50 [];
 
     # Enable wpa_supplicant, but don't start it by default.
     networking.wireless.enable = mkDefault true;
diff --git a/nixos/modules/programs/autojump.nix b/nixos/modules/programs/autojump.nix
index 3a8feec4bb45f..ecfc2f658079d 100644
--- a/nixos/modules/programs/autojump.nix
+++ b/nixos/modules/programs/autojump.nix
@@ -18,7 +18,7 @@ in
         '';
       };
     };
-  }; 
+  };
 
   ###### implementation
 
@@ -26,7 +26,7 @@ in
     environment.pathsToLink = [ "/share/autojump" ];
     environment.systemPackages = [ pkgs.autojump ];
 
-    programs.bash.interactiveShellInit = "source ${pkgs.autojump}/share/autojump/autojump.bash"; 
+    programs.bash.interactiveShellInit = "source ${pkgs.autojump}/share/autojump/autojump.bash";
     programs.zsh.interactiveShellInit = mkIf prg.zsh.enable "source ${pkgs.autojump}/share/autojump/autojump.zsh";
     programs.fish.interactiveShellInit = mkIf prg.fish.enable "source ${pkgs.autojump}/share/autojump/autojump.fish";
   };
diff --git a/nixos/modules/programs/ccache.nix b/nixos/modules/programs/ccache.nix
index 874774c72b47c..3c9e64932f16e 100644
--- a/nixos/modules/programs/ccache.nix
+++ b/nixos/modules/programs/ccache.nix
@@ -80,4 +80,4 @@ in {
       ];
     })
   ];
-}
\ No newline at end of file
+}
diff --git a/nixos/modules/programs/dconf.nix b/nixos/modules/programs/dconf.nix
index 6702e8efd1cb4..ec85cb9d18c91 100644
--- a/nixos/modules/programs/dconf.nix
+++ b/nixos/modules/programs/dconf.nix
@@ -4,13 +4,24 @@ with lib;
 
 let
   cfg = config.programs.dconf;
-
-  mkDconfProfile = name: path:
-    {
-      name = "dconf/profile/${name}";
-      value.source = path; 
-    };
-
+  cfgDir = pkgs.symlinkJoin {
+    name = "dconf-system-config";
+    paths = map (x: "${x}/etc/dconf") cfg.packages;
+    postBuild = ''
+      mkdir -p $out/profile
+      mkdir -p $out/db
+    '' + (
+      concatStringsSep "\n" (
+        mapAttrsToList (
+          name: path: ''
+            ln -s ${path} $out/profile/${name}
+          ''
+        ) cfg.profiles
+      )
+    ) + ''
+      ${pkgs.dconf}/bin/dconf update $out/db
+    '';
+  };
 in
 {
   ###### interface
@@ -22,18 +33,24 @@ in
       profiles = mkOption {
         type = types.attrsOf types.path;
         default = {};
-        description = "Set of dconf profile files.";
+        description = "Set of dconf profile files, installed at <filename>/etc/dconf/profiles/<replaceable>name</replaceable></filename>.";
         internal = true;
       };
 
+      packages = mkOption {
+        type = types.listOf types.package;
+        default = [];
+        description = "A list of packages which provide dconf profiles and databases in <filename>/etc/dconf</filename>.";
+      };
     };
   };
 
   ###### implementation
 
   config = mkIf (cfg.profiles != {} || cfg.enable) {
-    environment.etc = optionalAttrs (cfg.profiles != {})
-      (mapAttrs' mkDconfProfile cfg.profiles);
+    environment.etc.dconf = mkIf (cfg.profiles != {} || cfg.packages != []) {
+      source = cfgDir;
+    };
 
     services.dbus.packages = [ pkgs.dconf ];
 
diff --git a/nixos/modules/programs/environment.nix b/nixos/modules/programs/environment.nix
index 38bdabb4fa812..8877356360a5b 100644
--- a/nixos/modules/programs/environment.nix
+++ b/nixos/modules/programs/environment.nix
@@ -33,7 +33,6 @@ in
       { PATH = [ "/bin" ];
         INFOPATH = [ "/info" "/share/info" ];
         KDEDIRS = [ "" ];
-        STRIGI_PLUGIN_PATH = [ "/lib/strigi/" ];
         QT_PLUGIN_PATH = [ "/lib/qt4/plugins" "/lib/kde4/plugins" ];
         QTWEBKIT_PLUGIN_PATH = [ "/lib/mozilla/plugins/" ];
         GTK_PATH = [ "/lib/gtk-2.0" "/lib/gtk-3.0" ];
diff --git a/nixos/modules/programs/fish.nix b/nixos/modules/programs/fish.nix
index 48b324a0fe83c..39b92edf2ac2e 100644
--- a/nixos/modules/programs/fish.nix
+++ b/nixos/modules/programs/fish.nix
@@ -102,6 +102,9 @@ in
 
     programs.fish.shellAliases = mapAttrs (name: mkDefault) cfge.shellAliases;
 
+    # Required for man completions
+    documentation.man.generateCaches = true;
+
     environment.etc."fish/foreign-env/shellInit".text = cfge.shellInit;
     environment.etc."fish/foreign-env/loginShellInit".text = cfge.loginShellInit;
     environment.etc."fish/foreign-env/interactiveShellInit".text = cfge.interactiveShellInit;
diff --git a/nixos/modules/programs/freetds.nix b/nixos/modules/programs/freetds.nix
index e0860a242b741..b4b657e391bf9 100644
--- a/nixos/modules/programs/freetds.nix
+++ b/nixos/modules/programs/freetds.nix
@@ -25,7 +25,7 @@ in
           ''';
         }
       '';
-      description = 
+      description =
         ''
         Configure freetds database entries. Each attribute denotes
         a section within freetds.conf, and the value (a string) is the config
@@ -47,7 +47,7 @@ in
     environment.variables.FREETDS = "/etc/freetds.conf";
     environment.variables.SYBASE = "${pkgs.freetds}";
 
-    environment.etc."freetds.conf" = { text = 
+    environment.etc."freetds.conf" = { text =
       (concatStrings (mapAttrsToList (name: value:
         ''
         [${name}]
diff --git a/nixos/modules/programs/gnupg.nix b/nixos/modules/programs/gnupg.nix
index 7a3cb588ee719..ce8799b21d692 100644
--- a/nixos/modules/programs/gnupg.nix
+++ b/nixos/modules/programs/gnupg.nix
@@ -70,6 +70,7 @@ in
     agent.pinentryFlavor = mkOption {
       type = types.nullOr (types.enum pkgs.pinentry.flavors);
       example = "gnome3";
+      default = defaultPinentryFlavor;
       description = ''
         Which pinentry interface to use. If not null, the path to the
         pinentry binary will be passed to gpg-agent via commandline and
@@ -91,8 +92,6 @@ in
   };
 
   config = mkIf cfg.agent.enable {
-    programs.gnupg.agent.pinentryFlavor = mkDefault defaultPinentryFlavor;
-
     # This overrides the systemd user unit shipped with the gnupg package
     systemd.user.services.gpg-agent = mkIf (cfg.agent.pinentryFlavor != null) {
       serviceConfig.ExecStart = [ "" ''
diff --git a/nixos/modules/programs/gpaste.nix b/nixos/modules/programs/gpaste.nix
index 4f6deb77e5ebc..8bc52c28d814b 100644
--- a/nixos/modules/programs/gpaste.nix
+++ b/nixos/modules/programs/gpaste.nix
@@ -30,5 +30,7 @@ with lib;
     environment.systemPackages = [ pkgs.gnome3.gpaste ];
     services.dbus.packages = [ pkgs.gnome3.gpaste ];
     systemd.packages = [ pkgs.gnome3.gpaste ];
+    # gnome-control-center crashes in Keyboard Shortcuts pane without the GSettings schemas.
+    services.xserver.desktopManager.gnome3.sessionPath = [ pkgs.gnome3.gpaste ];
   };
 }
diff --git a/nixos/modules/programs/nm-applet.nix b/nixos/modules/programs/nm-applet.nix
index 273a6dec59a58..5bcee30125bb8 100644
--- a/nixos/modules/programs/nm-applet.nix
+++ b/nixos/modules/programs/nm-applet.nix
@@ -5,14 +5,25 @@
     maintainers = lib.teams.freedesktop.members;
   };
 
-  options.programs.nm-applet.enable = lib.mkEnableOption "nm-applet";
+  options.programs.nm-applet = {
+    enable = lib.mkEnableOption "nm-applet";
+
+    indicator = lib.mkOption {
+      type = lib.types.bool;
+      default = true;
+      description = ''
+        Whether to use indicator instead of status icon.
+        It is needed for Appindicator environments, like Enlightenment.
+      '';
+    };
+  };
 
   config = lib.mkIf config.programs.nm-applet.enable {
     systemd.user.services.nm-applet = {
       description = "Network manager applet";
       wantedBy = [ "graphical-session.target" ];
       partOf = [ "graphical-session.target" ];
-      serviceConfig.ExecStart = "${pkgs.networkmanagerapplet}/bin/nm-applet";
+      serviceConfig.ExecStart = "${pkgs.networkmanagerapplet}/bin/nm-applet ${lib.optionalString config.programs.nm-applet.indicator "--indicator"}";
     };
 
     services.dbus.packages = [ pkgs.gcr ];
diff --git a/nixos/modules/programs/qt5ct.nix b/nixos/modules/programs/qt5ct.nix
index aeb7fc5084954..3f2bcf6228369 100644
--- a/nixos/modules/programs/qt5ct.nix
+++ b/nixos/modules/programs/qt5ct.nix
@@ -26,6 +26,6 @@ with lib;
   ###### implementation
   config = mkIf config.programs.qt5ct.enable {
     environment.variables.QT_QPA_PLATFORMTHEME = "qt5ct";
-    environment.systemPackages = with pkgs; [ qt5ct libsForQt5.qtstyleplugins ];
+    environment.systemPackages = with pkgs; [ qt5ct ];
   };
 }
diff --git a/nixos/modules/programs/ssh.nix b/nixos/modules/programs/ssh.nix
index a983ffa4b890f..40af4d0ff5aeb 100644
--- a/nixos/modules/programs/ssh.nix
+++ b/nixos/modules/programs/ssh.nix
@@ -131,7 +131,7 @@ in
 
       knownHosts = mkOption {
         default = {};
-        type = types.loaOf (types.submodule ({ name, ... }: {
+        type = types.attrsOf (types.submodule ({ name, ... }: {
           options = {
             certAuthority = mkOption {
               type = types.bool;
diff --git a/nixos/modules/programs/steam.nix b/nixos/modules/programs/steam.nix
new file mode 100644
index 0000000000000..3c919c47a0c61
--- /dev/null
+++ b/nixos/modules/programs/steam.nix
@@ -0,0 +1,25 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.programs.steam;
+in {
+  options.programs.steam.enable = mkEnableOption "steam";
+
+  config = mkIf cfg.enable {
+    hardware.opengl = { # this fixes the "glXChooseVisual failed" bug, context: https://github.com/NixOS/nixpkgs/issues/47932
+      enable = true;
+      driSupport32Bit = true;
+    };
+
+    # optionally enable 32bit pulseaudio support if pulseaudio is enabled
+    hardware.pulseaudio.support32Bit = config.hardware.pulseaudio.enable;
+
+    hardware.steam-hardware.enable = true;
+
+    environment.systemPackages = [ pkgs.steam ];
+  };
+
+  meta.maintainers = with maintainers; [ mkg20001 ];
+}
diff --git a/nixos/modules/programs/tsm-client.nix b/nixos/modules/programs/tsm-client.nix
index eb6f12475286f..7ac4086d5f094 100644
--- a/nixos/modules/programs/tsm-client.nix
+++ b/nixos/modules/programs/tsm-client.nix
@@ -7,7 +7,7 @@ let
   inherit (lib.modules) mkDefault mkIf;
   inherit (lib.options) literalExample mkEnableOption mkOption;
   inherit (lib.strings) concatStringsSep optionalString toLower;
-  inherit (lib.types) addCheck attrsOf lines loaOf nullOr package path port str strMatching submodule;
+  inherit (lib.types) addCheck attrsOf lines nullOr package path port str strMatching submodule;
 
   # Checks if given list of strings contains unique
   # elements when compared without considering case.
@@ -178,7 +178,7 @@ let
       client system-options file "dsm.sys"
     '';
     servers = mkOption {
-      type = loaOf (submodule [ serverOptions ]);
+      type = attrsOf (submodule [ serverOptions ]);
       default = {};
       example.mainTsmServer = {
         server = "tsmserver.company.com";
diff --git a/nixos/modules/programs/xss-lock.nix b/nixos/modules/programs/xss-lock.nix
index a7ad9b89db4db..83ed713864079 100644
--- a/nixos/modules/programs/xss-lock.nix
+++ b/nixos/modules/programs/xss-lock.nix
@@ -34,7 +34,7 @@ in
       partOf = [ "graphical-session.target" ];
       serviceConfig.ExecStart = with lib;
         strings.concatStringsSep " " ([
-            "${pkgs.xss-lock}/bin/xss-lock"
+            "${pkgs.xss-lock}/bin/xss-lock" "--session \${XDG_SESSION_ID}"
           ] ++ (map escapeShellArg cfg.extraOptions) ++ [
             "--"
             cfg.lockerCommand
diff --git a/nixos/modules/programs/zsh/oh-my-zsh.xml b/nixos/modules/programs/zsh/oh-my-zsh.xml
index 568c2de655766..14a7228ad9b02 100644
--- a/nixos/modules/programs/zsh/oh-my-zsh.xml
+++ b/nixos/modules/programs/zsh/oh-my-zsh.xml
@@ -73,7 +73,7 @@
 <programlisting>
 { pkgs, ... }:
 {
-  programs.zsh.ohMyZsh.customPkgs = with pkgs; [
+  programs.zsh.ohMyZsh.customPkgs = [
     pkgs.nix-zsh-completions
     # and even more...
   ];
diff --git a/nixos/modules/rename.nix b/nixos/modules/rename.nix
index 1dc7f85331769..a87db475e012d 100644
--- a/nixos/modules/rename.nix
+++ b/nixos/modules/rename.nix
@@ -17,8 +17,13 @@ with lib;
     (mkAliasOptionModule [ "environment" "checkConfigurationOptions" ] [ "_module" "check" ])
 
     # Completely removed modules
+    (mkRemovedOptionModule [ "fonts" "fontconfig" "penultimate" ] "The corresponding package has removed from nixpkgs.")
+    (mkRemovedOptionModule [ "services" "chronos" ] "The corresponding package was removed from nixpkgs.")
+    (mkRemovedOptionModule [ "services" "deepin" ] "The corresponding packages were removed from nixpkgs.")
     (mkRemovedOptionModule [ "services" "firefox" "syncserver" "user" ] "")
     (mkRemovedOptionModule [ "services" "firefox" "syncserver" "group" ] "")
+    (mkRemovedOptionModule [ "services" "marathon" ] "The corresponding package was removed from nixpkgs.")
+    (mkRemovedOptionModule [ "services" "mesos" ] "The corresponding package was removed from nixpkgs.")
     (mkRemovedOptionModule [ "services" "winstone" ] "The corresponding package was removed from nixpkgs.")
     (mkRemovedOptionModule [ "networking" "vpnc" ] "Use environment.etc.\"vpnc/service.conf\" instead.")
     (mkRemovedOptionModule [ "environment" "blcr" "enable" ] "The BLCR module has been removed")
@@ -28,6 +33,7 @@ with lib;
     (mkRemovedOptionModule [ "services" "osquery" ] "The osquery module has been removed")
     (mkRemovedOptionModule [ "services" "fourStore" ] "The fourStore module has been removed")
     (mkRemovedOptionModule [ "services" "fourStoreEndpoint" ] "The fourStoreEndpoint module has been removed")
+    (mkRemovedOptionModule [ "services" "mathics" ] "The Mathics module has been removed")
     (mkRemovedOptionModule [ "programs" "way-cooler" ] ("way-cooler is abandoned by its author: " +
       "https://way-cooler.org/blog/2020/01/09/way-cooler-post-mortem.html"))
     (mkRemovedOptionModule [ "services" "xserver" "multitouch" ] ''
@@ -39,10 +45,11 @@ with lib;
       The services.xserver.displayManager.auto module has been removed
       because it was only intended for use in internal NixOS tests, and gave the
       false impression of it being a special display manager when it's actually
-      LightDM. Please use the services.xserver.displayManager.lightdm.autoLogin options
+      LightDM. Please use the services.xserver.displayManager.autoLogin options
       instead, or any other display manager in NixOS as they all support auto-login.
     '')
     (mkRemovedOptionModule [ "services" "dnscrypt-proxy" ] "Use services.dnscrypt-proxy2 instead")
+    (mkRemovedOptionModule [ "services" "meguca" ] "Use meguca has been removed from nixpkgs")
     (mkRemovedOptionModule ["hardware" "brightnessctl" ] ''
       The brightnessctl module was removed because newer versions of
       brightnessctl don't require the udev rules anymore (they can use the
@@ -61,6 +68,8 @@ with lib;
       to handle FIDO security tokens, so this isn't necessary anymore.
     '')
 
+    (mkRemovedOptionModule [ "services" "seeks" ] "")
+
     # Do NOT add any option renames here, see top of the file
   ];
 }
diff --git a/nixos/modules/security/acme.nix b/nixos/modules/security/acme.nix
index 776ef07d716c6..8e67d4ff87166 100644
--- a/nixos/modules/security/acme.nix
+++ b/nixos/modules/security/acme.nix
@@ -1,11 +1,314 @@
-{ config, lib, pkgs, ... }:
+{ config, lib, pkgs, options, ... }:
 with lib;
 let
-
   cfg = config.security.acme;
 
+  # Used to calculate timer accuracy for coalescing
+  numCerts = length (builtins.attrNames cfg.certs);
+  _24hSecs = 60 * 60 * 24;
+
+  # There are many services required to make cert renewals work.
+  # They all follow a common structure:
+  #   - They inherit this commonServiceConfig
+  #   - They all run as the acme user
+  #   - They all use BindPath and StateDirectory where possible
+  #     to set up a sort of build environment in /tmp
+  # The Group can vary depending on what the user has specified in
+  # security.acme.certs.<cert>.group on some of the services.
+  commonServiceConfig = {
+      Type = "oneshot";
+      User = "acme";
+      Group = mkDefault "acme";
+      UMask = 0027;
+      StateDirectoryMode = 750;
+      ProtectSystem = "full";
+      PrivateTmp = true;
+
+      WorkingDirectory = "/tmp";
+  };
+
+  # In order to avoid race conditions creating the CA for selfsigned certs,
+  # we have a separate service which will create the necessary files.
+  selfsignCAService = {
+    description = "Generate self-signed certificate authority";
+
+    path = with pkgs; [ minica ];
+
+    unitConfig = {
+      ConditionPathExists = "!/var/lib/acme/.minica/key.pem";
+    };
+
+    serviceConfig = commonServiceConfig // {
+      StateDirectory = "acme/.minica";
+      BindPaths = "/var/lib/acme/.minica:/tmp/ca";
+    };
+
+    # Working directory will be /tmp
+    script = ''
+      minica \
+        --ca-key ca/key.pem \
+        --ca-cert ca/cert.pem \
+        --domains selfsigned.local
+
+      chmod 600 ca/*
+    '';
+  };
+
+  # Previously, all certs were owned by whatever user was configured in
+  # config.security.acme.certs.<cert>.user. Now everything is owned by and
+  # run by the acme user.
+  userMigrationService = {
+    description = "Fix owner and group of all ACME certificates";
+
+    script = with builtins; concatStringsSep "\n" (mapAttrsToList (cert: data: ''
+      for fixpath in /var/lib/acme/${escapeShellArg cert} /var/lib/acme/.lego/${escapeShellArg cert}; do
+        if [ -d "$fixpath" ]; then
+          chmod -R 750 "$fixpath"
+          chown -R acme:${data.group} "$fixpath"
+        fi
+      done
+    '') certConfigs);
+
+    # We don't want this to run every time a renewal happens
+    serviceConfig.RemainAfterExit = true;
+  };
+
+  certToConfig = cert: data: let
+    acmeServer = if data.server != null then data.server else cfg.server;
+    useDns = data.dnsProvider != null;
+    destPath = "/var/lib/acme/${cert}";
+    selfsignedDeps = optionals (cfg.preliminarySelfsigned) [ "acme-selfsigned-${cert}.service" ];
+
+    # Minica and lego have a "feature" which replaces * with _. We need
+    # to make this substitution to reference the output files from both programs.
+    # End users never see this since we rename the certs.
+    keyName = builtins.replaceStrings ["*"] ["_"] data.domain;
+
+    # FIXME when mkChangedOptionModule supports submodules, change to that.
+    # This is a workaround
+    extraDomains = data.extraDomainNames ++ (
+      optionals
+      (data.extraDomains != "_mkMergedOptionModule")
+      (builtins.attrNames data.extraDomains)
+    );
+
+    # Create hashes for cert data directories based on configuration
+    # Flags are separated to avoid collisions
+    hashData = with builtins; ''
+      ${concatStringsSep " " data.extraLegoFlags} -
+      ${concatStringsSep " " data.extraLegoRunFlags} -
+      ${concatStringsSep " " data.extraLegoRenewFlags} -
+      ${toString acmeServer} ${toString data.dnsProvider}
+      ${toString data.ocspMustStaple} ${data.keyType}
+    '';
+    mkHash = with builtins; val: substring 0 20 (hashString "sha256" val);
+    certDir = mkHash hashData;
+    domainHash = mkHash "${concatStringsSep " " extraDomains} ${data.domain}";
+    othersHash = mkHash "${toString acmeServer} ${data.keyType}";
+    accountDir = "/var/lib/acme/.lego/accounts/" + othersHash;
+
+    protocolOpts = if useDns then (
+      [ "--dns" data.dnsProvider ]
+      ++ optionals (!data.dnsPropagationCheck) [ "--dns.disable-cp" ]
+    ) else (
+      [ "--http" "--http.webroot" data.webroot ]
+    );
+
+    commonOpts = [
+      "--accept-tos" # Checking the option is covered by the assertions
+      "--path" "."
+      "-d" data.domain
+      "--email" data.email
+      "--key-type" data.keyType
+    ] ++ protocolOpts
+      ++ optionals data.ocspMustStaple [ "--must-staple" ]
+      ++ optionals (acmeServer != null) [ "--server" acmeServer ]
+      ++ concatMap (name: [ "-d" name ]) extraDomains
+      ++ data.extraLegoFlags;
+
+    runOpts = escapeShellArgs (
+      commonOpts
+      ++ [ "run" ]
+      ++ data.extraLegoRunFlags
+    );
+    renewOpts = escapeShellArgs (
+      commonOpts
+      ++ [ "renew" "--reuse-key" ]
+      ++ data.extraLegoRenewFlags
+    );
+
+  in {
+    inherit accountDir selfsignedDeps;
+
+    webroot = data.webroot;
+    group = data.group;
+
+    renewTimer = {
+      description = "Renew ACME Certificate for ${cert}";
+      wantedBy = [ "timers.target" ];
+      timerConfig = {
+        OnCalendar = cfg.renewInterval;
+        Unit = "acme-${cert}.service";
+        Persistent = "yes";
+
+        # Allow systemd to pick a convenient time within the day
+        # to run the check.
+        # This allows the coalescing of multiple timer jobs.
+        # We divide by the number of certificates so that if you
+        # have many certificates, the renewals are distributed over
+        # the course of the day to avoid rate limits.
+        AccuracySec = "${toString (_24hSecs / numCerts)}s";
+
+        # Skew randomly within the day, per https://letsencrypt.org/docs/integration-guide/.
+        RandomizedDelaySec = "24h";
+      };
+    };
+
+    selfsignService = {
+      description = "Generate self-signed certificate for ${cert}";
+      after = [ "acme-selfsigned-ca.service" "acme-fixperms.service" ];
+      requires = [ "acme-selfsigned-ca.service" "acme-fixperms.service" ];
+
+      path = with pkgs; [ minica ];
+
+      unitConfig = {
+        ConditionPathExists = "!/var/lib/acme/${cert}/key.pem";
+      };
+
+      serviceConfig = commonServiceConfig // {
+        Group = data.group;
+
+        StateDirectory = "acme/${cert}";
+
+        BindPaths = "/var/lib/acme/.minica:/tmp/ca /var/lib/acme/${cert}:/tmp/${keyName}";
+      };
+
+      # Working directory will be /tmp
+      # minica will output to a folder sharing the name of the first domain
+      # in the list, which will be ${data.domain}
+      script = ''
+        minica \
+          --ca-key ca/key.pem \
+          --ca-cert ca/cert.pem \
+          --domains ${escapeShellArg (builtins.concatStringsSep "," ([ data.domain ] ++ extraDomains))}
+
+        # Create files to match directory layout for real certificates
+        cd '${keyName}'
+        cp ../ca/cert.pem chain.pem
+        cat cert.pem chain.pem > fullchain.pem
+        cat key.pem fullchain.pem > full.pem
+
+        chmod 640 *
+
+        # Group might change between runs, re-apply it
+        chown 'acme:${data.group}' *
+      '';
+    };
+
+    renewService = {
+      description = "Renew ACME certificate for ${cert}";
+      after = [ "network.target" "network-online.target" "acme-fixperms.service" ] ++ selfsignedDeps;
+      wants = [ "network-online.target" "acme-fixperms.service" ] ++ selfsignedDeps;
+
+      # https://github.com/NixOS/nixpkgs/pull/81371#issuecomment-605526099
+      wantedBy = optionals (!config.boot.isContainer) [ "multi-user.target" ];
+
+      path = with pkgs; [ lego coreutils diffutils ];
+
+      serviceConfig = commonServiceConfig // {
+        Group = data.group;
+
+        # AccountDir dir will be created by tmpfiles to ensure correct permissions
+        # And to avoid deletion during systemctl clean
+        # acme/.lego/${cert} is listed so that it is deleted during systemctl clean
+        StateDirectory = "acme/${cert} acme/.lego/${cert} acme/.lego/${cert}/${certDir}";
+
+        # Needs to be space separated, but can't use a multiline string because that'll include newlines
+        BindPaths =
+          "${accountDir}:/tmp/accounts " +
+          "/var/lib/acme/${cert}:/tmp/out " +
+          "/var/lib/acme/.lego/${cert}/${certDir}:/tmp/certificates ";
+
+        # Only try loading the credentialsFile if the dns challenge is enabled
+        EnvironmentFile = mkIf useDns data.credentialsFile;
+
+        # Run as root (Prefixed with +)
+        ExecStartPost = "+" + (pkgs.writeShellScript "acme-postrun" ''
+          cd /var/lib/acme/${escapeShellArg cert}
+          if [ -e renewed ]; then
+            rm renewed
+            ${data.postRun}
+          fi
+        '');
+      };
+
+      # Working directory will be /tmp
+      script = ''
+        set -euo pipefail
+
+        echo '${domainHash}' > domainhash.txt
+
+        # Check if we can renew
+        if [ -e 'certificates/${keyName}.key' -a -e 'certificates/${keyName}.crt' ]; then
+
+          # When domains are updated, there's no need to do a full
+          # Lego run, but it's likely renew won't work if days is too low.
+          if [ -e certificates/domainhash.txt ] && cmp -s domainhash.txt certificates/domainhash.txt; then
+            lego ${renewOpts} --days ${toString cfg.validMinDays}
+          else
+            # Any number > 90 works, but this one is over 9000 ;-)
+            lego ${renewOpts} --days 9001
+          fi
+
+        # Otherwise do a full run
+        else
+          lego ${runOpts}
+        fi
+
+        mv domainhash.txt certificates/
+        chmod 640 certificates/*
+        chmod -R 700 accounts/*
+
+        # Group might change between runs, re-apply it
+        chown 'acme:${data.group}' certificates/*
+
+        # Copy all certs to the "real" certs directory
+        CERT='certificates/${keyName}.crt'
+        if [ -e "$CERT" ] && ! cmp -s "$CERT" out/fullchain.pem; then
+          touch out/renewed
+          echo Installing new certificate
+          cp -vp 'certificates/${keyName}.crt' out/fullchain.pem
+          cp -vp 'certificates/${keyName}.key' out/key.pem
+          cp -vp 'certificates/${keyName}.issuer.crt' out/chain.pem
+          ln -sf fullchain.pem out/cert.pem
+          cat out/key.pem out/fullchain.pem > out/full.pem
+        fi
+      '';
+    };
+  };
+
+  certConfigs = mapAttrs certToConfig cfg.certs;
+
   certOpts = { name, ... }: {
     options = {
+      # user option has been removed
+      user = mkOption {
+        visible = false;
+        default = "_mkRemovedOptionModule";
+      };
+
+      # allowKeysForGroup option has been removed
+      allowKeysForGroup = mkOption {
+        visible = false;
+        default = "_mkRemovedOptionModule";
+      };
+
+      # extraDomains was replaced with extraDomainNames
+      extraDomains = mkOption {
+        visible = false;
+        default = "_mkMergedOptionModule";
+      };
+
       webroot = mkOption {
         type = types.nullOr types.str;
         default = null;
@@ -23,16 +326,16 @@ let
         type = types.nullOr types.str;
         default = null;
         description = ''
-          ACME Directory Resource URI. Defaults to let's encrypt
+          ACME Directory Resource URI. Defaults to Let's Encrypt's
           production endpoint,
-          https://acme-v02.api.letsencrypt.org/directory, if unset.
+          <link xlink:href="https://acme-v02.api.letsencrypt.org/directory"/>, if unset.
         '';
       };
 
       domain = mkOption {
         type = types.str;
         default = name;
-        description = "Domain to fetch certificate for (defaults to the entry name)";
+        description = "Domain to fetch certificate for (defaults to the entry name).";
       };
 
       email = mkOption {
@@ -41,35 +344,19 @@ let
         description = "Contact email address for the CA to be able to reach you.";
       };
 
-      user = mkOption {
-        type = types.str;
-        default = "root";
-        description = "User running the ACME client.";
-      };
-
       group = mkOption {
         type = types.str;
-        default = "root";
+        default = "acme";
         description = "Group running the ACME client.";
       };
 
-      allowKeysForGroup = mkOption {
-        type = types.bool;
-        default = false;
-        description = ''
-          Give read permissions to the specified group
-          (<option>security.acme.cert.&lt;name&gt;.group</option>) to read SSL private certificates.
-        '';
-      };
-
       postRun = mkOption {
         type = types.lines;
         default = "";
-        example = "systemctl reload nginx.service";
+        example = "cp full.pem backup.pem";
         description = ''
-          Commands to run after new certificates go live. Typically
-          the web server and other servers using certificates need to
-          be reloaded.
+          Commands to run after new certificates go live. Note that
+          these commands run as the root user.
 
           Executed in the same directory with the new certificate.
         '';
@@ -82,18 +369,17 @@ let
         description = "Directory where certificate and other state is stored.";
       };
 
-      extraDomains = mkOption {
-        type = types.attrsOf (types.nullOr types.str);
-        default = {};
+      extraDomainNames = mkOption {
+        type = types.listOf types.str;
+        default = [];
         example = literalExample ''
-          {
-            "example.org" = null;
-            "mydomain.org" = null;
-          }
+          [
+            "example.org"
+            "mydomain.org"
+          ]
         '';
         description = ''
           A list of extra domain names, which are included in the one certificate to be issued.
-          Setting a distinct server root is deprecated and not functional in 20.03+
         '';
       };
 
@@ -103,7 +389,7 @@ let
         description = ''
           Key type to use for private keys.
           For an up to date list of supported values check the --key-type option
-          at https://go-acme.github.io/lego/usage/cli/#usage.
+          at <link xlink:href="https://go-acme.github.io/lego/usage/cli/#usage"/>.
         '';
       };
 
@@ -113,7 +399,7 @@ let
         example = "route53";
         description = ''
           DNS Challenge provider. For a list of supported providers, see the "code"
-          field of the DNS providers listed at https://go-acme.github.io/lego/dns/.
+          field of the DNS providers listed at <link xlink:href="https://go-acme.github.io/lego/dns/"/>.
         '';
       };
 
@@ -123,7 +409,7 @@ let
           Path to an EnvironmentFile for the cert's service containing any required and
           optional environment variables for your selected dnsProvider.
           To find out what values you need to set, consult the documentation at
-          https://go-acme.github.io/lego/dns/ for the corresponding dnsProvider.
+          <link xlink:href="https://go-acme.github.io/lego/dns/"/> for the corresponding dnsProvider.
         '';
         example = "/var/src/secrets/example.org-route53-api-token";
       };
@@ -150,6 +436,14 @@ let
         '';
       };
 
+      extraLegoFlags = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        description = ''
+          Additional global flags to pass to all lego commands.
+        '';
+      };
+
       extraLegoRenewFlags = mkOption {
         type = types.listOf types.str;
         default = [];
@@ -157,27 +451,19 @@ let
           Additional flags to pass to lego renew.
         '';
       };
+
+      extraLegoRunFlags = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        description = ''
+          Additional flags to pass to lego run.
+        '';
+      };
     };
   };
 
-in
+in {
 
-{
-
-  ###### interface
-  imports = [
-    (mkRemovedOptionModule [ "security" "acme" "production" ] ''
-      Use security.acme.server to define your staging ACME server URL instead.
-
-      To use the let's encrypt staging server, use security.acme.server =
-      "https://acme-staging-v02.api.letsencrypt.org/directory".
-    ''
-    )
-    (mkRemovedOptionModule [ "security" "acme" "directory"] "ACME Directory is now hardcoded to /var/lib/acme and its permisisons are managed by systemd. See https://github.com/NixOS/nixpkgs/issues/53852 for more info.")
-    (mkRemovedOptionModule [ "security" "acme" "preDelay"] "This option has been removed. If you want to make sure that something executes before certificates are provisioned, add a RequiredBy=acme-\${cert}.service to the service you want to execute before the cert renewal")
-    (mkRemovedOptionModule [ "security" "acme" "activationDelay"] "This option has been removed. If you want to make sure that something executes before certificates are provisioned, add a RequiredBy=acme-\${cert}.service to the service you want to execute before the cert renewal")
-    (mkChangedOptionModule [ "security" "acme" "validMin"] [ "security" "acme" "validMinDays"] (config: config.security.acme.validMin / (24 * 3600)))
-  ];
   options = {
     security.acme = {
 
@@ -207,9 +493,9 @@ in
         type = types.nullOr types.str;
         default = null;
         description = ''
-          ACME Directory Resource URI. Defaults to let's encrypt
+          ACME Directory Resource URI. Defaults to Let's Encrypt's
           production endpoint,
-          <literal>https://acme-v02.api.letsencrypt.org/directory</literal>, if unset.
+          <link xlink:href="https://acme-v02.api.letsencrypt.org/directory"/>, if unset.
         '';
       };
 
@@ -230,8 +516,8 @@ in
         type = types.bool;
         default = false;
         description = ''
-          Accept the CA's terms of service. The default provier is Let's Encrypt,
-          you can find their ToS at https://letsencrypt.org/repository/
+          Accept the CA's terms of service. The default provider is Let's Encrypt,
+          you can find their ToS at <link xlink:href="https://letsencrypt.org/repository/"/>.
         '';
       };
 
@@ -250,7 +536,7 @@ in
             "example.com" = {
               webroot = "/var/www/challenges/";
               email = "foo@example.com";
-              extraDomains = { "www.example.com" = null; "foo.example.com" = null; };
+              extraDomainNames = [ "www.example.com" "foo.example.com" ];
             };
             "bar.example.com" = {
               webroot = "/var/www/challenges/";
@@ -262,25 +548,40 @@ in
     };
   };
 
-  ###### implementation
+  imports = [
+    (mkRemovedOptionModule [ "security" "acme" "production" ] ''
+      Use security.acme.server to define your staging ACME server URL instead.
+
+      To use the let's encrypt staging server, use security.acme.server =
+      "https://acme-staging-v02.api.letsencrypt.org/directory".
+    ''
+    )
+    (mkRemovedOptionModule [ "security" "acme" "directory" ] "ACME Directory is now hardcoded to /var/lib/acme and its permisisons are managed by systemd. See https://github.com/NixOS/nixpkgs/issues/53852 for more info.")
+    (mkRemovedOptionModule [ "security" "acme" "preDelay" ] "This option has been removed. If you want to make sure that something executes before certificates are provisioned, add a RequiredBy=acme-\${cert}.service to the service you want to execute before the cert renewal")
+    (mkRemovedOptionModule [ "security" "acme" "activationDelay" ] "This option has been removed. If you want to make sure that something executes before certificates are provisioned, add a RequiredBy=acme-\${cert}.service to the service you want to execute before the cert renewal")
+    (mkChangedOptionModule [ "security" "acme" "validMin" ] [ "security" "acme" "validMinDays" ] (config: config.security.acme.validMin / (24 * 3600)))
+  ];
+
   config = mkMerge [
     (mkIf (cfg.certs != { }) {
 
+      # FIXME Most of these custom warnings and filters for security.acme.certs.* are required
+      # because using mkRemovedOptionModule/mkChangedOptionModule with attrsets isn't possible.
+      warnings = filter (w: w != "") (mapAttrsToList (cert: data: if data.extraDomains != "_mkMergedOptionModule" then ''
+        The option definition `security.acme.certs.${cert}.extraDomains` has changed
+        to `security.acme.certs.${cert}.extraDomainNames` and is now a list of strings.
+        Setting a custom webroot for extra domains is not possible, instead use separate certs.
+      '' else "") cfg.certs);
+
       assertions = let
-        certs = (mapAttrsToList (k: v: v) cfg.certs);
+        certs = attrValues cfg.certs;
       in [
         {
-          assertion = all (certOpts: certOpts.dnsProvider == null || certOpts.webroot == null) certs;
-          message = ''
-            Options `security.acme.certs.<name>.dnsProvider` and
-            `security.acme.certs.<name>.webroot` are mutually exclusive.
-          '';
-        }
-        {
           assertion = cfg.email != null || all (certOpts: certOpts.email != null) certs;
           message = ''
             You must define `security.acme.certs.<name>.email` or
-            `security.acme.email` to register with the CA.
+            `security.acme.email` to register with the CA. Note that using
+            many different addresses for certs may trigger account rate limits.
           '';
         }
         {
@@ -291,170 +592,78 @@ in
             to `true`. For Let's Encrypt's ToS see https://letsencrypt.org/repository/
           '';
         }
-      ];
-
-      systemd.services = let
-          services = concatLists servicesLists;
-          servicesLists = mapAttrsToList certToServices cfg.certs;
-          certToServices = cert: data:
-              let
-                # StateDirectory must be relative, and will be created under /var/lib by systemd
-                lpath = "acme/${cert}";
-                apath = "/var/lib/${lpath}";
-                spath = "/var/lib/acme/.lego/${cert}";
-                fileMode = if data.allowKeysForGroup then "640" else "600";
-                globalOpts = [ "-d" data.domain "--email" data.email "--path" "." "--key-type" data.keyType ]
-                          ++ optionals (cfg.acceptTerms) [ "--accept-tos" ]
-                          ++ optionals (data.dnsProvider != null && !data.dnsPropagationCheck) [ "--dns.disable-cp" ]
-                          ++ concatLists (mapAttrsToList (name: root: [ "-d" name ]) data.extraDomains)
-                          ++ (if data.dnsProvider != null then [ "--dns" data.dnsProvider ] else [ "--http" "--http.webroot" data.webroot ])
-                          ++ optionals (cfg.server != null || data.server != null) ["--server" (if data.server == null then cfg.server else data.server)];
-                certOpts = optionals data.ocspMustStaple [ "--must-staple" ];
-                runOpts = escapeShellArgs (globalOpts ++ [ "run" ] ++ certOpts);
-                renewOpts = escapeShellArgs (globalOpts ++
-                  [ "renew" "--days" (toString cfg.validMinDays) ] ++
-                  certOpts ++ data.extraLegoRenewFlags);
-                acmeService = {
-                  description = "Renew ACME Certificate for ${cert}";
-                  after = [ "network.target" "network-online.target" ];
-                  wants = [ "network-online.target" ];
-                  wantedBy = mkIf (!config.boot.isContainer) [ "multi-user.target" ];
-                  serviceConfig = {
-                    Type = "oneshot";
-                    User = data.user;
-                    Group = data.group;
-                    PrivateTmp = true;
-                    StateDirectory = "acme/.lego/${cert} acme/.lego/accounts ${lpath}";
-                    StateDirectoryMode = if data.allowKeysForGroup then "750" else "700";
-                    WorkingDirectory = spath;
-                    # Only try loading the credentialsFile if the dns challenge is enabled
-                    EnvironmentFile = if data.dnsProvider != null then data.credentialsFile else null;
-                    ExecStart = pkgs.writeScript "acme-start" ''
-                      #!${pkgs.runtimeShell} -e
-                      test -L ${spath}/accounts -o -d ${spath}/accounts || ln -s ../accounts ${spath}/accounts
-                      ${pkgs.lego}/bin/lego ${renewOpts} || ${pkgs.lego}/bin/lego ${runOpts}
-                    '';
-                    ExecStartPost =
-                      let
-                        keyName = builtins.replaceStrings ["*"] ["_"] data.domain;
-                        script = pkgs.writeScript "acme-post-start" ''
-                          #!${pkgs.runtimeShell} -e
-                          cd ${apath}
-
-                          # Test that existing cert is older than new cert
-                          KEY=${spath}/certificates/${keyName}.key
-                          KEY_CHANGED=no
-                          if [ -e $KEY -a $KEY -nt key.pem ]; then
-                            KEY_CHANGED=yes
-                            cp -p ${spath}/certificates/${keyName}.key key.pem
-                            cp -p ${spath}/certificates/${keyName}.crt fullchain.pem
-                            cp -p ${spath}/certificates/${keyName}.issuer.crt chain.pem
-                            ln -sf fullchain.pem cert.pem
-                            cat key.pem fullchain.pem > full.pem
-                          fi
-
-                          chmod ${fileMode} *.pem
-                          chown '${data.user}:${data.group}' *.pem
-
-                          if [ "$KEY_CHANGED" = "yes" ]; then
-                            : # noop in case postRun is empty
-                            ${data.postRun}
-                          fi
-                        '';
-                      in
-                        "+${script}";
-                  };
-
-                };
-                selfsignedService = {
-                  description = "Create preliminary self-signed certificate for ${cert}";
-                  path = [ pkgs.openssl ];
-                  script =
-                    ''
-                      workdir="$(mktemp -d)"
-
-                      # Create CA
-                      openssl genrsa -des3 -passout pass:xxxx -out $workdir/ca.pass.key 2048
-                      openssl rsa -passin pass:xxxx -in $workdir/ca.pass.key -out $workdir/ca.key
-                      openssl req -new -key $workdir/ca.key -out $workdir/ca.csr \
-                        -subj "/C=UK/ST=Warwickshire/L=Leamington/O=OrgName/OU=Security Department/CN=example.com"
-                      openssl x509 -req -days 1 -in $workdir/ca.csr -signkey $workdir/ca.key -out $workdir/ca.crt
-
-                      # Create key
-                      openssl genrsa -des3 -passout pass:xxxx -out $workdir/server.pass.key 2048
-                      openssl rsa -passin pass:xxxx -in $workdir/server.pass.key -out $workdir/server.key
-                      openssl req -new -key $workdir/server.key -out $workdir/server.csr \
-                        -subj "/C=UK/ST=Warwickshire/L=Leamington/O=OrgName/OU=IT Department/CN=example.com"
-                      openssl x509 -req -days 1 -in $workdir/server.csr -CA $workdir/ca.crt \
-                        -CAkey $workdir/ca.key -CAserial $workdir/ca.srl -CAcreateserial \
-                        -out $workdir/server.crt
-
-                      # Copy key to destination
-                      cp $workdir/server.key ${apath}/key.pem
-
-                      # Create fullchain.pem (same format as "simp_le ... -f fullchain.pem" creates)
-                      cat $workdir/{server.crt,ca.crt} > "${apath}/fullchain.pem"
-
-                      # Create full.pem for e.g. lighttpd
-                      cat $workdir/{server.key,server.crt,ca.crt} > "${apath}/full.pem"
-
-                      # Give key acme permissions
-                      chown '${data.user}:${data.group}' "${apath}/"{key,fullchain,full}.pem
-                      chmod ${fileMode} "${apath}/"{key,fullchain,full}.pem
-                    '';
-                  serviceConfig = {
-                    Type = "oneshot";
-                    PrivateTmp = true;
-                    StateDirectory = lpath;
-                    User = data.user;
-                    Group = data.group;
-                  };
-                  unitConfig = {
-                    # Do not create self-signed key when key already exists
-                    ConditionPathExists = "!${apath}/key.pem";
-                  };
-                };
-              in (
-                [ { name = "acme-${cert}"; value = acmeService; } ]
-                ++ optional cfg.preliminarySelfsigned { name = "acme-selfsigned-${cert}"; value = selfsignedService; }
-              );
-          servicesAttr = listToAttrs services;
-        in
-          servicesAttr;
-
-      systemd.tmpfiles.rules =
-        map (data: "d ${data.webroot}/.well-known/acme-challenge - ${data.user} ${data.group}") (filter (data: data.webroot != null) (attrValues cfg.certs));
-
-      systemd.timers = let
-        # Allow systemd to pick a convenient time within the day
-        # to run the check.
-        # This allows the coalescing of multiple timer jobs.
-        # We divide by the number of certificates so that if you
-        # have many certificates, the renewals are distributed over
-        # the course of the day to avoid rate limits.
-        numCerts = length (attrNames cfg.certs);
-        _24hSecs = 60 * 60 * 24;
-        AccuracySec = "${toString (_24hSecs / numCerts)}s";
-      in flip mapAttrs' cfg.certs (cert: data: nameValuePair
-        ("acme-${cert}")
-        ({
-          description = "Renew ACME Certificate for ${cert}";
-          wantedBy = [ "timers.target" ];
-          timerConfig = {
-            OnCalendar = cfg.renewInterval;
-            Unit = "acme-${cert}.service";
-            Persistent = "yes";
-            inherit AccuracySec;
-            # Skew randomly within the day, per https://letsencrypt.org/docs/integration-guide/.
-            RandomizedDelaySec = "24h";
-          };
-        })
-      );
-
-      systemd.targets.acme-selfsigned-certificates = mkIf cfg.preliminarySelfsigned {};
-      systemd.targets.acme-certificates = {};
-    })
+      ] ++ (builtins.concatLists (mapAttrsToList (cert: data: [
+        {
+          assertion = data.user == "_mkRemovedOptionModule";
+          message = ''
+            The option definition `security.acme.certs.${cert}.user' no longer has any effect; Please remove it.
+            Certificate user is now hard coded to the "acme" user. If you would
+            like another user to have access, consider adding them to the
+            "acme" group or changing security.acme.certs.${cert}.group.
+          '';
+        }
+        {
+          assertion = data.allowKeysForGroup == "_mkRemovedOptionModule";
+          message = ''
+            The option definition `security.acme.certs.${cert}.allowKeysForGroup' no longer has any effect; Please remove it.
+            All certs are readable by the configured group. If this is undesired,
+            consider changing security.acme.certs.${cert}.group to an unused group.
+          '';
+        }
+        # * in the cert value breaks building of systemd services, and makes
+        # referencing them as a user quite weird too. Best practice is to use
+        # the domain option.
+        {
+          assertion = ! hasInfix "*" cert;
+          message = ''
+            The cert option path `security.acme.certs.${cert}.dnsProvider`
+            cannot contain a * character.
+            Instead, set `security.acme.certs.${cert}.domain = "${cert}";`
+            and remove the wildcard from the path.
+          '';
+        }
+        {
+          assertion = data.dnsProvider == null || data.webroot == null;
+          message = ''
+            Options `security.acme.certs.${cert}.dnsProvider` and
+            `security.acme.certs.${cert}.webroot` are mutually exclusive.
+          '';
+        }
+      ]) cfg.certs));
+
+      users.users.acme = {
+        home = "/var/lib/acme";
+        group = "acme";
+        isSystemUser = true;
+      };
 
+      users.groups.acme = {};
+
+      systemd.services = {
+        "acme-fixperms" = userMigrationService;
+      } // (mapAttrs' (cert: conf: nameValuePair "acme-${cert}" conf.renewService) certConfigs)
+        // (optionalAttrs (cfg.preliminarySelfsigned) ({
+        "acme-selfsigned-ca" = selfsignCAService;
+      } // (mapAttrs' (cert: conf: nameValuePair "acme-selfsigned-${cert}" conf.selfsignService) certConfigs)));
+
+      systemd.timers = mapAttrs' (cert: conf: nameValuePair "acme-${cert}" conf.renewTimer) certConfigs;
+
+      # .lego and .lego/accounts specified to fix any incorrect permissions
+      systemd.tmpfiles.rules = [
+        "d /var/lib/acme/.lego - acme acme"
+        "d /var/lib/acme/.lego/accounts - acme acme"
+      ] ++ (unique (concatMap (conf: [
+          "d ${conf.accountDir} - acme acme"
+        ] ++ (optional (conf.webroot != null) "d ${conf.webroot}/.well-known/acme-challenge - acme ${conf.group}")
+      ) (attrValues certConfigs)));
+
+      # Create some targets which can be depended on to be "active" after cert renewals
+      systemd.targets = mapAttrs' (cert: conf: nameValuePair "acme-finished-${cert}" {
+        wantedBy = [ "default.target" ];
+        requires = [ "acme-${cert}.service" ] ++ conf.selfsignedDeps;
+        after = [ "acme-${cert}.service" ] ++ conf.selfsignedDeps;
+      }) certConfigs;
+    })
   ];
 
   meta = {
diff --git a/nixos/modules/security/acme.xml b/nixos/modules/security/acme.xml
index f802faee97490..17e94bc12fb21 100644
--- a/nixos/modules/security/acme.xml
+++ b/nixos/modules/security/acme.xml
@@ -72,7 +72,7 @@ services.nginx = {
     "foo.example.com" = {
       <link linkend="opt-services.nginx.virtualHosts._name_.forceSSL">forceSSL</link> = true;
       <link linkend="opt-services.nginx.virtualHosts._name_.enableACME">enableACME</link> = true;
-      # All serverAliases will be added as <link linkend="opt-security.acme.certs._name_.extraDomains">extra domains</link> on the certificate.
+      # All serverAliases will be added as <link linkend="opt-security.acme.certs._name_.extraDomainNames">extra domain names</link> on the certificate.
       <link linkend="opt-services.nginx.virtualHosts._name_.serverAliases">serverAliases</link> = [ "bar.example.com" ];
       locations."/" = {
         <link linkend="opt-services.nginx.virtualHosts._name_.locations._name_.root">root</link> = "/var/www";
@@ -80,8 +80,8 @@ services.nginx = {
     };
 
     # We can also add a different vhost and reuse the same certificate
-    # but we have to append extraDomains manually.
-    <link linkend="opt-security.acme.certs._name_.extraDomains">security.acme.certs."foo.example.com".extraDomains."baz.example.com"</link> = null;
+    # but we have to append extraDomainNames manually.
+    <link linkend="opt-security.acme.certs._name_.extraDomainNames">security.acme.certs."foo.example.com".extraDomainNames</link> = [ "baz.example.com" ];
     "baz.example.com" = {
       <link linkend="opt-services.nginx.virtualHosts._name_.forceSSL">forceSSL</link> = true;
       <link linkend="opt-services.nginx.virtualHosts._name_.useACMEHost">useACMEHost</link> = "foo.example.com";
@@ -165,7 +165,7 @@ services.httpd = {
   # Since we have a wildcard vhost to handle port 80,
   # we can generate certs for anything!
   # Just make sure your DNS resolves them.
-  <link linkend="opt-security.acme.certs._name_.extraDomains">extraDomains</link> = [ "mail.example.com" ];
+  <link linkend="opt-security.acme.certs._name_.extraDomainNames">extraDomainNames</link> = [ "mail.example.com" ];
 };
 </programlisting>
 
@@ -251,4 +251,16 @@ chmod 400 /var/lib/secrets/certs.secret
    journalctl -fu acme-example.com.service</literal> and watching its log output.
   </para>
  </section>
+ <section xml:id="module-security-acme-regenerate">
+  <title>Regenerating certificates</title>
+
+  <para>
+   Should you need to regenerate a particular certificate in a hurry, such
+   as when a vulnerability is found in Let's Encrypt, there is now a convenient
+   mechanism for doing so. Running <literal>systemctl clean acme-example.com.service</literal>
+   will remove all certificate files for the given domain, allowing you to then
+   <literal>systemctl start acme-example.com.service</literal> to generate fresh
+   ones.
+  </para>
+ </section>
 </chapter>
diff --git a/nixos/modules/security/apparmor.nix b/nixos/modules/security/apparmor.nix
index cfc65b347bc69..2ee10454fd26b 100644
--- a/nixos/modules/security/apparmor.nix
+++ b/nixos/modules/security/apparmor.nix
@@ -23,11 +23,17 @@ in
          default = [];
          description = "List of packages to be added to apparmor's include path";
        };
+       parserConfig = mkOption {
+         type = types.str;
+         default = "";
+         description = "AppArmor parser configuration file content";
+       };
      };
    };
 
    config = mkIf cfg.enable {
      environment.systemPackages = [ pkgs.apparmor-utils ];
+     environment.etc."apparmor/parser.conf".text = cfg.parserConfig;
 
      boot.kernelParams = [ "apparmor=1" "security=apparmor" ];
 
diff --git a/nixos/modules/security/duosec.nix b/nixos/modules/security/duosec.nix
index 71428b82f5dac..c47be80b9dc3c 100644
--- a/nixos/modules/security/duosec.nix
+++ b/nixos/modules/security/duosec.nix
@@ -51,7 +51,7 @@ in
       };
 
       secretKeyFile = mkOption {
-        type = types.path;
+        type = types.nullOr types.path;
         default = null;
         description = ''
           A file containing your secret key. The security of your Duo application is tied to the security of your secret key.
diff --git a/nixos/modules/security/misc.nix b/nixos/modules/security/misc.nix
index 16e3bfb14199b..d51dbbb77f718 100644
--- a/nixos/modules/security/misc.nix
+++ b/nixos/modules/security/misc.nix
@@ -27,6 +27,16 @@ with lib;
       '';
     };
 
+    security.unprivilegedUsernsClone = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        When disabled, unprivileged users will not be able to create new namespaces.
+        By default unprivileged user namespaces are disabled.
+        This option only works in a hardened profile.
+      '';
+    };
+
     security.protectKernelImage = mkOption {
       type = types.bool;
       default = false;
@@ -115,6 +125,10 @@ with lib;
       ];
     })
 
+    (mkIf config.security.unprivilegedUsernsClone {
+      boot.kernel.sysctl."kernel.unprivileged_userns_clone" = mkDefault true;
+    })
+
     (mkIf config.security.protectKernelImage {
       # Disable hibernation (allows replacing the running kernel)
       boot.kernelParams = [ "nohibernate" ];
diff --git a/nixos/modules/security/pam.nix b/nixos/modules/security/pam.nix
index 688344852aeb2..4141a17c50725 100644
--- a/nixos/modules/security/pam.nix
+++ b/nixos/modules/security/pam.nix
@@ -36,6 +36,17 @@ let
         '';
       };
 
+      p11Auth = mkOption {
+        default = config.security.pam.p11.enable;
+        type = types.bool;
+        description = ''
+          If set, keys listed in
+          <filename>~/.ssh/authorized_keys</filename> and
+          <filename>~/.eid/authorized_certificates</filename>
+          can be used to log in with the associated PKCS#11 tokens.
+        '';
+      };
+
       u2fAuth = mkOption {
         default = config.security.pam.u2f.enable;
         type = types.bool;
@@ -352,6 +363,8 @@ let
               "auth sufficient ${pkgs.pam_ssh_agent_auth}/libexec/pam_ssh_agent_auth.so file=~/.ssh/authorized_keys:~/.ssh/authorized_keys2:/etc/ssh/authorized_keys.d/%u"}
           ${optionalString cfg.fprintAuth
               "auth sufficient ${pkgs.fprintd}/lib/security/pam_fprintd.so"}
+          ${let p11 = config.security.pam.p11; in optionalString cfg.p11Auth
+              "auth ${p11.control} ${pkgs.pam_p11}/lib/security/pam_p11.so ${pkgs.opensc}/lib/opensc-pkcs11.so"}
           ${let u2f = config.security.pam.u2f; in optionalString cfg.u2fAuth
               "auth ${u2f.control} ${pkgs.pam_u2f}/lib/security/pam_u2f.so ${optionalString u2f.debug "debug"} ${optionalString (u2f.authFile != null) "authfile=${u2f.authFile}"} ${optionalString u2f.interactive "interactive"} ${optionalString u2f.cue "cue"}"}
           ${optionalString cfg.usbAuth
@@ -381,7 +394,7 @@ let
                 "auth optional ${pkgs.pam_mount}/lib/security/pam_mount.so"}
               ${optionalString cfg.enableKwallet
                 ("auth optional ${pkgs.plasma5.kwallet-pam}/lib/security/pam_kwallet5.so" +
-                 " kwalletd=${pkgs.libsForQt5.kwallet.bin}/bin/kwalletd5")}
+                 " kwalletd=${pkgs.kdeFrameworks.kwallet.bin}/bin/kwalletd5")}
               ${optionalString cfg.enableGnomeKeyring
                 "auth optional ${pkgs.gnome3.gnome-keyring}/lib/security/pam_gnome_keyring.so"}
               ${optionalString cfg.googleAuthenticator.enable
@@ -458,7 +471,7 @@ let
               "session optional ${pkgs.apparmor-pam}/lib/security/pam_apparmor.so order=user,group,default debug"}
           ${optionalString (cfg.enableKwallet)
               ("session optional ${pkgs.plasma5.kwallet-pam}/lib/security/pam_kwallet5.so" +
-               " kwalletd=${pkgs.libsForQt5.kwallet.bin}/bin/kwalletd5")}
+               " kwalletd=${pkgs.kdeFrameworks.kwallet.bin}/bin/kwalletd5")}
           ${optionalString (cfg.enableGnomeKeyring)
               "session optional ${pkgs.gnome3.gnome-keyring}/lib/security/pam_gnome_keyring.so auto_start"}
           ${optionalString (config.virtualisation.lxc.lxcfs.enable)
@@ -531,7 +544,7 @@ in
 
     security.pam.services = mkOption {
       default = [];
-      type = with types; loaOf (submodule pamOpts);
+      type = with types; attrsOf (submodule pamOpts);
       description =
         ''
           This option defines the PAM services.  A service typically
@@ -566,6 +579,39 @@ in
 
     security.pam.enableOTPW = mkEnableOption "the OTPW (one-time password) PAM module";
 
+    security.pam.p11 = {
+      enable = mkOption {
+        default = false;
+        type = types.bool;
+        description = ''
+          Enables P11 PAM (<literal>pam_p11</literal>) module.
+
+          If set, users can log in with SSH keys and PKCS#11 tokens.
+
+          More information can be found <link
+          xlink:href="https://github.com/OpenSC/pam_p11">here</link>.
+        '';
+      };
+
+      control = mkOption {
+        default = "sufficient";
+        type = types.enum [ "required" "requisite" "sufficient" "optional" ];
+        description = ''
+          This option sets pam "control".
+          If you want to have multi factor authentication, use "required".
+          If you want to use the PKCS#11 device instead of the regular password,
+          use "sufficient".
+
+          Read
+          <citerefentry>
+            <refentrytitle>pam.conf</refentrytitle>
+            <manvolnum>5</manvolnum>
+          </citerefentry>
+          for better understanding of this option.
+        '';
+      };
+    };
+
     security.pam.u2f = {
       enable = mkOption {
         default = false;
@@ -747,6 +793,7 @@ in
       ++ optionals config.krb5.enable [pam_krb5 pam_ccreds]
       ++ optionals config.security.pam.enableOTPW [ pkgs.otpw ]
       ++ optionals config.security.pam.oath.enable [ pkgs.oathToolkit ]
+      ++ optionals config.security.pam.p11.enable [ pkgs.pam_p11 ]
       ++ optionals config.security.pam.u2f.enable [ pkgs.pam_u2f ];
 
     boot.supportedFilesystems = optionals config.security.pam.enableEcryptfs [ "ecryptfs" ];
diff --git a/nixos/modules/security/rngd.nix b/nixos/modules/security/rngd.nix
index cffa1a5849f9d..cb885c4762d06 100644
--- a/nixos/modules/security/rngd.nix
+++ b/nixos/modules/security/rngd.nix
@@ -10,11 +10,10 @@ in
     security.rngd = {
       enable = mkOption {
         type = types.bool;
-        default = true;
+        default = false;
         description = ''
-          Whether to enable the rng daemon, which adds entropy from
-          hardware sources of randomness to the kernel entropy pool when
-          available.
+          Whether to enable the rng daemon.  Devices that the kernel recognises
+          as entropy sources are handled automatically by krngd.
         '';
       };
       debug = mkOption {
@@ -26,12 +25,6 @@ in
   };
 
   config = mkIf cfg.enable {
-    services.udev.extraRules = ''
-      KERNEL=="random", TAG+="systemd"
-      SUBSYSTEM=="cpu", ENV{MODALIAS}=="cpu:type:x86,*feature:*009E*", TAG+="systemd", ENV{SYSTEMD_WANTS}+="rngd.service"
-      KERNEL=="hw_random", TAG+="systemd", ENV{SYSTEMD_WANTS}+="rngd.service"
-    '';
-
     systemd.services.rngd = {
       bindsTo = [ "dev-random.device" ];
 
diff --git a/nixos/modules/security/systemd-confinement.nix b/nixos/modules/security/systemd-confinement.nix
index 0a400f1d535ba..2927d424a8a2e 100644
--- a/nixos/modules/security/systemd-confinement.nix
+++ b/nixos/modules/security/systemd-confinement.nix
@@ -135,7 +135,7 @@ in {
           ];
           execPkgs = lib.concatMap (opt: let
             isSet = config.serviceConfig ? ${opt};
-          in lib.optional isSet config.serviceConfig.${opt}) execOpts;
+          in lib.flatten (lib.optional isSet config.serviceConfig.${opt})) execOpts;
           unitAttrs = toplevelConfig.systemd.units."${name}.service";
           allPkgs = lib.singleton (builtins.toJSON unitAttrs);
           unitPkgs = if fullUnit then allPkgs else execPkgs;
diff --git a/nixos/modules/security/tpm2.nix b/nixos/modules/security/tpm2.nix
index 13804fb82cbaa..27f9b58c9755a 100644
--- a/nixos/modules/security/tpm2.nix
+++ b/nixos/modules/security/tpm2.nix
@@ -170,7 +170,6 @@ in {
           Restart = "always";
           RestartSec = 30;
           BusName = "com.intel.tss2.Tabrmd";
-          StandardOutput = "syslog";
           ExecStart = "${cfg.abrmd.package}/bin/tpm2-abrmd";
           User = "tss";
           Group = "nogroup";
diff --git a/nixos/modules/security/wrappers/default.nix b/nixos/modules/security/wrappers/default.nix
index a0fadb018ecaa..2def74f85353b 100644
--- a/nixos/modules/security/wrappers/default.nix
+++ b/nixos/modules/security/wrappers/default.nix
@@ -160,8 +160,11 @@ in
   config = {
 
     security.wrappers = {
+      # These are mount related wrappers that require the +s permission.
       fusermount.source = "${pkgs.fuse}/bin/fusermount";
       fusermount3.source = "${pkgs.fuse3}/bin/fusermount3";
+      mount.source = "${lib.getBin pkgs.utillinux}/bin/mount";
+      umount.source = "${lib.getBin pkgs.utillinux}/bin/umount";
     };
 
     boot.specialFileSystems.${parentWrapperDir} = {
diff --git a/nixos/modules/services/audio/icecast.nix b/nixos/modules/services/audio/icecast.nix
index 6a8a0f9975b3b..6ca20a7a10866 100644
--- a/nixos/modules/services/audio/icecast.nix
+++ b/nixos/modules/services/audio/icecast.nix
@@ -23,7 +23,7 @@ let
       <listen-socket>
         <port>${toString cfg.listen.port}</port>
         <bind-address>${cfg.listen.address}</bind-address>
-      </listen-socket>   
+      </listen-socket>
 
       <security>
         <chroot>0</chroot>
@@ -47,7 +47,7 @@ in {
       enable = mkEnableOption "Icecast server";
 
       hostname = mkOption {
-        type = types.str;
+        type = types.nullOr types.str;
         description = "DNS name or IP address that will be used for the stream directory lookups or possibily the playlist generation if a Host header is not provided.";
         default = config.networking.domain;
       };
@@ -70,7 +70,7 @@ in {
         description = "Base directory used for logging.";
         default = "/var/log/icecast";
       };
-      
+
       listen = {
         port = mkOption {
           type = types.int;
diff --git a/nixos/modules/services/audio/mpd.nix b/nixos/modules/services/audio/mpd.nix
index 1d2a982ac5367..ba20b1b98d971 100644
--- a/nixos/modules/services/audio/mpd.nix
+++ b/nixos/modules/services/audio/mpd.nix
@@ -11,6 +11,10 @@ let
   cfg = config.services.mpd;
 
   mpdConf = pkgs.writeText "mpd.conf" ''
+    # This file was automatically generated by NixOS. Edit mpd's configuration
+    # via NixOS' configuration.nix, as this file will be rewritten upon mpd's
+    # restart.
+
     music_directory     "${cfg.musicDirectory}"
     playlist_directory  "${cfg.playlistDirectory}"
     ${lib.optionalString (cfg.dbFile != null) ''
@@ -140,6 +144,18 @@ in {
         '';
       };
 
+      credentialsFile = mkOption {
+        type = types.path;
+        description = ''
+          Path to a file to be merged with the settings during the service startup.
+          Useful to merge a file which is better kept out of the Nix store
+          because it contains sensible data like MPD's password. Example may look like this:
+          <literal>password "myMpdPassword@read,add,control,admin"</literal>
+        '';
+        default = "/dev/null";
+        example = "/var/lib/secrets/mpd.conf";
+      };
+
       fluidsynth = mkOption {
         type = types.bool;
         default = false;
@@ -181,7 +197,12 @@ in {
 
       serviceConfig = {
         User = "${cfg.user}";
-        ExecStart = "${pkgs.mpd}/bin/mpd --no-daemon ${mpdConf}";
+        ExecStart = "${pkgs.mpd}/bin/mpd --no-daemon /etc/mpd.conf";
+        ExecStartPre = pkgs.writeScript "mpd-start-pre" ''
+          #!${pkgs.runtimeShell}
+          set -euo pipefail
+          cat ${mpdConf} ${cfg.credentialsFile} > /etc/mpd.conf
+        '';
         Type = "notify";
         LimitRTPRIO = 50;
         LimitRTTIME = "infinity";
@@ -195,6 +216,14 @@ in {
         Restart = "always";
       };
     };
+    environment.etc."mpd.conf" = {
+      mode = "0640";
+      group = cfg.group;
+      user = cfg.user;
+      # To be modified by the service' ExecStartPre
+      text = ''
+      '';
+    };
 
     users.users = optionalAttrs (cfg.user == name) {
       ${name} = {
diff --git a/nixos/modules/services/audio/roon-server.nix b/nixos/modules/services/audio/roon-server.nix
index 6aed485638ccf..eceb65044c5b7 100644
--- a/nixos/modules/services/audio/roon-server.nix
+++ b/nixos/modules/services/audio/roon-server.nix
@@ -45,14 +45,14 @@ in {
       environment.ROON_DATAROOT = "/var/lib/${name}";
 
       serviceConfig = {
-        ExecStart = "${pkgs.roon-server}/opt/start.sh";
+        ExecStart = "${pkgs.roon-server}/start.sh";
         LimitNOFILE = 8192;
         User = cfg.user;
         Group = cfg.group;
         StateDirectory = name;
       };
     };
-    
+
     networking.firewall = mkIf cfg.openFirewall {
       allowedTCPPortRanges = [
         { from = 9100; to = 9200; }
@@ -60,7 +60,7 @@ in {
       allowedUDPPorts = [ 9003 ];
     };
 
-    
+
     users.groups.${cfg.group} = {};
     users.users.${cfg.user} =
       if cfg.user == "roon-server" then {
diff --git a/nixos/modules/services/audio/snapserver.nix b/nixos/modules/services/audio/snapserver.nix
index b0b9264e81666..f614f0ba3e10c 100644
--- a/nixos/modules/services/audio/snapserver.nix
+++ b/nixos/modules/services/audio/snapserver.nix
@@ -31,27 +31,42 @@ let
     let
       os = val:
         optionalString (val != null) "${val}";
-      os' = prefixx: val:
-        optionalString (val != null) (prefixx + "${val}");
+      os' = prefix: val:
+        optionalString (val != null) (prefix + "${val}");
       flatten = key: value:
         "&${key}=${value}";
     in
-      "-s ${opt.type}://" + os opt.location + "?" + os' "name=" name
-        + concatStrings (mapAttrsToList flatten opt.query);
+      "--stream.stream=\"${opt.type}://" + os opt.location + "?" + os' "name=" name
+        + concatStrings (mapAttrsToList flatten opt.query) + "\"";
 
   optionalNull = val: ret:
     optional (val != null) ret;
 
   optionString = concatStringsSep " " (mapAttrsToList streamToOption cfg.streams
-             ++ ["-p ${toString cfg.port}"]
-             ++ ["--controlPort ${toString cfg.controlPort}"]
-             ++ optionalNull cfg.sampleFormat "--sampleFormat ${cfg.sampleFormat}"
-             ++ optionalNull cfg.codec "-c ${cfg.codec}"
-             ++ optionalNull cfg.streamBuffer "--streamBuffer ${cfg.streamBuffer}"
-             ++ optionalNull cfg.buffer "-b ${cfg.buffer}"
-             ++ optional cfg.sendToMuted "--sendToMuted");
+    # global options
+    ++ [ "--stream.bind_to_address ${cfg.listenAddress}" ]
+    ++ [ "--stream.port ${toString cfg.port}" ]
+    ++ optionalNull cfg.sampleFormat "--stream.sampleformat ${cfg.sampleFormat}"
+    ++ optionalNull cfg.codec "--stream.codec ${cfg.codec}"
+    ++ optionalNull cfg.streamBuffer "--stream.stream_buffer ${cfg.streamBuffer}"
+    ++ optionalNull cfg.buffer "--stream.buffer ${cfg.buffer}"
+    ++ optional cfg.sendToMuted "--stream.send_to_muted"
+    # tcp json rpc
+    ++ [ "--tcp.enabled ${toString cfg.tcp.enable}" ]
+    ++ optionals cfg.tcp.enable [
+      "--tcp.address ${cfg.tcp.listenAddress}"
+      "--tcp.port ${toString cfg.tcp.port}" ]
+     # http json rpc
+    ++ [ "--http.enabled ${toString cfg.http.enable}" ]
+    ++ optionals cfg.http.enable [
+      "--http.address ${cfg.http.listenAddress}"
+      "--http.port ${toString cfg.http.port}"
+    ] ++ optional (cfg.http.docRoot != null) "--http.doc_root \"${toString cfg.http.docRoot}\"");
 
 in {
+  imports = [
+    (mkRenamedOptionModule [ "services" "snapserver" "controlPort"] [ "services" "snapserver" "tcp" "port" ])
+  ];
 
   ###### interface
 
@@ -67,6 +82,15 @@ in {
         '';
       };
 
+      listenAddress = mkOption {
+        type = types.str;
+        default = "::";
+        example = "0.0.0.0";
+        description = ''
+          The address where snapclients can connect.
+        '';
+      };
+
       port = mkOption {
         type = types.port;
         default = 1704;
@@ -75,24 +99,100 @@ in {
         '';
       };
 
-      controlPort = mkOption {
+      openFirewall = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          Whether to automatically open the specified ports in the firewall.
+        '';
+      };
+
+      inherit sampleFormat;
+      inherit codec;
+
+      streamBuffer = mkOption {
+        type = with types; nullOr int;
+        default = null;
+        description = ''
+          Stream read (input) buffer in ms.
+        '';
+        example = 20;
+      };
+
+      buffer = mkOption {
+        type = with types; nullOr int;
+        default = null;
+        description = ''
+          Network buffer in ms.
+        '';
+        example = 1000;
+      };
+
+      sendToMuted = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Send audio to muted clients.
+        '';
+      };
+
+      tcp.enable = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          Whether to enable the JSON-RPC via TCP.
+        '';
+      };
+
+      tcp.listenAddress = mkOption {
+        type = types.str;
+        default = "::";
+        example = "0.0.0.0";
+        description = ''
+          The address where the TCP JSON-RPC listens on.
+        '';
+      };
+
+      tcp.port = mkOption {
         type = types.port;
         default = 1705;
         description = ''
-          The port for control connections (JSON-RPC).
+          The port where the TCP JSON-RPC listens on.
         '';
       };
 
-      openFirewall = mkOption {
+      http.enable = mkOption {
         type = types.bool;
         default = true;
         description = ''
-          Whether to automatically open the specified ports in the firewall.
+          Whether to enable the JSON-RPC via HTTP.
         '';
       };
 
-      inherit sampleFormat;
-      inherit codec;
+      http.listenAddress = mkOption {
+        type = types.str;
+        default = "::";
+        example = "0.0.0.0";
+        description = ''
+          The address where the HTTP JSON-RPC listens on.
+        '';
+      };
+
+      http.port = mkOption {
+        type = types.port;
+        default = 1780;
+        description = ''
+          The port where the HTTP JSON-RPC listens on.
+        '';
+      };
+
+      http.docRoot = mkOption {
+        type = with types; nullOr path;
+        default = null;
+        description = ''
+          Path to serve from the HTTP servers root.
+        '';
+      };
 
       streams = mkOption {
         type = with types; attrsOf (submodule {
@@ -147,34 +247,7 @@ in {
           };
         '';
       };
-
-      streamBuffer = mkOption {
-        type = with types; nullOr int;
-        default = null;
-        description = ''
-          Stream read (input) buffer in ms.
-        '';
-        example = 20;
-      };
-
-      buffer = mkOption {
-        type = with types; nullOr int;
-        default = null;
-        description = ''
-          Network buffer in ms.
-        '';
-        example = 1000;
-      };
-
-      sendToMuted = mkOption {
-        type = types.bool;
-        default = false;
-        description = ''
-          Send audio to muted clients.
-        '';
-      };
     };
-
   };
 
 
@@ -206,7 +279,10 @@ in {
       };
     };
 
-    networking.firewall.allowedTCPPorts = optionals cfg.openFirewall [ cfg.port cfg.controlPort ];
+    networking.firewall.allowedTCPPorts =
+      optionals cfg.openFirewall [ cfg.port ]
+      ++ optional cfg.tcp.enable cfg.tcp.port
+      ++ optional cfg.http.enable cfg.http.port;
   };
 
   meta = {
diff --git a/nixos/modules/services/audio/spotifyd.nix b/nixos/modules/services/audio/spotifyd.nix
index 4b74e75327955..a589153248fe9 100644
--- a/nixos/modules/services/audio/spotifyd.nix
+++ b/nixos/modules/services/audio/spotifyd.nix
@@ -16,7 +16,7 @@ in
         type = types.lines;
         description = ''
           Configuration for Spotifyd. For syntax and directives, see
-          https://github.com/Spotifyd/spotifyd#Configuration.
+          <link xlink:href="https://github.com/Spotifyd/spotifyd#Configuration"/>.
         '';
       };
     };
diff --git a/nixos/modules/services/backup/bacula.nix b/nixos/modules/services/backup/bacula.nix
index cef304734aeee..3d69a69038a3c 100644
--- a/nixos/modules/services/backup/bacula.nix
+++ b/nixos/modules/services/backup/bacula.nix
@@ -18,7 +18,7 @@ let
         Pid Directory = "/run";
         ${fd_cfg.extraClientConfig}
       }
-     
+
       ${concatStringsSep "\n" (mapAttrsToList (name: value: ''
       Director {
         Name = "${name}";
@@ -26,7 +26,7 @@ let
         Monitor = "${value.monitor}";
       }
       '') fd_cfg.director)}
-     
+
       Messages {
         Name = Standard;
         syslog = all, !skipped, !restored
@@ -35,7 +35,7 @@ let
     '';
 
   sd_cfg = config.services.bacula-sd;
-  sd_conf = pkgs.writeText "bacula-sd.conf" 
+  sd_conf = pkgs.writeText "bacula-sd.conf"
     ''
       Storage {
         Name = "${sd_cfg.name}";
@@ -80,7 +80,7 @@ let
     '';
 
   dir_cfg = config.services.bacula-dir;
-  dir_conf = pkgs.writeText "bacula-dir.conf" 
+  dir_conf = pkgs.writeText "bacula-dir.conf"
     ''
     Director {
       Name = "${dir_cfg.name}";
@@ -125,10 +125,10 @@ let
 
           The password is plain text. It is not generated through any special
           process but as noted above, it is better to use random text for
-          security reasons. 
+          security reasons.
         '';
       };
-      
+
       monitor = mkOption {
         default = "no";
         example = "yes";
@@ -140,7 +140,7 @@ let
 
           Please note that if this director is being used by a Monitor, we
           highly recommend to set this directive to yes to avoid serious
-          security problems. 
+          security problems.
         '';
       };
     };
@@ -163,7 +163,7 @@ let
           type of autochanger, what you specify here can vary. This directive
           is optional. See the Using AutochangersAutochangersChapter chapter of
           this manual for more details of using this and the following
-          autochanger directives.         
+          autochanger directives.
           '';
       };
 
@@ -200,7 +200,7 @@ let
           Extra configuration to be passed in Autochanger directive.
         '';
         example = ''
-   
+
         '';
       };
     };
@@ -222,7 +222,7 @@ let
           if you are archiving to disk storage. In this case, you must supply
           the full absolute path to the directory. When specifying a tape
           device, it is preferable that the "non-rewind" variant of the device
-          file name be given. 
+          file name be given.
         '';
       };
 
@@ -290,7 +290,7 @@ in {
           Whether to enable the Bacula File Daemon.
         '';
       };
- 
+
       name = mkOption {
         default = "${config.networking.hostName}-fd";
         description = ''
@@ -300,7 +300,7 @@ in {
           Clients. This directive is required.
         '';
       };
- 
+
       port = mkOption {
         default = 9102;
         type = types.int;
@@ -310,7 +310,7 @@ in {
           the Client resource of the Director's configuration file.
         '';
       };
- 
+
       director = mkOption {
         default = {};
         description = ''
@@ -349,14 +349,14 @@ in {
           Whether to enable Bacula Storage Daemon.
         '';
       };
- 
+
       name = mkOption {
         default = "${config.networking.hostName}-sd";
         description = ''
           Specifies the Name of the Storage daemon.
         '';
       };
- 
+
       port = mkOption {
         default = 9103;
         type = types.int;
@@ -410,7 +410,7 @@ in {
           console = all
         '';
       };
- 
+
     };
 
     services.bacula-dir = {
@@ -429,7 +429,7 @@ in {
           required.
         '';
       };
- 
+
       port = mkOption {
         default = 9101;
         type = types.int;
@@ -442,7 +442,7 @@ in {
           specify DirAddresses (N.B plural) directive.
         '';
       };
- 
+
       password = mkOption {
         # TODO: required?
         description = ''
diff --git a/nixos/modules/services/backup/borgbackup.xml b/nixos/modules/services/backup/borgbackup.xml
index bef7db608f823..a197f38ffb9de 100644
--- a/nixos/modules/services/backup/borgbackup.xml
+++ b/nixos/modules/services/backup/borgbackup.xml
@@ -197,26 +197,8 @@ sudo borg init --encryption=repokey-blake2  \
     disk failure, ransomware and theft.
   </para>
   <para>
-    It is available as a flatpak package. To enable it you must set the
-    following two configuration items.
-  </para>
-  <para>
-    <programlisting>
-services.flatpak.enable = true ;
-# next line is needed to avoid the Error
-# Error deploying: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown:
-services.accounts-daemon.enable = true;
-    </programlisting>
-  </para>
-  <para>As a normal user you must first install, then run vorta using the
-    following commands:
-    <programlisting>
-flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
-flatpak install flathub com.borgbase.Vorta
-flatpak run --branch=stable --arch=x86_64 --command=vorta com.borgbase.Vorta
-</programlisting>
-    After running <code>flatpak install</code> you can start Vorta also via
-        the KDE application menu.
+   It can be installed in NixOS e.g. by adding <package>pkgs.vorta</package>
+   to <xref linkend="opt-environment.systemPackages" />.
   </para>
   <para>
     Details about using Vorta can be found under <link
diff --git a/nixos/modules/services/backup/restic.nix b/nixos/modules/services/backup/restic.nix
index 2388f1d6ca137..d869835bf07e6 100644
--- a/nixos/modules/services/backup/restic.nix
+++ b/nixos/modules/services/backup/restic.nix
@@ -31,6 +31,59 @@ in
           '';
         };
 
+        rcloneOptions = mkOption {
+          type = with types; nullOr (attrsOf (oneOf [ str bool ]));
+          default = null;
+          description = ''
+            Options to pass to rclone to control its behavior.
+            See <link xlink:href="https://rclone.org/docs/#options"/> for
+            available options. When specifying option names, strip the
+            leading <literal>--</literal>. To set a flag such as
+            <literal>--drive-use-trash</literal>, which does not take a value,
+            set the value to the Boolean <literal>true</literal>.
+          '';
+          example = {
+            bwlimit = "10M";
+            drive-use-trash = "true";
+          };
+        };
+
+        rcloneConfig = mkOption {
+          type = with types; nullOr (attrsOf (oneOf [ str bool ]));
+          default = null;
+          description = ''
+            Configuration for the rclone remote being used for backup.
+            See the remote's specific options under rclone's docs at
+            <link xlink:href="https://rclone.org/docs/"/>. When specifying
+            option names, use the "config" name specified in the docs.
+            For example, to set <literal>--b2-hard-delete</literal> for a B2
+            remote, use <literal>hard_delete = true</literal> in the
+            attribute set.
+            Warning: Secrets set in here will be world-readable in the Nix
+            store! Consider using the <literal>rcloneConfigFile</literal>
+            option instead to specify secret values separately. Note that
+            options set here will override those set in the config file.
+          '';
+          example = {
+            type = "b2";
+            account = "xxx";
+            key = "xxx";
+            hard_delete = true;
+          };
+        };
+
+        rcloneConfigFile = mkOption {
+          type = with types; nullOr path;
+          default = null;
+          description = ''
+            Path to the file containing rclone configuration. This file
+            must contain configuration for the remote specified in this backup
+            set and also must be readable by root. Options set in
+            <literal>rcloneConfig</literal> will override those set in this
+            file.
+          '';
+        };
+
         repository = mkOption {
           type = types.str;
           description = ''
@@ -170,11 +223,22 @@ in
             ( resticCmd + " forget --prune " + (concatStringsSep " " backup.pruneOpts) )
             ( resticCmd + " check" )
           ];
+          # Helper functions for rclone remotes
+          rcloneRemoteName = builtins.elemAt (splitString ":" backup.repository) 1;
+          rcloneAttrToOpt = v: "RCLONE_" + toUpper (builtins.replaceStrings [ "-" ] [ "_" ] v);
+          rcloneAttrToConf = v: "RCLONE_CONFIG_" + toUpper (rcloneRemoteName + "_" + v);
+          toRcloneVal = v: if lib.isBool v then lib.boolToString v else v;
         in nameValuePair "restic-backups-${name}" ({
           environment = {
             RESTIC_PASSWORD_FILE = backup.passwordFile;
             RESTIC_REPOSITORY = backup.repository;
-          };
+          } // optionalAttrs (backup.rcloneOptions != null) (mapAttrs' (name: value:
+            nameValuePair (rcloneAttrToOpt name) (toRcloneVal value)
+          ) backup.rcloneOptions) // optionalAttrs (backup.rcloneConfigFile != null) {
+            RCLONE_CONFIG = backup.rcloneConfigFile;
+          } // optionalAttrs (backup.rcloneConfig != null) (mapAttrs' (name: value:
+            nameValuePair (rcloneAttrToConf name) (toRcloneVal value)
+          ) backup.rcloneConfig);
           path = [ pkgs.openssh ];
           restartIfChanged = false;
           serviceConfig = {
diff --git a/nixos/modules/services/backup/zfs-replication.nix b/nixos/modules/services/backup/zfs-replication.nix
index 5a64304275d54..6d75774c78f91 100644
--- a/nixos/modules/services/backup/zfs-replication.nix
+++ b/nixos/modules/services/backup/zfs-replication.nix
@@ -18,7 +18,7 @@ in {
       };
 
       host = mkOption {
-        description = "Remote host where snapshots should be sent.";
+        description = "Remote host where snapshots should be sent. <literal>lz4</literal> is expected to be installed on this host.";
         example = "example.com";
         type = types.str;
       };
diff --git a/nixos/modules/services/backup/znapzend.nix b/nixos/modules/services/backup/znapzend.nix
index 8098617d11f3c..0ca71b413cee0 100644
--- a/nixos/modules/services/backup/znapzend.nix
+++ b/nixos/modules/services/backup/znapzend.nix
@@ -220,7 +220,7 @@ let
       };
 
       destinations = mkOption {
-        type = loaOf (destType config);
+        type = attrsOf (destType config);
         description = "Additional destinations.";
         default = {};
         example = literalExample ''
@@ -328,7 +328,7 @@ in
       };
 
       zetup = mkOption {
-        type = loaOf srcType;
+        type = attrsOf srcType;
         description = "Znapzend configuration.";
         default = {};
         example = literalExample ''
diff --git a/nixos/modules/services/cluster/kubernetes/pki.nix b/nixos/modules/services/cluster/kubernetes/pki.nix
index 4275563f1a36b..933ae481e9684 100644
--- a/nixos/modules/services/cluster/kubernetes/pki.nix
+++ b/nixos/modules/services/cluster/kubernetes/pki.nix
@@ -20,7 +20,7 @@ let
         size = 2048;
     };
     CN = top.masterAddress;
-    hosts = cfg.cfsslAPIExtraSANs;
+    hosts = [top.masterAddress] ++ cfg.cfsslAPIExtraSANs;
   });
 
   cfsslAPITokenBaseName = "apitoken.secret";
@@ -228,7 +228,8 @@ in
             };
             private_key = cert.privateKeyOptions;
             request = {
-              inherit (cert) CN hosts;
+              hosts = [cert.CN] ++ cert.hosts;
+              inherit (cert) CN;
               key = {
                 algo = "rsa";
                 size = 2048;
diff --git a/nixos/modules/services/computing/slurm/slurm.nix b/nixos/modules/services/computing/slurm/slurm.nix
index 050872e933fb1..705390a21d4ee 100644
--- a/nixos/modules/services/computing/slurm/slurm.nix
+++ b/nixos/modules/services/computing/slurm/slurm.nix
@@ -67,7 +67,7 @@ in
           type = types.bool;
           default = false;
           description = ''
-            Wether to enable the slurm control daemon.
+            Whether to enable the slurm control daemon.
             Note that the standard authentication method is "munge".
             The "munge" service needs to be provided with a password file in order for
             slurm to work properly (see <literal>services.munge.password</literal>).
@@ -135,7 +135,7 @@ in
         type = types.bool;
         default = false;
         description = ''
-          Wether to provide a slurm.conf file.
+          Whether to provide a slurm.conf file.
           Enable this option if you do not run a slurm daemon on this host
           (i.e. <literal>server.enable</literal> and <literal>client.enable</literal> are <literal>false</literal>)
           but you still want to run slurm commands from this host.
diff --git a/nixos/modules/services/computing/torque/mom.nix b/nixos/modules/services/computing/torque/mom.nix
index 83772539a7abc..0c5f43cf3e6a2 100644
--- a/nixos/modules/services/computing/torque/mom.nix
+++ b/nixos/modules/services/computing/torque/mom.nix
@@ -60,4 +60,4 @@ in
     };
 
   };
-}      
+}
diff --git a/nixos/modules/services/computing/torque/server.nix b/nixos/modules/services/computing/torque/server.nix
index 655d1500497e6..21c5a4f46724d 100644
--- a/nixos/modules/services/computing/torque/server.nix
+++ b/nixos/modules/services/computing/torque/server.nix
@@ -93,4 +93,4 @@ in
     };
 
   };
-}      
+}
diff --git a/nixos/modules/services/continuous-integration/buildbot/worker.nix b/nixos/modules/services/continuous-integration/buildbot/worker.nix
index 52f24b8cee3c3..7b8a35f54bfa3 100644
--- a/nixos/modules/services/continuous-integration/buildbot/worker.nix
+++ b/nixos/modules/services/continuous-integration/buildbot/worker.nix
@@ -29,7 +29,7 @@ let
 
     with open('${cfg.workerPassFile}', 'r', encoding='utf-8') as passwd_file:
         passwd = passwd_file.read().strip('\r\n')
-    keepalive = 600
+    keepalive = ${toString cfg.keepalive}
     umask = None
     maxdelay = 300
     numcpus = None
@@ -116,6 +116,15 @@ in {
         description = "Specifies the Buildbot Worker connection string.";
       };
 
+      keepalive = mkOption {
+        default = 600;
+        type = types.int;
+        description = "
+          This is a number that indicates how frequently keepalive messages should be sent
+          from the worker to the buildmaster, expressed in seconds.
+        ";
+      };
+
       package = mkOption {
         type = types.package;
         default = pkgs.python3Packages.buildbot-worker;
diff --git a/nixos/modules/services/continuous-integration/gitlab-runner.nix b/nixos/modules/services/continuous-integration/gitlab-runner.nix
index eacfed85ddffc..431555309cc9c 100644
--- a/nixos/modules/services/continuous-integration/gitlab-runner.nix
+++ b/nixos/modules/services/continuous-integration/gitlab-runner.nix
@@ -1,14 +1,16 @@
 { config, lib, pkgs, ... }:
+with builtins;
 with lib;
 let
   cfg = config.services.gitlab-runner;
   hasDocker = config.virtualisation.docker.enable;
-  hashedServices = with builtins; (mapAttrs' (name: service: nameValuePair
-    "${name}_${config.networking.hostName}_${
+  hashedServices = mapAttrs'
+    (name: service: nameValuePair
+      "${name}_${config.networking.hostName}_${
         substring 0 12
         (hashString "md5" (unsafeDiscardStringContext (toJSON service)))}"
       service)
-    cfg.services);
+    cfg.services;
   configPath = "$HOME/.gitlab-runner/config.toml";
   configureScript = pkgs.writeShellScriptBin "gitlab-runner-configure" (
     if (cfg.configFile != null) then ''
@@ -47,6 +49,8 @@ let
           ] ++ service.registrationFlags
             ++ optional (service.buildsDir != null)
             "--builds-dir ${service.buildsDir}"
+            ++ optional (service.cloneUrl != null)
+            "--clone-url ${service.cloneUrl}"
             ++ optional (service.preCloneScript != null)
             "--pre-clone-script ${service.preCloneScript}"
             ++ optional (service.preBuildScript != null)
@@ -76,7 +80,7 @@ let
               ++ map (v: "--docker-allowed-images ${escapeShellArg v}") service.dockerAllowedImages
               ++ map (v: "--docker-allowed-services ${escapeShellArg v}") service.dockerAllowedServices
             )
-          ))} && sleep 1
+          ))} && sleep 1 || exit 1
         fi
       '') hashedServices)}
 
@@ -89,8 +93,17 @@ let
 
       # update global options
       remarshal --if toml --of json ${configPath} \
-        | jq -cM '.check_interval = ${toString cfg.checkInterval} |
-                  .concurrent = ${toString cfg.concurrent}' \
+        | jq -cM ${escapeShellArg (concatStringsSep " | " [
+            ".check_interval = ${toJSON cfg.checkInterval}"
+            ".concurrent = ${toJSON cfg.concurrent}"
+            ".sentry_dsn = ${toJSON cfg.sentryDSN}"
+            ".listen_address = ${toJSON cfg.prometheusListenAddress}"
+            ".session_server.listen_address = ${toJSON cfg.sessionServer.listenAddress}"
+            ".session_server.advertise_address = ${toJSON cfg.sessionServer.advertiseAddress}"
+            ".session_server.session_timeout = ${toJSON cfg.sessionServer.sessionTimeout}"
+            "del(.[] | nulls)"
+            "del(.session_server[] | nulls)"
+          ])} \
         | remarshal --if json --of toml \
         | sponge ${configPath}
 
@@ -141,6 +154,66 @@ in
         0 does not mean unlimited.
       '';
     };
+    sentryDSN = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      example = "https://public:private@host:port/1";
+      description = ''
+        Data Source Name for tracking of all system level errors to Sentry.
+      '';
+    };
+    prometheusListenAddress = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      example = "localhost:8080";
+      description = ''
+        Address (&lt;host&gt;:&lt;port&gt;) on which the Prometheus metrics HTTP server
+        should be listening.
+      '';
+    };
+    sessionServer = mkOption {
+      type = types.submodule {
+        options = {
+          listenAddress = mkOption {
+            type = types.nullOr types.str;
+            default = null;
+            example = "0.0.0.0:8093";
+            description = ''
+              An internal URL to be used for the session server.
+            '';
+          };
+          advertiseAddress = mkOption {
+            type = types.nullOr types.str;
+            default = null;
+            example = "runner-host-name.tld:8093";
+            description = ''
+              The URL that the Runner will expose to GitLab to be used
+              to access the session server.
+              Fallbacks to <option>listenAddress</option> if not defined.
+            '';
+          };
+          sessionTimeout = mkOption {
+            type = types.int;
+            default = 1800;
+            description = ''
+              How long in seconds the session can stay active after
+              the job completes (which will block the job from finishing).
+            '';
+          };
+        };
+      };
+      default = { };
+      example = literalExample ''
+        {
+          listenAddress = "0.0.0.0:8093";
+        }
+      '';
+      description = ''
+        The session server allows the user to interact with jobs
+        that the Runner is responsible for. A good example of this is the
+        <link xlink:href="https://docs.gitlab.com/ee/ci/interactive_web_terminal/index.html">interactive web terminal</link>.
+      '';
+    };
     gracefulTermination = mkOption {
       type = types.bool;
       default = false;
@@ -306,6 +379,14 @@ in
               in context of selected executor (Locally, Docker, SSH).
             '';
           };
+          cloneUrl = mkOption {
+            type = types.nullOr types.str;
+            default = null;
+            example = "http://gitlab.example.local";
+            description = ''
+              Overwrite the URL for the GitLab instance. Used if the Runner can’t connect to GitLab on the URL GitLab exposes itself.
+            '';
+          };
           dockerImage = mkOption {
             type = types.nullOr types.str;
             default = null;
diff --git a/nixos/modules/services/continuous-integration/hercules-ci-agent/common.nix b/nixos/modules/services/continuous-integration/hercules-ci-agent/common.nix
new file mode 100644
index 0000000000000..4aed493c0fb0a
--- /dev/null
+++ b/nixos/modules/services/continuous-integration/hercules-ci-agent/common.nix
@@ -0,0 +1,213 @@
+/*
+
+This file is for options that NixOS and nix-darwin have in common.
+
+Platform-specific code is in the respective default.nix files.
+
+ */
+
+{ config, lib, options, pkgs, ... }:
+
+let
+  inherit (lib) mkOption mkIf types filterAttrs literalExample mkRenamedOptionModule;
+
+  cfg =
+    config.services.hercules-ci-agent;
+
+  format = pkgs.formats.toml {};
+
+  settingsModule = { config, ... }: {
+    freeformType = format.type;
+    options = {
+      baseDirectory = mkOption {
+        type = types.path;
+        default = "/var/lib/hercules-ci-agent";
+        description = ''
+          State directory (secrets, work directory, etc) for agent
+        '';
+      };
+      concurrentTasks = mkOption {
+        description = ''
+          Number of tasks to perform simultaneously, such as evaluations, derivations.
+
+          You must have a total capacity across agents of at least 2 concurrent tasks on <literal>x86_64-linux</literal>
+          to allow for import from derivation.
+        '';
+        type = types.int;
+        default = 4;
+      };
+      workDirectory = mkOption {
+        description = ''
+          The directory in which temporary subdirectories are created for task state. This includes sources for Nix evaluation.
+        '';
+        type = types.path;
+        default = config.baseDirectory + "/work";
+        defaultText = literalExample ''baseDirectory + "/work"'';
+      };
+      staticSecretsDirectory = mkOption {
+        description = ''
+          This is the default directory to look for statically configured secrets like <literal>cluster-join-token.key</literal>.
+        '';
+        type = types.path;
+        default = config.baseDirectory + "/secrets";
+        defaultText = literalExample ''baseDirectory + "/secrets"'';
+      };
+      clusterJoinTokenPath = mkOption {
+        description = ''
+          Location of the cluster-join-token.key file.
+        '';
+        type = types.path;
+        default = config.staticSecretsDirectory + "/cluster-join-token.key";
+        defaultText = literalExample ''staticSecretsDirectory + "/cluster-join-token.key"'';
+        # internal: It's a bit too detailed to show by default in the docs,
+        # but useful to define explicitly to allow reuse by other modules.
+        internal = true;
+      };
+      binaryCachesPath = mkOption {
+        description = ''
+          Location of the binary-caches.json file.
+        '';
+        type = types.path;
+        default = config.staticSecretsDirectory + "/binary-caches.json";
+        defaultText = literalExample ''staticSecretsDirectory + "/binary-caches.json"'';
+        # internal: It's a bit too detailed to show by default in the docs,
+        # but useful to define explicitly to allow reuse by other modules.
+        internal = true;
+      };
+    };
+  };
+
+  checkNix =
+    if !cfg.checkNix
+    then ""
+    else if lib.versionAtLeast config.nix.package.version "2.4.0"
+    then ""
+    else pkgs.stdenv.mkDerivation {
+      name = "hercules-ci-check-system-nix-src";
+      inherit (config.nix.package) src patches;
+      configurePhase = ":";
+      buildPhase = ''
+        echo "Checking in-memory pathInfoCache expiry"
+        if ! grep 'struct PathInfoCacheValue' src/libstore/store-api.hh >/dev/null; then
+          cat 1>&2 <<EOF
+
+          You are deploying Hercules CI Agent on a system with an incompatible
+          nix-daemon. Please
+           - either upgrade Nix to version 2.4.0 (when released),
+           - or set option services.hercules-ci-agent.patchNix = true;
+           - or set option nix.package to a build of Nix 2.3 with this patch applied:
+               https://github.com/NixOS/nix/pull/3405
+
+          The patch is required for Nix-daemon clients that expect a change in binary
+          cache contents while running, like the agent's evaluator. Without it, import
+          from derivation will fail if your cluster has more than one machine.
+          We are conservative with changes to the overall system, which is why we
+          keep changes to a minimum and why we ask for confirmation in the form of
+          services.hercules-ci-agent.patchNix = true before applying.
+
+        EOF
+          exit 1
+        fi
+      '';
+      installPhase = "touch $out";
+    };
+
+  patchedNix = lib.mkIf (!lib.versionAtLeast pkgs.nix.version "2.4.0") (
+    if lib.versionAtLeast pkgs.nix.version "2.4pre"
+    then lib.warn "Hercules CI Agent module will not patch 2.4 pre-release. Make sure it includes (equivalently) PR #3043, commit d048577909 or is no older than 2020-03-13." pkgs.nix
+    else pkgs.nix.overrideAttrs (
+      o: {
+        patches = (o.patches or []) ++ [ backportNix3398 ];
+      }
+    )
+  );
+
+  backportNix3398 = pkgs.fetchurl {
+    url = "https://raw.githubusercontent.com/hercules-ci/hercules-ci-agent/hercules-ci-agent-0.7.3/for-upstream/issue-3398-path-info-cache-ttls-backport-2.3.patch";
+    sha256 = "0jfckqjir9il2il7904yc1qyadw366y7xqzg81sp9sl3f1pw70ib";
+  };
+in
+{
+  imports = [
+    (mkRenamedOptionModule ["services" "hercules-ci-agent" "extraOptions"] ["services" "hercules-ci-agent" "settings"])
+    (mkRenamedOptionModule ["services" "hercules-ci-agent" "baseDirectory"] ["services" "hercules-ci-agent" "settings" "baseDirectory"])
+    (mkRenamedOptionModule ["services" "hercules-ci-agent" "concurrentTasks"] ["services" "hercules-ci-agent" "settings" "concurrentTasks"])
+  ];
+
+  options.services.hercules-ci-agent = {
+    enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Enable to run Hercules CI Agent as a system service.
+
+        <link xlink:href="https://hercules-ci.com">Hercules CI</link> is a
+        continuous integation service that is centered around Nix.
+
+        Support is available at <link xlink:href="mailto:help@hercules-ci.com">help@hercules-ci.com</link>.
+      '';
+    };
+    patchNix = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Fix Nix 2.3 cache path metadata caching behavior. Has the effect of <literal>nix.package = patch pkgs.nix;</literal>
+
+        This option will be removed when Hercules CI Agent moves to Nix 2.4 (upcoming Nix release).
+      '';
+    };
+    checkNix = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        Whether to make sure that the system's Nix (nix-daemon) is compatible.
+
+        If you set this to false, please keep up with the change log.
+      '';
+    };
+    package = mkOption {
+      description = ''
+        Package containing the bin/hercules-ci-agent executable.
+      '';
+      type = types.package;
+      default = pkgs.hercules-ci-agent;
+      defaultText = literalExample "pkgs.hercules-ci-agent";
+    };
+    settings = mkOption {
+      description = ''
+        These settings are written to the <literal>agent.toml</literal> file.
+
+        Not all settings are listed as options, can be set nonetheless.
+
+        For the exhaustive list of settings, see <link xlink:href="https://docs.hercules-ci.com/hercules-ci/reference/agent-config/"/>.
+      '';
+      type = types.submoduleWith { modules = [ settingsModule ]; };
+    };
+
+    /*
+      Internal and/or computed values.
+
+      These are written as options instead of let binding to allow sharing with
+      default.nix on both NixOS and nix-darwin.
+     */
+    tomlFile = mkOption {
+      type = types.path;
+      internal = true;
+      defaultText = "generated hercules-ci-agent.toml";
+      description = ''
+        The fully assembled config file.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    nix.extraOptions = lib.addContextFrom checkNix ''
+      # A store path that was missing at first may well have finished building,
+      # even shortly after the previous lookup. This *also* applies to the daemon.
+      narinfo-cache-negative-ttl = 0
+    '';
+    nix.package = mkIf cfg.patchNix patchedNix;
+    services.hercules-ci-agent.tomlFile =
+      format.generate "hercules-ci-agent.toml" cfg.settings;
+  };
+}
diff --git a/nixos/modules/services/continuous-integration/hercules-ci-agent/default.nix b/nixos/modules/services/continuous-integration/hercules-ci-agent/default.nix
new file mode 100644
index 0000000000000..d2e7e8e18f94e
--- /dev/null
+++ b/nixos/modules/services/continuous-integration/hercules-ci-agent/default.nix
@@ -0,0 +1,86 @@
+/*
+
+This file is for NixOS-specific options and configs.
+
+Code that is shared with nix-darwin goes in common.nix.
+
+ */
+
+{ pkgs, config, lib, ... }:
+
+let
+
+  inherit (lib) mkIf mkDefault;
+
+  cfg = config.services.hercules-ci-agent;
+
+  command = "${cfg.package}/bin/hercules-ci-agent --config ${cfg.tomlFile}";
+  testCommand = "${command} --test-configuration";
+
+in
+{
+  imports = [
+    ./common.nix
+    (lib.mkRenamedOptionModule ["services" "hercules-ci-agent" "user"] ["systemd" "services" "hercules-ci-agent" "serviceConfig" "User"])
+  ];
+
+  config = mkIf cfg.enable {
+
+    systemd.services.hercules-ci-agent = {
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network-online.target" ];
+      wants = [ "network-online.target" ];
+      path = [ config.nix.package ];
+      serviceConfig = {
+        User = "hercules-ci-agent";
+        ExecStart = command;
+        ExecStartPre = testCommand;
+        Restart = "on-failure";
+        RestartSec = 120;
+        StartLimitBurst = 30 * 1000000; # practically infinite
+      };
+    };
+
+    # Changes in the secrets do not affect the unit in any way that would cause
+    # a restart, which is currently necessary to reload the secrets.
+    systemd.paths.hercules-ci-agent-restart-files = {
+      wantedBy = [ "hercules-ci-agent.service" ];
+      pathConfig = {
+        Unit = "hercules-ci-agent-restarter.service";
+        PathChanged = [ cfg.settings.clusterJoinTokenPath cfg.settings.binaryCachesPath ];
+      };
+    };
+    systemd.services.hercules-ci-agent-restarter = {
+      serviceConfig.Type = "oneshot";
+      script = ''
+        # Wait a bit, with the effect of bundling up file changes into a single
+        # run of this script and hopefully a single restart.
+        sleep 10
+        if systemctl is-active --quiet hercules-ci-agent.service; then
+          if ${testCommand}; then
+            systemctl restart hercules-ci-agent.service
+          else
+            echo 1>&2 "WARNING: Not restarting agent because config is not valid at this time."
+          fi
+        else
+          echo 1>&2 "Not restarting hercules-ci-agent despite config file update, because it is not already active."
+        fi
+      '';
+    };
+
+    # Trusted user allows simplified configuration and better performance
+    # when operating in a cluster.
+    nix.trustedUsers = [ config.systemd.services.hercules-ci-agent.serviceConfig.User ];
+    services.hercules-ci-agent.settings.nixUserIsTrusted = true;
+
+    users.users.hercules-ci-agent = {
+      home = cfg.settings.baseDirectory;
+      createHome = true;
+      group = "hercules-ci-agent";
+      description = "Hercules CI Agent system user";
+      isSystemUser = true;
+    };
+
+    users.groups.hercules-ci-agent = {};
+  };
+}
diff --git a/nixos/modules/services/databases/couchdb.nix b/nixos/modules/services/databases/couchdb.nix
index 53224db1d8961..f385331e87823 100644
--- a/nixos/modules/services/databases/couchdb.nix
+++ b/nixos/modules/services/databases/couchdb.nix
@@ -11,7 +11,13 @@ let
       database_dir = ${cfg.databaseDir}
       uri_file = ${cfg.uriFile}
       view_index_dir = ${cfg.viewIndexDir}
-    '' + (if useVersion2 then
+    '' + (if cfg.adminPass != null then
+    ''
+      [admins]
+      ${cfg.adminUser} = ${cfg.adminPass}
+    '' else
+    ''
+    '') + (if useVersion2 then
     ''
       [chttpd]
     '' else
@@ -54,6 +60,23 @@ in {
         '';
       };
 
+      adminUser = mkOption {
+        type = types.str;
+        default = "admin";
+        description = ''
+          Couchdb (i.e. fauxton) account with permission for all dbs and
+          tasks.
+        '';
+      };
+
+      adminPass = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = ''
+          Couchdb (i.e. fauxton) account with permission for all dbs and
+          tasks.
+        '';
+      };
 
       user = mkOption {
         type = types.str;
diff --git a/nixos/modules/services/databases/mysql.nix b/nixos/modules/services/databases/mysql.nix
index 2e8c5b7640b2c..7d0a3f9afc48c 100644
--- a/nixos/modules/services/databases/mysql.nix
+++ b/nixos/modules/services/databases/mysql.nix
@@ -6,12 +6,10 @@ let
 
   cfg = config.services.mysql;
 
-  mysql = cfg.package;
-
-  isMariaDB = lib.getName mysql == lib.getName pkgs.mariadb;
+  isMariaDB = lib.getName cfg.package == lib.getName pkgs.mariadb;
 
   mysqldOptions =
-    "--user=${cfg.user} --datadir=${cfg.dataDir} --basedir=${mysql}";
+    "--user=${cfg.user} --datadir=${cfg.dataDir} --basedir=${cfg.package}";
 
   settingsFile = pkgs.writeText "my.cnf" (
     generators.toINI { listsAsDuplicateKeys = true; } cfg.settings +
@@ -22,7 +20,7 @@ in
 
 {
   imports = [
-    (mkRemovedOptionModule [ "services" "mysql" "pidDir" ] "Don't wait for pidfiles, describe dependencies through systemd")
+    (mkRemovedOptionModule [ "services" "mysql" "pidDir" ] "Don't wait for pidfiles, describe dependencies through systemd.")
     (mkRemovedOptionModule [ "services" "mysql" "rootPassword" ] "Use socket authentication or set the password outside of the nix store.")
   ];
 
@@ -46,25 +44,31 @@ in
         type = types.nullOr types.str;
         default = null;
         example = literalExample "0.0.0.0";
-        description = "Address to bind to. The default is to bind to all addresses";
+        description = "Address to bind to. The default is to bind to all addresses.";
       };
 
       port = mkOption {
         type = types.int;
         default = 3306;
-        description = "Port of MySQL";
+        description = "Port of MySQL.";
       };
 
       user = mkOption {
         type = types.str;
         default = "mysql";
-        description = "User account under which MySQL runs";
+        description = "User account under which MySQL runs.";
+      };
+
+      group = mkOption {
+        type = types.str;
+        default = "mysql";
+        description = "Group under which MySQL runs.";
       };
 
       dataDir = mkOption {
         type = types.path;
         example = "/var/lib/mysql";
-        description = "Location where MySQL stores its table files";
+        description = "Location where MySQL stores its table files.";
       };
 
       configFile = mkOption {
@@ -171,7 +175,7 @@ in
       initialScript = mkOption {
         type = types.nullOr types.path;
         default = null;
-        description = "A file containing SQL statements to be executed on the first startup. Can be used for granting certain permissions on the database";
+        description = "A file containing SQL statements to be executed on the first startup. Can be used for granting certain permissions on the database.";
       };
 
       ensureDatabases = mkOption {
@@ -259,33 +263,33 @@ in
         serverId = mkOption {
           type = types.int;
           default = 1;
-          description = "Id of the MySQL server instance. This number must be unique for each instance";
+          description = "Id of the MySQL server instance. This number must be unique for each instance.";
         };
 
         masterHost = mkOption {
           type = types.str;
-          description = "Hostname of the MySQL master server";
+          description = "Hostname of the MySQL master server.";
         };
 
         slaveHost = mkOption {
           type = types.str;
-          description = "Hostname of the MySQL slave server";
+          description = "Hostname of the MySQL slave server.";
         };
 
         masterUser = mkOption {
           type = types.str;
-          description = "Username of the MySQL replication user";
+          description = "Username of the MySQL replication user.";
         };
 
         masterPassword = mkOption {
           type = types.str;
-          description = "Password of the MySQL replication user";
+          description = "Password of the MySQL replication user.";
         };
 
         masterPort = mkOption {
           type = types.int;
           default = 3306;
-          description = "Port number on which the MySQL master server runs";
+          description = "Port number on which the MySQL master server runs.";
         };
       };
     };
@@ -317,29 +321,33 @@ in
         binlog-ignore-db = [ "information_schema" "performance_schema" "mysql" ];
       })
       (mkIf (!isMariaDB) {
-        plugin-load-add = optional (cfg.ensureUsers != []) "auth_socket.so";
+        plugin-load-add = "auth_socket.so";
       })
     ];
 
-    users.users.mysql = {
-      description = "MySQL server user";
-      group = "mysql";
-      uid = config.ids.uids.mysql;
+    users.users = optionalAttrs (cfg.user == "mysql") {
+      mysql = {
+        description = "MySQL server user";
+        group = cfg.group;
+        uid = config.ids.uids.mysql;
+      };
     };
 
-    users.groups.mysql.gid = config.ids.gids.mysql;
+    users.groups = optionalAttrs (cfg.group == "mysql") {
+      mysql.gid = config.ids.gids.mysql;
+    };
 
-    environment.systemPackages = [mysql];
+    environment.systemPackages = [ cfg.package ];
 
     environment.etc."my.cnf".source = cfg.configFile;
 
     systemd.tmpfiles.rules = [
-      "d '${cfg.dataDir}' 0700 ${cfg.user} mysql - -"
-      "z '${cfg.dataDir}' 0700 ${cfg.user} mysql - -"
+      "d '${cfg.dataDir}' 0700 '${cfg.user}' '${cfg.group}' - -"
+      "z '${cfg.dataDir}' 0700 '${cfg.user}' '${cfg.group}' - -"
     ];
 
     systemd.services.mysql = let
-      hasNotify = (cfg.package == pkgs.mariadb);
+      hasNotify = isMariaDB;
     in {
         description = "MySQL Server";
 
@@ -357,125 +365,127 @@ in
 
         preStart = if isMariaDB then ''
           if ! test -e ${cfg.dataDir}/mysql; then
-            ${mysql}/bin/mysql_install_db --defaults-file=/etc/my.cnf ${mysqldOptions}
+            ${cfg.package}/bin/mysql_install_db --defaults-file=/etc/my.cnf ${mysqldOptions}
             touch ${cfg.dataDir}/mysql_init
           fi
         '' else ''
           if ! test -e ${cfg.dataDir}/mysql; then
-            ${mysql}/bin/mysqld --defaults-file=/etc/my.cnf ${mysqldOptions} --initialize-insecure
+            ${cfg.package}/bin/mysqld --defaults-file=/etc/my.cnf ${mysqldOptions} --initialize-insecure
             touch ${cfg.dataDir}/mysql_init
           fi
         '';
 
-        serviceConfig = {
-          Type = if hasNotify then "notify" else "simple";
-          Restart = "on-abort";
-          RestartSec = "5s";
-          # The last two environment variables are used for starting Galera clusters
-          ExecStart = "${mysql}/bin/mysqld --defaults-file=/etc/my.cnf ${mysqldOptions} $_WSREP_NEW_CLUSTER $_WSREP_START_POSITION";
-          ExecStartPost =
-            let
-              setupScript = pkgs.writeScript "mysql-setup" ''
-                #!${pkgs.runtimeShell} -e
-
-                ${optionalString (!hasNotify) ''
-                  # Wait until the MySQL server is available for use
-                  count=0
-                  while [ ! -e /run/mysqld/mysqld.sock ]
-                  do
-                      if [ $count -eq 30 ]
-                      then
-                          echo "Tried 30 times, giving up..."
-                          exit 1
-                      fi
-
-                      echo "MySQL daemon not yet started. Waiting for 1 second..."
-                      count=$((count++))
-                      sleep 1
-                  done
-                ''}
-
-                if [ -f ${cfg.dataDir}/mysql_init ]
+        postStart = let
+          # The super user account to use on *first* run of MySQL server
+          superUser = if isMariaDB then cfg.user else "root";
+        in ''
+          ${optionalString (!hasNotify) ''
+            # Wait until the MySQL server is available for use
+            count=0
+            while [ ! -e /run/mysqld/mysqld.sock ]
+            do
+                if [ $count -eq 30 ]
                 then
-                    ${concatMapStrings (database: ''
-                      # Create initial databases
-                      if ! test -e "${cfg.dataDir}/${database.name}"; then
-                          echo "Creating initial database: ${database.name}"
-                          ( echo 'create database `${database.name}`;'
-
-                            ${optionalString (database.schema != null) ''
-                            echo 'use `${database.name}`;'
-
-                            # TODO: this silently falls through if database.schema does not exist,
-                            # we should catch this somehow and exit, but can't do it here because we're in a subshell.
-                            if [ -f "${database.schema}" ]
-                            then
-                                cat ${database.schema}
-                            elif [ -d "${database.schema}" ]
-                            then
-                                cat ${database.schema}/mysql-databases/*.sql
-                            fi
-                            ''}
-                          ) | ${mysql}/bin/mysql -u root -N
-                      fi
-                    '') cfg.initialDatabases}
-
-                    ${optionalString (cfg.replication.role == "master")
-                      ''
-                        # Set up the replication master
+                    echo "Tried 30 times, giving up..."
+                    exit 1
+                fi
 
-                        ( echo "use mysql;"
-                          echo "CREATE USER '${cfg.replication.masterUser}'@'${cfg.replication.slaveHost}' IDENTIFIED WITH mysql_native_password;"
-                          echo "SET PASSWORD FOR '${cfg.replication.masterUser}'@'${cfg.replication.slaveHost}' = PASSWORD('${cfg.replication.masterPassword}');"
-                          echo "GRANT REPLICATION SLAVE ON *.* TO '${cfg.replication.masterUser}'@'${cfg.replication.slaveHost}';"
-                        ) | ${mysql}/bin/mysql -u root -N
+                echo "MySQL daemon not yet started. Waiting for 1 second..."
+                count=$((count++))
+                sleep 1
+            done
+          ''}
+
+          if [ -f ${cfg.dataDir}/mysql_init ]
+          then
+              # While MariaDB comes with a 'mysql' super user account since 10.4.x, MySQL does not
+              # Since we don't want to run this service as 'root' we need to ensure the account exists on first run
+              ( echo "CREATE USER IF NOT EXISTS '${cfg.user}'@'localhost' IDENTIFIED WITH ${if isMariaDB then "unix_socket" else "auth_socket"};"
+                echo "GRANT ALL PRIVILEGES ON *.* TO '${cfg.user}'@'localhost' WITH GRANT OPTION;"
+              ) | ${cfg.package}/bin/mysql -u ${superUser} -N
+
+              ${concatMapStrings (database: ''
+                # Create initial databases
+                if ! test -e "${cfg.dataDir}/${database.name}"; then
+                    echo "Creating initial database: ${database.name}"
+                    ( echo 'create database `${database.name}`;'
+
+                      ${optionalString (database.schema != null) ''
+                      echo 'use `${database.name}`;'
+
+                      # TODO: this silently falls through if database.schema does not exist,
+                      # we should catch this somehow and exit, but can't do it here because we're in a subshell.
+                      if [ -f "${database.schema}" ]
+                      then
+                          cat ${database.schema}
+                      elif [ -d "${database.schema}" ]
+                      then
+                          cat ${database.schema}/mysql-databases/*.sql
+                      fi
                       ''}
+                    ) | ${cfg.package}/bin/mysql -u ${superUser} -N
+                fi
+              '') cfg.initialDatabases}
 
-                    ${optionalString (cfg.replication.role == "slave")
-                      ''
-                        # Set up the replication slave
+              ${optionalString (cfg.replication.role == "master")
+                ''
+                  # Set up the replication master
 
-                        ( echo "stop slave;"
-                          echo "change master to master_host='${cfg.replication.masterHost}', master_user='${cfg.replication.masterUser}', master_password='${cfg.replication.masterPassword}';"
-                          echo "start slave;"
-                        ) | ${mysql}/bin/mysql -u root -N
-                      ''}
+                  ( echo "use mysql;"
+                    echo "CREATE USER '${cfg.replication.masterUser}'@'${cfg.replication.slaveHost}' IDENTIFIED WITH mysql_native_password;"
+                    echo "SET PASSWORD FOR '${cfg.replication.masterUser}'@'${cfg.replication.slaveHost}' = PASSWORD('${cfg.replication.masterPassword}');"
+                    echo "GRANT REPLICATION SLAVE ON *.* TO '${cfg.replication.masterUser}'@'${cfg.replication.slaveHost}';"
+                  ) | ${cfg.package}/bin/mysql -u ${superUser} -N
+                ''}
 
-                    ${optionalString (cfg.initialScript != null)
-                      ''
-                        # Execute initial script
-                        # using toString to avoid copying the file to nix store if given as path instead of string,
-                        # as it might contain credentials
-                        cat ${toString cfg.initialScript} | ${mysql}/bin/mysql -u root -N
-                      ''}
+              ${optionalString (cfg.replication.role == "slave")
+                ''
+                  # Set up the replication slave
 
-                    rm ${cfg.dataDir}/mysql_init
-                fi
+                  ( echo "stop slave;"
+                    echo "change master to master_host='${cfg.replication.masterHost}', master_user='${cfg.replication.masterUser}', master_password='${cfg.replication.masterPassword}';"
+                    echo "start slave;"
+                  ) | ${cfg.package}/bin/mysql -u ${superUser} -N
+                ''}
 
-                ${optionalString (cfg.ensureDatabases != []) ''
-                  (
-                  ${concatMapStrings (database: ''
-                    echo "CREATE DATABASE IF NOT EXISTS \`${database}\`;"
-                  '') cfg.ensureDatabases}
-                  ) | ${mysql}/bin/mysql -u root -N
+              ${optionalString (cfg.initialScript != null)
+                ''
+                  # Execute initial script
+                  # using toString to avoid copying the file to nix store if given as path instead of string,
+                  # as it might contain credentials
+                  cat ${toString cfg.initialScript} | ${cfg.package}/bin/mysql -u ${superUser} -N
                 ''}
 
-                ${concatMapStrings (user:
-                  ''
-                    ( echo "CREATE USER IF NOT EXISTS '${user.name}'@'localhost' IDENTIFIED WITH ${if isMariaDB then "unix_socket" else "auth_socket"};"
-                      ${concatStringsSep "\n" (mapAttrsToList (database: permission: ''
-                        echo "GRANT ${permission} ON ${database} TO '${user.name}'@'localhost';"
-                      '') user.ensurePermissions)}
-                    ) | ${mysql}/bin/mysql -u root -N
-                  '') cfg.ensureUsers}
-              '';
-            in
-              # ensureDatbases & ensureUsers depends on this script being run as root
-              # when the user has secured their mysql install
-              "+${setupScript}";
+              rm ${cfg.dataDir}/mysql_init
+          fi
+
+          ${optionalString (cfg.ensureDatabases != []) ''
+            (
+            ${concatMapStrings (database: ''
+              echo "CREATE DATABASE IF NOT EXISTS \`${database}\`;"
+            '') cfg.ensureDatabases}
+            ) | ${cfg.package}/bin/mysql -N
+          ''}
+
+          ${concatMapStrings (user:
+            ''
+              ( echo "CREATE USER IF NOT EXISTS '${user.name}'@'localhost' IDENTIFIED WITH ${if isMariaDB then "unix_socket" else "auth_socket"};"
+                ${concatStringsSep "\n" (mapAttrsToList (database: permission: ''
+                  echo "GRANT ${permission} ON ${database} TO '${user.name}'@'localhost';"
+                '') user.ensurePermissions)}
+              ) | ${cfg.package}/bin/mysql -N
+            '') cfg.ensureUsers}
+        '';
+
+        serviceConfig = {
+          Type = if hasNotify then "notify" else "simple";
+          Restart = "on-abort";
+          RestartSec = "5s";
+          # The last two environment variables are used for starting Galera clusters
+          ExecStart = "${cfg.package}/bin/mysqld --defaults-file=/etc/my.cnf ${mysqldOptions} $_WSREP_NEW_CLUSTER $_WSREP_START_POSITION";
           # User and group
           User = cfg.user;
-          Group = "mysql";
+          Group = cfg.group;
           # Runtime directory and mode
           RuntimeDirectory = "mysqld";
           RuntimeDirectoryMode = "0755";
diff --git a/nixos/modules/services/databases/openldap.nix b/nixos/modules/services/databases/openldap.nix
index 9b4d9a98b745e..7472538b887e3 100644
--- a/nixos/modules/services/databases/openldap.nix
+++ b/nixos/modules/services/databases/openldap.nix
@@ -5,14 +5,14 @@ with lib;
 let
 
   cfg = config.services.openldap;
-  openldap = pkgs.openldap;
+  openldap = cfg.package;
 
   dataFile = pkgs.writeText "ldap-contents.ldif" cfg.declarativeContents;
   configFile = pkgs.writeText "slapd.conf" ((optionalString cfg.defaultSchemas ''
-    include ${pkgs.openldap.out}/etc/schema/core.schema
-    include ${pkgs.openldap.out}/etc/schema/cosine.schema
-    include ${pkgs.openldap.out}/etc/schema/inetorgperson.schema
-    include ${pkgs.openldap.out}/etc/schema/nis.schema
+    include ${openldap.out}/etc/schema/core.schema
+    include ${openldap.out}/etc/schema/cosine.schema
+    include ${openldap.out}/etc/schema/inetorgperson.schema
+    include ${openldap.out}/etc/schema/nis.schema
   '') + ''
     ${cfg.extraConfig}
     database ${cfg.database}
@@ -46,6 +46,18 @@ in
         ";
       };
 
+      package = mkOption {
+        type = types.package;
+        default = pkgs.openldap;
+        description = ''
+          OpenLDAP package to use.
+
+          This can be used to, for example, set an OpenLDAP package
+          with custom overrides to enable modules or other
+          functionality.
+        '';
+      };
+
       user = mkOption {
         type = types.str;
         default = "openldap";
@@ -152,10 +164,10 @@ in
         ";
         example = literalExample ''
             '''
-            include ${pkgs.openldap.out}/etc/schema/core.schema
-            include ${pkgs.openldap.out}/etc/schema/cosine.schema
-            include ${pkgs.openldap.out}/etc/schema/inetorgperson.schema
-            include ${pkgs.openldap.out}/etc/schema/nis.schema
+            include ${openldap.out}/etc/schema/core.schema
+            include ${openldap.out}/etc/schema/cosine.schema
+            include ${openldap.out}/etc/schema/inetorgperson.schema
+            include ${openldap.out}/etc/schema/nis.schema
 
             database bdb
             suffix dc=example,dc=org
diff --git a/nixos/modules/services/databases/postgresql.nix b/nixos/modules/services/databases/postgresql.nix
index 579b6a4d9c672..5056d50153f6d 100644
--- a/nixos/modules/services/databases/postgresql.nix
+++ b/nixos/modules/services/databases/postgresql.nix
@@ -11,23 +11,23 @@ let
       then cfg.package
       else cfg.package.withPackages (_: cfg.extraPlugins);
 
+  toStr = value:
+    if true == value then "yes"
+    else if false == value then "no"
+    else if isString value then "'${lib.replaceStrings ["'"] ["''"] value}'"
+    else toString value;
+
   # The main PostgreSQL configuration file.
-  configFile = pkgs.writeText "postgresql.conf"
-    ''
-      hba_file = '${pkgs.writeText "pg_hba.conf" cfg.authentication}'
-      ident_file = '${pkgs.writeText "pg_ident.conf" cfg.identMap}'
-      log_destination = 'stderr'
-      log_line_prefix = '${cfg.logLinePrefix}'
-      listen_addresses = '${if cfg.enableTCPIP then "*" else "localhost"}'
-      port = ${toString cfg.port}
-      ${cfg.extraConfig}
-    ''; 
+  configFile = pkgs.writeText "postgresql.conf" (concatStringsSep "\n" (mapAttrsToList (n: v: "${n} = ${toStr v}") cfg.settings));
 
   groupAccessAvailable = versionAtLeast postgresql.version "11.0";
 
 in
 
 {
+  imports = [
+    (mkRemovedOptionModule [ "services" "postgresql" "extraConfig" ] "Use services.postgresql.settings instead.")
+  ];
 
   ###### interface
 
@@ -55,9 +55,13 @@ in
 
       dataDir = mkOption {
         type = types.path;
+        defaultText = "/var/lib/postgresql/\${config.services.postgresql.package.psqlSchema}";
         example = "/var/lib/postgresql/11";
         description = ''
-          Data directory for PostgreSQL.
+          The data directory for PostgreSQL. If left as the default value
+          this directory will automatically be created before the PostgreSQL server starts, otherwise
+          the sysadmin is responsible for ensuring the directory exists with appropriate ownership
+          and permissions.
         '';
       };
 
@@ -208,10 +212,28 @@ in
         '';
       };
 
-      extraConfig = mkOption {
-        type = types.lines;
-        default = "";
-        description = "Additional text to be appended to <filename>postgresql.conf</filename>.";
+      settings = mkOption {
+        type = with types; attrsOf (oneOf [ bool float int str ]);
+        default = {};
+        description = ''
+          PostgreSQL configuration. Refer to
+          <link xlink:href="https://www.postgresql.org/docs/11/config-setting.html#CONFIG-SETTING-CONFIGURATION-FILE"/>
+          for an overview of <literal>postgresql.conf</literal>.
+
+          <note><para>
+            String values will automatically be enclosed in single quotes. Single quotes will be
+            escaped with two single quotes as described by the upstream documentation linked above.
+          </para></note>
+        '';
+        example = literalExample ''
+          {
+            log_connections = true;
+            log_statement = "all";
+            logging_collector = true
+            log_disconnections = true
+            log_destination = lib.mkForce "syslog";
+          }
+        '';
       };
 
       recoveryConfig = mkOption {
@@ -221,14 +243,15 @@ in
           Contents of the <filename>recovery.conf</filename> file.
         '';
       };
+
       superUser = mkOption {
         type = types.str;
-        default= if versionAtLeast config.system.stateVersion "17.09" then "postgres" else "root";
+        default = "postgres";
         internal = true;
+        readOnly = true;
         description = ''
-          NixOS traditionally used 'root' as superuser, most other distros use 'postgres'.
-          From 17.09 we also try to follow this standard. Internal since changing this value
-          would lead to breakage while setting up databases.
+          PostgreSQL superuser account to use for various operations. Internal since changing
+          this value would lead to breakage while setting up databases.
         '';
         };
     };
@@ -240,6 +263,16 @@ in
 
   config = mkIf cfg.enable {
 
+    services.postgresql.settings =
+      {
+        hba_file = "${pkgs.writeText "pg_hba.conf" cfg.authentication}";
+        ident_file = "${pkgs.writeText "pg_ident.conf" cfg.identMap}";
+        log_destination = "stderr";
+        log_line_prefix = cfg.logLinePrefix;
+        listen_addresses = if cfg.enableTCPIP then "*" else "localhost";
+        port = cfg.port;
+      };
+
     services.postgresql.package =
       # Note: when changing the default, make it conditional on
       # ‘system.stateVersion’ to maintain compatibility with existing
@@ -249,10 +282,7 @@ in
             else if versionAtLeast config.system.stateVersion "16.03" then pkgs.postgresql_9_5
             else throw "postgresql_9_4 was removed, please upgrade your postgresql version.");
 
-    services.postgresql.dataDir =
-      mkDefault (if versionAtLeast config.system.stateVersion "17.09"
-                  then "/var/lib/postgresql/${cfg.package.psqlSchema}"
-                  else "/var/db/postgresql");
+    services.postgresql.dataDir = mkDefault "/var/lib/postgresql/${cfg.package.psqlSchema}";
 
     services.postgresql.authentication = mkAfter
       ''
@@ -291,59 +321,28 @@ in
 
         preStart =
           ''
-            # Create data directory.
             if ! test -e ${cfg.dataDir}/PG_VERSION; then
-              mkdir -m 0700 -p ${cfg.dataDir}
+              # Cleanup the data directory.
               rm -f ${cfg.dataDir}/*.conf
-              chown -R postgres:postgres ${cfg.dataDir}
-            fi
-          ''; # */
 
-        script =
-          ''
-            # Initialise the database.
-            if ! test -e ${cfg.dataDir}/PG_VERSION; then
+              # Initialise the database.
               initdb -U ${cfg.superUser} ${concatStringsSep " " cfg.initdbArgs}
+
               # See postStart!
               touch "${cfg.dataDir}/.first_startup"
             fi
+
             ln -sfn "${configFile}" "${cfg.dataDir}/postgresql.conf"
             ${optionalString (cfg.recoveryConfig != null) ''
               ln -sfn "${pkgs.writeText "recovery.conf" cfg.recoveryConfig}" \
                 "${cfg.dataDir}/recovery.conf"
             ''}
-            ${optionalString (!groupAccessAvailable) ''
-              # postgresql pre 11.0 doesn't start if state directory mode is group accessible
-              chmod 0700 "${cfg.dataDir}"
-            ''}
-
-            exec postgres
           '';
 
-        serviceConfig =
-          { ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
-            User = "postgres";
-            Group = "postgres";
-            PermissionsStartOnly = true;
-            RuntimeDirectory = "postgresql";
-            Type = if versionAtLeast cfg.package.version "9.6"
-                   then "notify"
-                   else "simple";
-
-            # Shut down Postgres using SIGINT ("Fast Shutdown mode").  See
-            # http://www.postgresql.org/docs/current/static/server-shutdown.html
-            KillSignal = "SIGINT";
-            KillMode = "mixed";
-
-            # Give Postgres a decent amount of time to clean up after
-            # receiving systemd's SIGINT.
-            TimeoutSec = 120;
-          };
-
         # Wait for PostgreSQL to be ready to accept connections.
         postStart =
           ''
-            PSQL="${pkgs.utillinux}/bin/runuser -u ${cfg.superUser} -- psql --port=${toString cfg.port}"
+            PSQL="psql --port=${toString cfg.port}"
 
             while ! $PSQL -d postgres -c "" 2> /dev/null; do
                 if ! kill -0 "$MAINPID"; then exit 1; fi
@@ -369,6 +368,32 @@ in
             '') cfg.ensureUsers}
           '';
 
+        serviceConfig = mkMerge [
+          { ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
+            User = "postgres";
+            Group = "postgres";
+            RuntimeDirectory = "postgresql";
+            Type = if versionAtLeast cfg.package.version "9.6"
+                   then "notify"
+                   else "simple";
+
+            # Shut down Postgres using SIGINT ("Fast Shutdown mode").  See
+            # http://www.postgresql.org/docs/current/static/server-shutdown.html
+            KillSignal = "SIGINT";
+            KillMode = "mixed";
+
+            # Give Postgres a decent amount of time to clean up after
+            # receiving systemd's SIGINT.
+            TimeoutSec = 120;
+
+            ExecStart = "${postgresql}/bin/postgres";
+          }
+          (mkIf (cfg.dataDir == "/var/lib/postgresql/${cfg.package.psqlSchema}") {
+            StateDirectory = "postgresql postgresql/${cfg.package.psqlSchema}";
+            StateDirectoryMode = if groupAccessAvailable then "0750" else "0700";
+          })
+        ];
+
         unitConfig.RequiresMountsFor = "${cfg.dataDir}";
       };
 
diff --git a/nixos/modules/services/databases/riak-cs.nix b/nixos/modules/services/databases/riak-cs.nix
index 2cb204f729a73..fa6ac88633185 100644
--- a/nixos/modules/services/databases/riak-cs.nix
+++ b/nixos/modules/services/databases/riak-cs.nix
@@ -35,7 +35,7 @@ in
           Name of the Erlang node.
         '';
       };
-      
+
       anonymousUserCreation = mkOption {
         type = types.bool;
         default = false;
diff --git a/nixos/modules/services/databases/victoriametrics.nix b/nixos/modules/services/databases/victoriametrics.nix
index cb6bf8508fb65..0af5d2adf3724 100644
--- a/nixos/modules/services/databases/victoriametrics.nix
+++ b/nixos/modules/services/databases/victoriametrics.nix
@@ -49,8 +49,8 @@ let cfg = config.services.victoriametrics; in
         ExecStart = ''
           ${cfg.package}/bin/victoria-metrics \
               -storageDataPath=/var/lib/victoriametrics \
-              -httpListenAddr ${cfg.listenAddress}
-              -retentionPeriod ${toString cfg.retentionPeriod}
+              -httpListenAddr ${cfg.listenAddress} \
+              -retentionPeriod ${toString cfg.retentionPeriod} \
               ${lib.escapeShellArgs cfg.extraOptions}
         '';
       };
diff --git a/nixos/modules/services/desktops/deepin/deepin.nix b/nixos/modules/services/desktops/deepin/deepin.nix
deleted file mode 100644
index f8fb73701af69..0000000000000
--- a/nixos/modules/services/desktops/deepin/deepin.nix
+++ /dev/null
@@ -1,123 +0,0 @@
-# deepin
-
-{ config, pkgs, lib, ... }:
-
-{
-
-  ###### interface
-
-  options = {
-
-    services.deepin.core.enable = lib.mkEnableOption "
-      Basic dbus and systemd services, groups and users needed by the
-      Deepin Desktop Environment.
-    ";
-
-    services.deepin.deepin-menu.enable = lib.mkEnableOption "
-      DBus service for unified menus in Deepin Desktop Environment.
-    ";
-
-    services.deepin.deepin-turbo.enable = lib.mkEnableOption "
-      Turbo service for the Deepin Desktop Environment. It is a daemon
-      that helps to launch applications faster.
-    ";
-
-  };
-
-
-  ###### implementation
-
-  config = lib.mkMerge [
-
-    (lib.mkIf config.services.deepin.core.enable {
-      environment.systemPackages = [
-        pkgs.deepin.dde-api
-        pkgs.deepin.dde-calendar
-        pkgs.deepin.dde-control-center
-        pkgs.deepin.dde-daemon
-        pkgs.deepin.dde-dock
-        pkgs.deepin.dde-launcher
-        pkgs.deepin.dde-file-manager
-        pkgs.deepin.dde-session-ui
-        pkgs.deepin.deepin-anything
-        pkgs.deepin.deepin-image-viewer
-      ];
-
-      services.dbus.packages = [
-        pkgs.deepin.dde-api
-        pkgs.deepin.dde-calendar
-        pkgs.deepin.dde-control-center
-        pkgs.deepin.dde-daemon
-        pkgs.deepin.dde-dock
-        pkgs.deepin.dde-launcher
-        pkgs.deepin.dde-file-manager
-        pkgs.deepin.dde-session-ui
-        pkgs.deepin.deepin-anything
-        pkgs.deepin.deepin-image-viewer
-      ];
-
-      systemd.packages = [
-        pkgs.deepin.dde-api
-        pkgs.deepin.dde-daemon
-        pkgs.deepin.dde-file-manager
-        pkgs.deepin.deepin-anything
-      ];
-
-      boot.extraModulePackages = [ config.boot.kernelPackages.deepin-anything ];
-
-      boot.kernelModules = [ "vfs_monitor" ];
-
-      users.groups.deepin-sound-player = { };
-
-      users.users.deepin-sound-player = {
-        description = "Deepin sound player";
-        group = "deepin-sound-player";
-        isSystemUser = true;
-      };
-
-      users.groups.deepin-daemon = { };
-
-      users.users.deepin-daemon = {
-        description = "Deepin daemon user";
-        group = "deepin-daemon";
-        isSystemUser = true;
-      };
-
-      users.groups.deepin_anything_server = { };
-
-      users.users.deepin_anything_server = {
-        description = "Deepin Anything Server";
-        group = "deepin_anything_server";
-        isSystemUser = true;
-      };
-
-      security.pam.services.deepin-auth-keyboard.text = ''
-        # original at ${pkgs.deepin.dde-daemon}/etc/pam.d/deepin-auth-keyboard
-        auth	[success=2 default=ignore]	pam_lsass.so
-        auth	[success=1 default=ignore]	pam_unix.so nullok_secure try_first_pass
-        auth	requisite	pam_deny.so
-        auth	required	pam_permit.so
-      '';
-
-      environment.etc = {
-        "polkit-1/localauthority/10-vendor.d/com.deepin.api.device.pkla".source = "${pkgs.deepin.dde-api}/etc/polkit-1/localauthority/10-vendor.d/com.deepin.api.device.pkla";
-        "polkit-1/localauthority/10-vendor.d/com.deepin.daemon.Accounts.pkla".source = "${pkgs.deepin.dde-daemon}/etc/polkit-1/localauthority/10-vendor.d/com.deepin.daemon.Accounts.pkla";
-        "polkit-1/localauthority/10-vendor.d/com.deepin.daemon.Grub2.pkla".source = "${pkgs.deepin.dde-daemon}/etc/polkit-1/localauthority/10-vendor.d/com.deepin.daemon.Grub2.pkla";
-      };
-
-      services.deepin.deepin-menu.enable = true;
-      services.deepin.deepin-turbo.enable = true;
-    })
-
-    (lib.mkIf config.services.deepin.deepin-menu.enable {
-      services.dbus.packages = [ pkgs.deepin.deepin-menu ];
-    })
-
-    (lib.mkIf config.services.deepin.deepin-turbo.enable {
-      environment.systemPackages = [ pkgs.deepin.deepin-turbo ];
-      systemd.packages = [ pkgs.deepin.deepin-turbo ];
-    })
-
-  ];
-
-}
diff --git a/nixos/modules/services/desktops/espanso.nix b/nixos/modules/services/desktops/espanso.nix
new file mode 100644
index 0000000000000..cd2eadf88168e
--- /dev/null
+++ b/nixos/modules/services/desktops/espanso.nix
@@ -0,0 +1,25 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+let cfg = config.services.espanso;
+in {
+  meta = { maintainers = with lib.maintainers; [ numkem ]; };
+
+  options = {
+    services.espanso = { enable = options.mkEnableOption "Espanso"; };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.user.services.espanso = {
+      description = "Espanso daemon";
+      path = with pkgs; [ espanso libnotify xclip ];
+      serviceConfig = {
+        ExecStart = "${pkgs.espanso}/bin/espanso daemon";
+        Restart = "on-failure";
+      };
+      wantedBy = [ "default.target" ];
+    };
+
+    environment.systemPackages = [ pkgs.espanso ];
+  };
+}
diff --git a/nixos/modules/services/desktops/flatpak.nix b/nixos/modules/services/desktops/flatpak.nix
index 7fb0024f37dc7..7da92cc9f2649 100644
--- a/nixos/modules/services/desktops/flatpak.nix
+++ b/nixos/modules/services/desktops/flatpak.nix
@@ -42,6 +42,7 @@ in {
     # It has been possible since https://github.com/flatpak/flatpak/releases/tag/1.3.2
     # to build a SELinux policy module.
 
+    # TODO: use sysusers.d
     users.users.flatpak = {
       description = "Flatpak system helper";
       group = "flatpak";
diff --git a/nixos/modules/services/desktops/geoclue2.nix b/nixos/modules/services/desktops/geoclue2.nix
index 542b2ead41040..6702bd395a03e 100644
--- a/nixos/modules/services/desktops/geoclue2.nix
+++ b/nixos/modules/services/desktops/geoclue2.nix
@@ -160,7 +160,7 @@ in
       };
 
       appConfig = mkOption {
-        type = types.loaOf appConfigModule;
+        type = types.attrsOf appConfigModule;
         default = {};
         example = literalExample ''
           "com.github.app" = {
diff --git a/nixos/modules/services/desktops/malcontent.nix b/nixos/modules/services/desktops/malcontent.nix
index 5d6912595b52d..1fbeb17e6aeb4 100644
--- a/nixos/modules/services/desktops/malcontent.nix
+++ b/nixos/modules/services/desktops/malcontent.nix
@@ -28,7 +28,10 @@ with lib;
       malcontent-ui
     ];
 
-    services.dbus.packages = [ pkgs.malcontent ];
+    services.dbus.packages = [
+      # D-Bus services are in `out`, not the default `bin` output that would be picked up by `makeDbusConf`.
+      pkgs.malcontent.out
+    ];
 
     services.accounts-daemon.enable = true;
 
diff --git a/nixos/modules/services/development/jupyter/default.nix b/nixos/modules/services/development/jupyter/default.nix
index e598b0186450b..6a5fd6b2940e8 100644
--- a/nixos/modules/services/development/jupyter/default.nix
+++ b/nixos/modules/services/development/jupyter/default.nix
@@ -6,10 +6,7 @@ let
 
   cfg = config.services.jupyter;
 
-  # NOTE: We don't use top-level jupyter because we don't
-  # want to pass in JUPYTER_PATH but use .environment instead,
-  # saving a rebuild.
-  package = pkgs.python3.pkgs.notebook;
+  package = cfg.package;
 
   kernels = (pkgs.jupyter-kernel.create  {
     definitions = if cfg.kernels != null
@@ -37,6 +34,27 @@ in {
       '';
     };
 
+    package = mkOption {
+      type = types.package;
+      # NOTE: We don't use top-level jupyter because we don't
+      # want to pass in JUPYTER_PATH but use .environment instead,
+      # saving a rebuild.
+      default = pkgs.python3.pkgs.notebook;
+      description = ''
+        Jupyter package to use.
+      '';
+    };
+
+    command = mkOption {
+      type = types.str;
+      default = "jupyter-notebook";
+      example = "jupyter-lab";
+      description = ''
+        Which command the service runs. Note that not all jupyter packages
+        have all commands, e.g. jupyter-lab isn't present in the default package.
+       '';
+    };
+
     port = mkOption {
       type = types.int;
       default = 8888;
@@ -157,7 +175,7 @@ in {
 
         serviceConfig = {
           Restart = "always";
-          ExecStart = ''${package}/bin/jupyter-notebook \
+          ExecStart = ''${package}/bin/${cfg.command} \
             --no-browser \
             --ip=${cfg.ip} \
             --port=${toString cfg.port} --port-retries 0 \
diff --git a/nixos/modules/services/development/jupyterhub/default.nix b/nixos/modules/services/development/jupyterhub/default.nix
new file mode 100644
index 0000000000000..f1dcab68b0002
--- /dev/null
+++ b/nixos/modules/services/development/jupyterhub/default.nix
@@ -0,0 +1,190 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.services.jupyterhub;
+
+  kernels = (pkgs.jupyter-kernel.create  {
+    definitions = if cfg.kernels != null
+      then cfg.kernels
+      else  pkgs.jupyter-kernel.default;
+  });
+
+  jupyterhubConfig = pkgs.writeText "jupyterhub_config.py" ''
+    c.JupyterHub.bind_url = "http://${cfg.host}:${toString cfg.port}"
+
+    c.JupyterHub.authenticator_class = "${cfg.authentication}"
+    c.JupyterHub.spawner_class = "${cfg.spawner}"
+
+    c.SystemdSpawner.default_url = '/lab'
+    c.SystemdSpawner.cmd = "${cfg.jupyterlabEnv}/bin/jupyterhub-singleuser"
+    c.SystemdSpawner.environment = {
+      'JUPYTER_PATH': '${kernels}'
+    }
+
+    ${cfg.extraConfig}
+  '';
+in {
+  meta.maintainers = with maintainers; [ costrouc ];
+
+  options.services.jupyterhub = {
+    enable = mkEnableOption "Jupyterhub development server";
+
+    authentication = mkOption {
+      type = types.str;
+      default = "jupyterhub.auth.PAMAuthenticator";
+      description = ''
+        Jupyterhub authentication to use
+
+        There are many authenticators available including: oauth, pam,
+        ldap, kerberos, etc.
+      '';
+    };
+
+    spawner = mkOption {
+      type = types.str;
+      default = "systemdspawner.SystemdSpawner";
+      description = ''
+        Jupyterhub spawner to use
+
+        There are many spawners available including: local process,
+        systemd, docker, kubernetes, yarn, batch, etc.
+      '';
+    };
+
+    extraConfig = mkOption {
+      type = types.lines;
+      default = "";
+      description = ''
+        Extra contents appended to the jupyterhub configuration
+
+        Jupyterhub configuration is a normal python file using
+        Traitlets. https://jupyterhub.readthedocs.io/en/stable/getting-started/config-basics.html. The
+        base configuration of this module was designed to have sane
+        defaults for configuration but you can override anything since
+        this is a python file.
+      '';
+      example = literalExample ''
+         c.SystemdSpawner.mem_limit = '8G'
+         c.SystemdSpawner.cpu_limit = 2.0
+      '';
+    };
+
+    jupyterhubEnv = mkOption {
+      type = types.package;
+      default = (pkgs.python3.withPackages (p: with p; [
+        jupyterhub
+        jupyterhub-systemdspawner
+      ]));
+      description = ''
+        Python environment to run jupyterhub
+
+        Customizing will affect the packages available in the hub and
+        proxy. This will allow packages to be available for the
+        extraConfig that you may need. This will not normally need to
+        be changed.
+      '';
+    };
+
+    jupyterlabEnv = mkOption {
+      type = types.package;
+      default = (pkgs.python3.withPackages (p: with p; [
+        jupyterhub
+        jupyterlab
+      ]));
+      description = ''
+        Python environment to run jupyterlab
+
+        Customizing will affect the packages available in the
+        jupyterlab server and the default kernel provided. This is the
+        way to customize the jupyterlab extensions and jupyter
+        notebook extensions. This will not normally need to
+        be changed.
+      '';
+    };
+
+    kernels = mkOption {
+      type = types.nullOr (types.attrsOf(types.submodule (import ../jupyter/kernel-options.nix {
+        inherit lib;
+      })));
+
+      default = null;
+      example = literalExample ''
+        {
+          python3 = let
+            env = (pkgs.python3.withPackages (pythonPackages: with pythonPackages; [
+                    ipykernel
+                    pandas
+                    scikitlearn
+                  ]));
+          in {
+            displayName = "Python 3 for machine learning";
+            argv = [
+              "''${env.interpreter}"
+              "-m"
+              "ipykernel_launcher"
+              "-f"
+              "{connection_file}"
+            ];
+            language = "python";
+            logo32 = "''${env}/''${env.sitePackages}/ipykernel/resources/logo-32x32.png";
+            logo64 = "''${env}/''${env.sitePackages}/ipykernel/resources/logo-64x64.png";
+          };
+        }
+      '';
+      description = ''
+        Declarative kernel config
+
+        Kernels can be declared in any language that supports and has
+        the required dependencies to communicate with a jupyter server.
+        In python's case, it means that ipykernel package must always be
+        included in the list of packages of the targeted environment.
+      '';
+    };
+
+    port = mkOption {
+      type = types.port;
+      default = 8000;
+      description = ''
+        Port number Jupyterhub will be listening on
+      '';
+    };
+
+    host = mkOption {
+      type = types.str;
+      default = "0.0.0.0";
+      description = ''
+        Bind IP JupyterHub will be listening on
+      '';
+    };
+
+    stateDirectory = mkOption {
+      type = types.str;
+      default = "jupyterhub";
+      description = ''
+        Directory for jupyterhub state (token + database)
+      '';
+    };
+  };
+
+  config = mkMerge [
+    (mkIf cfg.enable  {
+      systemd.services.jupyterhub = {
+        description = "Jupyterhub development server";
+
+        after = [ "network.target" ];
+        wantedBy = [ "multi-user.target" ];
+
+        serviceConfig = {
+          Restart = "always";
+          ExecStart = "${cfg.jupyterhubEnv}/bin/jupyterhub --config ${jupyterhubConfig}";
+          User = "root";
+          StateDirectory = cfg.stateDirectory;
+          WorkingDirectory = "/var/lib/${cfg.stateDirectory}";
+        };
+      };
+    })
+  ];
+}
diff --git a/nixos/modules/services/development/lorri.nix b/nixos/modules/services/development/lorri.nix
index c843aa56d133c..fc576e4c18ba8 100644
--- a/nixos/modules/services/development/lorri.nix
+++ b/nixos/modules/services/development/lorri.nix
@@ -15,6 +15,15 @@ in {
           issued by the `lorri` command.
         '';
       };
+      package = lib.mkOption {
+        default = pkgs.lorri;
+        type = lib.types.package;
+        description = ''
+          The lorri package to use.
+        '';
+        defaultText = lib.literalExample "pkgs.lorri";
+        example = lib.literalExample "pkgs.lorri";
+      };
     };
   };
 
@@ -34,7 +43,7 @@ in {
       after = [ "lorri.socket" ];
       path = with pkgs; [ config.nix.package git gnutar gzip ];
       serviceConfig = {
-        ExecStart = "${pkgs.lorri}/bin/lorri daemon";
+        ExecStart = "${cfg.package}/bin/lorri daemon";
         PrivateTmp = true;
         ProtectSystem = "strict";
         ProtectHome = "read-only";
@@ -42,6 +51,6 @@ in {
       };
     };
 
-    environment.systemPackages = [ pkgs.lorri ];
+    environment.systemPackages = [ cfg.package ];
   };
 }
diff --git a/nixos/modules/services/editors/emacs.nix b/nixos/modules/services/editors/emacs.nix
index d791b387665fc..00d9eaad9eb9f 100644
--- a/nixos/modules/services/editors/emacs.nix
+++ b/nixos/modules/services/editors/emacs.nix
@@ -15,26 +15,27 @@ let
     fi
   '';
 
-desktopApplicationFile = pkgs.writeTextFile {
-  name = "emacsclient.desktop";
-  destination = "/share/applications/emacsclient.desktop";
-  text = ''
-[Desktop Entry]
-Name=Emacsclient
-GenericName=Text Editor
-Comment=Edit text
-MimeType=text/english;text/plain;text/x-makefile;text/x-c++hdr;text/x-c++src;text/x-chdr;text/x-csrc;text/x-java;text/x-moc;text/x-pascal;text/x-tcl;text/x-tex;application/x-shellscript;text/x-c;text/x-c++;
-Exec=emacseditor %F
-Icon=emacs
-Type=Application
-Terminal=false
-Categories=Development;TextEditor;
-StartupWMClass=Emacs
-Keywords=Text;Editor;
-'';
-};
-
-in {
+  desktopApplicationFile = pkgs.writeTextFile {
+    name = "emacsclient.desktop";
+    destination = "/share/applications/emacsclient.desktop";
+    text = ''
+      [Desktop Entry]
+      Name=Emacsclient
+      GenericName=Text Editor
+      Comment=Edit text
+      MimeType=text/english;text/plain;text/x-makefile;text/x-c++hdr;text/x-c++src;text/x-chdr;text/x-csrc;text/x-java;text/x-moc;text/x-pascal;text/x-tcl;text/x-tex;application/x-shellscript;text/x-c;text/x-c++;
+      Exec=emacseditor %F
+      Icon=emacs
+      Type=Application
+      Terminal=false
+      Categories=Development;TextEditor;
+      StartupWMClass=Emacs
+      Keywords=Text;Editor;
+    '';
+  };
+
+in
+{
 
   options.services.emacs = {
     enable = mkOption {
@@ -86,10 +87,10 @@ in {
       description = "Emacs: the extensible, self-documenting text editor";
 
       serviceConfig = {
-        Type      = "forking";
+        Type = "forking";
         ExecStart = "${pkgs.bash}/bin/bash -c 'source ${config.system.build.setEnvironment}; exec ${cfg.package}/bin/emacs --daemon'";
-        ExecStop  = "${cfg.package}/bin/emacsclient --eval (kill-emacs)";
-        Restart   = "always";
+        ExecStop = "${cfg.package}/bin/emacsclient --eval (kill-emacs)";
+        Restart = "always";
       };
     } // optionalAttrs cfg.enable { wantedBy = [ "default.target" ]; };
 
diff --git a/nixos/modules/services/editors/emacs.xml b/nixos/modules/services/editors/emacs.xml
index 74c60014dcea0..302aa1ed7c482 100644
--- a/nixos/modules/services/editors/emacs.xml
+++ b/nixos/modules/services/editors/emacs.xml
@@ -53,11 +53,11 @@
        <varname>emacs</varname>
       </term>
       <term>
-       <varname>emacs25</varname>
+       <varname>emacs</varname>
       </term>
       <listitem>
        <para>
-        The latest stable version of Emacs 25 using the
+        The latest stable version of Emacs using the
         <link
                 xlink:href="http://www.gtk.org">GTK 2</link>
         widget toolkit.
@@ -66,11 +66,11 @@
      </varlistentry>
      <varlistentry>
       <term>
-       <varname>emacs25-nox</varname>
+       <varname>emacs-nox</varname>
       </term>
       <listitem>
        <para>
-        Emacs 25 built without any dependency on X11 libraries.
+        Emacs built without any dependency on X11 libraries.
        </para>
       </listitem>
      </varlistentry>
@@ -79,11 +79,11 @@
        <varname>emacsMacport</varname>
       </term>
       <term>
-       <varname>emacs25Macport</varname>
+       <varname>emacsMacport</varname>
       </term>
       <listitem>
        <para>
-        Emacs 25 with the "Mac port" patches, providing a more native look and
+        Emacs with the "Mac port" patches, providing a more native look and
         feel under macOS.
        </para>
       </listitem>
@@ -322,7 +322,7 @@ https://nixos.org/nixpkgs/manual/#sec-modify-via-packageOverrides
     If you want, you can tweak the Emacs package itself from your
     <filename>emacs.nix</filename>. For example, if you want to have a
     GTK 3-based Emacs instead of the default GTK 2-based binary and remove the
-    automatically generated <filename>emacs.desktop</filename> (useful is you
+    automatically generated <filename>emacs.desktop</filename> (useful if you
     only use <command>emacsclient</command>), you can change your file
     <filename>emacs.nix</filename> in this way:
    </para>
diff --git a/nixos/modules/services/games/minetest-server.nix b/nixos/modules/services/games/minetest-server.nix
index 98e69c6dc0ea6..f52079fc1ef62 100644
--- a/nixos/modules/services/games/minetest-server.nix
+++ b/nixos/modules/services/games/minetest-server.nix
@@ -5,12 +5,12 @@ with lib;
 let
   cfg   = config.services.minetest-server;
   flag  = val: name: if val != null then "--${name} ${val} " else "";
-  flags = [ 
-    (flag cfg.gameId "gameid") 
-    (flag cfg.world "world") 
-    (flag cfg.configPath "config") 
-    (flag cfg.logPath "logfile") 
-    (flag cfg.port "port") 
+  flags = [
+    (flag cfg.gameId "gameid")
+    (flag cfg.world "world")
+    (flag cfg.configPath "config")
+    (flag cfg.logPath "logfile")
+    (flag cfg.port "port")
   ];
 in
 {
@@ -26,7 +26,7 @@ in
         type        = types.nullOr types.str;
         default     = null;
         description = ''
-          Id of the game to use. To list available games run 
+          Id of the game to use. To list available games run
           `minetestserver --gameid list`.
 
           If only one game exists, this option can be null.
@@ -59,7 +59,7 @@ in
         type        = types.nullOr types.path;
         default     = null;
         description = ''
-          Path to logfile for logging. 
+          Path to logfile for logging.
 
           If set to null, logging will be output to stdout which means
           all output will be catched by systemd.
diff --git a/nixos/modules/services/games/terraria.nix b/nixos/modules/services/games/terraria.nix
index a59b74c0b4c4b..34c8ff137d6a2 100644
--- a/nixos/modules/services/games/terraria.nix
+++ b/nixos/modules/services/games/terraria.nix
@@ -7,7 +7,7 @@ let
   worldSizeMap = { small = 1; medium = 2; large = 3; };
   valFlag = name: val: optionalString (val != null) "-${name} \"${escape ["\\" "\""] (toString val)}\"";
   boolFlag = name: val: optionalString val "-${name}";
-  flags = [ 
+  flags = [
     (valFlag "port" cfg.port)
     (valFlag "maxPlayers" cfg.maxPlayers)
     (valFlag "password" cfg.password)
@@ -25,7 +25,7 @@ let
       exit 0
     fi
 
-    ${getBin pkgs.tmux}/bin/tmux -S /var/lib/terraria/terraria.sock send-keys Enter exit Enter
+    ${getBin pkgs.tmux}/bin/tmux -S ${cfg.dataDir}/terraria.sock send-keys Enter exit Enter
     ${getBin pkgs.coreutils}/bin/tail --pid="$1" -f /dev/null
   '';
 in
@@ -36,7 +36,7 @@ in
         type        = types.bool;
         default     = false;
         description = ''
-          If enabled, starts a Terraria server. The server can be connected to via <literal>tmux -S /var/lib/terraria/terraria.sock attach</literal>
+          If enabled, starts a Terraria server. The server can be connected to via <literal>tmux -S ${cfg.dataDir}/terraria.sock attach</literal>
           for administration by users who are a part of the <literal>terraria</literal> group (use <literal>C-b d</literal> shortcut to detach again).
         '';
       };
@@ -111,13 +111,19 @@ in
         default     = false;
         description = "Disables automatic Universal Plug and Play.";
       };
+      dataDir = mkOption {
+        type        = types.str;
+        default     = "/var/lib/terraria";
+        example     = "/srv/terraria";
+        description = "Path to variable state data directory for terraria.";
+      };
     };
   };
 
   config = mkIf cfg.enable {
     users.users.terraria = {
       description = "Terraria server service user";
-      home        = "/var/lib/terraria";
+      home        = cfg.dataDir;
       createHome  = true;
       uid         = config.ids.uids.terraria;
     };
@@ -136,13 +142,13 @@ in
         User    = "terraria";
         Type = "forking";
         GuessMainPID = true;
-        ExecStart = "${getBin pkgs.tmux}/bin/tmux -S /var/lib/terraria/terraria.sock new -d ${pkgs.terraria-server}/bin/TerrariaServer ${concatStringsSep " " flags}";
+        ExecStart = "${getBin pkgs.tmux}/bin/tmux -S ${cfg.dataDir}/terraria.sock new -d ${pkgs.terraria-server}/bin/TerrariaServer ${concatStringsSep " " flags}";
         ExecStop = "${stopScript} $MAINPID";
       };
 
       postStart = ''
-        ${pkgs.coreutils}/bin/chmod 660 /var/lib/terraria/terraria.sock
-        ${pkgs.coreutils}/bin/chgrp terraria /var/lib/terraria/terraria.sock
+        ${pkgs.coreutils}/bin/chmod 660 ${cfg.dataDir}/terraria.sock
+        ${pkgs.coreutils}/bin/chgrp terraria ${cfg.dataDir}/terraria.sock
       '';
     };
   };
diff --git a/nixos/modules/services/hardware/fancontrol.nix b/nixos/modules/services/hardware/fancontrol.nix
index bb4541a784dae..e1ce11a5aef62 100644
--- a/nixos/modules/services/hardware/fancontrol.nix
+++ b/nixos/modules/services/hardware/fancontrol.nix
@@ -12,7 +12,7 @@ in{
 
     config = mkOption {
       default = null;
-      type = types.lines;
+      type = types.nullOr types.lines;
       description = "Fancontrol configuration file content. See <citerefentry><refentrytitle>pwmconfig</refentrytitle><manvolnum>8</manvolnum></citerefentry> from the lm_sensors package.";
       example = ''
         # Configuration file generated by pwmconfig
diff --git a/nixos/modules/services/hardware/sane_extra_backends/brscan4.nix b/nixos/modules/services/hardware/sane_extra_backends/brscan4.nix
index 6f49a1ab6d406..a6afa01dd8124 100644
--- a/nixos/modules/services/hardware/sane_extra_backends/brscan4.nix
+++ b/nixos/modules/services/hardware/sane_extra_backends/brscan4.nix
@@ -81,7 +81,7 @@ in
         { office1 = { model = "MFC-7860DW"; ip = "192.168.1.2"; };
           office2 = { model = "MFC-7860DW"; nodename = "BRW0080927AFBCE"; };
         };
-      type = with types; loaOf (submodule netDeviceOpts);
+      type = with types; attrsOf (submodule netDeviceOpts);
       description = ''
         The list of network devices that will be registered against the brscan4
         sane backend.
diff --git a/nixos/modules/services/hardware/thermald.nix b/nixos/modules/services/hardware/thermald.nix
index ecb529e9bf018..b7be0e89d0c66 100644
--- a/nixos/modules/services/hardware/thermald.nix
+++ b/nixos/modules/services/hardware/thermald.nix
@@ -23,6 +23,15 @@ in {
         default = null;
         description = "the thermald manual configuration file.";
       };
+
+      adaptive = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to enable adaptive mode, only working on kernel versions greater than 5.8.
+          Thermald will detect this itself, safe to enable on kernel versions below 5.8.
+        '';
+      };
     };
   };
 
@@ -39,6 +48,7 @@ in {
             --no-daemon \
             ${optionalString cfg.debug "--loglevel=debug"} \
             ${optionalString (cfg.configFile != null) "--config-file ${cfg.configFile}"} \
+            ${optionalString cfg.adaptive "--adaptive"} \
             --dbus-enable
         '';
       };
diff --git a/nixos/modules/services/hardware/thinkfan.nix b/nixos/modules/services/hardware/thinkfan.nix
index 7c105e99ca54a..3bda61ed1a938 100644
--- a/nixos/modules/services/hardware/thinkfan.nix
+++ b/nixos/modules/services/hardware/thinkfan.nix
@@ -67,7 +67,7 @@ in {
         type = types.bool;
         default = false;
         description = ''
-          Whether to build thinkfan with SMART support to read temperatures 
+          Whether to build thinkfan with SMART support to read temperatures
           directly from hard disks.
         '';
       };
diff --git a/nixos/modules/services/hardware/tlp.nix b/nixos/modules/services/hardware/tlp.nix
index 3962d7b159894..4230f2edd2793 100644
--- a/nixos/modules/services/hardware/tlp.nix
+++ b/nixos/modules/services/hardware/tlp.nix
@@ -8,12 +8,8 @@ let
   mkTlpConfig = tlpConfig: generators.toKeyValue {
     mkKeyValue = generators.mkKeyValueDefault {
       mkValueString = val:
-        if isInt val then toString val
-        else if isString val then val
-        else if true == val then "1"
-        else if false == val then "0"
-        else if isList val then "\"" + (concatStringsSep " " val) + "\""
-        else err "invalid value provided to mkTlpConfig:" (toString val);
+        if isList val then "\"" + (toString val) + "\""
+        else toString val;
     } "=";
   } tlpConfig;
 in
@@ -27,10 +23,24 @@ in
         description = "Whether to enable the TLP power management daemon.";
       };
 
+      settings = mkOption {type = with types; attrsOf (oneOf [bool int float str (listOf str)]);
+        default = {};
+        example = {
+          SATA_LINKPWR_ON_BAT = "med_power_with_dipm";
+          USB_BLACKLIST_PHONE = 1;
+        };
+        description = ''
+          Options passed to TLP. See https://linrunner.de/tlp for all supported options..
+        '';
+      };
+
       extraConfig = mkOption {
         type = types.lines;
         default = "";
-        description = "Additional configuration variables for TLP";
+        description = ''
+          Verbatim additional configuration variables for TLP.
+          DEPRECATED: use services.tlp.config instead.
+        '';
       };
     };
   };
@@ -39,8 +49,20 @@ in
   config = mkIf cfg.enable {
     boot.kernelModules = [ "msr" ];
 
+    warnings = optional (cfg.extraConfig != "") ''
+      Using config.services.tlp.extraConfig is deprecated and will become unsupported in a future release. Use config.services.tlp.settings instead.
+    '';
+
+    assertions = [{
+      assertion = cfg.enable -> config.powerManagement.scsiLinkPolicy == null;
+      message = ''
+        `services.tlp.enable` and `config.powerManagement.scsiLinkPolicy` cannot be set both.
+        Set `services.tlp.settings.SATA_LINKPWR_ON_AC` and `services.tlp.settings.SATA_LINKPWR_ON_BAT` instead.
+      '';
+    }];
+
     environment.etc = {
-      "tlp.conf".text = cfg.extraConfig;
+      "tlp.conf".text = (mkTlpConfig cfg.settings) + cfg.extraConfig;
     } // optionalAttrs enableRDW {
       "NetworkManager/dispatcher.d/99tlp-rdw-nm".source =
         "${tlp}/etc/NetworkManager/dispatcher.d/99tlp-rdw-nm";
@@ -48,18 +70,25 @@ in
 
     environment.systemPackages = [ tlp ];
 
-    # FIXME: When the config is parametrized we need to move these into a
-    # conditional on the relevant options being enabled.
-    powerManagement = {
-      scsiLinkPolicy = null;
-      cpuFreqGovernor = null;
-      cpufreq.max = null;
-      cpufreq.min = null;
+
+    services.tlp.settings = let
+      cfg = config.powerManagement;
+      maybeDefault = val: lib.mkIf (val != null) (lib.mkDefault val);
+    in {
+      CPU_SCALING_GOVERNOR_ON_AC = maybeDefault cfg.cpuFreqGovernor;
+      CPU_SCALING_GOVERNOR_ON_BAT = maybeDefault cfg.cpuFreqGovernor;
+      CPU_SCALING_MIN_FREQ_ON_AC = maybeDefault cfg.cpufreq.min;
+      CPU_SCALING_MAX_FREQ_ON_AC = maybeDefault cfg.cpufreq.max;
+      CPU_SCALING_MIN_FREQ_ON_BAT = maybeDefault cfg.cpufreq.min;
+      CPU_SCALING_MAX_FREQ_ON_BAT = maybeDefault cfg.cpufreq.max;
     };
 
     services.udev.packages = [ tlp ];
 
     systemd = {
+      # use native tlp instead because it can also differentiate between AC/BAT
+      services.cpufreq.enable = false;
+
       packages = [ tlp ];
       # XXX: These must always be disabled/masked according to [1].
       #
diff --git a/nixos/modules/services/hardware/trezord.nix b/nixos/modules/services/hardware/trezord.nix
index c517e9fbb2bda..2594ac7437109 100644
--- a/nixos/modules/services/hardware/trezord.nix
+++ b/nixos/modules/services/hardware/trezord.nix
@@ -10,7 +10,7 @@ in {
   meta = {
     doc = ./trezord.xml;
   };
-  
+
   ### interface
 
   options = {
@@ -40,7 +40,7 @@ in {
       };
     };
   };
-  
+
   ### implementation
 
   config = mkIf cfg.enable {
diff --git a/nixos/modules/services/hardware/undervolt.nix b/nixos/modules/services/hardware/undervolt.nix
index da627af73bc68..054ffa35050a9 100644
--- a/nixos/modules/services/hardware/undervolt.nix
+++ b/nixos/modules/services/hardware/undervolt.nix
@@ -25,8 +25,11 @@ let
 in
 {
   options.services.undervolt = {
-    enable = mkEnableOption
-      "Intel CPU undervolting service (WARNING: may permanently damage your hardware!)";
+    enable = mkEnableOption ''
+       Undervolting service for Intel CPUs.
+
+       Warning: This service is not endorsed by Intel and may permanently damage your hardware. Use at your own risk!
+    '';
 
     verbose = mkOption {
       type = types.bool;
@@ -100,6 +103,17 @@ in
         The temperature target on battery power in Celsius degrees.
       '';
     };
+
+    useTimer = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Whether to set a timer that applies the undervolt settings every 30s.
+        This will cause spam in the journal but might be required for some
+        hardware under specific conditions.
+        Enable this if your undervolt settings don't hold.
+      '';
+    };
   };
 
   config = mkIf cfg.enable {
@@ -111,6 +125,11 @@ in
       path = [ pkgs.undervolt ];
 
       description = "Intel Undervolting Service";
+
+      # Apply undervolt on boot, nixos generation switch and resume
+      wantedBy = [ "multi-user.target" "post-resume.target" ];
+      after = [ "post-resume.target" ]; # Not sure why but it won't work without this
+
       serviceConfig = {
         Type = "oneshot";
         Restart = "no";
@@ -118,7 +137,7 @@ in
       };
     };
 
-    systemd.timers.undervolt = {
+    systemd.timers.undervolt = mkIf cfg.useTimer {
       description = "Undervolt timer to ensure voltage settings are always applied";
       partOf = [ "undervolt.service" ];
       wantedBy = [ "multi-user.target" ];
diff --git a/nixos/modules/services/logging/logrotate.nix b/nixos/modules/services/logging/logrotate.nix
index 565618b27a87b..7d6102b82557e 100644
--- a/nixos/modules/services/logging/logrotate.nix
+++ b/nixos/modules/services/logging/logrotate.nix
@@ -5,54 +5,93 @@ with lib;
 let
   cfg = config.services.logrotate;
 
-  pathOptions = {
+  pathOpts = {
     options = {
+      enable = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          Whether to enable log rotation for this path. This can be used to explicitly disable
+          logging that has been configured by NixOS.
+        '';
+      };
+
       path = mkOption {
         type = types.str;
-        description = "The path to log files to be rotated";
+        description = ''
+          The path to log files to be rotated.
+        '';
       };
+
       user = mkOption {
-        type = types.str;
-        description = "The user account to use for rotation";
+        type = with types; nullOr str;
+        default = null;
+        description = ''
+          The user account to use for rotation.
+        '';
       };
+
       group = mkOption {
-        type = types.str;
-        description = "The group to use for rotation";
+        type = with types; nullOr str;
+        default = null;
+        description = ''
+          The group to use for rotation.
+        '';
       };
+
       frequency = mkOption {
-        type = types.enum [
-          "daily" "weekly" "monthly" "yearly"
-        ];
+        type = types.enum [ "daily" "weekly" "monthly" "yearly" ];
         default = "daily";
-        description = "How often to rotate the logs";
+        description = ''
+          How often to rotate the logs.
+        '';
       };
+
       keep = mkOption {
         type = types.int;
         default = 20;
-        description = "How many rotations to keep";
+        description = ''
+          How many rotations to keep.
+        '';
       };
+
       extraConfig = mkOption {
         type = types.lines;
         default = "";
-        description = "Extra logrotate config options for this path";
+        description = ''
+          Extra logrotate config options for this path. Refer to
+          <link xlink:href="https://linux.die.net/man/8/logrotate"/> for details.
+        '';
+      };
+
+      priority = mkOption {
+        type = types.int;
+        default = 1000;
+        description = ''
+          Order of this logrotate block in relation to the others. The semantics are
+          the same as with `lib.mkOrder`. Smaller values have a greater priority.
+        '';
       };
     };
-  };
 
-  pathConfig = options: ''
-    "${options.path}" {
-      su ${options.user} ${options.group}
-      ${options.frequency}
+    config.extraConfig = ''
       missingok
       notifempty
-      rotate ${toString options.keep}
-      ${options.extraConfig}
+    '';
+  };
+
+  mkConf = pathOpts: ''
+    # generated by NixOS using the `services.logrotate.paths.${pathOpts.name}` attribute set
+    "${pathOpts.path}" {
+      ${optionalString (pathOpts.user != null || pathOpts.group != null) "su ${pathOpts.user} ${pathOpts.group}"}
+      ${pathOpts.frequency}
+      rotate ${toString pathOpts.keep}
+      ${pathOpts.extraConfig}
     }
   '';
 
-  configFile = pkgs.writeText "logrotate.conf" (
-    (concatStringsSep "\n" ((map pathConfig cfg.paths) ++ [cfg.extraConfig]))
-  );
+  paths = sortProperties (mapAttrsToList (name: pathOpts: pathOpts // { name = name; }) (filterAttrs (_: pathOpts: pathOpts.enable) cfg.paths));
+  configFile = pkgs.writeText "logrotate.conf" (concatStringsSep "\n" ((map mkConf paths) ++ [ cfg.extraConfig ]));
 
 in
 {
@@ -65,41 +104,66 @@ in
       enable = mkEnableOption "the logrotate systemd service";
 
       paths = mkOption {
-        type = types.listOf (types.submodule pathOptions);
-        default = [];
-        description = "List of attribute sets with paths to rotate";
-        example = {
-          "/var/log/myapp/*.log" = {
-            user = "myuser";
-            group = "mygroup";
-            rotate = "weekly";
-            keep = 5;
-          };
-        };
+        type = with types; attrsOf (submodule pathOpts);
+        default = {};
+        description = ''
+          Attribute set of paths to rotate. The order each block appears in the generated configuration file
+          can be controlled by the <link linkend="opt-services.logrotate.paths._name_.priority">priority</link> option
+          using the same semantics as `lib.mkOrder`. Smaller values have a greater priority.
+        '';
+        example = literalExample ''
+          {
+            httpd = {
+              path = "/var/log/httpd/*.log";
+              user = config.services.httpd.user;
+              group = config.services.httpd.group;
+              keep = 7;
+            };
+
+            myapp = {
+              path = "/var/log/myapp/*.log";
+              user = "myuser";
+              group = "mygroup";
+              frequency = "weekly";
+              keep = 5;
+              priority = 1;
+            };
+          }
+        '';
       };
 
       extraConfig = mkOption {
         default = "";
         type = types.lines;
         description = ''
-          Extra contents to add to the logrotate config file.
-          See https://linux.die.net/man/8/logrotate
+          Extra contents to append to the logrotate configuration file. Refer to
+          <link xlink:href="https://linux.die.net/man/8/logrotate"/> for details.
         '';
       };
     };
   };
 
   config = mkIf cfg.enable {
-    systemd.services.logrotate = {
-      description   = "Logrotate Service";
-      wantedBy      = [ "multi-user.target" ];
-      startAt       = "*-*-* *:05:00";
+    assertions = mapAttrsToList (name: pathOpts:
+      { assertion = (pathOpts.user != null) == (pathOpts.group != null);
+        message = ''
+          If either of `services.logrotate.paths.${name}.user` or `services.logrotate.paths.${name}.group` are specified then *both* must be specified.
+        '';
+      }
+    ) cfg.paths;
 
-      serviceConfig.Restart = "no";
-      serviceConfig.User    = "root";
+    systemd.services.logrotate = {
+      description = "Logrotate Service";
+      wantedBy = [ "multi-user.target" ];
+      startAt = "*-*-* *:05:00";
       script = ''
         exec ${pkgs.logrotate}/sbin/logrotate ${configFile}
       '';
+
+      serviceConfig = {
+        Restart = "no";
+        User = "root";
+      };
     };
   };
 }
diff --git a/nixos/modules/services/logging/logstash.nix b/nixos/modules/services/logging/logstash.nix
index 21a83803fd8c6..bf92425f998bb 100644
--- a/nixos/modules/services/logging/logstash.nix
+++ b/nixos/modules/services/logging/logstash.nix
@@ -4,13 +4,9 @@ with lib;
 
 let
   cfg = config.services.logstash;
-  pluginPath = lib.concatStringsSep ":" cfg.plugins;
-  havePluginPath = lib.length cfg.plugins > 0;
   ops = lib.optionalString;
   verbosityFlag = "--log.level " + cfg.logLevel;
 
-  pluginsPath = "--path.plugins ${pluginPath}";
-
   logstashConf = pkgs.writeText "logstash.conf" ''
     input {
       ${cfg.inputConfig}
@@ -173,7 +169,7 @@ in
         ExecStart = concatStringsSep " " (filter (s: stringLength s != 0) [
           "${cfg.package}/bin/logstash"
           "-w ${toString cfg.filterWorkers}"
-          (ops havePluginPath pluginsPath)
+          (concatMapStringsSep " " (x: "--path.plugins ${x}") cfg.plugins)
           "${verbosityFlag}"
           "-f ${logstashConf}"
           "--path.settings ${logstashSettingsDir}"
diff --git a/nixos/modules/services/mail/dovecot.nix b/nixos/modules/services/mail/dovecot.nix
index 51cbcbf1cbc8a..c166ef68f2929 100644
--- a/nixos/modules/services/mail/dovecot.nix
+++ b/nixos/modules/services/mail/dovecot.nix
@@ -1,4 +1,4 @@
-{ config, lib, pkgs, ... }:
+{ options, config, lib, pkgs, ... }:
 
 with lib;
 
@@ -83,11 +83,11 @@ let
     )
 
     (
-      optionalString (cfg.mailboxes != []) ''
+      optionalString (cfg.mailboxes != {}) ''
         protocol imap {
           namespace inbox {
             inbox=yes
-            ${concatStringsSep "\n" (map mailboxConfig cfg.mailboxes)}
+            ${concatStringsSep "\n" (map mailboxConfig (attrValues cfg.mailboxes))}
           }
         }
       ''
@@ -131,12 +131,13 @@ let
     special_use = \${toString mailbox.specialUse}
   '' + "}";
 
-  mailboxes = { ... }: {
+  mailboxes = { name, ... }: {
     options = {
       name = mkOption {
-        type = types.nullOr (types.strMatching ''[^"]+'');
+        type = types.strMatching ''[^"]+'';
         example = "Spam";
-        default = null;
+        default = name;
+        readOnly = true;
         description = "The name of the mailbox.";
       };
       auto = mkOption {
@@ -335,19 +336,11 @@ in
     };
 
     mailboxes = mkOption {
-      type = with types; let m = submodule mailboxes; in either (listOf m) (attrsOf m);
+      type = with types; coercedTo
+        (listOf unspecified)
+        (list: listToAttrs (map (entry: { name = entry.name; value = removeAttrs entry ["name"]; }) list))
+        (attrsOf (submodule mailboxes));
       default = {};
-      apply = x:
-        if isList x then warn "Declaring `services.dovecot2.mailboxes' as a list is deprecated and will break eval in 21.03!" x
-        else mapAttrsToList (name: value:
-          if value.name != null
-            then throw ''
-              When specifying dovecot2 mailboxes as attributes, declaring
-              a `name'-attribute is prohibited! The name ${value.name} should
-              be the attribute key!
-            ''
-          else value // { inherit name; }
-        ) x;
       example = literalExample ''
         {
           Spam = { specialUse = "Junk"; auto = "create"; };
@@ -471,6 +464,10 @@ in
 
     environment.systemPackages = [ dovecotPkg ];
 
+    warnings = mkIf (any isList options.services.dovecot2.mailboxes.definitions) [
+      "Declaring `services.dovecot2.mailboxes' as a list is deprecated and will break eval in 21.03! See the release notes for more info for migration."
+    ];
+
     assertions = [
       {
         assertion = intersectLists cfg.protocols [ "pop3" "imap" ] != [];
diff --git a/nixos/modules/services/mail/mailhog.nix b/nixos/modules/services/mail/mailhog.nix
index 0f998c6d0ea63..b113f4ff3decd 100644
--- a/nixos/modules/services/mail/mailhog.nix
+++ b/nixos/modules/services/mail/mailhog.nix
@@ -4,17 +4,59 @@ with lib;
 
 let
   cfg = config.services.mailhog;
-in {
+
+  args = lib.concatStringsSep " " (
+    [
+      "-api-bind-addr :${toString cfg.apiPort}"
+      "-smtp-bind-addr :${toString cfg.smtpPort}"
+      "-ui-bind-addr :${toString cfg.uiPort}"
+      "-storage ${cfg.storage}"
+    ] ++ lib.optional (cfg.storage == "maildir")
+      "-maildir-path $STATE_DIRECTORY"
+    ++ cfg.extraArgs
+  );
+
+in
+{
   ###### interface
 
+  imports = [
+    (mkRemovedOptionModule [ "services" "mailhog" "user" ] "")
+  ];
+
   options = {
 
     services.mailhog = {
       enable = mkEnableOption "MailHog";
-      user = mkOption {
-        type = types.str;
-        default = "mailhog";
-        description = "User account under which mailhog runs.";
+
+      storage = mkOption {
+        type = types.enum [ "maildir" "memory" ];
+        default = "memory";
+        description = "Store mails on disk or in memory.";
+      };
+
+      apiPort = mkOption {
+        type = types.port;
+        default = 8025;
+        description = "Port on which the API endpoint will listen.";
+      };
+
+      smtpPort = mkOption {
+        type = types.port;
+        default = 1025;
+        description = "Port on which the SMTP endpoint will listen.";
+      };
+
+      uiPort = mkOption {
+        type = types.port;
+        default = 8025;
+        description = "Port on which the HTTP UI will listen.";
+      };
+
+      extraArgs = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        description = "List of additional arguments to pass to the MailHog process.";
       };
     };
   };
@@ -24,20 +66,16 @@ in {
 
   config = mkIf cfg.enable {
 
-    users.users.mailhog = {
-      name = cfg.user;
-      description = "MailHog service user";
-      isSystemUser = true;
-    };
-
     systemd.services.mailhog = {
-      description = "MailHog service";
+      description = "MailHog - Web and API based SMTP testing";
       after = [ "network.target" ];
       wantedBy = [ "multi-user.target" ];
       serviceConfig = {
-        Type = "simple";
-        ExecStart = "${pkgs.mailhog}/bin/MailHog";
-        User = cfg.user;
+        Type = "exec";
+        ExecStart = "${pkgs.mailhog}/bin/MailHog ${args}";
+        DynamicUser = true;
+        Restart = "on-failure";
+        StateDirectory = "mailhog";
       };
     };
   };
diff --git a/nixos/modules/services/mail/opendkim.nix b/nixos/modules/services/mail/opendkim.nix
index eb6a426684d42..9bf6f338d93ed 100644
--- a/nixos/modules/services/mail/opendkim.nix
+++ b/nixos/modules/services/mail/opendkim.nix
@@ -129,6 +129,36 @@ in {
         User = cfg.user;
         Group = cfg.group;
         RuntimeDirectory = optional (cfg.socket == defaultSock) "opendkim";
+        StateDirectory = "opendkim";
+        StateDirectoryMode = "0700";
+        ReadWritePaths = [ cfg.keyPath ];
+
+        AmbientCapabilities = [];
+        CapabilityBoundingSet = [];
+        DevicePolicy = "closed";
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        NoNewPrivileges = true;
+        PrivateDevices = true;
+        PrivateMounts = true;
+        PrivateTmp = true;
+        PrivateUsers = true;
+        ProtectClock = true;
+        ProtectControlGroups = true;
+        ProtectHome = true;
+        ProtectHostname = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectSystem = "strict";
+        RemoveIPC = true;
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6 AF_UNIX" ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+        SystemCallArchitectures = "native";
+        SystemCallFilter = [ "@system-service" "~@privileged @resources" ];
+        UMask = "0077";
       };
     };
 
diff --git a/nixos/modules/services/mail/pfix-srsd.nix b/nixos/modules/services/mail/pfix-srsd.nix
index 38984f896d6af..e3dbf2a014f06 100644
--- a/nixos/modules/services/mail/pfix-srsd.nix
+++ b/nixos/modules/services/mail/pfix-srsd.nix
@@ -53,4 +53,4 @@ with lib;
       };
     };
   };
-}
\ No newline at end of file
+}
diff --git a/nixos/modules/services/mail/postfix.nix b/nixos/modules/services/mail/postfix.nix
index 608f64a68fb09..fd4d16cdc37b0 100644
--- a/nixos/modules/services/mail/postfix.nix
+++ b/nixos/modules/services/mail/postfix.nix
@@ -25,6 +25,8 @@ let
 
   clientRestrictions = concatStringsSep ", " (clientAccess ++ dnsBl);
 
+  smtpTlsSecurityLevel = if cfg.useDane then "dane" else "may";
+
   mainCf = let
     escape = replaceStrings ["$"] ["$$"];
     mkList = items: "\n  " + concatStringsSep ",\n  " items;
@@ -280,6 +282,17 @@ in
         description = "Whether to enable smtp submission.";
       };
 
+      enableSubmissions = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to enable smtp submission via smtps.
+
+          According to RFC 8314 this should be preferred
+          over STARTTLS for submission of messages by end user clients.
+        '';
+      };
+
       submissionOptions = mkOption {
         type = types.attrs;
         default = {
@@ -298,6 +311,29 @@ in
         description = "Options for the submission config in master.cf";
       };
 
+      submissionsOptions = mkOption {
+        type = types.attrs;
+        default = {
+          smtpd_sasl_auth_enable = "yes";
+          smtpd_client_restrictions = "permit_sasl_authenticated,reject";
+          milter_macro_daemon_name = "ORIGINATING";
+        };
+        example = {
+          smtpd_sasl_auth_enable = "yes";
+          smtpd_sasl_type = "dovecot";
+          smtpd_client_restrictions = "permit_sasl_authenticated,reject";
+          milter_macro_daemon_name = "ORIGINATING";
+        };
+        description = ''
+          Options for the submission config via smtps in master.cf.
+
+          smtpd_tls_security_level will be set to encrypt, if it is missing
+          or has one of the values "may" or "none".
+
+          smtpd_tls_wrappermode with value "yes" will be added automatically.
+        '';
+      };
+
       setSendmail = mkOption {
         type = types.bool;
         default = true;
@@ -454,7 +490,7 @@ in
         '';
         example = {
           mail_owner = "postfix";
-          smtp_use_tls = true;
+          smtp_tls_security_level = "may";
         };
       };
 
@@ -466,16 +502,26 @@ in
         ";
       };
 
-      sslCert = mkOption {
+      tlsTrustedAuthorities = mkOption {
         type = types.str;
-        default = "";
-        description = "SSL certificate to use.";
+        default = "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt";
+        description = ''
+          File containing trusted certification authorities (CA) to verify certificates of mailservers contacted for mail delivery. This basically sets smtp_tls_CAfile and enables opportunistic tls. Defaults to NixOS trusted certification authorities.
+        '';
+      };
+
+      useDane = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Sets smtp_tls_security_level to "dane" rather than "may". See postconf(5) for details.
+        '';
       };
 
-      sslCACert = mkOption {
+      sslCert = mkOption {
         type = types.str;
         default = "";
-        description = "SSL certificate of CA.";
+        description = "SSL certificate to use.";
       };
 
       sslKey = mkOption {
@@ -771,18 +817,20 @@ in
         recipient_canonical_classes = [ "envelope_recipient" ];
       }
       // optionalAttrs cfg.enableHeaderChecks { header_checks = [ "regexp:/etc/postfix/header_checks" ]; }
+      // optionalAttrs (cfg.tlsTrustedAuthorities != "") {
+        smtp_tls_CAfile = cfg.tlsTrustedAuthorities;
+        smtp_tls_security_level = smtpTlsSecurityLevel;
+      }
       // optionalAttrs (cfg.sslCert != "") {
-        smtp_tls_CAfile = cfg.sslCACert;
         smtp_tls_cert_file = cfg.sslCert;
         smtp_tls_key_file = cfg.sslKey;
 
-        smtp_use_tls = true;
+        smtp_tls_security_level = smtpTlsSecurityLevel;
 
-        smtpd_tls_CAfile = cfg.sslCACert;
         smtpd_tls_cert_file = cfg.sslCert;
         smtpd_tls_key_file = cfg.sslKey;
 
-        smtpd_use_tls = true;
+        smtpd_tls_security_level = "may";
       };
 
       services.postfix.masterConfig = {
@@ -878,6 +926,23 @@ in
           command = "smtp";
           args = [ "-o" "smtp_fallback_relay=" ];
         };
+      } // optionalAttrs cfg.enableSubmissions {
+        submissions = {
+          type = "inet";
+          private = false;
+          command = "smtpd";
+          args = let
+            mkKeyVal = opt: val: [ "-o" (opt + "=" + val) ];
+            adjustSmtpTlsSecurityLevel = !(cfg.submissionsOptions ? smtpd_tls_security_level) ||
+                                      cfg.submissionsOptions.smtpd_tls_security_level == "none" ||
+                                      cfg.submissionsOptions.smtpd_tls_security_level == "may";
+            submissionsOptions = cfg.submissionsOptions // {
+              smtpd_tls_wrappermode = "yes";
+            } // optionalAttrs adjustSmtpTlsSecurityLevel {
+              smtpd_tls_security_level = "encrypt";
+            };
+          in concatLists (mapAttrsToList mkKeyVal submissionsOptions);
+        };
       };
     }
 
@@ -900,4 +965,9 @@ in
       services.postfix.mapFiles.client_access = checkClientAccessFile;
     })
   ]);
+
+  imports = [
+   (mkRemovedOptionModule [ "services" "postfix" "sslCACert" ]
+     "services.postfix.sslCACert was replaced by services.postfix.tlsTrustedAuthorities. In case you intend that your server should validate requested client certificates use services.postfix.extraConfig.")
+  ];
 }
diff --git a/nixos/modules/services/mail/roundcube.nix b/nixos/modules/services/mail/roundcube.nix
index ed1439745ac99..a0bbab64985b2 100644
--- a/nixos/modules/services/mail/roundcube.nix
+++ b/nixos/modules/services/mail/roundcube.nix
@@ -95,6 +95,18 @@ in
       '';
     };
 
+    maxAttachmentSize = mkOption {
+      type = types.int;
+      default = 18;
+      description = ''
+        The maximum attachment size in MB.
+
+        Note: Since roundcube only uses 70% of max upload values configured in php
+        30% is added automatically to <xref linkend="opt-services.roundcube.maxAttachmentSize"/>.
+      '';
+      apply = configuredMaxAttachmentSize: "${toString (configuredMaxAttachmentSize * 1.3)}M";
+    };
+
     extraConfig = mkOption {
       type = types.lines;
       default = "";
@@ -115,7 +127,7 @@ in
       $config = array();
       $config['db_dsnw'] = 'pgsql://${cfg.database.username}${lib.optionalString (!localDB) ":' . $password . '"}@${if localDB then "unix(/run/postgresql)" else cfg.database.host}/${cfg.database.dbname}';
       $config['log_driver'] = 'syslog';
-      $config['max_message_size'] = '25M';
+      $config['max_message_size'] =  '${cfg.maxAttachmentSize}';
       $config['plugins'] = [${concatMapStringsSep "," (p: "'${p}'") cfg.plugins}];
       $config['des_key'] = file_get_contents('/var/lib/roundcube/des_key');
       $config['mime_types'] = '${pkgs.nginx}/conf/mime.types';
@@ -172,8 +184,8 @@ in
       phpOptions = ''
         error_log = 'stderr'
         log_errors = on
-        post_max_size = 25M
-        upload_max_filesize = 25M
+        post_max_size = ${cfg.maxAttachmentSize}
+        upload_max_filesize = ${cfg.maxAttachmentSize}
       '';
       settings = mapAttrs (name: mkDefault) {
         "listen.owner" = "nginx";
diff --git a/nixos/modules/services/misc/beanstalkd.nix b/nixos/modules/services/misc/beanstalkd.nix
index bcd133c97411e..1c674a5b23bf0 100644
--- a/nixos/modules/services/misc/beanstalkd.nix
+++ b/nixos/modules/services/misc/beanstalkd.nix
@@ -28,6 +28,12 @@ in
           example = "0.0.0.0";
         };
       };
+
+      openFirewall = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Whether to open ports in the firewall for the server.";
+      };
     };
   };
 
@@ -35,6 +41,10 @@ in
 
   config = mkIf cfg.enable {
 
+    networking.firewall = mkIf cfg.openFirewall {
+      allowedTCPPorts = [ cfg.listen.port ];
+    };
+
     environment.systemPackages = [ pkg ];
 
     systemd.services.beanstalkd = {
diff --git a/nixos/modules/services/misc/calibre-server.nix b/nixos/modules/services/misc/calibre-server.nix
index 84c04f403d3a3..2467d34b524a5 100644
--- a/nixos/modules/services/misc/calibre-server.nix
+++ b/nixos/modules/services/misc/calibre-server.nix
@@ -9,24 +9,42 @@ let
 in
 
 {
+  imports = [
+    (mkChangedOptionModule [ "services" "calibre-server" "libraryDir" ] [ "services" "calibre-server" "libraries" ]
+      (config:
+        let libraryDir = getAttrFromPath [ "services" "calibre-server" "libraryDir" ] config;
+        in [ libraryDir ]
+      )
+    )
+  ];
 
   ###### interface
 
   options = {
-
     services.calibre-server = {
 
       enable = mkEnableOption "calibre-server";
 
-      libraryDir = mkOption {
+      libraries = mkOption {
         description = ''
-          The directory where the Calibre library to serve is.
-          '';
-          type = types.path;
+          The directories of the libraries to serve. They must be readable for the user under which the server runs.
+        '';
+        type = types.listOf types.path;
       };
 
-    };
+      user = mkOption {
+        description = "The user under which calibre-server runs.";
+        type = types.str;
+        default = "calibre-server";
+      };
+
+      group = mkOption {
+        description = "The group under which calibre-server runs.";
+        type = types.str;
+        default = "calibre-server";
+      };
 
+    };
   };
 
 
@@ -34,29 +52,34 @@ in
 
   config = mkIf cfg.enable {
 
-    systemd.services.calibre-server =
-      {
+    systemd.services.calibre-server = {
         description = "Calibre Server";
         after = [ "network.target" ];
         wantedBy = [ "multi-user.target" ];
         serviceConfig = {
-          User = "calibre-server";
+          User = cfg.user;
           Restart = "always";
-          ExecStart = "${pkgs.calibre}/bin/calibre-server ${cfg.libraryDir}";
+          ExecStart = "${pkgs.calibre}/bin/calibre-server ${lib.concatStringsSep " " cfg.libraries}";
         };
 
       };
 
     environment.systemPackages = [ pkgs.calibre ];
 
-    users.users.calibre-server = {
+    users.users = optionalAttrs (cfg.user == "calibre-server") {
+      calibre-server = {
+        home = "/var/lib/calibre-server";
+        createHome = true;
         uid = config.ids.uids.calibre-server;
-        group = "calibre-server";
+        group = cfg.group;
       };
+    };
 
-    users.groups.calibre-server = {
+    users.groups = optionalAttrs (cfg.group == "calibre-server") {
+      calibre-server = {
         gid = config.ids.gids.calibre-server;
       };
+    };
 
   };
 
diff --git a/nixos/modules/services/misc/gammu-smsd.nix b/nixos/modules/services/misc/gammu-smsd.nix
index 3057d7fd1a095..552725f1384d0 100644
--- a/nixos/modules/services/misc/gammu-smsd.nix
+++ b/nixos/modules/services/misc/gammu-smsd.nix
@@ -172,7 +172,7 @@ in {
           };
 
           database = mkOption {
-            type = types.str;
+            type = types.nullOr types.str;
             default = null;
             description = "Database name to store sms data";
           };
diff --git a/nixos/modules/services/misc/gitea.nix b/nixos/modules/services/misc/gitea.nix
index f8bcedc94fe2c..af80e99746bef 100644
--- a/nixos/modules/services/misc/gitea.nix
+++ b/nixos/modules/services/misc/gitea.nix
@@ -162,6 +162,45 @@ in
             <manvolnum>7</manvolnum></citerefentry>.
           '';
         };
+
+        backupDir = mkOption {
+          type = types.str;
+          default = "${cfg.stateDir}/dump";
+          description = "Path to the dump files.";
+        };
+      };
+
+      ssh = {
+        enable = mkOption {
+          type = types.bool;
+          default = true;
+          description = "Enable external SSH feature.";
+        };
+
+        clonePort = mkOption {
+          type = types.int;
+          default = 22;
+          example = 2222;
+          description = ''
+            SSH port displayed in clone URL.
+            The option is required to configure a service when the external visible port
+            differs from the local listening port i.e. if port forwarding is used.
+          '';
+        };
+      };
+
+      lfs = {
+        enable = mkOption {
+          type = types.bool;
+          default = false;
+          description = "Enables git-lfs support.";
+        };
+
+        contentDir = mkOption {
+          type = types.str;
+          default = "${cfg.stateDir}/data/lfs";
+          description = "Where to store LFS files.";
+        };
       };
 
       appName = mkOption {
@@ -200,6 +239,12 @@ in
         description = "HTTP listen port.";
       };
 
+      enableUnixSocket = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Configure Gitea to listen on a unix socket instead of the default TCP port.";
+      };
+
       cookieSecure = mkOption {
         type = types.bool;
         default = false;
@@ -300,14 +345,34 @@ in
         ROOT = cfg.repositoryRoot;
       };
 
-      server = {
-        DOMAIN = cfg.domain;
-        HTTP_ADDR = cfg.httpAddress;
-        HTTP_PORT = cfg.httpPort;
-        ROOT_URL = cfg.rootUrl;
-        STATIC_ROOT_PATH = cfg.staticRootPath;
-        LFS_JWT_SECRET = "#jwtsecret#";
-      };
+      server = mkMerge [
+        {
+          DOMAIN = cfg.domain;
+          STATIC_ROOT_PATH = cfg.staticRootPath;
+          LFS_JWT_SECRET = "#jwtsecret#";
+          ROOT_URL = cfg.rootUrl;
+        }
+        (mkIf cfg.enableUnixSocket {
+          PROTOCOL = "unix";
+          HTTP_ADDR = "/run/gitea/gitea.sock";
+        })
+        (mkIf (!cfg.enableUnixSocket) {
+          HTTP_ADDR = cfg.httpAddress;
+          HTTP_PORT = cfg.httpPort;
+        })
+        (mkIf cfg.ssh.enable {
+          DISABLE_SSH = false;
+          SSH_PORT = cfg.ssh.clonePort;
+        })
+        (mkIf (!cfg.ssh.enable) {
+          DISABLE_SSH = true;
+        })
+        (mkIf cfg.lfs.enable {
+          LFS_START_SERVER = true;
+          LFS_CONTENT_PATH = cfg.lfs.contentDir;
+        })
+
+      ];
 
       session = {
         COOKIE_NAME = "session";
@@ -357,12 +422,26 @@ in
     };
 
     systemd.tmpfiles.rules = [
-      "d '${cfg.stateDir}' - ${cfg.user} gitea - -"
-      "d '${cfg.stateDir}/conf' - ${cfg.user} gitea - -"
-      "d '${cfg.stateDir}/custom' - ${cfg.user} gitea - -"
-      "d '${cfg.stateDir}/custom/conf' - ${cfg.user} gitea - -"
-      "d '${cfg.stateDir}/log' - ${cfg.user} gitea - -"
-      "d '${cfg.repositoryRoot}' - ${cfg.user} gitea - -"
+      "d '${cfg.dump.backupDir}' 0750 ${cfg.user} gitea - -"
+      "z '${cfg.dump.backupDir}' 0750 ${cfg.user} gitea - -"
+      "Z '${cfg.dump.backupDir}' - ${cfg.user} gitea - -"
+      "d '${cfg.lfs.contentDir}' 0750 ${cfg.user} gitea - -"
+      "z '${cfg.lfs.contentDir}' 0750 ${cfg.user} gitea - -"
+      "Z '${cfg.lfs.contentDir}' - ${cfg.user} gitea - -"
+      "d '${cfg.repositoryRoot}' 0750 ${cfg.user} gitea - -"
+      "z '${cfg.repositoryRoot}' 0750 ${cfg.user} gitea - -"
+      "Z '${cfg.repositoryRoot}' - ${cfg.user} gitea - -"
+      "d '${cfg.stateDir}' 0750 ${cfg.user} gitea - -"
+      "d '${cfg.stateDir}/conf' 0750 ${cfg.user} gitea - -"
+      "d '${cfg.stateDir}/custom' 0750 ${cfg.user} gitea - -"
+      "d '${cfg.stateDir}/custom/conf' 0750 ${cfg.user} gitea - -"
+      "d '${cfg.stateDir}/log' 0750 ${cfg.user} gitea - -"
+      "z '${cfg.stateDir}' 0750 ${cfg.user} gitea - -"
+      "z '${cfg.stateDir}/.ssh' 0700 ${cfg.user} gitea - -"
+      "z '${cfg.stateDir}/conf' 0750 ${cfg.user} gitea - -"
+      "z '${cfg.stateDir}/custom' 0750 ${cfg.user} gitea - -"
+      "z '${cfg.stateDir}/custom/conf' 0750 ${cfg.user} gitea - -"
+      "z '${cfg.stateDir}/log' 0750 ${cfg.user} gitea - -"
       "Z '${cfg.stateDir}' - ${cfg.user} gitea - -"
 
       # If we have a folder or symlink with gitea locales, remove it
@@ -431,28 +510,39 @@ in
         User = cfg.user;
         Group = "gitea";
         WorkingDirectory = cfg.stateDir;
-        ExecStart = "${gitea}/bin/gitea web";
+        ExecStart = "${gitea}/bin/gitea web --pid /run/gitea/gitea.pid";
         Restart = "always";
-
-        # Filesystem
+        # Runtime directory and mode
+        RuntimeDirectory = "gitea";
+        RuntimeDirectoryMode = "0755";
+        # Access write directories
+        ReadWritePaths = [ cfg.dump.backupDir cfg.repositoryRoot cfg.stateDir cfg.lfs.contentDir ];
+        UMask = "0027";
+        # Capabilities
+        CapabilityBoundingSet = "";
+        # Security
+        NoNewPrivileges = true;
+        # Sandboxing
+        ProtectSystem = "strict";
         ProtectHome = true;
+        PrivateTmp = true;
         PrivateDevices = true;
+        PrivateUsers = true;
+        ProtectHostname = true;
+        ProtectClock = true;
         ProtectKernelTunables = true;
         ProtectKernelModules = true;
+        ProtectKernelLogs = true;
         ProtectControlGroups = true;
-        ReadWritePaths = cfg.stateDir;
-        # Caps
-        CapabilityBoundingSet = "";
-        NoNewPrivileges = true;
-        # Misc.
+        RestrictAddressFamilies = [ "AF_UNIX AF_INET AF_INET6" ];
         LockPersonality = true;
+        MemoryDenyWriteExecute = true;
         RestrictRealtime = true;
+        RestrictSUIDSGID = true;
         PrivateMounts = true;
-        PrivateUsers = true;
-        MemoryDenyWriteExecute = true;
-        SystemCallFilter = "~@clock @cpu-emulation @debug @keyring @memlock @module @mount @obsolete @raw-io @reboot @resources @setuid @swap";
+        # System Call Filtering
         SystemCallArchitectures = "native";
-        RestrictAddressFamilies = "AF_UNIX AF_INET AF_INET6";
+        SystemCallFilter = "~@clock @cpu-emulation @debug @keyring @memlock @module @mount @obsolete @raw-io @reboot @resources @setuid @swap";
       };
 
       environment = {
@@ -504,7 +594,7 @@ in
          Type = "oneshot";
          User = cfg.user;
          ExecStart = "${gitea}/bin/gitea dump";
-         WorkingDirectory = cfg.stateDir;
+         WorkingDirectory = cfg.dump.backupDir;
        };
     };
 
diff --git a/nixos/modules/services/misc/gitlab.nix b/nixos/modules/services/misc/gitlab.nix
index 1ada131bd7ba9..9896b8023e441 100644
--- a/nixos/modules/services/misc/gitlab.nix
+++ b/nixos/modules/services/misc/gitlab.nix
@@ -54,7 +54,7 @@ let
     '') gitlabConfig.production.repositories.storages))}
   '';
 
-  gitlabShellConfig = {
+  gitlabShellConfig = flip recursiveUpdate cfg.extraShellConfig {
     user = cfg.user;
     gitlab_url = "http+unix://${pathUrlQuote gitlabSocket}";
     http_settings.self_signed_cert = false;
@@ -71,7 +71,7 @@ let
     };
   };
 
-  redisConfig.production.url = "redis://localhost:6379/";
+  redisConfig.production.url = cfg.redisUrl;
 
   gitlabConfig = {
     # These are the default settings from config/gitlab.example.yml
@@ -311,6 +311,12 @@ in {
         description = "Extra configuration in config/database.yml.";
       };
 
+      redisUrl = mkOption {
+        type = types.str;
+        default = "redis://localhost:6379/";
+        description = "Redis URL for all GitLab services except gitlab-shell";
+      };
+
       extraGitlabRb = mkOption {
         type = types.str;
         default = "";
@@ -511,6 +517,12 @@ in {
         '';
       };
 
+      extraShellConfig = mkOption {
+        type = types.attrs;
+        default = {};
+        description = "Extra configuration to merge into shell-config.yml";
+      };
+
       extraConfig = mkOption {
         type = types.attrs;
         default = {};
@@ -612,26 +624,38 @@ in {
       enable = true;
       ensureUsers = singleton { name = cfg.databaseUsername; };
     };
+
     # The postgresql module doesn't currently support concepts like
     # objects owners and extensions; for now we tack on what's needed
     # here.
-    systemd.services.postgresql.postStart = mkAfter (optionalString databaseActuallyCreateLocally ''
-      set -eu
-
-      $PSQL -tAc "SELECT 1 FROM pg_database WHERE datname = '${cfg.databaseName}'" | grep -q 1 || $PSQL -tAc 'CREATE DATABASE "${cfg.databaseName}" OWNER "${cfg.databaseUsername}"'
-      current_owner=$($PSQL -tAc "SELECT pg_catalog.pg_get_userbyid(datdba) FROM pg_catalog.pg_database WHERE datname = '${cfg.databaseName}'")
-      if [[ "$current_owner" != "${cfg.databaseUsername}" ]]; then
-          $PSQL -tAc 'ALTER DATABASE "${cfg.databaseName}" OWNER TO "${cfg.databaseUsername}"'
-          if [[ -e "${config.services.postgresql.dataDir}/.reassigning_${cfg.databaseName}" ]]; then
-              echo "Reassigning ownership of database ${cfg.databaseName} to user ${cfg.databaseUsername} failed on last boot. Failing..."
-              exit 1
-          fi
-          touch "${config.services.postgresql.dataDir}/.reassigning_${cfg.databaseName}"
-          $PSQL "${cfg.databaseName}" -tAc "REASSIGN OWNED BY \"$current_owner\" TO \"${cfg.databaseUsername}\""
-          rm "${config.services.postgresql.dataDir}/.reassigning_${cfg.databaseName}"
-      fi
-      $PSQL '${cfg.databaseName}' -tAc "CREATE EXTENSION IF NOT EXISTS pg_trgm"
-    '');
+    systemd.services.gitlab-postgresql = let pgsql = config.services.postgresql; in mkIf databaseActuallyCreateLocally {
+      after = [ "postgresql.service" ];
+      wantedBy = [ "multi-user.target" ];
+      path = [ pgsql.package ];
+      script = ''
+        set -eu
+
+        PSQL="${pkgs.utillinux}/bin/runuser -u ${pgsql.superUser} -- psql --port=${toString pgsql.port}"
+
+        $PSQL -tAc "SELECT 1 FROM pg_database WHERE datname = '${cfg.databaseName}'" | grep -q 1 || $PSQL -tAc 'CREATE DATABASE "${cfg.databaseName}" OWNER "${cfg.databaseUsername}"'
+        current_owner=$($PSQL -tAc "SELECT pg_catalog.pg_get_userbyid(datdba) FROM pg_catalog.pg_database WHERE datname = '${cfg.databaseName}'")
+        if [[ "$current_owner" != "${cfg.databaseUsername}" ]]; then
+            $PSQL -tAc 'ALTER DATABASE "${cfg.databaseName}" OWNER TO "${cfg.databaseUsername}"'
+            if [[ -e "${config.services.postgresql.dataDir}/.reassigning_${cfg.databaseName}" ]]; then
+                echo "Reassigning ownership of database ${cfg.databaseName} to user ${cfg.databaseUsername} failed on last boot. Failing..."
+                exit 1
+            fi
+            touch "${config.services.postgresql.dataDir}/.reassigning_${cfg.databaseName}"
+            $PSQL "${cfg.databaseName}" -tAc "REASSIGN OWNED BY \"$current_owner\" TO \"${cfg.databaseUsername}\""
+            rm "${config.services.postgresql.dataDir}/.reassigning_${cfg.databaseName}"
+        fi
+        $PSQL '${cfg.databaseName}' -tAc "CREATE EXTENSION IF NOT EXISTS pg_trgm"
+      '';
+
+      serviceConfig = {
+        Type = "oneshot";
+      };
+    };
 
     # Use postfix to send out mails.
     services.postfix.enable = mkDefault true;
@@ -678,7 +702,6 @@ in {
       "L+ /run/gitlab/shell-config.yml - - - - ${pkgs.writeText "config.yml" (builtins.toJSON gitlabShellConfig)}"
 
       "L+ ${cfg.statePath}/config/unicorn.rb - - - - ${./defaultUnicornConfig.rb}"
-      "L+ ${cfg.statePath}/config/initializers/extra-gitlab.rb - - - - ${extraGitlabRb}"
     ];
 
     systemd.services.gitlab-sidekiq = {
@@ -704,7 +727,7 @@ in {
         TimeoutSec = "infinity";
         Restart = "on-failure";
         WorkingDirectory = "${cfg.packages.gitlab}/share/gitlab";
-        ExecStart="${cfg.packages.gitlab.rubyEnv}/bin/sidekiq -C \"${cfg.packages.gitlab}/share/gitlab/config/sidekiq_queues.yml\" -e production -P ${cfg.statePath}/tmp/sidekiq.pid";
+        ExecStart="${cfg.packages.gitlab.rubyEnv}/bin/sidekiq -C \"${cfg.packages.gitlab}/share/gitlab/config/sidekiq_queues.yml\" -e production";
       };
     };
 
@@ -760,8 +783,25 @@ in {
       };
     };
 
+    systemd.services.gitlab-mailroom = mkIf (gitlabConfig.production.incoming_email.enabled or false) {
+      description = "GitLab incoming mail daemon";
+      after = [ "network.target" "redis.service" "gitlab.service" ]; # gitlab.service creates configs
+      wantedBy = [ "multi-user.target" ];
+      environment = gitlabEnv;
+      serviceConfig = {
+        Type = "simple";
+        TimeoutSec = "infinity";
+        Restart = "on-failure";
+
+        User = cfg.user;
+        Group = cfg.group;
+        ExecStart = "${cfg.packages.gitlab.rubyEnv}/bin/bundle exec mail_room -c ${cfg.packages.gitlab}/share/gitlab/config.dist/mail_room.yml";
+        WorkingDirectory = gitlabEnv.HOME;
+      };
+    };
+
     systemd.services.gitlab = {
-      after = [ "gitlab-workhorse.service" "gitaly.service" "network.target" "postgresql.service" "redis.service" ];
+      after = [ "gitlab-workhorse.service" "gitaly.service" "network.target" "gitlab-postgresql.service" "redis.service" ];
       requires = [ "gitlab-sidekiq.service" ];
       wantedBy = [ "multi-user.target" ];
       environment = gitlabEnv;
@@ -798,6 +838,7 @@ in {
             rm -f ${cfg.statePath}/lib
             cp -rf --no-preserve=mode ${cfg.packages.gitlab}/share/gitlab/config.dist/* ${cfg.statePath}/config
             cp -rf --no-preserve=mode ${cfg.packages.gitlab}/share/gitlab/db/* ${cfg.statePath}/db
+            ln -sf ${extraGitlabRb} ${cfg.statePath}/config/initializers/extra-gitlab.rb
 
             ${cfg.packages.gitlab-shell}/bin/install
 
diff --git a/nixos/modules/services/misc/gitlab.xml b/nixos/modules/services/misc/gitlab.xml
index b6171a9a194c1..19a3df0a5f663 100644
--- a/nixos/modules/services/misc/gitlab.xml
+++ b/nixos/modules/services/misc/gitlab.xml
@@ -98,6 +98,12 @@ services.gitlab = {
   </para>
 
   <para>
+    When <literal>icoming_mail.enabled</literal> is set to <literal>true</literal>
+    in <link linkend="opt-services.gitlab.extraConfig">extraConfig</link> an additional
+    service called <literal>gitlab-mailroom</literal> is enabled for fetching incoming mail.
+  </para>
+
+  <para>
    Refer to <xref linkend="ch-options" /> for all available configuration
    options for the
    <link linkend="opt-services.gitlab.enable">services.gitlab</link> module.
diff --git a/nixos/modules/services/misc/gitolite.nix b/nixos/modules/services/misc/gitolite.nix
index cc69f81bbcc4b..59cbdac319c8b 100644
--- a/nixos/modules/services/misc/gitolite.nix
+++ b/nixos/modules/services/misc/gitolite.nix
@@ -27,7 +27,10 @@ in
         type = types.str;
         default = "/var/lib/gitolite";
         description = ''
-          Gitolite home directory (used to store all the repositories).
+          The gitolite home directory used to store all repositories. If left as the default value
+          this directory will automatically be created before the gitolite server starts, otherwise
+          the sysadmin is responsible for ensuring the directory exists with appropriate ownership
+          and permissions.
         '';
       };
 
@@ -149,14 +152,6 @@ in
     };
     users.groups.${cfg.group}.gid = config.ids.gids.gitolite;
 
-    systemd.tmpfiles.rules = [
-      "d '${cfg.dataDir}' 0750 ${cfg.user} ${cfg.group} - -"
-      "d '${cfg.dataDir}'/.gitolite - ${cfg.user} ${cfg.group} - -"
-      "d '${cfg.dataDir}'/.gitolite/logs - ${cfg.user} ${cfg.group} - -"
-
-      "Z ${cfg.dataDir} 0750 ${cfg.user} ${cfg.group} - -"
-    ];
-
     systemd.services.gitolite-init = {
       description = "Gitolite initialization";
       wantedBy    = [ "multi-user.target" ];
@@ -167,13 +162,19 @@ in
         GITOLITE_RC_DEFAULT = "${rcDir}/gitolite.rc.default";
       };
 
-      serviceConfig = {
-        Type = "oneshot";
-        User = cfg.user;
-        Group = cfg.group;
-        WorkingDirectory = "~";
-        RemainAfterExit = true;
-      };
+      serviceConfig = mkMerge [
+        (mkIf (cfg.dataDir == "/var/lib/gitolite") {
+          StateDirectory = "gitolite gitolite/.gitolite gitolite/.gitolite/logs";
+          StateDirectoryMode = "0750";
+        })
+        {
+          Type = "oneshot";
+          User = cfg.user;
+          Group = cfg.group;
+          WorkingDirectory = "~";
+          RemainAfterExit = true;
+        }
+      ];
 
       path = [ pkgs.gitolite pkgs.git pkgs.perl pkgs.bash pkgs.diffutils config.programs.ssh.package ];
       script =
diff --git a/nixos/modules/services/misc/gollum.nix b/nixos/modules/services/misc/gollum.nix
index f4a9c72b1545e..0c9c7548305ba 100644
--- a/nixos/modules/services/misc/gollum.nix
+++ b/nixos/modules/services/misc/gollum.nix
@@ -50,6 +50,12 @@ in
       description = "Parse and interpret emoji tags";
     };
 
+    h1-title = mkOption {
+      type = types.bool;
+      default = false;
+      description = "Use the first h1 as page title";
+    };
+
     branch = mkOption {
       type = types.str;
       default = "master";
@@ -98,10 +104,11 @@ in
           ${pkgs.gollum}/bin/gollum \
             --port ${toString cfg.port} \
             --host ${cfg.address} \
-            --config ${builtins.toFile "gollum-config.rb" cfg.extraConfig} \
+            --config ${pkgs.writeText "gollum-config.rb" cfg.extraConfig} \
             --ref ${cfg.branch} \
             ${optionalString cfg.mathjax "--mathjax"} \
             ${optionalString cfg.emoji "--emoji"} \
+            ${optionalString cfg.h1-title "--h1-title"} \
             ${optionalString (cfg.allowUploads != null) "--allow-uploads ${cfg.allowUploads}"} \
             ${cfg.stateDir}
         '';
diff --git a/nixos/modules/services/misc/home-assistant.nix b/nixos/modules/services/misc/home-assistant.nix
index 8ce2437841b07..0477254e7c18d 100644
--- a/nixos/modules/services/misc/home-assistant.nix
+++ b/nixos/modules/services/misc/home-assistant.nix
@@ -240,6 +240,7 @@ in {
       '');
       serviceConfig = {
         ExecStart = "${package}/bin/hass --config '${cfg.configDir}'";
+        ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
         User = "hass";
         Group = "hass";
         Restart = "on-failure";
diff --git a/nixos/modules/services/misc/jellyfin.nix b/nixos/modules/services/misc/jellyfin.nix
index 6ecdfb57dc358..0493dadea94ea 100644
--- a/nixos/modules/services/misc/jellyfin.nix
+++ b/nixos/modules/services/misc/jellyfin.nix
@@ -16,6 +16,14 @@ in
         description = "User account under which Jellyfin runs.";
       };
 
+      package = mkOption {
+        type = types.package;
+        example = literalExample "pkgs.jellyfin";
+        description = ''
+          Jellyfin package to use.
+        '';
+      };
+
       group = mkOption {
         type = types.str;
         default = "jellyfin";
@@ -35,11 +43,16 @@ in
         Group = cfg.group;
         StateDirectory = "jellyfin";
         CacheDirectory = "jellyfin";
-        ExecStart = "${pkgs.jellyfin}/bin/jellyfin --datadir '/var/lib/${StateDirectory}' --cachedir '/var/cache/${CacheDirectory}'";
+        ExecStart = "${cfg.package}/bin/jellyfin --datadir '/var/lib/${StateDirectory}' --cachedir '/var/cache/${CacheDirectory}'";
         Restart = "on-failure";
       };
     };
 
+    services.jellyfin.package = mkDefault (
+      if versionAtLeast config.system.stateVersion "20.09" then pkgs.jellyfin
+        else pkgs.jellyfin_10_5
+    );
+
     users.users = mkIf (cfg.user == "jellyfin") {
       jellyfin = {
         group = cfg.group;
diff --git a/nixos/modules/services/misc/mathics.nix b/nixos/modules/services/misc/mathics.nix
deleted file mode 100644
index c588a30d76cd1..0000000000000
--- a/nixos/modules/services/misc/mathics.nix
+++ /dev/null
@@ -1,54 +0,0 @@
-{ pkgs, lib, config, ... }:
-
-with lib;
-
-let
-  cfg = config.services.mathics;
-
-in {
-  options = {
-    services.mathics = {
-      enable = mkEnableOption "Mathics notebook service";
-
-      external = mkOption {
-        type = types.bool;
-        default = false;
-        description = "Listen on all interfaces, rather than just localhost?";
-      };
-
-      port = mkOption {
-        type = types.int;
-        default = 8000;
-        description = "TCP port to listen on.";
-      };
-    };
-  };
-
-  config = mkIf cfg.enable {
-
-    users.users.mathics = {
-      group = config.users.groups.mathics.name;
-      description = "Mathics user";
-      home = "/var/lib/mathics";
-      createHome = true;
-      uid = config.ids.uids.mathics;
-    };
-
-    users.groups.mathics.gid = config.ids.gids.mathics;
-
-    systemd.services.mathics = {
-      description = "Mathics notebook server";
-      wantedBy = [ "multi-user.target" ];
-      after = [ "network.target" ];
-      serviceConfig = {
-        User = config.users.users.mathics.name;
-        Group = config.users.groups.mathics.name;
-        ExecStart = concatStringsSep " " [
-          "${pkgs.mathics}/bin/mathicsserver"
-          "--port" (toString cfg.port)
-          (if cfg.external then "--external" else "")
-        ];
-      };
-    };
-  };
-}
diff --git a/nixos/modules/services/misc/matrix-synapse.nix b/nixos/modules/services/misc/matrix-synapse.nix
index e982eb16fa70f..3eb1073387fec 100644
--- a/nixos/modules/services/misc/matrix-synapse.nix
+++ b/nixos/modules/services/misc/matrix-synapse.nix
@@ -675,7 +675,7 @@ in {
       }
     ];
 
-    users.users.matrix-synapse = { 
+    users.users.matrix-synapse = {
         group = "matrix-synapse";
         home = cfg.dataDir;
         createHome = true;
diff --git a/nixos/modules/services/misc/matrix-synapse.xml b/nixos/modules/services/misc/matrix-synapse.xml
index 2f2ac27eeb9d0..fbfa838b168bf 100644
--- a/nixos/modules/services/misc/matrix-synapse.xml
+++ b/nixos/modules/services/misc/matrix-synapse.xml
@@ -14,9 +14,9 @@
  <para>
   This chapter will show you how to set up your own, self-hosted Matrix
   homeserver using the Synapse reference homeserver, and how to serve your own
-  copy of the Riot web client. See the
+  copy of the Element web client. See the
   <link xlink:href="https://matrix.org/docs/projects/try-matrix-now.html">Try
-  Matrix Now!</link> overview page for links to Riot Apps for Android and iOS,
+  Matrix Now!</link> overview page for links to Element Apps for Android and iOS,
   desktop clients, as well as bridges to other networks and other projects
   around Matrix.
  </para>
@@ -84,7 +84,7 @@ in {
               "m.homeserver" =  { "base_url" = "https://${fqdn}"; };
               "m.identity_server" =  { "base_url" = "https://vector.im"; };
             };
-          # ACAO required to allow riot-web on any URL to request this json file
+          # ACAO required to allow element-web on any URL to request this json file
           in ''
             add_header Content-Type application/json;
             add_header Access-Control-Allow-Origin *;
@@ -98,7 +98,7 @@ in {
         <link linkend="opt-services.nginx.virtualHosts._name_.forceSSL">forceSSL</link> = true;
 
         # Or do a redirect instead of the 404, or whatever is appropriate for you.
-        # But do not put a Matrix Web client here! See the Riot Web section below.
+        # But do not put a Matrix Web client here! See the Element web section below.
         <link linkend="opt-services.nginx.virtualHosts._name_.locations._name_.extraConfig">locations."/".extraConfig</link> = ''
           return 404;
         '';
@@ -171,17 +171,19 @@ Success!
    option until a better solution for NixOS is in place.
   </para>
  </section>
- <section xml:id="module-services-matrix-riot-web">
-  <title>Riot Web Client</title>
+ <section xml:id="module-services-matrix-element-web">
+  <title>Element (formerly known as Riot) Web Client</title>
 
   <para>
-   <link xlink:href="https://github.com/vector-im/riot-web/">Riot Web</link> is
+   <link xlink:href="https://github.com/vector-im/riot-web/">Element Web</link> is
    the reference web client for Matrix and developed by the core team at
-   matrix.org. The following snippet can be optionally added to the code before
+   matrix.org. Element was formerly known as Riot.im, see the
+   <link xlink:href="https://element.io/blog/welcome-to-element/">Element introductory blog post</link>
+   for more information. The following snippet can be optionally added to the code before
    to complete the synapse installation with a web client served at
-   <code>https://riot.myhostname.example.org</code> and
-   <code>https://riot.example.org</code>. Alternatively, you can use the hosted
-   copy at <link xlink:href="https://riot.im/app">https://riot.im/app</link>,
+   <code>https://element.myhostname.example.org</code> and
+   <code>https://element.example.org</code>. Alternatively, you can use the hosted
+   copy at <link xlink:href="https://app.element.io/">https://app.element.io/</link>,
    or use other web clients or native client applications. Due to the
    <literal>/.well-known</literal> urls set up done above, many clients should
    fill in the required connection details automatically when you enter your
@@ -191,14 +193,14 @@ Success!
    featureset.
 <programlisting>
 {
-  services.nginx.virtualHosts."riot.${fqdn}" = {
+  services.nginx.virtualHosts."element.${fqdn}" = {
     <link linkend="opt-services.nginx.virtualHosts._name_.enableACME">enableACME</link> = true;
     <link linkend="opt-services.nginx.virtualHosts._name_.forceSSL">forceSSL</link> = true;
     <link linkend="opt-services.nginx.virtualHosts._name_.serverAliases">serverAliases</link> = [
-      "riot.${config.networking.domain}"
+      "element.${config.networking.domain}"
     ];
 
-    <link linkend="opt-services.nginx.virtualHosts._name_.root">root</link> = pkgs.riot-web.override {
+    <link linkend="opt-services.nginx.virtualHosts._name_.root">root</link> = pkgs.element-web.override {
       conf = {
         default_server_config."m.homeserver" = {
           "base_url" = "${config.networking.domain}";
@@ -212,13 +214,13 @@ Success!
   </para>
 
   <para>
-   Note that the Riot developers do not recommend running Riot and your Matrix
+   Note that the Element developers do not recommend running Element and your Matrix
    homeserver on the same fully-qualified domain name for security reasons. In
    the example, this means that you should not reuse the
-   <literal>myhostname.example.org</literal> virtualHost to also serve Riot,
+   <literal>myhostname.example.org</literal> virtualHost to also serve Element,
    but instead serve it on a different subdomain, like
-   <literal>riot.example.org</literal> in the example. See the
-   <link xlink:href="https://github.com/vector-im/riot-web#important-security-note">Riot
+   <literal>element.example.org</literal> in the example. See the
+   <link xlink:href="https://github.com/vector-im/riot-web#important-security-note">Element
    Important Security Notes</link> for more information on this subject.
   </para>
  </section>
diff --git a/nixos/modules/services/misc/mautrix-telegram.nix b/nixos/modules/services/misc/mautrix-telegram.nix
index 78a42fbb574b4..c5e8a5b85ec2d 100644
--- a/nixos/modules/services/misc/mautrix-telegram.nix
+++ b/nixos/modules/services/misc/mautrix-telegram.nix
@@ -125,7 +125,7 @@ in {
         if [ ! -f '${registrationFile}' ]; then
           ${pkgs.mautrix-telegram}/bin/mautrix-telegram \
             --generate-registration \
-            --base-config='${pkgs.mautrix-telegram}/example-config.yaml' \
+            --base-config='${pkgs.mautrix-telegram}/${pkgs.mautrix-telegram.pythonModule.sitePackages}/mautrix_telegram/example-config.yaml' \
             --config='${settingsFile}' \
             --registration='${registrationFile}'
         fi
diff --git a/nixos/modules/services/misc/mesos-master.nix b/nixos/modules/services/misc/mesos-master.nix
deleted file mode 100644
index 572a9847e46c6..0000000000000
--- a/nixos/modules/services/misc/mesos-master.nix
+++ /dev/null
@@ -1,125 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-with lib;
-
-let
-  cfg = config.services.mesos.master;
-
-in {
-
-  options.services.mesos = {
-
-    master = {
-      enable = mkOption {
-        description = "Whether to enable the Mesos Master.";
-        default = false;
-        type = types.bool;
-      };
-
-      ip = mkOption {
-        description = "IP address to listen on.";
-        default = "0.0.0.0";
-        type = types.str;
-      };
-
-      port = mkOption {
-        description = "Mesos Master port";
-        default = 5050;
-        type = types.int;
-      };
-
-      advertiseIp = mkOption {
-        description = "IP address advertised to reach this master.";
-        default = null;
-        type = types.nullOr types.str;
-      };
-
-      advertisePort = mkOption {
-        description = "Port advertised to reach this Mesos master.";
-        default = null;
-        type = types.nullOr types.int;
-      };
-
-      zk = mkOption {
-        description = ''
-          ZooKeeper URL (used for leader election amongst masters).
-          May be one of:
-            zk://host1:port1,host2:port2,.../mesos
-            zk://username:password@host1:port1,host2:port2,.../mesos
-        '';
-        type = types.str;
-      };
-
-      workDir = mkOption {
-        description = "The Mesos work directory.";
-        default = "/var/lib/mesos/master";
-        type = types.str;
-      };
-
-      extraCmdLineOptions = mkOption {
-        description = ''
-          Extra command line options for Mesos Master.
-
-          See https://mesos.apache.org/documentation/latest/configuration/
-        '';
-        default = [ "" ];
-        type = types.listOf types.str;
-        example = [ "--credentials=VALUE" ];
-      };
-
-      quorum = mkOption {
-        description = ''
-          The size of the quorum of replicas when using 'replicated_log' based
-          registry. It is imperative to set this value to be a majority of
-          masters i.e., quorum > (number of masters)/2.
-
-          If 0 will fall back to --registry=in_memory.
-        '';
-        default = 0;
-        type = types.int;
-      };
-
-      logLevel = mkOption {
-        description = ''
-          The logging level used. Possible values:
-            'INFO', 'WARNING', 'ERROR'
-        '';
-        default = "INFO";
-        type = types.str;
-      };
-
-    };
-
-
-  };
-
-
-  config = mkIf cfg.enable {
-    systemd.tmpfiles.rules = [
-      "d '${cfg.workDir}' 0700 - - - -"
-    ];
-    systemd.services.mesos-master = {
-      description = "Mesos Master";
-      wantedBy = [ "multi-user.target" ];
-      after = [ "network.target" ];
-      serviceConfig = {
-        ExecStart = ''
-          ${pkgs.mesos}/bin/mesos-master \
-            --ip=${cfg.ip} \
-            --port=${toString cfg.port} \
-            ${optionalString (cfg.advertiseIp != null) "--advertise_ip=${cfg.advertiseIp}"} \
-            ${optionalString (cfg.advertisePort  != null) "--advertise_port=${toString cfg.advertisePort}"} \
-            ${if cfg.quorum == 0
-              then "--registry=in_memory"
-              else "--zk=${cfg.zk} --registry=replicated_log --quorum=${toString cfg.quorum}"} \
-            --work_dir=${cfg.workDir} \
-            --logging_level=${cfg.logLevel} \
-            ${toString cfg.extraCmdLineOptions}
-        '';
-        Restart = "on-failure";
-      };
-    };
-  };
-
-}
-
diff --git a/nixos/modules/services/misc/mesos-slave.nix b/nixos/modules/services/misc/mesos-slave.nix
deleted file mode 100644
index 170065d0065e0..0000000000000
--- a/nixos/modules/services/misc/mesos-slave.nix
+++ /dev/null
@@ -1,220 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-with lib;
-
-let
-  cfg = config.services.mesos.slave;
-
-  mkAttributes =
-    attrs: concatStringsSep ";" (mapAttrsToList
-                                   (k: v: "${k}:${v}")
-                                   (filterAttrs (k: v: v != null) attrs));
-  attribsArg = optionalString (cfg.attributes != {})
-                              "--attributes=${mkAttributes cfg.attributes}";
-
-  containerizersArg = concatStringsSep "," (
-    lib.unique (
-      cfg.containerizers ++ (optional cfg.withDocker "docker")
-    )
-  );
-
-  imageProvidersArg = concatStringsSep "," (
-    lib.unique (
-      cfg.imageProviders ++ (optional cfg.withDocker "docker")
-    )
-  );
-
-  isolationArg = concatStringsSep "," (
-    lib.unique (
-      cfg.isolation ++ (optionals cfg.withDocker [ "filesystem/linux" "docker/runtime"])
-    )
-  );
-
-in {
-
-  options.services.mesos = {
-    slave = {
-      enable = mkOption {
-        description = "Whether to enable the Mesos Slave.";
-        default = false;
-        type = types.bool;
-      };
-
-      ip = mkOption {
-        description = "IP address to listen on.";
-        default = "0.0.0.0";
-        type = types.str;
-      };
-
-      port = mkOption {
-        description = "Port to listen on.";
-        default = 5051;
-        type = types.int;
-      };
-
-      advertiseIp = mkOption {
-        description = "IP address advertised to reach this agent.";
-        default = null;
-        type = types.nullOr types.str;
-      };
-
-      advertisePort = mkOption {
-        description = "Port advertised to reach this agent.";
-        default = null;
-        type = types.nullOr types.int;
-      };
-
-      containerizers = mkOption {
-        description = ''
-          List of containerizer implementations to compose in order to provide
-          containerization. Available options are mesos and docker.
-          The order the containerizers are specified is the order they are tried.
-        '';
-        default = [ "mesos" ];
-        type = types.listOf types.str;
-      };
-
-      imageProviders = mkOption {
-        description = "List of supported image providers, e.g., APPC,DOCKER.";
-        default = [ ];
-        type = types.listOf types.str;
-      };
-
-      imageProvisionerBackend = mkOption {
-        description = ''
-          Strategy for provisioning container rootfs from images,
-          e.g., aufs, bind, copy, overlay.
-        '';
-        default = "copy";
-        type = types.str;
-      };
-
-      isolation = mkOption {
-        description = ''
-          Isolation mechanisms to use, e.g., posix/cpu,posix/mem, or
-          cgroups/cpu,cgroups/mem, or network/port_mapping, or `gpu/nvidia` for nvidia
-          specific gpu isolation.
-        '';
-        default = [ "posix/cpu" "posix/mem" ];
-        type = types.listOf types.str;
-      };
-
-      master = mkOption {
-        description = ''
-          May be one of:
-            zk://host1:port1,host2:port2,.../path
-            zk://username:password@host1:port1,host2:port2,.../path
-        '';
-        type = types.str;
-      };
-
-      withHadoop = mkOption {
-        description = "Add the HADOOP_HOME to the slave.";
-        default = false;
-        type = types.bool;
-      };
-
-      withDocker = mkOption {
-        description = "Enable the docker containerizer.";
-        default = config.virtualisation.docker.enable;
-        type = types.bool;
-      };
-
-      dockerRegistry = mkOption {
-        description = ''
-          The default url for pulling Docker images.
-          It could either be a Docker registry server url,
-          or a local path in which Docker image archives are stored.
-        '';
-        default = null;
-        type = types.nullOr (types.either types.str types.path);
-      };
-
-      workDir = mkOption {
-        description = "The Mesos work directory.";
-        default = "/var/lib/mesos/slave";
-        type = types.str;
-      };
-
-      extraCmdLineOptions = mkOption {
-        description = ''
-          Extra command line options for Mesos Slave.
-
-          See https://mesos.apache.org/documentation/latest/configuration/
-        '';
-        default = [ "" ];
-        type = types.listOf types.str;
-        example = [ "--gc_delay=3days" ];
-      };
-
-      logLevel = mkOption {
-        description = ''
-          The logging level used. Possible values:
-            'INFO', 'WARNING', 'ERROR'
-        '';
-        default = "INFO";
-        type = types.str;
-      };
-
-      attributes = mkOption {
-        description = ''
-          Machine attributes for the slave instance.
-
-          Use caution when changing this; you may need to manually reset slave
-          metadata before the slave can re-register.
-        '';
-        default = {};
-        type = types.attrsOf types.str;
-        example = { rack = "aa";
-                    host = "aabc123";
-                    os = "nixos"; };
-      };
-
-      executorEnvironmentVariables = mkOption {
-        description = ''
-          The environment variables that should be passed to the executor, and thus subsequently task(s).
-        '';
-        default = {
-          PATH = "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin";
-        };
-        type = types.attrsOf types.str;
-      };
-    };
-
-  };
-
-  config = mkIf cfg.enable {
-    systemd.tmpfiles.rules = [
-      "d '${cfg.workDir}' 0701 - - - -"
-    ];
-    systemd.services.mesos-slave = {
-      description = "Mesos Slave";
-      wantedBy = [ "multi-user.target" ];
-      after = [ "network.target" ] ++ optionals cfg.withDocker [ "docker.service" ] ;
-      path = [ pkgs.runtimeShellPackage ];
-      serviceConfig = {
-        ExecStart = ''
-          ${pkgs.mesos}/bin/mesos-slave \
-            --containerizers=${containerizersArg} \
-            --image_providers=${imageProvidersArg} \
-            --image_provisioner_backend=${cfg.imageProvisionerBackend} \
-            --isolation=${isolationArg} \
-            --ip=${cfg.ip} \
-            --port=${toString cfg.port} \
-            ${optionalString (cfg.advertiseIp != null) "--advertise_ip=${cfg.advertiseIp}"} \
-            ${optionalString (cfg.advertisePort  != null) "--advertise_port=${toString cfg.advertisePort}"} \
-            --master=${cfg.master} \
-            --work_dir=${cfg.workDir} \
-            --logging_level=${cfg.logLevel} \
-            ${attribsArg} \
-            ${optionalString cfg.withHadoop "--hadoop-home=${pkgs.hadoop}"} \
-            ${optionalString cfg.withDocker "--docker=${pkgs.docker}/libexec/docker/docker"} \
-            ${optionalString (cfg.dockerRegistry != null) "--docker_registry=${cfg.dockerRegistry}"} \
-            --executor_environment_variables=${lib.escapeShellArg (builtins.toJSON cfg.executorEnvironmentVariables)} \
-            ${toString cfg.extraCmdLineOptions}
-        '';
-      };
-    };
-  };
-
-}
diff --git a/nixos/modules/services/misc/nix-daemon.nix b/nixos/modules/services/misc/nix-daemon.nix
index 0b3d7f3f03c3d..2680b1cc0d3b8 100644
--- a/nixos/modules/services/misc/nix-daemon.nix
+++ b/nixos/modules/services/misc/nix-daemon.nix
@@ -193,50 +193,111 @@ in
       };
 
       buildMachines = mkOption {
-        type = types.listOf types.attrs;
+        type = types.listOf (types.submodule ({
+          options = {
+            hostName = mkOption {
+              type = types.str;
+              example = "nixbuilder.example.org";
+              description = ''
+                The hostname of the build machine.
+              '';
+            };
+            system = mkOption {
+              type = types.nullOr types.str;
+              default = null;
+              example = "x86_64-linux";
+              description = ''
+                The system type the build machine can execute derivations on.
+                Either this attribute or <varname>systems</varname> must be
+                present, where <varname>system</varname> takes precedence if
+                both are set.
+              '';
+            };
+            systems = mkOption {
+              type = types.listOf types.str;
+              default = [];
+              example = [ "x86_64-linux" "aarch64-linux" ];
+              description = ''
+                The system types the build machine can execute derivations on.
+                Either this attribute or <varname>system</varname> must be
+                present, where <varname>system</varname> takes precedence if
+                both are set.
+              '';
+            };
+            sshUser = mkOption {
+              type = types.nullOr types.str;
+              default = null;
+              example = "builder";
+              description = ''
+                The username to log in as on the remote host. This user must be
+                able to log in and run nix commands non-interactively. It must
+                also be privileged to build derivations, so must be included in
+                <option>nix.trustedUsers</option>.
+              '';
+            };
+            sshKey = mkOption {
+              type = types.nullOr types.str;
+              default = null;
+              example = "/root/.ssh/id_buildhost_builduser";
+              description = ''
+                The path to the SSH private key with which to authenticate on
+                the build machine. The private key must not have a passphrase.
+                If null, the building user (root on NixOS machines) must have an
+                appropriate ssh configuration to log in non-interactively.
+
+                Note that for security reasons, this path must point to a file
+                in the local filesystem, *not* to the nix store.
+              '';
+            };
+            maxJobs = mkOption {
+              type = types.int;
+              default = 1;
+              description = ''
+                The number of concurrent jobs the build machine supports. The
+                build machine will enforce its own limits, but this allows hydra
+                to schedule better since there is no work-stealing between build
+                machines.
+              '';
+            };
+            speedFactor = mkOption {
+              type = types.int;
+              default = 1;
+              description = ''
+                The relative speed of this builder. This is an arbitrary integer
+                that indicates the speed of this builder, relative to other
+                builders. Higher is faster.
+              '';
+            };
+            mandatoryFeatures = mkOption {
+              type = types.listOf types.str;
+              default = [];
+              example = [ "big-parallel" ];
+              description = ''
+                A list of features mandatory for this builder. The builder will
+                be ignored for derivations that don't require all features in
+                this list. All mandatory features are automatically included in
+                <varname>supportedFeatures</varname>.
+              '';
+            };
+            supportedFeatures = mkOption {
+              type = types.listOf types.str;
+              default = [];
+              example = [ "kvm" "big-parallel" ];
+              description = ''
+                A list of features supported by this builder. The builder will
+                be ignored for derivations that require features not in this
+                list.
+              '';
+            };
+          };
+        }));
         default = [];
-        example = literalExample ''
-          [ { hostName = "voila.labs.cs.uu.nl";
-              sshUser = "nix";
-              sshKey = "/root/.ssh/id_buildfarm";
-              system = "powerpc-darwin";
-              maxJobs = 1;
-            }
-            { hostName = "linux64.example.org";
-              sshUser = "buildfarm";
-              sshKey = "/root/.ssh/id_buildfarm";
-              system = "x86_64-linux";
-              maxJobs = 2;
-              speedFactor = 2;
-              supportedFeatures = [ "kvm" ];
-              mandatoryFeatures = [ "perf" ];
-            }
-          ]
-        '';
         description = ''
-          This option lists the machines to be used if distributed
-          builds are enabled (see
-          <option>nix.distributedBuilds</option>).  Nix will perform
-          derivations on those machines via SSH by copying the inputs
-          to the Nix store on the remote machine, starting the build,
-          then copying the output back to the local Nix store.  Each
-          element of the list should be an attribute set containing
-          the machine's host name (<varname>hostname</varname>), the
-          user name to be used for the SSH connection
-          (<varname>sshUser</varname>), the Nix system type
-          (<varname>system</varname>, e.g.,
-          <literal>"i686-linux"</literal>), the maximum number of
-          jobs to be run in parallel on that machine
-          (<varname>maxJobs</varname>), the path to the SSH private
-          key to be used to connect (<varname>sshKey</varname>), a
-          list of supported features of the machine
-          (<varname>supportedFeatures</varname>) and a list of
-          mandatory features of the machine
-          (<varname>mandatoryFeatures</varname>). The SSH private key
-          should not have a passphrase, and the corresponding public
-          key should be added to
-          <filename>~<replaceable>sshUser</replaceable>/authorized_keys</filename>
-          on the remote machine.
+          This option lists the machines to be used if distributed builds are
+          enabled (see <option>nix.distributedBuilds</option>).
+          Nix will perform derivations on those machines via SSH by copying the
+          inputs to the Nix store on the remote machine, starting the build,
+          then copying the output back to the local Nix store.
         '';
       };
 
@@ -461,14 +522,14 @@ in
       { enable = cfg.buildMachines != [];
         text =
           concatMapStrings (machine:
-            "${if machine ? sshUser then "${machine.sshUser}@" else ""}${machine.hostName} "
-            + machine.system or (concatStringsSep "," machine.systems)
-            + " ${machine.sshKey or "-"} ${toString machine.maxJobs or 1} "
-            + toString (machine.speedFactor or 1)
+            "${if machine.sshUser != null then "${machine.sshUser}@" else ""}${machine.hostName} "
+            + (if machine.system != null then machine.system else concatStringsSep "," machine.systems)
+            + " ${if machine.sshKey != null then machine.sshKey else "-"} ${toString machine.maxJobs} "
+            + toString (machine.speedFactor)
             + " "
-            + concatStringsSep "," (machine.mandatoryFeatures or [] ++ machine.supportedFeatures or [])
+            + concatStringsSep "," (machine.mandatoryFeatures ++ machine.supportedFeatures)
             + " "
-            + concatStringsSep "," machine.mandatoryFeatures or []
+            + concatStringsSep "," machine.mandatoryFeatures
             + "\n"
           ) cfg.buildMachines;
       };
@@ -526,16 +587,10 @@ in
 
     nix.systemFeatures = mkDefault (
       [ "nixos-test" "benchmark" "big-parallel" "kvm" ] ++
-      optionals (pkgs.stdenv.isx86_64 && pkgs.hostPlatform.platform ? gcc.arch) (
-        # a x86_64 builder can run code for `platform.gcc.arch` and minor architectures:
-        [ "gccarch-${pkgs.hostPlatform.platform.gcc.arch}" ] ++ {
-          sandybridge    = [ "gccarch-westmere" ];
-          ivybridge      = [ "gccarch-westmere" "gccarch-sandybridge" ];
-          haswell        = [ "gccarch-westmere" "gccarch-sandybridge" "gccarch-ivybridge" ];
-          broadwell      = [ "gccarch-westmere" "gccarch-sandybridge" "gccarch-ivybridge" "gccarch-haswell" ];
-          skylake        = [ "gccarch-westmere" "gccarch-sandybridge" "gccarch-ivybridge" "gccarch-haswell" "gccarch-broadwell" ];
-          skylake-avx512 = [ "gccarch-westmere" "gccarch-sandybridge" "gccarch-ivybridge" "gccarch-haswell" "gccarch-broadwell" "gccarch-skylake" ];
-        }.${pkgs.hostPlatform.platform.gcc.arch} or []
+      optionals (pkgs.hostPlatform.platform ? gcc.arch) (
+        # a builder can run code for `platform.gcc.arch` and inferior architectures
+        [ "gccarch-${pkgs.hostPlatform.platform.gcc.arch}" ] ++
+        map (x: "gccarch-${x}") lib.systems.architectures.inferiors.${pkgs.hostPlatform.platform.gcc.arch}
       )
     );
 
diff --git a/nixos/modules/services/misc/octoprint.nix b/nixos/modules/services/misc/octoprint.nix
index 7a71d2c8c6aa6..e2fbd3b401cc5 100644
--- a/nixos/modules/services/misc/octoprint.nix
+++ b/nixos/modules/services/misc/octoprint.nix
@@ -68,8 +68,8 @@ in
       plugins = mkOption {
         default = plugins: [];
         defaultText = "plugins: []";
-        example = literalExample "plugins: [ m3d-fio ]";
-        description = "Additional plugins.";
+        example = literalExample "plugins: with plugins; [ m33-fio stlviewer ]";
+        description = "Additional plugins to be used. Available plugins are passed through the plugins input.";
       };
 
       extraConfig = mkOption {
diff --git a/nixos/modules/services/misc/pinnwand.nix b/nixos/modules/services/misc/pinnwand.nix
new file mode 100644
index 0000000000000..aa1ee5cfaa77d
--- /dev/null
+++ b/nixos/modules/services/misc/pinnwand.nix
@@ -0,0 +1,78 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.pinnwand;
+
+  format = pkgs.formats.toml {};
+  configFile = format.generate "pinnwand.toml" cfg.settings;
+in
+{
+  options.services.pinnwand = {
+    enable = mkEnableOption "Pinnwand";
+
+    port = mkOption {
+      type = types.port;
+      description = "The port to listen on.";
+      default = 8000;
+    };
+
+    settings = mkOption {
+      type = format.type;
+      description = ''
+        Your <filename>pinnwand.toml</filename> as a Nix attribute set. Look up
+        possible options in the <link xlink:href="https://github.com/supakeen/pinnwand/blob/master/pinnwand.toml-example">pinnwand.toml-example</link>.
+      '';
+      default = {
+        # https://github.com/supakeen/pinnwand/blob/master/pinnwand.toml-example
+        database_uri = "sqlite:///var/lib/pinnwand/pinnwand.db";
+        preferred_lexeres = [];
+        paste_size = 262144;
+        paste_help = ''
+          <p>Welcome to pinnwand, this site is a pastebin. It allows you to share code with others. If you write code in the text area below and press the paste button you will be given a link you can share with others so they can view your code as well.</p><p>People with the link can view your pasted code, only you can remove your paste and it expires automatically. Note that anyone could guess the URI to your paste so don't rely on it being private.</p>
+        '';
+        footer = ''
+          View <a href="//github.com/supakeen/pinnwand" target="_BLANK">source code</a>, the <a href="/removal">removal</a> or <a href="/expiry">expiry</a> stories, or read the <a href="/about">about</a> page.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.pinnwand = {
+      description = "Pinnwannd HTTP Server";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+
+      unitConfig.Documentation = "https://pinnwand.readthedocs.io/en/latest/";
+      serviceConfig = {
+        ExecStart = "${pkgs.pinnwand}/bin/pinnwand --configuration-path ${configFile} http --port ${toString(cfg.port)}";
+        StateDirectory = "pinnwand";
+        StateDirectoryMode = "0700";
+
+        AmbientCapabilities = [];
+        CapabilityBoundingSet = "";
+        DevicePolicy = "closed";
+        DynamicUser = true;
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        PrivateDevices = true;
+        PrivateUsers = true;
+        ProtectClock = true;
+        ProtectControlGroups = true;
+        ProtectKernelLogs = true;
+        ProtectHome = true;
+        ProtectHostname = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        RestrictAddressFamilies = [ "AF_UNIX" "AF_INET" "AF_INET6" ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        SystemCallArchitectures = "native";
+        SystemCallFilter = "@system-service";
+        UMask = "0077";
+      };
+    };
+  };
+}
diff --git a/nixos/modules/services/misc/redmine.nix b/nixos/modules/services/misc/redmine.nix
index 0e71cf925692c..1313bdaccc49a 100644
--- a/nixos/modules/services/misc/redmine.nix
+++ b/nixos/modules/services/misc/redmine.nix
@@ -1,12 +1,12 @@
 { config, lib, pkgs, ... }:
 
 let
-  inherit (lib) mkDefault mkEnableOption mkIf mkOption types;
+  inherit (lib) mkBefore mkDefault mkEnableOption mkIf mkOption mkRemovedOptionModule types;
   inherit (lib) concatStringsSep literalExample mapAttrsToList;
-  inherit (lib) optional optionalAttrs optionalString singleton versionAtLeast;
+  inherit (lib) optional optionalAttrs optionalString;
 
   cfg = config.services.redmine;
-
+  format = pkgs.formats.yaml {};
   bundle = "${cfg.package}/share/redmine/bin/bundle";
 
   databaseYml = pkgs.writeText "database.yml" ''
@@ -20,24 +20,8 @@ let
       ${optionalString (cfg.database.type == "mysql2" && cfg.database.socket != null) "socket: ${cfg.database.socket}"}
   '';
 
-  configurationYml = pkgs.writeText "configuration.yml" ''
-    default:
-      scm_subversion_command: ${pkgs.subversion}/bin/svn
-      scm_mercurial_command: ${pkgs.mercurial}/bin/hg
-      scm_git_command: ${pkgs.gitAndTools.git}/bin/git
-      scm_cvs_command: ${pkgs.cvs}/bin/cvs
-      scm_bazaar_command: ${pkgs.breezy}/bin/bzr
-      scm_darcs_command: ${pkgs.darcs}/bin/darcs
-
-    ${cfg.extraConfig}
-  '';
-
-  additionalEnvironment = pkgs.writeText "additional_environment.rb" ''
-    config.logger = Logger.new("${cfg.stateDir}/log/production.log", 14, 1048576)
-    config.logger.level = Logger::INFO
-
-    ${cfg.extraEnv}
-  '';
+  configurationYml = format.generate "configuration.yml" cfg.settings;
+  additionalEnvironment = pkgs.writeText "additional_environment.rb" cfg.extraEnv;
 
   unpackTheme = unpack "theme";
   unpackPlugin = unpack "plugin";
@@ -56,8 +40,13 @@ let
   pgsqlLocal = cfg.database.createLocally && cfg.database.type == "postgresql";
 
 in
-
 {
+  imports = [
+    (mkRemovedOptionModule [ "services" "redmine" "extraConfig" ] "Use services.redmine.settings instead.")
+    (mkRemovedOptionModule [ "services" "redmine" "database" "password" ] "Use services.redmine.database.passwordFile instead.")
+  ];
+
+  # interface
   options = {
     services.redmine = {
       enable = mkEnableOption "Redmine";
@@ -93,21 +82,24 @@ in
         description = "The state directory, logs and plugins are stored here.";
       };
 
-      extraConfig = mkOption {
-        type = types.lines;
-        default = "";
+      settings = mkOption {
+        type = format.type;
+        default = {};
         description = ''
-          Extra configuration in configuration.yml.
-
-          See <link xlink:href="https://guides.rubyonrails.org/action_mailer_basics.html#action-mailer-configuration"/>
+          Redmine configuration (<filename>configuration.yml</filename>). Refer to
+          <link xlink:href="https://guides.rubyonrails.org/action_mailer_basics.html#action-mailer-configuration"/>
           for details.
         '';
         example = literalExample ''
-          email_delivery:
-            delivery_method: smtp
-            smtp_settings:
-              address: mail.example.com
-              port: 25
+          {
+            email_delivery = {
+              delivery_method = "smtp";
+              smtp_settings = {
+                address = "mail.example.com";
+                port = 25;
+              };
+            };
+          }
         '';
       };
 
@@ -186,16 +178,6 @@ in
           description = "Database user.";
         };
 
-        password = mkOption {
-          type = types.str;
-          default = "";
-          description = ''
-            The password corresponding to <option>database.user</option>.
-            Warning: this is stored in cleartext in the Nix store!
-            Use <option>database.passwordFile</option> instead.
-          '';
-        };
-
         passwordFile = mkOption {
           type = types.nullOr types.path;
           default = null;
@@ -226,11 +208,12 @@ in
     };
   };
 
+  # implementation
   config = mkIf cfg.enable {
 
     assertions = [
-      { assertion = cfg.database.passwordFile != null || cfg.database.password != "" || cfg.database.socket != null;
-        message = "one of services.redmine.database.socket, services.redmine.database.passwordFile, or services.redmine.database.password must be set";
+      { assertion = cfg.database.passwordFile != null || cfg.database.socket != null;
+        message = "one of services.redmine.database.socket or services.redmine.database.passwordFile must be set";
       }
       { assertion = cfg.database.createLocally -> cfg.database.user == cfg.user;
         message = "services.redmine.database.user must be set to ${cfg.user} if services.redmine.database.createLocally is set true";
@@ -243,6 +226,22 @@ in
       }
     ];
 
+    services.redmine.settings = {
+      production = {
+        scm_subversion_command = "${pkgs.subversion}/bin/svn";
+        scm_mercurial_command = "${pkgs.mercurial}/bin/hg";
+        scm_git_command = "${pkgs.gitAndTools.git}/bin/git";
+        scm_cvs_command = "${pkgs.cvs}/bin/cvs";
+        scm_bazaar_command = "${pkgs.breezy}/bin/bzr";
+        scm_darcs_command = "${pkgs.darcs}/bin/darcs";
+      };
+    };
+
+    services.redmine.extraEnv = mkBefore ''
+      config.logger = Logger.new("${cfg.stateDir}/log/production.log", 14, 1048576)
+      config.logger.level = Logger::INFO
+    '';
+
     services.mysql = mkIf mysqlLocal {
       enable = true;
       package = mkDefault pkgs.mariadb;
@@ -338,7 +337,7 @@ in
 
 
         # handle database.passwordFile & permissions
-        DBPASS=$(head -n1 ${cfg.database.passwordFile})
+        DBPASS=${optionalString (cfg.database.passwordFile != null) "$(head -n1 ${cfg.database.passwordFile})"}
         cp -f ${databaseYml} "${cfg.stateDir}/config/database.yml"
         sed -e "s,#dbpass#,$DBPASS,g" -i "${cfg.stateDir}/config/database.yml"
         chmod 440 "${cfg.stateDir}/config/database.yml"
@@ -379,17 +378,6 @@ in
       redmine.gid = config.ids.gids.redmine;
     };
 
-    warnings = optional (cfg.database.password != "")
-      ''config.services.redmine.database.password will be stored as plaintext
-      in the Nix store. Use database.passwordFile instead.'';
-
-    # Create database passwordFile default when password is configured.
-    services.redmine.database.passwordFile =
-      (mkDefault (toString (pkgs.writeTextFile {
-        name = "redmine-database-password";
-        text = cfg.database.password;
-      })));
-
   };
 
 }
diff --git a/nixos/modules/services/misc/siproxd.nix b/nixos/modules/services/misc/siproxd.nix
index ae7b27de8e706..0e87fc461d3fc 100644
--- a/nixos/modules/services/misc/siproxd.nix
+++ b/nixos/modules/services/misc/siproxd.nix
@@ -38,7 +38,7 @@ in
         type = types.bool;
         default = false;
         description = ''
-          Whether to enable the Siproxd SIP 
+          Whether to enable the Siproxd SIP
 	  proxy/masquerading daemon.
         '';
       };
@@ -111,7 +111,7 @@ in
         type = types.int;
         default = 300;
         description = ''
-          Timeout for an RTP stream. If for the specified 
+          Timeout for an RTP stream. If for the specified
           number of seconds no data is relayed on an active
           stream, it is considered dead and will be killed.
         '';
@@ -122,7 +122,7 @@ in
         default = 46;
         description = ''
           DSCP (differentiated services) value to be assigned
-          to RTP packets. Allows QOS aware routers to handle 
+          to RTP packets. Allows QOS aware routers to handle
           different types traffic with different priorities.
         '';
       };
@@ -132,7 +132,7 @@ in
         default = 0;
         description = ''
           DSCP (differentiated services) value to be assigned
-          to SIP packets. Allows QOS aware routers to handle 
+          to SIP packets. Allows QOS aware routers to handle
           different types traffic with different priorities.
         '';
       };
diff --git a/nixos/modules/services/misc/ssm-agent.nix b/nixos/modules/services/misc/ssm-agent.nix
index f7c05deeecb56..00e806695fd5f 100644
--- a/nixos/modules/services/misc/ssm-agent.nix
+++ b/nixos/modules/services/misc/ssm-agent.nix
@@ -29,13 +29,15 @@ in {
 
   config = mkIf cfg.enable {
     systemd.services.ssm-agent = {
+      users.extraUsers.ssm-user = {};
+
       inherit (cfg.package.meta) description;
       after    = [ "network.target" ];
       wantedBy = [ "multi-user.target" ];
 
-      path = [ fake-lsb-release ];
+      path = [ fake-lsb-release pkgs.coreutils ];
       serviceConfig = {
-        ExecStart = "${cfg.package}/bin/agent";
+        ExecStart = "${cfg.package}/bin/amazon-ssm-agent";
         KillMode = "process";
         Restart = "on-failure";
         RestartSec = "15min";
diff --git a/nixos/modules/services/misc/sssd.nix b/nixos/modules/services/misc/sssd.nix
index 3da99a3b38c1b..386281e2b7cca 100644
--- a/nixos/modules/services/misc/sssd.nix
+++ b/nixos/modules/services/misc/sssd.nix
@@ -69,7 +69,7 @@ in {
         mode = "0400";
       };
 
-      system.nssModules = pkgs.sssd;
+      system.nssModules = [ pkgs.sssd ];
       system.nssDatabases = {
         group = [ "sss" ];
         passwd = [ "sss" ];
@@ -92,4 +92,6 @@ in {
     services.openssh.authorizedKeysCommand = "/etc/ssh/authorized_keys_command";
     services.openssh.authorizedKeysCommandUser = "nobody";
   })];
+
+  meta.maintainers = with maintainers; [ bbigras ];
 }
diff --git a/nixos/modules/services/misc/tzupdate.nix b/nixos/modules/services/misc/tzupdate.nix
index 570982ced29a7..eac1e1112a5ab 100644
--- a/nixos/modules/services/misc/tzupdate.nix
+++ b/nixos/modules/services/misc/tzupdate.nix
@@ -11,7 +11,7 @@ in {
       default = false;
       description = ''
         Enable the tzupdate timezone updating service. This provides
-        a one-shot service which can be activated with systemctl to 
+        a one-shot service which can be activated with systemctl to
         update the timezone.
       '';
     };
@@ -21,7 +21,7 @@ in {
     # We need to have imperative time zone management for this to work.
     # This will give users an error if they have set an explicit time
     # zone, which is better than silently overriding it.
-    time.timeZone = null; 
+    time.timeZone = null;
 
     # We provide a one-shot service which can be manually run. We could
     # provide a service that runs on startup, but it's tricky to get
diff --git a/nixos/modules/services/misc/zigbee2mqtt.nix b/nixos/modules/services/misc/zigbee2mqtt.nix
new file mode 100644
index 0000000000000..0957920f1a097
--- /dev/null
+++ b/nixos/modules/services/misc/zigbee2mqtt.nix
@@ -0,0 +1,98 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.zigbee2mqtt;
+
+  configJSON = pkgs.writeText "configuration.json"
+    (builtins.toJSON (recursiveUpdate defaultConfig cfg.config));
+  configFile = pkgs.runCommand "configuration.yaml" { preferLocalBuild = true; } ''
+    ${pkgs.remarshal}/bin/json2yaml -i ${configJSON} -o $out
+  '';
+
+  # the default config contains all required settings,
+  # so the service starts up without crashing.
+  defaultConfig = {
+    homeassistant = false;
+    permit_join = false;
+    mqtt = {
+      base_topic = "zigbee2mqtt";
+      server = "mqtt://localhost:1883";
+    };
+    serial.port = "/dev/ttyACM0";
+    # put device configuration into separate file because configuration.yaml
+    # is copied from the store on startup
+    devices = "devices.yaml";
+  };
+in
+{
+  meta.maintainers = with maintainers; [ sweber ];
+
+  options.services.zigbee2mqtt = {
+    enable = mkEnableOption "enable zigbee2mqtt service";
+
+    package = mkOption {
+      description = "Zigbee2mqtt package to use";
+      default = pkgs.zigbee2mqtt.override {
+        dataDir = cfg.dataDir;
+      };
+      defaultText = "pkgs.zigbee2mqtt";
+      type = types.package;
+    };
+
+    dataDir = mkOption {
+      description = "Zigbee2mqtt data directory";
+      default = "/var/lib/zigbee2mqtt";
+      type = types.path;
+    };
+
+    config = mkOption {
+      default = {};
+      type = with types; nullOr attrs;
+      example = literalExample ''
+        {
+          homeassistant = config.services.home-assistant.enable;
+          permit_join = true;
+          serial = {
+            port = "/dev/ttyACM1";
+          };
+        }
+      '';
+      description = ''
+        Your <filename>configuration.yaml</filename> as a Nix attribute set.
+      '';
+    };
+  };
+
+  config = mkIf (cfg.enable) {
+    systemd.services.zigbee2mqtt = {
+      description = "Zigbee2mqtt Service";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+      serviceConfig = {
+        ExecStart = "${cfg.package}/bin/zigbee2mqtt";
+        User = "zigbee2mqtt";
+        WorkingDirectory = cfg.dataDir;
+        Restart = "on-failure";
+        ProtectSystem = "strict";
+        ReadWritePaths = cfg.dataDir;
+        PrivateTmp = true;
+        RemoveIPC = true;
+      };
+      preStart = ''
+        cp --no-preserve=mode ${configFile} "${cfg.dataDir}/configuration.yaml"
+      '';
+    };
+
+    users.users.zigbee2mqtt = {
+      home = cfg.dataDir;
+      createHome = true;
+      group = "zigbee2mqtt";
+      extraGroups = [ "dialout" ];
+      uid = config.ids.uids.zigbee2mqtt;
+    };
+
+    users.groups.zigbee2mqtt.gid = config.ids.gids.zigbee2mqtt;
+  };
+}
diff --git a/nixos/modules/services/monitoring/cadvisor.nix b/nixos/modules/services/monitoring/cadvisor.nix
index 655a6934a266f..da051dbe4655b 100644
--- a/nixos/modules/services/monitoring/cadvisor.nix
+++ b/nixos/modules/services/monitoring/cadvisor.nix
@@ -90,7 +90,7 @@ in {
         default = [];
         description = ''
           Additional cadvisor options.
-          
+
           See <link xlink:href='https://github.com/google/cadvisor/blob/master/docs/runtime_options.md'/> for available options.
         '';
       };
diff --git a/nixos/modules/services/monitoring/datadog-agent.nix b/nixos/modules/services/monitoring/datadog-agent.nix
index f1cb890794e15..673bc7b02b268 100644
--- a/nixos/modules/services/monitoring/datadog-agent.nix
+++ b/nixos/modules/services/monitoring/datadog-agent.nix
@@ -6,7 +6,7 @@ let
   cfg = config.services.datadog-agent;
 
   ddConf = {
-    dd_url              = "https://app.datadoghq.com";
+    dd_url              = cfg.ddUrl;
     skip_ssl_validation = false;
     confd_path          = "/etc/datadog-agent/conf.d";
     additional_checksd  = "/etc/datadog-agent/checks.d";
@@ -77,6 +77,18 @@ in {
       type = types.path;
     };
 
+    ddUrl = mkOption {
+      description = ''
+        Custom dd_url to configure the agent with.
+        Useful when you want to point datadog to another endpoint, either
+        because you need a proxy to send out data, or because you use their EU
+        endpoint.
+      '';
+      default = "https://app.datadoghq.com";
+      example = "https://app.datadoghq.eu";
+      type = types.str;
+    };
+
     tags = mkOption {
       description = "The tags to mark this Datadog agent";
       example = [ "test" "service" ];
diff --git a/nixos/modules/services/monitoring/dd-agent/dd-agent.nix b/nixos/modules/services/monitoring/dd-agent/dd-agent.nix
index e91717fb20547..a290dae8d4b99 100644
--- a/nixos/modules/services/monitoring/dd-agent/dd-agent.nix
+++ b/nixos/modules/services/monitoring/dd-agent/dd-agent.nix
@@ -97,11 +97,11 @@ let
         "dd-agent/conf.d/nginx.yaml".source = nginxConfig;
       }) //
       (optionalAttrs (cfg.mongoConfig != null)
-      { 
+      {
         "dd-agent/conf.d/mongo.yaml".source = mongoConfig;
       }) //
       (optionalAttrs (cfg.processConfig != null)
-      { 
+      {
         "dd-agent/conf.d/process.yaml".source = processConfig;
       }) //
       (optionalAttrs (cfg.jmxConfig != null)
diff --git a/nixos/modules/services/monitoring/do-agent.nix b/nixos/modules/services/monitoring/do-agent.nix
index 2d3fe2f797687..4dfb6236727b5 100644
--- a/nixos/modules/services/monitoring/do-agent.nix
+++ b/nixos/modules/services/monitoring/do-agent.nix
@@ -4,6 +4,7 @@ with lib;
 
 let
   cfg = config.services.do-agent;
+
 in
 {
   options.services.do-agent = {
@@ -11,23 +12,13 @@ in
   };
 
   config = mkIf cfg.enable {
-    environment.systemPackages = [ pkgs.do-agent ];
+    systemd.packages = [ pkgs.do-agent ];
 
     systemd.services.do-agent = {
-      description = "DigitalOcean Droplet Metrics Agent";
       wantedBy = [ "multi-user.target" ];
-      after = [ "network-online.target" ];
-      wants = [ "network-online.target" ];
       serviceConfig = {
-        ExecStart = "${pkgs.do-agent}/bin/do-agent --syslog";
-        Restart = "always";
-        OOMScoreAdjust = -900;
-        SyslogIdentifier = "DigitalOceanAgent";
-        PrivateTmp = "yes";
-        ProtectSystem = "full";
-        ProtectHome = "yes";
-        NoNewPrivileges = "yes";
-        DynamicUser = "yes";
+        ExecStart = [ "" "${pkgs.do-agent}/bin/do-agent --syslog" ];
+        DynamicUser = true;
       };
     };
   };
diff --git a/nixos/modules/services/monitoring/monit.nix b/nixos/modules/services/monitoring/monit.nix
index ca9352272174e..379ee967620e0 100644
--- a/nixos/modules/services/monitoring/monit.nix
+++ b/nixos/modules/services/monitoring/monit.nix
@@ -43,4 +43,6 @@ in
     };
 
   };
+
+  meta.maintainers = with maintainers; [ ryantm ];
 }
diff --git a/nixos/modules/services/monitoring/netdata.nix b/nixos/modules/services/monitoring/netdata.nix
index a5233a46e3411..2e73e15d3a867 100644
--- a/nixos/modules/services/monitoring/netdata.nix
+++ b/nixos/modules/services/monitoring/netdata.nix
@@ -133,16 +133,6 @@ in {
         }
       ];
 
-    systemd.tmpfiles.rules = [
-      "d /var/cache/netdata 0755 ${cfg.user} ${cfg.group} -"
-      "Z /var/cache/netdata - ${cfg.user} ${cfg.group} -"
-      "d /var/log/netdata 0755 ${cfg.user} ${cfg.group} -"
-      "Z /var/log/netdata - ${cfg.user} ${cfg.group} -"
-      "d /var/lib/netdata 0755 ${cfg.user} ${cfg.group} -"
-      "Z /var/lib/netdata - ${cfg.user} ${cfg.group} -"
-      "d /etc/netdata 0755 ${cfg.user} ${cfg.group} -"
-      "Z /etc/netdata - ${cfg.user} ${cfg.group} -"
-    ];
     systemd.services.netdata = {
       description = "Real time performance monitoring";
       after = [ "network.target" ];
@@ -158,11 +148,40 @@ in {
         # User and group
         User = cfg.user;
         Group = cfg.group;
-        # Runtime directory and mode
-        RuntimeDirectory = "netdata";
-        RuntimeDirectoryMode = "0755";
         # Performance
         LimitNOFILE = "30000";
+        # Runtime directory and mode
+        RuntimeDirectory = "netdata";
+        RuntimeDirectoryMode = "0750";
+        # State directory and mode
+        StateDirectory = "netdata";
+        StateDirectoryMode = "0750";
+        # Cache directory and mode
+        CacheDirectory = "netdata";
+        CacheDirectoryMode = "0750";
+        # Logs directory and mode
+        LogsDirectory = "netdata";
+        LogsDirectoryMode = "0750";
+        # Configuration directory and mode
+        ConfigurationDirectory = "netdata";
+        ConfigurationDirectoryMode = "0755";
+        # Capabilities
+        CapabilityBoundingSet = [
+          "CAP_DAC_OVERRIDE"      # is required for freeipmi and slabinfo plugins
+          "CAP_DAC_READ_SEARCH"   # is required for apps plugin
+          "CAP_FOWNER"            # is required for freeipmi plugin
+          "CAP_SETPCAP"           # is required for apps, perf and slabinfo plugins
+          "CAP_SYS_ADMIN"         # is required for perf plugin
+          "CAP_SYS_PTRACE"        # is required for apps plugin
+          "CAP_SYS_RESOURCE"      # is required for ebpf plugin
+          "CAP_NET_RAW"           # is required for fping app
+        ];
+        # Sandboxing
+        ProtectSystem = "full";
+        ProtectHome = "read-only";
+        PrivateTmp = true;
+        ProtectControlGroups = true;
+        PrivateMounts = true;
       };
     };
 
diff --git a/nixos/modules/services/monitoring/prometheus/default.nix b/nixos/modules/services/monitoring/prometheus/default.nix
index 84a72afac2f76..bfd4951ef48ad 100644
--- a/nixos/modules/services/monitoring/prometheus/default.nix
+++ b/nixos/modules/services/monitoring/prometheus/default.nix
@@ -46,7 +46,7 @@ let
   cmdlineArgs = cfg.extraFlags ++ [
     "--storage.tsdb.path=${workingDir}/data/"
     "--config.file=${prometheusYml}"
-    "--web.listen-address=${cfg.listenAddress}"
+    "--web.listen-address=${cfg.listenAddress}:${builtins.toString cfg.port}"
     "--alertmanager.notification-queue-capacity=${toString cfg.alertmanagerNotificationQueueCapacity}"
     "--alertmanager.timeout=${toString cfg.alertmanagerTimeout}s"
   ] ++
@@ -489,9 +489,17 @@ in {
       '';
     };
 
+    port = mkOption {
+      type = types.port;
+      default = 9090;
+      description = ''
+        Port to listen on.
+      '';
+    };
+
     listenAddress = mkOption {
       type = types.str;
-      default = "0.0.0.0:9090";
+      default = "0.0.0.0";
       description = ''
         Address to listen on for the web interface, API, and telemetry.
       '';
@@ -619,6 +627,23 @@ in {
   };
 
   config = mkIf cfg.enable {
+    assertions = [
+      ( let
+          # Match something with dots (an IPv4 address) or something ending in
+          # a square bracket (an IPv6 addresses) followed by a port number.
+          legacy = builtins.match "(.*\\..*|.*]):([[:digit:]]+)" cfg.listenAddress;
+        in {
+          assertion = legacy == null;
+          message = ''
+            Do not specify the port for Prometheus to listen on in the
+            listenAddress option; use the port option instead:
+              services.prometheus.listenAddress = ${builtins.elemAt legacy 0};
+              services.prometheus.port = ${builtins.elemAt legacy 1};
+          '';
+        }
+      )
+    ];
+
     users.groups.prometheus.gid = config.ids.gids.prometheus;
     users.users.prometheus = {
       description = "Prometheus daemon user";
diff --git a/nixos/modules/services/monitoring/prometheus/exporters.nix b/nixos/modules/services/monitoring/prometheus/exporters.nix
index c4aedd7e23b20..cc71451bf2067 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters.nix
@@ -34,6 +34,7 @@ let
     "mail"
     "mikrotik"
     "minio"
+    "modemmanager"
     "nextcloud"
     "nginx"
     "node"
@@ -45,6 +46,7 @@ let
     "surfboard"
     "tor"
     "unifi"
+    "unifi-poller"
     "varnish"
     "wireguard"
   ] (name:
@@ -83,7 +85,8 @@ let
     };
     firewallFilter = mkOption {
       type = types.str;
-      default = "-p tcp -m tcp --dport ${toString port}";
+      default = "-p tcp -m tcp --dport ${toString cfg.${name}.port}";
+      defaultText = "-p tcp -m tcp --dport ${toString port}";
       example = literalExample ''
         "-i eth0 -p tcp -m tcp --dport ${toString port}"
       '';
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/modemmanager.nix b/nixos/modules/services/monitoring/prometheus/exporters/modemmanager.nix
new file mode 100644
index 0000000000000..86ea98b94e4c2
--- /dev/null
+++ b/nixos/modules/services/monitoring/prometheus/exporters/modemmanager.nix
@@ -0,0 +1,33 @@
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  cfg = config.services.prometheus.exporters.modemmanager;
+in
+{
+  port = 9539;
+  extraOpts = {
+    refreshRate = mkOption {
+      type = types.str;
+      default = "5s";
+      description = ''
+        How frequently ModemManager will refresh the extended signal quality
+        information for each modem. The duration should be specified in seconds
+        ("5s"), minutes ("1m"), or hours ("1h").
+      '';
+    };
+  };
+  serviceOpts = {
+    serviceConfig = {
+      # Required in order to authenticate with ModemManager via D-Bus.
+      SupplementaryGroups = "networkmanager";
+      ExecStart = ''
+        ${pkgs.prometheus-modemmanager-exporter}/bin/modemmanager_exporter \
+          -addr ${cfg.listenAddress}:${toString cfg.port} \
+          -rate ${cfg.refreshRate} \
+          ${concatStringsSep " \\\n  " cfg.extraFlags}
+      '';
+    };
+  };
+}
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/unifi-poller.nix b/nixos/modules/services/monitoring/prometheus/exporters/unifi-poller.nix
new file mode 100644
index 0000000000000..394e6e201f03f
--- /dev/null
+++ b/nixos/modules/services/monitoring/prometheus/exporters/unifi-poller.nix
@@ -0,0 +1,34 @@
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  cfg = config.services.prometheus.exporters.unifi-poller;
+
+  configFile = pkgs.writeText "prometheus-unifi-poller-exporter.json" (generators.toJSON {} {
+    poller = { inherit (cfg.log) debug quiet; };
+    unifi = { inherit (cfg) controllers; };
+    influxdb.disable = true;
+    prometheus = {
+      http_listen = "${cfg.listenAddress}:${toString cfg.port}";
+      report_errors = cfg.log.prometheusErrors;
+    };
+  });
+
+in {
+  port = 9130;
+
+  extraOpts = {
+    inherit (options.services.unifi-poller.unifi) controllers;
+    log = {
+      debug = mkEnableOption "debug logging including line numbers, high resolution timestamps, per-device logs.";
+      quiet = mkEnableOption "startup and error logs only.";
+      prometheusErrors = mkEnableOption "emitting errors to prometheus.";
+    };
+  };
+
+  serviceOpts.serviceConfig = {
+    ExecStart = "${pkgs.unifi-poller}/bin/unifi-poller --config ${configFile}";
+    DynamicUser = false;
+  };
+}
diff --git a/nixos/modules/services/monitoring/smartd.nix b/nixos/modules/services/monitoring/smartd.nix
index c345ec48a018e..c72b4abfcdce3 100644
--- a/nixos/modules/services/monitoring/smartd.nix
+++ b/nixos/modules/services/monitoring/smartd.nix
@@ -18,9 +18,9 @@ let
     ${optionalString nm.enable ''
       {
       ${pkgs.coreutils}/bin/cat << EOF
-      From: smartd on ${host} <root>
+      From: smartd on ${host} <${nm.sender}>
       To: undisclosed-recipients:;
-      Subject: SMART error on $SMARTD_DEVICESTRING: $SMARTD_FAILTYPE
+      Subject: $SMARTD_SUBJECT
 
       $SMARTD_FULLMESSAGE
       EOF
@@ -129,6 +129,16 @@ in
             description = "Whenever to send e-mail notifications.";
           };
 
+          sender = mkOption {
+            default = "root";
+            example = "example@domain.tld";
+            type = types.str;
+            description = ''
+              Sender of the notification messages.
+              Acts as the value of <literal>email</literal> in the emails' <literal>From: ... </literal> field.
+            '';
+          };
+
           recipient = mkOption {
             default = "root";
             type = types.str;
@@ -229,11 +239,7 @@ in
 
     systemd.services.smartd = {
       description = "S.M.A.R.T. Daemon";
-
       wantedBy = [ "multi-user.target" ];
-
-      path = [ pkgs.nettools ]; # for hostname and dnsdomanname calls in smartd
-
       serviceConfig.ExecStart = "${pkgs.smartmontools}/sbin/smartd ${lib.concatStringsSep " " cfg.extraOptions} --no-fork --configfile=${smartdConf}";
     };
 
diff --git a/nixos/modules/services/monitoring/teamviewer.nix b/nixos/modules/services/monitoring/teamviewer.nix
index dd98ecab828d7..8d781d82d0864 100644
--- a/nixos/modules/services/monitoring/teamviewer.nix
+++ b/nixos/modules/services/monitoring/teamviewer.nix
@@ -15,7 +15,7 @@ in
   options = {
 
     services.teamviewer.enable = mkEnableOption "TeamViewer daemon";
-      
+
   };
 
   ###### implementation
diff --git a/nixos/modules/services/monitoring/unifi-poller.nix b/nixos/modules/services/monitoring/unifi-poller.nix
new file mode 100644
index 0000000000000..208f5e4875b40
--- /dev/null
+++ b/nixos/modules/services/monitoring/unifi-poller.nix
@@ -0,0 +1,242 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.unifi-poller;
+
+  configFile = pkgs.writeText "unifi-poller.json" (generators.toJSON {} {
+    inherit (cfg) poller influxdb prometheus unifi;
+  });
+
+in {
+  options.services.unifi-poller = {
+    enable = mkEnableOption "unifi-poller";
+
+    poller = {
+      debug = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Turns on line numbers, microsecond logging, and a per-device log.
+          This may be noisy if you have a lot of devices. It adds one line per device.
+        '';
+      };
+      quiet = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Turns off per-interval logs. Only startup and error logs will be emitted.
+        '';
+      };
+      plugins = mkOption {
+        type = with types; listOf str;
+        default = [];
+        description = ''
+          Load additional plugins.
+        '';
+      };
+    };
+
+    prometheus = {
+      disable = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to disable the prometheus ouput plugin.
+        '';
+      };
+      http_listen = mkOption {
+        type = types.str;
+        default = "[::]:9130";
+        description = ''
+          Bind the prometheus exporter to this IP or hostname.
+        '';
+      };
+      report_errors = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to report errors.
+        '';
+      };
+    };
+
+    influxdb = {
+      disable = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to disable the influxdb ouput plugin.
+        '';
+      };
+      url = mkOption {
+        type = types.str;
+        default = "http://127.0.0.1:8086";
+        description = ''
+          URL of the influxdb host.
+        '';
+      };
+      user = mkOption {
+        type = types.str;
+        default = "unifipoller";
+        description = ''
+          Username for the influxdb.
+        '';
+      };
+      pass = mkOption {
+        type = types.path;
+        default = pkgs.writeText "unifi-poller-influxdb-default.password" "unifipoller";
+        defaultText = "unifi-poller-influxdb-default.password";
+        description = ''
+          Path of a file containing the password for influxdb.
+          This file needs to be readable by the unifi-poller user.
+        '';
+        apply = v: "file://${v}";
+      };
+      db = mkOption {
+        type = types.str;
+        default = "unifi";
+        description = ''
+          Database name. Database should exist.
+        '';
+      };
+      verify_ssl = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          Verify the influxdb's certificate.
+        '';
+      };
+      interval = mkOption {
+        type = types.str;
+        default = "30s";
+        description = ''
+          Setting this lower than the Unifi controller's refresh
+          interval may lead to zeroes in your database.
+        '';
+      };
+    };
+
+    unifi = let
+      controllerOptions = {
+        user = mkOption {
+          type = types.str;
+          default = "unifi";
+          description = ''
+            Unifi service user name.
+          '';
+        };
+        pass = mkOption {
+          type = types.path;
+          default = pkgs.writeText "unifi-poller-unifi-default.password" "unifi";
+          defaultText = "unifi-poller-unifi-default.password";
+          description = ''
+            Path of a file containing the password for the unifi service user.
+            This file needs to be readable by the unifi-poller user.
+          '';
+          apply = v: "file://${v}";
+        };
+        url = mkOption {
+          type = types.str;
+          default = "https://unifi:8443";
+          description = ''
+            URL of the Unifi controller.
+          '';
+        };
+        sites = mkOption {
+          type = with types; either (enum [ "default" "all" ]) (listOf str);
+          default = "all";
+          description = ''
+            List of site names for which statistics should be exported.
+            Or the string "default" for the default site or the string "all" for all sites.
+          '';
+          apply = toList;
+        };
+        save_ids = mkOption {
+          type = types.bool;
+          default = false;
+          description = ''
+            Collect and save data from the intrusion detection system to influxdb.
+          '';
+        };
+        save_dpi = mkOption {
+          type = types.bool;
+          default = false;
+          description = ''
+            Collect and save data from deep packet inspection.
+            Adds around 150 data points and impacts performance.
+          '';
+        };
+        save_sites = mkOption {
+          type = types.bool;
+          default = true;
+          description = ''
+            Collect and save site data.
+          '';
+        };
+        hash_pii = mkOption {
+          type = types.bool;
+          default = false;
+          description = ''
+            Hash, with md5, client names and MAC addresses. This attempts
+            to protect personally identifiable information.
+          '';
+        };
+        verify_ssl = mkOption {
+          type = types.bool;
+          default = true;
+          description = ''
+            Verify the Unifi controller's certificate.
+          '';
+        };
+      };
+
+    in {
+      dynamic = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Let prometheus select which controller to poll when scraping.
+          Use with default credentials. See unifi-poller wiki for more.
+        '';
+      };
+
+      defaults = controllerOptions;
+
+      controllers = mkOption {
+        type = with types; listOf (submodule { options = controllerOptions; });
+        default = [];
+        description = ''
+          List of Unifi controllers to poll. Use defaults if empty.
+        '';
+        apply = map (flip removeAttrs [ "_module" ]);
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    users.groups.unifi-poller = { };
+    users.users.unifi-poller = {
+      description = "unifi-poller Service User";
+      group = "unifi-poller";
+      isSystemUser = true;
+    };
+
+    systemd.services.unifi-poller = {
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+      serviceConfig = {
+        ExecStart = "${pkgs.unifi-poller}/bin/unifi-poller --config ${configFile}";
+        Restart = "always";
+        PrivateTmp = true;
+        ProtectHome = true;
+        ProtectSystem = "full";
+        DevicePolicy = "closed";
+        NoNewPrivileges = true;
+        User = "unifi-poller";
+        WorkingDirectory = "/tmp";
+      };
+    };
+  };
+}
diff --git a/nixos/modules/services/monitoring/zabbix-agent.nix b/nixos/modules/services/monitoring/zabbix-agent.nix
index b3383ed628b29..73eed7aa66af3 100644
--- a/nixos/modules/services/monitoring/zabbix-agent.nix
+++ b/nixos/modules/services/monitoring/zabbix-agent.nix
@@ -3,8 +3,9 @@
 let
   cfg = config.services.zabbixAgent;
 
-  inherit (lib) mkDefault mkEnableOption mkIf mkOption;
+  inherit (lib) mkDefault mkEnableOption mkIf mkMerge mkOption;
   inherit (lib) attrValues concatMapStringsSep literalExample optionalString types;
+  inherit (lib.generators) toKeyValue;
 
   user = "zabbix-agent";
   group = "zabbix-agent";
@@ -14,19 +15,15 @@ let
     paths = attrValues cfg.modules;
   };
 
-  configFile = pkgs.writeText "zabbix_agent.conf" ''
-    LogType = console
-    Server = ${cfg.server}
-    ListenIP = ${cfg.listen.ip}
-    ListenPort = ${toString cfg.listen.port}
-    ${optionalString (cfg.modules != {}) "LoadModulePath = ${moduleEnv}/lib"}
-    ${concatMapStringsSep "\n" (name: "LoadModule = ${name}") (builtins.attrNames cfg.modules)}
-    ${cfg.extraConfig}
-  '';
+  configFile = pkgs.writeText "zabbix_agent.conf" (toKeyValue { listsAsDuplicateKeys = true; } cfg.settings);
 
 in
 
 {
+  imports = [
+    (lib.mkRemovedOptionModule [ "services" "zabbixAgent" "extraConfig" ] "Use services.zabbixAgent.settings instead.")
+  ];
+
   # interface
 
   options = {
@@ -105,15 +102,18 @@ in
         '';
       };
 
-      # TODO: for bonus points migrate this to https://github.com/NixOS/rfcs/pull/42
-      extraConfig = mkOption {
-        default = "";
-        type = types.lines;
+      settings = mkOption {
+        type = with types; attrsOf (oneOf [ int str (listOf str) ]);
+        default = {};
         description = ''
-          Configuration that is injected verbatim into the configuration file. Refer to
+          Zabbix Agent configuration. Refer to
           <link xlink:href="https://www.zabbix.com/documentation/current/manual/appendix/config/zabbix_agentd"/>
           for details on supported values.
         '';
+        example = {
+          Hostname = "example.org";
+          DebugLevel = 4;
+        };
       };
 
     };
@@ -124,6 +124,17 @@ in
 
   config = mkIf cfg.enable {
 
+    services.zabbixAgent.settings = mkMerge [
+      {
+        LogType = "console";
+        Server = cfg.server;
+        ListenIP = cfg.listen.ip;
+        ListenPort = cfg.listen.port;
+        LoadModule = builtins.attrNames cfg.modules;
+      }
+      (mkIf (cfg.modules != {}) { LoadModulePath = "${moduleEnv}/lib"; })
+    ];
+
     networking.firewall = mkIf cfg.openFirewall {
       allowedTCPPorts = [ cfg.listen.port ];
     };
diff --git a/nixos/modules/services/monitoring/zabbix-proxy.nix b/nixos/modules/services/monitoring/zabbix-proxy.nix
index 9d214469c3b32..2c8b8b92cb38b 100644
--- a/nixos/modules/services/monitoring/zabbix-proxy.nix
+++ b/nixos/modules/services/monitoring/zabbix-proxy.nix
@@ -5,8 +5,9 @@ let
   pgsql = config.services.postgresql;
   mysql = config.services.mysql;
 
-  inherit (lib) mkDefault mkEnableOption mkIf mkOption;
-  inherit (lib) attrValues concatMapStringsSep literalExample optional optionalAttrs optionalString types;
+  inherit (lib) mkAfter mkDefault mkEnableOption mkIf mkMerge mkOption;
+  inherit (lib) attrValues concatMapStringsSep getName literalExample optional optionalAttrs optionalString types;
+  inherit (lib.generators) toKeyValue;
 
   user = "zabbix";
   group = "zabbix";
@@ -19,24 +20,7 @@ let
     paths = attrValues cfg.modules;
   };
 
-  configFile = pkgs.writeText "zabbix_proxy.conf" ''
-    LogType = console
-    ListenIP = ${cfg.listen.ip}
-    ListenPort = ${toString cfg.listen.port}
-    Server = ${cfg.server}
-    # TODO: set to cfg.database.socket if database type is pgsql?
-    DBHost = ${optionalString (cfg.database.createLocally != true) cfg.database.host}
-    ${optionalString (cfg.database.createLocally != true) "DBPort = ${cfg.database.port}"}
-    DBName = ${cfg.database.name}
-    DBUser = ${cfg.database.user}
-    ${optionalString (cfg.database.passwordFile != null) "Include ${passwordFile}"}
-    ${optionalString (mysqlLocal && cfg.database.socket != null) "DBSocket = ${cfg.database.socket}"}
-    SocketDir = ${runtimeDir}
-    FpingLocation = /run/wrappers/bin/fping
-    ${optionalString (cfg.modules != {}) "LoadModulePath = ${moduleEnv}/lib"}
-    ${concatMapStringsSep "\n" (name: "LoadModule = ${name}") (builtins.attrNames cfg.modules)}
-    ${cfg.extraConfig}
-  '';
+  configFile = pkgs.writeText "zabbix_proxy.conf" (toKeyValue { listsAsDuplicateKeys = true; } cfg.settings);
 
   mysqlLocal = cfg.database.createLocally && cfg.database.type == "mysql";
   pgsqlLocal = cfg.database.createLocally && cfg.database.type == "pgsql";
@@ -44,6 +28,10 @@ let
 in
 
 {
+  imports = [
+    (lib.mkRemovedOptionModule [ "services" "zabbixProxy" "extraConfig" ] "Use services.zabbixProxy.settings instead.")
+  ];
+
   # interface
 
   options = {
@@ -182,15 +170,19 @@ in
         '';
       };
 
-      # TODO: for bonus points migrate this to https://github.com/NixOS/rfcs/pull/42
-      extraConfig = mkOption {
-        default = "";
-        type = types.lines;
+      settings = mkOption {
+        type = with types; attrsOf (oneOf [ int str (listOf str) ]);
+        default = {};
         description = ''
-          Configuration that is injected verbatim into the configuration file. Refer to
+          Zabbix Proxy configuration. Refer to
           <link xlink:href="https://www.zabbix.com/documentation/current/manual/appendix/config/zabbix_proxy"/>
           for details on supported values.
         '';
+        example = {
+          CacheSize = "1G";
+          SSHKeyLocation = "/var/lib/zabbix/.ssh";
+          StartPingers = 32;
+        };
       };
 
     };
@@ -213,6 +205,26 @@ in
       }
     ];
 
+    services.zabbixProxy.settings = mkMerge [
+      {
+        LogType = "console";
+        ListenIP = cfg.listen.ip;
+        ListenPort = cfg.listen.port;
+        Server = cfg.server;
+        # TODO: set to cfg.database.socket if database type is pgsql?
+        DBHost = optionalString (cfg.database.createLocally != true) cfg.database.host;
+        DBName = cfg.database.name;
+        DBUser = cfg.database.user;
+        SocketDir = runtimeDir;
+        FpingLocation = "/run/wrappers/bin/fping";
+        LoadModule = builtins.attrNames cfg.modules;
+      }
+      (mkIf (cfg.database.createLocally != true) { DBPort = cfg.database.port; })
+      (mkIf (cfg.database.passwordFile != null) { Include = [ "${passwordFile}" ]; })
+      (mkIf (mysqlLocal && cfg.database.socket != null) { DBSocket = cfg.database.socket; })
+      (mkIf (cfg.modules != {}) { LoadModulePath = "${moduleEnv}/lib"; })
+    ];
+
     networking.firewall = mkIf cfg.openFirewall {
       allowedTCPPorts = [ cfg.listen.port ];
     };
@@ -220,14 +232,15 @@ in
     services.mysql = optionalAttrs mysqlLocal {
       enable = true;
       package = mkDefault pkgs.mariadb;
-      ensureDatabases = [ cfg.database.name ];
-      ensureUsers = [
-        { name = cfg.database.user;
-          ensurePermissions = { "${cfg.database.name}.*" = "ALL PRIVILEGES"; };
-        }
-      ];
     };
 
+    systemd.services.mysql.postStart = mkAfter (optionalString mysqlLocal ''
+      ( echo "CREATE DATABASE IF NOT EXISTS \`${cfg.database.name}\` CHARACTER SET utf8 COLLATE utf8_bin;"
+        echo "CREATE USER IF NOT EXISTS '${cfg.database.user}'@'localhost' IDENTIFIED WITH ${if (getName config.services.mysql.package == getName pkgs.mariadb) then "unix_socket" else "auth_socket"};"
+        echo "GRANT ALL PRIVILEGES ON \`${cfg.database.name}\`.* TO '${cfg.database.user}'@'localhost';"
+      ) | ${config.services.mysql.package}/bin/mysql -N
+    '');
+
     services.postgresql = optionalAttrs pgsqlLocal {
       enable = true;
       ensureDatabases = [ cfg.database.name ];
diff --git a/nixos/modules/services/monitoring/zabbix-server.nix b/nixos/modules/services/monitoring/zabbix-server.nix
index b4e4378ce1e76..c8658634ecb62 100644
--- a/nixos/modules/services/monitoring/zabbix-server.nix
+++ b/nixos/modules/services/monitoring/zabbix-server.nix
@@ -5,8 +5,9 @@ let
   pgsql = config.services.postgresql;
   mysql = config.services.mysql;
 
-  inherit (lib) mkDefault mkEnableOption mkIf mkOption;
-  inherit (lib) attrValues concatMapStringsSep literalExample optional optionalAttrs optionalString types;
+  inherit (lib) mkAfter mkDefault mkEnableOption mkIf mkMerge mkOption;
+  inherit (lib) attrValues concatMapStringsSep getName literalExample optional optionalAttrs optionalString types;
+  inherit (lib.generators) toKeyValue;
 
   user = "zabbix";
   group = "zabbix";
@@ -19,24 +20,7 @@ let
     paths = attrValues cfg.modules;
   };
 
-  configFile = pkgs.writeText "zabbix_server.conf" ''
-    LogType = console
-    ListenIP = ${cfg.listen.ip}
-    ListenPort = ${toString cfg.listen.port}
-    # TODO: set to cfg.database.socket if database type is pgsql?
-    DBHost = ${optionalString (cfg.database.createLocally != true) cfg.database.host}
-    ${optionalString (cfg.database.createLocally != true) "DBPort = ${cfg.database.port}"}
-    DBName = ${cfg.database.name}
-    DBUser = ${cfg.database.user}
-    ${optionalString (cfg.database.passwordFile != null) "Include ${passwordFile}"}
-    ${optionalString (mysqlLocal && cfg.database.socket != null) "DBSocket = ${cfg.database.socket}"}
-    PidFile = ${runtimeDir}/zabbix_server.pid
-    SocketDir = ${runtimeDir}
-    FpingLocation = /run/wrappers/bin/fping
-    ${optionalString (cfg.modules != {}) "LoadModulePath = ${moduleEnv}/lib"}
-    ${concatMapStringsSep "\n" (name: "LoadModule = ${name}") (builtins.attrNames cfg.modules)}
-    ${cfg.extraConfig}
-  '';
+  configFile = pkgs.writeText "zabbix_server.conf" (toKeyValue { listsAsDuplicateKeys = true; } cfg.settings);
 
   mysqlLocal = cfg.database.createLocally && cfg.database.type == "mysql";
   pgsqlLocal = cfg.database.createLocally && cfg.database.type == "pgsql";
@@ -47,6 +31,7 @@ in
   imports = [
     (lib.mkRenamedOptionModule [ "services" "zabbixServer" "dbServer" ] [ "services" "zabbixServer" "database" "host" ])
     (lib.mkRemovedOptionModule [ "services" "zabbixServer" "dbPassword" ] "Use services.zabbixServer.database.passwordFile instead.")
+    (lib.mkRemovedOptionModule [ "services" "zabbixServer" "extraConfig" ] "Use services.zabbixServer.settings instead.")
   ];
 
   # interface
@@ -176,15 +161,19 @@ in
         '';
       };
 
-      # TODO: for bonus points migrate this to https://github.com/NixOS/rfcs/pull/42
-      extraConfig = mkOption {
-        default = "";
-        type = types.lines;
+      settings = mkOption {
+        type = with types; attrsOf (oneOf [ int str (listOf str) ]);
+        default = {};
         description = ''
-          Configuration that is injected verbatim into the configuration file. Refer to
+          Zabbix Server configuration. Refer to
           <link xlink:href="https://www.zabbix.com/documentation/current/manual/appendix/config/zabbix_server"/>
           for details on supported values.
         '';
+        example = {
+          CacheSize = "1G";
+          SSHKeyLocation = "/var/lib/zabbix/.ssh";
+          StartPingers = 32;
+        };
       };
 
     };
@@ -204,6 +193,26 @@ in
       }
     ];
 
+    services.zabbixServer.settings = mkMerge [
+      {
+        LogType = "console";
+        ListenIP = cfg.listen.ip;
+        ListenPort = cfg.listen.port;
+        # TODO: set to cfg.database.socket if database type is pgsql?
+        DBHost = optionalString (cfg.database.createLocally != true) cfg.database.host;
+        DBName = cfg.database.name;
+        DBUser = cfg.database.user;
+        PidFile = "${runtimeDir}/zabbix_server.pid";
+        SocketDir = runtimeDir;
+        FpingLocation = "/run/wrappers/bin/fping";
+        LoadModule = builtins.attrNames cfg.modules;
+      }
+      (mkIf (cfg.database.createLocally != true) { DBPort = cfg.database.port; })
+      (mkIf (cfg.database.passwordFile != null) { Include = [ "${passwordFile}" ]; })
+      (mkIf (mysqlLocal && cfg.database.socket != null) { DBSocket = cfg.database.socket; })
+      (mkIf (cfg.modules != {}) { LoadModulePath = "${moduleEnv}/lib"; })
+    ];
+
     networking.firewall = mkIf cfg.openFirewall {
       allowedTCPPorts = [ cfg.listen.port ];
     };
@@ -211,14 +220,15 @@ in
     services.mysql = optionalAttrs mysqlLocal {
       enable = true;
       package = mkDefault pkgs.mariadb;
-      ensureDatabases = [ cfg.database.name ];
-      ensureUsers = [
-        { name = cfg.database.user;
-          ensurePermissions = { "${cfg.database.name}.*" = "ALL PRIVILEGES"; };
-        }
-      ];
     };
 
+    systemd.services.mysql.postStart = mkAfter (optionalString mysqlLocal ''
+      ( echo "CREATE DATABASE IF NOT EXISTS \`${cfg.database.name}\` CHARACTER SET utf8 COLLATE utf8_bin;"
+        echo "CREATE USER IF NOT EXISTS '${cfg.database.user}'@'localhost' IDENTIFIED WITH ${if (getName config.services.mysql.package == getName pkgs.mariadb) then "unix_socket" else "auth_socket"};"
+        echo "GRANT ALL PRIVILEGES ON \`${cfg.database.name}\`.* TO '${cfg.database.user}'@'localhost';"
+      ) | ${config.services.mysql.package}/bin/mysql -N
+    '');
+
     services.postgresql = optionalAttrs pgsqlLocal {
       enable = true;
       ensureDatabases = [ cfg.database.name ];
diff --git a/nixos/modules/services/network-filesystems/cachefilesd.nix b/nixos/modules/services/network-filesystems/cachefilesd.nix
index 619813408405f..229c9665419f5 100644
--- a/nixos/modules/services/network-filesystems/cachefilesd.nix
+++ b/nixos/modules/services/network-filesystems/cachefilesd.nix
@@ -43,17 +43,21 @@ in
 
   config = mkIf cfg.enable {
 
+    boot.kernelModules = [ "cachefiles" ];
+
     systemd.services.cachefilesd = {
       description = "Local network file caching management daemon";
       wantedBy = [ "multi-user.target" ];
-      path = [ pkgs.kmod pkgs.cachefilesd ];
-      script = ''
-        modprobe -qab cachefiles
-        mkdir -p ${cfg.cacheDir}
-        chmod 700 ${cfg.cacheDir}
-        exec cachefilesd -n -f ${cfgFile}
-      '';
+      serviceConfig = {
+        Type = "exec";
+        ExecStart = "${pkgs.cachefilesd}/bin/cachefilesd -n -f ${cfgFile}";
+        Restart = "on-failure";
+        PrivateTmp = true;
+      };
     };
 
+    systemd.tmpfiles.rules = [
+      "d ${cfg.cacheDir} 0700 root root - -"
+    ];
   };
 }
diff --git a/nixos/modules/services/network-filesystems/ipfs.nix b/nixos/modules/services/network-filesystems/ipfs.nix
index 7d18410ff0a45..f298f831fa7b2 100644
--- a/nixos/modules/services/network-filesystems/ipfs.nix
+++ b/nixos/modules/services/network-filesystems/ipfs.nix
@@ -25,6 +25,15 @@ let
       then "/${lib.concatStringsSep "/" (lib.tail addr)}"
     else null; # not valid for listen stream, skip
 
+  multiaddrToListenDatagram = addrRaw: let
+      addr = splitMulitaddr addrRaw;
+      s = builtins.elemAt addr;
+    in if s 0 == "ip4" && s 2 == "udp"
+      then "${s 1}:${s 3}"
+    else if s 0 == "ip6" && s 2 == "udp"
+      then "[${s 1}]:${s 3}"
+    else null; # not valid for listen datagram, skip
+
 in {
 
   ###### interface
@@ -96,6 +105,8 @@ in {
         default = [
           "/ip4/0.0.0.0/tcp/4001"
           "/ip6/::/tcp/4001"
+          "/ip4/0.0.0.0/udp/4001/quic"
+          "/ip6/::/udp/4001/quic"
         ];
         description = "Where IPFS listens for incoming p2p connections";
       };
@@ -266,9 +277,14 @@ in {
 
     systemd.sockets.ipfs-gateway = {
       wantedBy = [ "sockets.target" ];
-      socketConfig.ListenStream = let
-          fromCfg = multiaddrToListenStream cfg.gatewayAddress;
-        in [ "" ] ++ lib.optional (fromCfg != null) fromCfg;
+      socketConfig = {
+        ListenStream = let
+            fromCfg = multiaddrToListenStream cfg.gatewayAddress;
+          in [ "" ] ++ lib.optional (fromCfg != null) fromCfg;
+        ListenDatagram = let
+            fromCfg = multiaddrToListenDatagram cfg.gatewayAddress;
+          in [ "" ] ++ lib.optional (fromCfg != null) fromCfg;
+      };
     };
 
     systemd.sockets.ipfs-api = {
diff --git a/nixos/modules/services/network-filesystems/orangefs/server.nix b/nixos/modules/services/network-filesystems/orangefs/server.nix
index 74ebdc1340245..8eb754fe61103 100644
--- a/nixos/modules/services/network-filesystems/orangefs/server.nix
+++ b/nixos/modules/services/network-filesystems/orangefs/server.nix
@@ -83,14 +83,14 @@ in {
       };
 
       dataStorageSpace = mkOption {
-        type = types.str;
+        type = types.nullOr types.str;
         default = null;
         example = "/data/storage";
         description = "Directory for data storage.";
       };
 
       metadataStorageSpace = mkOption {
-        type = types.str;
+        type = types.nullOr types.str;
         default = null;
         example = "/data/meta";
         description = "Directory for meta data storage.";
diff --git a/nixos/modules/services/network-filesystems/samba.nix b/nixos/modules/services/network-filesystems/samba.nix
index 08c912e0fcd43..7d3c601d6cd5f 100644
--- a/nixos/modules/services/network-filesystems/samba.nix
+++ b/nixos/modules/services/network-filesystems/samba.nix
@@ -248,7 +248,7 @@ in
         };
 
         security.pam.services.samba = {};
-
+        environment.systemPackages = [ config.services.samba.package ];
       })
     ];
 
diff --git a/nixos/modules/services/networking/3proxy.nix b/nixos/modules/services/networking/3proxy.nix
index ae8a4958ca965..37a48657c1cc9 100644
--- a/nixos/modules/services/networking/3proxy.nix
+++ b/nixos/modules/services/networking/3proxy.nix
@@ -124,7 +124,7 @@ in {
                   <literal>"iponly"</literal>: specifies no authentication. ACLs authorization is used.
                 </para></listitem>
                 <listitem><para>
-                  <literal>"strong"</literal>: authentication by username/password. If user is not registered his access is denied regardless of ACLs.
+                  <literal>"strong"</literal>: authentication by username/password. If user is not registered their access is denied regardless of ACLs.
                 </para></listitem>
               </itemizedlist>
 
diff --git a/nixos/modules/services/networking/biboumi.nix b/nixos/modules/services/networking/biboumi.nix
new file mode 100644
index 0000000000000..66ddca93d8181
--- /dev/null
+++ b/nixos/modules/services/networking/biboumi.nix
@@ -0,0 +1,269 @@
+{ config, lib, pkgs, options, ... }:
+with lib;
+let
+  cfg = config.services.biboumi;
+  inherit (config.environment) etc;
+  rootDir = "/run/biboumi/mnt-root";
+  stateDir = "/var/lib/biboumi";
+  settingsFile = pkgs.writeText "biboumi.cfg" (
+    generators.toKeyValue {
+      mkKeyValue = k: v:
+        if v == null then ""
+        else generators.mkKeyValueDefault {} "=" k v;
+    } cfg.settings);
+  need_CAP_NET_BIND_SERVICE = cfg.settings.identd_port != 0 && cfg.settings.identd_port < 1024;
+in
+{
+  options = {
+    services.biboumi = {
+      enable = mkEnableOption "the Biboumi XMPP gateway to IRC";
+
+      settings = mkOption {
+        description = ''
+          See <link xlink:href="https://lab.louiz.org/louiz/biboumi/blob/8.5/doc/biboumi.1.rst">biboumi 8.5</link>
+          for documentation.
+        '';
+        default = {};
+        type = types.submodule {
+          freeformType = with types;
+            (attrsOf (nullOr (oneOf [str int bool]))) // {
+              description = "settings option";
+            };
+          options.admin = mkOption {
+            type = with types; listOf str;
+            default = [];
+            example = ["admin@example.org"];
+            apply = concatStringsSep ":";
+            description = ''
+              The bare JID of the gateway administrator. This JID will have more
+              privileges than other standard users, for example some administration
+              ad-hoc commands will only be available to that JID.
+            '';
+          };
+          options.ca_file = mkOption {
+            type = types.path;
+            default = "/etc/ssl/certs/ca-certificates.crt";
+            description = ''
+              Specifies which file should be used as the list of trusted CA
+              when negociating a TLS session.
+            '';
+          };
+          options.db_name = mkOption {
+            type = with types; either path str;
+            default = "${stateDir}/biboumi.sqlite";
+            description = ''
+              The name of the database to use.
+            '';
+            example = "postgresql://user:secret@localhost";
+          };
+          options.hostname = mkOption {
+            type = types.str;
+            example = "biboumi.example.org";
+            description = ''
+              The hostname served by the XMPP gateway.
+              This domain must be configured in the XMPP server
+              as an external component.
+            '';
+          };
+          options.identd_port = mkOption {
+            type = types.port;
+            default = 113;
+            example = 0;
+            description = ''
+              The TCP port on which to listen for identd queries.
+            '';
+          };
+          options.log_level = mkOption {
+            type = types.ints.between 0 3;
+            default = 1;
+            description = ''
+              Indicate what type of log messages to write in the logs.
+              0 is debug, 1 is info, 2 is warning, 3 is error.
+            '';
+          };
+          options.password = mkOption {
+            type = with types; nullOr str;
+            description = ''
+              The password used to authenticate the XMPP component to your XMPP server.
+              This password must be configured in the XMPP server,
+              associated with the external component on
+              <link linkend="opt-services.biboumi.settings.hostname">hostname</link>.
+
+              Set it to null and use <link linkend="opt-services.biboumi.credentialsFile">credentialsFile</link>
+              if you do not want this password to go into the Nix store.
+            '';
+          };
+          options.persistent_by_default = mkOption {
+            type = types.bool;
+            default = false;
+            description = ''
+              Whether all rooms will be persistent by default:
+              the value of the “persistent” option in the global configuration of each
+              user will be “true”, but the value of each individual room will still
+              default to false. This means that a user just needs to change the global
+              “persistent” configuration option to false in order to override this.
+            '';
+          };
+          options.policy_directory = mkOption {
+            type = types.path;
+            default = "${pkgs.biboumi}/etc/biboumi";
+            description = ''
+              A directory that should contain the policy files,
+              used to customize Botan’s behaviour
+              when negociating the TLS connections with the IRC servers.
+            '';
+          };
+          options.port = mkOption {
+            type = types.port;
+            default = 5347;
+            description = ''
+              The TCP port to use to connect to the local XMPP component.
+            '';
+          };
+          options.realname_customization = mkOption {
+            type = types.bool;
+            default = true;
+            description = ''
+              Whether the users will be able to use
+              the ad-hoc commands that lets them configure
+              their realname and username.
+            '';
+          };
+          options.realname_from_jid = mkOption {
+            type = types.bool;
+            default = false;
+            description = ''
+              Whether the realname and username of each biboumi
+              user will be extracted from their JID.
+              Otherwise they will be set to the nick
+              they used to connect to the IRC server.
+            '';
+          };
+          options.xmpp_server_ip = mkOption {
+            type = types.str;
+            default = "127.0.0.1";
+            description = ''
+              The IP address to connect to the XMPP server on.
+              The connection to the XMPP server is unencrypted,
+              so the biboumi instance and the server should
+              normally be on the same host.
+            '';
+          };
+        };
+      };
+
+      credentialsFile = mkOption {
+        type = types.path;
+        description = ''
+          Path to a configuration file to be merged with the settings.
+          Beware not to surround "=" with spaces when setting biboumi's options in this file.
+          Useful to merge a file which is better kept out of the Nix store
+          because it contains sensible data like
+          <link linkend="opt-services.biboumi.settings.password">password</link>.
+        '';
+        default = "/dev/null";
+        example = "/run/keys/biboumi.cfg";
+      };
+
+      openFirewall = mkEnableOption "opening of the identd port in the firewall";
+    };
+  };
+
+  config = mkIf cfg.enable {
+    networking.firewall = mkIf (cfg.openFirewall && cfg.settings.identd_port != 0)
+      { allowedTCPPorts = [ cfg.settings.identd_port ]; };
+
+    systemd.services.biboumi = {
+      description = "Biboumi, XMPP to IRC gateway";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+
+      serviceConfig = {
+        Type = "notify";
+        # Biboumi supports systemd's watchdog.
+        WatchdogSec = 20;
+        Restart = "always";
+        # Use "+" because credentialsFile may not be accessible to User= or Group=.
+        ExecStartPre = [("+" + pkgs.writeShellScript "biboumi-prestart" ''
+          set -eux
+          cat ${settingsFile} '${cfg.credentialsFile}' |
+          install -m 644 /dev/stdin /run/biboumi/biboumi.cfg
+        '')];
+        ExecStart = "${pkgs.biboumi}/bin/biboumi /run/biboumi/biboumi.cfg";
+        ExecReload = "${pkgs.coreutils}/bin/kill -USR1 $MAINPID";
+        # Firewalls needing opening for output connections can still do that
+        # selectively for biboumi with:
+        # users.users.biboumi.isSystemUser = true;
+        # and, for example:
+        # networking.nftables.ruleset = ''
+        #   add rule inet filter output meta skuid biboumi tcp accept
+        # '';
+        DynamicUser = true;
+        RootDirectory = rootDir;
+        RootDirectoryStartOnly = true;
+        InaccessiblePaths = [ "-+${rootDir}" ];
+        RuntimeDirectory = [ "biboumi" (removePrefix "/run/" rootDir) ];
+        RuntimeDirectoryMode = "700";
+        StateDirectory = "biboumi";
+        StateDirectoryMode = "700";
+        MountAPIVFS = true;
+        UMask = "0066";
+        BindPaths = [
+          stateDir
+          # This is for Type="notify"
+          # See https://github.com/systemd/systemd/issues/3544
+          "/run/systemd/notify"
+          "/run/systemd/journal/socket"
+        ];
+        BindReadOnlyPaths = [
+          builtins.storeDir
+          "/etc"
+        ];
+        # The following options are only for optimizing:
+        # systemd-analyze security biboumi
+        AmbientCapabilities = [ (optionalString need_CAP_NET_BIND_SERVICE "CAP_NET_BIND_SERVICE") ];
+        CapabilityBoundingSet = [ (optionalString need_CAP_NET_BIND_SERVICE "CAP_NET_BIND_SERVICE") ];
+        # ProtectClock= adds DeviceAllow=char-rtc r
+        DeviceAllow = "";
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        NoNewPrivileges = true;
+        PrivateDevices = true;
+        PrivateMounts = true;
+        PrivateNetwork = mkDefault false;
+        PrivateTmp = true;
+        # PrivateUsers=true breaks AmbientCapabilities=CAP_NET_BIND_SERVICE
+        # See https://bugs.archlinux.org/task/65921
+        PrivateUsers = !need_CAP_NET_BIND_SERVICE;
+        ProtectClock = true;
+        ProtectControlGroups = true;
+        ProtectHome = true;
+        ProtectHostname = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectSystem = "strict";
+        RemoveIPC = true;
+        # AF_UNIX is for /run/systemd/notify
+        RestrictAddressFamilies = [ "AF_UNIX" "AF_INET" "AF_INET6" ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+        SystemCallFilter = [
+          "@system-service"
+          # Groups in @system-service which do not contain a syscall
+          # listed by perf stat -e 'syscalls:sys_enter_*' biboumi biboumi.cfg
+          # in tests, and seem likely not necessary for biboumi.
+          # To run such a perf in ExecStart=, you have to:
+          # - AmbientCapabilities="CAP_SYS_ADMIN"
+          # - mount -o remount,mode=755 /sys/kernel/debug/{,tracing}
+          "~@aio" "~@chown" "~@ipc" "~@keyring" "~@resources" "~@setuid" "~@timer"
+        ];
+        SystemCallArchitectures = "native";
+        SystemCallErrorNumber = "EPERM";
+      };
+    };
+  };
+
+  meta.maintainers = with maintainers; [ julm ];
+}
diff --git a/nixos/modules/services/networking/bitcoind.nix b/nixos/modules/services/networking/bitcoind.nix
index 4e00a88654747..bc9aa53f49aa7 100644
--- a/nixos/modules/services/networking/bitcoind.nix
+++ b/nixos/modules/services/networking/bitcoind.nix
@@ -3,31 +3,8 @@
 with lib;
 
 let
-  cfg = config.services.bitcoind;
-  pidFile = "${cfg.dataDir}/bitcoind.pid";
-  configFile = pkgs.writeText "bitcoin.conf" ''
-    ${optionalString cfg.testnet "testnet=1"}
-    ${optionalString (cfg.dbCache != null) "dbcache=${toString cfg.dbCache}"}
-    ${optionalString (cfg.prune != null) "prune=${toString cfg.prune}"}
-
-    # Connection options
-    ${optionalString (cfg.port != null) "port=${toString cfg.port}"}
-
-    # RPC server options
-    ${optionalString (cfg.rpc.port != null) "rpcport=${toString cfg.rpc.port}"}
-    ${concatMapStringsSep  "\n"
-      (rpcUser: "rpcauth=${rpcUser.name}:${rpcUser.passwordHMAC}")
-      (attrValues cfg.rpc.users)
-    }
 
-    # Extra config options (from bitcoind nixos service)
-    ${cfg.extraConfig}
-  '';
-  cmdlineOptions = escapeShellArgs [
-    "-conf=${cfg.configFile}"
-    "-datadir=${cfg.dataDir}"
-    "-pid=${pidFile}"
-  ];
+  eachBitcoind = config.services.bitcoind;
 
   rpcUserOpts = { name, ... }: {
     options = {
@@ -39,11 +16,14 @@ let
         '';
       };
       passwordHMAC = mkOption {
-        type = with types; uniq (strMatching "[0-9a-f]+\\$[0-9a-f]{64}");
+        type = types.uniq (types.strMatching "[0-9a-f]+\\$[0-9a-f]{64}");
         example = "f7efda5c189b999524f151318c0c86$d5b51b3beffbc02b724e5d095828e0bc8b2456e9ac8757ae3211a5d9b16a22ae";
         description = ''
           Password HMAC-SHA-256 for JSON-RPC connections. Must be a string of the
           format &lt;SALT-HEX&gt;$&lt;HMAC-HEX&gt;.
+
+          Tool (Python script) for HMAC generation is available here:
+          <link xlink:href="https://github.com/bitcoin/bitcoin/blob/master/share/rpcauth/rpcauth.py"/>
         '';
       };
     };
@@ -51,10 +31,10 @@ let
       name = mkDefault name;
     };
   };
-in {
-  options = {
 
-    services.bitcoind = {
+  bitcoindOpts = { config, lib, name, ...}: {
+    options = {
+
       enable = mkEnableOption "Bitcoin daemon";
 
       package = mkOption {
@@ -63,12 +43,14 @@ in {
         defaultText = "pkgs.bitcoind";
         description = "The package providing bitcoin binaries.";
       };
+
       configFile = mkOption {
-        type = types.path;
-        default = configFile;
-        example = "/etc/bitcoind.conf";
+        type = types.nullOr types.path;
+        default = null;
+        example = "/var/lib/${name}/bitcoin.conf";
         description = "The configuration file path to supply bitcoind.";
       };
+
       extraConfig = mkOption {
         type = types.lines;
         default = "";
@@ -79,20 +61,22 @@ in {
         '';
         description = "Additional configurations to be appended to <filename>bitcoin.conf</filename>.";
       };
+
       dataDir = mkOption {
         type = types.path;
-        default = "/var/lib/bitcoind";
+        default = "/var/lib/bitcoind-${name}";
         description = "The data directory for bitcoind.";
       };
 
       user = mkOption {
         type = types.str;
-        default = "bitcoin";
+        default = "bitcoind-${name}";
         description = "The user as which to run bitcoind.";
       };
+
       group = mkOption {
         type = types.str;
-        default = cfg.user;
+        default = config.user;
         description = "The group as which to run bitcoind.";
       };
 
@@ -110,29 +94,36 @@ in {
               bob.passwordHMAC = "b2dd077cb54591a2f3139e69a897ac$4e71f08d48b4347cf8eff3815c0e25ae2e9a4340474079f55705f40574f4ec99";
             }
           '';
-          type = with types; loaOf (submodule rpcUserOpts);
-          description = ''
-            RPC user information for JSON-RPC connnections.
-          '';
+          type = types.attrsOf (types.submodule rpcUserOpts);
+          description = "RPC user information for JSON-RPC connnections.";
         };
       };
 
+      pidFile = mkOption {
+        type = types.path;
+        default = "${config.dataDir}/bitcoind.pid";
+        description = "Location of bitcoind pid file.";
+      };
+
       testnet = mkOption {
         type = types.bool;
         default = false;
-        description = "Whether to use the test chain.";
+        description = "Whether to use the testnet instead of mainnet.";
       };
+
       port = mkOption {
         type = types.nullOr types.port;
         default = null;
         description = "Override the default port on which to listen for connections.";
       };
+
       dbCache = mkOption {
         type = types.nullOr (types.ints.between 4 16384);
         default = null;
         example = 4000;
-        description = "Override the default database cache size in megabytes.";
+        description = "Override the default database cache size in MiB.";
       };
+
       prune = mkOption {
         type = types.nullOr (types.coercedTo
           (types.enum [ "disable" "manual" ])
@@ -149,45 +140,122 @@ in {
           and -rescan. Warning: Reverting this setting requires re-downloading
           the entire blockchain. ("disable" = disable pruning blocks, "manual"
           = allow manual pruning via RPC, >=550 = automatically prune block files
-          to stay under the specified target size in MiB)
+          to stay under the specified target size in MiB).
+        '';
+      };
+
+      extraCmdlineOptions = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        description = ''
+          Extra command line options to pass to bitcoind.
+          Run bitcoind --help to list all available options.
         '';
       };
     };
   };
+in
+{
 
-  config = mkIf cfg.enable {
-    environment.systemPackages = [ cfg.package ];
-    systemd.tmpfiles.rules = [
-      "d '${cfg.dataDir}' 0770 '${cfg.user}' '${cfg.group}' - -"
-      "L '${cfg.dataDir}/bitcoin.conf' - - - - '${cfg.configFile}'"
-    ];
-    systemd.services.bitcoind = {
-      description = "Bitcoin daemon";
-      after = [ "network.target" ];
-      wantedBy = [ "multi-user.target" ];
-      serviceConfig = {
-        User = cfg.user;
-        Group = cfg.group;
-        ExecStart = "${cfg.package}/bin/bitcoind ${cmdlineOptions}";
-        Restart = "on-failure";
-
-        # Hardening measures
-        PrivateTmp = "true";
-        ProtectSystem = "full";
-        NoNewPrivileges = "true";
-        PrivateDevices = "true";
-        MemoryDenyWriteExecute = "true";
-      };
+  options = {
+    services.bitcoind = mkOption {
+      type = types.attrsOf (types.submodule bitcoindOpts);
+      default = {};
+      description = "Specification of one or more bitcoind instances.";
     };
-    users.users.${cfg.user} = {
+  };
+
+  config = mkIf (eachBitcoind != {}) {
+
+    assertions = flatten (mapAttrsToList (bitcoindName: cfg: [
+    {
+      assertion = (cfg.prune != null) -> (builtins.elem cfg.prune [ "disable" "manual" 0 1 ] || (builtins.isInt cfg.prune && cfg.prune >= 550));
+      message = ''
+        If set, services.bitcoind.${bitcoindName}.prune has to be "disable", "manual", 0 , 1 or >= 550.
+      '';
+    }
+    {
+      assertion = (cfg.rpc.users != {}) -> (cfg.configFile == null);
+      message = ''
+        You cannot set both services.bitcoind.${bitcoindName}.rpc.users and services.bitcoind.${bitcoindName}.configFile
+        as they are exclusive. RPC user setting would have no effect if custom configFile would be used.
+      '';
+    }
+    ]) eachBitcoind);
+
+    environment.systemPackages = flatten (mapAttrsToList (bitcoindName: cfg: [
+      cfg.package
+    ]) eachBitcoind);
+
+    systemd.services = mapAttrs' (bitcoindName: cfg: (
+      nameValuePair "bitcoind-${bitcoindName}" (
+      let
+        configFile = pkgs.writeText "bitcoin.conf" ''
+          # If Testnet is enabled, we need to add [test] section
+          # otherwise, some options (e.g.: custom RPC port) will not work
+          ${optionalString cfg.testnet "[test]"}
+          # RPC users
+          ${concatMapStringsSep  "\n"
+            (rpcUser: "rpcauth=${rpcUser.name}:${rpcUser.passwordHMAC}")
+            (attrValues cfg.rpc.users)
+          }
+          # Extra config options (from bitcoind nixos service)
+          ${cfg.extraConfig}
+        '';
+      in {
+        description = "Bitcoin daemon";
+        after = [ "network.target" ];
+        wantedBy = [ "multi-user.target" ];
+        serviceConfig = {
+          User = cfg.user;
+          Group = cfg.group;
+          ExecStart = ''
+            ${cfg.package}/bin/bitcoind \
+            ${if (cfg.configFile != null) then
+              "-conf=${cfg.configFile}"
+            else
+              "-conf=${configFile}"
+            } \
+            -datadir=${cfg.dataDir} \
+            -pid=${cfg.pidFile} \
+            ${optionalString cfg.testnet "-testnet"}\
+            ${optionalString (cfg.port != null) "-port=${toString cfg.port}"}\
+            ${optionalString (cfg.prune != null) "-prune=${toString cfg.prune}"}\
+            ${optionalString (cfg.dbCache != null) "-dbcache=${toString cfg.dbCache}"}\
+            ${optionalString (cfg.rpc.port != null) "-rpcport=${toString cfg.rpc.port}"}\
+            ${toString cfg.extraCmdlineOptions}
+          '';
+          Restart = "on-failure";
+
+          # Hardening measures
+          PrivateTmp = "true";
+          ProtectSystem = "full";
+          NoNewPrivileges = "true";
+          PrivateDevices = "true";
+          MemoryDenyWriteExecute = "true";
+        };
+      }
+    ))) eachBitcoind;
+
+    systemd.tmpfiles.rules = flatten (mapAttrsToList (bitcoindName: cfg: [
+      "d '${cfg.dataDir}' 0770 '${cfg.user}' '${cfg.group}' - -"
+    ]) eachBitcoind);
+
+    users.users = mapAttrs' (bitcoindName: cfg: (
+      nameValuePair "bitcoind-${bitcoindName}" {
       name = cfg.user;
       group = cfg.group;
       description = "Bitcoin daemon user";
       home = cfg.dataDir;
       isSystemUser = true;
-    };
-    users.groups.${cfg.group} = {
-      name = cfg.group;
-    };
+    })) eachBitcoind;
+
+    users.groups = mapAttrs' (bitcoindName: cfg: (
+      nameValuePair "${cfg.group}" { }
+    )) eachBitcoind;
+
   };
+
+  meta.maintainers = with maintainers; [ _1000101 ];
+
 }
diff --git a/nixos/modules/services/networking/blockbook-frontend.nix b/nixos/modules/services/networking/blockbook-frontend.nix
new file mode 100644
index 0000000000000..dde24522756af
--- /dev/null
+++ b/nixos/modules/services/networking/blockbook-frontend.nix
@@ -0,0 +1,275 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  eachBlockbook = config.services.blockbook-frontend;
+
+  blockbookOpts = { config, lib, name, ...}: {
+
+    options = {
+
+      enable = mkEnableOption "blockbook-frontend application.";
+
+      package = mkOption {
+        type = types.package;
+        default = pkgs.blockbook;
+        description = "Which blockbook package to use.";
+      };
+
+      user = mkOption {
+        type = types.str;
+        default = "blockbook-frontend-${name}";
+        description = "The user as which to run blockbook-frontend-${name}.";
+      };
+
+      group = mkOption {
+        type = types.str;
+        default = "${config.user}";
+        description = "The group as which to run blockbook-frontend-${name}.";
+      };
+
+      certFile = mkOption {
+        type = types.nullOr types.path;
+        default = null;
+        example = "/etc/secrets/blockbook-frontend-${name}/certFile";
+        description = ''
+          To enable SSL, specify path to the name of certificate files without extension.
+          Expecting <filename>certFile.crt</filename> and <filename>certFile.key</filename>.
+        '';
+      };
+
+      configFile = mkOption {
+        type = with types; nullOr path;
+        default = null;
+        example = "${config.dataDir}/config.json";
+        description = "Location of the blockbook configuration file.";
+      };
+
+      coinName = mkOption {
+        type = types.str;
+        default = "Bitcoin";
+        example = "Bitcoin";
+        description = ''
+          See <link xlink:href="https://github.com/trezor/blockbook/blob/master/bchain/coins/blockchain.go#L61"/>
+          for current of coins supported in master (Note: may differ from release).
+        '';
+      };
+
+      cssDir = mkOption {
+        type = types.path;
+        default = "${config.package}/share/css/";
+        example = "${config.dataDir}/static/css/";
+        description = ''
+          Location of the dir with <filename>main.css</filename> CSS file.
+          By default, the one shipped with the package is used.
+        '';
+      };
+
+      dataDir = mkOption {
+        type = types.path;
+        default = "/var/lib/blockbook-frontend-${name}";
+        description = "Location of blockbook-frontend-${name} data directory.";
+      };
+
+      debug = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Debug mode, return more verbose errors, reload templates on each request.";
+      };
+
+      internal = mkOption {
+        type = types.nullOr types.str;
+        default = ":9030";
+        example = ":9030";
+        description = "Internal http server binding <literal>[address]:port</literal>.";
+      };
+
+      messageQueueBinding = mkOption {
+        type = types.str;
+        default = "tcp://127.0.0.1:38330";
+        example = "tcp://127.0.0.1:38330";
+        description = "Message Queue Binding <literal>address:port</literal>.";
+      };
+
+      public = mkOption {
+        type = types.nullOr types.str;
+        default = ":9130";
+        example = ":9130";
+        description = "Public http server binding <literal>[address]:port</literal>.";
+      };
+
+      rpc = {
+        url = mkOption {
+          type = types.str;
+          default = "http://127.0.0.1";
+          description = "URL for JSON-RPC connections.";
+        };
+
+        port = mkOption {
+          type = types.port;
+          default = 8030;
+          description = "Port for JSON-RPC connections.";
+        };
+
+        user = mkOption {
+          type = types.str;
+          default = "rpc";
+          example = "rpc";
+          description = "Username for JSON-RPC connections.";
+        };
+
+        password = mkOption {
+          type = types.str;
+          default = "rpc";
+          example = "rpc";
+          description = ''
+            RPC password for JSON-RPC connections.
+            Warning: this is stored in cleartext in the Nix store!!!
+            Use <literal>configFile</literal> or <literal>passwordFile</literal> if needed.
+          '';
+        };
+
+        passwordFile = mkOption {
+          type = types.nullOr types.path;
+          default = null;
+          description = ''
+            File containing password of the RPC user.
+            Note: This options is ignored when <literal>configFile</literal> is used.
+          '';
+        };
+      };
+
+      sync = mkOption {
+        type = types.bool;
+        default = true;
+        description = "Synchronizes until tip, if together with zeromq, keeps index synchronized.";
+      };
+
+      templateDir = mkOption {
+        type = types.path;
+        default = "${config.package}/share/templates/";
+        example = "${config.dataDir}/templates/static/";
+        description = "Location of the HTML templates. By default, ones shipped with the package are used.";
+      };
+
+      extraConfig = mkOption {
+        type = types.attrs;
+        default = {};
+        example = literalExample '' {
+          alternative_estimate_fee = "whatthefee-disabled";
+          alternative_estimate_fee_params = "{\"url\": \"https://whatthefee.io/data.json\", \"periodSeconds\": 60}";
+          fiat_rates = "coingecko";
+          fiat_rates_params = "{\"url\": \"https://api.coingecko.com/api/v3\", \"coin\": \"bitcoin\", \"periodSeconds\": 60}";
+          coin_shortcut = "BTC";
+          coin_label = "Bitcoin";
+          xpub_magic = 76067358;
+          xpub_magic_segwit_p2sh = 77429938;
+          xpub_magic_segwit_native = 78792518;
+        }'';
+        description = ''
+          Additional configurations to be appended to <filename>coin.conf</filename>.
+          Overrides any already defined configuration options.
+          See <link xlink:href="https://github.com/trezor/blockbook/tree/master/configs/coins"/>
+          for current configuration options supported in master (Note: may differ from release).
+        '';
+      };
+
+      extraCmdLineOptions = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        example = [ "-workers=1" "-dbcache=0" "-logtosderr" ];
+        description = ''
+          Extra command line options to pass to Blockbook.
+          Run blockbook --help to list all available options.
+        '';
+      };
+    };
+  };
+in
+{
+  # interface
+
+  options = {
+    services.blockbook-frontend = mkOption {
+      type = types.attrsOf (types.submodule blockbookOpts);
+      default = {};
+      description = "Specification of one or more blockbook-frontend instances.";
+    };
+  };
+
+  # implementation
+
+  config = mkIf (eachBlockbook != {}) {
+
+    systemd.services = mapAttrs' (blockbookName: cfg: (
+      nameValuePair "blockbook-frontend-${blockbookName}" (
+        let
+          configFile = if cfg.configFile != null then cfg.configFile else
+            pkgs.writeText "config.conf" (builtins.toJSON ( {
+                coin_name = "${cfg.coinName}";
+                rpc_user = "${cfg.rpc.user}";
+                rpc_pass = "${cfg.rpc.password}";
+                rpc_url = "${cfg.rpc.url}:${toString cfg.rpc.port}";
+                message_queue_binding = "${cfg.messageQueueBinding}";
+              } // cfg.extraConfig)
+            );
+        in {
+          description = "blockbook-frontend-${blockbookName} daemon";
+          after = [ "network.target" ];
+          wantedBy = [ "multi-user.target" ];
+          preStart = ''
+            ln -sf ${cfg.templateDir} ${cfg.dataDir}/static/
+            ln -sf ${cfg.cssDir} ${cfg.dataDir}/static/
+            ${optionalString (cfg.rpc.passwordFile != null && cfg.configFile == null) ''
+              CONFIGTMP=$(mktemp)
+              ${pkgs.jq}/bin/jq ".rpc_pass = \"$(cat ${cfg.rpc.passwordFile})\"" ${configFile} > $CONFIGTMP
+              mv $CONFIGTMP ${cfg.dataDir}/${blockbookName}-config.json
+            ''}
+          '';
+          serviceConfig = {
+            User = cfg.user;
+            Group = cfg.group;
+            ExecStart = ''
+               ${cfg.package}/bin/blockbook \
+               ${if (cfg.rpc.passwordFile != null && cfg.configFile == null) then
+               "-blockchaincfg=${cfg.dataDir}/${blockbookName}-config.json"
+               else
+               "-blockchaincfg=${configFile}"
+               } \
+               -datadir=${cfg.dataDir} \
+               ${optionalString (cfg.sync != false) "-sync"} \
+               ${optionalString (cfg.certFile != null) "-certfile=${toString cfg.certFile}"} \
+               ${optionalString (cfg.debug != false) "-debug"} \
+               ${optionalString (cfg.internal != null) "-internal=${toString cfg.internal}"} \
+               ${optionalString (cfg.public != null) "-public=${toString cfg.public}"} \
+               ${toString cfg.extraCmdLineOptions}
+            '';
+            Restart = "on-failure";
+            WorkingDirectory = cfg.dataDir;
+            LimitNOFILE = 65536;
+          };
+        }
+    ) )) eachBlockbook;
+
+    systemd.tmpfiles.rules = flatten (mapAttrsToList (blockbookName: cfg: [
+      "d ${cfg.dataDir} 0750 ${cfg.user} ${cfg.group} - -"
+      "d ${cfg.dataDir}/static 0750 ${cfg.user} ${cfg.group} - -"
+    ]) eachBlockbook);
+
+    users.users = mapAttrs' (blockbookName: cfg: (
+      nameValuePair "blockbook-frontend-${blockbookName}" {
+      name = cfg.user;
+      group = cfg.group;
+      home = cfg.dataDir;
+      isSystemUser = true;
+    })) eachBlockbook;
+
+    users.groups = mapAttrs' (instanceName: cfg: (
+      nameValuePair "${cfg.group}" { })) eachBlockbook;
+  };
+
+  meta.maintainers = with maintainers; [ _1000101 ];
+
+}
diff --git a/nixos/modules/services/networking/corerad.nix b/nixos/modules/services/networking/corerad.nix
index 5d73c0a0d7790..d90a5923bc62e 100644
--- a/nixos/modules/services/networking/corerad.nix
+++ b/nixos/modules/services/networking/corerad.nix
@@ -77,8 +77,11 @@ in {
         AmbientCapabilities = "CAP_NET_ADMIN CAP_NET_RAW";
         NoNewPrivileges = true;
         DynamicUser = true;
+        Type = "notify";
+        NotifyAccess = "main";
         ExecStart = "${getBin cfg.package}/bin/corerad -c=${cfg.configFile}";
         Restart = "on-failure";
+        RestartKillSignal = "SIGHUP";
       };
     };
   };
diff --git a/nixos/modules/services/networking/dhcpd.nix b/nixos/modules/services/networking/dhcpd.nix
index 67f7d81188700..8966deac76cba 100644
--- a/nixos/modules/services/networking/dhcpd.nix
+++ b/nixos/modules/services/networking/dhcpd.nix
@@ -11,7 +11,7 @@ let
     ''
       default-lease-time 600;
       max-lease-time 7200;
-      authoritative;
+      ${optionalString (!cfg.authoritative) "not "}authoritative;
       ddns-update-style interim;
       log-facility local1; # see dhcpd.nix
 
@@ -176,6 +176,16 @@ let
       '';
     };
 
+    authoritative = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        Whether the DHCP server shall send DHCPNAK messages to misconfigured
+        clients. If this is not done, clients may be unable to get a correct
+        IP address after changing subnets until their old lease has expired.
+      '';
+    };
+
   };
 
 in
diff --git a/nixos/modules/services/networking/gateone.nix b/nixos/modules/services/networking/gateone.nix
index 4456a95402edd..56f2ba21a125b 100644
--- a/nixos/modules/services/networking/gateone.nix
+++ b/nixos/modules/services/networking/gateone.nix
@@ -56,4 +56,4 @@ config = mkIf cfg.enable {
   };
 };
 }
-  
+
diff --git a/nixos/modules/services/networking/heyefi.nix b/nixos/modules/services/networking/heyefi.nix
deleted file mode 100644
index fc2b5a8485780..0000000000000
--- a/nixos/modules/services/networking/heyefi.nix
+++ /dev/null
@@ -1,82 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-with lib;
-
-let
-
-  cfg = config.services.heyefi;
-in
-
-{
-
-  ###### interface
-
-  options = {
-
-    services.heyefi = {
-
-      enable = mkEnableOption "heyefi";
-
-      cardMacaddress = mkOption {
-        default = "";
-        description = ''
-          An Eye-Fi card MAC address.
-          '';
-      };
-
-      uploadKey = mkOption {
-        default = "";
-        description = ''
-          An Eye-Fi card's upload key.
-          '';
-      };
-
-      uploadDir = mkOption {
-        example = "/home/username/pictures";
-        description = ''
-          The directory to upload the files to.
-          '';
-      };
-
-      user = mkOption {
-        default = "root";
-        description = ''
-          heyefi will be run under this user (user must exist,
-          this can be your user name).
-        '';
-      };
-
-    };
-
-  };
-
-
-  ###### implementation
-
-  config = mkIf cfg.enable {
-
-    systemd.services.heyefi =
-      {
-        description = "heyefi service";
-        after = [ "network.target" ];
-        wantedBy = [ "multi-user.target" ];
-        serviceConfig = {
-          User = "${cfg.user}";
-          Restart = "always";
-          ExecStart = "${pkgs.heyefi}/bin/heyefi";
-        };
-
-      };
-
-    environment.etc."heyefi/heyefi.config".text =
-      ''
-        # /etc/heyefi/heyefi.conf: DO NOT EDIT -- this file has been generated automatically.
-        cards = [["${config.services.heyefi.cardMacaddress}","${config.services.heyefi.uploadKey}"]]
-        upload_dir = "${toString config.services.heyefi.uploadDir}"
-      '';
-
-    environment.systemPackages = [ pkgs.heyefi ];
-
-  };
-
-}
diff --git a/nixos/modules/services/networking/hylafax/options.nix b/nixos/modules/services/networking/hylafax/options.nix
index 4ac6d3fa8432d..9e28d09dffca5 100644
--- a/nixos/modules/services/networking/hylafax/options.nix
+++ b/nixos/modules/services/networking/hylafax/options.nix
@@ -3,7 +3,7 @@
 let
 
   inherit (lib.options) literalExample mkEnableOption mkOption;
-  inherit (lib.types) bool enum int lines loaOf nullOr path str submodule;
+  inherit (lib.types) bool enum int lines attrsOf nullOr path str submodule;
   inherit (lib.modules) mkDefault mkIf mkMerge;
 
   commonDescr = ''
@@ -248,7 +248,7 @@ in
     };
 
     modems = mkOption {
-      type = loaOf (submodule [ modemConfigOptions ]);
+      type = attrsOf (submodule [ modemConfigOptions ]);
       default = {};
       example.ttyS1 = {
         type = "cirrus";
diff --git a/nixos/modules/services/networking/jicofo.nix b/nixos/modules/services/networking/jicofo.nix
new file mode 100644
index 0000000000000..160a5fea91a0e
--- /dev/null
+++ b/nixos/modules/services/networking/jicofo.nix
@@ -0,0 +1,152 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.jicofo;
+in
+{
+  options.services.jicofo = with types; {
+    enable = mkEnableOption "Jitsi Conference Focus - component of Jitsi Meet";
+
+    xmppHost = mkOption {
+      type = str;
+      example = "localhost";
+      description = ''
+        Hostname of the XMPP server to connect to.
+      '';
+    };
+
+    xmppDomain = mkOption {
+      type = nullOr str;
+      example = "meet.example.org";
+      description = ''
+        Domain name of the XMMP server to which to connect as a component.
+
+        If null, <option>xmppHost</option> is used.
+      '';
+    };
+
+    componentPasswordFile = mkOption {
+      type = str;
+      example = "/run/keys/jicofo-component";
+      description = ''
+        Path to file containing component secret.
+      '';
+    };
+
+    userName = mkOption {
+      type = str;
+      default = "focus";
+      description = ''
+        User part of the JID for XMPP user connection.
+      '';
+    };
+
+    userDomain = mkOption {
+      type = str;
+      example = "auth.meet.example.org";
+      description = ''
+        Domain part of the JID for XMPP user connection.
+      '';
+    };
+
+    userPasswordFile = mkOption {
+      type = str;
+      example = "/run/keys/jicofo-user";
+      description = ''
+        Path to file containing password for XMPP user connection.
+      '';
+    };
+
+    bridgeMuc = mkOption {
+      type = str;
+      example = "jvbbrewery@internal.meet.example.org";
+      description = ''
+        JID of the internal MUC used to communicate with Videobridges.
+      '';
+    };
+
+    config = mkOption {
+      type = attrsOf str;
+      default = { };
+      example = literalExample ''
+        {
+          "org.jitsi.jicofo.auth.URL" = "XMPP:jitsi-meet.example.com";
+        }
+      '';
+      description = ''
+        Contents of the <filename>sip-communicator.properties</filename> configuration file for jicofo.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    services.jicofo.config = mapAttrs (_: v: mkDefault v) {
+      "org.jitsi.jicofo.BRIDGE_MUC" = cfg.bridgeMuc;
+    };
+
+    users.groups.jitsi-meet = {};
+
+    systemd.services.jicofo = let
+      jicofoProps = {
+        "-Dnet.java.sip.communicator.SC_HOME_DIR_LOCATION" = "/etc/jitsi";
+        "-Dnet.java.sip.communicator.SC_HOME_DIR_NAME" = "jicofo";
+        "-Djava.util.logging.config.file" = "/etc/jitsi/jicofo/logging.properties";
+      };
+    in
+    {
+      description = "JItsi COnference FOcus";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+
+      restartTriggers = [
+        config.environment.etc."jitsi/jicofo/sip-communicator.properties".source
+      ];
+      environment.JAVA_SYS_PROPS = concatStringsSep " " (mapAttrsToList (k: v: "${k}=${toString v}") jicofoProps);
+
+      script = ''
+        ${pkgs.jicofo}/bin/jicofo \
+          --host=${cfg.xmppHost} \
+          --domain=${if cfg.xmppDomain == null then cfg.xmppHost else cfg.xmppDomain} \
+          --secret=$(cat ${cfg.componentPasswordFile}) \
+          --user_name=${cfg.userName} \
+          --user_domain=${cfg.userDomain} \
+          --user_password=$(cat ${cfg.userPasswordFile})
+      '';
+
+      serviceConfig = {
+        Type = "exec";
+
+        DynamicUser = true;
+        User = "jicofo";
+        Group = "jitsi-meet";
+
+        CapabilityBoundingSet = "";
+        NoNewPrivileges = true;
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        PrivateTmp = true;
+        PrivateDevices = true;
+        ProtectHostname = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectControlGroups = true;
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" "AF_UNIX" ];
+        RestrictNamespaces = true;
+        LockPersonality = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+      };
+    };
+
+    environment.etc."jitsi/jicofo/sip-communicator.properties".source =
+      pkgs.writeText "sip-communicator.properties" (
+        generators.toKeyValue {} cfg.config
+      );
+    environment.etc."jitsi/jicofo/logging.properties".source =
+      mkDefault "${pkgs.jicofo}/etc/jitsi/jicofo/logging.properties-journal";
+  };
+
+  meta.maintainers = lib.teams.jitsi.members;
+}
diff --git a/nixos/modules/services/networking/jitsi-videobridge.nix b/nixos/modules/services/networking/jitsi-videobridge.nix
new file mode 100644
index 0000000000000..5482e997a4018
--- /dev/null
+++ b/nixos/modules/services/networking/jitsi-videobridge.nix
@@ -0,0 +1,276 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.jitsi-videobridge;
+  attrsToArgs = a: concatStringsSep " " (mapAttrsToList (k: v: "${k}=${toString v}") a);
+
+  # HOCON is a JSON superset that videobridge2 uses for configuration.
+  # It can substitute environment variables which we use for passwords here.
+  # https://github.com/lightbend/config/blob/master/README.md
+  #
+  # Substitution for environment variable FOO is represented as attribute set
+  # { __hocon_envvar = "FOO"; }
+  toHOCON = x: if isAttrs x && x ? __hocon_envvar then ("\${" + x.__hocon_envvar + "}")
+    else if isAttrs x then "{${ concatStringsSep "," (mapAttrsToList (k: v: ''"${k}":${toHOCON v}'') x) }}"
+    else if isList x then "[${ concatMapStringsSep "," toHOCON x }]"
+    else builtins.toJSON x;
+
+  # We're passing passwords in environment variables that have names generated
+  # from an attribute name, which may not be a valid bash identifier.
+  toVarName = s: "XMPP_PASSWORD_" + stringAsChars (c: if builtins.match "[A-Za-z0-9]" c != null then c else "_") s;
+
+  defaultJvbConfig = {
+    videobridge = {
+      ice = {
+        tcp = {
+          enabled = true;
+          port = 4443;
+        };
+        udp.port = 10000;
+      };
+      stats = {
+        enabled = true;
+        transports = [ { type = "muc"; } ];
+      };
+      apis.xmpp-client.configs = flip mapAttrs cfg.xmppConfigs (name: xmppConfig: {
+        hostname = xmppConfig.hostName;
+        domain = xmppConfig.domain;
+        username = xmppConfig.userName;
+        password = { __hocon_envvar = toVarName name; };
+        muc_jids = xmppConfig.mucJids;
+        muc_nickname = xmppConfig.mucNickname;
+        disable_certificate_verification = xmppConfig.disableCertificateVerification;
+      });
+    };
+  };
+
+  # Allow overriding leaves of the default config despite types.attrs not doing any merging.
+  jvbConfig = recursiveUpdate defaultJvbConfig cfg.config;
+in
+{
+  options.services.jitsi-videobridge = with types; {
+    enable = mkEnableOption "Jitsi Videobridge, a WebRTC compatible video router";
+
+    config = mkOption {
+      type = attrs;
+      default = { };
+      example = literalExample ''
+        {
+          videobridge = {
+            ice.udp.port = 5000;
+            websockets = {
+              enabled = true;
+              server-id = "jvb1";
+            };
+          };
+        }
+      '';
+      description = ''
+        Videobridge configuration.
+
+        See <link xlink:href="https://github.com/jitsi/jitsi-videobridge/blob/master/src/main/resources/reference.conf" />
+        for default configuration with comments.
+      '';
+    };
+
+    xmppConfigs = mkOption {
+      description = ''
+        XMPP servers to connect to.
+
+        See <link xlink:href="https://github.com/jitsi/jitsi-videobridge/blob/master/doc/muc.md" /> for more information.
+      '';
+      default = { };
+      example = literalExample ''
+        {
+          "localhost" = {
+            hostName = "localhost";
+            userName = "jvb";
+            domain = "auth.xmpp.example.org";
+            passwordFile = "/var/lib/jitsi-meet/videobridge-secret";
+            mucJids = "jvbbrewery@internal.xmpp.example.org";
+          };
+        }
+      '';
+      type = attrsOf (submodule ({ name, ... }: {
+        options = {
+          hostName = mkOption {
+            type = str;
+            example = "xmpp.example.org";
+            description = ''
+              Hostname of the XMPP server to connect to. Name of the attribute set is used by default.
+            '';
+          };
+          domain = mkOption {
+            type = nullOr str;
+            default = null;
+            example = "auth.xmpp.example.org";
+            description = ''
+              Domain part of JID of the XMPP user, if it is different from hostName.
+            '';
+          };
+          userName = mkOption {
+            type = str;
+            default = "jvb";
+            description = ''
+              User part of the JID.
+            '';
+          };
+          passwordFile = mkOption {
+            type = str;
+            example = "/run/keys/jitsi-videobridge-xmpp1";
+            description = ''
+              File containing the password for the user.
+            '';
+          };
+          mucJids = mkOption {
+            type = str;
+            example = "jvbbrewery@internal.xmpp.example.org";
+            description = ''
+              JID of the MUC to join. JiCoFo needs to be configured to join the same MUC.
+            '';
+          };
+          mucNickname = mkOption {
+            # Upstream DEBs use UUID, let's use hostname instead.
+            type = str;
+            description = ''
+              Videobridges use the same XMPP account and need to be distinguished by the
+              nickname (aka resource part of the JID). By default, system hostname is used.
+            '';
+          };
+          disableCertificateVerification = mkOption {
+            type = bool;
+            default = false;
+            description = ''
+              Whether to skip validation of the server's certificate.
+            '';
+          };
+        };
+        config = {
+          hostName = mkDefault name;
+          mucNickname = mkDefault (builtins.replaceStrings [ "." ] [ "-" ] (
+            config.networking.hostName + optionalString (config.networking.domain != null) ".${config.networking.domain}"
+          ));
+        };
+      }));
+    };
+
+    nat = {
+      localAddress = mkOption {
+        type = nullOr str;
+        default = null;
+        example = "192.168.1.42";
+        description = ''
+          Local address when running behind NAT.
+        '';
+      };
+
+      publicAddress = mkOption {
+        type = nullOr str;
+        default = null;
+        example = "1.2.3.4";
+        description = ''
+          Public address when running behind NAT.
+        '';
+      };
+    };
+
+    extraProperties = mkOption {
+      type = attrsOf str;
+      default = { };
+      description = ''
+        Additional Java properties passed to jitsi-videobridge.
+      '';
+    };
+
+    openFirewall = mkOption {
+      type = bool;
+      default = false;
+      description = ''
+        Whether to open ports in the firewall for the videobridge.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    users.groups.jitsi-meet = {};
+
+    services.jitsi-videobridge.extraProperties = optionalAttrs (cfg.nat.localAddress != null) {
+      "org.ice4j.ice.harvest.NAT_HARVESTER_LOCAL_ADDRESS" = cfg.nat.localAddress;
+      "org.ice4j.ice.harvest.NAT_HARVESTER_PUBLIC_ADDRESS" = cfg.nat.publicAddress;
+    };
+
+    systemd.services.jitsi-videobridge2 = let
+      jvbProps = {
+        "-Dnet.java.sip.communicator.SC_HOME_DIR_LOCATION" = "/etc/jitsi";
+        "-Dnet.java.sip.communicator.SC_HOME_DIR_NAME" = "videobridge";
+        "-Djava.util.logging.config.file" = "/etc/jitsi/videobridge/logging.properties";
+        "-Dconfig.file" = pkgs.writeText "jvb.conf" (toHOCON jvbConfig);
+      } // (mapAttrs' (k: v: nameValuePair "-D${k}" v) cfg.extraProperties);
+    in
+    {
+      aliases = [ "jitsi-videobridge.service" ];
+      description = "Jitsi Videobridge";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+
+      environment.JAVA_SYS_PROPS = attrsToArgs jvbProps;
+
+      script = (concatStrings (mapAttrsToList (name: xmppConfig:
+        "export ${toVarName name}=$(cat ${xmppConfig.passwordFile})\n"
+      ) cfg.xmppConfigs))
+      + ''
+        ${pkgs.jitsi-videobridge}/bin/jitsi-videobridge --apis=none
+      '';
+
+      serviceConfig = {
+        Type = "exec";
+
+        DynamicUser = true;
+        User = "jitsi-videobridge";
+        Group = "jitsi-meet";
+
+        CapabilityBoundingSet = "";
+        NoNewPrivileges = true;
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        PrivateTmp = true;
+        PrivateDevices = true;
+        ProtectHostname = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectControlGroups = true;
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" "AF_UNIX" ];
+        RestrictNamespaces = true;
+        LockPersonality = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+
+        TasksMax = 65000;
+        LimitNPROC = 65000;
+        LimitNOFILE = 65000;
+      };
+    };
+
+    environment.etc."jitsi/videobridge/logging.properties".source =
+      mkDefault "${pkgs.jitsi-videobridge}/etc/jitsi/videobridge/logging.properties-journal";
+
+    # (from videobridge2 .deb)
+    # this sets the max, so that we can bump the JVB UDP single port buffer size.
+    boot.kernel.sysctl."net.core.rmem_max" = mkDefault 10485760;
+    boot.kernel.sysctl."net.core.netdev_max_backlog" = mkDefault 100000;
+
+    networking.firewall.allowedTCPPorts = mkIf cfg.openFirewall
+      [ jvbConfig.videobridge.ice.tcp.port ];
+    networking.firewall.allowedUDPPorts = mkIf cfg.openFirewall
+      [ jvbConfig.videobridge.ice.udp.port ];
+
+    assertions = [{
+      message = "publicAddress must be set if and only if localAddress is set";
+      assertion = (cfg.nat.publicAddress == null) == (cfg.nat.localAddress == null);
+    }];
+  };
+
+  meta.maintainers = lib.teams.jitsi.members;
+}
diff --git a/nixos/modules/services/networking/kresd.nix b/nixos/modules/services/networking/kresd.nix
index c5a84eebd46f4..ccb34163d5f36 100644
--- a/nixos/modules/services/networking/kresd.nix
+++ b/nixos/modules/services/networking/kresd.nix
@@ -129,14 +129,17 @@ in {
     systemd.services."kresd@".serviceConfig = {
       ExecStart = "${package}/bin/kresd --noninteractive "
         + "-c ${package}/lib/knot-resolver/distro-preconfig.lua -c ${configFile}";
-      # Ensure correct ownership in case UID or GID changes.
+      # Ensure /run/knot-resolver exists
+      RuntimeDirectory = "knot-resolver";
+      RuntimeDirectoryMode = "0770";
+      # Ensure /var/lib/knot-resolver exists
+      StateDirectory = "knot-resolver";
+      StateDirectoryMode = "0770";
+      # Ensure /var/cache/knot-resolver exists
       CacheDirectory = "knot-resolver";
-      CacheDirectoryMode = "0750";
+      CacheDirectoryMode = "0770";
     };
 
-    environment.etc."tmpfiles.d/knot-resolver.conf".source =
-      "${package}/lib/tmpfiles.d/knot-resolver.conf";
-
     # Try cleaning up the previously default location of cache file.
     # Note that /var/cache/* should always be safe to remove.
     # TODO: remove later, probably between 20.09 and 21.03
diff --git a/nixos/modules/services/networking/monero.nix b/nixos/modules/services/networking/monero.nix
index 97af29978397b..fde3293fc131f 100644
--- a/nixos/modules/services/networking/monero.nix
+++ b/nixos/modules/services/networking/monero.nix
@@ -87,7 +87,7 @@ in
       };
 
       rpc.password = mkOption {
-        type = types.str;
+        type = types.nullOr types.str;
         default = null;
         description = ''
           Password for RPC connections.
diff --git a/nixos/modules/services/networking/mstpd.nix b/nixos/modules/services/networking/mstpd.nix
index 5d1fc4a65427d..bd71010ce549c 100644
--- a/nixos/modules/services/networking/mstpd.nix
+++ b/nixos/modules/services/networking/mstpd.nix
@@ -5,7 +5,7 @@ in
 with lib;
 {
   options.services.mstpd = {
-    
+
     enable = mkOption {
       default = false;
       type = types.bool;
diff --git a/nixos/modules/services/networking/namecoind.nix b/nixos/modules/services/networking/namecoind.nix
index 6ca99e1321bdb..16f85df2e77c8 100644
--- a/nixos/modules/services/networking/namecoind.nix
+++ b/nixos/modules/services/networking/namecoind.nix
@@ -89,7 +89,7 @@ in
       };
 
       rpc.password = mkOption {
-        type = types.str;
+        type = types.nullOr types.str;
         default = null;
         description = ''
           Password for RPC connections.
diff --git a/nixos/modules/services/networking/ncdns.nix b/nixos/modules/services/networking/ncdns.nix
new file mode 100644
index 0000000000000..c1832ad175205
--- /dev/null
+++ b/nixos/modules/services/networking/ncdns.nix
@@ -0,0 +1,278 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfgs = config.services;
+  cfg  = cfgs.ncdns;
+
+  dataDir  = "/var/lib/ncdns";
+  username = "ncdns";
+
+  valueType = with types; oneOf [ int str bool path ]
+    // { description = "setting type (integer, string, bool or path)"; };
+
+  configType = with types; attrsOf (nullOr (either valueType configType))
+    // { description = ''
+          ncdns.conf configuration type. The format consists of an
+          attribute set of settings. Each setting can be either `null`,
+          a value or an attribute set. The allowed values are integers,
+          strings, booleans or paths.
+         '';
+       };
+
+  configFile = pkgs.runCommand "ncdns.conf"
+    { json = builtins.toJSON cfg.settings;
+      passAsFile = [ "json" ];
+    }
+    "${pkgs.remarshal}/bin/json2toml < $jsonPath > $out";
+
+  defaultFiles = {
+    public  = "${dataDir}/bit.key";
+    private = "${dataDir}/bit.private";
+    zonePublic  = "${dataDir}/bit-zone.key";
+    zonePrivate = "${dataDir}/bit-zone.private";
+  };
+
+  # if all keys are the default value
+  needsKeygen = all id (flip mapAttrsToList cfg.dnssec.keys
+    (n: v: v == getAttr n defaultFiles));
+
+  mkDefaultAttrs = mapAttrs (n: v: mkDefault v);
+
+in
+
+{
+
+  ###### interface
+
+  options = {
+
+    services.ncdns = {
+
+      enable = mkEnableOption ''
+        ncdns, a Go daemon to bridge Namecoin to DNS.
+        To resolve .bit domains set <literal>services.namecoind.enable = true;</literal>
+        and an RPC username/password
+      '';
+
+      address = mkOption {
+        type = types.str;
+        default = "127.0.0.1";
+        description = ''
+          The IP address the ncdns resolver will bind to.  Leave this unchanged
+          if you do not wish to directly expose the resolver.
+        '';
+      };
+
+      port = mkOption {
+        type = types.port;
+        default = 5333;
+        description = ''
+          The port the ncdns resolver will bind to.
+        '';
+      };
+
+      identity.hostname = mkOption {
+        type = types.str;
+        default = config.networking.hostName;
+        example = "example.com";
+        description = ''
+          The hostname of this ncdns instance, which defaults to the machine
+          hostname. If specified, ncdns lists the hostname as an NS record at
+          the zone apex:
+          <programlisting>
+          bit. IN NS ns1.example.com.
+          </programlisting>
+          If unset ncdns will generate an internal psuedo-hostname under the
+          zone, which will resolve to the value of
+          <option>services.ncdns.identity.address</option>.
+          If you are only using ncdns locally you can ignore this.
+        '';
+      };
+
+      identity.hostmaster = mkOption {
+        type = types.str;
+        default = "";
+        example = "root@example.com";
+        description = ''
+          An email address for the SOA record at the bit zone.
+          If you are only using ncdns locally you can ignore this.
+        '';
+      };
+
+      identity.address = mkOption {
+        type = types.str;
+        default = "127.127.127.127";
+        description = ''
+          The IP address the hostname specified in
+          <option>services.ncdns.identity.hostname</option> should resolve to.
+          If you are only using ncdns locally you can ignore this.
+        '';
+      };
+
+      dnssec.enable = mkEnableOption ''
+        DNSSEC support in ncdns. This will generate KSK and ZSK keypairs
+        (unless provided via the options
+        <option>services.ncdns.dnssec.publicKey</option>,
+        <option>services.ncdns.dnssec.privateKey</option> etc.) and add a trust
+        anchor to recursive resolvers
+      '';
+
+      dnssec.keys.public = mkOption {
+        type = types.path;
+        default = defaultFiles.public;
+        description = ''
+          Path to the file containing the KSK public key.
+          The key can be generated using the <literal>dnssec-keygen</literal>
+          command, provided by the package <package>bind</package> as follows:
+          <programlisting>
+          $ dnssec-keygen -a RSASHA256 -3 -b 2048 -f KSK bit
+          </programlisting>
+        '';
+      };
+
+      dnssec.keys.private = mkOption {
+        type = types.path;
+        default = defaultFiles.private;
+        description = ''
+          Path to the file containing the KSK private key.
+        '';
+      };
+
+      dnssec.keys.zonePublic = mkOption {
+        type = types.path;
+        default = defaultFiles.zonePublic;
+        description = ''
+          Path to the file containing the ZSK public key.
+          The key can be generated using the <literal>dnssec-keygen</literal>
+          command, provided by the package <package>bind</package> as follows:
+          <programlisting>
+          $ dnssec-keygen -a RSASHA256 -3 -b 2048 bit
+          </programlisting>
+        '';
+      };
+
+      dnssec.keys.zonePrivate = mkOption {
+        type = types.path;
+        default = defaultFiles.zonePrivate;
+        description = ''
+          Path to the file containing the ZSK private key.
+        '';
+      };
+
+      settings = mkOption {
+        type = configType;
+        default = { };
+        example = literalExample ''
+          { # enable webserver
+            ncdns.httplistenaddr = ":8202";
+
+            # synchronize TLS certs
+            certstore.nss = true;
+            # note: all paths are relative to the config file
+            certstore.nsscertdir =  "../../var/lib/ncdns";
+            certstore.nssdbdir = "../../home/alice/.pki/nssdb";
+          }
+        '';
+        description = ''
+          ncdns settings. Use this option to configure ncds
+          settings not exposed in a NixOS option or to bypass one.
+          See the example ncdns.conf file at <link xlink:href="
+          https://git.io/JfX7g"/> for the available options.
+        '';
+      };
+
+    };
+
+    services.pdns-recursor.resolveNamecoin = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Resolve <literal>.bit</literal> top-level domains using ncdns and namecoin.
+      '';
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+
+    services.pdns-recursor = mkIf cfgs.pdns-recursor.resolveNamecoin {
+      forwardZonesRecurse.bit = "127.0.0.1:${toString cfg.port}";
+      luaConfig =
+        if cfg.dnssec.enable
+          then ''readTrustAnchorsFromFile("${cfg.dnssec.keys.public}")''
+          else ''addNTA("bit", "namecoin DNSSEC disabled")'';
+    };
+
+    # Avoid pdns-recursor not finding the DNSSEC keys
+    systemd.services.pdns-recursor = mkIf cfgs.pdns-recursor.resolveNamecoin {
+      after = [ "ncdns.service" ];
+      wants = [ "ncdns.service" ];
+    };
+
+    services.ncdns.settings = mkDefaultAttrs {
+      ncdns =
+        { # Namecoin RPC
+          namecoinrpcaddress =
+            "${cfgs.namecoind.rpc.address}:${toString cfgs.namecoind.rpc.port}";
+          namecoinrpcusername = cfgs.namecoind.rpc.user;
+          namecoinrpcpassword = cfgs.namecoind.rpc.password;
+
+          # Identity
+          selfname = cfg.identity.hostname;
+          hostmaster = cfg.identity.hostmaster;
+          selfip = cfg.identity.address;
+
+          # Other
+          bind = "${cfg.address}:${toString cfg.port}";
+        }
+        // optionalAttrs cfg.dnssec.enable
+        { # DNSSEC
+          publickey  = "../.." + cfg.dnssec.keys.public;
+          privatekey = "../.." + cfg.dnssec.keys.private;
+          zonepublickey  = "../.." + cfg.dnssec.keys.zonePublic;
+          zoneprivatekey = "../.." + cfg.dnssec.keys.zonePrivate;
+        };
+
+        # Daemon
+        service.daemon = true;
+        xlog.journal = true;
+    };
+
+    users.users.ncdns =
+      { description = "ncdns daemon user"; };
+
+    systemd.services.ncdns = {
+      description = "ncdns daemon";
+      after    = [ "namecoind.service" ];
+      wantedBy = [ "multi-user.target" ];
+
+      serviceConfig = {
+        User = "ncdns";
+        StateDirectory = "ncdns";
+        Restart = "on-failure";
+        ExecStart = "${pkgs.ncdns}/bin/ncdns -conf=${configFile}";
+      };
+
+      preStart = optionalString (cfg.dnssec.enable && needsKeygen) ''
+        cd ${dataDir}
+        if [ ! -e bit.key ]; then
+          ${pkgs.bind}/bin/dnssec-keygen -a RSASHA256 -3 -b 2048 bit
+          mv Kbit.*.key bit-zone.key
+          mv Kbit.*.private bit-zone.private
+          ${pkgs.bind}/bin/dnssec-keygen -a RSASHA256 -3 -b 2048 -f KSK bit
+          mv Kbit.*.key bit.key
+          mv Kbit.*.private bit.private
+        fi
+      '';
+    };
+
+  };
+
+  meta.maintainers = with lib.maintainers; [ rnhmjoj ];
+
+}
diff --git a/nixos/modules/services/networking/networkmanager.nix b/nixos/modules/services/networking/networkmanager.nix
index cc789897b29fe..17c549d42c329 100644
--- a/nixos/modules/services/networking/networkmanager.nix
+++ b/nixos/modules/services/networking/networkmanager.nix
@@ -458,7 +458,7 @@ in {
 
     systemd.services.NetworkManager-dispatcher = {
       wantedBy = [ "network.target" ];
-      restartTriggers = [ configFile ];
+      restartTriggers = [ configFile overrideNameserversScript ];
 
       # useful binaries for user-specified hooks
       path = [ pkgs.iproute pkgs.utillinux pkgs.coreutils ];
diff --git a/nixos/modules/services/networking/nextdns.nix b/nixos/modules/services/networking/nextdns.nix
new file mode 100644
index 0000000000000..a633bff62ec7e
--- /dev/null
+++ b/nixos/modules/services/networking/nextdns.nix
@@ -0,0 +1,44 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.nextdns;
+in {
+  options = {
+    services.nextdns = {
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Whether to enable the NextDNS DNS/53 to DoH Proxy service.";
+      };
+      arguments = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        example = [ "-config" "10.0.3.0/24=abcdef" ];
+        description = "Additional arguments to be passed to nextdns run.";
+      };
+    };
+  };
+
+  # https://github.com/nextdns/nextdns/blob/628ea509eaaccd27adb66337db03e5b56f6f38a8/host/service/systemd/service.go
+  config = mkIf cfg.enable {
+    systemd.services.nextdns = {
+      description = "NextDNS DNS/53 to DoH Proxy";
+      environment = {
+        SERVICE_RUN_MODE = "1";
+      };
+      serviceConfig = {
+        StartLimitInterval = 5;
+        StartLimitBurst = 10;
+        ExecStart = "${pkgs.nextdns}/bin/nextdns run ${escapeShellArgs config.services.nextdns.arguments}";
+        RestartSec = 120;
+        LimitMEMLOCK = "infinity";
+      };
+      after = [ "network.target" ];
+      before = [ "nss-lookup.target" ];
+      wants = [ "nss-lookup.target" ];
+      wantedBy = [ "multi-user.target" ];
+    };
+  };
+}
diff --git a/nixos/modules/services/networking/nghttpx/default.nix b/nixos/modules/services/networking/nghttpx/default.nix
index 881a2670f5db0..b8a0a24e3aad1 100644
--- a/nixos/modules/services/networking/nghttpx/default.nix
+++ b/nixos/modules/services/networking/nghttpx/default.nix
@@ -60,7 +60,7 @@ let
       # NB: nghttpx doesn't accept "tls", you must omit "no-tls" for
       # the default behavior of turning on TLS.
       params1 = lib.remove "tls" params0;
-          
+
       sections          = [ host] ++ params1;
       formattedSections = lib.concatStringsSep ";" sections;
     in
@@ -90,7 +90,7 @@ in
 { imports = [
     ./nghttpx-options.nix
   ];
-  
+
   config = lib.mkIf cfg.enable {
 
     users.groups.nghttpx = { };
@@ -98,7 +98,7 @@ in
       group = config.users.groups.nghttpx.name;
       isSystemUser = true;
     };
-      
+
 
     systemd.services = {
       nghttpx = {
diff --git a/nixos/modules/services/networking/nsd.nix b/nixos/modules/services/networking/nsd.nix
index 6e3eed0c55700..3ecbd06ee416b 100644
--- a/nixos/modules/services/networking/nsd.nix
+++ b/nixos/modules/services/networking/nsd.nix
@@ -11,8 +11,6 @@ let
 
   # build nsd with the options needed for the given config
   nsdPkg = pkgs.nsd.override {
-    configFile = "${configFile}/nsd.conf";
-
     bind8Stats = cfg.bind8Stats;
     ipv6 = cfg.ipv6;
     ratelimit = cfg.ratelimit.enable;
@@ -897,7 +895,10 @@ in
               + "want, please enable 'services.nsd.rootServer'.";
     };
 
-    environment.systemPackages = [ nsdPkg ];
+    environment = {
+      systemPackages = [ nsdPkg ];
+      etc."nsd/nsd.conf".source = "${configFile}/nsd.conf";
+    };
 
     users.groups.${username}.gid = config.ids.gids.nsd;
 
diff --git a/nixos/modules/services/networking/ntp/chrony.nix b/nixos/modules/services/networking/ntp/chrony.nix
index b7e4c89a155cd..78de50583f348 100644
--- a/nixos/modules/services/networking/ntp/chrony.nix
+++ b/nixos/modules/services/networking/ntp/chrony.nix
@@ -117,7 +117,6 @@ in
             ProtectHome = "yes";
             ProtectSystem = "full";
             PrivateTmp = "yes";
-            StateDirectory = "chrony";
           };
 
       };
diff --git a/nixos/modules/services/networking/nylon.nix b/nixos/modules/services/networking/nylon.nix
index 7c171281a9262..bfc358cb12fb1 100644
--- a/nixos/modules/services/networking/nylon.nix
+++ b/nixos/modules/services/networking/nylon.nix
@@ -140,7 +140,7 @@ in
     services.nylon = mkOption {
       default = {};
       description = "Collection of named nylon instances";
-      type = with types; loaOf (submodule nylonOpts);
+      type = with types; attrsOf (submodule nylonOpts);
       internal = true;
     };
 
diff --git a/nixos/modules/services/networking/onedrive.nix b/nixos/modules/services/networking/onedrive.nix
new file mode 100644
index 0000000000000..c52f920bae25e
--- /dev/null
+++ b/nixos/modules/services/networking/onedrive.nix
@@ -0,0 +1,72 @@
+{ config, lib, pkgs, ... }:
+let
+  cfg = config.services.onedrive;
+
+  onedriveLauncher =  pkgs.writeShellScriptBin
+    "onedrive-launcher"
+    ''
+      # XDG_CONFIG_HOME is not recognized in the environment here.
+      if [ -f $HOME/.config/onedrive-launcher ]
+      then
+        # Hopefully using underscore boundary helps locate variables
+        for _onedrive_config_dirname_ in $(cat $HOME/.config/onedrive-launcher | grep -v '[ \t]*#' )
+        do
+          systemctl --user start onedrive@$_onedrive_config_dirname_
+        done
+      else
+        systemctl --user start onedrive@onedrive
+      fi
+    ''
+  ;
+
+in {
+  ### Documentation
+  # meta.doc = ./onedrive.xml;
+
+  ### Interface
+
+  options.services.onedrive = {
+    enable = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      description = "Enable OneDrive service";
+    };
+
+     package = lib.mkOption {
+       type = lib.types.package;
+       default = pkgs.onedrive;
+       defaultText = "pkgs.onedrive";
+       example = lib.literalExample "pkgs.onedrive";
+       description = ''
+         OneDrive package to use.
+       '';
+     };
+  };
+### Implementation
+
+  config = lib.mkIf cfg.enable {
+    environment.systemPackages = [ cfg.package ];
+
+    systemd.user.services."onedrive@" = {
+      description = "Onedrive sync service";
+
+      serviceConfig = {
+        Type = "simple";
+        ExecStart = ''
+          ${cfg.package}/bin/onedrive --monitor --confdir=%h/.config/%i
+        '';
+        Restart="on-failure";
+        RestartSec=3;
+        RestartPreventExitStatus=3;
+      };
+    };
+
+    systemd.user.services.onedrive-launcher = {
+      wantedBy = [ "default.target" ];
+      serviceConfig = {
+        Type = "oneshot";
+        ExecStart = "${onedriveLauncher}/bin/onedrive-launcher";
+      };
+    };
+  };
+}
diff --git a/nixos/modules/services/networking/onedrive.xml b/nixos/modules/services/networking/onedrive.xml
new file mode 100644
index 0000000000000..5a9dcf01aeee9
--- /dev/null
+++ b/nixos/modules/services/networking/onedrive.xml
@@ -0,0 +1,34 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="onedrive">
+ <title>Microsoft OneDrive</title>
+ <para>
+  Microsoft Onedrive is a popular cloud file-hosting service, used by 85% of Fortune 500 companies. NixOS uses a popular OneDrive client for Linux maintained by github user abraunegg. The Linux client is excellent and allows customization of which files or paths to download, not much unlike the default Windows OneDrive client by Microsoft itself. The client allows syncing with multiple onedrive accounts at the same time, of any type- OneDrive personal, OneDrive business, Office365 and Sharepoint libraries, without any additional charge.
+ </para>
+ <para>
+  For more information, guides and documentation, see <link xlink:href="https://abraunegg.github.io/"/>.
+ </para>
+ <para>
+  To enable OneDrive support, add the following to your <filename>configuration.nix</filename>:
+<programlisting>
+<xref linkend="opt-services.onedrive.enable"/> = true;
+</programlisting>
+  This installs the <literal>onedrive</literal> package and a service <literal>onedriveLauncher</literal> which will instantiate a <literal>onedrive</literal> service for all your OneDrive accounts. Follow the steps in documentation of the onedrive client to setup your accounts. To use the service with multiple accounts, create a file named <filename>onedrive-launcher</filename> in <filename>~/.config</filename> and add the filename of the config directory, relative to <filename>~/.config</filename>. For example, if you have two OneDrive accounts with configs in <filename>~/.config/onedrive_bob_work</filename> and <filename>~/.config/onedrive_bob_personal</filename>, add the following lines:
+<programlisting>
+onedrive_bob_work
+# Not in use:
+# onedrive_bob_office365
+onedrive_bob_personal
+</programlisting>
+  No such file needs to be created if you are using only a single OneDrive account with config in the default location <filename>~/.config/onedrive</filename>, in the absence of <filename>~/.config/onedrive-launcher</filename>, only a single service is instantiated, with default config path.
+</para>
+
+  <para>
+  If you wish to use a custom OneDrive package, say from another channel, add the following line:
+<programlisting>
+<xref linkend="opt-services.onedrive.package"/> = pkgs.unstable.onedrive;
+</programlisting>
+ </para>
+</chapter>
diff --git a/nixos/modules/services/networking/openvpn.nix b/nixos/modules/services/networking/openvpn.nix
index dcd7e9e5fa4cd..650f9c84ac721 100644
--- a/nixos/modules/services/networking/openvpn.nix
+++ b/nixos/modules/services/networking/openvpn.nix
@@ -11,7 +11,7 @@ let
   makeOpenVPNJob = cfg: name:
     let
 
-      path = (getAttr "openvpn-${name}" config.systemd.services).path;
+      path = makeBinPath (getAttr "openvpn-${name}" config.systemd.services).path;
 
       upScript = ''
         #! /bin/sh
diff --git a/nixos/modules/services/networking/prosody.nix b/nixos/modules/services/networking/prosody.nix
index cdd341c9fb62e..a6c1cb0f4797a 100644
--- a/nixos/modules/services/networking/prosody.nix
+++ b/nixos/modules/services/networking/prosody.nix
@@ -655,7 +655,7 @@ in
 
         description = "Define the virtual hosts";
 
-        type = with types; loaOf (submodule vHostOpts);
+        type = with types; attrsOf (submodule vHostOpts);
 
         example = {
           myhost = {
@@ -772,7 +772,7 @@ in
       };
 
       disco_items = {
-      ${ lib.concatStringsSep "\n" (builtins.map (x: ''{ "${x.url}", "${x.description}"};'') discoItems)} 
+      ${ lib.concatStringsSep "\n" (builtins.map (x: ''{ "${x.url}", "${x.description}"};'') discoItems)}
       };
 
       allow_registration = ${toLua cfg.allowRegistration}
diff --git a/nixos/modules/services/networking/prosody.xml b/nixos/modules/services/networking/prosody.xml
index 7859cb1578b7e..471240cd14752 100644
--- a/nixos/modules/services/networking/prosody.xml
+++ b/nixos/modules/services/networking/prosody.xml
@@ -43,10 +43,10 @@ services.prosody = {
   <link linkend="opt-services.prosody.ssl.cert">ssl.cert</link> = "/var/lib/acme/example.org/fullchain.pem";
   <link linkend="opt-services.prosody.ssl.key">ssl.key</link> = "/var/lib/acme/example.org/key.pem";
   <link linkend="opt-services.prosody.virtualHosts">virtualHosts</link>."example.org" = {
-      <link linkend="opt-services.prosody.virtualHosts._name__.enabled">enabled</link> = true;
-      <link linkend="opt-services.prosody.virtualHosts._name__.domain">domain</link> = "example.org";
-      <link linkend="opt-services.prosody.virtualHosts._name__.ssl.cert">ssl.cert</link> = "/var/lib/acme/example.org/fullchain.pem";
-      <link linkend="opt-services.prosody.virtualHosts._name__.ssl.key">ssl.key</link> = "/var/lib/acme/example.org/key.pem";
+      <link linkend="opt-services.prosody.virtualHosts._name_.enabled">enabled</link> = true;
+      <link linkend="opt-services.prosody.virtualHosts._name_.domain">domain</link> = "example.org";
+      <link linkend="opt-services.prosody.virtualHosts._name_.ssl.cert">ssl.cert</link> = "/var/lib/acme/example.org/fullchain.pem";
+      <link linkend="opt-services.prosody.virtualHosts._name_.ssl.key">ssl.key</link> = "/var/lib/acme/example.org/key.pem";
   };
   <link linkend="opt-services.prosody.muc">muc</link> = [ {
       <link linkend="opt-services.prosody.muc">domain</link> = "conference.example.org";
@@ -65,7 +65,7 @@ services.prosody = {
    you'll need a single TLS certificate covering your main endpoint,
    the MUC one as well as the HTTP Upload one. We can generate such a
    certificate by leveraging the ACME
-   <link linkend="opt-security.acme.certs._name_.extraDomains">extraDomains</link> module option.
+   <link linkend="opt-security.acme.certs._name_.extraDomainNames">extraDomainNames</link> module option.
  </para>
  <para>
    Provided the setup detailed in the previous section, you'll need the following acme configuration to generate
@@ -78,8 +78,7 @@ security.acme = {
     "example.org" = {
       <link linkend="opt-security.acme.certs._name_.webroot">webroot</link> = "/var/www/example.org";
       <link linkend="opt-security.acme.certs._name_.email">email</link> = "root@example.org";
-      <link linkend="opt-security.acme.certs._name_.extraDomains">extraDomains."conference.example.org"</link> = null;
-      <link linkend="opt-security.acme.certs._name_.extraDomains">extraDomains."upload.example.org"</link> = null;
+      <link linkend="opt-security.acme.certs._name_.extraDomainNames">extraDomainNames</link> = [ "conference.example.org" "upload.example.org" ];
     };
   };
 };</programlisting>
diff --git a/nixos/modules/services/networking/radicale.nix b/nixos/modules/services/networking/radicale.nix
index 30bf22586f86f..5af035fd59e05 100644
--- a/nixos/modules/services/networking/radicale.nix
+++ b/nixos/modules/services/networking/radicale.nix
@@ -8,8 +8,10 @@ let
 
   confFile = pkgs.writeText "radicale.conf" cfg.config;
 
-  # This enables us to default to version 2 while still not breaking configurations of people with version 1
-  defaultPackage = if versionAtLeast config.system.stateVersion "17.09" then {
+  defaultPackage = if versionAtLeast config.system.stateVersion "20.09" then {
+    pkg = pkgs.radicale3;
+    text = "pkgs.radicale3";
+  } else if versionAtLeast config.system.stateVersion "17.09" then {
     pkg = pkgs.radicale2;
     text = "pkgs.radicale2";
   } else {
@@ -35,8 +37,9 @@ in
       defaultText = defaultPackage.text;
       description = ''
         Radicale package to use. This defaults to version 1.x if
-        <literal>system.stateVersion &lt; 17.09</literal> and version 2.x
-        otherwise.
+        <literal>system.stateVersion &lt; 17.09</literal>, version 2.x if
+        <literal>17.09 ≤ system.stateVersion &lt; 20.09</literal>, and
+        version 3.x otherwise.
       '';
     };
 
diff --git a/nixos/modules/services/networking/resilio.nix b/nixos/modules/services/networking/resilio.nix
index 004abc48219a2..6193d7340fc4a 100644
--- a/nixos/modules/services/networking/resilio.nix
+++ b/nixos/modules/services/networking/resilio.nix
@@ -30,12 +30,12 @@ let
     download_limit = cfg.downloadLimit;
     upload_limit = cfg.uploadLimit;
     lan_encrypt_data = cfg.encryptLAN;
-  } // optionalAttrs cfg.enableWebUI {
+  } // optionalAttrs (cfg.directoryRoot != "") { directory_root = cfg.directoryRoot; }
+    // optionalAttrs cfg.enableWebUI {
     webui = { listen = "${cfg.httpListenAddr}:${toString cfg.httpListenPort}"; } //
       (optionalAttrs (cfg.httpLogin != "") { login = cfg.httpLogin; }) //
       (optionalAttrs (cfg.httpPass != "") { password = cfg.httpPass; }) //
-      (optionalAttrs (cfg.apiKey != "") { api_key = cfg.apiKey; }) //
-      (optionalAttrs (cfg.directoryRoot != "") { directory_root = cfg.directoryRoot; });
+      (optionalAttrs (cfg.apiKey != "") { api_key = cfg.apiKey; });
   } // optionalAttrs (sharedFoldersRecord != []) {
     shared_folders = sharedFoldersRecord;
   }));
@@ -109,8 +109,8 @@ in
 
       httpListenAddr = mkOption {
         type = types.str;
-        default = "0.0.0.0";
-        example = "1.2.3.4";
+        default = "[::1]";
+        example = "0.0.0.0";
         description = ''
           HTTP address to bind to.
         '';
diff --git a/nixos/modules/services/networking/robustirc-bridge.nix b/nixos/modules/services/networking/robustirc-bridge.nix
new file mode 100644
index 0000000000000..255af79ec04b2
--- /dev/null
+++ b/nixos/modules/services/networking/robustirc-bridge.nix
@@ -0,0 +1,47 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.robustirc-bridge;
+in
+{
+  options = {
+    services.robustirc-bridge = {
+      enable = mkEnableOption "RobustIRC bridge";
+
+      extraFlags = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        description = ''Extra flags passed to the <command>robustirc-bridge</command> command. See <link xlink:href="https://robustirc.net/docs/adminguide.html#_bridge">RobustIRC Documentation</link> or robustirc-bridge(1) for details.'';
+        example = [
+          "-network robustirc.net"
+        ];
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.robustirc-bridge = {
+      description = "RobustIRC bridge";
+      documentation = [
+        "man:robustirc-bridge(1)"
+        "https://robustirc.net/"
+      ];
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+
+      serviceConfig = {
+        DynamicUser = true;
+        ExecStart = "${pkgs.robustirc-bridge}/bin/robustirc-bridge ${concatStringsSep " " cfg.extraFlags}";
+        Restart = "on-failure";
+
+        # Hardening
+        PrivateDevices = true;
+        ProtectSystem = true;
+        ProtectHome = true;
+        PrivateTmp = true;
+      };
+    };
+  };
+}
diff --git a/nixos/modules/services/networking/seeks.nix b/nixos/modules/services/networking/seeks.nix
deleted file mode 100644
index 40729225b6d0a..0000000000000
--- a/nixos/modules/services/networking/seeks.nix
+++ /dev/null
@@ -1,75 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-with lib;
-
-let
-
-  cfg = config.services.seeks;
-
-  confDir = cfg.confDir;
-
-  seeks = pkgs.seeks.override { seeks_confDir = confDir; };
-
-in
-
-{
-
-  ###### interface
-
-  options = {
-
-    services.seeks = {
-
-      enable = mkOption {
-        default = false;
-        type = types.bool;
-        description = "
-          Whether to enable the Seeks server.
-        ";
-      };
-
-      confDir = mkOption {
-        default = "";
-        type = types.str;
-        description = "
-          The Seeks server configuration. If it is not specified,
-          a default configuration is used.
-        ";
-      };
-
-    };
-
-  };
-
-
-  ###### implementation
-
-  config = mkIf config.services.seeks.enable {
-
-    users.users.seeks =
-      { uid = config.ids.uids.seeks;
-        description = "Seeks user";
-        createHome = true;
-        home = "/var/lib/seeks";
-      };
-
-    users.groups.seeks =
-      { gid = config.ids.gids.seeks;
-      };
-
-    systemd.services.seeks =
-      {
-        description = "Seeks server, the p2p search engine.";
-        after = [ "network.target" ];
-        wantedBy = [ "multi-user.target" ];
-        serviceConfig = {
-          User = "seeks";
-          ExecStart = "${seeks}/bin/seeks";
-        };
-      };
-
-    environment.systemPackages = [ seeks ];
-
-  };
-
-}
diff --git a/nixos/modules/services/networking/shadowsocks.nix b/nixos/modules/services/networking/shadowsocks.nix
index af12db590f000..d2541f9a6dffc 100644
--- a/nixos/modules/services/networking/shadowsocks.nix
+++ b/nixos/modules/services/networking/shadowsocks.nix
@@ -11,8 +11,13 @@ let
     method = cfg.encryptionMethod;
     mode = cfg.mode;
     user = "nobody";
-    fast_open = true;
-  } // optionalAttrs (cfg.password != null) { password = cfg.password; };
+    fast_open = cfg.fastOpen;
+  } // optionalAttrs (cfg.plugin != null) {
+    plugin = cfg.plugin;
+    plugin_opts = cfg.pluginOpts;
+  } // optionalAttrs (cfg.password != null) {
+    password = cfg.password;
+  } // cfg.extraConfig;
 
   configFile = pkgs.writeText "shadowsocks.json" (builtins.toJSON opts);
 
@@ -74,6 +79,14 @@ in
         '';
       };
 
+      fastOpen = mkOption {
+        type = types.bool;
+        default = true;
+        description = ''
+          use TCP fast-open
+        '';
+      };
+
       encryptionMethod = mkOption {
         type = types.str;
         default = "chacha20-ietf-poly1305";
@@ -82,6 +95,41 @@ in
         '';
       };
 
+      plugin = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        example = "\${pkgs.shadowsocks-v2ray-plugin}/bin/v2ray-plugin";
+        description = ''
+          SIP003 plugin for shadowsocks
+        '';
+      };
+
+      pluginOpts = mkOption {
+        type = types.str;
+        default = "";
+        example = "server;host=example.com";
+        description = ''
+          Options to pass to the plugin if one was specified
+        '';
+      };
+
+      extraConfig = mkOption {
+        type = types.attrs;
+        default = {};
+        example = ''
+          {
+            nameserver = "8.8.8.8";
+          }
+        '';
+        description = ''
+          Additional configuration for shadowsocks that is not covered by the
+          provided options. The provided attrset will be serialized to JSON and
+          has to contain valid shadowsocks options. Unfortunately most
+          additional options are undocumented but it's easy to find out what is
+          available by looking into the source code of
+          <link xlink:href="https://github.com/shadowsocks/shadowsocks-libev/blob/master/src/jconf.c"/>
+        '';
+      };
     };
 
   };
@@ -99,7 +147,7 @@ in
       description = "shadowsocks-libev Daemon";
       after = [ "network.target" ];
       wantedBy = [ "multi-user.target" ];
-      path = [ pkgs.shadowsocks-libev ] ++ optional (cfg.passwordFile != null) pkgs.jq;
+      path = [ pkgs.shadowsocks-libev ] ++ optional (cfg.plugin != null) cfg.plugin ++ optional (cfg.passwordFile != null) pkgs.jq;
       serviceConfig.PrivateTmp = true;
       script = ''
         ${optionalString (cfg.passwordFile != null) ''
diff --git a/nixos/modules/services/networking/skydns.nix b/nixos/modules/services/networking/skydns.nix
index e79d6de926449..ea466de932750 100644
--- a/nixos/modules/services/networking/skydns.nix
+++ b/nixos/modules/services/networking/skydns.nix
@@ -64,7 +64,7 @@ in {
     extraConfig = mkOption {
       default = {};
       type = types.attrsOf types.str;
-      description = "Skydns attribute set of extra config options passed as environemnt variables.";
+      description = "Skydns attribute set of extra config options passed as environment variables.";
     };
   };
 
diff --git a/nixos/modules/services/networking/ssh/sshd.nix b/nixos/modules/services/networking/ssh/sshd.nix
index 17f31e3a488d8..5365b8b9b1072 100644
--- a/nixos/modules/services/networking/ssh/sshd.nix
+++ b/nixos/modules/services/networking/ssh/sshd.nix
@@ -232,6 +232,14 @@ in
         '';
       };
 
+      banner = mkOption {
+        type = types.nullOr types.lines;
+        default = null;
+        description = ''
+          Message to display to the remote user before authentication is allowed.
+        '';
+      };
+
       authorizedKeysFiles = mkOption {
         type = types.listOf types.str;
         default = [];
@@ -361,7 +369,7 @@ in
     };
 
     users.users = mkOption {
-      type = with types; loaOf (submodule userOptions);
+      type = with types; attrsOf (submodule userOptions);
     };
 
   };
@@ -474,6 +482,8 @@ in
       ''
         UsePAM yes
 
+        Banner ${if cfg.banner == null then "none" else pkgs.writeText "ssh_banner" cfg.banner}
+
         AddressFamily ${if config.networking.enableIPv6 then "any" else "inet"}
         ${concatMapStrings (port: ''
           Port ${toString port}
diff --git a/nixos/modules/services/networking/sslh.nix b/nixos/modules/services/networking/sslh.nix
index c4fa370a5fef3..0921febba668a 100644
--- a/nixos/modules/services/networking/sslh.nix
+++ b/nixos/modules/services/networking/sslh.nix
@@ -15,7 +15,11 @@ let
 
     listen:
     (
-      { host: "${cfg.listenAddress}"; port: "${toString cfg.port}"; }
+      ${
+        concatMapStringsSep ",\n"
+        (addr: ''{ host: "${addr}"; port: "${toString cfg.port}"; }'')
+        cfg.listenAddresses
+      }
     );
 
     ${cfg.appendConfig}
@@ -33,6 +37,10 @@ let
   '';
 in
 {
+  imports = [
+    (mkRenamedOptionModule [ "services" "sslh" "listenAddress" ] [ "services" "sslh" "listenAddresses" ])
+  ];
+
   options = {
     services.sslh = {
       enable = mkEnableOption "sslh";
@@ -55,10 +63,10 @@ in
         description = "Will the services behind sslh (Apache, sshd and so on) see the external IP and ports as if the external world connected directly to them";
       };
 
-      listenAddress = mkOption {
-        type = types.str;
-        default = "0.0.0.0";
-        description = "Listening address or hostname.";
+      listenAddresses = mkOption {
+        type = types.coercedTo types.str singleton (types.listOf types.str);
+        default = [ "0.0.0.0" "[::]" ];
+        description = "Listening addresses or hostnames.";
       };
 
       port = mkOption {
diff --git a/nixos/modules/services/networking/supplicant.nix b/nixos/modules/services/networking/supplicant.nix
index b5b9989ce1863..20704be9b36fe 100644
--- a/nixos/modules/services/networking/supplicant.nix
+++ b/nixos/modules/services/networking/supplicant.nix
@@ -76,9 +76,9 @@ in
     networking.supplicant = mkOption {
       type = with types; attrsOf (submodule {
         options = {
-  
+
           configFile = {
-  
+
             path = mkOption {
               type = types.nullOr types.path;
               default = null;
@@ -89,7 +89,7 @@ in
                 precedence over options defined in <literal>configFile</literal>.
               '';
             };
-  
+
             writable = mkOption {
               type = types.bool;
               default = false;
@@ -98,9 +98,9 @@ in
                 <literal>wpa_supplicant</literal>.
               '';
             };
-  
+
           };
-  
+
           extraConf = mkOption {
             type = types.lines;
             default = "";
@@ -126,7 +126,7 @@ in
               use the <literal>configFile</literal> instead.
             '';
           };
-  
+
           extraCmdArgs = mkOption {
             type = types.str;
             default = "";
@@ -134,21 +134,21 @@ in
             description =
               "Command line arguments to add when executing <literal>wpa_supplicant</literal>.";
           };
-  
+
           driver = mkOption {
             type = types.nullOr types.str;
             default = "nl80211,wext";
             description = "Force a specific wpa_supplicant driver.";
           };
-  
+
           bridge = mkOption {
             type = types.str;
             default = "";
             description = "Name of the bridge interface that wpa_supplicant should listen at.";
           };
-  
+
           userControlled = {
-  
+
             enable = mkOption {
               type = types.bool;
               default = false;
@@ -159,20 +159,20 @@ in
                 access points.
               '';
             };
-  
+
             socketDir = mkOption {
               type = types.str;
               default = "/run/wpa_supplicant";
               description = "Directory of sockets for controlling wpa_supplicant.";
             };
-  
+
             group = mkOption {
               type = types.str;
               default = "wheel";
               example = "network";
               description = "Members of this group can control wpa_supplicant.";
             };
-  
+
           };
         };
       });
diff --git a/nixos/modules/services/networking/syncthing.nix b/nixos/modules/services/networking/syncthing.nix
index e717d78feed57..28348c7893a0d 100644
--- a/nixos/modules/services/networking/syncthing.nix
+++ b/nixos/modules/services/networking/syncthing.nix
@@ -18,6 +18,7 @@ let
     fsWatcherEnabled = folder.watch;
     fsWatcherDelayS = folder.watchDelay;
     ignorePerms = folder.ignorePerms;
+    ignoreDelete = folder.ignoreDelete;
     versioning = folder.versioning;
   }) (filterAttrs (
     _: folder:
@@ -284,8 +285,6 @@ in {
                 });
               };
 
-
-
               rescanInterval = mkOption {
                 type = types.int;
                 default = 3600;
@@ -327,6 +326,16 @@ in {
                 '';
               };
 
+              ignoreDelete = mkOption {
+                type = types.bool;
+                default = false;
+                description = ''
+                  Whether to delete files in destination. See <link
+                  xlink:href="https://docs.syncthing.net/advanced/folder-ignoredelete.html">
+                  upstream's docs</link>.
+                '';
+              };
+
             };
           }));
         };
diff --git a/nixos/modules/services/networking/tinc.nix b/nixos/modules/services/networking/tinc.nix
index e98aafc209372..725bd9bf9403b 100644
--- a/nixos/modules/services/networking/tinc.nix
+++ b/nixos/modules/services/networking/tinc.nix
@@ -48,6 +48,14 @@ in
               '';
             };
 
+            rsaPrivateKeyFile = mkOption {
+              default = null;
+              type = types.nullOr types.path;
+              description = ''
+                Path of the private RSA keyfile.
+              '';
+            };
+
             debugLevel = mkOption {
               default = 0;
               type = types.addCheck types.int (l: l >= 0 && l <= 5);
@@ -139,6 +147,7 @@ in
               Name = ${if data.name == null then "$HOST" else data.name}
               DeviceType = ${data.interfaceType}
               ${optionalString (data.ed25519PrivateKeyFile != null) "Ed25519PrivateKeyFile = ${data.ed25519PrivateKeyFile}"}
+              ${optionalString (data.rsaPrivateKeyFile != null) "PrivateKeyFile = ${data.rsaPrivateKeyFile}"}
               ${optionalString (data.listenAddress != null) "ListenAddress = ${data.listenAddress}"}
               ${optionalString (data.bindToAddress != null) "BindToAddress = ${data.bindToAddress}"}
               Interface = tinc.${network}
@@ -170,12 +179,15 @@ in
           # Determine how we should generate our keys
           if type tinc >/dev/null 2>&1; then
             # Tinc 1.1+ uses the tinc helper application for key generation
-          ${if data.ed25519PrivateKeyFile != null then "  # Keyfile managed by nix" else ''
+          ${if data.ed25519PrivateKeyFile != null then "  # ed25519 Keyfile managed by nix" else ''
             # Prefer ED25519 keys (only in 1.1+)
             [ -f "/etc/tinc/${network}/ed25519_key.priv" ] || tinc -n ${network} generate-ed25519-keys
           ''}
-            # Otherwise use RSA keys
+          ${if data.rsaPrivateKeyFile != null then "  # RSA Keyfile managed by nix" else ''
             [ -f "/etc/tinc/${network}/rsa_key.priv" ] || tinc -n ${network} generate-rsa-keys 4096
+          ''}
+            # In case there isn't anything to do
+            true
           else
             # Tinc 1.0 uses the tincd application
             [ -f "/etc/tinc/${network}/rsa_key.priv" ] || tincd -n ${network} -K 4096
diff --git a/nixos/modules/services/networking/trickster.nix b/nixos/modules/services/networking/trickster.nix
index 8760dd5a93827..49c945adb80f3 100644
--- a/nixos/modules/services/networking/trickster.nix
+++ b/nixos/modules/services/networking/trickster.nix
@@ -106,7 +106,8 @@ in
         Restart = "always";
       };
     };
+  };
 
-  };  
-}
+  meta.maintainers = with maintainers; [ _1000101 ];
 
+}
diff --git a/nixos/modules/services/networking/unifi.nix b/nixos/modules/services/networking/unifi.nix
index 4bdfa8143dce0..62bcf7a149726 100644
--- a/nixos/modules/services/networking/unifi.nix
+++ b/nixos/modules/services/networking/unifi.nix
@@ -162,6 +162,8 @@ in
       unitConfig.RequiresMountsFor = stateDir;
       # This a HACK to fix missing dependencies of dynamic libs extracted from jars
       environment.LD_LIBRARY_PATH = with pkgs.stdenv; "${cc.cc.lib}/lib";
+      # Make sure package upgrades trigger a service restart
+      restartTriggers = [ cfg.unifiPackage cfg.mongodbPackage ];
 
       serviceConfig = {
         Type = "simple";
diff --git a/nixos/modules/services/networking/wasabibackend.nix b/nixos/modules/services/networking/wasabibackend.nix
new file mode 100644
index 0000000000000..6eacffe709b0d
--- /dev/null
+++ b/nixos/modules/services/networking/wasabibackend.nix
@@ -0,0 +1,158 @@
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.services.wasabibackend;
+
+  inherit (lib) mkEnableOption mkIf mkOption optionalAttrs optionalString types;
+
+  confOptions = {
+      BitcoinRpcConnectionString = "${cfg.rpc.user}:${cfg.rpc.password}";
+  } // optionalAttrs (cfg.network == "mainnet") {
+      Network = "Main";
+      MainNetBitcoinP2pEndPoint = "${cfg.endpoint.ip}:${toString cfg.endpoint.port}";
+      MainNetBitcoinCoreRpcEndPoint = "${cfg.rpc.ip}:${toString cfg.rpc.port}";
+  } // optionalAttrs (cfg.network == "testnet") {
+      Network = "TestNet";
+      TestNetBitcoinP2pEndPoint = "${cfg.endpoint.ip}:${toString cfg.endpoint.port}";
+      TestNetBitcoinCoreRpcEndPoint = "${cfg.rpc.ip}:${toString cfg.rpc.port}";
+  } // optionalAttrs (cfg.network == "regtest") {
+      Network = "RegTest";
+      RegTestBitcoinP2pEndPoint = "${cfg.endpoint.ip}:${toString cfg.endpoint.port}";
+      RegTestBitcoinCoreRpcEndPoint = "${cfg.rpc.ip}:${toString cfg.rpc.port}";
+  };
+
+	configFile = pkgs.writeText "wasabibackend.conf" (builtins.toJSON confOptions);
+
+in {
+
+  options = {
+
+    services.wasabibackend = {
+      enable = mkEnableOption "Wasabi backend service";
+
+      dataDir = mkOption {
+        type = types.path;
+        default = "/var/lib/wasabibackend";
+        description = "The data directory for the Wasabi backend node.";
+      };
+
+      customConfigFile = mkOption {
+        type = types.nullOr types.path;
+        default = null;
+        description = "Defines the path to a custom configuration file that is copied to the user's directory. Overrides any config options.";
+      };
+
+      network = mkOption {
+        type = types.enum [ "mainnet" "testnet" "regtest" ];
+        default = "mainnet";
+        description = "The network to use for the Wasabi backend service.";
+      };
+
+      endpoint = {
+        ip = mkOption {
+          type = types.str;
+          default = "127.0.0.1";
+          description = "IP address for P2P connection to bitcoind.";
+        };
+
+        port = mkOption {
+          type = types.port;
+          default = 8333;
+          description = "Port for P2P connection to bitcoind.";
+        };
+      };
+
+      rpc = {
+        ip = mkOption {
+          type = types.str;
+          default = "127.0.0.1";
+          description = "IP address for RPC connection to bitcoind.";
+        };
+
+        port = mkOption {
+          type = types.port;
+          default = 8332;
+          description = "Port for RPC connection to bitcoind.";
+        };
+
+        user = mkOption {
+          type = types.str;
+          default = "bitcoin";
+          description = "RPC user for the bitcoin endpoint.";
+        };
+
+        password = mkOption {
+          type = types.str;
+          default = "password";
+          description = "RPC password for the bitcoin endpoint. Warning: this is stored in cleartext in the Nix store! Use <literal>configFile</literal> or <literal>passwordFile</literal> if needed.";
+        };
+
+        passwordFile = mkOption {
+          type = types.nullOr types.path;
+          default = null;
+          description = "File that contains the password of the RPC user.";
+        };
+      };
+
+      user = mkOption {
+        type = types.str;
+        default = "wasabibackend";
+        description = "The user as which to run the wasabibackend node.";
+      };
+
+      group = mkOption {
+        type = types.str;
+        default = cfg.user;
+        description = "The group as which to run the wasabibackend node.";
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+
+    systemd.tmpfiles.rules = [
+      "d '${cfg.dataDir}' 0770 '${cfg.user}' '${cfg.group}' - -"
+    ];
+
+    systemd.services.wasabibackend = {
+      description = "wasabibackend server";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network-online.target" ];
+      environment = {
+        DOTNET_PRINT_TELEMETRY_MESSAGE = "false";
+        DOTNET_CLI_TELEMETRY_OPTOUT = "true";
+      };
+      preStart = ''
+        mkdir -p ${cfg.dataDir}/.walletwasabi/backend
+        ${if cfg.customConfigFile != null then ''
+          cp -v ${cfg.customConfigFile} ${cfg.dataDir}/.walletwasabi/backend/Config.json
+        '' else ''
+          cp -v ${configFile} ${cfg.dataDir}/.walletwasabi/backend/Config.json
+          ${optionalString (cfg.rpc.passwordFile != null) ''
+            CONFIGTMP=$(mktemp)
+            cat ${cfg.dataDir}/.walletwasabi/backend/Config.json | ${pkgs.jq}/bin/jq --arg rpconnection "${cfg.rpc.user}:$(cat "${cfg.rpc.passwordFile}")" '. + { BitcoinRpcConnectionString: $rpconnection }' > $CONFIGTMP
+            mv $CONFIGTMP ${cfg.dataDir}/.walletwasabi/backend/Config.json
+          ''}
+        ''}
+        chmod ug+w ${cfg.dataDir}/.walletwasabi/backend/Config.json
+      '';
+      serviceConfig = {
+        User = cfg.user;
+        Group = cfg.group;
+        ExecStart = "${pkgs.wasabibackend}/bin/WasabiBackend";
+        ProtectSystem = "full";
+      };
+    };
+
+    users.users.${cfg.user} = {
+      name = cfg.user;
+      group = cfg.group;
+      description = "wasabibackend daemon user";
+      home = cfg.dataDir;
+      isSystemUser = true;
+    };
+
+    users.groups.${cfg.group} = {};
+
+  };
+}
diff --git a/nixos/modules/services/networking/websockify.nix b/nixos/modules/services/networking/websockify.nix
index d9177df65bd62..27cb47be12f7e 100644
--- a/nixos/modules/services/networking/websockify.nix
+++ b/nixos/modules/services/networking/websockify.nix
@@ -5,12 +5,12 @@ with lib;
 let cfg = config.services.networking.websockify; in {
   options = {
     services.networking.websockify = {
-      enable = mkOption {  
+      enable = mkOption {
         description = "Whether to enable websockify to forward websocket connections to TCP connections.";
 
-        default = false;   
+        default = false;
 
-        type = types.bool; 
+        type = types.bool;
       };
 
       sslCert = mkOption {
diff --git a/nixos/modules/services/networking/wg-quick.nix b/nixos/modules/services/networking/wg-quick.nix
index ff1bdeed9f481..02fe40a22a102 100644
--- a/nixos/modules/services/networking/wg-quick.nix
+++ b/nixos/modules/services/networking/wg-quick.nix
@@ -29,7 +29,7 @@ let
         type = with types; nullOr str;
         default = null;
         description = ''
-          Base64 private key generated by wg genkey.
+          Base64 private key generated by <command>wg genkey</command>.
 
           Warning: Consider using privateKeyFile instead if you do not
           want to store the key in the world-readable Nix store.
@@ -41,7 +41,7 @@ let
         type = with types; nullOr str;
         default = null;
         description = ''
-          Private key file as generated by wg genkey.
+          Private key file as generated by <command>wg genkey</command>.
         '';
       };
 
@@ -106,9 +106,9 @@ let
         description = ''
           The kernel routing table to add this interface's
           associated routes to. Setting this is useful for e.g. policy routing
-          ("ip rule") or virtual routing and forwarding ("ip vrf"). Both numeric
-          table IDs and table names (/etc/rt_tables) can be used. Defaults to
-          "main".
+          ("ip rule") or virtual routing and forwarding ("ip vrf"). Both
+          numeric table IDs and table names (/etc/rt_tables) can be used.
+          Defaults to "main".
         '';
       };
 
@@ -139,7 +139,7 @@ let
       publicKey = mkOption {
         example = "xTIBA5rboUvnH4htodjb6e697QjLERt1NAB4mZqp8Dg=";
         type = types.str;
-        description = "The base64 public key the peer.";
+        description = "The base64 public key to the peer.";
       };
 
       presharedKey = mkOption {
@@ -147,8 +147,8 @@ let
         example = "rVXs/Ni9tu3oDBLS4hOyAUAa1qTWVA3loR8eL20os3I=";
         type = with types; nullOr str;
         description = ''
-          Base64 preshared key generated by wg genpsk. Optional,
-          and may be omitted. This option adds an additional layer of
+          Base64 preshared key generated by <command>wg genpsk</command>.
+          Optional, and may be omitted. This option adds an additional layer of
           symmetric-key cryptography to be mixed into the already existing
           public-key cryptography, for post-quantum resistance.
 
@@ -162,8 +162,8 @@ let
         example = "/private/wireguard_psk";
         type = with types; nullOr str;
         description = ''
-          File pointing to preshared key as generated by wg pensk. Optional,
-          and may be omitted. This option adds an additional layer of
+          File pointing to preshared key as generated by <command>wg genpsk</command>.
+          Optional, and may be omitted. This option adds an additional layer of
           symmetric-key cryptography to be mixed into the already existing
           public-key cryptography, for post-quantum resistance.
         '';
diff --git a/nixos/modules/services/networking/wireguard.nix b/nixos/modules/services/networking/wireguard.nix
index e8f83f6dd8bf8..e07020349cf4f 100644
--- a/nixos/modules/services/networking/wireguard.nix
+++ b/nixos/modules/services/networking/wireguard.nix
@@ -91,11 +91,13 @@ let
       table = mkOption {
         default = "main";
         type = types.str;
-        description = ''The kernel routing table to add this interface's
-        associated routes to. Setting this is useful for e.g. policy routing
-        ("ip rule") or virtual routing and forwarding ("ip vrf"). Both numeric
-        table IDs and table names (/etc/rt_tables) can be used. Defaults to
-        "main".'';
+        description = ''
+          The kernel routing table to add this interface's
+          associated routes to. Setting this is useful for e.g. policy routing
+          ("ip rule") or virtual routing and forwarding ("ip vrf"). Both
+          numeric table IDs and table names (/etc/rt_tables) can be used.
+          Defaults to "main".
+        '';
       };
 
       peers = mkOption {
@@ -174,7 +176,7 @@ let
         example = "/private/wireguard_psk";
         type = with types; nullOr str;
         description = ''
-          File pointing to preshared key as generated by <command>wg pensk</command>.
+          File pointing to preshared key as generated by <command>wg genpsk</command>.
           Optional, and may be omitted. This option adds an additional layer of
           symmetric-key cryptography to be mixed into the already existing
           public-key cryptography, for post-quantum resistance.
@@ -217,7 +219,6 @@ let
 
   };
 
-
   generatePathUnit = name: values:
     assert (values.privateKey == null);
     assert (values.privateKeyFile != null);
diff --git a/nixos/modules/services/networking/wpa_supplicant.nix b/nixos/modules/services/networking/wpa_supplicant.nix
index a7dea95056a0e..395139879036a 100644
--- a/nixos/modules/services/networking/wpa_supplicant.nix
+++ b/nixos/modules/services/networking/wpa_supplicant.nix
@@ -4,7 +4,7 @@ with lib;
 
 let
   cfg = config.networking.wireless;
-  configFile = if cfg.networks != {} then pkgs.writeText "wpa_supplicant.conf" ''
+  configFile = if cfg.networks != {} || cfg.extraConfig != "" || cfg.userControlled.enable then pkgs.writeText "wpa_supplicant.conf" ''
     ${optionalString cfg.userControlled.enable ''
       ctrl_interface=DIR=/run/wpa_supplicant GROUP=${cfg.userControlled.group}
       update_config=1''}
@@ -233,6 +233,9 @@ in {
       path = [ pkgs.wpa_supplicant ];
 
       script = ''
+        if [ -f /etc/wpa_supplicant.conf -a "/etc/wpa_supplicant.conf" != "${configFile}" ]
+        then echo >&2 "<3>/etc/wpa_supplicant.conf present but ignored. Generated ${configFile} is used instead."
+        fi
         iface_args="-s -u -D${cfg.driver} -c ${configFile}"
         ${if ifaces == [] then ''
           for i in $(cd /sys/class/net && echo *); do
diff --git a/nixos/modules/services/networking/xandikos.nix b/nixos/modules/services/networking/xandikos.nix
index 87c029156b9e7..3c40bb956f57e 100644
--- a/nixos/modules/services/networking/xandikos.nix
+++ b/nixos/modules/services/networking/xandikos.nix
@@ -90,7 +90,7 @@ in
   config = mkIf cfg.enable (
     mkMerge [
       {
-        meta.maintainers = [ lib.maintainers."0x4A6F" ];
+        meta.maintainers = with lib.maintainers; [ _0x4A6F ];
 
         systemd.services.xandikos = {
           description = "A Simple Calendar and Contact Server";
@@ -122,7 +122,7 @@ in
             ExecStart = ''
               ${cfg.package}/bin/xandikos \
                 --directory /var/lib/xandikos \
-                --listen_address ${cfg.address} \
+                --listen-address ${cfg.address} \
                 --port ${toString cfg.port} \
                 --route-prefix ${cfg.routePrefix} \
                 ${lib.concatStringsSep " " cfg.extraOptions}
diff --git a/nixos/modules/services/networking/yggdrasil.nix b/nixos/modules/services/networking/yggdrasil.nix
index 0fe9a200a1b60..a71c635c9f6ef 100644
--- a/nixos/modules/services/networking/yggdrasil.nix
+++ b/nixos/modules/services/networking/yggdrasil.nix
@@ -195,5 +195,8 @@ in {
     # Make yggdrasilctl available on the command line.
     environment.systemPackages = [ cfg.package ];
   });
-  meta.maintainers = with lib.maintainers; [ gazally ehmry ];
+  meta = {
+    doc = ./yggdrasil.xml;
+    maintainers = with lib.maintainers; [ gazally ehmry ];
+  };
 }
diff --git a/nixos/modules/services/networking/yggdrasil.xml b/nixos/modules/services/networking/yggdrasil.xml
new file mode 100644
index 0000000000000..c012cd4a92949
--- /dev/null
+++ b/nixos/modules/services/networking/yggdrasil.xml
@@ -0,0 +1,157 @@
+<?xml version="1.0"?>
+<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xi="http://www.w3.org/2001/XInclude" version="5.0" xml:id="module-services-networking-yggdrasil">
+  <title>Yggdrasil</title>
+  <para>
+    <emphasis>Source:</emphasis>
+    <filename>modules/services/networking/yggdrasil/default.nix</filename>
+  </para>
+  <para>
+    <emphasis>Upstream documentation:</emphasis>
+    <link xlink:href="https://yggdrasil-network.github.io/"/>
+  </para>
+  <para>
+Yggdrasil is an early-stage implementation of a fully end-to-end encrypted,
+self-arranging IPv6 network.
+</para>
+  <section xml:id="module-services-networking-yggdrasil-configuration">
+    <title>Configuration</title>
+    <section xml:id="module-services-networking-yggdrasil-configuration-simple">
+      <title>Simple ephemeral node</title>
+      <para>
+An annotated example of a simple configuration:
+<programlisting>
+{
+  services.yggdrasil = {
+    enable = true;
+    persistentKeys = false;
+      # The NixOS module will generate new keys and a new IPv6 address each time
+      # it is started if persistentKeys is not enabled.
+
+    config = {
+      Peers = [
+        # Yggdrasil will automatically connect and "peer" with other nodes it
+        # discovers via link-local multicast annoucements. Unless this is the
+        # case (it probably isn't) a node needs peers within the existing
+        # network that it can tunnel to.
+        "tcp://1.2.3.4:1024"
+        "tcp://1.2.3.5:1024"
+        # Public peers can be found at
+        # https://github.com/yggdrasil-network/public-peers
+      ];
+    };
+  };
+}
+</programlisting>
+   </para>
+    </section>
+    <section xml:id="module-services-networking-yggdrasil-configuration-prefix">
+      <title>Persistent node with prefix</title>
+      <para>
+A node with a fixed address that announces a prefix:
+<programlisting>
+let
+  address = "210:5217:69c0:9afc:1b95:b9f:8718:c3d2";
+  prefix = "310:5217:69c0:9afc";
+  # taken from the output of "yggdrasilctl getself".
+in {
+
+  services.yggdrasil = {
+    enable = true;
+    persistentKeys = true; # Maintain a fixed public key and IPv6 address.
+    config = {
+      Peers = [ "tcp://1.2.3.4:1024" "tcp://1.2.3.5:1024" ];
+      NodeInfo = {
+        # This information is visible to the network.
+        name = config.networking.hostName;
+        location = "The North Pole";
+      };
+    };
+  };
+
+  boot.kernel.sysctl."net.ipv6.conf.all.forwarding" = 1;
+    # Forward traffic under the prefix.
+
+  networking.interfaces.${eth0}.ipv6.addresses = [{
+    # Set a 300::/8 address on the local physical device.
+    address = prefix + "::1";
+    prefixLength = 64;
+  }];
+
+  services.radvd = {
+    # Annouce the 300::/8 prefix to eth0.
+    enable = true;
+    config = ''
+      interface eth0
+      {
+        AdvSendAdvert on;
+        AdvDefaultLifetime 0;
+        prefix ${prefix}::/64 {
+          AdvOnLink on;
+          AdvAutonomous on;
+        };
+        route 200::/8 {};
+      };
+    '';
+  };
+}
+</programlisting>
+  </para>
+    </section>
+    <section xml:id="module-services-networking-yggdrasil-configuration-container">
+      <title>Yggdrasil attached Container</title>
+      <para>
+A NixOS container attached to the Yggdrasil network via a node running on the
+host:
+        <programlisting>
+let
+  yggPrefix64 = "310:5217:69c0:9afc";
+    # Again, taken from the output of "yggdrasilctl getself".
+in
+{
+  boot.kernel.sysctl."net.ipv6.conf.all.forwarding" = 1;
+  # Enable IPv6 forwarding.
+
+  networking = {
+    bridges.br0.interfaces = [ ];
+    # A bridge only to containers&#x2026;
+
+    interfaces.br0 = {
+      # &#x2026; configured with a prefix address.
+      ipv6.addresses = [{
+        address = "${yggPrefix64}::1";
+        prefixLength = 64;
+      }];
+    };
+  };
+
+  containers.foo = {
+    autoStart = true;
+    privateNetwork = true;
+    hostBridge = "br0";
+    # Attach the container to the bridge only.
+    config = { config, pkgs, ... }: {
+      networking.interfaces.eth0.ipv6 = {
+        addresses = [{
+          # Configure a prefix address.
+          address = "${yggPrefix64}::2";
+          prefixLength = 64;
+        }];
+        routes = [{
+          # Configure the prefix route.
+          address = "200::";
+          prefixLength = 7;
+          via = "${yggPrefix64}::1";
+        }];
+      };
+
+      services.httpd.enable = true;
+      networking.firewall.allowedTCPPorts = [ 80 ];
+    };
+  };
+
+}
+</programlisting>
+      </para>
+    </section>
+  </section>
+</chapter>
diff --git a/nixos/modules/services/scheduling/chronos.nix b/nixos/modules/services/scheduling/chronos.nix
deleted file mode 100644
index 9a8ed4c09ac1c..0000000000000
--- a/nixos/modules/services/scheduling/chronos.nix
+++ /dev/null
@@ -1,54 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-with lib;
-
-let
-  cfg = config.services.chronos;
-
-in {
-
-  ###### interface
-
-  options.services.chronos = {
-    enable = mkOption {
-      description = "Whether to enable graphite web frontend.";
-      default = false;
-      type = types.bool;
-    };
-
-    httpPort = mkOption {
-      description = "Chronos listening port";
-      default = 4400;
-      type = types.int;
-    };
-
-    master = mkOption {
-      description = "Chronos mesos master zookeeper address";
-      default = "zk://${head cfg.zookeeperHosts}/mesos";
-      type = types.str;
-    };
-
-    zookeeperHosts = mkOption {
-      description = "Chronos mesos zookepper addresses";
-      default = [ "localhost:2181" ];
-      type = types.listOf types.str;
-    };
-  };
-
-  ###### implementation
-
-  config = mkIf cfg.enable {
-    systemd.services.chronos = {
-      description = "Chronos Service";
-      wantedBy = [ "multi-user.target" ];
-      after = [ "network.target" "zookeeper.service" ];
-
-      serviceConfig = {
-        ExecStart = "${pkgs.chronos}/bin/chronos --master ${cfg.master} --zk_hosts ${concatStringsSep "," cfg.zookeeperHosts} --http_port ${toString cfg.httpPort}";
-        User = "chronos";
-      };
-    };
-
-    users.users.chronos.uid = config.ids.uids.chronos;
-  };
-}
diff --git a/nixos/modules/services/scheduling/marathon.nix b/nixos/modules/services/scheduling/marathon.nix
deleted file mode 100644
index 2e0d20c64b23a..0000000000000
--- a/nixos/modules/services/scheduling/marathon.nix
+++ /dev/null
@@ -1,98 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-with lib;
-
-let
-
-  cfg = config.services.marathon;
-
-in {
-
-  ###### interface
-
-  options.services.marathon = {
-    enable = mkOption {
-      type = types.bool;
-      default = false;
-      description = ''
-	Whether to enable the marathon mesos framework.
-      '';
-    };
-
-    master = mkOption {
-      type = types.str;
-      default = "zk://${concatStringsSep "," cfg.zookeeperHosts}/mesos";
-      example = "zk://1.2.3.4:2181,2.3.4.5:2181,3.4.5.6:2181/mesos";
-      description = ''
-	Mesos master address. See <link xlink:href="https://mesosphere.github.io/marathon/docs/"/> for details.
-      '';
-    };
-
-    zookeeperHosts = mkOption {
-      type = types.listOf types.str;
-      default = [ "localhost:2181" ];
-      example = [ "1.2.3.4:2181" "2.3.4.5:2181" "3.4.5.6:2181" ];
-      description = ''
-	ZooKeeper hosts' addresses.
-      '';
-    };
-
-    user = mkOption {
-      type = types.str;
-      default = "marathon";
-      example = "root";
-      description = ''
-	The user that the Marathon framework will be launched as. If the user doesn't exist it will be created.
-	If you want to run apps that require root access or you want to launch apps using arbitrary users, that
-	is using the `--mesos_user` flag then you need to change this to `root`.
-      '';
-    };
-
-    httpPort = mkOption {
-      type = types.int;
-      default = 8080;
-      description = ''
-	Marathon listening port for HTTP connections.
-      '';
-    };
-
-    extraCmdLineOptions = mkOption {
-      type = types.listOf types.str;
-      default = [ ];
-      example = [ "--https_port=8443" "--zk_timeout=10000" "--marathon_store_timeout=2000" ];
-      description = ''
-	Extra command line options to pass to Marathon.
-	See <link xlink:href="https://mesosphere.github.io/marathon/docs/command-line-flags.html"/> for all possible flags.
-      '';
-    };
-
-    environment = mkOption {
-      default = { };
-      type = types.attrs;
-      example = { JAVA_OPTS = "-Xmx512m"; MESOSPHERE_HTTP_CREDENTIALS = "username:password"; };
-      description = ''
-	Environment variables passed to Marathon.
-      '';
-    };
-  };
-
-  ###### implementation
-
-  config = mkIf cfg.enable {
-    systemd.services.marathon = {
-      description = "Marathon Service";
-      environment = cfg.environment;
-      wantedBy = [ "multi-user.target" ];
-      after = [ "network.target" "zookeeper.service" "mesos-master.service" "mesos-slave.service" ];
-
-      serviceConfig = {
-        ExecStart = "${pkgs.marathon}/bin/marathon --master ${cfg.master} --zk zk://${concatStringsSep "," cfg.zookeeperHosts}/marathon --http_port ${toString cfg.httpPort} ${concatStringsSep " " cfg.extraCmdLineOptions}";
-        User = cfg.user;
-        Restart = "always";
-        RestartSec = "2";
-      };
-    };
-
-    users.users.${cfg.user}.isSystemUser = true;
-  };
-}
diff --git a/nixos/modules/services/security/bitwarden_rs/default.nix b/nixos/modules/services/security/bitwarden_rs/default.nix
index 903a532703774..a04bc883bf0f7 100644
--- a/nixos/modules/services/security/bitwarden_rs/default.nix
+++ b/nixos/modules/services/security/bitwarden_rs/default.nix
@@ -81,6 +81,23 @@ in {
         <link xlink:href="https://github.com/dani-garcia/bitwarden_rs/blob/${bitwarden_rs.version}/.env.template">the environment template file</link>.
       '';
     };
+
+    environmentFile = mkOption {
+      type = with types; nullOr path;
+      default = null;
+      example = "/root/bitwarden_rs.env";
+      description = ''
+        Additional environment file as defined in <citerefentry>
+        <refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum>
+        </citerefentry>.
+
+        Secrets like <envar>ADMIN_TOKEN</envar> and <envar>SMTP_PASSWORD</envar>
+        may be passed to the service without adding them to the world-readable Nix store.
+
+        Note that this file needs to be available on the host on which
+        <literal>bitwarden_rs</literal> is running.
+      '';
+    };
   };
 
   config = mkIf cfg.enable {
@@ -101,7 +118,7 @@ in {
       serviceConfig = {
         User = user;
         Group = group;
-        EnvironmentFile = configFile;
+        EnvironmentFile = [ configFile ] ++ optional (cfg.environmentFile != null) cfg.environmentFile;
         ExecStart = "${bitwarden_rs}/bin/bitwarden_rs";
         LimitNOFILE = "1048576";
         LimitNPROC = "64";
diff --git a/nixos/modules/services/security/haveged.nix b/nixos/modules/services/security/haveged.nix
index eca5291888100..22ece1883446a 100644
--- a/nixos/modules/services/security/haveged.nix
+++ b/nixos/modules/services/security/haveged.nix
@@ -21,11 +21,11 @@ in
         type = types.bool;
         default = false;
         description = ''
-          Whether to enable to haveged entropy daemon, which refills 
+          Whether to enable to haveged entropy daemon, which refills
           /dev/random when low.
         '';
       };
-      
+
       refill_threshold = mkOption {
         type = types.int;
         default = 1024;
@@ -34,16 +34,16 @@ in
           haveged should refill the entropy pool.
         '';
       };
-      
+
     };
-    
+
   };
-  
-  
+
+
   ###### implementation
-  
+
   config = mkIf cfg.enable {
-  
+
     systemd.services.haveged =
       { description = "Entropy Harvesting Daemon";
         unitConfig.Documentation = "man:haveged(8)";
@@ -63,5 +63,5 @@ in
       };
 
   };
-  
+
 }
diff --git a/nixos/modules/services/security/nginx-sso.nix b/nixos/modules/services/security/nginx-sso.nix
index d792f90abe64b..50d250fc4d761 100644
--- a/nixos/modules/services/security/nginx-sso.nix
+++ b/nixos/modules/services/security/nginx-sso.nix
@@ -4,12 +4,21 @@ with lib;
 
 let
   cfg = config.services.nginx.sso;
-  pkg = getBin pkgs.nginx-sso;
+  pkg = getBin cfg.package;
   configYml = pkgs.writeText "nginx-sso.yml" (builtins.toJSON cfg.configuration);
 in {
   options.services.nginx.sso = {
     enable = mkEnableOption "nginx-sso service";
 
+    package = mkOption {
+      type = types.package;
+      default = pkgs.nginx-sso;
+      defaultText = "pkgs.nginx-sso";
+      description = ''
+        The nginx-sso package that should be used.
+      '';
+    };
+
     configuration = mkOption {
       type = types.attrsOf types.unspecified;
       default = {};
diff --git a/nixos/modules/services/security/oauth2_proxy.nix b/nixos/modules/services/security/oauth2_proxy.nix
index d5c5437329ead..2f9e94bd77bac 100644
--- a/nixos/modules/services/security/oauth2_proxy.nix
+++ b/nixos/modules/services/security/oauth2_proxy.nix
@@ -99,7 +99,7 @@ in
 
     ##############################################
     # PROVIDER configuration
-    # Taken from: https://github.com/pusher/oauth2_proxy/blob/master/providers/providers.go
+    # Taken from: https://github.com/oauth2-proxy/oauth2-proxy/blob/master/providers/providers.go
     provider = mkOption {
       type = types.enum [
         "google"
@@ -346,7 +346,9 @@ in
         type = types.nullOr types.str;
         default = null;
         description = ''
-          An optional cookie domain to force cookies to.
+          Optional cookie domains to force cookies to (ie: `.yourcompany.com`).
+          The longest domain matching the request's host will be used (or the shortest
+          cookie domain if there is no match).
         '';
         example = ".yourcompany.com";
       };
@@ -537,7 +539,7 @@ in
     extraConfig = mkOption {
       default = {};
       description = ''
-        Extra config to pass to oauth2_proxy.
+        Extra config to pass to oauth2-proxy.
       '';
     };
 
@@ -545,7 +547,7 @@ in
       type = types.nullOr types.path;
       default = null;
       description = ''
-        oauth2_proxy allows passing sensitive configuration via environment variables.
+        oauth2-proxy allows passing sensitive configuration via environment variables.
         Make a file that contains lines like
         OAUTH2_PROXY_CLIENT_SECRET=asdfasdfasdf.apps.googleuserscontent.com
         and specify the path here.
@@ -577,7 +579,7 @@ in
       serviceConfig = {
         User = "oauth2_proxy";
         Restart = "always";
-        ExecStart = "${cfg.package}/bin/oauth2_proxy ${configString}";
+        ExecStart = "${cfg.package}/bin/oauth2-proxy ${configString}";
         EnvironmentFile = mkIf (cfg.keyFile != null) cfg.keyFile;
       };
     };
diff --git a/nixos/modules/services/security/physlock.nix b/nixos/modules/services/security/physlock.nix
index 690eb70079d86..da5c22a90a095 100644
--- a/nixos/modules/services/security/physlock.nix
+++ b/nixos/modules/services/security/physlock.nix
@@ -52,6 +52,14 @@ in
         '';
       };
 
+      lockMessage = mkOption {
+        type = types.str;
+        default = "";
+        description = ''
+          Message to show on physlock login terminal.
+        '';
+      };
+
       lockOn = {
 
         suspend = mkOption {
@@ -111,7 +119,7 @@ in
                 ++ cfg.lockOn.extraTargets;
         serviceConfig = {
           Type = "forking";
-          ExecStart = "${pkgs.physlock}/bin/physlock -d${optionalString cfg.disableSysRq "s"}";
+          ExecStart = "${pkgs.physlock}/bin/physlock -d${optionalString cfg.disableSysRq "s"}${optionalString (cfg.lockMessage != "") " -p \"${cfg.lockMessage}\""}";
         };
       };
 
diff --git a/nixos/modules/services/security/privacyidea.nix b/nixos/modules/services/security/privacyidea.nix
index d6abfd0e27180..c2988858e56c3 100644
--- a/nixos/modules/services/security/privacyidea.nix
+++ b/nixos/modules/services/security/privacyidea.nix
@@ -234,7 +234,6 @@ in
           ExecStop = "${pkgs.coreutils}/bin/kill -INT $MAINPID";
           NotifyAccess = "main";
           KillSignal = "SIGQUIT";
-          StandardError = "syslog";
         };
       };
 
diff --git a/nixos/modules/services/security/tor.nix b/nixos/modules/services/security/tor.nix
index 18c105b2f5765..38dc378887a83 100644
--- a/nixos/modules/services/security/tor.nix
+++ b/nixos/modules/services/security/tor.nix
@@ -34,8 +34,8 @@ let
     User tor
     DataDirectory ${torDirectory}
     ${optionalString cfg.enableGeoIP ''
-      GeoIPFile ${pkgs.tor.geoip}/share/tor/geoip
-      GeoIPv6File ${pkgs.tor.geoip}/share/tor/geoip6
+      GeoIPFile ${cfg.package.geoip}/share/tor/geoip
+      GeoIPv6File ${cfg.package.geoip}/share/tor/geoip6
     ''}
 
     ${optint "ControlPort" cfg.controlPort}
@@ -123,6 +123,16 @@ in
         '';
       };
 
+      package = mkOption {
+        type = types.package;
+        default = pkgs.tor;
+        defaultText = "pkgs.tor";
+        example = literalExample "pkgs.tor";
+        description = ''
+          Tor package to use
+        '';
+      };
+
       enableGeoIP = mkOption {
         type = types.bool;
         default = true;
@@ -159,7 +169,7 @@ in
           type = types.bool;
           default = false;
           description = ''
-            Wheter to enable Tor control socket. Control socket is created
+            Whether to enable Tor control socket. Control socket is created
             in <literal>${torRunDirectory}/control</literal>
           '';
         };
@@ -597,7 +607,7 @@ in
             ];
           }
         '';
-        type = types.loaOf (types.submodule ({name, ...}: {
+        type = types.attrsOf (types.submodule ({name, ...}: {
           options = {
 
              name = mkOption {
@@ -749,8 +759,8 @@ in
         serviceConfig =
           { Type         = "simple";
             # Translated from the upstream contrib/dist/tor.service.in
-            ExecStartPre = "${pkgs.tor}/bin/tor -f ${torRcFile} --verify-config";
-            ExecStart    = "${pkgs.tor}/bin/tor -f ${torRcFile}";
+            ExecStartPre = "${cfg.package}/bin/tor -f ${torRcFile} --verify-config";
+            ExecStart    = "${cfg.package}/bin/tor -f ${torRcFile}";
             ExecReload   = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
             KillSignal   = "SIGINT";
             TimeoutSec   = 30;
@@ -773,7 +783,7 @@ in
           };
       };
 
-    environment.systemPackages = [ pkgs.tor ];
+    environment.systemPackages = [ cfg.package ];
 
     services.privoxy = mkIf (cfg.client.enable && cfg.client.privoxy.enable) {
       enable = true;
diff --git a/nixos/modules/services/security/usbguard.nix b/nixos/modules/services/security/usbguard.nix
index f4118eb87fc71..16a90da52314e 100644
--- a/nixos/modules/services/security/usbguard.nix
+++ b/nixos/modules/services/security/usbguard.nix
@@ -1,37 +1,39 @@
-{config, lib, pkgs, ... }:
+{ config, lib, pkgs, ... }:
 
 with lib;
-
 let
-
   cfg = config.services.usbguard;
 
   # valid policy options
   policy = (types.enum [ "allow" "block" "reject" "keep" "apply-policy" ]);
 
+  defaultRuleFile = "/var/lib/usbguard/rules.conf";
+
   # decide what file to use for rules
-  ruleFile = if cfg.rules != null then pkgs.writeText "usbguard-rules" cfg.rules else cfg.ruleFile;
+  ruleFile = if cfg.rules != null then pkgs.writeText "usbguard-rules" cfg.rules else defaultRuleFile;
 
   daemonConf = ''
-      # generated by nixos/modules/services/security/usbguard.nix
-      RuleFile=${ruleFile}
-      ImplicitPolicyTarget=${cfg.implictPolicyTarget}
-      PresentDevicePolicy=${cfg.presentDevicePolicy}
-      PresentControllerPolicy=${cfg.presentControllerPolicy}
-      InsertedDevicePolicy=${cfg.insertedDevicePolicy}
-      RestoreControllerDeviceState=${if cfg.restoreControllerDeviceState then "true" else "false"}
-      # this does not seem useful for endusers to change
-      DeviceManagerBackend=uevent
-      IPCAllowedUsers=${concatStringsSep " " cfg.IPCAllowedUsers}
-      IPCAllowedGroups=${concatStringsSep " " cfg.IPCAllowedGroups}
-      IPCAccessControlFiles=${cfg.IPCAccessControlFiles}
-      DeviceRulesWithPort=${if cfg.deviceRulesWithPort then "true" else "false"}
-      AuditFilePath=${cfg.auditFilePath}
-    '';
-
-    daemonConfFile = pkgs.writeText "usbguard-daemon-conf" daemonConf;
-
-in {
+    # generated by nixos/modules/services/security/usbguard.nix
+    RuleFile=${ruleFile}
+    ImplicitPolicyTarget=${cfg.implictPolicyTarget}
+    PresentDevicePolicy=${cfg.presentDevicePolicy}
+    PresentControllerPolicy=${cfg.presentControllerPolicy}
+    InsertedDevicePolicy=${cfg.insertedDevicePolicy}
+    RestoreControllerDeviceState=${if cfg.restoreControllerDeviceState then "true" else "false"}
+    # this does not seem useful for endusers to change
+    DeviceManagerBackend=uevent
+    IPCAllowedUsers=${concatStringsSep " " cfg.IPCAllowedUsers}
+    IPCAllowedGroups=${concatStringsSep " " cfg.IPCAllowedGroups}
+    IPCAccessControlFiles=/var/lib/usbguard/IPCAccessControl.d/
+    DeviceRulesWithPort=${if cfg.deviceRulesWithPort then "true" else "false"}
+    # HACK: that way audit logs still land in the journal
+    AuditFilePath=/dev/null
+  '';
+
+  daemonConfFile = pkgs.writeText "usbguard-daemon-conf" daemonConf;
+
+in
+{
 
   ###### interface
 
@@ -49,22 +51,6 @@ in {
         '';
       };
 
-      ruleFile = mkOption {
-        type = types.path;
-        default = "/var/lib/usbguard/rules.conf";
-        description = ''
-          The USBGuard daemon will use this file to load the policy rule set
-          from it and to write new rules received via the IPC interface.
-
-          Running the command <literal>usbguard generate-policy</literal> as
-          root will generate a config for your currently plugged in devices.
-          For a in depth guide consult the official documentation.
-
-          Setting the <literal>rules</literal> option will ignore the
-          <literal>ruleFile</literal> option.
-        '';
-      };
-
       rules = mkOption {
         type = types.nullOr types.lines;
         default = null;
@@ -72,16 +58,20 @@ in {
           allow with-interface equals { 08:*:* }
         '';
         description = ''
-          The USBGuard daemon will load this policy rule set. Modifying it via
-          the IPC interface won't work if you use this option, since the
-          contents of this option will be written into the nix-store it will be
-          read-only.
+          The USBGuard daemon will load this as the policy rule set.
+          As these rules are NixOS managed they are immutable and can't
+          be changed by the IPC interface.
+
+          If you do not set this option, the USBGuard daemon will load
+          it's policy rule set from <literal>${defaultRuleFile}</literal>.
+          This file can be changed manually or via the IPC interface.
 
-          You can still use <literal> usbguard generate-policy</literal> to
-          generate rules, but you would have to insert them here.
+          Running <literal>usbguard generate-policy</literal> as root will
+          generate a config for your currently plugged in devices.
 
-          Setting the <literal>rules</literal> option will ignore the
-          <literal>ruleFile</literal> option.
+          For more details see <citerefentry>
+          <refentrytitle>usbguard-rules.conf</refentrytitle>
+          <manvolnum>5</manvolnum></citerefentry>.
         '';
       };
 
@@ -155,17 +145,6 @@ in {
         '';
       };
 
-      IPCAccessControlFiles = mkOption {
-        type = types.path;
-        default = "/var/lib/usbguard/IPCAccessControl.d/";
-        description = ''
-          The files at this location will be interpreted by the daemon as IPC
-          access control definition files. See the IPC ACCESS CONTROL section
-          in <citerefentry><refentrytitle>usbguard-daemon.conf</refentrytitle>
-          <manvolnum>5</manvolnum></citerefentry> for more details.
-        '';
-      };
-
       deviceRulesWithPort = mkOption {
         type = types.bool;
         default = false;
@@ -173,14 +152,6 @@ in {
           Generate device specific rules including the "via-port" attribute.
         '';
       };
-
-      auditFilePath = mkOption {
-        type = types.path;
-        default = "/var/log/usbguard/usbguard-audit.log";
-        description = ''
-          USBGuard audit events log file path.
-        '';
-      };
     };
   };
 
@@ -197,17 +168,19 @@ in {
       wantedBy = [ "basic.target" ];
       wants = [ "systemd-udevd.service" ];
 
-      # make sure an empty rule file and required directories exist
-      preStart = ''
-        mkdir -p $(dirname "${cfg.ruleFile}") $(dirname "${cfg.auditFilePath}") "${cfg.IPCAccessControlFiles}" \
-          && ([ -f "${cfg.ruleFile}" ] || touch ${cfg.ruleFile})
-      '';
+      # make sure an empty rule file exists
+      preStart = ''[ -f "${ruleFile}" ] || touch ${ruleFile}'';
 
       serviceConfig = {
         Type = "simple";
         ExecStart = ''${cfg.package}/bin/usbguard-daemon -P -k -c ${daemonConfFile}'';
         Restart = "on-failure";
 
+        StateDirectory = [
+          "usbguard"
+          "usbguard/IPCAccessControl.d"
+        ];
+
         AmbientCapabilities = "";
         CapabilityBoundingSet = "CAP_CHOWN CAP_FOWNER";
         DeviceAllow = "/dev/null rw";
@@ -223,8 +196,8 @@ in {
         ProtectKernelModules = true;
         ProtectSystem = true;
         ReadOnlyPaths = "-/";
-        ReadWritePaths = "-/dev/shm -${dirOf cfg.auditFilePath} -/tmp -${dirOf cfg.ruleFile}";
-        RestrictAddressFamilies = "AF_UNIX AF_NETLINK";
+        ReadWritePaths = "-/dev/shm -/tmp";
+        RestrictAddressFamilies = [ "AF_UNIX" "AF_NETLINK" ];
         RestrictNamespaces = true;
         RestrictRealtime = true;
         SystemCallArchitectures = "native";
@@ -233,4 +206,9 @@ in {
       };
     };
   };
+  imports = [
+    (mkRemovedOptionModule [ "services" "usbguard" "ruleFile" ] "The usbguard module now uses ${defaultRuleFile} as ruleFile. Alternatively, use services.usbguard.rules to configure rules.")
+    (mkRemovedOptionModule [ "services" "usbguard" "IPCAccessControlFiles" ] "The usbguard module now hardcodes IPCAccessControlFiles to /var/lib/usbguard/IPCAccessControl.d.")
+    (mkRemovedOptionModule [ "services" "usbguard" "auditFilePath" ] "Removed usbguard module audit log files. Audit logs can be found in the systemd journal.")
+  ];
 }
diff --git a/nixos/modules/services/security/yubikey-agent.nix b/nixos/modules/services/security/yubikey-agent.nix
new file mode 100644
index 0000000000000..2972c64a36413
--- /dev/null
+++ b/nixos/modules/services/security/yubikey-agent.nix
@@ -0,0 +1,60 @@
+# Global configuration for yubikey-agent.
+
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.yubikey-agent;
+
+  # reuse the pinentryFlavor option from the gnupg module
+  pinentryFlavor = config.programs.gnupg.agent.pinentryFlavor;
+in
+{
+  ###### interface
+
+  meta.maintainers = with maintainers; [ philandstuff rawkode ];
+
+  options = {
+
+    services.yubikey-agent = {
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to start yubikey-agent when you log in.  Also sets
+          SSH_AUTH_SOCK to point at yubikey-agent.
+
+          Note that yubikey-agent will use whatever pinentry is
+          specified in programs.gnupg.agent.pinentryFlavor.
+        '';
+      };
+
+      package = mkOption {
+        type = types.package;
+        default = pkgs.yubikey-agent;
+        defaultText = "pkgs.yubikey-agent";
+        description = ''
+          The package used for the yubikey-agent daemon.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = [ cfg.package ];
+    systemd.packages = [ cfg.package ];
+
+    # This overrides the systemd user unit shipped with the
+    # yubikey-agent package
+    systemd.user.services.yubikey-agent = mkIf (pinentryFlavor != null) {
+      path = [ pkgs.pinentry.${pinentryFlavor} ];
+    };
+
+    environment.extraInit = ''
+      if [ -z "$SSH_AUTH_SOCK" -a -n "$XDG_RUNTIME_DIR" ]; then
+        export SSH_AUTH_SOCK="$XDG_RUNTIME_DIR/yubikey-agent/yubikey-agent.sock"
+      fi
+    '';
+  };
+}
diff --git a/nixos/modules/services/system/earlyoom.nix b/nixos/modules/services/system/earlyoom.nix
index c6a001d30eeb3..e29bdbe264cc8 100644
--- a/nixos/modules/services/system/earlyoom.nix
+++ b/nixos/modules/services/system/earlyoom.nix
@@ -106,7 +106,6 @@ in
       path = optional ecfg.enableNotifications pkgs.dbus;
       serviceConfig = {
         StandardOutput = "null";
-        StandardError = "syslog";
         ExecStart = ''
           ${pkgs.earlyoom}/bin/earlyoom \
           -m ${toString ecfg.freeMemThreshold} \
diff --git a/nixos/modules/services/torrent/transmission.nix b/nixos/modules/services/torrent/transmission.nix
index 1bfcf2de82f84..014a22bb5a8d6 100644
--- a/nixos/modules/services/torrent/transmission.nix
+++ b/nixos/modules/services/torrent/transmission.nix
@@ -1,52 +1,54 @@
-{ config, lib, pkgs, ... }:
+{ config, lib, pkgs, options, ... }:
 
 with lib;
 
 let
   cfg = config.services.transmission;
+  inherit (config.environment) etc;
   apparmor = config.security.apparmor.enable;
-
-  homeDir = cfg.home;
-  downloadDirPermissions = cfg.downloadDirPermissions;
-  downloadDir = "${homeDir}/Downloads";
-  incompleteDir = "${homeDir}/.incomplete";
-
-  settingsDir = "${homeDir}/config";
-  settingsFile = pkgs.writeText "settings.json" (builtins.toJSON fullSettings);
-
-  # for users in group "transmission" to have access to torrents
-  fullSettings = { umask = 2; download-dir = downloadDir; incomplete-dir = incompleteDir; } // cfg.settings;
-
-  preStart = pkgs.writeScript "transmission-pre-start" ''
-    #!${pkgs.runtimeShell}
-    set -ex
-    cp -f ${settingsFile} ${settingsDir}/settings.json
-  '';
+  rootDir = "/run/transmission";
+  homeDir = "/var/lib/transmission";
+  settingsDir = ".config/transmission-daemon";
+  downloadsDir = "Downloads";
+  incompleteDir = ".incomplete";
+  watchDir = "watchdir";
+  # TODO: switch to configGen.json once RFC0042 is implemented
+  settingsFile = pkgs.writeText "settings.json" (builtins.toJSON cfg.settings);
 in
 {
   options = {
     services.transmission = {
-      enable = mkOption {
-        type = types.bool;
-        default = false;
-        description = ''
-          Whether or not to enable the headless Transmission BitTorrent daemon.
+      enable = mkEnableOption ''the headless Transmission BitTorrent daemon.
 
-          Transmission daemon can be controlled via the RPC interface using
-          transmission-remote or the WebUI (http://localhost:9091/ by default).
+        Transmission daemon can be controlled via the RPC interface using
+        transmission-remote, the WebUI (http://127.0.0.1:9091/ by default),
+        or other clients like stig or tremc.
 
-          Torrents are downloaded to ${downloadDir} by default and are
-          accessible to users in the "transmission" group.
-        '';
-      };
+        Torrents are downloaded to ${homeDir}/${downloadsDir} by default and are
+        accessible to users in the "transmission" group'';
 
-      settings = mkOption {
+      settings = mkOption rec {
+        # TODO: switch to types.config.json as prescribed by RFC0042 once it's implemented
         type = types.attrs;
+        apply = recursiveUpdate default;
         default =
           {
-            download-dir = downloadDir;
-            incomplete-dir = incompleteDir;
+            download-dir = "${cfg.home}/${downloadsDir}";
+            incomplete-dir = "${cfg.home}/${incompleteDir}";
             incomplete-dir-enabled = true;
+            watch-dir = "${cfg.home}/${watchDir}";
+            watch-dir-enabled = false;
+            message-level = 1;
+            peer-port = 51413;
+            peer-port-random-high = 65535;
+            peer-port-random-low = 49152;
+            peer-port-random-on-start = false;
+            rpc-bind-address = "127.0.0.1";
+            rpc-port = 9091;
+            script-torrent-done-enabled = false;
+            script-torrent-done-filename = "";
+            umask = 2; # 0o002 in decimal as expected by Transmission
+            utp-enabled = true;
           };
         example =
           {
@@ -56,11 +58,12 @@ in
             rpc-whitelist = "127.0.0.1,192.168.*.*";
           };
         description = ''
-          Attribute set whos fields overwrites fields in settings.json (each
-          time the service starts). String values must be quoted, integer and
+          Attribute set whose fields overwrites fields in
+          <literal>.config/transmission-daemon/settings.json</literal>
+          (each time the service starts). String values must be quoted, integer and
           boolean values must not.
 
-          See https://github.com/transmission/transmission/wiki/Editing-Configuration-Files
+          See <link xlink:href="https://github.com/transmission/transmission/wiki/Editing-Configuration-Files">Transmission's Wiki</link>
           for documentation.
         '';
       };
@@ -70,22 +73,32 @@ in
         default = "770";
         example = "775";
         description = ''
-          The permissions to set for download-dir and incomplete-dir.
-          They will be applied on every service start.
+          The permissions set by <literal>systemd.activationScripts.transmission-daemon</literal>
+          on the directories <link linkend="opt-services.transmission.settings">settings.download-dir</link>
+          and <link linkend="opt-services.transmission.settings">settings.incomplete-dir</link>.
+          Note that you may also want to change
+          <link linkend="opt-services.transmission.settings">settings.umask</link>.
         '';
       };
 
       port = mkOption {
-        type = types.int;
-        default = 9091;
-        description = "TCP port number to run the RPC/web interface.";
+        type = types.port;
+        description = ''
+          TCP port number to run the RPC/web interface.
+
+          If instead you want to change the peer port,
+          use <link linkend="opt-services.transmission.settings">settings.peer-port</link>
+          or <link linkend="opt-services.transmission.settings">settings.peer-port-random-on-start</link>.
+        '';
       };
 
       home = mkOption {
         type = types.path;
-        default = "/var/lib/transmission";
+        default = homeDir;
         description = ''
-          The directory where transmission will create files.
+          The directory where Transmission will create <literal>${settingsDir}</literal>.
+          as well as <literal>${downloadsDir}/</literal> unless <link linkend="opt-services.transmission.settings">settings.download-dir</link> is changed,
+          and <literal>${incompleteDir}/</literal> unless <link linkend="opt-services.transmission.settings">settings.incomplete-dir</link> is changed.
         '';
       };
 
@@ -100,32 +113,179 @@ in
         default = "transmission";
         description = "Group account under which Transmission runs.";
       };
+
+      credentialsFile = mkOption {
+        type = types.path;
+        description = ''
+          Path to a JSON file to be merged with the settings.
+          Useful to merge a file which is better kept out of the Nix store
+          because it contains sensible data like <link linkend="opt-services.transmission.settings">settings.rpc-password</link>.
+        '';
+        default = "/dev/null";
+        example = "/var/lib/secrets/transmission/settings.json";
+      };
+
+      openFirewall = mkEnableOption "opening of the peer port(s) in the firewall";
+
+      performanceNetParameters = mkEnableOption ''tweaking of kernel parameters
+        to open many more connections at the same time.
+
+        Note that you may also want to increase
+        <link linkend="opt-services.transmission.settings">settings.peer-limit-global</link>.
+        And be aware that these settings are quite aggressive
+        and might not suite your regular desktop use.
+        For instance, SSH sessions may time out more easily'';
     };
   };
 
   config = mkIf cfg.enable {
-    systemd.tmpfiles.rules = [
-      "d '${homeDir}' 0770 '${cfg.user}' '${cfg.group}' - -"
-      "d '${settingsDir}' 0700 '${cfg.user}' '${cfg.group}' - -"
-      "d '${fullSettings.download-dir}' '${downloadDirPermissions}' '${cfg.user}' '${cfg.group}' - -"
-      "d '${fullSettings.incomplete-dir}' '${downloadDirPermissions}' '${cfg.user}' '${cfg.group}' - -"
+    # Note that using systemd.tmpfiles would not work here
+    # because it would fail when creating a directory
+    # with a different owner than its parent directory, by saying:
+    # Detected unsafe path transition /home/foo → /home/foo/Downloads during canonicalization of /home/foo/Downloads
+    # when /home/foo is not owned by cfg.user.
+    # Note also that using an ExecStartPre= wouldn't work either
+    # because BindPaths= needs these directories before.
+    system.activationScripts.transmission-daemon = ''
+      install -d -m 700 '${cfg.home}/${settingsDir}'
+      chown -R '${cfg.user}:${cfg.group}' ${cfg.home}/${settingsDir}
+      install -d -m '${cfg.downloadDirPermissions}' -o '${cfg.user}' -g '${cfg.group}' '${cfg.settings.download-dir}'
+      '' + optionalString cfg.settings.incomplete-dir-enabled ''
+      install -d -m '${cfg.downloadDirPermissions}' -o '${cfg.user}' -g '${cfg.group}' '${cfg.settings.incomplete-dir}'
+      '';
+
+    assertions = [
+      { assertion = builtins.match "^/.*" cfg.home != null;
+        message = "`services.transmission.home' must be an absolute path.";
+      }
+      { assertion = types.path.check cfg.settings.download-dir;
+        message = "`services.transmission.settings.download-dir' must be an absolute path.";
+      }
+      { assertion = types.path.check cfg.settings.incomplete-dir;
+        message = "`services.transmission.settings.incomplete-dir' must be an absolute path.";
+      }
+      { assertion = types.path.check cfg.settings.watch-dir;
+        message = "`services.transmission.settings.watch-dir' must be an absolute path.";
+      }
+      { assertion = cfg.settings.script-torrent-done-filename == "" || types.path.check cfg.settings.script-torrent-done-filename;
+        message = "`services.transmission.settings.script-torrent-done-filename' must be an absolute path.";
+      }
+      { assertion = types.port.check cfg.settings.rpc-port;
+        message = "${toString cfg.settings.rpc-port} is not a valid port number for `services.transmission.settings.rpc-port`.";
+      }
+      # In case both port and settings.rpc-port are explicitely defined: they must be the same.
+      { assertion = !options.services.transmission.port.isDefined || cfg.port == cfg.settings.rpc-port;
+        message = "`services.transmission.port' is not equal to `services.transmission.settings.rpc-port'";
+      }
     ];
 
+    services.transmission.settings =
+      optionalAttrs options.services.transmission.port.isDefined { rpc-port = cfg.port; };
+
     systemd.services.transmission = {
       description = "Transmission BitTorrent Service";
       after = [ "network.target" ] ++ optional apparmor "apparmor.service";
-      requires = mkIf apparmor [ "apparmor.service" ];
+      requires = optional apparmor "apparmor.service";
       wantedBy = [ "multi-user.target" ];
+      environment.CURL_CA_BUNDLE = etc."ssl/certs/ca-certificates.crt".source;
 
-      # 1) Only the "transmission" user and group have access to torrents.
-      # 2) Optionally update/force specific fields into the configuration file.
-      serviceConfig.ExecStartPre = preStart;
-      serviceConfig.ExecStart = "${pkgs.transmission}/bin/transmission-daemon -f --port ${toString config.services.transmission.port} --config-dir ${settingsDir}";
-      serviceConfig.ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
-      serviceConfig.User = cfg.user;
-      serviceConfig.Group = cfg.group;
-      # NOTE: transmission has an internal umask that also must be set (in settings.json)
-      serviceConfig.UMask = "0002";
+      serviceConfig = {
+        # Use "+" because credentialsFile may not be accessible to User= or Group=.
+        ExecStartPre = [("+" + pkgs.writeShellScript "transmission-prestart" ''
+          set -eu${lib.optionalString (cfg.settings.message-level >= 3) "x"}
+          ${pkgs.jq}/bin/jq --slurp add ${settingsFile} '${cfg.credentialsFile}' |
+          install -D -m 600 -o '${cfg.user}' -g '${cfg.group}' /dev/stdin \
+           '${cfg.home}/${settingsDir}/settings.json'
+        '')];
+        ExecStart="${pkgs.transmission}/bin/transmission-daemon -f";
+        ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
+        User = cfg.user;
+        Group = cfg.group;
+        # Create rootDir in the host's mount namespace.
+        RuntimeDirectory = [(baseNameOf rootDir)];
+        RuntimeDirectoryMode = "755";
+        # Avoid mounting rootDir in the own rootDir of ExecStart='s mount namespace.
+        InaccessiblePaths = ["-+${rootDir}"];
+        # This is for BindPaths= and BindReadOnlyPaths=
+        # to allow traversal of directories they create in RootDirectory=.
+        UMask = "0066";
+        # Using RootDirectory= makes it possible
+        # to use the same paths download-dir/incomplete-dir
+        # (which appear in user's interfaces) without requiring cfg.user
+        # to have access to their parent directories,
+        # by using BindPaths=/BindReadOnlyPaths=.
+        # Note that TemporaryFileSystem= could have been used instead
+        # but not without adding some BindPaths=/BindReadOnlyPaths=
+        # that would only be needed for ExecStartPre=,
+        # because RootDirectoryStartOnly=true would not help.
+        RootDirectory = rootDir;
+        RootDirectoryStartOnly = true;
+        MountAPIVFS = true;
+        BindPaths =
+          [ "${cfg.home}/${settingsDir}"
+            cfg.settings.download-dir
+          ] ++
+          optional cfg.settings.incomplete-dir-enabled
+            cfg.settings.incomplete-dir
+          ++
+          optional cfg.settings.watch-dir-enabled
+            cfg.settings.watch-dir
+          ;
+        BindReadOnlyPaths = [
+          # No confinement done of /nix/store here like in systemd-confinement.nix,
+          # an AppArmor profile is provided to get a confinement based upon paths and rights.
+          builtins.storeDir
+          "/etc"
+          ] ++
+          optional (cfg.settings.script-torrent-done-enabled &&
+                    cfg.settings.script-torrent-done-filename != "")
+            cfg.settings.script-torrent-done-filename;
+        # The following options are only for optimizing:
+        # systemd-analyze security transmission
+        AmbientCapabilities = "";
+        CapabilityBoundingSet = "";
+        # ProtectClock= adds DeviceAllow=char-rtc r
+        DeviceAllow = "";
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        NoNewPrivileges = true;
+        PrivateDevices = true;
+        PrivateMounts = true;
+        PrivateNetwork = mkDefault false;
+        PrivateTmp = true;
+        PrivateUsers = true;
+        ProtectClock = true;
+        ProtectControlGroups = true;
+        # ProtectHome=true would not allow BindPaths= to work accross /home,
+        # and ProtectHome=tmpfs would break statfs(),
+        # preventing transmission-daemon to report the available free space.
+        # However, RootDirectory= is used, so this is not a security concern
+        # since there would be nothing in /home but any BindPaths= wanted by the user.
+        ProtectHome = "read-only";
+        ProtectHostname = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectSystem = "strict";
+        RemoveIPC = true;
+        # AF_UNIX may become usable one day:
+        # https://github.com/transmission/transmission/issues/441
+        RestrictAddressFamilies = [ "AF_UNIX" "AF_INET" "AF_INET6" ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+        SystemCallFilter = [
+          "@system-service"
+          # Groups in @system-service which do not contain a syscall
+          # listed by perf stat -e 'syscalls:sys_enter_*' transmission-daemon -f
+          # in tests, and seem likely not necessary for transmission-daemon.
+          "~@aio" "~@chown" "~@keyring" "~@memlock" "~@resources" "~@setuid" "~@timer"
+          # In the @privileged group, but reached when querying infos through RPC (eg. with stig).
+          "quotactl"
+        ];
+        SystemCallArchitectures = "native";
+        SystemCallErrorNumber = "EPERM";
+      };
     };
 
     # It's useful to have transmission in path, e.g. for remote control
@@ -133,70 +293,159 @@ in
 
     users.users = optionalAttrs (cfg.user == "transmission") ({
       transmission = {
-        name = "transmission";
         group = cfg.group;
         uid = config.ids.uids.transmission;
         description = "Transmission BitTorrent user";
-        home = homeDir;
-        createHome = true;
+        home = cfg.home;
       };
     });
 
     users.groups = optionalAttrs (cfg.group == "transmission") ({
       transmission = {
-        name = "transmission";
         gid = config.ids.gids.transmission;
       };
     });
 
-    # AppArmor profile
+    networking.firewall = mkIf cfg.openFirewall (
+      if cfg.settings.peer-port-random-on-start
+      then
+        { allowedTCPPortRanges =
+            [ { from = cfg.settings.peer-port-random-low;
+                to   = cfg.settings.peer-port-random-high;
+              }
+            ];
+          allowedUDPPortRanges =
+            [ { from = cfg.settings.peer-port-random-low;
+                to   = cfg.settings.peer-port-random-high;
+              }
+            ];
+        }
+      else
+        { allowedTCPPorts = [ cfg.settings.peer-port ];
+          allowedUDPPorts = [ cfg.settings.peer-port ];
+        }
+    );
+
+    boot.kernel.sysctl = mkMerge [
+      # Transmission uses a single UDP socket in order to implement multiple uTP sockets,
+      # and thus expects large kernel buffers for the UDP socket,
+      # https://trac.transmissionbt.com/browser/trunk/libtransmission/tr-udp.c?rev=11956.
+      # at least up to the values hardcoded here:
+      (mkIf cfg.settings.utp-enabled {
+        "net.core.rmem_max" = mkDefault "4194304"; # 4MB
+        "net.core.wmem_max" = mkDefault "1048576"; # 1MB
+      })
+      (mkIf cfg.performanceNetParameters {
+        # Increase the number of available source (local) TCP and UDP ports to 49151.
+        # Usual default is 32768 60999, ie. 28231 ports.
+        # Find out your current usage with: ss -s
+        "net.ipv4.ip_local_port_range" = "16384 65535";
+        # Timeout faster generic TCP states.
+        # Usual default is 600.
+        # Find out your current usage with: watch -n 1 netstat -nptuo
+        "net.netfilter.nf_conntrack_generic_timeout" = 60;
+        # Timeout faster established but inactive connections.
+        # Usual default is 432000.
+        "net.netfilter.nf_conntrack_tcp_timeout_established" = 600;
+        # Clear immediately TCP states after timeout.
+        # Usual default is 120.
+        "net.netfilter.nf_conntrack_tcp_timeout_time_wait" = 1;
+        # Increase the number of trackable connections.
+        # Usual default is 262144.
+        # Find out your current usage with: conntrack -C
+        "net.netfilter.nf_conntrack_max" = 1048576;
+      })
+    ];
+
     security.apparmor.profiles = mkIf apparmor [
       (pkgs.writeText "apparmor-transmission-daemon" ''
-        #include <tunables/global>
+        include <tunables/global>
 
         ${pkgs.transmission}/bin/transmission-daemon {
-          #include <abstractions/base>
-          #include <abstractions/nameservice>
-
-          ${getLib pkgs.glibc}/lib/*.so                    mr,
-          ${getLib pkgs.libevent}/lib/libevent*.so*        mr,
-          ${getLib pkgs.curl}/lib/libcurl*.so*             mr,
-          ${getLib pkgs.openssl}/lib/libssl*.so*           mr,
-          ${getLib pkgs.openssl}/lib/libcrypto*.so*        mr,
-          ${getLib pkgs.zlib}/lib/libz*.so*                mr,
-          ${getLib pkgs.libssh2}/lib/libssh2*.so*          mr,
-          ${getLib pkgs.systemd}/lib/libsystemd*.so*       mr,
-          ${getLib pkgs.xz}/lib/liblzma*.so*               mr,
-          ${getLib pkgs.libgcrypt}/lib/libgcrypt*.so*      mr,
-          ${getLib pkgs.libgpgerror}/lib/libgpg-error*.so* mr,
-          ${getLib pkgs.nghttp2}/lib/libnghttp2*.so*       mr,
-          ${getLib pkgs.c-ares}/lib/libcares*.so*          mr,
-          ${getLib pkgs.libcap}/lib/libcap*.so*            mr,
-          ${getLib pkgs.attr}/lib/libattr*.so*             mr,
-          ${getLib pkgs.lz4}/lib/liblz4*.so*               mr,
-          ${getLib pkgs.libkrb5}/lib/lib*.so*              mr,
-          ${getLib pkgs.keyutils}/lib/libkeyutils*.so*     mr,
-          ${getLib pkgs.utillinuxMinimal.out}/lib/libblkid.so.* mr,
-          ${getLib pkgs.utillinuxMinimal.out}/lib/libmount.so.* mr,
-          ${getLib pkgs.utillinuxMinimal.out}/lib/libuuid.so.* mr,
-          ${getLib pkgs.gcc.cc.lib}/lib/libstdc++.so.* mr,
-          ${getLib pkgs.gcc.cc.lib}/lib/libgcc_s.so.* mr,
-
-          @{PROC}/sys/kernel/random/uuid   r,
-          @{PROC}/sys/vm/overcommit_memory r,
-
-          ${pkgs.openssl.out}/etc/**                     r,
-          ${pkgs.transmission}/share/transmission/** r,
-
-          owner ${settingsDir}/** rw,
-
-          ${fullSettings.download-dir}/** rw,
-          ${optionalString fullSettings.incomplete-dir-enabled ''
-            ${fullSettings.incomplete-dir}/** rw,
+          include <abstractions/base>
+          include <abstractions/nameservice>
+
+          # NOTE: https://github.com/NixOS/nixpkgs/pull/93457
+          # will remove the need for these by fixing <abstractions/base>
+          r ${etc."hosts".source},
+          r /etc/ld-nix.so.preload,
+          ${lib.optionalString (builtins.hasAttr "ld-nix.so.preload" etc) ''
+            r ${etc."ld-nix.so.preload".source},
+            ${concatMapStrings (p: optionalString (p != "") ("mr ${p},\n"))
+              (splitString "\n" config.environment.etc."ld-nix.so.preload".text)}
           ''}
+          r ${etc."ssl/certs/ca-certificates.crt".source},
+          r ${pkgs.tzdata}/share/zoneinfo/**,
+          r ${pkgs.stdenv.cc.libc}/share/i18n/**,
+          r ${pkgs.stdenv.cc.libc}/share/locale/**,
+
+          mr ${getLib pkgs.stdenv.cc.cc}/lib/*.so*,
+          mr ${getLib pkgs.stdenv.cc.libc}/lib/*.so*,
+          mr ${getLib pkgs.attr}/lib/libattr*.so*,
+          mr ${getLib pkgs.c-ares}/lib/libcares*.so*,
+          mr ${getLib pkgs.curl}/lib/libcurl*.so*,
+          mr ${getLib pkgs.keyutils}/lib/libkeyutils*.so*,
+          mr ${getLib pkgs.libcap}/lib/libcap*.so*,
+          mr ${getLib pkgs.libevent}/lib/libevent*.so*,
+          mr ${getLib pkgs.libgcrypt}/lib/libgcrypt*.so*,
+          mr ${getLib pkgs.libgpgerror}/lib/libgpg-error*.so*,
+          mr ${getLib pkgs.libkrb5}/lib/lib*.so*,
+          mr ${getLib pkgs.libssh2}/lib/libssh2*.so*,
+          mr ${getLib pkgs.lz4}/lib/liblz4*.so*,
+          mr ${getLib pkgs.nghttp2}/lib/libnghttp2*.so*,
+          mr ${getLib pkgs.openssl}/lib/libcrypto*.so*,
+          mr ${getLib pkgs.openssl}/lib/libssl*.so*,
+          mr ${getLib pkgs.systemd}/lib/libsystemd*.so*,
+          mr ${getLib pkgs.utillinuxMinimal.out}/lib/libblkid.so*,
+          mr ${getLib pkgs.utillinuxMinimal.out}/lib/libmount.so*,
+          mr ${getLib pkgs.utillinuxMinimal.out}/lib/libuuid.so*,
+          mr ${getLib pkgs.xz}/lib/liblzma*.so*,
+          mr ${getLib pkgs.zlib}/lib/libz*.so*,
+
+          r @{PROC}/sys/kernel/random/uuid,
+          r @{PROC}/sys/vm/overcommit_memory,
+          # @{pid} is not a kernel variable yet but a regexp
+          #r @{PROC}/@{pid}/environ,
+          r @{PROC}/@{pid}/mounts,
+          rwk /tmp/tr_session_id_*,
+
+          r ${pkgs.openssl.out}/etc/**,
+          r ${config.systemd.services.transmission.environment.CURL_CA_BUNDLE},
+          r ${pkgs.transmission}/share/transmission/**,
+
+          owner rw ${cfg.home}/${settingsDir}/**,
+          rw ${cfg.settings.download-dir}/**,
+          ${optionalString cfg.settings.incomplete-dir-enabled ''
+            rw ${cfg.settings.incomplete-dir}/**,
+          ''}
+          ${optionalString cfg.settings.watch-dir-enabled ''
+            rw ${cfg.settings.watch-dir}/**,
+          ''}
+          profile dirs {
+            rw ${cfg.settings.download-dir}/**,
+            ${optionalString cfg.settings.incomplete-dir-enabled ''
+              rw ${cfg.settings.incomplete-dir}/**,
+            ''}
+            ${optionalString cfg.settings.watch-dir-enabled ''
+              rw ${cfg.settings.watch-dir}/**,
+            ''}
+          }
+
+          ${optionalString (cfg.settings.script-torrent-done-enabled &&
+                            cfg.settings.script-torrent-done-filename != "") ''
+            # Stack transmission_directories profile on top of
+            # any existing profile for script-torrent-done-filename
+            # FIXME: to be tested as I'm not sure it works well with NoNewPrivileges=
+            # https://gitlab.com/apparmor/apparmor/-/wikis/AppArmorStacking#seccomp-and-no_new_privs
+            px ${cfg.settings.script-torrent-done-filename} -> &@{dirs},
+          ''}
+
+          # FIXME: enable customizing using https://github.com/NixOS/nixpkgs/pull/93457
+          # include <local/transmission-daemon>
         }
       '')
     ];
   };
 
+  meta.maintainers = with lib.maintainers; [ julm ];
 }
diff --git a/nixos/modules/services/video/epgstation/default.nix b/nixos/modules/services/video/epgstation/default.nix
new file mode 100644
index 0000000000000..8d6d431fa55aa
--- /dev/null
+++ b/nixos/modules/services/video/epgstation/default.nix
@@ -0,0 +1,295 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.epgstation;
+
+  username = config.users.users.epgstation.name;
+  groupname = config.users.users.epgstation.group;
+
+  settingsFmt = pkgs.formats.json {};
+  settingsTemplate = settingsFmt.generate "config.json" cfg.settings;
+  preStartScript = pkgs.writeScript "epgstation-prestart" ''
+    #!${pkgs.runtimeShell}
+
+    PASSWORD="$(head -n1 "${cfg.basicAuth.passwordFile}")"
+    DB_PASSWORD="$(head -n1 "${cfg.database.passwordFile}")"
+
+    # setup configuration
+    touch /etc/epgstation/config.json
+    chmod 640 /etc/epgstation/config.json
+    sed \
+      -e "s,@password@,$PASSWORD,g" \
+      -e "s,@dbPassword@,$DB_PASSWORD,g" \
+      ${settingsTemplate} > /etc/epgstation/config.json
+    chown "${username}:${groupname}" /etc/epgstation/config.json
+
+    # NOTE: Use password authentication, since mysqljs does not yet support auth_socket
+    if [ ! -e /var/lib/epgstation/db-created ]; then
+      ${pkgs.mysql}/bin/mysql -e \
+        "GRANT ALL ON \`${cfg.database.name}\`.* TO '${username}'@'localhost' IDENTIFIED by '$DB_PASSWORD';"
+      touch /var/lib/epgstation/db-created
+    fi
+  '';
+
+  streamingConfig = builtins.fromJSON (builtins.readFile ./streaming.json);
+  logConfig = {
+    appenders.stdout.type = "stdout";
+    categories = {
+      default = { appenders = [ "stdout" ]; level = "info"; };
+      system = { appenders = [ "stdout" ]; level = "info"; };
+      access = { appenders = [ "stdout" ]; level = "info"; };
+      stream = { appenders = [ "stdout" ]; level = "info"; };
+    };
+  };
+
+  defaultPassword = "INSECURE_GO_CHECK_CONFIGURATION_NIX\n";
+in
+{
+  options.services.epgstation = {
+    enable = mkEnableOption pkgs.epgstation.meta.description;
+
+    usePreconfiguredStreaming = mkOption {
+      type = types.bool;
+      default = true;
+      description = ''
+        Use preconfigured default streaming options.
+
+        Upstream defaults:
+        <link xlink:href="https://github.com/l3tnun/EPGStation/blob/master/config/config.sample.json"/>
+      '';
+    };
+
+    port = mkOption {
+      type = types.port;
+      default = 20772;
+      description = ''
+        HTTP port for EPGStation to listen on.
+      '';
+    };
+
+    socketioPort = mkOption {
+      type = types.port;
+      default = cfg.port + 1;
+      description = ''
+        Socket.io port for EPGStation to listen on.
+      '';
+    };
+
+    clientSocketioPort = mkOption {
+      type = types.port;
+      default = cfg.socketioPort;
+      description = ''
+        Socket.io port that the web client is going to connect to. This may be
+        different from <option>socketioPort</option> if EPGStation is hidden
+        behind a reverse proxy.
+      '';
+    };
+
+    openFirewall = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Open ports in the firewall for the EPGStation web interface.
+
+        <warning>
+          <para>
+            Exposing EPGStation to the open internet is generally advised
+            against. Only use it inside a trusted local network, or consider
+            putting it behind a VPN if you want remote access.
+          </para>
+        </warning>
+      '';
+    };
+
+    basicAuth = {
+      user = mkOption {
+        type = with types; nullOr str;
+        default = null;
+        example = "epgstation";
+        description = ''
+          Basic auth username for EPGStation. If <literal>null</literal>, basic
+          auth will be disabled.
+
+          <warning>
+            <para>
+              Basic authentication has known weaknesses, the most critical being
+              that it sends passwords over the network in clear text. Use this
+              feature to control access to EPGStation within your family and
+              friends, but don't rely on it for security.
+            </para>
+          </warning>
+        '';
+      };
+
+      passwordFile = mkOption {
+        type = types.path;
+        default = pkgs.writeText "epgstation-password" defaultPassword;
+        example = "/run/keys/epgstation-password";
+        description = ''
+          A file containing the password for <option>basicAuth.user</option>.
+        '';
+      };
+    };
+
+    database =  {
+      name = mkOption {
+        type = types.str;
+        default = "epgstation";
+        description = ''
+          Name of the MySQL database that holds EPGStation's data.
+        '';
+      };
+
+      passwordFile = mkOption {
+        type = types.path;
+        default = pkgs.writeText "epgstation-db-password" defaultPassword;
+        example = "/run/keys/epgstation-db-password";
+        description = ''
+          A file containing the password for the database named
+          <option>database.name</option>.
+        '';
+      };
+    };
+
+    settings = mkOption {
+      description = ''
+        Options to add to config.json.
+
+        Documentation:
+        <link xlink:href="https://github.com/l3tnun/EPGStation/blob/master/doc/conf-manual.md"/>
+      '';
+
+      default = {};
+      example = {
+        recPriority = 20;
+        conflictPriority = 10;
+      };
+
+      type = types.submodule {
+        freeformType = settingsFmt.type;
+
+        options.readOnlyOnce = mkOption {
+          type = types.bool;
+          default = false;
+          description = "Don't reload configuration files at runtime.";
+        };
+
+        options.mirakurunPath = mkOption (let
+          sockPath = config.services.mirakurun.unixSocket;
+        in {
+          type = types.str;
+          default = "http+unix://${replaceStrings ["/"] ["%2F"] sockPath}";
+          example = "http://localhost:40772";
+          description = "URL to connect to Mirakurun.";
+        });
+
+        options.encode = mkOption {
+          type = with types; listOf attrs;
+          description = "Encoding presets for recorded videos.";
+          default = [
+            { name = "H264";
+              cmd = "${pkgs.epgstation}/libexec/enc.sh main";
+              suffix = ".mp4";
+              default = true; }
+            { name = "H264-sub";
+              cmd = "${pkgs.epgstation}/libexec/enc.sh sub";
+              suffix = "-sub.mp4"; }
+          ];
+        };
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    environment.etc = {
+      "epgstation/operatorLogConfig.json".text = builtins.toJSON logConfig;
+      "epgstation/serviceLogConfig.json".text = builtins.toJSON logConfig;
+    };
+
+    networking.firewall = mkIf cfg.openFirewall {
+      allowedTCPPorts = with cfg; [ port socketioPort ];
+    };
+
+    users.users.epgstation = {
+      description = "EPGStation user";
+      group = config.users.groups.epgstation.name;
+      isSystemUser = true;
+    };
+
+    users.groups.epgstation = {};
+
+    services.mirakurun.enable = mkDefault true;
+
+    services.mysql = {
+      enable = mkDefault true;
+      package = mkDefault pkgs.mysql;
+      ensureDatabases = [ cfg.database.name ];
+      # FIXME: enable once mysqljs supports auth_socket
+      # ensureUsers = [ {
+      #   name = username;
+      #   ensurePermissions = { "${cfg.database.name}.*" = "ALL PRIVILEGES"; };
+      # } ];
+    };
+
+    services.epgstation.settings = let
+      defaultSettings = {
+        serverPort = cfg.port;
+        socketioPort = cfg.socketioPort;
+        clientSocketioPort = cfg.clientSocketioPort;
+
+        dbType = mkDefault "mysql";
+        mysql = {
+          user = username;
+          database = cfg.database.name;
+          socketPath = mkDefault "/run/mysqld/mysqld.sock";
+          password = mkDefault "@dbPassword@";
+          connectTimeout = mkDefault 1000;
+          connectionLimit = mkDefault 10;
+        };
+
+        basicAuth = mkIf (cfg.basicAuth.user != null) {
+          user = mkDefault cfg.basicAuth.user;
+          password = mkDefault "@password@";
+        };
+
+        ffmpeg = mkDefault "${pkgs.ffmpeg-full}/bin/ffmpeg";
+        ffprobe = mkDefault "${pkgs.ffmpeg-full}/bin/ffprobe";
+
+        fileExtension = mkDefault ".m2ts";
+        maxEncode = mkDefault 2;
+        maxStreaming = mkDefault 2;
+      };
+    in
+    mkMerge [
+      defaultSettings
+      (mkIf cfg.usePreconfiguredStreaming streamingConfig)
+    ];
+
+    systemd.tmpfiles.rules = [
+      "d '/var/lib/epgstation/streamfiles' - ${username} ${groupname} - -"
+      "d '/var/lib/epgstation/recorded' - ${username} ${groupname} - -"
+      "d '/var/lib/epgstation/thumbnail' - ${username} ${groupname} - -"
+    ];
+
+    systemd.services.epgstation = {
+      description = pkgs.epgstation.meta.description;
+      wantedBy = [ "multi-user.target" ];
+      after = [
+        "network.target"
+      ] ++ optional config.services.mirakurun.enable "mirakurun.service"
+        ++ optional config.services.mysql.enable "mysql.service";
+
+      serviceConfig = {
+        ExecStart = "${pkgs.epgstation}/bin/epgstation start";
+        ExecStartPre = "+${preStartScript}";
+        User = username;
+        Group = groupname;
+        StateDirectory = "epgstation";
+        LogsDirectory = "epgstation";
+        ConfigurationDirectory = "epgstation";
+      };
+    };
+  };
+}
diff --git a/nixos/modules/services/video/epgstation/generate b/nixos/modules/services/video/epgstation/generate
new file mode 100755
index 0000000000000..2940768b6d2c8
--- /dev/null
+++ b/nixos/modules/services/video/epgstation/generate
@@ -0,0 +1,31 @@
+#!/usr/bin/env -S nix-build --no-out-link
+
+# Script to generate default streaming configurations for EPGStation. There's
+# no need to run this script directly since generate.sh in the EPGStation
+# package directory would run this script for you.
+#
+# Usage: ./generate | xargs cat > streaming.json
+
+{ pkgs ? (import ../../../../.. {}) }:
+
+let
+  sampleConfigPath = "${pkgs.epgstation.src}/config/config.sample.json";
+  sampleConfig = builtins.fromJSON (builtins.readFile sampleConfigPath);
+  streamingConfig = {
+    inherit (sampleConfig)
+      mpegTsStreaming
+      mpegTsViewer
+      liveHLS
+      liveMP4
+      liveWebM
+      recordedDownloader
+      recordedStreaming
+      recordedViewer
+      recordedHLS;
+  };
+in
+pkgs.runCommand "streaming.json" { nativeBuildInputs = [ pkgs.jq ]; } ''
+  jq . <<<'${builtins.toJSON streamingConfig}' > $out
+''
+
+# vim:set ft=nix:
diff --git a/nixos/modules/services/video/epgstation/streaming.json b/nixos/modules/services/video/epgstation/streaming.json
new file mode 100644
index 0000000000000..37957f6cb6a22
--- /dev/null
+++ b/nixos/modules/services/video/epgstation/streaming.json
@@ -0,0 +1,119 @@
+{
+  "liveHLS": [
+    {
+      "cmd": "%FFMPEG% -re -dual_mono_mode main -i pipe:0 -sn -threads 0 -map 0 -ignore_unknown -max_muxing_queue_size 1024 -f hls -hls_time 3 -hls_list_size 17 -hls_allow_cache 1 -hls_segment_filename %streamFileDir%/stream%streamNum%-%09d.ts -c:a aac -ar 48000 -b:a 192k -ac 2 -c:v libx264 -vf yadif,scale=-2:720 -b:v 3000k -preset veryfast -flags +loop-global_header %OUTPUT%",
+      "name": "720p"
+    },
+    {
+      "cmd": "%FFMPEG% -re -dual_mono_mode main -i pipe:0 -sn -threads 0 -map 0 -ignore_unknown -max_muxing_queue_size 1024 -f hls -hls_time 3 -hls_list_size 17 -hls_allow_cache 1 -hls_segment_filename %streamFileDir%/stream%streamNum%-%09d.ts -c:a aac -ar 48000 -b:a 128k -ac 2 -c:v libx264 -vf yadif,scale=-2:480 -b:v 1500k -preset veryfast -flags +loop-global_header %OUTPUT%",
+      "name": "480p"
+    },
+    {
+      "cmd": "%FFMPEG% -re -dual_mono_mode main -i pipe:0 -sn -threads 0 -map 0 -ignore_unknown -max_muxing_queue_size 1024 -f hls -hls_time 3 -hls_list_size 17 -hls_allow_cache 1 -hls_segment_filename %streamFileDir%/stream%streamNum%-%09d.ts -c:a aac -ar 48000 -b:a 48k -ac 2 -c:v libx264 -vf yadif,scale=-2:180 -b:v 100k -preset veryfast -maxrate 110k -bufsize 1000k -flags +loop-global_header %OUTPUT%",
+      "name": "180p"
+    }
+  ],
+  "liveMP4": [
+    {
+      "cmd": "%FFMPEG% -re -dual_mono_mode main -i pipe:0 -sn -threads 0 -c:a aac -ar 48000 -b:a 192k -ac 2 -c:v libx264 -vf yadif,scale=-2:720 -b:v 3000k -profile:v baseline -preset veryfast -tune fastdecode,zerolatency -movflags frag_keyframe+empty_moov+faststart+default_base_moof -y -f mp4 pipe:1",
+      "name": "720p"
+    },
+    {
+      "cmd": "%FFMPEG% -re -dual_mono_mode main -i pipe:0 -sn -threads 0 -c:a aac -ar 48000 -b:a 128k -ac 2 -c:v libx264 -vf yadif,scale=-2:480 -b:v 1500k -profile:v baseline -preset veryfast -tune fastdecode,zerolatency -movflags frag_keyframe+empty_moov+faststart+default_base_moof -y -f mp4 pipe:1",
+      "name": "480p"
+    }
+  ],
+  "liveWebM": [
+    {
+      "cmd": "%FFMPEG% -re -dual_mono_mode main -i pipe:0 -sn -threads 3 -c:a libvorbis -ar 48000 -b:a 192k -ac 2 -c:v libvpx-vp9 -vf yadif,scale=-2:720 -b:v 3000k -deadline realtime -speed 4 -cpu-used -8 -y -f webm pipe:1",
+      "name": "720p"
+    },
+    {
+      "cmd": "%FFMPEG% -re -dual_mono_mode main -i pipe:0 -sn -threads 2 -c:a libvorbis -ar 48000 -b:a 128k -ac 2 -c:v libvpx-vp9 -vf yadif,scale=-2:480 -b:v 1500k -deadline realtime -speed 4 -cpu-used -8 -y -f webm pipe:1",
+      "name": "480p"
+    }
+  ],
+  "mpegTsStreaming": [
+    {
+      "cmd": "%FFMPEG% -re -dual_mono_mode main -i pipe:0 -sn -threads 0 -c:a aac -ar 48000 -b:a 192k -ac 2 -c:v libx264 -vf yadif,scale=-2:720 -b:v 3000k -preset veryfast -y -f mpegts pipe:1",
+      "name": "720p"
+    },
+    {
+      "cmd": "%FFMPEG% -re -dual_mono_mode main -i pipe:0 -sn -threads 0 -c:a aac -ar 48000 -b:a 128k -ac 2 -c:v libx264 -vf yadif,scale=-2:480 -b:v 1500k -preset veryfast -y -f mpegts pipe:1",
+      "name": "480p"
+    },
+    {
+      "name": "Original"
+    }
+  ],
+  "mpegTsViewer": {
+    "android": "intent://ADDRESS#Intent;package=com.mxtech.videoplayer.ad;type=video;scheme=http;end",
+    "ios": "vlc-x-callback://x-callback-url/stream?url=http://ADDRESS"
+  },
+  "recordedDownloader": {
+    "android": "intent://ADDRESS#Intent;package=com.dv.adm;type=video;scheme=http;end",
+    "ios": "vlc-x-callback://x-callback-url/download?url=http://ADDRESS&filename=FILENAME"
+  },
+  "recordedHLS": [
+    {
+      "cmd": "%FFMPEG% -dual_mono_mode main -i %INPUT% -sn -threads 0 -map 0 -ignore_unknown -max_muxing_queue_size 1024 -f hls -hls_time 3 -hls_list_size 0 -hls_allow_cache 1 -hls_segment_filename %streamFileDir%/stream%streamNum%-%09d.ts -c:a aac -ar 48000 -b:a 192k -ac 2 -c:v libx264 -vf yadif,scale=-2:720 -b:v 3000k -preset veryfast -flags +loop-global_header %OUTPUT%",
+      "name": "720p"
+    },
+    {
+      "cmd": "%FFMPEG% -dual_mono_mode main -i %INPUT% -sn -threads 0 -map 0 -ignore_unknown -max_muxing_queue_size 1024 -f hls -hls_time 3 -hls_list_size 0 -hls_allow_cache 1 -hls_segment_filename %streamFileDir%/stream%streamNum%-%09d.ts -c:a aac -ar 48000 -b:a 128k -ac 2 -c:v libx264 -vf yadif,scale=-2:480 -b:v 1500k -preset veryfast -flags +loop-global_header %OUTPUT%",
+      "name": "480p"
+    },
+    {
+      "cmd": "%FFMPEG% -dual_mono_mode main -i %INPUT% -sn -map 0 -ignore_unknown -max_muxing_queue_size 1024 -f hls -hls_time 3 -hls_list_size 0 -hls_allow_cache 1 -hls_segment_type fmp4 -hls_fmp4_init_filename stream%streamNum%-init.mp4 -hls_segment_filename stream%streamNum%-%09d.m4s -c:a aac -ar 48000 -b:a 128k -ac 2 -c:v libx265 -vf yadif,scale=-2:480 -b:v 350k -preset veryfast -tag:v hvc1 %OUTPUT%",
+      "name": "480p(h265)"
+    }
+  ],
+  "recordedStreaming": {
+    "mp4": [
+      {
+        "ab": "192k",
+        "cmd": "%FFMPEG% -dual_mono_mode main %RE% -i pipe:0 -sn -threads 0 -c:a aac -ar 48000 -ac 2 -c:v libx264 -vf yadif,scale=-2:720 %VB% %VBUFFER% %AB% %ABUFFER% -profile:v baseline -preset veryfast -tune fastdecode,zerolatency -movflags frag_keyframe+empty_moov+faststart+default_base_moof -y -f mp4 pipe:1",
+        "name": "720p",
+        "vb": "3000k"
+      },
+      {
+        "ab": "128k",
+        "cmd": "%FFMPEG% -dual_mono_mode main %RE% -i pipe:0 -sn -threads 0 -c:a aac -ar 48000 -ac 2 -c:v libx264 -vf yadif,scale=-2:360 %VB% %VBUFFER% %AB% %ABUFFER% -profile:v baseline -preset veryfast -tune fastdecode,zerolatency -movflags frag_keyframe+empty_moov+faststart+default_base_moof -y -f mp4 pipe:1",
+        "name": "360p",
+        "vb": "1500k"
+      }
+    ],
+    "mpegTs": [
+      {
+        "ab": "192k",
+        "cmd": "%FFMPEG% -dual_mono_mode main %RE% -i pipe:0 -sn -threads 0 -c:a aac -ar 48000 -ac 2 -c:v libx264 -vf yadif,scale=-2:720 %VB% %VBUFFER% %AB% %ABUFFER% -profile:v baseline -preset veryfast -tune fastdecode,zerolatency -y -f mpegts pipe:1",
+        "name": "720p (H.264)",
+        "vb": "3000k"
+      },
+      {
+        "ab": "128k",
+        "cmd": "%FFMPEG% -dual_mono_mode main %RE% -i pipe:0 -sn -threads 0 -c:a aac -ar 48000 -ac 2 -c:v libx264 -vf yadif,scale=-2:360 %VB% %VBUFFER% %AB% %ABUFFER% -profile:v baseline -preset veryfast -tune fastdecode,zerolatency -y -f mpegts pipe:1",
+        "name": "360p (H.264)",
+        "vb": "1500k"
+      }
+    ],
+    "webm": [
+      {
+        "ab": "192k",
+        "cmd": "%FFMPEG% -dual_mono_mode main %RE% -i pipe:0 -sn -threads 3 -c:a libvorbis -ar 48000 -ac 2 -c:v libvpx-vp9 -vf yadif,scale=-2:720 %VB% %VBUFFER% %AB% %ABUFFER% -deadline realtime -speed 4 -cpu-used -8 -y -f webm pipe:1",
+        "name": "720p",
+        "vb": "3000k"
+      },
+      {
+        "ab": "128k",
+        "cmd": "%FFMPEG% -dual_mono_mode main %RE% -i pipe:0 -sn -threads 2 -c:a libvorbis -ar 48000 -ac 2 -c:v libvpx-vp9 -vf yadif,scale=-2:360 %VB% %VBUFFER% %AB% %ABUFFER% -deadline realtime -speed 4 -cpu-used -8 -y -f webm pipe:1",
+        "name": "360p",
+        "vb": "1500k"
+      }
+    ]
+  },
+  "recordedViewer": {
+    "android": "intent://ADDRESS#Intent;package=com.mxtech.videoplayer.ad;type=video;scheme=http;end",
+    "ios": "infuse://x-callback-url/play?url=http://ADDRESS"
+  }
+}
diff --git a/nixos/modules/services/video/mirakurun.nix b/nixos/modules/services/video/mirakurun.nix
new file mode 100644
index 0000000000000..ce1dabe6bfa1e
--- /dev/null
+++ b/nixos/modules/services/video/mirakurun.nix
@@ -0,0 +1,183 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.mirakurun;
+  mirakurun = pkgs.mirakurun;
+  username = config.users.users.mirakurun.name;
+  groupname = config.users.users.mirakurun.group;
+  settingsFmt = pkgs.formats.yaml {};
+in
+  {
+    options = {
+      services.mirakurun = {
+        enable = mkEnableOption mirakurun.meta.description;
+
+        port = mkOption {
+          type = with types; nullOr port;
+          default = 40772;
+          description = ''
+            Port to listen on. If <literal>null</literal>, it won't listen on
+            any port.
+          '';
+        };
+
+        openFirewall = mkOption {
+          type = types.bool;
+          default = false;
+          description = ''
+            Open ports in the firewall for Mirakurun.
+
+            <warning>
+              <para>
+                Exposing Mirakurun to the open internet is generally advised
+                against. Only use it inside a trusted local network, or
+                consider putting it behind a VPN if you want remote access.
+              </para>
+            </warning>
+          '';
+        };
+
+        unixSocket = mkOption {
+          type = with types; nullOr path;
+          default = "/var/run/mirakurun/mirakurun.sock";
+          description = ''
+            Path to unix socket to listen on. If <literal>null</literal>, it
+            won't listen on any unix sockets.
+          '';
+        };
+
+        serverSettings = mkOption {
+          type = settingsFmt.type;
+          default = {};
+          example = literalExample ''
+            {
+              highWaterMark = 25165824;
+              overflowTimeLimit = 30000;
+            };
+          '';
+          description = ''
+            Options for server.yml.
+
+            Documentation:
+            <link xlink:href="https://github.com/Chinachu/Mirakurun/blob/master/doc/Configuration.md"/>
+          '';
+        };
+
+        tunerSettings = mkOption {
+          type = with types; nullOr settingsFmt.type;
+          default = null;
+          example = literalExample ''
+            [
+              {
+                name = "tuner-name";
+                types = [ "GR" "BS" "CS" "SKY" ];
+                dvbDevicePath = "/dev/dvb/adapterX/dvrX";
+              }
+            ];
+          '';
+          description = ''
+            Options which are added to tuners.yml. If none is specified, it will
+            automatically be generated at runtime.
+
+            Documentation:
+            <link xlink:href="https://github.com/Chinachu/Mirakurun/blob/master/doc/Configuration.md"/>
+          '';
+        };
+
+        channelSettings = mkOption {
+          type = with types; nullOr settingsFmt.type;
+          default = null;
+          example = literalExample ''
+            [
+              {
+                name = "channel";
+                types = "GR";
+                channel = "0";
+              }
+            ];
+          '';
+          description = ''
+            Options which are added to channels.yml. If none is specified, it
+            will automatically be generated at runtime.
+
+            Documentation:
+            <link xlink:href="https://github.com/Chinachu/Mirakurun/blob/master/doc/Configuration.md"/>
+          '';
+        };
+      };
+    };
+
+    config = mkIf cfg.enable {
+      environment.systemPackages = [ mirakurun ];
+      environment.etc = {
+        "mirakurun/server.yml".source = settingsFmt.generate "server.yml" cfg.serverSettings;
+        "mirakurun/tuners.yml" = mkIf (cfg.tunerSettings != null) {
+          source = settingsFmt.generate "tuners.yml" cfg.tunerSettings;
+          mode = "0644";
+          user = username;
+          group = groupname;
+        };
+        "mirakurun/channels.yml" = mkIf (cfg.channelSettings != null) {
+          source = settingsFmt.generate "channels.yml" cfg.channelSettings;
+          mode = "0644";
+          user = username;
+          group = groupname;
+        };
+      };
+
+      networking.firewall = mkIf cfg.openFirewall {
+        allowedTCPPorts = mkIf (cfg.port != null) [ cfg.port ];
+      };
+
+      users.users.mirakurun = {
+        description = "Mirakurun user";
+        group = "video";
+        isSystemUser = true;
+      };
+
+      services.mirakurun.serverSettings = {
+        logLevel = mkDefault 2;
+        path = mkIf (cfg.unixSocket != null) cfg.unixSocket;
+        port = mkIf (cfg.port != null) cfg.port;
+      };
+
+      systemd.tmpfiles.rules = [
+        "d '/etc/mirakurun' - ${username} ${groupname} - -"
+      ];
+
+      systemd.services.mirakurun = {
+        description = mirakurun.meta.description;
+        wantedBy = [ "multi-user.target" ];
+        after = [ "network.target" ];
+        serviceConfig = {
+          ExecStart = "${mirakurun}/bin/mirakurun";
+          User = username;
+          Group = groupname;
+          RuntimeDirectory="mirakurun";
+          StateDirectory="mirakurun";
+          Nice = -10;
+          IOSchedulingClass = "realtime";
+          IOSchedulingPriority = 7;
+        };
+
+        environment = {
+          SERVER_CONFIG_PATH = "/etc/mirakurun/server.yml";
+          TUNERS_CONFIG_PATH = "/etc/mirakurun/tuners.yml";
+          CHANNELS_CONFIG_PATH = "/etc/mirakurun/channels.yml";
+          SERVICES_DB_PATH = "/var/lib/mirakurun/services.json";
+          PROGRAMS_DB_PATH = "/var/lib/mirakurun/programs.json";
+          NODE_ENV = "production";
+        };
+
+        restartTriggers = let
+          getconf = target: config.environment.etc."mirakurun/${target}.yml".source;
+          targets = [
+            "server"
+          ] ++ optional (cfg.tunerSettings != null) "tuners"
+            ++ optional (cfg.channelSettings != null) "channels";
+        in (map getconf targets);
+      };
+    };
+  }
diff --git a/nixos/modules/services/wayland/cage.nix b/nixos/modules/services/wayland/cage.nix
index c59ca9983a6c6..14d84c4ce0f99 100644
--- a/nixos/modules/services/wayland/cage.nix
+++ b/nixos/modules/services/wayland/cage.nix
@@ -73,8 +73,6 @@ in {
         TTYVTDisallocate = "yes";
         # Fail to start if not controlling the virtual terminal.
         StandardInput = "tty-fail";
-        StandardOutput = "syslog";
-        StandardError = "syslog";
         # Set up a full (custom) user session for the user, required by Cage.
         PAMName = "cage";
       };
@@ -84,6 +82,7 @@ in {
       auth    required pam_unix.so nullok
       account required pam_unix.so
       session required pam_unix.so
+      session required pam_env.so conffile=${config.system.build.pamEnvironment} readenv=0
       session required ${pkgs.systemd}/lib/security/pam_systemd.so
     '';
 
diff --git a/nixos/modules/services/web-apps/codimd.nix b/nixos/modules/services/web-apps/codimd.nix
index 751f81649ddb4..ab922a38e5c68 100644
--- a/nixos/modules/services/web-apps/codimd.nix
+++ b/nixos/modules/services/web-apps/codimd.nix
@@ -93,7 +93,7 @@ in
           type = types.bool;
           default = true;
           description = ''
-            Wheter to enable HSTS if HTTPS is also enabled.
+            Whether to enable HSTS if HTTPS is also enabled.
           '';
         };
         maxAgeSeconds = mkOption {
@@ -385,7 +385,7 @@ in
         type = types.bool;
         default = true;
         description = ''
-          Wether to enable email registration.
+          Whether to enable email registration.
         '';
       };
       allowGravatar = mkOption {
diff --git a/nixos/modules/services/web-apps/convos.nix b/nixos/modules/services/web-apps/convos.nix
new file mode 100644
index 0000000000000..8be11eec9f31d
--- /dev/null
+++ b/nixos/modules/services/web-apps/convos.nix
@@ -0,0 +1,72 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.convos;
+in
+{
+  options.services.convos = {
+    enable = mkEnableOption "Convos";
+    listenPort = mkOption {
+      type = types.port;
+      default = 3000;
+      example = 8080;
+      description = "Port the web interface should listen on";
+    };
+    listenAddress = mkOption {
+      type = types.str;
+      default = "*";
+      example = "127.0.0.1";
+      description = "Address or host the web interface should listen on";
+    };
+    reverseProxy = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Enables reverse proxy support. This will allow Convos to automatically
+        pick up the <literal>X-Forwarded-For</literal> and
+        <literal>X-Request-Base</literal> HTTP headers set in your reverse proxy
+        web server. Note that enabling this option without a reverse proxy in
+        front will be a security issue.
+      '';
+    };
+  };
+  config = mkIf cfg.enable {
+    systemd.services.convos = {
+      description = "Convos Service";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "networking.target" ];
+      environment = {
+        CONVOS_HOME = "%S/convos";
+        CONVOS_REVERSE_PROXY = if cfg.reverseProxy then "1" else "0";
+        MOJO_LISTEN = "http://${toString cfg.listenAddress}:${toString cfg.listenPort}";
+      };
+      serviceConfig = {
+        ExecStart = "${pkgs.convos}/bin/convos daemon";
+        Restart = "on-failure";
+        StateDirectory = "convos";
+        WorkingDirectory = "%S/convos";
+        DynamicUser = true;
+        MemoryDenyWriteExecute = true;
+        ProtectHome = true;
+        ProtectClock = true;
+        ProtectHostname = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectKernelLogs = true;
+        ProtectControlGroups = true;
+        PrivateDevices = true;
+        PrivateMounts = true;
+        PrivateUsers = true;
+        LockPersonality = true;
+        RestrictRealtime = true;
+        RestrictNamespaces = true;
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6"];
+        SystemCallFilter = "@system-service";
+        SystemCallArchitectures = "native";
+        CapabilityBoundingSet = "";
+      };
+    };
+  };
+}
diff --git a/nixos/modules/services/web-apps/dokuwiki.nix b/nixos/modules/services/web-apps/dokuwiki.nix
index 33a828fa2cb3b..d9ebb3a98808c 100644
--- a/nixos/modules/services/web-apps/dokuwiki.nix
+++ b/nixos/modules/services/web-apps/dokuwiki.nix
@@ -2,7 +2,7 @@
 
 let
 
-  inherit (lib) mkEnableOption mkForce mkIf mkMerge mkOption optionalAttrs recursiveUpdate types;
+  inherit (lib) mkEnableOption mkForce mkIf mkMerge mkOption optionalAttrs recursiveUpdate types maintainers;
   inherit (lib) concatMapStringsSep flatten mapAttrs mapAttrs' mapAttrsToList nameValuePair concatMapStringSep;
 
   eachSite = config.services.dokuwiki;
@@ -95,7 +95,7 @@ let
 
       aclFile = mkOption {
         type = with types; nullOr str;
-        default = if (config.aclUse && config.acl == null) then "/var/lib/dokuwiki/${name}/users.auth.php" else null;
+        default = if (config.aclUse && config.acl == null) then "/var/lib/dokuwiki/${name}/acl.auth.php" else null;
         description = ''
           Location of the dokuwiki acl rules. Mutually exclusive with services.dokuwiki.acl
           Mutually exclusive with services.dokuwiki.acl which is preferred.
@@ -249,22 +249,19 @@ let
       nginx = mkOption {
         type = types.submodule (
           recursiveUpdate
-            (import ../web-servers/nginx/vhost-options.nix { inherit config lib; })
-            {
-              # Enable encryption by default,
-              options.forceSSL.default = true;
-              options.enableACME.default = true;
-            }
+            (import ../web-servers/nginx/vhost-options.nix { inherit config lib; }) {}
         );
-        default = {forceSSL = true; enableACME = true;};
+        default = {};
         example = {
           serverAliases = [
             "wiki.\${config.networking.domain}"
           ];
-          enableACME = false;
+          # To enable encryption and let let's encrypt take care of certificate
+          forceSSL = true;
+          enableACME = true;
         };
         description = ''
-          With this option, you can customize the nginx virtualHost which already has sensible defaults for DokuWiki.
+          With this option, you can customize the nginx virtualHost settings.
         '';
       };
     };
@@ -276,7 +273,7 @@ in
     services.dokuwiki = mkOption {
       type = types.attrsOf (types.submodule siteOpts);
       default = {};
-      description = "Sepcification of one or more dokuwiki sites to service.";
+      description = "Sepcification of one or more dokuwiki sites to serve.";
     };
   };
 
@@ -321,7 +318,7 @@ in
       enable = true;
       virtualHosts = mapAttrs (hostName: cfg:  mkMerge [ cfg.nginx {
         root = mkForce "${pkg hostName cfg}/share/dokuwiki";
-        extraConfig = "fastcgi_param HTTPS on;";
+        extraConfig = lib.optionalString (cfg.nginx.addSSL || cfg.nginx.forceSSL || cfg.nginx.onlySSL || cfg.nginx.enableACME) "fastcgi_param HTTPS on;";
 
         locations."~ /(conf/|bin/|inc/|install.php)" = {
           extraConfig = "deny all;";
@@ -359,7 +356,7 @@ in
               fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
               fastcgi_param REDIRECT_STATUS 200;
               fastcgi_pass unix:${config.services.phpfpm.pools."dokuwiki-${hostName}".socket};
-              fastcgi_param HTTPS on;
+              ${lib.optionalString (cfg.nginx.addSSL || cfg.nginx.forceSSL || cfg.nginx.onlySSL || cfg.nginx.enableACME) "fastcgi_param HTTPS on;"}
           '';
         };
       }]) eachSite;
@@ -385,4 +382,7 @@ in
       isSystemUser = true;
     };
   };
+
+  meta.maintainers = with maintainers; [ _1000101 ];
+
 }
diff --git a/nixos/modules/services/web-apps/gerrit.nix b/nixos/modules/services/web-apps/gerrit.nix
index b184c0754d45b..657b1a4fc5bac 100644
--- a/nixos/modules/services/web-apps/gerrit.nix
+++ b/nixos/modules/services/web-apps/gerrit.nix
@@ -17,6 +17,10 @@ let
     lib.generators.toGitINI cfg.settings
   );
 
+  replicationConfig = pkgs.writeText "replication.conf" (
+    lib.generators.toGitINI cfg.replicationSettings
+  );
+
   # Wrap the gerrit java with all the java options so it can be called
   # like a normal CLI app
   gerrit-cli = pkgs.writeShellScriptBin "gerrit" ''
@@ -106,6 +110,15 @@ in
         '';
       };
 
+      replicationSettings = mkOption {
+        type = gitIniType;
+        default = {};
+        description = ''
+          Replication configuration. This will be generated to the
+          <literal>etc/replication.config</literal> file.
+        '';
+      };
+
       plugins = mkOption {
         type = types.listOf types.package;
         default = [];
@@ -138,6 +151,13 @@ in
 
   config = mkIf cfg.enable {
 
+    assertions = [
+      {
+        assertion = cfg.replicationSettings != {} -> elem "replication" cfg.builtinPlugins;
+        message = "Gerrit replicationSettings require enabling the replication plugin";
+      }
+    ];
+
     services.gerrit.settings = {
       cache.directory = "/var/cache/gerrit";
       container.heapLimit = cfg.jvmHeapLimit;
@@ -194,6 +214,7 @@ in
 
         # copy the config, keep it mutable because Gerrit
         ln -sfv ${gerritConfig} etc/gerrit.config
+        ln -sfv ${replicationConfig} etc/replication.config
 
         # install the plugins
         rm -rf plugins
diff --git a/nixos/modules/services/web-apps/jitsi-meet.nix b/nixos/modules/services/web-apps/jitsi-meet.nix
new file mode 100644
index 0000000000000..2df762882faea
--- /dev/null
+++ b/nixos/modules/services/web-apps/jitsi-meet.nix
@@ -0,0 +1,334 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.jitsi-meet;
+
+  # The configuration files are JS of format "var <<string>> = <<JSON>>;". In order to
+  # override only some settings, we need to extract the JSON, use jq to merge it with
+  # the config provided by user, and then reconstruct the file.
+  overrideJs =
+    source: varName: userCfg: appendExtra:
+    let
+      extractor = pkgs.writeText "extractor.js" ''
+        var fs = require("fs");
+        eval(fs.readFileSync(process.argv[2], 'utf8'));
+        process.stdout.write(JSON.stringify(eval(process.argv[3])));
+      '';
+      userJson = pkgs.writeText "user.json" (builtins.toJSON userCfg);
+    in (pkgs.runCommand "${varName}.js" { } ''
+      ${pkgs.nodejs}/bin/node ${extractor} ${source} ${varName} > default.json
+      (
+        echo "var ${varName} = "
+        ${pkgs.jq}/bin/jq -s '.[0] * .[1]' default.json ${userJson}
+        echo ";"
+        echo ${escapeShellArg appendExtra}
+      ) > $out
+    '');
+
+  # Essential config - it's probably not good to have these as option default because
+  # types.attrs doesn't do merging. Let's merge explicitly, can still be overriden if
+  # user desires.
+  defaultCfg = {
+    hosts = {
+      domain = cfg.hostName;
+      muc = "conference.${cfg.hostName}";
+      focus = "focus.${cfg.hostName}";
+    };
+    bosh = "//${cfg.hostName}/http-bind";
+  };
+in
+{
+  options.services.jitsi-meet = with types; {
+    enable = mkEnableOption "Jitsi Meet - Secure, Simple and Scalable Video Conferences";
+
+    hostName = mkOption {
+      type = str;
+      example = "meet.example.org";
+      description = ''
+        Hostname of the Jitsi Meet instance.
+      '';
+    };
+
+    config = mkOption {
+      type = attrs;
+      default = { };
+      example = literalExample ''
+        {
+          enableWelcomePage = false;
+          defaultLang = "fi";
+        }
+      '';
+      description = ''
+        Client-side web application settings that override the defaults in <filename>config.js</filename>.
+
+        See <link xlink:href="https://github.com/jitsi/jitsi-meet/blob/master/config.js" /> for default
+        configuration with comments.
+      '';
+    };
+
+    extraConfig = mkOption {
+      type = lines;
+      default = "";
+      description = ''
+        Text to append to <filename>config.js</filename> web application config file.
+
+        Can be used to insert JavaScript logic to determine user's region in cascading bridges setup.
+      '';
+    };
+
+    interfaceConfig = mkOption {
+      type = attrs;
+      default = { };
+      example = literalExample ''
+        {
+          SHOW_JITSI_WATERMARK = false;
+          SHOW_WATERMARK_FOR_GUESTS = false;
+        }
+      '';
+      description = ''
+        Client-side web-app interface settings that override the defaults in <filename>interface_config.js</filename>.
+
+        See <link xlink:href="https://github.com/jitsi/jitsi-meet/blob/master/interface_config.js" /> for
+        default configuration with comments.
+      '';
+    };
+
+    videobridge = {
+      enable = mkOption {
+        type = bool;
+        default = true;
+        description = ''
+          Whether to enable Jitsi Videobridge instance and configure it to connect to Prosody.
+
+          Additional configuration is possible with <option>services.jitsi-videobridge</option>.
+        '';
+      };
+
+      passwordFile = mkOption {
+        type = nullOr str;
+        default = null;
+        example = "/run/keys/videobridge";
+        description = ''
+          File containing password to the Prosody account for videobridge.
+
+          If <literal>null</literal>, a file with password will be generated automatically. Setting
+          this option is useful if you plan to connect additional videobridges to the XMPP server.
+        '';
+      };
+    };
+
+    jicofo.enable = mkOption {
+      type = bool;
+      default = true;
+      description = ''
+        Whether to enable JiCoFo instance and configure it to connect to Prosody.
+
+        Additional configuration is possible with <option>services.jicofo</option>.
+      '';
+    };
+
+    nginx.enable = mkOption {
+      type = bool;
+      default = true;
+      description = ''
+        Whether to enable nginx virtual host that will serve the javascript application and act as
+        a proxy for the XMPP server. Further nginx configuration can be done by adapting
+        <option>services.nginx.virtualHosts.&lt;hostName&gt;</option>.
+        When this is enabled, ACME will be used to retrieve a TLS certificate by default. To disable
+        this, set the <option>services.nginx.virtualHosts.&lt;hostName&gt;.enableACME</option> to
+        <literal>false</literal> and if appropriate do the same for
+        <option>services.nginx.virtualHosts.&lt;hostName&gt;.forceSSL</option>.
+      '';
+    };
+
+    prosody.enable = mkOption {
+      type = bool;
+      default = true;
+      description = ''
+        Whether to configure Prosody to relay XMPP messages between Jitsi Meet components. Turn this
+        off if you want to configure it manually.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    services.prosody = mkIf cfg.prosody.enable {
+      enable = mkDefault true;
+      xmppComplianceSuite = mkDefault false;
+      modules = {
+        admin_adhoc = mkDefault false;
+        bosh = mkDefault true;
+        ping = mkDefault true;
+        roster = mkDefault true;
+        saslauth = mkDefault true;
+        tls = mkDefault true;
+      };
+      muc = [
+        {
+          domain = "conference.${cfg.hostName}";
+          name = "Jitsi Meet MUC";
+          roomLocking = false;
+          roomDefaultPublicJids = true;
+          extraConfig = ''
+            storage = "memory"
+          '';
+        }
+        {
+          domain = "internal.${cfg.hostName}";
+          name = "Jitsi Meet Videobridge MUC";
+          extraConfig = ''
+            storage = "memory"
+            admins = { "focus@auth.${cfg.hostName}", "jvb@auth.${cfg.hostName}" }
+          '';
+          #-- muc_room_cache_size = 1000
+        }
+      ];
+      extraModules = [ "pubsub" ];
+      extraConfig = mkAfter ''
+        Component "focus.${cfg.hostName}"
+          component_secret = os.getenv("JICOFO_COMPONENT_SECRET")
+      '';
+      virtualHosts.${cfg.hostName} = {
+        enabled = true;
+        domain = cfg.hostName;
+        extraConfig = ''
+          authentication = "anonymous"
+          c2s_require_encryption = false
+          admins = { "focus@auth.${cfg.hostName}" }
+        '';
+        ssl = {
+          cert = "/var/lib/jitsi-meet/jitsi-meet.crt";
+          key = "/var/lib/jitsi-meet/jitsi-meet.key";
+        };
+      };
+      virtualHosts."auth.${cfg.hostName}" = {
+        enabled = true;
+        domain = "auth.${cfg.hostName}";
+        extraConfig = ''
+          authentication = "internal_plain"
+        '';
+        ssl = {
+          cert = "/var/lib/jitsi-meet/jitsi-meet.crt";
+          key = "/var/lib/jitsi-meet/jitsi-meet.key";
+        };
+      };
+    };
+    systemd.services.prosody.serviceConfig = mkIf cfg.prosody.enable {
+      EnvironmentFile = [ "/var/lib/jitsi-meet/secrets-env" ];
+      SupplementaryGroups = [ "jitsi-meet" ];
+    };
+
+    users.groups.jitsi-meet = {};
+    systemd.tmpfiles.rules = [
+      "d '/var/lib/jitsi-meet' 0750 root jitsi-meet - -"
+    ];
+
+    systemd.services.jitsi-meet-init-secrets = {
+      wantedBy = [ "multi-user.target" ];
+      before = [ "jicofo.service" "jitsi-videobridge2.service" ] ++ (optional cfg.prosody.enable "prosody.service");
+      serviceConfig = {
+        Type = "oneshot";
+      };
+
+      script = let
+        secrets = [ "jicofo-component-secret" "jicofo-user-secret" ] ++ (optional (cfg.videobridge.passwordFile == null) "videobridge-secret");
+        videobridgeSecret = if cfg.videobridge.passwordFile != null then cfg.videobridge.passwordFile else "/var/lib/jitsi-meet/videobridge-secret";
+      in
+      ''
+        cd /var/lib/jitsi-meet
+        ${concatMapStringsSep "\n" (s: ''
+          if [ ! -f ${s} ]; then
+            tr -dc a-zA-Z0-9 </dev/urandom | head -c 64 > ${s}
+            chown root:jitsi-meet ${s}
+            chmod 640 ${s}
+          fi
+        '') secrets}
+
+        # for easy access in prosody
+        echo "JICOFO_COMPONENT_SECRET=$(cat jicofo-component-secret)" > secrets-env
+        chown root:jitsi-meet secrets-env
+        chmod 640 secrets-env
+      ''
+      + optionalString cfg.prosody.enable ''
+        ${config.services.prosody.package}/bin/prosodyctl register focus auth.${cfg.hostName} "$(cat /var/lib/jitsi-meet/jicofo-user-secret)"
+        ${config.services.prosody.package}/bin/prosodyctl register jvb auth.${cfg.hostName} "$(cat ${videobridgeSecret})"
+
+        # generate self-signed certificates
+        if [ ! -f /var/lib/jitsi-meet.crt ]; then
+          ${getBin pkgs.openssl}/bin/openssl req \
+            -x509 \
+            -newkey rsa:4096 \
+            -keyout /var/lib/jitsi-meet/jitsi-meet.key \
+            -out /var/lib/jitsi-meet/jitsi-meet.crt \
+            -days 36500 \
+            -nodes \
+            -subj '/CN=${cfg.hostName}/CN=auth.${cfg.hostName}'
+          chmod 640 /var/lib/jitsi-meet/jitsi-meet.{crt,key}
+          chown root:jitsi-meet /var/lib/jitsi-meet/jitsi-meet.{crt,key}
+        fi
+      '';
+    };
+
+    services.nginx = mkIf cfg.nginx.enable {
+      enable = mkDefault true;
+      virtualHosts.${cfg.hostName} = {
+        enableACME = mkDefault true;
+        forceSSL = mkDefault true;
+        root = pkgs.jitsi-meet;
+        extraConfig = ''
+          ssi on;
+        '';
+        locations."@root_path".extraConfig = ''
+          rewrite ^/(.*)$ / break;
+        '';
+        locations."~ ^/([^/\\?&:'\"]+)$".tryFiles = "$uri @root_path";
+        locations."=/http-bind" = {
+          proxyPass = "http://localhost:5280/http-bind";
+          extraConfig = ''
+            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+            proxy_set_header Host $host;
+          '';
+        };
+        locations."=/external_api.js" = mkDefault {
+          alias = "${pkgs.jitsi-meet}/libs/external_api.min.js";
+        };
+        locations."=/config.js" = mkDefault {
+          alias = overrideJs "${pkgs.jitsi-meet}/config.js" "config" (recursiveUpdate defaultCfg cfg.config) cfg.extraConfig;
+        };
+        locations."=/interface_config.js" = mkDefault {
+          alias = overrideJs "${pkgs.jitsi-meet}/interface_config.js" "interfaceConfig" cfg.interfaceConfig "";
+        };
+      };
+    };
+
+    services.jitsi-videobridge = mkIf cfg.videobridge.enable {
+      enable = true;
+      xmppConfigs."localhost" = {
+        userName = "jvb";
+        domain = "auth.${cfg.hostName}";
+        passwordFile = "/var/lib/jitsi-meet/videobridge-secret";
+        mucJids = "jvbbrewery@internal.${cfg.hostName}";
+        disableCertificateVerification = true;
+      };
+    };
+
+    services.jicofo = mkIf cfg.jicofo.enable {
+      enable = true;
+      xmppHost = "localhost";
+      xmppDomain = cfg.hostName;
+      userDomain = "auth.${cfg.hostName}";
+      userName = "focus";
+      userPasswordFile = "/var/lib/jitsi-meet/jicofo-user-secret";
+      componentPasswordFile = "/var/lib/jitsi-meet/jicofo-component-secret";
+      bridgeMuc = "jvbbrewery@internal.${cfg.hostName}";
+      config = {
+        "org.jitsi.jicofo.ALWAYS_TRUST_MODE_ENABLED" = "true";
+      };
+    };
+  };
+
+  meta.doc = ./jitsi-meet.xml;
+  meta.maintainers = lib.teams.jitsi.members;
+}
diff --git a/nixos/modules/services/web-apps/jitsi-meet.xml b/nixos/modules/services/web-apps/jitsi-meet.xml
new file mode 100644
index 0000000000000..97373bc6d9a87
--- /dev/null
+++ b/nixos/modules/services/web-apps/jitsi-meet.xml
@@ -0,0 +1,55 @@
+<chapter xmlns="http://docbook.org/ns/docbook"
+         xmlns:xlink="http://www.w3.org/1999/xlink"
+         xmlns:xi="http://www.w3.org/2001/XInclude"
+         version="5.0"
+         xml:id="module-services-jitsi-meet">
+ <title>Jitsi Meet</title>
+ <para>
+   With Jitsi Meet on NixOS you can quickly configure a complete,
+   private, self-hosted video conferencing solution.
+ </para>
+
+ <section xml:id="module-services-jitsi-basic-usage">
+ <title>Basic usage</title>
+   <para>
+     A minimal configuration using Let's Encrypt for TLS certificates looks like this:
+<programlisting>{
+  services.jitsi-meet = {
+    <link linkend="opt-services.jitsi-meet.enable">enable</link> = true;
+    <link linkend="opt-services.jitsi-meet.enable">hostName</link> = "jitsi.example.com";
+  };
+  <link linkend="opt-services.jitsi-videobridge.openFirewall">services.jitsi-videobridge.openFirewall</link> = true;
+  <link linkend="opt-networking.firewall.allowedTCPPorts">networking.firewall.allowedTCPPorts</link> = [ 80 443 ];
+  <link linkend="opt-security.acme.email">security.acme.email</link> = "me@example.com";
+  <link linkend="opt-security.acme.acceptTerms">security.acme.acceptTerms</link> = true;
+}</programlisting>
+   </para>
+ </section>
+
+ <section xml:id="module-services-jitsi-configuration">
+ <title>Configuration</title>
+   <para>
+     Here is the minimal configuration with additional configurations:
+<programlisting>{
+  services.jitsi-meet = {
+    <link linkend="opt-services.jitsi-meet.enable">enable</link> = true;
+    <link linkend="opt-services.jitsi-meet.enable">hostName</link> = "jitsi.example.com";
+    <link linkend="opt-services.jitsi-meet.config">config</link> = {
+      enableWelcomePage = false;
+      prejoinPageEnabled = true;
+      defaultLang = "fi";
+    };
+    <link linkend="opt-services.jitsi-meet.interfaceConfig">interfaceConfig</link> = {
+      SHOW_JITSI_WATERMARK = false;
+      SHOW_WATERMARK_FOR_GUESTS = false;
+    };
+  };
+  <link linkend="opt-services.jitsi-videobridge.openFirewall">services.jitsi-videobridge.openFirewall</link> = true;
+  <link linkend="opt-networking.firewall.allowedTCPPorts">networking.firewall.allowedTCPPorts</link> = [ 80 443 ];
+  <link linkend="opt-security.acme.email">security.acme.email</link> = "me@example.com";
+  <link linkend="opt-security.acme.acceptTerms">security.acme.acceptTerms</link> = true;
+}</programlisting>
+   </para>
+ </section>
+
+</chapter>
diff --git a/nixos/modules/services/web-apps/moodle.nix b/nixos/modules/services/web-apps/moodle.nix
index 1196780cf6ef9..f45eaa24d544e 100644
--- a/nixos/modules/services/web-apps/moodle.nix
+++ b/nixos/modules/services/web-apps/moodle.nix
@@ -40,7 +40,7 @@ let
   $CFG->disableupdateautodeploy = true;
 
   $CFG->pathtogs = '${pkgs.ghostscript}/bin/gs';
-  $CFG->pathtophp = '${pkgs.php}/bin/php';
+  $CFG->pathtophp = '${phpExt}/bin/php';
   $CFG->pathtodu = '${pkgs.coreutils}/bin/du';
   $CFG->aspellpath = '${pkgs.aspell}/bin/aspell';
   $CFG->pathtodot = '${pkgs.graphviz}/bin/dot';
@@ -55,6 +55,9 @@ let
 
   mysqlLocal = cfg.database.createLocally && cfg.database.type == "mysql";
   pgsqlLocal = cfg.database.createLocally && cfg.database.type == "pgsql";
+
+  phpExt = pkgs.php.withExtensions
+        ({ enabled, all }: with all; [ iconv mbstring curl openssl tokenizer xmlrpc soap ctype zip gd simplexml dom  intl json sqlite3 pgsql pdo_sqlite pdo_pgsql pdo_odbc pdo_mysql pdo mysqli session zlib xmlreader fileinfo ]);
 in
 {
   # interface
@@ -222,6 +225,7 @@ in
 
     services.phpfpm.pools.moodle = {
       inherit user group;
+      phpPackage = phpExt;
       phpEnv.MOODLE_CONFIG = "${moodleConfig}";
       phpOptions = ''
         zend_extension = opcache.so
@@ -263,13 +267,13 @@ in
       after = optional mysqlLocal "mysql.service" ++ optional pgsqlLocal "postgresql.service";
       environment.MOODLE_CONFIG = moodleConfig;
       script = ''
-        ${pkgs.php}/bin/php ${cfg.package}/share/moodle/admin/cli/check_database_schema.php && rc=$? || rc=$?
+        ${phpExt}/bin/php ${cfg.package}/share/moodle/admin/cli/check_database_schema.php && rc=$? || rc=$?
 
-        [ "$rc" == 1 ] && ${pkgs.php}/bin/php ${cfg.package}/share/moodle/admin/cli/upgrade.php \
+        [ "$rc" == 1 ] && ${phpExt}/bin/php ${cfg.package}/share/moodle/admin/cli/upgrade.php \
           --non-interactive \
           --allow-unstable
 
-        [ "$rc" == 2 ] && ${pkgs.php}/bin/php ${cfg.package}/share/moodle/admin/cli/install_database.php \
+        [ "$rc" == 2 ] && ${phpExt}/bin/php ${cfg.package}/share/moodle/admin/cli/install_database.php \
           --agree-license \
           --adminpass=${cfg.initialPassword}
 
@@ -289,7 +293,7 @@ in
       serviceConfig = {
         User = user;
         Group = group;
-        ExecStart = "${pkgs.php}/bin/php ${cfg.package}/share/moodle/admin/cli/cron.php";
+        ExecStart = "${phpExt}/bin/php ${cfg.package}/share/moodle/admin/cli/cron.php";
       };
     };
 
diff --git a/nixos/modules/services/web-apps/nextcloud.nix b/nixos/modules/services/web-apps/nextcloud.nix
index 5b9065dec3c55..7da119758fc91 100644
--- a/nixos/modules/services/web-apps/nextcloud.nix
+++ b/nixos/modules/services/web-apps/nextcloud.nix
@@ -45,6 +45,22 @@ let
   inherit (config.system) stateVersion;
 
 in {
+
+  imports = [
+    (mkRemovedOptionModule [ "services" "nextcloud" "nginx" "enable" ] ''
+      The nextcloud module supports `nginx` as reverse-proxy by default and doesn't
+      support other reverse-proxies officially.
+
+      However it's possible to use an alternative reverse-proxy by
+
+        * disabling nginx
+        * setting `listen.owner` & `listen.group` in the phpfpm-pool to a different value
+
+      Further details about this can be found in the `Nextcloud`-section of the NixOS-manual
+      (which can be openend e.g. by running `nixos-help`).
+    '')
+  ];
+
   options.services.nextcloud = {
     enable = mkEnableOption "nextcloud";
     hostName = mkOption {
@@ -69,7 +85,7 @@ in {
     package = mkOption {
       type = types.package;
       description = "Which package to use for the Nextcloud instance.";
-      relatedPackages = [ "nextcloud17" "nextcloud18" ];
+      relatedPackages = [ "nextcloud17" "nextcloud18" "nextcloud19" ];
     };
 
     maxUploadSize = mkOption {
@@ -91,16 +107,6 @@ in {
       '';
     };
 
-    nginx.enable = mkOption {
-      type = types.bool;
-      default = false;
-      description = ''
-        Whether to enable nginx virtual host management.
-        Further nginx configuration can be done by adapting <literal>services.nginx.virtualHosts.&lt;name&gt;</literal>.
-        See <xref linkend="opt-services.nginx.virtualHosts"/> for further information.
-      '';
-    };
-
     webfinger = mkOption {
       type = types.bool;
       default = false;
@@ -303,6 +309,14 @@ in {
         '';
       };
     };
+    occ = mkOption {
+      type = types.package;
+      default = occ;
+      internal = true;
+      description = ''
+        The nextcloud-occ program preconfigured to target this Nextcloud instance.
+      '';
+    };
   };
 
   config = mkIf cfg.enable (mkMerge [
@@ -336,7 +350,16 @@ in {
              server, and wait until the upgrade to 17 is finished.
 
           Then, set `services.nextcloud.package` to `pkgs.nextcloud18` to upgrade to
-          Nextcloud version 18.
+          Nextcloud version 18. Please note that Nextcloud 19 is already out and it's
+          recommended to upgrade to nextcloud19 after that.
+        '')
+        ++ (optional (versionOlder cfg.package.version "19") ''
+          A legacy Nextcloud install (from before NixOS 20.09/unstable) may be installed.
+
+          If/After nextcloud18 is installed successfully, you can safely upgrade to
+          nextcloud19. If not, please upgrade to nextcloud18 first since Nextcloud doesn't
+          support upgrades that skip multiple versions (i.e. an upgrade from 17 to 19 isn't
+          possible, but an upgrade from 18 to 19).
         '');
 
       services.nextcloud.package = with pkgs;
@@ -348,7 +371,8 @@ in {
               `pkgs.nextcloud`.
             ''
           else if versionOlder stateVersion "20.03" then nextcloud17
-          else nextcloud18
+          else if versionOlder stateVersion "20.09" then nextcloud18
+          else nextcloud19
         );
     }
 
@@ -360,6 +384,11 @@ in {
       };
 
       systemd.services = {
+        # When upgrading the Nextcloud package, Nextcloud can report errors such as
+        # "The files of the app [all apps in /var/lib/nextcloud/apps] were not replaced correctly"
+        # Restarting phpfpm on Nextcloud package update fixes these issues (but this is a workaround).
+        phpfpm-nextcloud.restartTriggers = [ cfg.package ];
+
         nextcloud-setup = let
           c = cfg.config;
           writePhpArrary = a: "[${concatMapStringsSep "," (val: ''"${toString val}"'') a}]";
@@ -445,10 +474,18 @@ in {
           script = ''
             chmod og+x ${cfg.home}
             ln -sf ${cfg.package}/apps ${cfg.home}/
-            mkdir -p ${cfg.home}/config ${cfg.home}/data ${cfg.home}/store-apps
-            ln -sf ${overrideConfig} ${cfg.home}/config/override.config.php
 
-            chown -R nextcloud:nginx ${cfg.home}/config ${cfg.home}/data ${cfg.home}/store-apps
+            # create nextcloud directories.
+            # if the directories exist already with wrong permissions, we fix that
+            for dir in ${cfg.home}/config ${cfg.home}/data ${cfg.home}/store-apps; do
+              if [ ! -e $dir ]; then
+                install -o nextcloud -g nextcloud -d $dir
+              elif [ $(stat -c "%G" $dir) != "nextcloud" ]; then
+                chgrp -R nextcloud $dir
+              fi
+            done
+
+            ln -sf ${overrideConfig} ${cfg.home}/config/override.config.php
 
             # Do not install if already installed
             if [[ ! -e ${cfg.home}/config/config.php ]]; then
@@ -461,6 +498,7 @@ in {
             ${occSetTrustedDomainsCmd}
           '';
           serviceConfig.Type = "oneshot";
+          serviceConfig.User = "nextcloud";
         };
         nextcloud-cron = {
           environment.NEXTCLOUD_CONFIG_DIR = "${cfg.home}/config";
@@ -479,7 +517,7 @@ in {
       services.phpfpm = {
         pools.nextcloud = {
           user = "nextcloud";
-          group = "nginx";
+          group = "nextcloud";
           phpOptions = phpOptionsStr;
           phpPackage = phpPackage;
           phpEnv = {
@@ -487,128 +525,121 @@ in {
             PATH = "/run/wrappers/bin:/nix/var/nix/profiles/default/bin:/run/current-system/sw/bin:/usr/bin:/bin";
           };
           settings = mapAttrs (name: mkDefault) {
-            "listen.owner" = "nginx";
-            "listen.group" = "nginx";
+            "listen.owner" = config.services.nginx.user;
+            "listen.group" = config.services.nginx.group;
           } // cfg.poolSettings;
           extraConfig = cfg.poolConfig;
         };
       };
 
-      users.extraUsers.nextcloud = {
+      users.users.nextcloud = {
         home = "${cfg.home}";
-        group = "nginx";
+        group = "nextcloud";
         createHome = true;
       };
+      users.groups.nextcloud.members = [ "nextcloud" config.services.nginx.user ];
 
       environment.systemPackages = [ occ ];
-    }
 
-    (mkIf cfg.nginx.enable {
-      services.nginx = {
-        enable = true;
-        virtualHosts = {
-          ${cfg.hostName} = {
-            root = cfg.package;
-            locations = {
-              "= /robots.txt" = {
-                priority = 100;
-                extraConfig = ''
-                  allow all;
-                  log_not_found off;
-                  access_log off;
-                '';
-              };
-              "/" = {
-                priority = 200;
-                extraConfig = "rewrite ^ /index.php;";
-              };
-              "~ ^/store-apps" = {
-                priority = 201;
-                extraConfig = "root ${cfg.home};";
-              };
-              "= /.well-known/carddav" = {
-                priority = 210;
-                extraConfig = "return 301 $scheme://$host/remote.php/dav;";
-              };
-              "= /.well-known/caldav" = {
-                priority = 210;
-                extraConfig = "return 301 $scheme://$host/remote.php/dav;";
-              };
-              "~ ^\\/(?:build|tests|config|lib|3rdparty|templates|data)\\/" = {
-                priority = 300;
-                extraConfig = "deny all;";
-              };
-              "~ ^\\/(?:\\.|autotest|occ|issue|indie|db_|console)" = {
-                priority = 300;
-                extraConfig = "deny all;";
-              };
-              "~ ^\\/(?:index|remote|public|cron|core/ajax\\/update|status|ocs\\/v[12]|updater\\/.+|ocs-provider\\/.+|ocm-provider\\/.+)\\.php(?:$|\\/)" = {
-                priority = 500;
-                extraConfig = ''
-                  include ${config.services.nginx.package}/conf/fastcgi.conf;
-                  fastcgi_split_path_info ^(.+\.php)(\\/.*)$;
-                  try_files $fastcgi_script_name =404;
-                  fastcgi_param PATH_INFO $fastcgi_path_info;
-                  fastcgi_param HTTPS ${if cfg.https then "on" else "off"};
-                  fastcgi_param modHeadersAvailable true;
-                  fastcgi_param front_controller_active true;
-                  fastcgi_pass unix:${fpm.socket};
-                  fastcgi_intercept_errors on;
-                  fastcgi_request_buffering off;
-                  fastcgi_read_timeout 120s;
-                '';
-              };
-              "~ ^\\/(?:updater|ocs-provider|ocm-provider)(?:$|\\/)".extraConfig = ''
-                try_files $uri/ =404;
-                index index.php;
-              '';
-              "~ \\.(?:css|js|woff2?|svg|gif)$".extraConfig = ''
-                try_files $uri /index.php$request_uri;
-                add_header Cache-Control "public, max-age=15778463";
-                add_header X-Content-Type-Options nosniff;
-                add_header X-XSS-Protection "1; mode=block";
-                add_header X-Robots-Tag none;
-                add_header X-Download-Options noopen;
-                add_header X-Permitted-Cross-Domain-Policies none;
-                add_header X-Frame-Options sameorigin;
-                add_header Referrer-Policy no-referrer;
-                access_log off;
-              '';
-              "~ \\.(?:png|html|ttf|ico|jpg|jpeg|bcmap|mp4|webm)$".extraConfig = ''
-                try_files $uri /index.php$request_uri;
-                access_log off;
-              '';
-            };
+      services.nginx.enable = mkDefault true;
+      services.nginx.virtualHosts.${cfg.hostName} = {
+        root = cfg.package;
+        locations = {
+          "= /robots.txt" = {
+            priority = 100;
+            extraConfig = ''
+              allow all;
+              log_not_found off;
+              access_log off;
+            '';
+          };
+          "/" = {
+            priority = 900;
+            extraConfig = "try_files $uri $uri/ /index.php$request_uri;";
+          };
+          "~ ^/store-apps" = {
+            priority = 201;
+            extraConfig = "root ${cfg.home};";
+          };
+          "^~ /.well-known" = {
+            priority = 210;
+            extraConfig = ''
+              location = /.well-known/carddav {
+                return 301 $scheme://$host/remote.php/dav;
+              }
+              location = /.well-known/caldav {
+                return 301 $scheme://$host/remote.php/dav;
+              }
+              try_files $uri $uri/ =404;
+            '';
+          };
+          "~ ^/(?:build|tests|config|lib|3rdparty|templates|data)(?:$|/)".extraConfig = ''
+            return 404;
+          '';
+          "~ ^/(?:\\.|autotest|occ|issue|indie|db_|console)".extraConfig = ''
+            return 404;
+          '';
+          "~ \\.php(?:$|/)" = {
+            priority = 500;
             extraConfig = ''
-              add_header X-Content-Type-Options nosniff;
-              add_header X-XSS-Protection "1; mode=block";
-              add_header X-Robots-Tag none;
-              add_header X-Download-Options noopen;
-              add_header X-Permitted-Cross-Domain-Policies none;
-              add_header X-Frame-Options sameorigin;
-              add_header Referrer-Policy no-referrer;
-              add_header Strict-Transport-Security "max-age=15552000; includeSubDomains" always;
-              error_page 403 /core/templates/403.php;
-              error_page 404 /core/templates/404.php;
-              client_max_body_size ${cfg.maxUploadSize};
-              fastcgi_buffers 64 4K;
-              fastcgi_hide_header X-Powered-By;
-              gzip on;
-              gzip_vary on;
-              gzip_comp_level 4;
-              gzip_min_length 256;
-              gzip_proxied expired no-cache no-store private no_last_modified no_etag auth;
-              gzip_types application/atom+xml application/javascript application/json application/ld+json application/manifest+json application/rss+xml application/vnd.geo+json application/vnd.ms-fontobject application/x-font-ttf application/x-web-app-manifest+json application/xhtml+xml application/xml font/opentype image/bmp image/svg+xml image/x-icon text/cache-manifest text/css text/plain text/vcard text/vnd.rim.location.xloc text/vtt text/x-component text/x-cross-domain-policy;
-
-              ${optionalString cfg.webfinger ''
-                rewrite ^/.well-known/host-meta /public.php?service=host-meta last;
-                rewrite ^/.well-known/host-meta.json /public.php?service=host-meta-json last;
-              ''}
+              include ${config.services.nginx.package}/conf/fastcgi.conf;
+              fastcgi_split_path_info ^(.+?\.php)(\\/.*)$;
+              set $path_info $fastcgi_path_info;
+              try_files $fastcgi_script_name =404;
+              fastcgi_param PATH_INFO $path_info;
+              fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
+              fastcgi_param HTTPS ${if cfg.https then "on" else "off"};
+              fastcgi_param modHeadersAvailable true;
+              fastcgi_param front_controller_active true;
+              fastcgi_pass unix:${fpm.socket};
+              fastcgi_intercept_errors on;
+              fastcgi_request_buffering off;
+              fastcgi_read_timeout 120s;
             '';
           };
+          "~ \\.(?:css|js|svg|gif|map)$".extraConfig = ''
+            try_files $uri /index.php$request_uri;
+            expires 6M;
+            access_log off;
+          '';
+          "~ \\.woff2?$".extraConfig = ''
+            try_files $uri /index.php$request_uri;
+            expires 7d;
+            access_log off;
+          '';
+          "~ ^\\/(?:updater|ocs-provider|ocm-provider)(?:$|\\/)".extraConfig = ''
+            try_files $uri/ =404;
+            index index.php;
+          '';
         };
+        extraConfig = ''
+          index index.php index.html /index.php$request_uri;
+          expires 1m;
+          add_header X-Content-Type-Options nosniff;
+          add_header X-XSS-Protection "1; mode=block";
+          add_header X-Robots-Tag none;
+          add_header X-Download-Options noopen;
+          add_header X-Permitted-Cross-Domain-Policies none;
+          add_header X-Frame-Options sameorigin;
+          add_header Referrer-Policy no-referrer;
+          add_header Strict-Transport-Security "max-age=15552000; includeSubDomains" always;
+          client_max_body_size ${cfg.maxUploadSize};
+          fastcgi_buffers 64 4K;
+          fastcgi_hide_header X-Powered-By;
+          gzip on;
+          gzip_vary on;
+          gzip_comp_level 4;
+          gzip_min_length 256;
+          gzip_proxied expired no-cache no-store private no_last_modified no_etag auth;
+          gzip_types application/atom+xml application/javascript application/json application/ld+json application/manifest+json application/rss+xml application/vnd.geo+json application/vnd.ms-fontobject application/x-font-ttf application/x-web-app-manifest+json application/xhtml+xml application/xml font/opentype image/bmp image/svg+xml image/x-icon text/cache-manifest text/css text/plain text/vcard text/vnd.rim.location.xloc text/vtt text/x-component text/x-cross-domain-policy;
+
+          ${optionalString cfg.webfinger ''
+            rewrite ^/.well-known/host-meta /public.php?service=host-meta last;
+            rewrite ^/.well-known/host-meta.json /public.php?service=host-meta-json last;
+          ''}
+        '';
       };
-    })
+    }
   ]);
 
   meta.doc = ./nextcloud.xml;
diff --git a/nixos/modules/services/web-apps/nextcloud.xml b/nixos/modules/services/web-apps/nextcloud.xml
index fc454f8ba2549..02e4dba286108 100644
--- a/nixos/modules/services/web-apps/nextcloud.xml
+++ b/nixos/modules/services/web-apps/nextcloud.xml
@@ -29,7 +29,6 @@
   services.nextcloud = {
     <link linkend="opt-services.nextcloud.enable">enable</link> = true;
     <link linkend="opt-services.nextcloud.hostName">hostName</link> = "nextcloud.tld";
-    <link linkend="opt-services.nextcloud.nginx.enable">nginx.enable</link> = true;
     config = {
       <link linkend="opt-services.nextcloud.config.dbtype">dbtype</link> = "pgsql";
       <link linkend="opt-services.nextcloud.config.dbuser">dbuser</link> = "nextcloud";
@@ -61,9 +60,8 @@
   </para>
 
   <para>
-   The options <literal>hostName</literal> and <literal>nginx.enable</literal>
-   are used internally to configure an HTTP server using
-   <literal><link xlink:href="https://php-fpm.org/">PHP-FPM</link></literal>
+   The <literal>hostName</literal> option is used internally to configure an HTTP
+   server using <literal><link xlink:href="https://php-fpm.org/">PHP-FPM</link></literal>
    and <literal>nginx</literal>. The <literal>config</literal> attribute set is
    used by the imperative installer and all values are written to an additional file
    to ensure that changes can be applied by changing the module's options.
@@ -125,6 +123,61 @@
   </para>
  </section>
 
+ <section xml:id="module-services-nextcloud-httpd">
+  <title>Using an alternative webserver as reverse-proxy (e.g. <literal>httpd</literal>)</title>
+  <para>
+   By default, <package>nginx</package> is used as reverse-proxy for <package>nextcloud</package>.
+   However, it's possible to use e.g. <package>httpd</package> by explicitly disabling
+   <package>nginx</package> using <xref linkend="opt-services.nginx.enable" /> and fixing the
+   settings <literal>listen.owner</literal> &amp; <literal>listen.group</literal> in the
+   <link linkend="opt-services.phpfpm.pools">corresponding <literal>phpfpm</literal> pool</link>.
+  </para>
+  <para>
+   An exemplary configuration may look like this:
+<programlisting>{ config, lib, pkgs, ... }: {
+  <link linkend="opt-services.nginx.enable">services.nginx.enable</link> = false;
+  services.nextcloud = {
+    <link linkend="opt-services.nextcloud.enable">enable</link> = true;
+    <link linkend="opt-services.nextcloud.hostName">hostName</link> = "localhost";
+
+    /* further, required options */
+  };
+  <link linkend="opt-services.phpfpm.pools._name_.settings">services.phpfpm.pools.nextcloud.settings</link> = {
+    "listen.owner" = config.services.httpd.user;
+    "listen.group" = config.services.httpd.group;
+  };
+  services.httpd = {
+    <link linkend="opt-services.httpd.enable">enable</link> = true;
+    <link linkend="opt-services.httpd.adminAddr">adminAddr</link> = "webmaster@localhost";
+    <link linkend="opt-services.httpd.extraModules">extraModules</link> = [ "proxy_fcgi" ];
+    virtualHosts."localhost" = {
+      <link linkend="opt-services.httpd.virtualHosts._name_.documentRoot">documentRoot</link> = config.services.nextcloud.package;
+      <link linkend="opt-services.httpd.virtualHosts._name_.extraConfig">extraConfig</link> = ''
+        &lt;Directory "${config.services.nextcloud.package}"&gt;
+          &lt;FilesMatch "\.php$"&gt;
+            &lt;If "-f %{REQUEST_FILENAME}"&gt;
+              SetHandler "proxy:unix:${config.services.phpfpm.pools.nextcloud.socket}|fcgi://localhost/"
+            &lt;/If&gt;
+          &lt;/FilesMatch&gt;
+          &lt;IfModule mod_rewrite.c&gt;
+            RewriteEngine On
+            RewriteBase /
+            RewriteRule ^index\.php$ - [L]
+            RewriteCond %{REQUEST_FILENAME} !-f
+            RewriteCond %{REQUEST_FILENAME} !-d
+            RewriteRule . /index.php [L]
+          &lt;/IfModule&gt;
+          DirectoryIndex index.php
+          Require all granted
+          Options +FollowSymLinks
+        &lt;/Directory&gt;
+      '';
+    };
+  };
+}</programlisting>
+  </para>
+ </section>
+
  <section xml:id="module-services-nextcloud-maintainer-info">
   <title>Maintainer information</title>
 
@@ -161,5 +214,11 @@
   };
 }</programlisting>
   </para>
+
+  <para>
+   Ideally we should make sure that it's possible to jump two NixOS versions forward:
+   i.e. the warnings and the logic in the module should guard a user to upgrade from a
+   Nextcloud on e.g. 19.09 to a Nextcloud on 20.09.
+  </para>
  </section>
 </chapter>
diff --git a/nixos/modules/services/web-apps/pgpkeyserver-lite.nix b/nixos/modules/services/web-apps/pgpkeyserver-lite.nix
index ad70ba70bbeff..838fd19ad2949 100644
--- a/nixos/modules/services/web-apps/pgpkeyserver-lite.nix
+++ b/nixos/modules/services/web-apps/pgpkeyserver-lite.nix
@@ -33,7 +33,7 @@ in
         description = "
           Which hostname to set the vHost to that is proxying to sks.
         ";
-      };     
+      };
 
       hkpAddress = mkOption {
         default = builtins.head sksCfg.hkpAddress;
diff --git a/nixos/modules/services/web-apps/rss-bridge.nix b/nixos/modules/services/web-apps/rss-bridge.nix
new file mode 100644
index 0000000000000..f1d5b7660f320
--- /dev/null
+++ b/nixos/modules/services/web-apps/rss-bridge.nix
@@ -0,0 +1,127 @@
+{ config, lib, pkgs, ... }:
+with lib;
+let
+  cfg = config.services.rss-bridge;
+
+  poolName = "rss-bridge";
+
+  whitelist = pkgs.writeText "rss-bridge_whitelist.txt"
+    (concatStringsSep "\n" cfg.whitelist);
+in
+{
+  options = {
+    services.rss-bridge = {
+      enable = mkEnableOption "rss-bridge";
+
+      user = mkOption {
+        type = types.str;
+        default = "nginx";
+        example = "nginx";
+        description = ''
+          User account under which both the service and the web-application run.
+        '';
+      };
+
+      group = mkOption {
+        type = types.str;
+        default = "nginx";
+        example = "nginx";
+        description = ''
+          Group under which the web-application run.
+        '';
+      };
+
+      pool = mkOption {
+        type = types.str;
+        default = poolName;
+        description = ''
+          Name of existing phpfpm pool that is used to run web-application.
+          If not specified a pool will be created automatically with
+          default values.
+        '';
+      };
+
+      dataDir = mkOption {
+        type = types.str;
+        default = "/var/lib/rss-bridge";
+        description = ''
+          Location in which cache directory will be created.
+          You can put <literal>config.ini.php</literal> in here.
+        '';
+      };
+
+      virtualHost = mkOption {
+        type = types.nullOr types.str;
+        default = "rss-bridge";
+        description = ''
+          Name of the nginx virtualhost to use and setup. If null, do not setup any virtualhost.
+        '';
+      };
+
+      whitelist = mkOption {
+        type = types.listOf types.str;
+        default = [];
+        example = options.literalExample ''
+          [
+            "Facebook"
+            "Instagram"
+            "Twitter"
+          ]
+        '';
+        description = ''
+          List of bridges to be whitelisted.
+          If the list is empty, rss-bridge will use whitelist.default.txt.
+          Use <literal>[ "*" ]</literal> to whitelist all.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    services.phpfpm.pools = mkIf (cfg.pool == poolName) {
+      ${poolName} = {
+        user = cfg.user;
+        settings = mapAttrs (name: mkDefault) {
+          "listen.owner" = cfg.user;
+          "listen.group" = cfg.user;
+          "listen.mode" = "0600";
+          "pm" = "dynamic";
+          "pm.max_children" = 75;
+          "pm.start_servers" = 10;
+          "pm.min_spare_servers" = 5;
+          "pm.max_spare_servers" = 20;
+          "pm.max_requests" = 500;
+          "catch_workers_output" = 1;
+        };
+      };
+    };
+    systemd.tmpfiles.rules = [
+      "d '${cfg.dataDir}/cache' 0750 ${cfg.user} ${cfg.group} - -"
+      (mkIf (cfg.whitelist != []) "L+ ${cfg.dataDir}/whitelist.txt - - - - ${whitelist}")
+      "z '${cfg.dataDir}/config.ini.php' 0750 ${cfg.user} ${cfg.group} - -"
+    ];
+
+    services.nginx = mkIf (cfg.virtualHost != null) {
+      enable = true;
+      virtualHosts = {
+        ${cfg.virtualHost} = {
+          root = "${pkgs.rss-bridge}";
+
+          locations."/" = {
+            tryFiles = "$uri /index.php$is_args$args";
+          };
+
+          locations."~ ^/index.php(/|$)" = {
+            extraConfig = ''
+              include ${pkgs.nginx}/conf/fastcgi_params;
+              fastcgi_split_path_info ^(.+\.php)(/.+)$;
+              fastcgi_pass unix:${config.services.phpfpm.pools.${cfg.pool}.socket};
+              fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
+              fastcgi_param RSSBRIDGE_DATA ${cfg.dataDir};
+            '';
+          };
+        };
+      };
+    };
+  };
+}
diff --git a/nixos/modules/services/web-apps/sogo.nix b/nixos/modules/services/web-apps/sogo.nix
index 5f30124dd68ae..4610bb96cb5e4 100644
--- a/nixos/modules/services/web-apps/sogo.nix
+++ b/nixos/modules/services/web-apps/sogo.nix
@@ -77,7 +77,6 @@ in {
         // Paths
         WOSendMail = "/run/wrappers/bin/sendmail";
         SOGoMailSpoolPath = "/var/lib/sogo/spool";
-        SOGoZipPath = "${pkgs.zip}/bin/zip";
         // Enable CSRF protection
         SOGoXSRFValidationEnabled = YES;
         // Remove dates from log (jornald does that)
diff --git a/nixos/modules/services/web-apps/trilium.nix b/nixos/modules/services/web-apps/trilium.nix
index 6f47193c62b9d..3fa8dad049083 100644
--- a/nixos/modules/services/web-apps/trilium.nix
+++ b/nixos/modules/services/web-apps/trilium.nix
@@ -83,7 +83,7 @@ in
     };
   };
 
-  config = lib.mkIf cfg.enable (lib.mkMerge [ 
+  config = lib.mkIf cfg.enable (lib.mkMerge [
   {
     meta.maintainers = with lib.maintainers; [ kampka ];
 
diff --git a/nixos/modules/services/web-apps/tt-rss.nix b/nixos/modules/services/web-apps/tt-rss.nix
index 2ea9537b93de0..6a29f10d11954 100644
--- a/nixos/modules/services/web-apps/tt-rss.nix
+++ b/nixos/modules/services/web-apps/tt-rss.nix
@@ -632,8 +632,6 @@ let
           User = "${cfg.user}";
           Group = "tt_rss";
           ExecStart = "${pkgs.php}/bin/php ${cfg.root}/update.php --daemon --quiet";
-          StandardOutput = "syslog";
-          StandardError = "syslog";
           Restart = "on-failure";
           RestartSec = "60";
           SyslogIdentifier = "tt-rss";
diff --git a/nixos/modules/services/web-servers/apache-httpd/default.nix b/nixos/modules/services/web-servers/apache-httpd/default.nix
index 8abee7130d7c7..6dd1c85132c91 100644
--- a/nixos/modules/services/web-servers/apache-httpd/default.nix
+++ b/nixos/modules/services/web-servers/apache-httpd/default.nix
@@ -6,10 +6,18 @@ let
 
   cfg = config.services.httpd;
 
+  certs = config.security.acme.certs;
+
   runtimeDir = "/run/httpd";
 
   pkg = cfg.package.out;
 
+  apachectl = pkgs.runCommand "apachectl" { meta.priority = -1; } ''
+    mkdir -p $out/bin
+    cp ${pkg}/bin/apachectl $out/bin/apachectl
+    sed -i $out/bin/apachectl -e 's|$HTTPD -t|$HTTPD -t -f ${httpdConf}|'
+  '';
+
   httpdConf = cfg.configFile;
 
   php = cfg.phpPackage.override { apacheHttpd = pkg; };
@@ -20,6 +28,13 @@ let
 
   vhosts = attrValues cfg.virtualHosts;
 
+  # certName is used later on to determine systemd service names.
+  acmeEnabledVhosts = map (hostOpts: hostOpts // {
+    certName = if hostOpts.useACMEHost != null then hostOpts.useACMEHost else hostOpts.hostName;
+  }) (filter (hostOpts: hostOpts.enableACME || hostOpts.useACMEHost != null) vhosts);
+
+  dependentCertNames = unique (map (hostOpts: hostOpts.certName) acmeEnabledVhosts);
+
   mkListenInfo = hostOpts:
     if hostOpts.listen != [] then hostOpts.listen
     else (
@@ -119,13 +134,13 @@ let
 
       useACME = hostOpts.enableACME || hostOpts.useACMEHost != null;
       sslCertDir =
-        if hostOpts.enableACME then config.security.acme.certs.${hostOpts.hostName}.directory
-        else if hostOpts.useACMEHost != null then config.security.acme.certs.${hostOpts.useACMEHost}.directory
+        if hostOpts.enableACME then certs.${hostOpts.hostName}.directory
+        else if hostOpts.useACMEHost != null then certs.${hostOpts.useACMEHost}.directory
         else abort "This case should never happen.";
 
-      sslServerCert = if useACME then "${sslCertDir}/full.pem" else hostOpts.sslServerCert;
+      sslServerCert = if useACME then "${sslCertDir}/fullchain.pem" else hostOpts.sslServerCert;
       sslServerKey = if useACME then "${sslCertDir}/key.pem" else hostOpts.sslServerKey;
-      sslServerChain = if useACME then "${sslCertDir}/fullchain.pem" else hostOpts.sslServerChain;
+      sslServerChain = if useACME then "${sslCertDir}/chain.pem" else hostOpts.sslServerChain;
 
       acmeChallenge = optionalString useACME ''
         Alias /.well-known/acme-challenge/ "${hostOpts.acmeRoot}/.well-known/acme-challenge/"
@@ -341,7 +356,6 @@ let
       cat ${php.phpIni} > $out
       echo "$options" >> $out
     '';
-
 in
 
 
@@ -641,19 +655,41 @@ in
       wwwrun.gid = config.ids.gids.wwwrun;
     };
 
-    security.acme.certs = mapAttrs (name: hostOpts: {
-      user = cfg.user;
-      group = mkDefault cfg.group;
-      email = if hostOpts.adminAddr != null then hostOpts.adminAddr else cfg.adminAddr;
-      webroot = hostOpts.acmeRoot;
-      extraDomains = genAttrs hostOpts.serverAliases (alias: null);
-      postRun = "systemctl reload httpd.service";
-    }) (filterAttrs (name: hostOpts: hostOpts.enableACME) cfg.virtualHosts);
-
-    environment.systemPackages = [ pkg ];
+    security.acme.certs = let
+      acmePairs = map (hostOpts: nameValuePair hostOpts.hostName {
+        group = mkDefault cfg.group;
+        webroot = hostOpts.acmeRoot;
+        extraDomainNames = hostOpts.serverAliases;
+        # Use the vhost-specific email address if provided, otherwise let
+        # security.acme.email or security.acme.certs.<cert>.email be used.
+        email = mkOverride 2000 (if hostOpts.adminAddr != null then hostOpts.adminAddr else cfg.adminAddr);
+      # Filter for enableACME-only vhosts. Don't want to create dud certs
+      }) (filter (hostOpts: hostOpts.useACMEHost == null) acmeEnabledVhosts);
+    in listToAttrs acmePairs;
+
+    environment.systemPackages = [
+      apachectl
+      pkg
+    ];
 
-    # required for "apachectl configtest"
-    environment.etc."httpd/httpd.conf".source = httpdConf;
+    services.logrotate = optionalAttrs (cfg.logFormat != "none") {
+      enable = mkDefault true;
+      paths.httpd = {
+        path = "${cfg.logDir}/*.log";
+        user = cfg.user;
+        group = cfg.group;
+        frequency = "daily";
+        keep = 28;
+        extraConfig = ''
+          sharedscripts
+          compress
+          delaycompress
+          postrotate
+            systemctl reload httpd.service > /dev/null 2>/dev/null || true
+          endscript
+        '';
+      };
+    };
 
     services.httpd.phpOptions =
       ''
@@ -699,15 +735,12 @@ in
           "Z '${cfg.logDir}' - ${svc.User} ${svc.Group}"
         ];
 
-    systemd.services.httpd =
-      let
-        vhostsACME = filter (hostOpts: hostOpts.enableACME) vhosts;
-      in
-      { description = "Apache HTTPD";
-
+    systemd.services.httpd = {
+        description = "Apache HTTPD";
         wantedBy = [ "multi-user.target" ];
-        wants = concatLists (map (hostOpts: [ "acme-${hostOpts.hostName}.service" "acme-selfsigned-${hostOpts.hostName}.service" ]) vhostsACME);
-        after = [ "network.target" "fs.target" ] ++ map (hostOpts: "acme-selfsigned-${hostOpts.hostName}.service") vhostsACME;
+        wants = concatLists (map (certName: [ "acme-finished-${certName}.target" ]) dependentCertNames);
+        after = [ "network.target" ] ++ map (certName: "acme-selfsigned-${certName}.service") dependentCertNames;
+        before = map (certName: "acme-${certName}.service") dependentCertNames;
 
         path = [ pkg pkgs.coreutils pkgs.gnugrep ];
 
@@ -741,5 +774,31 @@ in
         };
       };
 
+    # postRun hooks on cert renew can't be used to restart Apache since renewal
+    # runs as the unprivileged acme user. sslTargets are added to wantedBy + before
+    # which allows the acme-finished-$cert.target to signify the successful updating
+    # of certs end-to-end.
+    systemd.services.httpd-config-reload = let
+      sslServices = map (certName: "acme-${certName}.service") dependentCertNames;
+      sslTargets = map (certName: "acme-finished-${certName}.target") dependentCertNames;
+    in mkIf (sslServices != []) {
+      wantedBy = sslServices ++ [ "multi-user.target" ];
+      # Before the finished targets, after the renew services.
+      # This service might be needed for HTTP-01 challenges, but we only want to confirm
+      # certs are updated _after_ config has been reloaded.
+      before = sslTargets;
+      after = sslServices;
+      # Block reloading if not all certs exist yet.
+      # Happens when config changes add new vhosts/certs.
+      unitConfig.ConditionPathExists = map (certName: certs.${certName}.directory + "/fullchain.pem") dependentCertNames;
+      serviceConfig = {
+        Type = "oneshot";
+        TimeoutSec = 60;
+        ExecCondition = "/run/current-system/systemd/bin/systemctl -q is-active httpd.service";
+        ExecStartPre = "${pkg}/bin/httpd -f ${httpdConf} -t";
+        ExecStart = "/run/current-system/systemd/bin/systemctl reload httpd.service";
+      };
+    };
+
   };
 }
diff --git a/nixos/modules/services/web-servers/caddy.nix b/nixos/modules/services/web-servers/caddy.nix
index 0e6e10a5f47d9..dda26fe491a1f 100644
--- a/nixos/modules/services/web-servers/caddy.nix
+++ b/nixos/modules/services/web-servers/caddy.nix
@@ -5,6 +5,26 @@ with lib;
 let
   cfg = config.services.caddy;
   configFile = pkgs.writeText "Caddyfile" cfg.config;
+
+  # v2-specific options
+  isCaddy2 = versionAtLeast cfg.package.version "2.0";
+  tlsConfig = {
+    apps.tls.automation.policies = [{
+      issuer = {
+        inherit (cfg) ca email;
+        module = "acme";
+      };
+    }];
+  };
+
+  adaptedConfig = pkgs.runCommand "caddy-config-adapted.json" { } ''
+    ${cfg.package}/bin/caddy adapt \
+      --config ${configFile} --adapter ${cfg.adapter} > $out
+  '';
+  tlsJSON = pkgs.writeText "tls.json" (builtins.toJSON tlsConfig);
+  configJSON = pkgs.runCommand "caddy-config.json" { } ''
+    ${pkgs.jq}/bin/jq -s '.[0] * .[1]' ${adaptedConfig} ${tlsJSON} > $out
+  '';
 in {
   options.services.caddy = {
     enable = mkEnableOption "Caddy web server";
@@ -13,15 +33,26 @@ in {
       default = "";
       example = ''
         example.com {
-        gzip
-        minify
-        log syslog
-
-        root /srv/http
+          encode gzip
+          log
+          root /srv/http
         }
       '';
       type = types.lines;
-      description = "Verbatim Caddyfile to use";
+      description = ''
+        Verbatim Caddyfile to use.
+        Caddy v2 supports multiple config formats via adapters (see <option>services.caddy.adapter</option>).
+      '';
+    };
+
+    adapter = mkOption {
+      default = "caddyfile";
+      example = "nginx";
+      type = types.str;
+      description = ''
+        Name of the config adapter to use. Not applicable to Caddy v1.
+        See https://caddyserver.com/docs/config-adapters for the full list.
+      '';
     };
 
     ca = mkOption {
@@ -50,33 +81,46 @@ in {
         The data directory, for storing certificates. Before 17.09, this
         would create a .caddy directory. With 17.09 the contents of the
         .caddy directory are in the specified data directory instead.
+
+        Caddy v2 replaced CADDYPATH with XDG directories.
+        See https://caddyserver.com/docs/conventions#file-locations.
       '';
     };
 
     package = mkOption {
       default = pkgs.caddy;
       defaultText = "pkgs.caddy";
+      example = "pkgs.caddy1";
       type = types.package;
-      description = "Caddy package to use.";
+      description = ''
+        Caddy package to use.
+        To use Caddy v1 (obsolete), set this to <literal>pkgs.caddy1</literal>.
+      '';
     };
   };
 
   config = mkIf cfg.enable {
     systemd.services.caddy = {
       description = "Caddy web server";
-      # upstream unit: https://github.com/caddyserver/caddy/blob/master/dist/init/linux-systemd/caddy.service
+      # upstream unit: https://github.com/caddyserver/dist/blob/master/init/caddy.service
       after = [ "network-online.target" ];
       wants = [ "network-online.target" ]; # systemd-networkd-wait-online.service
       wantedBy = [ "multi-user.target" ];
-      environment = mkIf (versionAtLeast config.system.stateVersion "17.09")
+      environment = mkIf (versionAtLeast config.system.stateVersion "17.09" && !isCaddy2)
         { CADDYPATH = cfg.dataDir; };
       serviceConfig = {
-        ExecStart = ''
+        ExecStart = if isCaddy2 then ''
+          ${cfg.package}/bin/caddy run --config ${configJSON}
+        '' else ''
           ${cfg.package}/bin/caddy -log stdout -log-timestamps=false \
             -root=/var/tmp -conf=${configFile} \
             -ca=${cfg.ca} -email=${cfg.email} ${optionalString cfg.agree "-agree"}
         '';
-        ExecReload = "${pkgs.coreutils}/bin/kill -USR1 $MAINPID";
+        ExecReload =
+          if isCaddy2 then
+            "${cfg.package}/bin/caddy reload --config ${configJSON}"
+          else
+            "${pkgs.coreutils}/bin/kill -USR1 $MAINPID";
         Type = "simple";
         User = "caddy";
         Group = "caddy";
diff --git a/nixos/modules/services/web-servers/jboss/builder.sh b/nixos/modules/services/web-servers/jboss/builder.sh
index 2eb89a90f67d5..0e5af324c13fe 100644
--- a/nixos/modules/services/web-servers/jboss/builder.sh
+++ b/nixos/modules/services/web-servers/jboss/builder.sh
@@ -28,11 +28,11 @@ stop()
 if test "\$1" = start
 then
   trap stop 15
-  
+
   start
 elif test "\$1" = stop
 then
-  stop  
+  stop
 elif test "\$1" = init
 then
   echo "Are you sure you want to create a new server instance (old server instance will be lost!)?"
@@ -42,21 +42,21 @@ then
   then
     exit 1
   fi
-  
+
   rm -rf $serverDir
   mkdir -p $serverDir
   cd $serverDir
   cp -av $jboss/server/default .
   sed -i -e "s|deploy/|$deployDir|" default/conf/jboss-service.xml
-  
+
   if ! test "$useJK" = ""
   then
     sed -i -e 's|<attribute name="UseJK">false</attribute>|<attribute name="UseJK">true</attribute>|' default/deploy/jboss-web.deployer/META-INF/jboss-service.xml
     sed -i -e 's|<Engine name="jboss.web" defaultHost="localhost">|<Engine name="jboss.web" defaultHost="localhost" jvmRoute="node1">|' default/deploy/jboss-web.deployer/server.xml
   fi
-  
+
   # Make files accessible for the server user
-  
+
   chown -R $user $serverDir
   for i in \`find $serverDir -type d\`
   do
diff --git a/nixos/modules/services/web-servers/meguca.nix b/nixos/modules/services/web-servers/meguca.nix
deleted file mode 100644
index 5a00070dc9416..0000000000000
--- a/nixos/modules/services/web-servers/meguca.nix
+++ /dev/null
@@ -1,174 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-let
-  cfg = config.services.meguca;
-  postgres = config.services.postgresql;
-in with lib; {
-  options.services.meguca = {
-    enable = mkEnableOption "meguca";
-
-    dataDir = mkOption {
-      type = types.path;
-      default = "/var/lib/meguca";
-      example = "/home/okina/meguca";
-      description = "Location where meguca stores it's database and links.";
-    };
-
-    password = mkOption {
-      type = types.str;
-      default = "meguca";
-      example = "dumbpass";
-      description = "Password for the meguca database.";
-    };
-
-    passwordFile = mkOption {
-      type = types.path;
-      default = "/run/keys/meguca-password-file";
-      example = "/home/okina/meguca/keys/pass";
-      description = "Password file for the meguca database.";
-    };
-
-    reverseProxy = mkOption {
-      type = types.nullOr types.str;
-      default = null;
-      example = "192.168.1.5";
-      description = "Reverse proxy IP.";
-    };
-
-    sslCertificate = mkOption {
-      type = types.nullOr types.str;
-      default = null;
-      example = "/home/okina/meguca/ssl.cert";
-      description = "Path to the SSL certificate.";
-    };
-
-    listenAddress = mkOption {
-      type = types.nullOr types.str;
-      default = null;
-      example = "127.0.0.1:8000";
-      description = "Listen on a specific IP address and port.";
-    };
-
-    cacheSize = mkOption {
-      type = types.nullOr types.int;
-      default = null;
-      example = 256;
-      description = "Cache size in MB.";
-    };
-
-    postgresArgs = mkOption {
-      type = types.str;
-      example = "user=meguca password=dumbpass dbname=meguca sslmode=disable";
-      description = "Postgresql connection arguments.";
-    };
-
-    postgresArgsFile = mkOption {
-      type = types.path;
-      default = "/run/keys/meguca-postgres-args";
-      example = "/home/okina/meguca/keys/postgres";
-      description = "Postgresql connection arguments file.";
-    };
-
-    compressTraffic = mkOption {
-      type = types.bool;
-      default = false;
-      description = "Compress all traffic with gzip.";
-    };
-
-    assumeReverseProxy = mkOption {
-      type = types.bool;
-      default = false;
-      description = "Assume the server is behind a reverse proxy, when resolving client IPs.";
-    };
-
-    httpsOnly = mkOption {
-      type = types.bool;
-      default = false;
-      description = "Serve and listen only through HTTPS.";
-    };
-
-    videoPaths = mkOption {
-      type = types.listOf types.path;
-      default = [];
-      example = [ "/home/okina/Videos/tehe_pero.webm" ];
-      description = "Videos that will be symlinked into www/videos.";
-    };
-  };
-
-  config = mkIf cfg.enable {
-    security.sudo.enable = cfg.enable;
-    services.postgresql.enable = cfg.enable;
-    services.postgresql.package = pkgs.postgresql_11;
-    services.meguca.passwordFile = mkDefault (pkgs.writeText "meguca-password-file" cfg.password);
-    services.meguca.postgresArgsFile = mkDefault (pkgs.writeText "meguca-postgres-args" cfg.postgresArgs);
-    services.meguca.postgresArgs = mkDefault "user=meguca password=${cfg.password} dbname=meguca sslmode=disable";
-
-    systemd.services.meguca = {
-      description = "meguca";
-      after = [ "network.target" "postgresql.service" ];
-      wantedBy = [ "multi-user.target" ];
-
-      preStart = ''
-        # Ensure folder exists or create it and links and permissions are correct
-        mkdir -p ${escapeShellArg cfg.dataDir}/www
-        rm -rf ${escapeShellArg cfg.dataDir}/www/videos
-        ln -sf ${pkgs.meguca}/share/meguca/www/* ${escapeShellArg cfg.dataDir}/www
-        unlink ${escapeShellArg cfg.dataDir}/www/videos
-        mkdir -p ${escapeShellArg cfg.dataDir}/www/videos
-
-        for vid in ${escapeShellArg cfg.videoPaths}; do
-          ln -sf $vid ${escapeShellArg cfg.dataDir}/www/videos
-        done
-
-        chmod 750 ${escapeShellArg cfg.dataDir}
-        chown -R meguca:meguca ${escapeShellArg cfg.dataDir}
-
-        # Ensure the database is correct or create it
-        ${pkgs.sudo}/bin/sudo -u ${postgres.superUser} ${postgres.package}/bin/createuser \
-          -SDR meguca || true
-        ${pkgs.sudo}/bin/sudo -u ${postgres.superUser} ${postgres.package}/bin/createdb \
-          -T template0 -E UTF8 -O meguca meguca || true
-        ${pkgs.sudo}/bin/sudo -u meguca ${postgres.package}/bin/psql \
-          -c "ALTER ROLE meguca WITH PASSWORD '$(cat ${escapeShellArg cfg.passwordFile})';" || true
-      '';
-
-    script = ''
-      cd ${escapeShellArg cfg.dataDir}
-
-      ${pkgs.meguca}/bin/meguca -d "$(cat ${escapeShellArg cfg.postgresArgsFile})"''
-      + optionalString (cfg.reverseProxy != null) " -R ${cfg.reverseProxy}"
-      + optionalString (cfg.sslCertificate != null) " -S ${cfg.sslCertificate}"
-      + optionalString (cfg.listenAddress != null) " -a ${cfg.listenAddress}"
-      + optionalString (cfg.cacheSize != null) " -c ${toString cfg.cacheSize}"
-      + optionalString (cfg.compressTraffic) " -g"
-      + optionalString (cfg.assumeReverseProxy) " -r"
-      + optionalString (cfg.httpsOnly) " -s" + " start";
-
-      serviceConfig = {
-        PermissionsStartOnly = true;
-        Type = "forking";
-        User = "meguca";
-        Group = "meguca";
-        ExecStop = "${pkgs.meguca}/bin/meguca stop";
-      };
-    };
-
-    users = {
-      groups.meguca.gid = config.ids.gids.meguca;
-
-      users.meguca = {
-        description = "meguca server service user";
-        home = cfg.dataDir;
-        createHome = true;
-        group = "meguca";
-        uid = config.ids.uids.meguca;
-      };
-    };
-  };
-
-  imports = [
-    (mkRenamedOptionModule [ "services" "meguca" "baseDir" ] [ "services" "meguca" "dataDir" ])
-  ];
-
-  meta.maintainers = with maintainers; [ chiiruno ];
-}
diff --git a/nixos/modules/services/web-servers/molly-brown.nix b/nixos/modules/services/web-servers/molly-brown.nix
new file mode 100644
index 0000000000000..e9052a184b2db
--- /dev/null
+++ b/nixos/modules/services/web-servers/molly-brown.nix
@@ -0,0 +1,117 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.molly-brown;
+
+  settingsType = with types;
+    attrsOf (oneOf [
+      int
+      str
+      (listOf str)
+      (attrsOf (oneOf [ int str (listOf str) (attrsOf str) ]))
+    ]) // {
+      description = "primitive expression convertable to TOML";
+    };
+
+  configFile = pkgs.runCommand "molly-brown.toml" {
+    buildInputs = [ pkgs.remarshal ];
+    preferLocalBuild = true;
+    passAsFile = [ "settings" ];
+    settings = builtins.toJSON cfg.settings;
+  } "remarshal -if json -of toml < $settingsPath > $out";
+in {
+
+  options.services.molly-brown = {
+
+    enable = mkEnableOption "Molly-Brown Gemini server";
+
+    port = mkOption {
+      default = 1965;
+      type = types.port;
+      description = ''
+        TCP port for molly-brown to bind to.
+      '';
+    };
+
+    hostName = mkOption {
+      type = types.str;
+      example = literalExample "config.networking.hostName";
+      default = config.networking.hostName;
+      description = ''
+        The hostname to respond to requests for. Requests for URLs with
+        other hosts will result in a status 53 (PROXY REQUEST REFUSED)
+        response.
+      '';
+    };
+
+    certPath = mkOption {
+      type = types.path;
+      example = "/var/lib/acme/example.com/cert.pem";
+      description = ''
+        Path to TLS certificate. An ACME certificate and key may be
+        shared with an HTTP server, but only if molly-brown has
+        permissions allowing it to read such keys.
+
+        As an example:
+        <programlisting>
+        security.acme.certs."example.com".allowKeysForGroup = true;
+        systemd.services.molly-brown.serviceConfig.SupplementaryGroups =
+          [ config.security.acme.certs."example.com".group ];
+        </programlisting>
+      '';
+    };
+
+    keyPath = mkOption {
+      type = types.path;
+      example = "/var/lib/acme/example.com/key.pem";
+      description = "Path to TLS key. See <option>CertPath</option>.";
+    };
+
+    docBase = mkOption {
+      type = types.path;
+      example = "/var/lib/molly-brown";
+      description = "Base directory for Gemini content.";
+    };
+
+    settings = mkOption {
+      type = settingsType;
+      default = { };
+      description = ''
+        molly-brown configuration. Refer to
+        <link xlink:href="https://tildegit.org/solderpunk/molly-brown/src/branch/master/example.conf"/>
+        for details on supported values.
+      '';
+    };
+
+  };
+
+  config = mkIf cfg.enable {
+
+    services.molly-brown.settings = let logDir = "/var/log/molly-brown";
+    in {
+      Port = cfg.port;
+      Hostname = cfg.hostName;
+      CertPath = cfg.certPath;
+      KeyPath = cfg.keyPath;
+      DocBase = cfg.docBase;
+      AccessLog = "${logDir}/access.log";
+      ErrorLog = "${logDir}/error.log";
+    };
+
+    systemd.services.molly-brown = {
+      description = "Molly Brown gemini server";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      serviceConfig = {
+        DynamicUser = true;
+        LogsDirectory = "molly-brown";
+        ExecStart = "${pkgs.molly-brown}/bin/molly-brown -c ${configFile}";
+        Restart = "always";
+      };
+    };
+
+  };
+
+}
diff --git a/nixos/modules/services/web-servers/nginx/default.nix b/nixos/modules/services/web-servers/nginx/default.nix
index 8a015bb3556c1..39bcb14e5afe8 100644
--- a/nixos/modules/services/web-servers/nginx/default.nix
+++ b/nixos/modules/services/web-servers/nginx/default.nix
@@ -6,23 +6,23 @@ let
   cfg = config.services.nginx;
   certs = config.security.acme.certs;
   vhostsConfigs = mapAttrsToList (vhostName: vhostConfig: vhostConfig) virtualHosts;
-  acmeEnabledVhosts = filter (vhostConfig: vhostConfig.enableACME && vhostConfig.useACMEHost == null) vhostsConfigs;
+  acmeEnabledVhosts = filter (vhostConfig: vhostConfig.enableACME || vhostConfig.useACMEHost != null) vhostsConfigs;
+  dependentCertNames = unique (map (hostOpts: hostOpts.certName) acmeEnabledVhosts);
   virtualHosts = mapAttrs (vhostName: vhostConfig:
     let
       serverName = if vhostConfig.serverName != null
         then vhostConfig.serverName
         else vhostName;
+      certName = if vhostConfig.useACMEHost != null
+        then vhostConfig.useACMEHost
+        else serverName;
     in
     vhostConfig // {
-      inherit serverName;
-    } // (optionalAttrs vhostConfig.enableACME {
-      sslCertificate = "${certs.${serverName}.directory}/fullchain.pem";
-      sslCertificateKey = "${certs.${serverName}.directory}/key.pem";
-      sslTrustedCertificate = "${certs.${serverName}.directory}/full.pem";
-    }) // (optionalAttrs (vhostConfig.useACMEHost != null) {
-      sslCertificate = "${certs.${vhostConfig.useACMEHost}.directory}/fullchain.pem";
-      sslCertificateKey = "${certs.${vhostConfig.useACMEHost}.directory}/key.pem";
-      sslTrustedCertificate = "${certs.${vhostConfig.useACMEHost}.directory}/fullchain.pem";
+      inherit serverName certName;
+    } // (optionalAttrs (vhostConfig.enableACME || vhostConfig.useACMEHost != null) {
+      sslCertificate = "${certs.${certName}.directory}/fullchain.pem";
+      sslCertificateKey = "${certs.${certName}.directory}/key.pem";
+      sslTrustedCertificate = "${certs.${certName}.directory}/chain.pem";
     })
   ) cfg.virtualHosts;
   enableIPv6 = config.networking.enableIPv6;
@@ -463,14 +463,6 @@ in
         '';
       };
 
-      enableSandbox = mkOption {
-        default = false;
-        type = types.bool;
-        description = ''
-          Starting Nginx web server with additional sandbox/hardening options.
-        '';
-      };
-
       user = mkOption {
         type = types.str;
         default = "nginx";
@@ -691,8 +683,12 @@ in
     systemd.services.nginx = {
       description = "Nginx Web Server";
       wantedBy = [ "multi-user.target" ];
-      wants = concatLists (map (vhostConfig: ["acme-${vhostConfig.serverName}.service" "acme-selfsigned-${vhostConfig.serverName}.service"]) acmeEnabledVhosts);
-      after = [ "network.target" ] ++ map (vhostConfig: "acme-selfsigned-${vhostConfig.serverName}.service") acmeEnabledVhosts;
+      wants = concatLists (map (certName: [ "acme-finished-${certName}.target" ]) dependentCertNames);
+      after = [ "network.target" ] ++ map (certName: "acme-selfsigned-${certName}.service") dependentCertNames;
+      # Nginx needs to be started in order to be able to request certificates
+      # (it's hosting the acme challenge after all)
+      # This fixes https://github.com/NixOS/nixpkgs/issues/81842
+      before = map (certName: "acme-${certName}.service") dependentCertNames;
       stopIfChanged = false;
       preStart = ''
         ${cfg.preStart}
@@ -700,7 +696,10 @@ in
       '';
       serviceConfig = {
         ExecStart = execCommand;
-        ExecReload = "${pkgs.coreutils}/bin/kill -HUP $MAINPID";
+        ExecReload = [
+          "${execCommand} -t"
+          "${pkgs.coreutils}/bin/kill -HUP $MAINPID"
+        ];
         Restart = "always";
         RestartSec = "10s";
         StartLimitInterval = "1min";
@@ -721,7 +720,6 @@ in
         CapabilityBoundingSet = [ "CAP_NET_BIND_SERVICE" "CAP_SYS_RESOURCE" ];
         # Security
         NoNewPrivileges = true;
-      } // optionalAttrs cfg.enableSandbox {
         # Sandboxing
         ProtectSystem = "strict";
         ProtectHome = mkDefault true;
@@ -746,38 +744,41 @@ in
       source = configFile;
     };
 
-    systemd.services.nginx-config-reload = mkIf cfg.enableReload {
-      wants = [ "nginx.service" ];
-      wantedBy = [ "multi-user.target" ];
-      restartTriggers = [ configFile ];
-      # commented, because can cause extra delays during activate for this config:
-      #      services.nginx.virtualHosts."_".locations."/".proxyPass = "http://blabla:3000";
-      # stopIfChanged = false;
-      serviceConfig.Type = "oneshot";
-      serviceConfig.TimeoutSec = 60;
-      script = ''
-        if /run/current-system/systemd/bin/systemctl -q is-active nginx.service ; then
-          ${execCommand} -t && \
-            /run/current-system/systemd/bin/systemctl reload nginx.service
-        fi
-      '';
-      serviceConfig.RemainAfterExit = true;
+    # postRun hooks on cert renew can't be used to restart Nginx since renewal
+    # runs as the unprivileged acme user. sslTargets are added to wantedBy + before
+    # which allows the acme-finished-$cert.target to signify the successful updating
+    # of certs end-to-end.
+    systemd.services.nginx-config-reload = let
+      sslServices = map (certName: "acme-${certName}.service") dependentCertNames;
+      sslTargets = map (certName: "acme-finished-${certName}.target") dependentCertNames;
+    in mkIf (cfg.enableReload || sslServices != []) {
+      wants = optionals (cfg.enableReload) [ "nginx.service" ];
+      wantedBy = sslServices ++ [ "multi-user.target" ];
+      # Before the finished targets, after the renew services.
+      # This service might be needed for HTTP-01 challenges, but we only want to confirm
+      # certs are updated _after_ config has been reloaded.
+      before = sslTargets;
+      after = sslServices;
+      restartTriggers = optionals (cfg.enableReload) [ configFile ];
+      # Block reloading if not all certs exist yet.
+      # Happens when config changes add new vhosts/certs.
+      unitConfig.ConditionPathExists = optionals (sslServices != []) (map (certName: certs.${certName}.directory + "/fullchain.pem") dependentCertNames);
+      serviceConfig = {
+        Type = "oneshot";
+        TimeoutSec = 60;
+        ExecCondition = "/run/current-system/systemd/bin/systemctl -q is-active nginx.service";
+        ExecStart = "/run/current-system/systemd/bin/systemctl reload nginx.service";
+      };
     };
 
-    security.acme.certs = filterAttrs (n: v: v != {}) (
-      let
-        acmePairs = map (vhostConfig: { name = vhostConfig.serverName; value = {
-            user = cfg.user;
-            group = lib.mkDefault cfg.group;
-            webroot = vhostConfig.acmeRoot;
-            extraDomains = genAttrs vhostConfig.serverAliases (alias: null);
-            postRun = ''
-              /run/current-system/systemd/bin/systemctl reload nginx
-            '';
-          }; }) acmeEnabledVhosts;
-      in
-        listToAttrs acmePairs
-    );
+    security.acme.certs = let
+      acmePairs = map (vhostConfig: nameValuePair vhostConfig.serverName {
+        group = mkDefault cfg.group;
+        webroot = vhostConfig.acmeRoot;
+        extraDomainNames = vhostConfig.serverAliases;
+      # Filter for enableACME-only vhosts. Don't want to create dud certs
+      }) (filter (vhostConfig: vhostConfig.useACMEHost == null) acmeEnabledVhosts);
+    in listToAttrs acmePairs;
 
     users.users = optionalAttrs (cfg.user == "nginx") {
       nginx = {
diff --git a/nixos/modules/services/web-servers/phpfpm/default.nix b/nixos/modules/services/web-servers/phpfpm/default.nix
index d090885a8ca52..759eebf768db2 100644
--- a/nixos/modules/services/web-servers/phpfpm/default.nix
+++ b/nixos/modules/services/web-servers/phpfpm/default.nix
@@ -277,6 +277,7 @@ in {
           ExecReload = "${pkgs.coreutils}/bin/kill -USR2 $MAINPID";
           RuntimeDirectory = "phpfpm";
           RuntimeDirectoryPreserve = true; # Relevant when multiple processes are running
+          Restart = "always";
         };
       }
     ) cfg.pools;
diff --git a/nixos/modules/services/web-servers/shellinabox.nix b/nixos/modules/services/web-servers/shellinabox.nix
index 58a02ac59c358..c7c51f873eba8 100644
--- a/nixos/modules/services/web-servers/shellinabox.nix
+++ b/nixos/modules/services/web-servers/shellinabox.nix
@@ -51,7 +51,7 @@ in
           Whether or not to enable SSL (https) support.
         '';
       };
-        
+
       certDirectory = mkOption {
         type = types.nullOr types.path;
         default = null;
diff --git a/nixos/modules/services/web-servers/traefik.nix b/nixos/modules/services/web-servers/traefik.nix
index 0631a26569c8c..4ab7307c3b671 100644
--- a/nixos/modules/services/web-servers/traefik.nix
+++ b/nixos/modules/services/web-servers/traefik.nix
@@ -20,10 +20,10 @@ let
     in valueType;
   dynamicConfigFile = if cfg.dynamicConfigFile == null then
     pkgs.runCommand "config.toml" {
-      buildInputs = [ pkgs.yj ];
+      buildInputs = [ pkgs.remarshal ];
       preferLocalBuild = true;
     } ''
-      yj -jt -i \
+      remarshal -if json -of toml \
         < ${
           pkgs.writeText "dynamic_config.json"
           (builtins.toJSON cfg.dynamicConfigOptions)
diff --git a/nixos/modules/services/web-servers/unit/default.nix b/nixos/modules/services/web-servers/unit/default.nix
index 989866144e1ee..894271d1e55e4 100644
--- a/nixos/modules/services/web-servers/unit/default.nix
+++ b/nixos/modules/services/web-servers/unit/default.nix
@@ -102,7 +102,7 @@ in {
         PIDFile = "/run/unit/unit.pid";
         ExecStart = ''
           ${cfg.package}/bin/unitd --control 'unix:/run/unit/control.unit.sock' --pid '/run/unit/unit.pid' \
-                                   --log '${cfg.logDir}/unit.log' --state '${cfg.stateDir}' \
+                                   --log '${cfg.logDir}/unit.log' --state '${cfg.stateDir}' --tmp '/tmp' \
                                    --user ${cfg.user} --group ${cfg.group}
         '';
         ExecStop = ''
@@ -120,9 +120,12 @@ in {
         ProtectHome = true;
         PrivateTmp = true;
         PrivateDevices = true;
+        PrivateUsers = false;
         ProtectHostname = true;
+        ProtectClock = true;
         ProtectKernelTunables = true;
         ProtectKernelModules = true;
+        ProtectKernelLogs = true;
         ProtectControlGroups = true;
         RestrictAddressFamilies = [ "AF_UNIX" "AF_INET" "AF_INET6" ];
         LockPersonality = true;
diff --git a/nixos/modules/services/x11/colord.nix b/nixos/modules/services/x11/colord.nix
index cf113ad2af8c9..31ccee6aa33f4 100644
--- a/nixos/modules/services/x11/colord.nix
+++ b/nixos/modules/services/x11/colord.nix
@@ -26,7 +26,7 @@ in {
 
     systemd.packages = [ pkgs.colord ];
 
-    environment.etc."tmpfiles.d/colord.conf".source = "${pkgs.colord}/lib/tmpfiles.d/colord.conf";
+    systemd.tmpfiles.packages = [ pkgs.colord ];
 
     users.users.colord = {
       isSystemUser = true;
diff --git a/nixos/modules/services/x11/desktop-managers/cinnamon.nix b/nixos/modules/services/x11/desktop-managers/cinnamon.nix
new file mode 100644
index 0000000000000..a404143a03d4b
--- /dev/null
+++ b/nixos/modules/services/x11/desktop-managers/cinnamon.nix
@@ -0,0 +1,205 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.services.xserver.desktopManager.cinnamon;
+  serviceCfg = config.services.cinnamon;
+
+  nixos-gsettings-overrides = pkgs.cinnamon.cinnamon-gsettings-overrides.override {
+    extraGSettingsOverridePackages = cfg.extraGSettingsOverridePackages;
+    extraGSettingsOverrides = cfg.extraGSettingsOverrides;
+  };
+
+in
+
+{
+  options = {
+    services.cinnamon = {
+      apps.enable = mkEnableOption "Cinnamon default applications";
+    };
+
+    services.xserver.desktopManager.cinnamon = {
+      enable = mkEnableOption "the cinnamon desktop manager";
+
+      sessionPath = mkOption {
+        default = [];
+        example = literalExample "[ pkgs.gnome3.gpaste ]";
+        description = ''
+          Additional list of packages to be added to the session search path.
+          Useful for GSettings-conditional autostart.
+
+          Note that this should be a last resort; patching the package is preferred (see GPaste).
+        '';
+      };
+
+      extraGSettingsOverrides = mkOption {
+        default = "";
+        type = types.lines;
+        description = "Additional gsettings overrides.";
+      };
+
+      extraGSettingsOverridePackages = mkOption {
+        default = [];
+        type = types.listOf types.path;
+        description = "List of packages for which gsettings are overridden.";
+      };
+    };
+
+    environment.cinnamon.excludePackages = mkOption {
+      default = [];
+      example = literalExample "[ pkgs.cinnamon.blueberry ]";
+      type = types.listOf types.package;
+      description = "Which packages cinnamon should exclude from the default environment";
+    };
+
+  };
+
+  config = mkMerge [
+    (mkIf (cfg.enable && config.services.xserver.displayManager.lightdm.enable && config.services.xserver.displayManager.lightdm.greeters.gtk.enable) {
+      services.xserver.displayManager.lightdm.greeters.gtk.extraConfig = mkDefault (builtins.readFile "${pkgs.cinnamon.mint-artwork}/etc/lightdm/lightdm-gtk-greeter.conf.d/99_linuxmint.conf");
+      })
+
+    (mkIf cfg.enable {
+      services.xserver.displayManager.sessionPackages = [ pkgs.cinnamon.cinnamon-common ];
+
+      services.xserver.displayManager.sessionCommands = ''
+        if test "$XDG_CURRENT_DESKTOP" = "Cinnamon"; then
+            true
+            ${concatMapStrings (p: ''
+              if [ -d "${p}/share/gsettings-schemas/${p.name}" ]; then
+                export XDG_DATA_DIRS=$XDG_DATA_DIRS''${XDG_DATA_DIRS:+:}${p}/share/gsettings-schemas/${p.name}
+              fi
+
+              if [ -d "${p}/lib/girepository-1.0" ]; then
+                export GI_TYPELIB_PATH=$GI_TYPELIB_PATH''${GI_TYPELIB_PATH:+:}${p}/lib/girepository-1.0
+                export LD_LIBRARY_PATH=$LD_LIBRARY_PATH''${LD_LIBRARY_PATH:+:}${p}/lib
+              fi
+            '') cfg.sessionPath}
+        fi
+      '';
+
+      # Default services
+      hardware.bluetooth.enable = mkDefault true;
+      hardware.pulseaudio.enable = mkDefault true;
+      security.polkit.enable = true;
+      services.accounts-daemon.enable = true;
+      services.system-config-printer.enable = (mkIf config.services.printing.enable (mkDefault true));
+      services.dbus.packages = with pkgs.cinnamon; [
+        cinnamon-common
+        cinnamon-screensaver
+        nemo
+        xapps
+      ];
+      services.cinnamon.apps.enable = mkDefault true;
+      services.gnome3.glib-networking.enable = true;
+      services.gnome3.gnome-keyring.enable = true;
+      services.gvfs.enable = true;
+      services.udisks2.enable = true;
+      services.upower.enable = mkDefault config.powerManagement.enable;
+      services.xserver.libinput.enable = mkDefault true;
+      services.xserver.updateDbusEnvironment = true;
+      networking.networkmanager.enable = mkDefault true;
+
+      # Enable colord server
+      services.colord.enable = true;
+
+      # Enable dconf
+      programs.dconf.enable = true;
+
+      # Enable org.a11y.Bus
+      services.gnome3.at-spi2-core.enable = true;
+
+      # Fix lockscreen
+      security.pam.services = {
+        cinnamon-screensaver = {};
+      };
+
+      environment.systemPackages = with pkgs.cinnamon // pkgs; [
+        desktop-file-utils
+        nixos-artwork.wallpapers.simple-dark-gray
+        onboard
+        sound-theme-freedesktop
+
+        # common-files
+        cinnamon-common
+        cinnamon-session
+        cinnamon-desktop
+        cinnamon-menus
+
+        # utils needed by some scripts
+        killall
+
+        # session requirements
+        cinnamon-screensaver
+        # cinnamon-killer-daemon: provided by cinnamon-common
+        gnome3.networkmanagerapplet # session requirement - also nm-applet not needed
+
+        # packages
+        nemo
+        cinnamon-control-center
+        cinnamon-settings-daemon
+        gnome3.libgnomekbd
+        orca
+
+        # theme
+        gnome3.adwaita-icon-theme
+        hicolor-icon-theme
+        gnome3.gnome-themes-extra
+        gtk3.out
+        mint-artwork
+        mint-themes
+        mint-x-icons
+        mint-y-icons
+        vanilla-dmz
+
+        # other
+        glib # for gsettings
+        shared-mime-info # for update-mime-database
+        xdg-user-dirs
+      ];
+
+      # Override GSettings schemas
+      environment.sessionVariables.NIX_GSETTINGS_OVERRIDES_DIR = "${nixos-gsettings-overrides}/share/gsettings-schemas/nixos-gsettings-overrides/glib-2.0/schemas";
+
+      environment.pathsToLink = [
+        # FIXME: modules should link subdirs of `/share` rather than relying on this
+        "/share" # TODO: https://github.com/NixOS/nixpkgs/issues/47173
+      ];
+
+      # Shell integration for VTE terminals
+      programs.bash.vteIntegration = mkDefault true;
+      programs.zsh.vteIntegration = mkDefault true;
+
+      # Harmonize Qt5 applications under Pantheon
+      qt5.enable = true;
+      qt5.platformTheme = "gnome";
+      qt5.style = "adwaita";
+
+      # Default Fonts
+      fonts.fonts = with pkgs; [
+        source-code-pro # Default monospace font in 3.32
+        ubuntu_font_family # required for default theme
+      ];
+    })
+
+    (mkIf serviceCfg.apps.enable {
+      programs.geary.enable = mkDefault true;
+      programs.gnome-disks.enable = mkDefault true;
+      programs.gnome-terminal.enable = mkDefault true;
+      programs.evince.enable = mkDefault true;
+      programs.file-roller.enable = mkDefault true;
+
+      environment.systemPackages = (with pkgs // pkgs.gnome3 // pkgs.cinnamon; pkgs.gnome3.removePackagesByName [
+        # cinnamon team apps
+        blueberry
+        warpinator
+
+        # external apps shipped with linux-mint
+        hexchat
+        gnome-calculator
+      ] config.environment.cinnamon.excludePackages);
+    })
+  ];
+}
diff --git a/nixos/modules/services/x11/desktop-managers/default.nix b/nixos/modules/services/x11/desktop-managers/default.nix
index 5d3a84d713994..f5559eb535419 100644
--- a/nixos/modules/services/x11/desktop-managers/default.nix
+++ b/nixos/modules/services/x11/desktop-managers/default.nix
@@ -21,6 +21,7 @@ in
     ./none.nix ./xterm.nix ./xfce.nix ./plasma5.nix ./lumina.nix
     ./lxqt.nix ./enlightenment.nix ./gnome3.nix ./kodi.nix
     ./mate.nix ./pantheon.nix ./surf-display.nix ./cde.nix
+    ./cinnamon.nix
   ];
 
   options = {
diff --git a/nixos/modules/services/x11/desktop-managers/pantheon.nix b/nixos/modules/services/x11/desktop-managers/pantheon.nix
index 6dabca6bf0969..e67e216f90d90 100644
--- a/nixos/modules/services/x11/desktop-managers/pantheon.nix
+++ b/nixos/modules/services/x11/desktop-managers/pantheon.nix
@@ -240,6 +240,8 @@ in
       # Otherwise you can't store NetworkManager Secrets with
       # "Store the password only for this user"
       programs.nm-applet.enable = true;
+      # Pantheon has its own network indicator
+      programs.nm-applet.indicator = false;
 
       # Shell integration for VTE terminals
       programs.bash.vteIntegration = mkDefault true;
diff --git a/nixos/modules/services/x11/desktop-managers/plasma5.nix b/nixos/modules/services/x11/desktop-managers/plasma5.nix
index 6d48b899d231f..149f6cbb76286 100644
--- a/nixos/modules/services/x11/desktop-managers/plasma5.nix
+++ b/nixos/modules/services/x11/desktop-managers/plasma5.nix
@@ -7,7 +7,9 @@ let
   xcfg = config.services.xserver;
   cfg = xcfg.desktopManager.plasma5;
 
-  inherit (pkgs) kdeApplications plasma5 libsForQt5 qt5;
+  inherit (pkgs) kdeApplications kdeFrameworks plasma5;
+  libsForQt5 = pkgs.libsForQt514;
+  qt5 = pkgs.qt514;
   inherit (pkgs) writeText;
 
   pulseaudio = config.hardware.pulseaudio;
@@ -83,7 +85,7 @@ let
     # recognize that software that has been removed.
     rm -fv $HOME/.cache/ksycoca*
 
-    ${pkgs.libsForQt5.kservice}/bin/kbuildsycoca5
+    ${libsForQt5.kservice}/bin/kbuildsycoca5
   '';
 
   set_XDG_CONFIG_HOME = ''
@@ -203,7 +205,9 @@ in
         KERNEL=="i2c-[0-9]*", TAG+="uaccess"
       '';
 
-      environment.systemPackages = with pkgs; with qt5; with libsForQt5; with plasma5; with kdeApplications;
+      environment.systemPackages =
+        with qt5; with libsForQt5;
+        with plasma5; with kdeApplications; with kdeFrameworks;
         [
           frameworkintegration
           kactivities
@@ -293,7 +297,7 @@ in
 
           qtvirtualkeyboard
 
-          xdg-user-dirs # Update user dirs as described in https://freedesktop.org/wiki/Software/xdg-user-dirs/
+          pkgs.xdg-user-dirs # Update user dirs as described in https://freedesktop.org/wiki/Software/xdg-user-dirs/
         ]
 
         # Phonon audio backend
@@ -301,13 +305,13 @@ in
         ++ lib.optional (cfg.phononBackend == "vlc") libsForQt5.phonon-backend-vlc
 
         # Optional hardware support features
-        ++ lib.optionals config.hardware.bluetooth.enable [ bluedevil bluez-qt openobex obexftp ]
+        ++ lib.optionals config.hardware.bluetooth.enable [ bluedevil bluez-qt pkgs.openobex pkgs.obexftp ]
         ++ lib.optional config.networking.networkmanager.enable plasma-nm
         ++ lib.optional config.hardware.pulseaudio.enable plasma-pa
         ++ lib.optional config.powerManagement.enable powerdevil
-        ++ lib.optional config.services.colord.enable colord-kde
+        ++ lib.optional config.services.colord.enable pkgs.colord-kde
         ++ lib.optionals config.services.samba.enable [ kdenetwork-filesharing pkgs.samba ]
-        ++ lib.optional config.services.xserver.wacom.enable wacomtablet;
+        ++ lib.optional config.services.xserver.wacom.enable pkgs.wacomtablet;
 
       environment.pathsToLink = [
         # FIXME: modules should link subdirs of `/share` rather than relying on this
@@ -321,7 +325,7 @@ in
 
       fonts.fonts = with pkgs; [ noto-fonts hack-font ];
       fonts.fontconfig.defaultFonts = {
-        monospace = [ "Hack" "Noto Mono" ];
+        monospace = [ "Hack" "Noto Sans Mono" ];
         sansSerif = [ "Noto Sans" ];
         serif = [ "Noto Serif" ];
       };
diff --git a/nixos/modules/services/x11/display-managers/default.nix b/nixos/modules/services/x11/display-managers/default.nix
index aa6a5ec42be85..08ce8edd66123 100644
--- a/nixos/modules/services/x11/display-managers/default.nix
+++ b/nixos/modules/services/x11/display-managers/default.nix
@@ -55,13 +55,6 @@ let
         exec &> >(tee ~/.xsession-errors)
       ''}
 
-      # Tell systemd about our $DISPLAY and $XAUTHORITY.
-      # This is needed by the ssh-agent unit.
-      #
-      # Also tell systemd about the dbus session bus address.
-      # This is required by user units using the session bus.
-      /run/current-system/systemd/bin/systemctl --user import-environment DISPLAY XAUTHORITY DBUS_SESSION_BUS_ADDRESS
-
       # Load X defaults. This should probably be safe on wayland too.
       ${xorg.xrdb}/bin/xrdb -merge ${xresourcesXft}
       if test -e ~/.Xresources; then
@@ -70,6 +63,12 @@ let
           ${xorg.xrdb}/bin/xrdb -merge ~/.Xdefaults
       fi
 
+      # Import environment variables into the systemd user environment.
+      ${optionalString (cfg.displayManager.importedVariables != []) (
+        "/run/current-system/systemd/bin/systemctl --user import-environment "
+          + toString (unique cfg.displayManager.importedVariables)
+      )}
+
       # Speed up application start by 50-150ms according to
       # http://kdemonkey.blogspot.nl/2008/04/magic-trick.html
       rm -rf "$HOME/.compose-cache"
@@ -289,6 +288,14 @@ in
         '';
       };
 
+      importedVariables = mkOption {
+        type = types.listOf (types.strMatching "[a-zA-Z_][a-zA-Z0-9_]*");
+        visible = false;
+        description = ''
+          Environment variables to import into the systemd user environment.
+        '';
+      };
+
       job = {
 
         preStart = mkOption {
@@ -332,12 +339,45 @@ in
 
       };
 
+      # Configuration for automatic login. Common for all DM.
+      autoLogin = mkOption {
+        type = types.submodule {
+          options = {
+            enable = mkOption {
+              type = types.bool;
+              default = cfg.displayManager.autoLogin.user != null;
+              description = ''
+                Automatically log in as <option>autoLogin.user</option>.
+              '';
+            };
+
+            user = mkOption {
+              type = types.nullOr types.str;
+              default = null;
+              description = ''
+                User to be used for the automatic login.
+              '';
+            };
+          };
+        };
+
+        default = {};
+        description = ''
+          Auto login configuration attrset.
+        '';
+      };
+
     };
 
   };
 
   config = {
     assertions = [
+      { assertion = cfg.displayManager.autoLogin.enable -> cfg.displayManager.autoLogin.user != null;
+        message = ''
+          services.xserver.displayManager.autoLogin.enable requires services.xserver.displayManager.autoLogin.user to be set
+        '';
+      }
       {
         assertion = cfg.desktopManager.default != null || cfg.windowManager.default != null -> cfg.displayManager.defaultSession == defaultSessionFromLegacyOptions;
         message = "You cannot use both services.xserver.displayManager.defaultSession option and legacy options (services.xserver.desktopManager.default and services.xserver.windowManager.default).";
@@ -360,6 +400,16 @@ in
 
     services.xserver.displayManager.xserverBin = "${xorg.xorgserver.out}/bin/X";
 
+    services.xserver.displayManager.importedVariables = [
+      # This is required by user units using the session bus.
+      "DBUS_SESSION_BUS_ADDRESS"
+      # These are needed by the ssh-agent unit.
+      "DISPLAY"
+      "XAUTHORITY"
+      # This is required to specify session within user units (e.g. loginctl lock-session).
+      "XDG_SESSION_ID"
+    ];
+
     systemd.user.targets.graphical-session = {
       unitConfig = {
         RefuseManualStart = false;
diff --git a/nixos/modules/services/x11/display-managers/gdm.nix b/nixos/modules/services/x11/display-managers/gdm.nix
index 622ea62f3a917..eae70a57c781d 100644
--- a/nixos/modules/services/x11/display-managers/gdm.nix
+++ b/nixos/modules/services/x11/display-managers/gdm.nix
@@ -37,6 +37,22 @@ let
 in
 
 {
+  imports = [
+    (mkRenamedOptionModule [ "services" "xserver" "displayManager" "gdm" "autoLogin" "enable" ] [
+      "services"
+      "xserver"
+      "displayManager"
+      "autoLogin"
+      "enable"
+    ])
+    (mkRenamedOptionModule [ "services" "xserver" "displayManager" "gdm" "autoLogin" "user" ] [
+      "services"
+      "xserver"
+      "displayManager"
+      "autoLogin"
+      "user"
+    ])
+  ];
 
   meta = {
     maintainers = teams.gnome.members;
@@ -48,48 +64,17 @@ in
 
     services.xserver.displayManager.gdm = {
 
-      enable = mkEnableOption ''
-        GDM, the GNOME Display Manager
-      '';
+      enable = mkEnableOption "GDM, the GNOME Display Manager";
 
-      debug = mkEnableOption ''
-        debugging messages in GDM
-      '';
+      debug = mkEnableOption "debugging messages in GDM";
 
-      autoLogin = mkOption {
-        default = {};
+      # Auto login options specific to GDM
+      autoLogin.delay = mkOption {
+        type = types.int;
+        default = 0;
         description = ''
-          Auto login configuration attrset.
+          Seconds of inactivity after which the autologin will be performed.
         '';
-
-        type = types.submodule {
-          options = {
-            enable = mkOption {
-              type = types.bool;
-              default = false;
-              description = ''
-                Automatically log in as the sepecified <option>autoLogin.user</option>.
-              '';
-            };
-
-            user = mkOption {
-              type = types.nullOr types.str;
-              default = null;
-              description = ''
-                User to be used for the autologin.
-              '';
-            };
-
-            delay = mkOption {
-              type = types.int;
-              default = 0;
-              description = ''
-                Seconds of inactivity after which the autologin will be performed.
-              '';
-            };
-
-          };
-        };
       };
 
       wayland = mkOption {
@@ -128,12 +113,6 @@ in
 
   config = mkIf cfg.gdm.enable {
 
-    assertions = [
-      { assertion = cfg.gdm.autoLogin.enable -> cfg.gdm.autoLogin.user != null;
-        message = "GDM auto-login requires services.xserver.displayManager.gdm.autoLogin.user to be set";
-      }
-    ];
-
     services.xserver.displayManager.lightdm.enable = false;
 
     users.users.gdm =
@@ -217,7 +196,6 @@ in
       KillMode = "mixed";
       IgnoreSIGPIPE = "no";
       BusName = "org.gnome.DisplayManager";
-      StandardOutput = "syslog";
       StandardError = "inherit";
       ExecReload = "${pkgs.coreutils}/bin/kill -SIGHUP $MAINPID";
       KeyringMode = "shared";
@@ -287,14 +265,14 @@ in
     environment.etc."gdm/custom.conf".text = ''
       [daemon]
       WaylandEnable=${if cfg.gdm.wayland then "true" else "false"}
-      ${optionalString cfg.gdm.autoLogin.enable (
+      ${optionalString cfg.autoLogin.enable (
         if cfg.gdm.autoLogin.delay > 0 then ''
           TimedLoginEnable=true
-          TimedLogin=${cfg.gdm.autoLogin.user}
+          TimedLogin=${cfg.autoLogin.user}
           TimedLoginDelay=${toString cfg.gdm.autoLogin.delay}
         '' else ''
           AutomaticLoginEnable=true
-          AutomaticLogin=${cfg.gdm.autoLogin.user}
+          AutomaticLogin=${cfg.autoLogin.user}
         '')
       }
 
diff --git a/nixos/modules/services/x11/display-managers/lightdm-greeters/pantheon.nix b/nixos/modules/services/x11/display-managers/lightdm-greeters/pantheon.nix
index 087c6b9c38ac0..9bc9e2bf6162c 100644
--- a/nixos/modules/services/x11/display-managers/lightdm-greeters/pantheon.nix
+++ b/nixos/modules/services/x11/display-managers/lightdm-greeters/pantheon.nix
@@ -43,7 +43,7 @@ in
     services.xserver.displayManager.lightdm.extraSeatDefaults = "greeter-show-manual-login=true";
 
     environment.etc."lightdm/io.elementary.greeter.conf".source = "${pkgs.pantheon.elementary-greeter}/etc/lightdm/io.elementary.greeter.conf";
-    environment.etc."wingpanel.d/io.elementary.greeter.whitelist".source = "${pkgs.pantheon.elementary-default-settings}/etc/wingpanel.d/io.elementary.greeter.whitelist";
+    environment.etc."wingpanel.d/io.elementary.greeter.allowed".source = "${pkgs.pantheon.elementary-default-settings}/etc/wingpanel.d/io.elementary.greeter.allowed";
 
   };
 }
diff --git a/nixos/modules/services/x11/display-managers/lightdm.nix b/nixos/modules/services/x11/display-managers/lightdm.nix
index 678cade444274..143785db0b4fc 100644
--- a/nixos/modules/services/x11/display-managers/lightdm.nix
+++ b/nixos/modules/services/x11/display-managers/lightdm.nix
@@ -53,8 +53,8 @@ let
       ${optionalString cfg.greeter.enable ''
         greeter-session = ${cfg.greeter.name}
       ''}
-      ${optionalString cfg.autoLogin.enable ''
-        autologin-user = ${cfg.autoLogin.user}
+      ${optionalString dmcfg.autoLogin.enable ''
+        autologin-user = ${dmcfg.autoLogin.user}
         autologin-user-timeout = ${toString cfg.autoLogin.timeout}
         autologin-session = ${sessionData.autologinSession}
       ''}
@@ -82,6 +82,20 @@ in
     ./lightdm-greeters/enso-os.nix
     ./lightdm-greeters/pantheon.nix
     ./lightdm-greeters/tiny.nix
+    (mkRenamedOptionModule [ "services" "xserver" "displayManager" "lightdm" "autoLogin" "enable" ] [
+      "services"
+      "xserver"
+      "displayManager"
+      "autoLogin"
+      "enable"
+    ])
+    (mkRenamedOptionModule [ "services" "xserver" "displayManager" "lightdm" "autoLogin" "user" ] [
+     "services"
+     "xserver"
+     "displayManager"
+     "autoLogin"
+     "user"
+    ])
   ];
 
   options = {
@@ -149,39 +163,13 @@ in
         description = "Extra lines to append to SeatDefaults section.";
       };
 
-      autoLogin = mkOption {
-        default = {};
+      # Configuration for automatic login specific to LightDM
+      autoLogin.timeout = mkOption {
+        type = types.int;
+        default = 0;
         description = ''
-          Configuration for automatic login.
+          Show the greeter for this many seconds before automatic login occurs.
         '';
-
-        type = types.submodule {
-          options = {
-            enable = mkOption {
-              type = types.bool;
-              default = false;
-              description = ''
-                Automatically log in as the specified <option>autoLogin.user</option>.
-              '';
-            };
-
-            user = mkOption {
-              type = types.nullOr types.str;
-              default = null;
-              description = ''
-                User to be used for the automatic login.
-              '';
-            };
-
-            timeout = mkOption {
-              type = types.int;
-              default = 0;
-              description = ''
-                Show the greeter for this many seconds before automatic login occurs.
-              '';
-            };
-          };
-        };
       };
 
     };
@@ -195,17 +183,12 @@ in
           LightDM requires services.xserver.enable to be true
         '';
       }
-      { assertion = cfg.autoLogin.enable -> cfg.autoLogin.user != null;
-        message = ''
-          LightDM auto-login requires services.xserver.displayManager.lightdm.autoLogin.user to be set
-        '';
-      }
-      { assertion = cfg.autoLogin.enable -> sessionData.autologinSession != null;
+      { assertion = dmcfg.autoLogin.enable -> sessionData.autologinSession != null;
         message = ''
           LightDM auto-login requires that services.xserver.displayManager.defaultSession is set.
         '';
       }
-      { assertion = !cfg.greeter.enable -> (cfg.autoLogin.enable && cfg.autoLogin.timeout == 0);
+      { assertion = !cfg.greeter.enable -> (dmcfg.autoLogin.enable && cfg.autoLogin.timeout == 0);
         message = ''
           LightDM can only run without greeter if automatic login is enabled and the timeout for it
           is set to zero.
@@ -218,7 +201,7 @@ in
 
     # Set default session in session chooser to a specified values – basically ignore session history.
     # Auto-login is already covered by a config value.
-    services.xserver.displayManager.job.preStart = optionalString (!cfg.autoLogin.enable && dmcfg.defaultSession != null) ''
+    services.xserver.displayManager.job.preStart = optionalString (!dmcfg.autoLogin.enable && dmcfg.defaultSession != null) ''
       ${setSessionScript}/bin/set-session ${dmcfg.defaultSession}
     '';
 
@@ -270,7 +253,6 @@ in
       KeyringMode = "shared";
       KillMode = "mixed";
       StandardError = "inherit";
-      StandardOutput = "syslog";
     };
 
     environment.etc."lightdm/lightdm.conf".source = lightdmConf;
diff --git a/nixos/modules/services/x11/display-managers/sddm.nix b/nixos/modules/services/x11/display-managers/sddm.nix
index 2f42271da872e..e63bb2e445396 100644
--- a/nixos/modules/services/x11/display-managers/sddm.nix
+++ b/nixos/modules/services/x11/display-managers/sddm.nix
@@ -61,9 +61,9 @@ let
     EnableHidpi=${if cfg.enableHidpi then "true" else "false"}
     SessionDir=${dmcfg.sessionData.desktops}/share/wayland-sessions
 
-    ${optionalString cfg.autoLogin.enable ''
+    ${optionalString dmcfg.autoLogin.enable ''
     [Autologin]
-    User=${cfg.autoLogin.user}
+    User=${dmcfg.autoLogin.user}
     Session=${autoLoginSessionName}.desktop
     Relogin=${boolToString cfg.autoLogin.relogin}
     ''}
@@ -78,6 +78,20 @@ in
   imports = [
     (mkRemovedOptionModule [ "services" "xserver" "displayManager" "sddm" "themes" ]
       "Set the option `services.xserver.displayManager.sddm.package' instead.")
+    (mkRenamedOptionModule [ "services" "xserver" "displayManager" "sddm" "autoLogin" "enable" ] [
+      "services"
+      "xserver"
+      "displayManager"
+      "autoLogin"
+      "enable"
+    ])
+    (mkRenamedOptionModule [ "services" "xserver" "displayManager" "sddm" "autoLogin" "user" ] [
+      "services"
+      "xserver"
+      "displayManager"
+      "autoLogin"
+      "user"
+    ])
   ];
 
   options = {
@@ -153,40 +167,14 @@ in
         '';
       };
 
-      autoLogin = mkOption {
-        default = {};
+      # Configuration for automatic login specific to SDDM
+      autoLogin.relogin = mkOption {
+        type = types.bool;
+        default = false;
         description = ''
-          Configuration for automatic login.
+          If true automatic login will kick in again on session exit (logout), otherwise it
+          will only log in automatically when the display-manager is started.
         '';
-
-        type = types.submodule {
-          options = {
-            enable = mkOption {
-              type = types.bool;
-              default = false;
-              description = ''
-                Automatically log in as <option>autoLogin.user</option>.
-              '';
-            };
-
-            user = mkOption {
-              type = types.nullOr types.str;
-              default = null;
-              description = ''
-                User to be used for the automatic login.
-              '';
-            };
-
-            relogin = mkOption {
-              type = types.bool;
-              default = false;
-              description = ''
-                If true automatic login will kick in again on session exit (logout), otherwise it
-                will only log in automatically when the display-manager is started.
-              '';
-            };
-          };
-        };
       };
 
     };
@@ -201,12 +189,7 @@ in
           SDDM requires services.xserver.enable to be true
         '';
       }
-      { assertion = cfg.autoLogin.enable -> cfg.autoLogin.user != null;
-        message = ''
-          SDDM auto-login requires services.xserver.displayManager.sddm.autoLogin.user to be set
-        '';
-      }
-      { assertion = cfg.autoLogin.enable -> autoLoginSessionName != null;
+      { assertion = dmcfg.autoLogin.enable -> autoLoginSessionName != null;
         message = ''
           SDDM auto-login requires that services.xserver.displayManager.defaultSession is set.
         '';
diff --git a/nixos/modules/services/x11/hardware/libinput.nix b/nixos/modules/services/x11/hardware/libinput.nix
index 48543d15499b4..9548ecb8ef6da 100644
--- a/nixos/modules/services/x11/hardware/libinput.nix
+++ b/nixos/modules/services/x11/hardware/libinput.nix
@@ -219,7 +219,6 @@ in {
         Section "InputClass"
           Identifier "libinputConfiguration"
           MatchDriver "libinput"
-          MatchTag "Touchpad"
           ${optionalString (cfg.dev != null) ''MatchDevicePath "${cfg.dev}"''}
           Option "AccelProfile" "${cfg.accelProfile}"
           ${optionalString (cfg.accelSpeed != null) ''Option "AccelSpeed" "${cfg.accelSpeed}"''}
diff --git a/nixos/modules/services/x11/imwheel.nix b/nixos/modules/services/x11/imwheel.nix
index 3923df498e794..51f72dadbd43e 100644
--- a/nixos/modules/services/x11/imwheel.nix
+++ b/nixos/modules/services/x11/imwheel.nix
@@ -61,7 +61,8 @@ in
             "--kill"
           ] ++ cfg.extraOptions);
           ExecStop = "${pkgs.procps}/bin/pkill imwheel";
-          Restart = "on-failure";
+          RestartSec = 3;
+          Restart = "always";
         };
       };
     };
diff --git a/nixos/modules/services/x11/urserver.nix b/nixos/modules/services/x11/urserver.nix
new file mode 100644
index 0000000000000..0beb62eb766a3
--- /dev/null
+++ b/nixos/modules/services/x11/urserver.nix
@@ -0,0 +1,38 @@
+# urserver service
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.services.urserver;
+in {
+
+  options.services.urserver.enable = lib.mkEnableOption "urserver";
+
+  config = lib.mkIf cfg.enable {
+
+    networking.firewall = {
+      allowedTCPPorts = [ 9510 9512 ];
+      allowedUDPPorts = [ 9511 9512 ];
+    };
+
+    systemd.user.services.urserver =  {
+      description = ''
+        Server for Unified Remote: The one-and-only remote for your computer.
+      '';
+      wantedBy = [ "graphical-session.target" ];
+      partOf = [ "graphical-session.target" ];
+      after = [ "network.target" ];
+      serviceConfig = {
+        Type = "forking";
+        ExecStart = ''
+          ${pkgs.urserver}/bin/urserver --daemon
+        '';
+        ExecStop = ''
+          ${pkgs.procps}/bin/pkill urserver
+        '';
+        RestartSec = 3;
+        Restart = "on-failure";
+      };
+    };
+  };
+
+}
diff --git a/nixos/modules/services/x11/window-managers/qtile.nix b/nixos/modules/services/x11/window-managers/qtile.nix
index ad3b65150b01d..cadc316bbc4f0 100644
--- a/nixos/modules/services/x11/window-managers/qtile.nix
+++ b/nixos/modules/services/x11/window-managers/qtile.nix
@@ -19,7 +19,7 @@ in
         waitPID=$!
       '';
     }];
-    
+
     environment.systemPackages = [ pkgs.qtile ];
   };
 }
diff --git a/nixos/modules/services/x11/window-managers/xmonad.nix b/nixos/modules/services/x11/window-managers/xmonad.nix
index 30c59b88f82f9..dba25da8260ce 100644
--- a/nixos/modules/services/x11/window-managers/xmonad.nix
+++ b/nixos/modules/services/x11/window-managers/xmonad.nix
@@ -16,6 +16,7 @@ let
                 cfg.extraPackages cfg.haskellPackages ++
                 optionals cfg.enableContribAndExtras
                 (with cfg.haskellPackages; [ xmonad-contrib xmonad-extras ]);
+    inherit (cfg) ghcArgs;
   } cfg.config;
 
 in
@@ -76,18 +77,35 @@ in
                  }
         '';
       };
+
+      xmonadCliArgs = mkOption {
+        default = [];
+        type = with lib.types; listOf str;
+        description = ''
+          Command line arguments passed to the xmonad binary.
+        '';
+      };
+
+      ghcArgs = mkOption {
+        default = [];
+        type = with lib.types; listOf str;
+        description = ''
+          Command line arguments passed to the compiler (ghc)
+          invocation when xmonad.config is set.
+        '';
+      };
+
     };
   };
   config = mkIf cfg.enable {
     services.xserver.windowManager = {
       session = [{
         name = "xmonad";
-        start = if (cfg.config != null) then ''
-          ${xmonadBin}
-          waitPID=$!
-        '' else ''
-          systemd-cat -t xmonad ${xmonad}/bin/xmonad &
-          waitPID=$!
+        start = let
+          xmonadCommand = if (cfg.config != null) then xmonadBin else "${xmonad}/bin/xmonad";
+        in ''
+           systemd-cat -t xmonad -- ${xmonadCommand} ${lib.escapeShellArgs cfg.xmonadCliArgs} &
+           waitPID=$!
         '';
       }];
     };
diff --git a/nixos/modules/services/x11/xserver.nix b/nixos/modules/services/x11/xserver.nix
index 400173745d3f9..0552095ba9557 100644
--- a/nixos/modules/services/x11/xserver.nix
+++ b/nixos/modules/services/x11/xserver.nix
@@ -113,14 +113,14 @@ let
   in concatMapStrings (getAttr "value") monitors;
 
   configFile = pkgs.runCommand "xserver.conf"
-    { xfs = optionalString (cfg.useXFS != false)
-        ''FontPath "${toString cfg.useXFS}"'';
+    { fontpath = optionalString (cfg.fontPath != null)
+        ''FontPath "${cfg.fontPath}"'';
       inherit (cfg) config;
       preferLocalBuild = true;
     }
       ''
         echo 'Section "Files"' >> $out
-        echo $xfs >> $out
+        echo $fontpath >> $out
 
         for i in ${toString fontsForXServer}; do
           if test "''${i:0:''${#NIX_STORE}}" == "$NIX_STORE"; then
@@ -151,6 +151,8 @@ in
       ./desktop-managers/default.nix
       (mkRemovedOptionModule [ "services" "xserver" "startGnuPGAgent" ]
         "See the 16.09 release notes for more information.")
+      (mkRemovedOptionModule ["services" "xserver" "useXFS" ]
+        "Use services.xserver.fontPath instead of useXFS")
     ];
 
 
@@ -481,11 +483,15 @@ in
         description = "Default colour depth.";
       };
 
-      useXFS = mkOption {
-        # FIXME: what's the type of this option?
-        default = false;
+      fontPath = mkOption {
+        type = types.nullOr types.str;
+        default = null;
         example = "unix/:7100";
-        description = "Determines how to connect to the X Font Server.";
+        description = ''
+          Set the X server FontPath. Defaults to null, which
+          means the compiled in defaults will be used. See
+          man xorg.conf for details.
+        '';
       };
 
       tty = mkOption {
diff --git a/nixos/modules/system/activation/top-level.nix b/nixos/modules/system/activation/top-level.nix
index f6739977fa4f1..fb8644dd13a60 100644
--- a/nixos/modules/system/activation/top-level.nix
+++ b/nixos/modules/system/activation/top-level.nix
@@ -92,9 +92,7 @@ let
   # `switch-to-configuration' that activates the configuration and
   # makes it bootable.
   baseSystem = pkgs.stdenvNoCC.mkDerivation {
-    name = let hn = config.networking.hostName;
-               nn = if (hn != "") then hn else "unnamed";
-        in "nixos-system-${nn}-${config.system.nixos.label}";
+    name = "nixos-system-${config.system.name}-${config.system.nixos.label}";
     preferLocalBuild = true;
     allowSubstitutes = false;
     buildCommand = systemBuilder;
@@ -265,6 +263,21 @@ in
       '';
     };
 
+    system.name = mkOption {
+      type = types.str;
+      default =
+        if config.networking.hostName == ""
+        then "unnamed"
+        else config.networking.hostName;
+      defaultText = '''networking.hostName' if non empty else "unnamed"'';
+      description = ''
+        The name of the system used in the <option>system.build.toplevel</option> derivation.
+        </para><para>
+        That derivation has the following name:
+        <literal>"nixos-system-''${config.system.name}-''${config.system.nixos.label}"</literal>
+      '';
+    };
+
   };
 
 
diff --git a/nixos/modules/system/boot/emergency-mode.nix b/nixos/modules/system/boot/emergency-mode.nix
index 9cdab84161925..ec697bcee2680 100644
--- a/nixos/modules/system/boot/emergency-mode.nix
+++ b/nixos/modules/system/boot/emergency-mode.nix
@@ -34,4 +34,4 @@ with lib;
 
   };
 
-}
\ No newline at end of file
+}
diff --git a/nixos/modules/system/boot/initrd-network.nix b/nixos/modules/system/boot/initrd-network.nix
index 0ab6e626b340e..ec794d6eb014d 100644
--- a/nixos/modules/system/boot/initrd-network.nix
+++ b/nixos/modules/system/boot/initrd-network.nix
@@ -139,7 +139,7 @@ in
     boot.initrd.postMountCommands = mkIf cfg.flushBeforeStage2 ''
       for iface in $ifaces; do
         ip address flush "$iface"
-        ip link down "$iface"
+        ip link set "$iface" down
       done
     '';
 
diff --git a/nixos/modules/system/boot/initrd-openvpn.nix b/nixos/modules/system/boot/initrd-openvpn.nix
new file mode 100644
index 0000000000000..e59bc7b6678f2
--- /dev/null
+++ b/nixos/modules/system/boot/initrd-openvpn.nix
@@ -0,0 +1,81 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.boot.initrd.network.openvpn;
+
+in
+
+{
+
+  options = {
+
+    boot.initrd.network.openvpn.enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = ''
+        Starts an OpenVPN client during initrd boot. It can be used to e.g.
+        remotely accessing the SSH service controlled by
+        <option>boot.initrd.network.ssh</option> or other network services
+        included. Service is killed when stage-1 boot is finished.
+      '';
+    };
+
+    boot.initrd.network.openvpn.configuration = mkOption {
+      type = types.path; # Same type as boot.initrd.secrets
+      description = ''
+        The configuration file for OpenVPN.
+
+        <warning>
+          <para>
+            Unless your bootloader supports initrd secrets, this configuration
+            is stored insecurely in the global Nix store.
+          </para>
+        </warning>
+      '';
+      example = "./configuration.ovpn";
+    };
+
+  };
+
+  config = mkIf (config.boot.initrd.network.enable && cfg.enable) {
+    assertions = [
+      {
+        assertion = cfg.configuration != null;
+        message = "You should specify a configuration for initrd OpenVPN";
+      }
+    ];
+
+    # Add kernel modules needed for OpenVPN
+    boot.initrd.kernelModules = [ "tun" "tap" ];
+
+    # Add openvpn and ip binaries to the initrd
+    # The shared libraries are required for DNS resolution
+    boot.initrd.extraUtilsCommands = ''
+      copy_bin_and_libs ${pkgs.openvpn}/bin/openvpn
+      copy_bin_and_libs ${pkgs.iproute}/bin/ip
+
+      cp -pv ${pkgs.glibc}/lib/libresolv.so.2 $out/lib
+      cp -pv ${pkgs.glibc}/lib/libnss_dns.so.2 $out/lib
+    '';
+
+    boot.initrd.secrets = {
+      "/etc/initrd.ovpn" = cfg.configuration;
+    };
+
+    # openvpn --version would exit with 1 instead of 0
+    boot.initrd.extraUtilsCommandsTest = ''
+      $out/bin/openvpn --show-gateway
+    '';
+
+    # Add `iproute /bin/ip` to the config, to ensure that openvpn
+    # is able to set the routes
+    boot.initrd.network.postCommands = ''
+      (cat /etc/initrd.ovpn; echo -e '\niproute /bin/ip') | \
+        openvpn /dev/stdin &
+    '';
+  };
+
+}
diff --git a/nixos/modules/system/boot/kernel_config.nix b/nixos/modules/system/boot/kernel_config.nix
index 85bd420e30446..783685c9dfe41 100644
--- a/nixos/modules/system/boot/kernel_config.nix
+++ b/nixos/modules/system/boot/kernel_config.nix
@@ -54,7 +54,7 @@ let
         type = types.bool // { merge = mergeFalseByDefault; };
         default = false;
         description = ''
-          Wether option should generate a failure when unused.
+          Whether option should generate a failure when unused.
           Upon merging values, mandatory wins over optional.
         '';
       };
diff --git a/nixos/modules/system/boot/loader/generations-dir/generations-dir-builder.sh b/nixos/modules/system/boot/loader/generations-dir/generations-dir-builder.sh
index e723b9eb7cb31..8ae23dc988c2d 100644
--- a/nixos/modules/system/boot/loader/generations-dir/generations-dir-builder.sh
+++ b/nixos/modules/system/boot/loader/generations-dir/generations-dir-builder.sh
@@ -63,7 +63,7 @@ addEntry() {
         copyToKernelsDir $kernel; kernel=$result
         copyToKernelsDir $initrd; initrd=$result
     fi
-    
+
     mkdir -p $outdir
     ln -sf $(readlink -f $path) $outdir/system
     ln -sf $(readlink -f $path/init) $outdir/init
diff --git a/nixos/modules/system/boot/loader/generic-extlinux-compatible/default.nix b/nixos/modules/system/boot/loader/generic-extlinux-compatible/default.nix
index af39c7bb68418..bd508bbe8eaa9 100644
--- a/nixos/modules/system/boot/loader/generic-extlinux-compatible/default.nix
+++ b/nixos/modules/system/boot/loader/generic-extlinux-compatible/default.nix
@@ -4,11 +4,15 @@ with lib;
 
 let
   blCfg = config.boot.loader;
+  dtCfg = config.hardware.deviceTree;
   cfg = blCfg.generic-extlinux-compatible;
 
   timeoutStr = if blCfg.timeout == null then "-1" else toString blCfg.timeout;
 
+  # The builder used to write during system activation
   builder = import ./extlinux-conf-builder.nix { inherit pkgs; };
+  # The builder exposed in populateCmd, which runs on the build architecture
+  populateBuilder = import ./extlinux-conf-builder.nix { pkgs = pkgs.buildPackages; };
 in
 {
   options = {
@@ -34,11 +38,28 @@ in
           Maximum number of configurations in the boot menu.
         '';
       };
+
+      populateCmd = mkOption {
+        type = types.str;
+        readOnly = true;
+        description = ''
+          Contains the builder command used to populate an image,
+          honoring all options except the <literal>-c &lt;path-to-default-configuration&gt;</literal>
+          argument.
+          Useful to have for sdImage.populateRootCommands
+        '';
+      };
+
     };
   };
 
-  config = mkIf cfg.enable {
-    system.build.installBootLoader = "${builder} -g ${toString cfg.configurationLimit} -t ${timeoutStr} -c";
-    system.boot.loader.id = "generic-extlinux-compatible";
-  };
+  config = let
+    builderArgs = "-g ${toString cfg.configurationLimit} -t ${timeoutStr}" + lib.optionalString (dtCfg.name != null) " -n ${dtCfg.name}";
+  in
+    mkIf cfg.enable {
+      system.build.installBootLoader = "${builder} ${builderArgs} -c";
+      system.boot.loader.id = "generic-extlinux-compatible";
+
+      boot.loader.generic-extlinux-compatible.populateCmd = "${populateBuilder} ${builderArgs}";
+    };
 }
diff --git a/nixos/modules/system/boot/loader/generic-extlinux-compatible/extlinux-conf-builder.sh b/nixos/modules/system/boot/loader/generic-extlinux-compatible/extlinux-conf-builder.sh
index 0092ee92b62fd..854684b87face 100644
--- a/nixos/modules/system/boot/loader/generic-extlinux-compatible/extlinux-conf-builder.sh
+++ b/nixos/modules/system/boot/loader/generic-extlinux-compatible/extlinux-conf-builder.sh
@@ -6,7 +6,7 @@ export PATH=/empty
 for i in @path@; do PATH=$PATH:$i/bin; done
 
 usage() {
-    echo "usage: $0 -t <timeout> -c <path-to-default-configuration> [-d <boot-dir>] [-g <num-generations>]" >&2
+    echo "usage: $0 -t <timeout> -c <path-to-default-configuration> [-d <boot-dir>] [-g <num-generations>] [-n <dtbName>]" >&2
     exit 1
 }
 
@@ -15,7 +15,7 @@ default=                # Default configuration
 target=/boot            # Target directory
 numGenerations=0        # Number of other generations to include in the menu
 
-while getopts "t:c:d:g:" opt; do
+while getopts "t:c:d:g:n:" opt; do
     case "$opt" in
         t) # U-Boot interprets '0' as infinite and negative as instant boot
             if [ "$OPTARG" -lt 0 ]; then
@@ -29,6 +29,7 @@ while getopts "t:c:d:g:" opt; do
         c) default="$OPTARG" ;;
         d) target="$OPTARG" ;;
         g) numGenerations="$OPTARG" ;;
+        n) dtbName="$OPTARG" ;;
         \?) usage ;;
     esac
 done
@@ -96,7 +97,17 @@ addEntry() {
     echo "  LINUX ../nixos/$(basename $kernel)"
     echo "  INITRD ../nixos/$(basename $initrd)"
     if [ -d "$dtbDir" ]; then
-        echo "  FDTDIR ../nixos/$(basename $dtbs)"
+        # if a dtbName was specified explicitly, use that, else use FDTDIR
+        if [ -n "$dtbName" ]; then
+            echo "  FDT ../nixos/$(basename $dtbs)/${dtbName}"
+        else
+            echo "  FDTDIR ../nixos/$(basename $dtbs)"
+        fi
+    else
+        if [ -n "$dtbName" ]; then
+            echo "Explicitly requested dtbName $dtbName, but there's no FDTDIR - bailing out." >&2
+            exit 1
+        fi
     fi
     echo "  APPEND systemConfig=$path init=$path/init $extraParams"
 }
diff --git a/nixos/modules/system/boot/loader/grub/grub.nix b/nixos/modules/system/boot/loader/grub/grub.nix
index 3975372e15ec5..20e39628eabbc 100644
--- a/nixos/modules/system/boot/loader/grub/grub.nix
+++ b/nixos/modules/system/boot/loader/grub/grub.nix
@@ -55,11 +55,14 @@ let
       storePath = config.boot.loader.grub.storePath;
       bootloaderId = if args.efiBootloaderId == null then "NixOS${efiSysMountPoint'}" else args.efiBootloaderId;
       timeout = if config.boot.loader.timeout == null then -1 else config.boot.loader.timeout;
+      users = if cfg.users == {} || cfg.version != 1 then cfg.users else throw "GRUB version 1 does not support user accounts.";
+      theme = f cfg.theme;
       inherit efiSysMountPoint;
       inherit (args) devices;
       inherit (efi) canTouchEfiVariables;
       inherit (cfg)
         version extraConfig extraPerEntryConfig extraEntries forceInstall useOSProber
+        extraGrubInstallArgs
         extraEntriesBeforeNixOS extraPrepareConfig configurationLimit copyKernels
         default fsIdentifier efiSupport efiInstallAsRemovable gfxmodeEfi gfxmodeBios gfxpayloadEfi gfxpayloadBios;
       path = with pkgs; makeBinPath (
@@ -137,6 +140,67 @@ in
         '';
       };
 
+      users = mkOption {
+        default = {};
+        example = {
+          root = { hashedPasswordFile = "/path/to/file"; };
+        };
+        description = ''
+          User accounts for GRUB. When specified, the GRUB command line and
+          all boot options except the default are password-protected.
+          All passwords and hashes provided will be stored in /boot/grub/grub.cfg,
+          and will be visible to any local user who can read this file. Additionally,
+          any passwords and hashes provided directly in a Nix configuration
+          (as opposed to external files) will be copied into the Nix store, and
+          will be visible to all local users.
+        '';
+        type = with types; attrsOf (submodule {
+          options = {
+            hashedPasswordFile = mkOption {
+              example = "/path/to/file";
+              default = null;
+              type = with types; uniq (nullOr str);
+              description = ''
+                Specifies the path to a file containing the password hash
+                for the account, generated with grub-mkpasswd-pbkdf2.
+                This hash will be stored in /boot/grub/grub.cfg, and will
+                be visible to any local user who can read this file.
+              '';
+            };
+            hashedPassword = mkOption {
+              example = "grub.pbkdf2.sha512.10000.674DFFDEF76E13EA...2CC972B102CF4355";
+              default = null;
+              type = with types; uniq (nullOr str);
+              description = ''
+                Specifies the password hash for the account,
+                generated with grub-mkpasswd-pbkdf2.
+                This hash will be copied to the Nix store, and will be visible to all local users.
+              '';
+            };
+            passwordFile = mkOption {
+              example = "/path/to/file";
+              default = null;
+              type = with types; uniq (nullOr str);
+              description = ''
+                Specifies the path to a file containing the
+                clear text password for the account.
+                This password will be stored in /boot/grub/grub.cfg, and will
+                be visible to any local user who can read this file.
+              '';
+            };
+            password = mkOption {
+              example = "Pa$$w0rd!";
+              default = null;
+              type = with types; uniq (nullOr str);
+              description = ''
+                Specifies the clear text password for the account.
+                This password will be copied to the Nix store, and will be visible to all local users.
+              '';
+            };
+          };
+        });
+      };
+
       mirroredBoots = mkOption {
         default = [ ];
         example = [
@@ -236,6 +300,33 @@ in
         '';
       };
 
+      extraGrubInstallArgs = mkOption {
+        default = [ ];
+        example = [ "--modules=nativedisk ahci pata part_gpt part_msdos diskfilter mdraid1x lvm ext2" ];
+        type = types.listOf types.str;
+        description = ''
+          Additional arguments passed to <literal>grub-install</literal>.
+
+          A use case for this is to build specific GRUB2 modules
+          directly into the GRUB2 kernel image, so that they are available
+          and activated even in the <literal>grub rescue</literal> shell.
+
+          They are also necessary when the BIOS/UEFI is bugged and cannot
+          correctly read large disks (e.g. above 2 TB), so GRUB2's own
+          <literal>nativedisk</literal> and related modules can be used
+          to use its own disk drivers. The example shows one such case.
+          This is also useful for booting from USB.
+          See the
+          <link xlink:href="http://git.savannah.gnu.org/cgit/grub.git/tree/grub-core/commands/nativedisk.c?h=grub-2.04#n326">
+          GRUB source code
+          </link>
+          for which disk modules are available.
+
+          The list elements are passed directly as <literal>argv</literal>
+          arguments to the <literal>grub-install</literal> program, in order.
+        '';
+      };
+
       extraPerEntryConfig = mkOption {
         default = "";
         example = "root (hd0)";
@@ -336,6 +427,19 @@ in
         '';
       };
 
+      theme = mkOption {
+        type = types.nullOr types.path;
+        example = literalExample "pkgs.nixos-grub2-theme";
+        default = null;
+        description = ''
+          Grub theme to be used.
+
+          <note><para>
+          This options has no effect for GRUB 1.
+          </para></note>
+        '';
+      };
+
       splashMode = mkOption {
         type = types.enum [ "normal" "stretch" ];
         default = "stretch";
@@ -607,7 +711,7 @@ in
         in pkgs.writeScript "install-grub.sh" (''
         #!${pkgs.runtimeShell}
         set -e
-        export PERL5LIB=${with pkgs.perlPackages; makePerlPath [ FileSlurp XMLLibXML XMLSAX XMLSAXBase ListCompare ]}
+        export PERL5LIB=${with pkgs.perlPackages; makePerlPath [ FileSlurp FileCopyRecursive XMLLibXML XMLSAX XMLSAXBase ListCompare JSON ]}
         ${optionalString cfg.enableCryptodisk "export GRUB_ENABLE_CRYPTODISK=y"}
       '' + flip concatMapStrings cfg.mirroredBoots (args: ''
         ${pkgs.perl}/bin/perl ${install-grub-pl} ${grubConfig args} $@
diff --git a/nixos/modules/system/boot/loader/grub/install-grub.pl b/nixos/modules/system/boot/loader/grub/install-grub.pl
index e469b18abd098..59f5638044fe9 100644
--- a/nixos/modules/system/boot/loader/grub/install-grub.pl
+++ b/nixos/modules/system/boot/loader/grub/install-grub.pl
@@ -6,8 +6,11 @@ use File::Basename;
 use File::Path;
 use File::stat;
 use File::Copy;
+use File::Copy::Recursive qw(rcopy pathrm);
 use File::Slurp;
 use File::Temp;
+use JSON;
+use File::Find;
 require List::Compare;
 use POSIX;
 use Cwd;
@@ -20,6 +23,16 @@ my $dom = XML::LibXML->load_xml(location => $ARGV[0]);
 
 sub get { my ($name) = @_; return $dom->findvalue("/expr/attrs/attr[\@name = '$name']/*/\@value"); }
 
+sub getList {
+    my ($name) = @_;
+    my @list = ();
+    foreach my $entry ($dom->findnodes("/expr/attrs/attr[\@name = '$name']/list/string/\@value")) {
+        $entry = $entry->findvalue(".") or die;
+        push(@list, $entry);
+    }
+    return @list;
+}
+
 sub readFile {
     my ($fn) = @_; local $/ = undef;
     open FILE, "<$fn" or return undef; my $s = <FILE>; close FILE;
@@ -71,6 +84,7 @@ my $gfxpayloadBios = get("gfxpayloadBios");
 my $bootloaderId = get("bootloaderId");
 my $forceInstall = get("forceInstall");
 my $font = get("font");
+my $theme = get("theme");
 $ENV{'PATH'} = get("path");
 
 die "unsupported GRUB version\n" if $grubVersion != 1 && $grubVersion != 2;
@@ -241,12 +255,51 @@ if ($grubVersion == 1) {
         timeout $timeout
     ";
     if ($splashImage) {
-        copy $splashImage, "$bootPath/background.xpm.gz" or die "cannot copy $splashImage to $bootPath\n";
+        copy $splashImage, "$bootPath/background.xpm.gz" or die "cannot copy $splashImage to $bootPath: $!\n";
         $conf .= "splashimage " . ($grubBoot->path eq "/" ? "" : $grubBoot->path) . "/background.xpm.gz\n";
     }
 }
 
 else {
+    my @users = ();
+    foreach my $user ($dom->findnodes('/expr/attrs/attr[@name = "users"]/attrs/attr')) {
+        my $name = $user->findvalue('@name') or die;
+        my $hashedPassword = $user->findvalue('./attrs/attr[@name = "hashedPassword"]/string/@value');
+        my $hashedPasswordFile = $user->findvalue('./attrs/attr[@name = "hashedPasswordFile"]/string/@value');
+        my $password = $user->findvalue('./attrs/attr[@name = "password"]/string/@value');
+        my $passwordFile = $user->findvalue('./attrs/attr[@name = "passwordFile"]/string/@value');
+
+        if ($hashedPasswordFile) {
+            open(my $f, '<', $hashedPasswordFile) or die "Can't read file '$hashedPasswordFile'!";
+            $hashedPassword = <$f>;
+            chomp $hashedPassword;
+        }
+        if ($passwordFile) {
+            open(my $f, '<', $passwordFile) or die "Can't read file '$passwordFile'!";
+            $password = <$f>;
+            chomp $password;
+        }
+
+        if ($hashedPassword) {
+            if (index($hashedPassword, "grub.pbkdf2.") == 0) {
+                $conf .= "\npassword_pbkdf2 $name $hashedPassword";
+            }
+            else {
+                die "Password hash for GRUB user '$name' is not valid!";
+            }
+        }
+        elsif ($password) {
+            $conf .= "\npassword $name $password";
+        }
+        else {
+            die "GRUB user '$name' has no password!";
+        }
+        push(@users, $name);
+    }
+    if (@users) {
+        $conf .= "\nset superusers=\"" . join(' ',@users) . "\"\n";
+    }
+
     if ($copyKernels == 0) {
         $conf .= "
             " . $grubStore->search;
@@ -280,7 +333,7 @@ else {
     ";
 
     if ($font) {
-        copy $font, "$bootPath/converted-font.pf2" or die "cannot copy $font to $bootPath\n";
+        copy $font, "$bootPath/converted-font.pf2" or die "cannot copy $font to $bootPath: $!\n";
         $conf .= "
             insmod font
             if loadfont " . ($grubBoot->path eq "/" ? "" : $grubBoot->path) . "/converted-font.pf2; then
@@ -308,7 +361,7 @@ else {
 		    background_color '$backgroundColor'
 		    ";
 		}
-        copy $splashImage, "$bootPath/background$suffix" or die "cannot copy $splashImage to $bootPath\n";
+        copy $splashImage, "$bootPath/background$suffix" or die "cannot copy $splashImage to $bootPath: $!\n";
         $conf .= "
             insmod " . substr($suffix, 1) . "
             if background_image --mode '$splashMode' " . ($grubBoot->path eq "/" ? "" : $grubBoot->path) . "/background$suffix; then
@@ -320,6 +373,28 @@ else {
             fi
         ";
     }
+
+    rmtree("$bootPath/theme") or die "cannot clean up theme folder in $bootPath\n" if -e "$bootPath/theme";
+
+    if ($theme) {
+        # Copy theme
+        rcopy($theme, "$bootPath/theme") or die "cannot copy $theme to $bootPath\n";
+        $conf .= "
+            # Sets theme.
+            set theme=" . ($grubBoot->path eq "/" ? "" : $grubBoot->path) . "/theme/theme.txt
+            export theme
+            # Load theme fonts, if any
+         ";
+
+         find( { wanted => sub {
+             if ($_ =~ /\.pf2$/i) {
+                 $font = File::Spec->abs2rel($File::Find::name, $theme);
+                 $conf .= "
+                     loadfont " . ($grubBoot->path eq "/" ? "" : $grubBoot->path) . "/theme/$font
+                 ";
+             }
+         }, no_chdir => 1 }, $theme );
+     }
 }
 
 $conf .= "$extraConfig\n";
@@ -342,15 +417,15 @@ sub copyToKernelsDir {
     # kernels or initrd if this script is ever interrupted.
     if (! -e $dst) {
         my $tmp = "$dst.tmp";
-        copy $path, $tmp or die "cannot copy $path to $tmp\n";
-        rename $tmp, $dst or die "cannot rename $tmp to $dst\n";
+        copy $path, $tmp or die "cannot copy $path to $tmp: $!\n";
+        rename $tmp, $dst or die "cannot rename $tmp to $dst: $!\n";
     }
     $copied{$dst} = 1;
     return ($grubBoot->path eq "/" ? "" : $grubBoot->path) . "/kernels/$name";
 }
 
 sub addEntry {
-    my ($name, $path) = @_;
+    my ($name, $path, $options) = @_;
     return unless -e "$path/kernel" && -e "$path/initrd";
 
     my $kernel = copyToKernelsDir(Cwd::abs_path("$path/kernel"));
@@ -366,10 +441,10 @@ sub addEntry {
       # Make sure initrd is not world readable (won't work if /boot is FAT)
       umask 0137;
       my $initrdSecretsPathTemp = File::Temp::mktemp("$initrdSecretsPath.XXXXXXXX");
-      system("$path/append-initrd-secrets", $initrdSecretsPathTemp) == 0 or die "failed to create initrd secrets\n";
+      system("$path/append-initrd-secrets", $initrdSecretsPathTemp) == 0 or die "failed to create initrd secrets: $!\n";
       # Check whether any secrets were actually added
       if (-e $initrdSecretsPathTemp && ! -z _) {
-        rename $initrdSecretsPathTemp, $initrdSecretsPath or die "failed to move initrd secrets into place\n";
+        rename $initrdSecretsPathTemp, $initrdSecretsPath or die "failed to move initrd secrets into place: $!\n";
         $copied{$initrdSecretsPath} = 1;
         $initrd .= " " . ($grubBoot->path eq "/" ? "" : $grubBoot->path) . "/kernels/$initrdName-secrets";
       } else {
@@ -396,7 +471,7 @@ sub addEntry {
         $conf .= "  " . ($xen ? "module" : "kernel") . " $kernel $kernelParams\n";
         $conf .= "  " . ($xen ? "module" : "initrd") . " $initrd\n\n";
     } else {
-        $conf .= "menuentry \"$name\" {\n";
+        $conf .= "menuentry \"$name\" " . ($options||"") . " {\n";
         $conf .= $grubBoot->search . "\n";
         if ($copyKernels == 0) {
             $conf .= $grubStore->search . "\n";
@@ -413,7 +488,7 @@ sub addEntry {
 # Add default entries.
 $conf .= "$extraEntries\n" if $extraEntriesBeforeNixOS;
 
-addEntry("NixOS - Default", $defaultConfig);
+addEntry("NixOS - Default", $defaultConfig, "--unrestricted");
 
 $conf .= "$extraEntries\n" unless $extraEntriesBeforeNixOS;
 
@@ -536,7 +611,7 @@ if (get("useOSProber") eq "true") {
 }
 
 # Atomically switch to the new config
-rename $tmpFile, $confFile or die "cannot rename $tmpFile to $confFile\n";
+rename $tmpFile, $confFile or die "cannot rename $tmpFile to $confFile: $!\n";
 
 
 # Remove obsolete files from $bootPath/kernels.
@@ -557,9 +632,12 @@ struct(GrubState => {
     efi => '$',
     devices => '$',
     efiMountPoint => '$',
+    extraGrubInstallArgs => '@',
 });
+# If you add something to the state file, only add it to the end
+# because it is read line-by-line.
 sub readGrubState {
-    my $defaultGrubState = GrubState->new(name => "", version => "", efi => "", devices => "", efiMountPoint => "" );
+    my $defaultGrubState = GrubState->new(name => "", version => "", efi => "", devices => "", efiMountPoint => "", extraGrubInstallArgs => () );
     open FILE, "<$bootPath/grub/state" or return $defaultGrubState;
     local $/ = "\n";
     my $name = <FILE>;
@@ -572,24 +650,37 @@ sub readGrubState {
     chomp($devices);
     my $efiMountPoint = <FILE>;
     chomp($efiMountPoint);
+    # Historically, arguments in the state file were one per each line, but that
+    # gets really messy when newlines are involved, structured arguments
+    # like lists are needed (they have to have a separator encoding), or even worse,
+    # when we need to remove a setting in the future. Thus, the 6th line is a JSON
+    # object that can store structured data, with named keys, and all new state
+    # should go in there.
+    my $jsonStateLine = <FILE>;
+    # For historical reasons we do not check the values above for un-definedness
+    # (that is, when the state file has too few lines and EOF is reached),
+    # because the above come from the first version of this logic and are thus
+    # guaranteed to be present.
+    $jsonStateLine = defined $jsonStateLine ? $jsonStateLine : '{}'; # empty JSON object
+    chomp($jsonStateLine);
+    if ($jsonStateLine eq "") {
+        $jsonStateLine = '{}'; # empty JSON object
+    }
+    my %jsonState = %{decode_json($jsonStateLine)};
+    my @extraGrubInstallArgs = exists($jsonState{'extraGrubInstallArgs'}) ? @{$jsonState{'extraGrubInstallArgs'}} : ();
     close FILE;
-    my $grubState = GrubState->new(name => $name, version => $version, efi => $efi, devices => $devices, efiMountPoint => $efiMountPoint );
+    my $grubState = GrubState->new(name => $name, version => $version, efi => $efi, devices => $devices, efiMountPoint => $efiMountPoint, extraGrubInstallArgs => \@extraGrubInstallArgs );
     return $grubState
 }
 
-sub getDeviceTargets {
-    my @devices = ();
-    foreach my $dev ($dom->findnodes('/expr/attrs/attr[@name = "devices"]/list/string/@value')) {
-        $dev = $dev->findvalue(".") or die;
-        push(@devices, $dev);
-    }
-    return @devices;
-}
-my @deviceTargets = getDeviceTargets();
+my @deviceTargets = getList('devices');
 my $prevGrubState = readGrubState();
 my @prevDeviceTargets = split/,/, $prevGrubState->devices;
+my @extraGrubInstallArgs = getList('extraGrubInstallArgs');
+my @prevExtraGrubInstallArgs = @{$prevGrubState->extraGrubInstallArgs};
 
 my $devicesDiffer = scalar (List::Compare->new( '-u', '-a', \@deviceTargets, \@prevDeviceTargets)->get_symmetric_difference());
+my $extraGrubInstallArgsDiffer = scalar (List::Compare->new( '-u', '-a', \@extraGrubInstallArgs, \@prevExtraGrubInstallArgs)->get_symmetric_difference());
 my $nameDiffer = get("fullName") ne $prevGrubState->name;
 my $versionDiffer = get("fullVersion") ne $prevGrubState->version;
 my $efiDiffer = $efiTarget ne $prevGrubState->efi;
@@ -598,25 +689,25 @@ if (($ENV{'NIXOS_INSTALL_GRUB'} // "") eq "1") {
     warn "NIXOS_INSTALL_GRUB env var deprecated, use NIXOS_INSTALL_BOOTLOADER";
     $ENV{'NIXOS_INSTALL_BOOTLOADER'} = "1";
 }
-my $requireNewInstall = $devicesDiffer || $nameDiffer || $versionDiffer || $efiDiffer || $efiMountPointDiffer || (($ENV{'NIXOS_INSTALL_BOOTLOADER'} // "") eq "1");
+my $requireNewInstall = $devicesDiffer || $extraGrubInstallArgsDiffer || $nameDiffer || $versionDiffer || $efiDiffer || $efiMountPointDiffer || (($ENV{'NIXOS_INSTALL_BOOTLOADER'} // "") eq "1");
 
 # install a symlink so that grub can detect the boot drive
-my $tmpDir = File::Temp::tempdir(CLEANUP => 1) or die "Failed to create temporary space";
-symlink "$bootPath", "$tmpDir/boot" or die "Failed to symlink $tmpDir/boot";
+my $tmpDir = File::Temp::tempdir(CLEANUP => 1) or die "Failed to create temporary space: $!";
+symlink "$bootPath", "$tmpDir/boot" or die "Failed to symlink $tmpDir/boot: $!";
 
 # install non-EFI GRUB
 if (($requireNewInstall != 0) && ($efiTarget eq "no" || $efiTarget eq "both")) {
     foreach my $dev (@deviceTargets) {
         next if $dev eq "nodev";
         print STDERR "installing the GRUB $grubVersion boot loader on $dev...\n";
-        my @command = ("$grub/sbin/grub-install", "--recheck", "--root-directory=$tmpDir", Cwd::abs_path($dev));
+        my @command = ("$grub/sbin/grub-install", "--recheck", "--root-directory=$tmpDir", Cwd::abs_path($dev), @extraGrubInstallArgs);
         if ($forceInstall eq "true") {
             push @command, "--force";
         }
         if ($grubTarget ne "") {
             push @command, "--target=$grubTarget";
         }
-        (system @command) == 0 or die "$0: installation of GRUB on $dev failed\n";
+        (system @command) == 0 or die "$0: installation of GRUB on $dev failed: $!\n";
     }
 }
 
@@ -624,7 +715,7 @@ if (($requireNewInstall != 0) && ($efiTarget eq "no" || $efiTarget eq "both")) {
 # install EFI GRUB
 if (($requireNewInstall != 0) && ($efiTarget eq "only" || $efiTarget eq "both")) {
     print STDERR "installing the GRUB $grubVersion EFI boot loader into $efiSysMountPoint...\n";
-    my @command = ("$grubEfi/sbin/grub-install", "--recheck", "--target=$grubTargetEfi", "--boot-directory=$bootPath", "--efi-directory=$efiSysMountPoint");
+    my @command = ("$grubEfi/sbin/grub-install", "--recheck", "--target=$grubTargetEfi", "--boot-directory=$bootPath", "--efi-directory=$efiSysMountPoint", @extraGrubInstallArgs);
     if ($forceInstall eq "true") {
         push @command, "--force";
     }
@@ -635,17 +726,29 @@ if (($requireNewInstall != 0) && ($efiTarget eq "only" || $efiTarget eq "both"))
         push @command, "--removable" if $efiInstallAsRemovable eq "true";
     }
 
-    (system @command) == 0 or die "$0: installation of GRUB EFI into $efiSysMountPoint failed\n";
+    (system @command) == 0 or die "$0: installation of GRUB EFI into $efiSysMountPoint failed: $!\n";
 }
 
 
 # update GRUB state file
 if ($requireNewInstall != 0) {
-    open FILE, ">$bootPath/grub/state" or die "cannot create $bootPath/grub/state: $!\n";
+    # Temp file for atomic rename.
+    my $stateFile = "$bootPath/grub/state";
+    my $stateFileTmp = $stateFile . ".tmp";
+
+    open FILE, ">$stateFileTmp" or die "cannot create $stateFileTmp: $!\n";
     print FILE get("fullName"), "\n" or die;
     print FILE get("fullVersion"), "\n" or die;
     print FILE $efiTarget, "\n" or die;
     print FILE join( ",", @deviceTargets ), "\n" or die;
     print FILE $efiSysMountPoint, "\n" or die;
+    my %jsonState = (
+        extraGrubInstallArgs => \@extraGrubInstallArgs
+    );
+    my $jsonStateLine = encode_json(\%jsonState);
+    print FILE $jsonStateLine, "\n" or die;
     close FILE or die;
+
+    # Atomically switch to the new state file
+    rename $stateFileTmp, $stateFile or die "cannot rename $stateFileTmp to $stateFile: $!\n";
 }
diff --git a/nixos/modules/system/boot/loader/init-script/init-script-builder.sh b/nixos/modules/system/boot/loader/init-script/init-script-builder.sh
index 6f48d2539acee..2a1ec479fea04 100644
--- a/nixos/modules/system/boot/loader/init-script/init-script-builder.sh
+++ b/nixos/modules/system/boot/loader/init-script/init-script-builder.sh
@@ -53,7 +53,7 @@ addEntry() {
       echo "exec $stage2"
     )"
 
-    [ "$path" != "$defaultConfig" ] || { 
+    [ "$path" != "$defaultConfig" ] || {
       echo "$content" > $tmp
       echo "# older configurations: $targetOther" >> $tmp
       chmod +x $tmp
diff --git a/nixos/modules/system/boot/loader/raspberrypi/raspberrypi-builder.nix b/nixos/modules/system/boot/loader/raspberrypi/raspberrypi-builder.nix
index e75aa9d138756..7eb52e3d021ff 100644
--- a/nixos/modules/system/boot/loader/raspberrypi/raspberrypi-builder.nix
+++ b/nixos/modules/system/boot/loader/raspberrypi/raspberrypi-builder.nix
@@ -3,8 +3,8 @@
 pkgs.substituteAll {
   src = ./raspberrypi-builder.sh;
   isExecutable = true;
-  inherit (pkgs.buildPackages) bash;
-  path = with pkgs.buildPackages; [coreutils gnused gnugrep];
+  inherit (pkgs) bash;
+  path = [pkgs.coreutils pkgs.gnused pkgs.gnugrep];
   firmware = pkgs.raspberrypifw;
   inherit configTxt;
 }
diff --git a/nixos/modules/system/boot/loader/raspberrypi/raspberrypi-builder.sh b/nixos/modules/system/boot/loader/raspberrypi/raspberrypi-builder.sh
index c8b5bf2e61af8..0541ca1ba6221 100644
--- a/nixos/modules/system/boot/loader/raspberrypi/raspberrypi-builder.sh
+++ b/nixos/modules/system/boot/loader/raspberrypi/raspberrypi-builder.sh
@@ -1,4 +1,7 @@
-#! @bash@/bin/sh -e
+#! @bash@/bin/sh
+
+# This can end up being called disregarding the shebang.
+set -e
 
 shopt -s nullglob
 
diff --git a/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py b/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
index 97e824fe629ce..65c7b825f8559 100644
--- a/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
+++ b/nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py
@@ -200,7 +200,9 @@ def main():
     else:
         # Update bootloader to latest if needed
         systemd_version = subprocess.check_output(["@systemd@/bin/bootctl", "--version"], universal_newlines=True).split()[1]
-        sdboot_status = subprocess.check_output(["@systemd@/bin/bootctl", "--path=@efiSysMountPoint@", "status"], universal_newlines=True)
+        # Ideally this should use check_output as well, but as a temporary
+        # work-around for #97433 we ignore any errors.
+        sdboot_status = subprocess.run(["@systemd@/bin/bootctl", "--path=@efiSysMountPoint@", "status"], universal_newlines=True, stdout=subprocess.PIPE).stdout
 
         # See status_binaries() in systemd bootctl.c for code which generates this
         m = re.search("^\W+File:.*/EFI/(BOOT|systemd)/.*\.efi \(systemd-boot (\d+)\)$",
diff --git a/nixos/modules/system/boot/loader/systemd-boot/systemd-boot.nix b/nixos/modules/system/boot/loader/systemd-boot/systemd-boot.nix
index 22d459ceb04f1..f0bd76a3c1d23 100644
--- a/nixos/modules/system/boot/loader/systemd-boot/systemd-boot.nix
+++ b/nixos/modules/system/boot/loader/systemd-boot/systemd-boot.nix
@@ -64,10 +64,10 @@ in {
       example = 120;
       type = types.nullOr types.int;
       description = ''
-        Maximum number of latest generations in the boot menu. 
+        Maximum number of latest generations in the boot menu.
         Useful to prevent boot partition running out of disk space.
 
-        <literal>null</literal> means no limit i.e. all generations 
+        <literal>null</literal> means no limit i.e. all generations
         that were not garbage collected yet.
       '';
     };
diff --git a/nixos/modules/system/boot/luksroot.nix b/nixos/modules/system/boot/luksroot.nix
index 31f1e22cda32c..88190e8200b16 100644
--- a/nixos/modules/system/boot/luksroot.nix
+++ b/nixos/modules/system/boot/luksroot.nix
@@ -140,7 +140,7 @@ let
     umount /crypt-ramfs 2>/dev/null
   '';
 
-  openCommand = name': { name, device, header, keyFile, keyFileSize, keyFileOffset, allowDiscards, yubikey, gpgCard, fido2, fallbackToPassword, ... }: assert name' == name;
+  openCommand = name': { name, device, header, keyFile, keyFileSize, keyFileOffset, allowDiscards, yubikey, gpgCard, fido2, fallbackToPassword, preOpenCommands, postOpenCommands,... }: assert name' == name;
   let
     csopen   = "cryptsetup luksOpen ${device} ${name} ${optionalString allowDiscards "--allow-discards"} ${optionalString (header != null) "--header=${header}"}";
     cschange = "cryptsetup luksChangeKey ${device} ${optionalString (header != null) "--header=${header}"}";
@@ -412,11 +412,17 @@ let
     }
     ''}
 
+    # commands to run right before we mount our device
+    ${preOpenCommands}
+
     ${if (luks.yubikeySupport && (yubikey != null)) || (luks.gpgSupport && (gpgCard != null)) || (luks.fido2Support && (fido2.credential != null)) then ''
     open_with_hardware
     '' else ''
     open_normally
     ''}
+
+    # commands to run right after we mounted our device
+    ${postOpenCommands}
   '';
 
   askPass = pkgs.writeScriptBin "cryptsetup-askpass" ''
@@ -467,8 +473,6 @@ in
         [ "aes" "aes_generic" "blowfish" "twofish"
           "serpent" "cbc" "xts" "lrw" "sha1" "sha256" "sha512"
           "af_alg" "algif_skcipher"
-
-          (if pkgs.stdenv.hostPlatform.system == "x86_64-linux" then "aes_x86_64" else "aes_i586")
         ];
       description = ''
         A list of cryptographic kernel modules needed to decrypt the root device(s).
@@ -512,7 +516,7 @@ in
         <filename>/dev/mapper/<replaceable>name</replaceable></filename>.
       '';
 
-      type = with types; loaOf (submodule (
+      type = with types; attrsOf (submodule (
         { name, ... }: { options = {
 
           name = mkOption {
@@ -637,7 +641,7 @@ in
             credential = mkOption {
               default = null;
               example = "f1d00200d8dc783f7fb1e10ace8da27f8312d72692abfca2f7e4960a73f48e82e1f7571f6ebfcee9fb434f9886ccc8fcc52a6614d8d2";
-              type = types.str;
+              type = types.nullOr types.str;
               description = "The FIDO2 credential ID.";
             };
 
@@ -735,6 +739,30 @@ in
               };
             });
           };
+
+          preOpenCommands = mkOption {
+            type = types.lines;
+            default = "";
+            example = ''
+              mkdir -p /tmp/persistent
+              mount -t zfs rpool/safe/persistent /tmp/persistent
+            '';
+            description = ''
+              Commands that should be run right before we try to mount our LUKS device.
+              This can be useful, if the keys needed to open the drive is on another partion.
+            '';
+          };
+
+          postOpenCommands = mkOption {
+            type = types.lines;
+            default = "";
+            example = ''
+              umount /tmp/persistent
+            '';
+            description = ''
+              Commands that should be run right after we have mounted our LUKS device.
+            '';
+          };
         };
       }));
     };
diff --git a/nixos/modules/system/boot/modprobe.nix b/nixos/modules/system/boot/modprobe.nix
index dee0ab470c992..c75f32c4d99ab 100644
--- a/nixos/modules/system/boot/modprobe.nix
+++ b/nixos/modules/system/boot/modprobe.nix
@@ -28,7 +28,7 @@ with lib;
         Any additional configuration to be appended to the generated
         <filename>modprobe.conf</filename>.  This is typically used to
         specify module options.  See
-        <citerefentry><refentrytitle>modprobe.conf</refentrytitle>
+        <citerefentry><refentrytitle>modprobe.d</refentrytitle>
         <manvolnum>5</manvolnum></citerefentry> for details.
       '';
       type = types.lines;
diff --git a/nixos/modules/system/boot/networkd.nix b/nixos/modules/system/boot/networkd.nix
index b0545363b3300..47689b2a4700a 100644
--- a/nixos/modules/system/boot/networkd.nix
+++ b/nixos/modules/system/boot/networkd.nix
@@ -8,359 +8,714 @@ let
 
   cfg = config.systemd.network;
 
-  checkLink = checkUnitConfig "Link" [
-    (assertOnlyFields [
-      "Description" "Alias" "MACAddressPolicy" "MACAddress" "NamePolicy" "Name" "OriginalName"
-      "MTUBytes" "BitsPerSecond" "Duplex" "AutoNegotiation" "WakeOnLan" "Port" "Advertise"
-      "TCPSegmentationOffload" "TCP6SegmentationOffload" "GenericSegmentationOffload"
-      "GenericReceiveOffload" "LargeReceiveOffload" "RxChannels" "TxChannels"
-      "OtherChannels" "CombinedChannels"
-    ])
-    (assertValueOneOf "MACAddressPolicy" ["persistent" "random" "none"])
-    (assertMacAddress "MACAddress")
-    (assertByteFormat "MTUBytes")
-    (assertByteFormat "BitsPerSecond")
-    (assertValueOneOf "Duplex" ["half" "full"])
-    (assertValueOneOf "AutoNegotiation" boolValues)
-    (assertValueOneOf "WakeOnLan" ["phy" "unicast" "multicast" "broadcast" "arp" "magic" "secureon" "off"])
-    (assertValueOneOf "Port" ["tp" "aui" "bnc" "mii" "fibre"])
-    (assertValueOneOf "TCPSegmentationOffload" boolValues)
-    (assertValueOneOf "TCP6SegmentationOffload" boolValues)
-    (assertValueOneOf "GenericSegmentationOffload" boolValues)
-    (assertValueOneOf "UDPSegmentationOffload" boolValues)
-    (assertValueOneOf "GenericReceiveOffload" boolValues)
-    (assertValueOneOf "LargeReceiveOffload" boolValues)
-    (assertInt "RxChannels")
-    (assertMinimum "RxChannels" 1)
-    (assertInt "TxChannels")
-    (assertMinimum "TxChannels" 1)
-    (assertInt "OtherChannels")
-    (assertMinimum "OtherChannels" 1)
-    (assertInt "CombinedChannels")
-    (assertMinimum "CombinedChannels" 1)
-  ];
-
-  checkNetdev = checkUnitConfig "Netdev" [
-    (assertOnlyFields [
-      "Description" "Name" "Kind" "MTUBytes" "MACAddress"
-    ])
-    (assertHasField "Name")
-    (assertHasField "Kind")
-    (assertValueOneOf "Kind" [
-      "bond" "bridge" "dummy" "gre" "gretap" "ip6gre" "ip6tnl" "ip6gretap" "ipip"
-      "ipvlan" "macvlan" "macvtap" "sit" "tap" "tun" "veth" "vlan" "vti" "vti6"
-      "vxlan" "geneve" "vrf" "vcan" "vxcan" "wireguard" "netdevsim" "xfrm"
-    ])
-    (assertByteFormat "MTUBytes")
-    (assertMacAddress "MACAddress")
-  ];
-
-  checkVRF = checkUnitConfig "VRF" [
-    (assertOnlyFields [ "Table" ])
-    (assertMinimum "Table" 0)
-  ];
+  check = {
+
+    link = {
+
+      sectionLink = checkUnitConfig "Link" [
+        (assertOnlyFields [
+          "Description"
+          "Alias"
+          "MACAddressPolicy"
+          "MACAddress"
+          "NamePolicy"
+          "Name"
+          "AlternativeNamesPolicy"
+          "AlternativeName"
+          "MTUBytes"
+          "BitsPerSecond"
+          "Duplex"
+          "AutoNegotiation"
+          "WakeOnLan"
+          "Port"
+          "Advertise"
+          "ReceiveChecksumOffload"
+          "TransmitChecksumOffload"
+          "TCPSegmentationOffload"
+          "TCP6SegmentationOffload"
+          "GenericSegmentationOffload"
+          "GenericReceiveOffload"
+          "LargeReceiveOffload"
+          "RxChannels"
+          "TxChannels"
+          "OtherChannels"
+          "CombinedChannels"
+          "RxBufferSize"
+          "TxBufferSize"
+        ])
+        (assertValueOneOf "MACAddressPolicy" ["persistent" "random" "none"])
+        (assertMacAddress "MACAddress")
+        (assertByteFormat "MTUBytes")
+        (assertByteFormat "BitsPerSecond")
+        (assertValueOneOf "Duplex" ["half" "full"])
+        (assertValueOneOf "AutoNegotiation" boolValues)
+        (assertValueOneOf "WakeOnLan" ["phy" "unicast" "multicast" "broadcast" "arp" "magic" "secureon" "off"])
+        (assertValueOneOf "Port" ["tp" "aui" "bnc" "mii" "fibre"])
+        (assertValueOneOf "ReceiveChecksumOffload" boolValues)
+        (assertValueOneOf "TransmitChecksumOffload" boolValues)
+        (assertValueOneOf "TCPSegmentationOffload" boolValues)
+        (assertValueOneOf "TCP6SegmentationOffload" boolValues)
+        (assertValueOneOf "GenericSegmentationOffload" boolValues)
+        (assertValueOneOf "GenericReceiveOffload" boolValues)
+        (assertValueOneOf "LargeReceiveOffload" boolValues)
+        (assertInt "RxChannels")
+        (assertRange "RxChannels" 1 4294967295)
+        (assertInt "TxChannels")
+        (assertRange "TxChannels" 1 4294967295)
+        (assertInt "OtherChannels")
+        (assertRange "OtherChannels" 1 4294967295)
+        (assertInt "CombinedChannels")
+        (assertRange "CombinedChannels" 1 4294967295)
+        (assertInt "RxBufferSize")
+        (assertInt "TxBufferSize")
+      ];
+    };
 
-  # NOTE The PrivateKey directive is missing on purpose here, please
-  # do not add it to this list. The nix store is world-readable let's
-  # refrain ourselves from providing a footgun.
-  checkWireGuard = checkUnitConfig "WireGuard" [
-    (assertOnlyFields [
-      "PrivateKeyFile" "ListenPort" "FwMark"
-    ])
-    # The following check won't work on nix <= 2.2
-    # see https://github.com/NixOS/nix/pull/2378
-    #
-    # Add this again when we'll have drop the
-    # nix < 2.2 support.
-    # (assertRange "FwMark" 1 4294967295)
-  ];
+    netdev = let
+
+      tunChecks = [
+        (assertOnlyFields [
+          "MultiQueue"
+          "PacketInfo"
+          "VNetHeader"
+          "User"
+          "Group"
+        ])
+        (assertValueOneOf "MultiQueue" boolValues)
+        (assertValueOneOf "PacketInfo" boolValues)
+        (assertValueOneOf "VNetHeader" boolValues)
+      ];
+    in {
+
+      sectionNetdev = checkUnitConfig "Netdev" [
+        (assertOnlyFields [
+          "Description"
+          "Name"
+          "Kind"
+          "MTUBytes"
+          "MACAddress"
+        ])
+        (assertHasField "Name")
+        (assertHasField "Kind")
+        (assertValueOneOf "Kind" [
+          "bond"
+          "bridge"
+          "dummy"
+          "gre"
+          "gretap"
+          "erspan"
+          "ip6gre"
+          "ip6tnl"
+          "ip6gretap"
+          "ipip"
+          "ipvlan"
+          "macvlan"
+          "macvtap"
+          "sit"
+          "tap"
+          "tun"
+          "veth"
+          "vlan"
+          "vti"
+          "vti6"
+          "vxlan"
+          "geneve"
+          "l2tp"
+          "macsec"
+          "vrf"
+          "vcan"
+          "vxcan"
+          "wireguard"
+          "netdevsim"
+          "nlmon"
+          "fou"
+          "xfrm"
+          "ifb"
+        ])
+        (assertByteFormat "MTUBytes")
+        (assertMacAddress "MACAddress")
+      ];
 
-  # NOTE The PresharedKey directive is missing on purpose here, please
-  # do not add it to this list. The nix store is world-readable,let's
-  # refrain ourselves from providing a footgun.
-  checkWireGuardPeer = checkUnitConfig "WireGuardPeer" [
-    (assertOnlyFields [
-      "PublicKey" "PresharedKeyFile" "AllowedIPs"
-      "Endpoint" "PersistentKeepalive"
-    ])
-    (assertRange "PersistentKeepalive" 1 65535)
-  ];
+      sectionVLAN = checkUnitConfig "VLAN" [
+        (assertOnlyFields [
+          "Id"
+          "GVRP"
+          "MVRP"
+          "LooseBinding"
+          "ReorderHeader"
+        ])
+        (assertInt "Id")
+        (assertRange "Id" 0 4094)
+        (assertValueOneOf "GVRP" boolValues)
+        (assertValueOneOf "MVRP" boolValues)
+        (assertValueOneOf "LooseBinding" boolValues)
+        (assertValueOneOf "ReorderHeader" boolValues)
+      ];
 
-  checkVlan = checkUnitConfig "VLAN" [
-    (assertOnlyFields ["Id" "GVRP" "MVRP" "LooseBinding" "ReorderHeader"])
-    (assertRange "Id" 0 4094)
-    (assertValueOneOf "GVRP" boolValues)
-    (assertValueOneOf "MVRP" boolValues)
-    (assertValueOneOf "LooseBinding" boolValues)
-    (assertValueOneOf "ReorderHeader" boolValues)
-  ];
+      sectionMACVLAN = checkUnitConfig "MACVLAN" [
+        (assertOnlyFields [
+          "Mode"
+        ])
+        (assertValueOneOf "Mode" ["private" "vepa" "bridge" "passthru"])
+      ];
 
-  checkMacvlan = checkUnitConfig "MACVLAN" [
-    (assertOnlyFields ["Mode"])
-    (assertValueOneOf "Mode" ["private" "vepa" "bridge" "passthru"])
-  ];
+      sectionVXLAN = checkUnitConfig "VXLAN" [
+        (assertOnlyFields [
+          "VNI"
+          "Remote"
+          "Local"
+          "Group"
+          "TOS"
+          "TTL"
+          "MacLearning"
+          "FDBAgeingSec"
+          "MaximumFDBEntries"
+          "ReduceARPProxy"
+          "L2MissNotification"
+          "L3MissNotification"
+          "RouteShortCircuit"
+          "UDPChecksum"
+          "UDP6ZeroChecksumTx"
+          "UDP6ZeroChecksumRx"
+          "RemoteChecksumTx"
+          "RemoteChecksumRx"
+          "GroupPolicyExtension"
+          "GenericProtocolExtension"
+          "DestinationPort"
+          "PortRange"
+          "FlowLabel"
+          "IPDoNotFragment"
+        ])
+        (assertInt "VNI")
+        (assertRange "VNI" 1 16777215)
+        (assertValueOneOf "MacLearning" boolValues)
+        (assertInt "MaximumFDBEntries")
+        (assertValueOneOf "ReduceARPProxy" boolValues)
+        (assertValueOneOf "L2MissNotification" boolValues)
+        (assertValueOneOf "L3MissNotification" boolValues)
+        (assertValueOneOf "RouteShortCircuit" boolValues)
+        (assertValueOneOf "UDPChecksum" boolValues)
+        (assertValueOneOf "UDP6ZeroChecksumTx" boolValues)
+        (assertValueOneOf "UDP6ZeroChecksumRx" boolValues)
+        (assertValueOneOf "RemoteChecksumTx" boolValues)
+        (assertValueOneOf "RemoteChecksumRx" boolValues)
+        (assertValueOneOf "GroupPolicyExtension" boolValues)
+        (assertValueOneOf "GenericProtocolExtension" boolValues)
+        (assertInt "FlowLabel")
+        (assertRange "FlowLabel" 0 1048575)
+        (assertValueOneOf "IPDoNotFragment" (boolValues + ["inherit"]))
+      ];
 
-  checkVxlan = checkUnitConfig "VXLAN" [
-    (assertOnlyFields [
-      "Id" "Remote" "Local" "TOS" "TTL" "MacLearning" "FDBAgeingSec"
-      "MaximumFDBEntries" "ReduceARPProxy" "L2MissNotification"
-      "L3MissNotification" "RouteShortCircuit" "UDPChecksum"
-      "UDP6ZeroChecksumTx" "UDP6ZeroChecksumRx" "RemoteChecksumTx"
-      "RemoteChecksumRx" "GroupPolicyExtension" "DestinationPort" "PortRange"
-      "FlowLabel"
-    ])
-    (assertRange "TTL" 0 255)
-    (assertValueOneOf "MacLearning" boolValues)
-    (assertValueOneOf "ReduceARPProxy" boolValues)
-    (assertValueOneOf "L2MissNotification" boolValues)
-    (assertValueOneOf "L3MissNotification" boolValues)
-    (assertValueOneOf "RouteShortCircuit" boolValues)
-    (assertValueOneOf "UDPChecksum" boolValues)
-    (assertValueOneOf "UDP6ZeroChecksumTx" boolValues)
-    (assertValueOneOf "UDP6ZeroChecksumRx" boolValues)
-    (assertValueOneOf "RemoteChecksumTx" boolValues)
-    (assertValueOneOf "RemoteChecksumRx" boolValues)
-    (assertValueOneOf "GroupPolicyExtension" boolValues)
-    (assertRange "FlowLabel" 0 1048575)
-  ];
+      sectionTunnel = checkUnitConfig "Tunnel" [
+        (assertOnlyFields [
+          "Local"
+          "Remote"
+          "TOS"
+          "TTL"
+          "DiscoverPathMTU"
+          "IPv6FlowLabel"
+          "CopyDSCP"
+          "EncapsulationLimit"
+          "Key"
+          "InputKey"
+          "OutputKey"
+          "Mode"
+          "Independent"
+          "AssignToLoopback"
+          "AllowLocalRemote"
+          "FooOverUDP"
+          "FOUDestinationPort"
+          "FOUSourcePort"
+          "Encapsulation"
+          "IPv6RapidDeploymentPrefix"
+          "ISATAP"
+          "SerializeTunneledPackets"
+          "ERSPANIndex"
+        ])
+        (assertInt "TTL")
+        (assertRange "TTL" 0 255)
+        (assertValueOneOf "DiscoverPathMTU" boolValues)
+        (assertValueOneOf "CopyDSCP" boolValues)
+        (assertValueOneOf "Mode" ["ip6ip6" "ipip6" "any"])
+        (assertValueOneOf "Independent" boolValues)
+        (assertValueOneOf "AssignToLoopback" boolValues)
+        (assertValueOneOf "AllowLocalRemote" boolValues)
+        (assertValueOneOf "FooOverUDP" boolValues)
+        (assertPort "FOUDestinationPort")
+        (assertPort "FOUSourcePort")
+        (assertValueOneOf "Encapsulation" ["FooOverUDP" "GenericUDPEncapsulation"])
+        (assertValueOneOf "ISATAP" boolValues)
+        (assertValueOneOf "SerializeTunneledPackets" boolValues)
+        (assertInt "ERSPANIndex")
+        (assertRange "ERSPANIndex" 1 1048575)
+      ];
 
-  checkTunnel = checkUnitConfig "Tunnel" [
-    (assertOnlyFields [
-      "Local" "Remote" "TOS" "TTL" "DiscoverPathMTU" "IPv6FlowLabel" "CopyDSCP"
-      "EncapsulationLimit" "Key" "InputKey" "OutputKey" "Mode" "Independent"
-      "AllowLocalRemote"
-    ])
-    (assertRange "TTL" 0 255)
-    (assertValueOneOf "DiscoverPathMTU" boolValues)
-    (assertValueOneOf "CopyDSCP" boolValues)
-    (assertValueOneOf "Mode" ["ip6ip6" "ipip6" "any"])
-    (assertValueOneOf "Independent" boolValues)
-    (assertValueOneOf "AllowLocalRemote" boolValues)
-  ];
+      sectionPeer = checkUnitConfig "Peer" [
+        (assertOnlyFields [
+          "Name"
+          "MACAddress"
+        ])
+        (assertMacAddress "MACAddress")
+      ];
 
-  checkPeer = checkUnitConfig "Peer" [
-    (assertOnlyFields ["Name" "MACAddress"])
-    (assertMacAddress "MACAddress")
-  ];
+      sectionTun = checkUnitConfig "Tun" tunChecks;
+
+      sectionTap = checkUnitConfig "Tap" tunChecks;
+
+      # NOTE The PrivateKey directive is missing on purpose here, please
+      # do not add it to this list. The nix store is world-readable let's
+      # refrain ourselves from providing a footgun.
+      sectionWireGuard = checkUnitConfig "WireGuard" [
+        (assertOnlyFields [
+          "PrivateKeyFile"
+          "ListenPort"
+          "FirewallMark"
+        ])
+        (assertInt "FirewallMark")
+        (assertRange "FirewallMark" 1 4294967295)
+      ];
 
-  tunTapChecks = [
-    (assertOnlyFields ["OneQueue" "MultiQueue" "PacketInfo" "VNetHeader" "User" "Group"])
-    (assertValueOneOf "OneQueue" boolValues)
-    (assertValueOneOf "MultiQueue" boolValues)
-    (assertValueOneOf "PacketInfo" boolValues)
-    (assertValueOneOf "VNetHeader" boolValues)
-  ];
+      # NOTE The PresharedKey directive is missing on purpose here, please
+      # do not add it to this list. The nix store is world-readable,let's
+      # refrain ourselves from providing a footgun.
+      sectionWireGuardPeer = checkUnitConfig "WireGuardPeer" [
+        (assertOnlyFields [
+          "PublicKey"
+          "PresharedKeyFile"
+          "AllowedIPs"
+          "Endpoint"
+          "PersistentKeepalive"
+        ])
+        (assertInt "PersistentKeepalive")
+        (assertRange "PersistentKeepalive" 0 65535)
+      ];
 
-  checkTun = checkUnitConfig "Tun" tunTapChecks;
-
-  checkTap = checkUnitConfig "Tap" tunTapChecks;
-
-  checkBond = checkUnitConfig "Bond" [
-    (assertOnlyFields [
-      "Mode" "TransmitHashPolicy" "LACPTransmitRate" "MIIMonitorSec"
-      "UpDelaySec" "DownDelaySec" "LearnPacketIntervalSec" "AdSelect"
-      "FailOverMACPolicy" "ARPValidate" "ARPIntervalSec" "ARPIPTargets"
-      "ARPAllTargets" "PrimaryReselectPolicy" "ResendIGMP" "PacketsPerSlave"
-      "GratuitousARP" "AllSlavesActive" "MinLinks"
-    ])
-    (assertValueOneOf "Mode" [
-      "balance-rr" "active-backup" "balance-xor"
-      "broadcast" "802.3ad" "balance-tlb" "balance-alb"
-    ])
-    (assertValueOneOf "TransmitHashPolicy" [
-      "layer2" "layer3+4" "layer2+3" "encap2+3" "encap3+4"
-    ])
-    (assertValueOneOf "LACPTransmitRate" ["slow" "fast"])
-    (assertValueOneOf "AdSelect" ["stable" "bandwidth" "count"])
-    (assertValueOneOf "FailOverMACPolicy" ["none" "active" "follow"])
-    (assertValueOneOf "ARPValidate" ["none" "active" "backup" "all"])
-    (assertValueOneOf "ARPAllTargets" ["any" "all"])
-    (assertValueOneOf "PrimaryReselectPolicy" ["always" "better" "failure"])
-    (assertRange "ResendIGMP" 0 255)
-    (assertRange "PacketsPerSlave" 0 65535)
-    (assertRange "GratuitousARP" 0 255)
-    (assertValueOneOf "AllSlavesActive" boolValues)
-  ];
+      sectionBond = checkUnitConfig "Bond" [
+        (assertOnlyFields [
+          "Mode"
+          "TransmitHashPolicy"
+          "LACPTransmitRate"
+          "MIIMonitorSec"
+          "UpDelaySec"
+          "DownDelaySec"
+          "LearnPacketIntervalSec"
+          "AdSelect"
+          "AdActorSystemPriority"
+          "AdUserPortKey"
+          "AdActorSystem"
+          "FailOverMACPolicy"
+          "ARPValidate"
+          "ARPIntervalSec"
+          "ARPIPTargets"
+          "ARPAllTargets"
+          "PrimaryReselectPolicy"
+          "ResendIGMP"
+          "PacketsPerSlave"
+          "GratuitousARP"
+          "AllSlavesActive"
+          "DynamicTransmitLoadBalancing"
+          "MinLinks"
+        ])
+        (assertValueOneOf "Mode" [
+          "balance-rr"
+          "active-backup"
+          "balance-xor"
+          "broadcast"
+          "802.3ad"
+          "balance-tlb"
+          "balance-alb"
+        ])
+        (assertValueOneOf "TransmitHashPolicy" [
+          "layer2"
+          "layer3+4"
+          "layer2+3"
+          "encap2+3"
+          "encap3+4"
+        ])
+        (assertValueOneOf "LACPTransmitRate" ["slow" "fast"])
+        (assertValueOneOf "AdSelect" ["stable" "bandwidth" "count"])
+        (assertInt "AdActorSystemPriority")
+        (assertRange "AdActorSystemPriority" 1 65535)
+        (assertInt "AdUserPortKey")
+        (assertRange "AdUserPortKey" 0 1023)
+        (assertValueOneOf "FailOverMACPolicy" ["none" "active" "follow"])
+        (assertValueOneOf "ARPValidate" ["none" "active" "backup" "all"])
+        (assertValueOneOf "ARPAllTargets" ["any" "all"])
+        (assertValueOneOf "PrimaryReselectPolicy" ["always" "better" "failure"])
+        (assertInt "ResendIGMP")
+        (assertRange "ResendIGMP" 0 255)
+        (assertInt "PacketsPerSlave")
+        (assertRange "PacketsPerSlave" 0 65535)
+        (assertInt "GratuitousARP")
+        (assertRange "GratuitousARP" 0 255)
+        (assertValueOneOf "AllSlavesActive" boolValues)
+        (assertValueOneOf "DynamicTransmitLoadBalancing" boolValues)
+        (assertInt "MinLinks")
+        (assertMinimum "MinLinks" 0)
+      ];
 
-  checkXfrm = checkUnitConfig "Xfrm" [
-    (assertOnlyFields [
-      "InterfaceId" "Independent"
-    ])
-    # The following check won't work on nix <= 2.2
-    # see https://github.com/NixOS/nix/pull/2378
-    #
-    # Add this again when we'll have drop the
-    # nix < 2.2 support.
-    # (assertRange "InterfaceId" 1 4294967295)
-    (assertValueOneOf "Independent" boolValues)
-  ];
+      sectionXfrm = checkUnitConfig "Xfrm" [
+        (assertOnlyFields [
+          "InterfaceId"
+          "Independent"
+        ])
+        (assertInt "InterfaceId")
+        (assertRange "InterfaceId" 1 4294967295)
+        (assertValueOneOf "Independent" boolValues)
+      ];
 
-  checkNetwork = checkUnitConfig "Network" [
-    (assertOnlyFields [
-      "Description" "DHCP" "DHCPServer" "LinkLocalAddressing" "IPv4LLRoute"
-      "IPv6Token" "LLMNR" "MulticastDNS" "DNSOverTLS" "DNSSEC"
-      "DNSSECNegativeTrustAnchors" "LLDP" "EmitLLDP" "BindCarrier" "Address"
-      "Gateway" "DNS" "Domains" "NTP" "IPForward" "IPMasquerade"
-      "IPv6PrivacyExtensions" "IPv6AcceptRA" "IPv6DuplicateAddressDetection"
-      "IPv6HopLimit" "IPv4ProxyARP" "IPv6ProxyNDP" "IPv6ProxyNDPAddress"
-      "IPv6PrefixDelegation" "IPv6MTUBytes" "Bridge" "Bond" "VRF" "VLAN"
-      "IPVLAN" "MACVLAN" "VXLAN" "Tunnel" "ActiveSlave" "PrimarySlave"
-      "ConfigureWithoutCarrier" "Xfrm" "KeepConfiguration"
-    ])
-    # Note: For DHCP the values both, none, v4, v6 are deprecated
-    (assertValueOneOf "DHCP" ["yes" "no" "ipv4" "ipv6" "both" "none" "v4" "v6"])
-    (assertValueOneOf "DHCPServer" boolValues)
-    (assertValueOneOf "LinkLocalAddressing" ["yes" "no" "ipv4" "ipv6" "ipv4-fallback" "fallback"])
-    (assertValueOneOf "IPv4LLRoute" boolValues)
-    (assertValueOneOf "LLMNR" ["yes" "resolve" "no"])
-    (assertValueOneOf "MulticastDNS" ["yes" "resolve" "no"])
-    (assertValueOneOf "DNSOverTLS" ["opportunistic" "no"])
-    (assertValueOneOf "DNSSEC" ["yes" "allow-downgrade" "no"])
-    (assertValueOneOf "LLDP" ["yes" "routers-only" "no"])
-    (assertValueOneOf "EmitLLDP" ["yes" "no" "nearest-bridge" "non-tpmr-bridge" "customer-bridge"])
-    (assertValueOneOf "IPForward" ["yes" "no" "ipv4" "ipv6"])
-    (assertValueOneOf "IPMasquerade" boolValues)
-    (assertValueOneOf "IPv6PrivacyExtensions" ["yes" "no" "prefer-public" "kernel"])
-    (assertValueOneOf "IPv6AcceptRA" boolValues)
-    (assertValueOneOf "IPv4ProxyARP" boolValues)
-    (assertValueOneOf "IPv6ProxyNDP" boolValues)
-    (assertValueOneOf "IPv6PrefixDelegation" (boolValues ++ [ "dhcpv6" "static" ]))
-    (assertValueOneOf "ActiveSlave" boolValues)
-    (assertValueOneOf "PrimarySlave" boolValues)
-    (assertValueOneOf "ConfigureWithoutCarrier" boolValues)
-    (assertValueOneOf "KeepConfiguration" (boolValues ++ ["static" "dhcp-on-stop" "dhcp"]))
-  ];
+      sectionVRF = checkUnitConfig "VRF" [
+        (assertOnlyFields [
+          "Table"
+        ])
+        (assertInt "Table")
+        (assertMinimum "Table" 0)
+      ];
+    };
 
-  checkAddress = checkUnitConfig "Address" [
-    (assertOnlyFields [
-      "Address" "Peer" "Broadcast" "Label" "PreferredLifetime" "Scope"
-      "HomeAddress" "DuplicateAddressDetection" "ManageTemporaryAddress"
-      "PrefixRoute" "AutoJoin"
-    ])
-    (assertHasField "Address")
-    (assertValueOneOf "PreferredLifetime" ["forever" "infinity" "0" 0])
-    (assertValueOneOf "HomeAddress" boolValues)
-    (assertValueOneOf "DuplicateAddressDetection" boolValues)
-    (assertValueOneOf "ManageTemporaryAddress" boolValues)
-    (assertValueOneOf "PrefixRoute" boolValues)
-    (assertValueOneOf "AutoJoin" boolValues)
-  ];
+    network = {
+
+      sectionLink = checkUnitConfig "Link" [
+        (assertOnlyFields [
+          "MACAddress"
+          "MTUBytes"
+          "ARP"
+          "Multicast"
+          "AllMulticast"
+          "Unmanaged"
+          "RequiredForOnline"
+        ])
+        (assertMacAddress "MACAddress")
+        (assertByteFormat "MTUBytes")
+        (assertValueOneOf "ARP" boolValues)
+        (assertValueOneOf "Multicast" boolValues)
+        (assertValueOneOf "AllMulticast" boolValues)
+        (assertValueOneOf "Unmanaged" boolValues)
+        (assertValueOneOf "RequiredForOnline" (boolValues ++ [
+          "missing"
+          "off"
+          "no-carrier"
+          "dormant"
+          "degraded-carrier"
+          "carrier"
+          "degraded"
+          "enslaved"
+          "routable"
+        ]))
+      ];
 
-  checkRoutingPolicyRule = checkUnitConfig "RoutingPolicyRule" [
-    (assertOnlyFields [
-      "TypeOfService" "From" "To" "FirewallMark" "Table" "Priority"
-      "IncomingInterface" "OutgoingInterface" "SourcePort" "DestinationPort"
-      "IPProtocol" "InvertRule" "Family"
-    ])
-    (assertRange "TypeOfService" 0 255)
-    # The following check won't work on nix <= 2.2
-    # see https://github.com/NixOS/nix/pull/2378
-    #
-    # Add this again when we'll have drop the
-    # nix < 2.2 support.
-    #  (assertRange "FirewallMark" 1 4294967295)
-    (assertInt "Priority")
-    (assertPort "SourcePort")
-    (assertPort "DestinationPort")
-    (assertValueOneOf "InvertRule" boolValues)
-    (assertValueOneOf "Family" ["ipv4" "ipv6" "both"])
-  ];
+      sectionNetwork = checkUnitConfig "Network" [
+        (assertOnlyFields [
+          "Description"
+          "DHCP"
+          "DHCPServer"
+          "LinkLocalAddressing"
+          "IPv4LLRoute"
+          "DefaultRouteOnDevice"
+          "IPv6Token"
+          "LLMNR"
+          "MulticastDNS"
+          "DNSOverTLS"
+          "DNSSEC"
+          "DNSSECNegativeTrustAnchors"
+          "LLDP"
+          "EmitLLDP"
+          "BindCarrier"
+          "Address"
+          "Gateway"
+          "DNS"
+          "Domains"
+          "DNSDefaultRoute"
+          "NTP"
+          "IPForward"
+          "IPMasquerade"
+          "IPv6PrivacyExtensions"
+          "IPv6AcceptRA"
+          "IPv6DuplicateAddressDetection"
+          "IPv6HopLimit"
+          "IPv4ProxyARP"
+          "IPv6ProxyNDP"
+          "IPv6ProxyNDPAddress"
+          "IPv6PrefixDelegation"
+          "IPv6MTUBytes"
+          "Bridge"
+          "Bond"
+          "VRF"
+          "VLAN"
+          "IPVLAN"
+          "MACVLAN"
+          "VXLAN"
+          "Tunnel"
+          "MACsec"
+          "ActiveSlave"
+          "PrimarySlave"
+          "ConfigureWithoutCarrier"
+          "IgnoreCarrierLoss"
+          "Xfrm"
+          "KeepConfiguration"
+        ])
+        # Note: For DHCP the values both, none, v4, v6 are deprecated
+        (assertValueOneOf "DHCP" ["yes" "no" "ipv4" "ipv6"])
+        (assertValueOneOf "DHCPServer" boolValues)
+        (assertValueOneOf "LinkLocalAddressing" ["yes" "no" "ipv4" "ipv6" "fallback" "ipv4-fallback"])
+        (assertValueOneOf "IPv4LLRoute" boolValues)
+        (assertValueOneOf "DefaultRouteOnDevice" boolValues)
+        (assertValueOneOf "LLMNR" (boolValues ++ ["resolve"]))
+        (assertValueOneOf "MulticastDNS" (boolValues ++ ["resolve"]))
+        (assertValueOneOf "DNSOverTLS" (boolValues ++ ["opportunistic"]))
+        (assertValueOneOf "DNSSEC" (boolValues ++ ["allow-downgrade"]))
+        (assertValueOneOf "LLDP" (boolValues ++ ["routers-only"]))
+        (assertValueOneOf "EmitLLDP" (boolValues ++ ["nearest-bridge" "non-tpmr-bridge" "customer-bridge"]))
+        (assertValueOneOf "DNSDefaultRoute" boolValues)
+        (assertValueOneOf "IPForward" (boolValues ++ ["ipv4" "ipv6"]))
+        (assertValueOneOf "IPMasquerade" boolValues)
+        (assertValueOneOf "IPv6PrivacyExtensions" (boolValues ++ ["prefer-public" "kernel"]))
+        (assertValueOneOf "IPv6AcceptRA" boolValues)
+        (assertInt "IPv6DuplicateAddressDetection")
+        (assertMinimum "IPv6DuplicateAddressDetection" 0)
+        (assertInt "IPv6HopLimit")
+        (assertMinimum "IPv6HopLimit" 0)
+        (assertValueOneOf "IPv4ProxyARP" boolValues)
+        (assertValueOneOf "IPv6ProxyNDP" boolValues)
+        (assertValueOneOf "IPv6PrefixDelegation" ["static" "dhcpv6" "yes" "false"])
+        (assertByteFormat "IPv6MTUBytes")
+        (assertValueOneOf "ActiveSlave" boolValues)
+        (assertValueOneOf "PrimarySlave" boolValues)
+        (assertValueOneOf "ConfigureWithoutCarrier" boolValues)
+        (assertValueOneOf "IgnoreCarrierLoss" boolValues)
+        (assertValueOneOf "KeepConfiguration" (boolValues ++ ["static" "dhcp-on-stop" "dhcp"]))
+      ];
 
-  checkRoute = checkUnitConfig "Route" [
-    (assertOnlyFields [
-      "Gateway" "GatewayOnLink" "Destination" "Source" "Metric"
-      "IPv6Preference" "Scope" "PreferredSource" "Table" "Protocol" "Type"
-      "InitialCongestionWindow" "InitialAdvertisedReceiveWindow" "QuickAck"
-      "MTUBytes"
-    ])
-  ];
+      sectionAddress = checkUnitConfig "Address" [
+        (assertOnlyFields [
+          "Address"
+          "Peer"
+          "Broadcast"
+          "Label"
+          "PreferredLifetime"
+          "Scope"
+          "HomeAddress"
+          "DuplicateAddressDetection"
+          "ManageTemporaryAddress"
+          "AddPrefixRoute"
+          "AutoJoin"
+        ])
+        (assertHasField "Address")
+        (assertValueOneOf "PreferredLifetime" ["forever" "infinity" "0" 0])
+        (assertValueOneOf "HomeAddress" boolValues)
+        (assertValueOneOf "DuplicateAddressDetection" ["ipv4" "ipv6" "both" "none"])
+        (assertValueOneOf "ManageTemporaryAddress" boolValues)
+        (assertValueOneOf "AddPrefixRoute" boolValues)
+        (assertValueOneOf "AutoJoin" boolValues)
+      ];
 
-  checkDhcpV4 = checkUnitConfig "DHCPv4" [
-    (assertOnlyFields [
-      "UseDNS" "RoutesToDNS" "UseNTP" "UseMTU" "Anonymize" "SendHostname" "UseHostname"
-      "Hostname" "UseDomains" "UseRoutes" "UseTimezone"
-      "ClientIdentifier" "VendorClassIdentifier" "UserClass" "MaxAttempts"
-      "DUIDType" "DUIDRawData" "IAID" "RequestBroadcast" "RouteMetric" "RouteTable"
-      "ListenPort" "SendRelease"
-    ])
-    (assertValueOneOf "UseDNS" boolValues)
-    (assertValueOneOf "RoutesToDNS" boolValues)
-    (assertValueOneOf "UseNTP" boolValues)
-    (assertValueOneOf "UseMTU" boolValues)
-    (assertValueOneOf "Anonymize" boolValues)
-    (assertValueOneOf "SendHostname" boolValues)
-    (assertValueOneOf "UseHostname" boolValues)
-    (assertValueOneOf "UseDomains" ["yes" "no" "route"])
-    (assertValueOneOf "UseRoutes" boolValues)
-    (assertValueOneOf "UseTimezone" boolValues)
-    (assertMinimum "MaxAttempts" 0)
-    (assertValueOneOf "RequestBroadcast" boolValues)
-    (assertInt "RouteTable")
-    (assertMinimum "RouteTable" 0)
-    (assertValueOneOf "SendRelease" boolValues)
-  ];
+      sectionRoutingPolicyRule = checkUnitConfig "RoutingPolicyRule" [
+        (assertOnlyFields [
+          "TypeOfService"
+          "From"
+          "To"
+          "FirewallMark"
+          "Table"
+          "Priority"
+          "IncomingInterface"
+          "OutgoingInterface"
+          "SourcePort"
+          "DestinationPort"
+          "IPProtocol"
+          "InvertRule"
+          "Family"
+          "User"
+          "SuppressPrefixLength"
+        ])
+        (assertInt "TypeOfService")
+        (assertRange "TypeOfService" 0 255)
+        (assertInt "FirewallMark")
+        (assertRange "FirewallMark" 1 4294967295)
+        (assertInt "Priority")
+        (assertPort "SourcePort")
+        (assertPort "DestinationPort")
+        (assertValueOneOf "InvertRule" boolValues)
+        (assertValueOneOf "Family" ["ipv4" "ipv6" "both"])
+        (assertInt "SuppressPrefixLength")
+        (assertRange "SuppressPrefixLength" 0 128)
+      ];
 
-  checkDhcpV6 = checkUnitConfig "DHCPv6" [
-    (assertOnlyFields [
-      "UseDns" "UseNTP" "RapidCommit" "ForceDHCPv6PDOtherInformation"
-      "PrefixDelegationHint"
-    ])
-    (assertValueOneOf "UseDNS" boolValues)
-    (assertValueOneOf "UseNTP" boolValues)
-    (assertValueOneOf "RapidCommit" boolValues)
-    (assertValueOneOf "ForceDHCPv6PDOtherInformation" boolValues)
-  ];
+      sectionRoute = checkUnitConfig "Route" [
+        (assertOnlyFields [
+          "Gateway"
+          "GatewayOnLink"
+          "Destination"
+          "Source"
+          "Metric"
+          "IPv6Preference"
+          "Scope"
+          "PreferredSource"
+          "Table"
+          "Protocol"
+          "Type"
+          "InitialCongestionWindow"
+          "InitialAdvertisedReceiveWindow"
+          "QuickAck"
+          "FastOpenNoCookie"
+          "TTLPropagate"
+          "MTUBytes"
+          "IPServiceType"
+          "MultiPathRoute"
+        ])
+        (assertValueOneOf "GatewayOnLink" boolValues)
+        (assertInt "Metric")
+        (assertValueOneOf "IPv6Preference" ["low" "medium" "high"])
+        (assertValueOneOf "Scope" ["global" "site" "link" "host" "nowhere"])
+        (assertValueOneOf "Type" [
+          "unicast"
+          "local"
+          "broadcast"
+          "anycast"
+          "multicast"
+          "blackhole"
+          "unreachable"
+          "prohibit"
+          "throw"
+          "nat"
+          "xresolve"
+        ])
+        (assertValueOneOf "QuickAck" boolValues)
+        (assertValueOneOf "FastOpenNoCookie" boolValues)
+        (assertValueOneOf "TTLPropagate" boolValues)
+        (assertByteFormat "MTUBytes")
+        (assertValueOneOf "IPServiceType" ["CS6" "CS4"])
+      ];
 
-  checkIpv6PrefixDelegation = checkUnitConfig "IPv6PrefixDelegation" [
-    (assertOnlyFields [
-      "Managed"  "OtherInformation"  "RouterLifetimeSec"
-      "RouterPreference"  "EmitDNS"  "DNS"  "EmitDomains"  "Domains"
-      "DNSLifetimeSec"
-    ])
-    (assertValueOneOf "Managed" boolValues)
-    (assertValueOneOf "OtherInformation" boolValues)
-    (assertValueOneOf "RouterPreference" ["high" "medium" "low" "normal" "default"])
-    (assertValueOneOf "EmitDNS" boolValues)
-    (assertValueOneOf "EmitDomains" boolValues)
-    (assertMinimum "DNSLifetimeSec" 0)
-  ];
+      sectionDHCPv4 = checkUnitConfig "DHCPv4" [
+        (assertOnlyFields [
+          "UseDNS"
+          "RoutesToDNS"
+          "UseNTP"
+          "UseSIP"
+          "UseMTU"
+          "Anonymize"
+          "SendHostname"
+          "UseHostname"
+          "Hostname"
+          "UseDomains"
+          "UseRoutes"
+          "UseTimezone"
+          "ClientIdentifier"
+          "VendorClassIdentifier"
+          "UserClass"
+          "MaxAttempts"
+          "DUIDType"
+          "DUIDRawData"
+          "IAID"
+          "RequestBroadcast"
+          "RouteMetric"
+          "RouteTable"
+          "RouteMTUBytes"
+          "ListenPort"
+          "SendRelease"
+          "SendDecline"
+          "BlackList"
+          "RequestOptions"
+          "SendOption"
+        ])
+        (assertValueOneOf "UseDNS" boolValues)
+        (assertValueOneOf "RoutesToDNS" boolValues)
+        (assertValueOneOf "UseNTP" boolValues)
+        (assertValueOneOf "UseSIP" boolValues)
+        (assertValueOneOf "UseMTU" boolValues)
+        (assertValueOneOf "Anonymize" boolValues)
+        (assertValueOneOf "SendHostname" boolValues)
+        (assertValueOneOf "UseHostname" boolValues)
+        (assertValueOneOf "UseDomains" (boolValues ++ ["route"]))
+        (assertValueOneOf "UseRoutes" boolValues)
+        (assertValueOneOf "UseTimezone" boolValues)
+        (assertValueOneOf "ClientIdentifier" ["mac" "duid" "duid-only"])
+        (assertInt "IAID")
+        (assertValueOneOf "RequestBroadcast" boolValues)
+        (assertInt "RouteMetric")
+        (assertInt "RouteTable")
+        (assertRange "RouteTable" 0 4294967295)
+        (assertByteFormat "RouteMTUBytes")
+        (assertPort "ListenPort")
+        (assertValueOneOf "SendRelease" boolValues)
+        (assertValueOneOf "SendDecline" boolValues)
+      ];
 
-  checkIpv6Prefix = checkUnitConfig "IPv6Prefix" [
-    (assertOnlyFields [
-      "AddressAutoconfiguration"  "OnLink"  "Prefix"
-      "PreferredLifetimeSec" "ValidLifetimeSec"
-    ])
-    (assertValueOneOf "AddressAutoconfiguration" boolValues)
-    (assertValueOneOf "OnLink" boolValues)
-    (assertMinimum "PreferredLifetimeSec" 0)
-    (assertMinimum "ValidLifetimeSec" 0)
-  ];
+      sectionDHCPv6 = checkUnitConfig "DHCPv6" [
+        (assertOnlyFields [
+          "UseDNS"
+          "UseNTP"
+          "RapidCommit"
+          "ForceDHCPv6PDOtherInformation"
+          "PrefixDelegationHint"
+        ])
+        (assertValueOneOf "UseDNS" boolValues)
+        (assertValueOneOf "UseNTP" boolValues)
+        (assertValueOneOf "RapidCommit" boolValues)
+        (assertValueOneOf "ForceDHCPv6PDOtherInformation" boolValues)
+      ];
 
+      sectionDHCPServer = checkUnitConfig "DHCPServer" [
+        (assertOnlyFields [
+          "PoolOffset"
+          "PoolSize"
+          "DefaultLeaseTimeSec"
+          "MaxLeaseTimeSec"
+          "EmitDNS"
+          "DNS"
+          "EmitNTP"
+          "NTP"
+          "EmitSIP"
+          "SIP"
+          "EmitRouter"
+          "EmitTimezone"
+          "Timezone"
+          "SendOption"
+        ])
+        (assertInt "PoolOffset")
+        (assertMinimum "PoolOffset" 0)
+        (assertInt "PoolSize")
+        (assertMinimum "PoolSize" 0)
+        (assertValueOneOf "EmitDNS" boolValues)
+        (assertValueOneOf "EmitNTP" boolValues)
+        (assertValueOneOf "EmitSIP" boolValues)
+        (assertValueOneOf "EmitRouter" boolValues)
+        (assertValueOneOf "EmitTimezone" boolValues)
+      ];
 
-  checkDhcpServer = checkUnitConfig "DHCPServer" [
-    (assertOnlyFields [
-      "PoolOffset" "PoolSize" "DefaultLeaseTimeSec" "MaxLeaseTimeSec"
-      "EmitDNS" "DNS" "EmitNTP" "NTP" "EmitRouter" "EmitTimezone" "Timezone"
-    ])
-    (assertValueOneOf "EmitDNS" boolValues)
-    (assertValueOneOf "EmitNTP" boolValues)
-    (assertValueOneOf "EmitRouter" boolValues)
-    (assertValueOneOf "EmitTimezone" boolValues)
-  ];
+      sectionIPv6PrefixDelegation = checkUnitConfig "IPv6PrefixDelegation" [
+        (assertOnlyFields [
+          "Managed"
+          "OtherInformation"
+          "RouterLifetimeSec"
+          "RouterPreference"
+          "EmitDNS"
+          "DNS"
+          "EmitDomains"
+          "Domains"
+          "DNSLifetimeSec"
+        ])
+        (assertValueOneOf "Managed" boolValues)
+        (assertValueOneOf "OtherInformation" boolValues)
+        (assertValueOneOf "RouterPreference" ["high" "medium" "low" "normal" "default"])
+        (assertValueOneOf "EmitDNS" boolValues)
+        (assertValueOneOf "EmitDomains" boolValues)
+      ];
 
-  # .network files have a [Link] section with different options than in .netlink files
-  checkNetworkLink = checkUnitConfig "Link" [
-    (assertOnlyFields [
-      "MACAddress" "MTUBytes" "ARP" "Multicast" "Unmanaged" "RequiredForOnline"
-    ])
-    (assertMacAddress "MACAddress")
-    (assertByteFormat "MTUBytes")
-    (assertValueOneOf "ARP" boolValues)
-    (assertValueOneOf "Multicast" boolValues)
-    (assertValueOneOf "Unmanaged" boolValues)
-    (assertValueOneOf "RequiredForOnline" (boolValues ++ ["off" "no-carrier" "dormant" "degraded-carrier" "carrier" "degraded" "enslaved" "routable"]))
-  ];
+      sectionIPv6Prefix = checkUnitConfig "IPv6Prefix" [
+        (assertOnlyFields [
+          "AddressAutoconfiguration"
+          "OnLink"
+          "Prefix"
+          "PreferredLifetimeSec"
+          "ValidLifetimeSec"
+        ])
+        (assertValueOneOf "AddressAutoconfiguration" boolValues)
+        (assertValueOneOf "OnLink" boolValues)
+      ];
 
+    };
+  };
 
   commonNetworkOptions = {
 
@@ -406,7 +761,7 @@ let
     linkConfig = mkOption {
       default = {};
       example = { MACAddress = "00:ff:ee:aa:cc:dd"; };
-      type = types.addCheck (types.attrsOf unitOption) checkLink;
+      type = types.addCheck (types.attrsOf unitOption) check.link.sectionLink;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[Link]</literal> section of the unit.  See
@@ -417,12 +772,28 @@ let
 
   };
 
+  wireguardPeerOptions = {
+    options = {
+      wireguardPeerConfig = mkOption {
+        default = {};
+        example = { };
+        type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionWireGuardPeer;
+        description = ''
+          Each attribute in this set specifies an option in the
+          <literal>[WireGuardPeer]</literal> section of the unit.  See
+          <citerefentry><refentrytitle>systemd.network</refentrytitle>
+          <manvolnum>5</manvolnum></citerefentry> for details.
+        '';
+      };
+    };
+  };
+
   netdevOptions = commonNetworkOptions // {
 
     netdevConfig = mkOption {
       default = {};
       example = { Name = "mybridge"; Kind = "bridge"; };
-      type = types.addCheck (types.attrsOf unitOption) checkNetdev;
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionNetdev;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[Netdev]</literal> section of the unit.  See
@@ -431,65 +802,10 @@ let
       '';
     };
 
-    vrfConfig = mkOption {
-      default = {};
-      example = { Table = 2342; };
-      type = types.addCheck (types.attrsOf unitOption) checkVRF;
-      description = ''
-        Each attribute in this set specifies an option in the
-        <literal>[VRF]</literal> section of the unit. See
-        <citerefentry><refentrytitle>systemd.netdev</refentrytitle>
-        <manvolnum>5</manvolnum></citerefentry> for details.
-        A detailed explanation about how VRFs work can be found in the
-        <link xlink:href="https://www.kernel.org/doc/Documentation/networking/vrf.txt">kernel
-        docs</link>.
-      '';
-    };
-
-    wireguardConfig = mkOption {
-      default = {};
-      example = {
-        PrivateKeyFile = "/etc/wireguard/secret.key";
-        ListenPort = 51820;
-        FwMark = 42;
-      };
-      type = types.addCheck (types.attrsOf unitOption) checkWireGuard;
-      description = ''
-        Each attribute in this set specifies an option in the
-        <literal>[WireGuard]</literal> section of the unit. See
-        <citerefentry><refentrytitle>systemd.netdev</refentrytitle>
-        <manvolnum>5</manvolnum></citerefentry> for details.
-        Use <literal>PrivateKeyFile</literal> instead of
-        <literal>PrivateKey</literal>: the nix store is
-        world-readable.
-      '';
-    };
-
-    wireguardPeers = mkOption {
-      default = [];
-      example = [ { wireguardPeerConfig={
-        Endpoint = "192.168.1.1:51820";
-        PublicKey = "27s0OvaBBdHoJYkH9osZpjpgSOVNw+RaKfboT/Sfq0g=";
-        PresharedKeyFile = "/etc/wireguard/psk.key";
-        AllowedIPs = [ "10.0.0.1/32" ];
-        PersistentKeepalive = 15;
-      };}];
-      type = with types; listOf (submodule wireguardPeerOptions);
-      description = ''
-        Each item in this array specifies an option in the
-        <literal>[WireGuardPeer]</literal> section of the unit. See
-        <citerefentry><refentrytitle>systemd.netdev</refentrytitle>
-        <manvolnum>5</manvolnum></citerefentry> for details.
-        Use <literal>PresharedKeyFile</literal> instead of
-        <literal>PresharedKey</literal>: the nix store is
-        world-readable.
-      '';
-    };
-
     vlanConfig = mkOption {
       default = {};
-      example = { Id = "4"; };
-      type = types.addCheck (types.attrsOf unitOption) checkVlan;
+      example = { Id = 4; };
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionVLAN;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[VLAN]</literal> section of the unit.  See
@@ -501,7 +817,7 @@ let
     macvlanConfig = mkOption {
       default = {};
       example = { Mode = "private"; };
-      type = types.addCheck (types.attrsOf unitOption) checkMacvlan;
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionMACVLAN;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[MACVLAN]</literal> section of the unit.  See
@@ -513,7 +829,7 @@ let
     vxlanConfig = mkOption {
       default = {};
       example = { Id = "4"; };
-      type = types.addCheck (types.attrsOf unitOption) checkVxlan;
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionVXLAN;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[VXLAN]</literal> section of the unit.  See
@@ -525,7 +841,7 @@ let
     tunnelConfig = mkOption {
       default = {};
       example = { Remote = "192.168.1.1"; };
-      type = types.addCheck (types.attrsOf unitOption) checkTunnel;
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionTunnel;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[Tunnel]</literal> section of the unit.  See
@@ -537,7 +853,7 @@ let
     peerConfig = mkOption {
       default = {};
       example = { Name = "veth2"; };
-      type = types.addCheck (types.attrsOf unitOption) checkPeer;
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionPeer;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[Peer]</literal> section of the unit.  See
@@ -549,7 +865,7 @@ let
     tunConfig = mkOption {
       default = {};
       example = { User = "openvpn"; };
-      type = types.addCheck (types.attrsOf unitOption) checkTun;
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionTun;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[Tun]</literal> section of the unit.  See
@@ -561,7 +877,7 @@ let
     tapConfig = mkOption {
       default = {};
       example = { User = "openvpn"; };
-      type = types.addCheck (types.attrsOf unitOption) checkTap;
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionTap;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[Tap]</literal> section of the unit.  See
@@ -570,10 +886,50 @@ let
       '';
     };
 
+    wireguardConfig = mkOption {
+      default = {};
+      example = {
+        PrivateKeyFile = "/etc/wireguard/secret.key";
+        ListenPort = 51820;
+        FwMark = 42;
+      };
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionWireGuard;
+      description = ''
+        Each attribute in this set specifies an option in the
+        <literal>[WireGuard]</literal> section of the unit. See
+        <citerefentry><refentrytitle>systemd.netdev</refentrytitle>
+        <manvolnum>5</manvolnum></citerefentry> for details.
+        Use <literal>PrivateKeyFile</literal> instead of
+        <literal>PrivateKey</literal>: the nix store is
+        world-readable.
+      '';
+    };
+
+    wireguardPeers = mkOption {
+      default = [];
+      example = [ { wireguardPeerConfig={
+        Endpoint = "192.168.1.1:51820";
+        PublicKey = "27s0OvaBBdHoJYkH9osZpjpgSOVNw+RaKfboT/Sfq0g=";
+        PresharedKeyFile = "/etc/wireguard/psk.key";
+        AllowedIPs = [ "10.0.0.1/32" ];
+        PersistentKeepalive = 15;
+      };}];
+      type = with types; listOf (submodule wireguardPeerOptions);
+      description = ''
+        Each item in this array specifies an option in the
+        <literal>[WireGuardPeer]</literal> section of the unit. See
+        <citerefentry><refentrytitle>systemd.netdev</refentrytitle>
+        <manvolnum>5</manvolnum></citerefentry> for details.
+        Use <literal>PresharedKeyFile</literal> instead of
+        <literal>PresharedKey</literal>: the nix store is
+        world-readable.
+      '';
+    };
+
     bondConfig = mkOption {
       default = {};
       example = { Mode = "802.3ad"; };
-      type = types.addCheck (types.attrsOf unitOption) checkBond;
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionBond;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[Bond]</literal> section of the unit.  See
@@ -585,7 +941,7 @@ let
     xfrmConfig = mkOption {
       default = {};
       example = { InterfaceId = 1; };
-      type = types.addCheck (types.attrsOf unitOption) checkXfrm;
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionXfrm;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[Xfrm]</literal> section of the unit.  See
@@ -594,6 +950,21 @@ let
       '';
     };
 
+    vrfConfig = mkOption {
+      default = {};
+      example = { Table = 2342; };
+      type = types.addCheck (types.attrsOf unitOption) check.netdev.sectionVRF;
+      description = ''
+        Each attribute in this set specifies an option in the
+        <literal>[VRF]</literal> section of the unit. See
+        <citerefentry><refentrytitle>systemd.netdev</refentrytitle>
+        <manvolnum>5</manvolnum></citerefentry> for details.
+        A detailed explanation about how VRFs work can be found in the
+        <link xlink:href="https://www.kernel.org/doc/Documentation/networking/vrf.txt">kernel
+        docs</link>.
+      '';
+    };
+
   };
 
   addressOptions = {
@@ -601,7 +972,7 @@ let
       addressConfig = mkOption {
         default = {};
         example = { Address = "192.168.0.100/24"; };
-        type = types.addCheck (types.attrsOf unitOption) checkAddress;
+        type = types.addCheck (types.attrsOf unitOption) check.network.sectionAddress;
         description = ''
           Each attribute in this set specifies an option in the
           <literal>[Address]</literal> section of the unit.  See
@@ -617,7 +988,7 @@ let
       routingPolicyRuleConfig = mkOption {
         default = { };
         example = { routingPolicyRuleConfig = { Table = 10; IncomingInterface = "eth1"; Family = "both"; } ;};
-        type = types.addCheck (types.attrsOf unitOption) checkRoutingPolicyRule;
+        type = types.addCheck (types.attrsOf unitOption) check.network.sectionRoutingPolicyRule;
         description = ''
           Each attribute in this set specifies an option in the
           <literal>[RoutingPolicyRule]</literal> section of the unit.  See
@@ -633,7 +1004,7 @@ let
       routeConfig = mkOption {
         default = {};
         example = { Gateway = "192.168.0.1"; };
-        type = types.addCheck (types.attrsOf unitOption) checkRoute;
+        type = types.addCheck (types.attrsOf unitOption) check.network.sectionRoute;
         description = ''
           Each attribute in this set specifies an option in the
           <literal>[Route]</literal> section of the unit.  See
@@ -644,28 +1015,12 @@ let
     };
   };
 
-  wireguardPeerOptions = {
-    options = {
-      wireguardPeerConfig = mkOption {
-        default = {};
-        example = { };
-        type = types.addCheck (types.attrsOf unitOption) checkWireGuardPeer;
-        description = ''
-          Each attribute in this set specifies an option in the
-          <literal>[WireGuardPeer]</literal> section of the unit.  See
-          <citerefentry><refentrytitle>systemd.network</refentrytitle>
-          <manvolnum>5</manvolnum></citerefentry> for details.
-        '';
-      };
-    };
-  };
-
   ipv6PrefixOptions = {
     options = {
       ipv6PrefixConfig = mkOption {
         default = {};
         example = { Prefix = "fd00::/64"; };
-        type = types.addCheck (types.attrsOf unitOption) checkIpv6Prefix;
+        type = types.addCheck (types.attrsOf unitOption) check.network.sectionIPv6Prefix;
         description = ''
           Each attribute in this set specifies an option in the
           <literal>[IPv6Prefix]</literal> section of the unit.  See
@@ -676,13 +1031,24 @@ let
     };
   };
 
-
   networkOptions = commonNetworkOptions // {
 
+    linkConfig = mkOption {
+      default = {};
+      example = { Unmanaged = true; };
+      type = types.addCheck (types.attrsOf unitOption) check.network.sectionLink;
+      description = ''
+        Each attribute in this set specifies an option in the
+        <literal>[Link]</literal> section of the unit.  See
+        <citerefentry><refentrytitle>systemd.network</refentrytitle>
+        <manvolnum>5</manvolnum></citerefentry> for details.
+      '';
+    };
+
     networkConfig = mkOption {
       default = {};
       example = { Description = "My Network"; };
-      type = types.addCheck (types.attrsOf unitOption) checkNetwork;
+      type = types.addCheck (types.attrsOf unitOption) check.network.sectionNetwork;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[Network]</literal> section of the unit.  See
@@ -701,7 +1067,7 @@ let
     dhcpV4Config = mkOption {
       default = {};
       example = { UseDNS = true; UseRoutes = true; };
-      type = types.addCheck (types.attrsOf unitOption) checkDhcpV4;
+      type = types.addCheck (types.attrsOf unitOption) check.network.sectionDHCPv4;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[DHCPv4]</literal> section of the unit.  See
@@ -713,7 +1079,7 @@ let
     dhcpV6Config = mkOption {
       default = {};
       example = { UseDNS = true; UseRoutes = true; };
-      type = types.addCheck (types.attrsOf unitOption) checkDhcpV6;
+      type = types.addCheck (types.attrsOf unitOption) check.network.sectionDHCPv6;
       description = ''
         Each attribute in this set specifies an option in the
         <literal>[DHCPv6]</literal> section of the unit.  See
@@ -722,48 +1088,36 @@ let
       '';
     };
 
-    ipv6PrefixDelegationConfig = mkOption {
+    dhcpServerConfig = mkOption {
       default = {};
-      example = { EmitDNS = true; Managed = true; OtherInformation = true; };
-      type = types.addCheck (types.attrsOf unitOption) checkIpv6PrefixDelegation;
+      example = { PoolOffset = 50; EmitDNS = false; };
+      type = types.addCheck (types.attrsOf unitOption) check.network.sectionDHCPServer;
       description = ''
         Each attribute in this set specifies an option in the
-        <literal>[IPv6PrefixDelegation]</literal> section of the unit.  See
-        <citerefentry><refentrytitle>systemd.network</refentrytitle>
-        <manvolnum>5</manvolnum></citerefentry> for details.
-      '';
-    };
-
-    ipv6Prefixes = mkOption {
-      default = [];
-      example = { AddressAutoconfiguration = true; OnLink = true; };
-      type = with types; listOf (submodule ipv6PrefixOptions);
-      description = ''
-        A list of ipv6Prefix sections to be added to the unit.  See
+        <literal>[DHCPServer]</literal> section of the unit.  See
         <citerefentry><refentrytitle>systemd.network</refentrytitle>
         <manvolnum>5</manvolnum></citerefentry> for details.
       '';
     };
 
-    dhcpServerConfig = mkOption {
+    ipv6PrefixDelegationConfig = mkOption {
       default = {};
-      example = { PoolOffset = 50; EmitDNS = false; };
-      type = types.addCheck (types.attrsOf unitOption) checkDhcpServer;
+      example = { EmitDNS = true; Managed = true; OtherInformation = true; };
+      type = types.addCheck (types.attrsOf unitOption) check.network.sectionIPv6PrefixDelegation;
       description = ''
         Each attribute in this set specifies an option in the
-        <literal>[DHCPServer]</literal> section of the unit.  See
+        <literal>[IPv6PrefixDelegation]</literal> section of the unit.  See
         <citerefentry><refentrytitle>systemd.network</refentrytitle>
         <manvolnum>5</manvolnum></citerefentry> for details.
       '';
     };
 
-    linkConfig = mkOption {
-      default = {};
-      example = { Unmanaged = true; };
-      type = types.addCheck (types.attrsOf unitOption) checkNetworkLink;
+    ipv6Prefixes = mkOption {
+      default = [];
+      example = { AddressAutoconfiguration = true; OnLink = true; };
+      type = with types; listOf (submodule ipv6PrefixOptions);
       description = ''
-        Each attribute in this set specifies an option in the
-        <literal>[Link]</literal> section of the unit.  See
+        A list of ipv6Prefix sections to be added to the unit.  See
         <citerefentry><refentrytitle>systemd.network</refentrytitle>
         <manvolnum>5</manvolnum></citerefentry> for details.
       '';
@@ -958,160 +1312,162 @@ let
     };
   };
 
-  commonMatchText = def: optionalString (def.matchConfig != {}) ''
+  commonMatchText = def: optionalString (def.matchConfig != { }) ''
     [Match]
     ${attrsToSection def.matchConfig}
   '';
 
   linkToUnit = name: def:
     { inherit (def) enable;
-      text = commonMatchText def +
-        ''
+      text = commonMatchText def
+        + ''
           [Link]
           ${attrsToSection def.linkConfig}
-
-          ${def.extraConfig}
-        '';
+        ''
+        + def.extraConfig;
     };
 
   netdevToUnit = name: def:
     { inherit (def) enable;
-      text = commonMatchText def +
-        ''
+      text = commonMatchText def
+        + ''
           [NetDev]
           ${attrsToSection def.netdevConfig}
-
-          ${optionalString (def.vlanConfig != { }) ''
-            [VLAN]
-            ${attrsToSection def.vlanConfig}
-
-          ''}
-          ${optionalString (def.macvlanConfig != { }) ''
-            [MACVLAN]
-            ${attrsToSection def.macvlanConfig}
-
-          ''}
-          ${optionalString (def.vxlanConfig != { }) ''
-            [VXLAN]
-            ${attrsToSection def.vxlanConfig}
-
-          ''}
-          ${optionalString (def.tunnelConfig != { }) ''
-            [Tunnel]
-            ${attrsToSection def.tunnelConfig}
-
-          ''}
-          ${optionalString (def.peerConfig != { }) ''
-            [Peer]
-            ${attrsToSection def.peerConfig}
-
-          ''}
-          ${optionalString (def.tunConfig != { }) ''
-            [Tun]
-            ${attrsToSection def.tunConfig}
-
-          ''}
-          ${optionalString (def.tapConfig != { }) ''
-            [Tap]
-            ${attrsToSection def.tapConfig}
-
-          ''}
-          ${optionalString (def.bondConfig != { }) ''
-            [Bond]
-            ${attrsToSection def.bondConfig}
-
-          ''}
-          ${optionalString (def.xfrmConfig != { }) ''
-            [Xfrm]
-            ${attrsToSection def.xfrmConfig}
-
-          ''}
-          ${optionalString (def.vrfConfig != { }) ''
-            [VRF]
-            ${attrsToSection def.vrfConfig}
-
-          ''}
-          ${optionalString (def.wireguardConfig != { }) ''
-            [WireGuard]
-            ${attrsToSection def.wireguardConfig}
-
-          ''}
-          ${flip concatMapStrings def.wireguardPeers (x: ''
-            [WireGuardPeer]
-            ${attrsToSection x.wireguardPeerConfig}
-
-          '')}
-          ${def.extraConfig}
-        '';
+        ''
+        + optionalString (def.vlanConfig != { }) ''
+          [VLAN]
+          ${attrsToSection def.vlanConfig}
+        ''
+        + optionalString (def.macvlanConfig != { }) ''
+          [MACVLAN]
+          ${attrsToSection def.macvlanConfig}
+        ''
+        + optionalString (def.vxlanConfig != { }) ''
+          [VXLAN]
+          ${attrsToSection def.vxlanConfig}
+        ''
+        + optionalString (def.tunnelConfig != { }) ''
+          [Tunnel]
+          ${attrsToSection def.tunnelConfig}
+        ''
+        + optionalString (def.peerConfig != { }) ''
+          [Peer]
+          ${attrsToSection def.peerConfig}
+        ''
+        + optionalString (def.tunConfig != { }) ''
+          [Tun]
+          ${attrsToSection def.tunConfig}
+        ''
+        + optionalString (def.tapConfig != { }) ''
+          [Tap]
+          ${attrsToSection def.tapConfig}
+        ''
+        + optionalString (def.wireguardConfig != { }) ''
+          [WireGuard]
+          ${attrsToSection def.wireguardConfig}
+        ''
+        + flip concatMapStrings def.wireguardPeers (x: ''
+          [WireGuardPeer]
+          ${attrsToSection x.wireguardPeerConfig}
+        '')
+        + optionalString (def.bondConfig != { }) ''
+          [Bond]
+          ${attrsToSection def.bondConfig}
+        ''
+        + optionalString (def.xfrmConfig != { }) ''
+          [Xfrm]
+          ${attrsToSection def.xfrmConfig}
+        ''
+        + optionalString (def.vrfConfig != { }) ''
+          [VRF]
+          ${attrsToSection def.vrfConfig}
+        ''
+        + def.extraConfig;
     };
 
   networkToUnit = name: def:
     { inherit (def) enable;
-      text = commonMatchText def +
+      text = commonMatchText def
+        + optionalString (def.linkConfig != { }) ''
+          [Link]
+          ${attrsToSection def.linkConfig}
         ''
-          ${optionalString (def.linkConfig != { }) ''
-            [Link]
-            ${attrsToSection def.linkConfig}
-
-          ''}
-
+        + ''
           [Network]
-          ${attrsToSection def.networkConfig}
+        ''
+        + attrsToSection def.networkConfig
+        + optionalString (def.address != [ ]) ''
           ${concatStringsSep "\n" (map (s: "Address=${s}") def.address)}
+        ''
+        + optionalString (def.gateway != [ ]) ''
           ${concatStringsSep "\n" (map (s: "Gateway=${s}") def.gateway)}
+        ''
+        + optionalString (def.dns != [ ]) ''
           ${concatStringsSep "\n" (map (s: "DNS=${s}") def.dns)}
+        ''
+        + optionalString (def.ntp != [ ]) ''
           ${concatStringsSep "\n" (map (s: "NTP=${s}") def.ntp)}
+        ''
+        + optionalString (def.bridge != [ ]) ''
           ${concatStringsSep "\n" (map (s: "Bridge=${s}") def.bridge)}
+        ''
+        + optionalString (def.bond != [ ]) ''
           ${concatStringsSep "\n" (map (s: "Bond=${s}") def.bond)}
+        ''
+        + optionalString (def.vrf != [ ]) ''
           ${concatStringsSep "\n" (map (s: "VRF=${s}") def.vrf)}
+        ''
+        + optionalString (def.vlan != [ ]) ''
           ${concatStringsSep "\n" (map (s: "VLAN=${s}") def.vlan)}
+        ''
+        + optionalString (def.macvlan != [ ]) ''
           ${concatStringsSep "\n" (map (s: "MACVLAN=${s}") def.macvlan)}
+        ''
+        + optionalString (def.vxlan != [ ]) ''
           ${concatStringsSep "\n" (map (s: "VXLAN=${s}") def.vxlan)}
+        ''
+        + optionalString (def.tunnel != [ ]) ''
           ${concatStringsSep "\n" (map (s: "Tunnel=${s}") def.tunnel)}
+        ''
+        + optionalString (def.xfrm != [ ]) ''
           ${concatStringsSep "\n" (map (s: "Xfrm=${s}") def.xfrm)}
+        ''
+        + ''
 
-          ${optionalString (def.dhcpV4Config != { }) ''
-            [DHCPv4]
-            ${attrsToSection def.dhcpV4Config}
-
-          ''}
-          ${optionalString (def.dhcpV6Config != {}) ''
-            [DHCPv6]
-            ${attrsToSection def.dhcpV6Config}
-
-          ''}
-          ${optionalString (def.ipv6PrefixDelegationConfig != {}) ''
-            [IPv6PrefixDelegation]
-            ${attrsToSection def.ipv6PrefixDelegationConfig}
-
-          ''}
-          ${flip concatMapStrings def.ipv6Prefixes (x: ''
-            [IPv6Prefix]
-            ${attrsToSection x.ipv6PrefixConfig}
-
-          '')}
-          ${optionalString (def.dhcpServerConfig != { }) ''
-            [DHCPServer]
-            ${attrsToSection def.dhcpServerConfig}
-
-          ''}
-          ${flip concatMapStrings def.addresses (x: ''
-            [Address]
-            ${attrsToSection x.addressConfig}
-
-          '')}
-          ${flip concatMapStrings def.routes (x: ''
-            [Route]
-            ${attrsToSection x.routeConfig}
-
-          '')}
-          ${flip concatMapStrings def.routingPolicyRules (x: ''
-            [RoutingPolicyRule]
-            ${attrsToSection x.routingPolicyRuleConfig}
-
-          '')}
-          ${def.extraConfig}
-        '';
+        ''
+        + flip concatMapStrings def.addresses (x: ''
+          [Address]
+          ${attrsToSection x.addressConfig}
+        '')
+        + flip concatMapStrings def.routingPolicyRules (x: ''
+          [RoutingPolicyRule]
+          ${attrsToSection x.routingPolicyRuleConfig}
+        '')
+        + flip concatMapStrings def.routes (x: ''
+          [Route]
+          ${attrsToSection x.routeConfig}
+        '')
+        + optionalString (def.dhcpV4Config != { }) ''
+          [DHCPv4]
+          ${attrsToSection def.dhcpV4Config}
+        ''
+        + optionalString (def.dhcpV6Config != { }) ''
+          [DHCPv6]
+          ${attrsToSection def.dhcpV6Config}
+        ''
+        + optionalString (def.dhcpServerConfig != { }) ''
+          [DHCPServer]
+          ${attrsToSection def.dhcpServerConfig}
+        ''
+        + optionalString (def.ipv6PrefixDelegationConfig != { }) ''
+          [IPv6PrefixDelegation]
+          ${attrsToSection def.ipv6PrefixDelegationConfig}
+        ''
+        + flip concatMapStrings def.ipv6Prefixes (x: ''
+          [IPv6Prefix]
+          ${attrsToSection x.ipv6PrefixConfig}
+        '')
+        + def.extraConfig;
     };
 
   unitFiles = listToAttrs (map (name: {
diff --git a/nixos/modules/system/boot/plymouth.nix b/nixos/modules/system/boot/plymouth.nix
index 23fce22366d8e..55e5b07ed615d 100644
--- a/nixos/modules/system/boot/plymouth.nix
+++ b/nixos/modules/system/boot/plymouth.nix
@@ -102,6 +102,8 @@ in
     systemd.services.plymouth-poweroff.wantedBy = [ "poweroff.target" ];
     systemd.services.plymouth-reboot.wantedBy = [ "reboot.target" ];
     systemd.services.plymouth-read-write.wantedBy = [ "sysinit.target" ];
+    systemd.services.systemd-ask-password-plymouth.wantedBy = ["multi-user.target"];
+    systemd.paths.systemd-ask-password-plymouth.wantedBy = ["multi-user.target"];
 
     boot.initrd.extraUtilsCommands = ''
       copy_bin_and_libs ${pkgs.plymouth}/bin/plymouthd
@@ -146,6 +148,7 @@ in
     # We use `mkAfter` to ensure that LUKS password prompt would be shown earlier than the splash screen.
     boot.initrd.preLVMCommands = mkAfter ''
       mkdir -p /etc/plymouth
+      mkdir -p /run/plymouth
       ln -s ${configFile} /etc/plymouth/plymouthd.conf
       ln -s $extraUtils/share/plymouth/plymouthd.defaults /etc/plymouth/plymouthd.defaults
       ln -s $extraUtils/share/plymouth/logo.png /etc/plymouth/logo.png
diff --git a/nixos/modules/system/boot/stage-1-init.sh b/nixos/modules/system/boot/stage-1-init.sh
index 607aec87f01e5..0c1be71cf5326 100644
--- a/nixos/modules/system/boot/stage-1-init.sh
+++ b/nixos/modules/system/boot/stage-1-init.sh
@@ -144,6 +144,14 @@ for o in $(cat /proc/cmdline); do
             set -- $(IFS==; echo $o)
             stage2Init=$2
             ;;
+        boot.persistence=*)
+            set -- $(IFS==; echo $o)
+            persistence=$2
+            ;;
+        boot.persistence.opt=*)
+            set -- $(IFS==; echo $o)
+            persistence_opt=$2
+            ;;
         boot.trace|debugtrace)
             # Show each command.
             set -x
@@ -370,12 +378,14 @@ mountFS() {
 
     mkdir -p "/mnt-root$mountPoint"
 
-    # For CIFS mounts, retry a few times before giving up.
+    # For ZFS and CIFS mounts, retry a few times before giving up.
+    # We do this for ZFS as a workaround for issue NixOS/nixpkgs#25383.
     local n=0
     while true; do
         mount "/mnt-root$mountPoint" && break
-        if [ "$fsType" != cifs -o "$n" -ge 10 ]; then fail; break; fi
+        if [ \( "$fsType" != cifs -a "$fsType" != zfs \) -o "$n" -ge 10 ]; then fail; break; fi
         echo "retrying..."
+        sleep 1
         n=$((n + 1))
     done
 
@@ -534,6 +544,14 @@ while read -u 3 mountPoint; do
       continue
     fi
 
+    if [ "$mountPoint" = / ] && [ "$device" = tmpfs ] && [ ! -z "$persistence" ]; then
+        echo persistence...
+        waitDevice "$persistence"
+        echo enabling persistence...
+        mountFS "$persistence" "$mountPoint" "$persistence_opt" "auto"
+        continue
+    fi
+
     mountFS "$device" "$mountPoint" "$options" "$fsType"
 done
 
diff --git a/nixos/modules/system/boot/stage-1.nix b/nixos/modules/system/boot/stage-1.nix
index d551466f52eb3..6823e12847c2f 100644
--- a/nixos/modules/system/boot/stage-1.nix
+++ b/nixos/modules/system/boot/stage-1.nix
@@ -36,7 +36,7 @@ let
     set -euo pipefail
 
     declare -A seen
-    declare -a left
+    left=()
 
     patchelf="${pkgs.buildPackages.patchelf}/bin/patchelf"
 
@@ -48,7 +48,7 @@ let
       done
     }
 
-    add_needed $1
+    add_needed "$1"
 
     while [ ''${#left[@]} -ne 0 ]; do
       next=''${left[0]}
@@ -111,20 +111,21 @@ let
       copy_bin_and_libs ${pkgs.utillinux}/sbin/blkid
 
       # Copy dmsetup and lvm.
-      copy_bin_and_libs ${pkgs.lvm2}/sbin/dmsetup
-      copy_bin_and_libs ${pkgs.lvm2}/sbin/lvm
+      copy_bin_and_libs ${getBin pkgs.lvm2}/bin/dmsetup
+      copy_bin_and_libs ${getBin pkgs.lvm2}/bin/lvm
 
       # Add RAID mdadm tool.
       copy_bin_and_libs ${pkgs.mdadm}/sbin/mdadm
       copy_bin_and_libs ${pkgs.mdadm}/sbin/mdmon
 
       # Copy udev.
-      copy_bin_and_libs ${udev}/lib/systemd/systemd-udevd
-      copy_bin_and_libs ${udev}/lib/systemd/systemd-sysctl
       copy_bin_and_libs ${udev}/bin/udevadm
+      copy_bin_and_libs ${udev}/lib/systemd/systemd-sysctl
       for BIN in ${udev}/lib/udev/*_id; do
         copy_bin_and_libs $BIN
       done
+      # systemd-udevd is only a symlink to udevadm these days
+      ln -sf udevadm $out/bin/systemd-udevd
 
       # Copy modprobe.
       copy_bin_and_libs ${pkgs.kmod}/bin/kmod
@@ -235,7 +236,7 @@ let
             --replace cdrom_id ${extraUtils}/bin/cdrom_id \
             --replace ${pkgs.coreutils}/bin/basename ${extraUtils}/bin/basename \
             --replace ${pkgs.utillinux}/bin/blkid ${extraUtils}/bin/blkid \
-            --replace ${pkgs.lvm2}/sbin ${extraUtils}/bin \
+            --replace ${getBin pkgs.lvm2}/bin ${extraUtils}/bin \
             --replace ${pkgs.mdadm}/sbin ${extraUtils}/sbin \
             --replace ${pkgs.bash}/bin/sh ${extraUtils}/bin/sh \
             --replace ${udev} ${extraUtils}
@@ -374,7 +375,8 @@ let
           ) config.boot.initrd.secrets)
          }
 
-        (cd "$tmp" && find . | cpio -H newc -o) | gzip >>"$1"
+        (cd "$tmp" && find . -print0 | sort -z | cpio -o -H newc -R +0:+0 --reproducible --null) | \
+          ${config.boot.initrd.compressor} >> "$1"
       '';
 
 in
@@ -554,15 +556,17 @@ in
       };
 
     fileSystems = mkOption {
-      type = with lib.types; loaOf (submodule {
+      type = with lib.types; attrsOf (submodule {
         options.neededForBoot = mkOption {
           default = false;
           type = types.bool;
           description = ''
-            If set, this file system will be mounted in the initial
-            ramdisk.  By default, this applies to the root file system
-            and to the file system containing
-            <filename>/nix/store</filename>.
+            If set, this file system will be mounted in the initial ramdisk.
+            Note that the file system will always be mounted in the initial
+            ramdisk if its mount point is one of the following:
+            ${concatStringsSep ", " (
+              forEach utils.pathsNeededForBoot (i: "<filename>${i}</filename>")
+            )}.
           '';
         };
       });
diff --git a/nixos/modules/system/boot/stage-2-init.sh b/nixos/modules/system/boot/stage-2-init.sh
index d1de7920df987..936077b9df1eb 100644
--- a/nixos/modules/system/boot/stage-2-init.sh
+++ b/nixos/modules/system/boot/stage-2-init.sh
@@ -169,4 +169,4 @@ exec {logOutFd}>&- {logErrFd}>&-
 echo "starting systemd..."
 PATH=/run/current-system/systemd/lib/systemd:@fsPackagesPath@ \
     LOCALE_ARCHIVE=/run/current-system/sw/lib/locale/locale-archive \
-    exec systemd
+    exec @systemdExecutable@
diff --git a/nixos/modules/system/boot/stage-2.nix b/nixos/modules/system/boot/stage-2.nix
index 6b0b472273017..dd6d83ee00947 100644
--- a/nixos/modules/system/boot/stage-2.nix
+++ b/nixos/modules/system/boot/stage-2.nix
@@ -10,6 +10,7 @@ let
     src = ./stage-2-init.sh;
     shellDebug = "${pkgs.bashInteractive}/bin/bash";
     shell = "${pkgs.bash}/bin/bash";
+    inherit (config.boot) systemdExecutable;
     isExecutable = true;
     inherit (config.nix) readOnlyStore;
     inherit useHostResolvConf;
@@ -72,6 +73,15 @@ in
         '';
       };
 
+      systemdExecutable = mkOption {
+        default = "systemd";
+        type = types.str;
+        description = ''
+          The program to execute to start systemd. Typically
+          <literal>systemd</literal>, which will find systemd in the
+          PATH.
+        '';
+      };
     };
 
   };
diff --git a/nixos/modules/system/boot/systemd-nspawn.nix b/nixos/modules/system/boot/systemd-nspawn.nix
index 06ea5ee49f727..b450d77429b21 100644
--- a/nixos/modules/system/boot/systemd-nspawn.nix
+++ b/nixos/modules/system/boot/systemd-nspawn.nix
@@ -113,9 +113,9 @@ in {
   config =
     let
       units = mapAttrs' (n: v: let nspawnFile = "${n}.nspawn"; in nameValuePair nspawnFile (instanceToUnit nspawnFile v)) cfg;
-    in 
+    in
       mkMerge [
-        (mkIf (cfg != {}) { 
+        (mkIf (cfg != {}) {
           environment.etc."systemd/nspawn".source = mkIf (cfg != {}) (generateUnits' false "nspawn" units [] []);
         })
         {
@@ -123,7 +123,7 @@ in {
 
           # Workaround for https://github.com/NixOS/nixpkgs/pull/67232#issuecomment-531315437 and https://github.com/systemd/systemd/issues/13622
           # Once systemd fixes this upstream, we can re-enable -U
-          systemd.services."systemd-nspawn@".serviceConfig.ExecStart = [ 
+          systemd.services."systemd-nspawn@".serviceConfig.ExecStart = [
             ""  # deliberately empty. signals systemd to override the ExecStart
             # Only difference between upstream is that we do not pass the -U flag
             "${config.systemd.package}/bin/systemd-nspawn --quiet --keep-unit --boot --link-journal=try-guest --network-veth --settings=override --machine=%i"
diff --git a/nixos/modules/system/boot/systemd-unit-options.nix b/nixos/modules/system/boot/systemd-unit-options.nix
index c6dbb96951ae0..5addc6f9ca44d 100644
--- a/nixos/modules/system/boot/systemd-unit-options.nix
+++ b/nixos/modules/system/boot/systemd-unit-options.nix
@@ -234,7 +234,6 @@ in rec {
     path = mkOption {
       default = [];
       type = with types; listOf (oneOf [ package str ]);
-      apply = ps: "${makeBinPath ps}:${makeSearchPathOutput "bin" "sbin" ps}";
       description = ''
         Packages added to the service's <envar>PATH</envar>
         environment variable.  Both the <filename>bin</filename>
@@ -379,6 +378,16 @@ in rec {
       '';
     };
 
+    listenDatagrams = mkOption {
+      default = [];
+      type = types.listOf types.str;
+      example = [ "0.0.0.0:993" "/run/my-socket" ];
+      description = ''
+        For each item in this list, a <literal>ListenDatagram</literal>
+        option in the <literal>[Socket]</literal> section will be created.
+      '';
+    };
+
     socketConfig = mkOption {
       default = {};
       example = { ListenStream = "/run/my-socket"; };
diff --git a/nixos/modules/system/boot/systemd.nix b/nixos/modules/system/boot/systemd.nix
index a8e51fc09014d..74d6957678f56 100644
--- a/nixos/modules/system/boot/systemd.nix
+++ b/nixos/modules/system/boot/systemd.nix
@@ -25,7 +25,7 @@ let
       "nss-lookup.target"
       "nss-user-lookup.target"
       "time-sync.target"
-      #"cryptsetup.target"
+      "cryptsetup.target"
       "sigpwr.target"
       "timers.target"
       "paths.target"
@@ -73,7 +73,7 @@ let
       "systemd-journald.service"
       "systemd-journal-flush.service"
       "systemd-journal-catalog-update.service"
-      "systemd-journald-audit.socket"
+      ] ++ (optional (!config.boot.isContainer) "systemd-journald-audit.socket") ++ [
       "systemd-journald-dev-log.socket"
       "syslog.socket"
 
@@ -81,10 +81,6 @@ let
       "systemd-coredump.socket"
       "systemd-coredump@.service"
 
-      # SysV init compatibility.
-      "systemd-initctl.socket"
-      "systemd-initctl.service"
-
       # Kernel module loading.
       "systemd-modules-load.service"
       "kmod-static-nodes.service"
@@ -101,7 +97,7 @@ let
       "dev-hugepages.mount"
       "dev-mqueue.mount"
       "sys-fs-fuse-connections.mount"
-      "sys-kernel-config.mount"
+      ] ++ (optional (!config.boot.isContainer) "sys-kernel-config.mount") ++ [
       "sys-kernel-debug.mount"
 
       # Maintaining state across reboots.
@@ -261,7 +257,7 @@ let
               pkgs.gnused
               systemd
             ];
-          environment.PATH = config.path;
+          environment.PATH = "${makeBinPath config.path}:${makeSearchPathOutput "bin" "sbin" config.path}";
         }
         (mkIf (config.preStart != "")
           { serviceConfig.ExecStartPre =
@@ -354,6 +350,7 @@ let
           [Socket]
           ${attrsToSection def.socketConfig}
           ${concatStringsSep "\n" (map (s: "ListenStream=${s}") def.listenStreams)}
+          ${concatStringsSep "\n" (map (s: "ListenDatagram=${s}") def.listenDatagrams)}
         '';
     };
 
@@ -749,6 +746,25 @@ in
       '';
     };
 
+    systemd.tmpfiles.packages = mkOption {
+      type = types.listOf types.package;
+      default = [];
+      example = literalExample "[ pkgs.lvm2 ]";
+      apply = map getLib;
+      description = ''
+        List of packages containing <command>systemd-tmpfiles</command> rules.
+
+        All files ending in .conf found in
+        <filename><replaceable>pkg</replaceable>/lib/tmpfiles.d</filename>
+        will be included.
+        If this folder does not exist or does not contain any files an error will be returned instead.
+
+        If a <filename>lib</filename> output is available, rules are searched there and only there.
+        If there is no <filename>lib</filename> output it will fall back to <filename>out</filename>
+        and if that does not exist either, the default output will be used.
+      '';
+    };
+
     systemd.user.units = mkOption {
       description = "Definition of systemd per-user units.";
       default = {};
@@ -818,6 +834,49 @@ in
       '';
     };
 
+    systemd.watchdog.device = mkOption {
+      type = types.nullOr types.path;
+      default = null;
+      example = "/dev/watchdog";
+      description = ''
+        The path to a hardware watchdog device which will be managed by systemd.
+        If not specified, systemd will default to /dev/watchdog.
+      '';
+    };
+
+    systemd.watchdog.runtimeTime = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      example = "30s";
+      description = ''
+        The amount of time which can elapse before a watchdog hardware device
+        will automatically reboot the system. Valid time units include "ms",
+        "s", "min", "h", "d", and "w".
+      '';
+    };
+
+    systemd.watchdog.rebootTime = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      example = "10m";
+      description = ''
+        The amount of time which can elapse after a reboot has been triggered
+        before a watchdog hardware device will automatically reboot the system.
+        Valid time units include "ms", "s", "min", "h", "d", and "w".
+      '';
+    };
+
+    systemd.watchdog.kexecTime = mkOption {
+      type = types.nullOr types.str;
+      default = null;
+      example = "10m";
+      description = ''
+        The amount of time which can elapse when kexec is being executed before
+        a watchdog hardware device will automatically reboot the system. This
+        option should only be enabled if reloadTime is also enabled. Valid
+        time units include "ms", "s", "min", "h", "d", and "w".
+      '';
+    };
   };
 
 
@@ -844,11 +903,9 @@ in
       )
       ]);
       passwd = (mkMerge [
-        [ "mymachines" ]
         (mkAfter [ "systemd" ])
       ]);
       group = (mkMerge [
-        [ "mymachines" ]
         (mkAfter [ "systemd" ])
       ]);
     };
@@ -889,6 +946,19 @@ in
           DefaultIPAccounting=yes
         ''}
         DefaultLimitCORE=infinity
+        ${optionalString (config.systemd.watchdog.device != null) ''
+          WatchdogDevice=${config.systemd.watchdog.device}
+        ''}
+        ${optionalString (config.systemd.watchdog.runtimeTime != null) ''
+          RuntimeWatchdogSec=${config.systemd.watchdog.runtimeTime}
+        ''}
+        ${optionalString (config.systemd.watchdog.rebootTime != null) ''
+          RebootWatchdogSec=${config.systemd.watchdog.rebootTime}
+        ''}
+        ${optionalString (config.systemd.watchdog.kexecTime != null) ''
+          KExecWatchdogSec=${config.systemd.watchdog.kexecTime}
+        ''}
+
         ${config.systemd.extraConfig}
       '';
 
@@ -936,24 +1006,20 @@ in
       "sysctl.d/50-coredump.conf".source = "${systemd}/example/sysctl.d/50-coredump.conf";
       "sysctl.d/50-default.conf".source = "${systemd}/example/sysctl.d/50-default.conf";
 
-      "tmpfiles.d/00-nixos.conf".text = ''
-        # This file is created automatically and should not be modified.
-        # Please change the option ‘systemd.tmpfiles.rules’ instead.
-
-        ${concatStringsSep "\n" cfg.tmpfiles.rules}
-      '';
-
-      "tmpfiles.d/home.conf".source = "${systemd}/example/tmpfiles.d/home.conf";
-      "tmpfiles.d/journal-nocow.conf".source = "${systemd}/example/tmpfiles.d/journal-nocow.conf";
-      "tmpfiles.d/portables.conf".source = "${systemd}/example/tmpfiles.d/portables.conf";
-      "tmpfiles.d/static-nodes-permissions.conf".source = "${systemd}/example/tmpfiles.d/static-nodes-permissions.conf";
-      "tmpfiles.d/systemd.conf".source = "${systemd}/example/tmpfiles.d/systemd.conf";
-      "tmpfiles.d/systemd-nologin.conf".source = "${systemd}/example/tmpfiles.d/systemd-nologin.conf";
-      "tmpfiles.d/systemd-nspawn.conf".source = "${systemd}/example/tmpfiles.d/systemd-nspawn.conf";
-      "tmpfiles.d/systemd-tmp.conf".source = "${systemd}/example/tmpfiles.d/systemd-tmp.conf";
-      "tmpfiles.d/tmp.conf".source = "${systemd}/example/tmpfiles.d/tmp.conf";
-      "tmpfiles.d/var.conf".source = "${systemd}/example/tmpfiles.d/var.conf";
-      "tmpfiles.d/x11.conf".source = "${systemd}/example/tmpfiles.d/x11.conf";
+      "tmpfiles.d".source = (pkgs.symlinkJoin {
+        name = "tmpfiles.d";
+        paths = map (p: p + "/lib/tmpfiles.d") cfg.tmpfiles.packages;
+        postBuild = ''
+          for i in $(cat $pathsPath); do
+            (test -d "$i" && test $(ls "$i"/*.conf | wc -l) -ge 1) || (
+              echo "ERROR: The path '$i' from systemd.tmpfiles.packages contains no *.conf files."
+              exit 1
+            )
+          done
+        '' + concatMapStrings (name: optionalString (hasPrefix "tmpfiles.d/" name) ''
+          rm -f $out/${removePrefix "tmpfiles.d/" name}
+        '') config.system.build.etc.targets;
+      }) + "/*";
 
       "systemd/system-generators" = { source = hooks "generators" cfg.generators; };
       "systemd/system-shutdown" = { source = hooks "shutdown" cfg.shutdown; };
@@ -974,6 +1040,36 @@ in
         unitConfig.X-StopOnReconfiguration = true;
       };
 
+    systemd.tmpfiles.packages = [
+      # Default tmpfiles rules provided by systemd
+      (pkgs.runCommand "systemd-default-tmpfiles" {} ''
+        mkdir -p $out/lib/tmpfiles.d
+        cd $out/lib/tmpfiles.d
+
+        ln -s "${systemd}/example/tmpfiles.d/home.conf"
+        ln -s "${systemd}/example/tmpfiles.d/journal-nocow.conf"
+        ln -s "${systemd}/example/tmpfiles.d/static-nodes-permissions.conf"
+        ln -s "${systemd}/example/tmpfiles.d/systemd.conf"
+        ln -s "${systemd}/example/tmpfiles.d/systemd-nologin.conf"
+        ln -s "${systemd}/example/tmpfiles.d/systemd-nspawn.conf"
+        ln -s "${systemd}/example/tmpfiles.d/systemd-tmp.conf"
+        ln -s "${systemd}/example/tmpfiles.d/tmp.conf"
+        ln -s "${systemd}/example/tmpfiles.d/var.conf"
+        ln -s "${systemd}/example/tmpfiles.d/x11.conf"
+      '')
+      # User-specified tmpfiles rules
+      (pkgs.writeTextFile {
+        name = "nixos-tmpfiles.d";
+        destination = "/lib/tmpfiles.d/00-nixos.conf";
+        text = ''
+          # This file is created automatically and should not be modified.
+          # Please change the option ‘systemd.tmpfiles.rules’ instead.
+
+          ${concatStringsSep "\n" cfg.tmpfiles.rules}
+        '';
+      })
+    ];
+
     systemd.units =
          mapAttrs' (n: v: nameValuePair "${n}.path"    (pathToUnit    n v)) cfg.paths
       // mapAttrs' (n: v: nameValuePair "${n}.service" (serviceToUnit n v)) cfg.services
diff --git a/nixos/modules/system/boot/tmp.nix b/nixos/modules/system/boot/tmp.nix
index 5bf5e2eb2ec58..26eb172210e73 100644
--- a/nixos/modules/system/boot/tmp.nix
+++ b/nixos/modules/system/boot/tmp.nix
@@ -36,4 +36,4 @@ with lib;
 
   };
 
-}
\ No newline at end of file
+}
diff --git a/nixos/modules/system/etc/etc.nix b/nixos/modules/system/etc/etc.nix
index 1f4d54a1ae205..7478e3e80717f 100644
--- a/nixos/modules/system/etc/etc.nix
+++ b/nixos/modules/system/etc/etc.nix
@@ -46,7 +46,7 @@ in
         Set of files that have to be linked in <filename>/etc</filename>.
       '';
 
-      type = with types; loaOf (submodule (
+      type = with types; attrsOf (submodule (
         { name, config, ... }:
         { options = {
 
diff --git a/nixos/modules/system/etc/make-etc.sh b/nixos/modules/system/etc/make-etc.sh
index 1ca4c3046f0e5..aabfb5e88a655 100644
--- a/nixos/modules/system/etc/make-etc.sh
+++ b/nixos/modules/system/etc/make-etc.sh
@@ -23,7 +23,7 @@ for ((i = 0; i < ${#targets_[@]}; i++)); do
         done
 
     else
-        
+
         mkdir -p $out/etc/$(dirname $target)
         if ! [ -e $out/etc/$target ]; then
             ln -s $source $out/etc/$target
@@ -34,13 +34,12 @@ for ((i = 0; i < ${#targets_[@]}; i++)); do
                 exit 1
             fi
         fi
-        
+
         if test "${modes_[$i]}" != symlink; then
             echo "${modes_[$i]}"  > $out/etc/$target.mode
             echo "${users_[$i]}"  > $out/etc/$target.uid
             echo "${groups_[$i]}" > $out/etc/$target.gid
         fi
-        
+
     fi
 done
-
diff --git a/nixos/modules/tasks/auto-upgrade.nix b/nixos/modules/tasks/auto-upgrade.nix
index e70004e643e10..69385e5f2fe01 100644
--- a/nixos/modules/tasks/auto-upgrade.nix
+++ b/nixos/modules/tasks/auto-upgrade.nix
@@ -2,9 +2,9 @@
 
 with lib;
 
-let cfg = config.system.autoUpgrade; in
+let cfg = config.system.autoUpgrade;
 
-{
+in {
 
   options = {
 
@@ -21,6 +21,16 @@ let cfg = config.system.autoUpgrade; in
         '';
       };
 
+      flake = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        example = "github:kloenk/nix";
+        description = ''
+          The Flake URI of the NixOS configuration to build.
+          Disables the option <option>system.autoUpgrade.channel</option>.
+        '';
+      };
+
       channel = mkOption {
         type = types.nullOr types.str;
         default = null;
@@ -35,10 +45,20 @@ let cfg = config.system.autoUpgrade; in
 
       flags = mkOption {
         type = types.listOf types.str;
-        default = [];
-        example = [ "-I" "stuff=/home/alice/nixos-stuff" "--option" "extra-binary-caches" "http://my-cache.example.org/" ];
+        default = [ ];
+        example = [
+          "-I"
+          "stuff=/home/alice/nixos-stuff"
+          "--option"
+          "extra-binary-caches"
+          "http://my-cache.example.org/"
+        ];
         description = ''
           Any additional flags passed to <command>nixos-rebuild</command>.
+
+          If you are using flakes and use a local repo you can add
+          <command>[ "--update-input" "nixpkgs" "--commit-lock-file" ]</command>
+          to update nixpkgs.
         '';
       };
 
@@ -82,11 +102,23 @@ let cfg = config.system.autoUpgrade; in
 
   config = lib.mkIf cfg.enable {
 
-    system.autoUpgrade.flags =
-      [ "--no-build-output" ]
-      ++ (if cfg.channel == null
-          then [ "--upgrade" ]
-          else [ "-I" "nixpkgs=${cfg.channel}/nixexprs.tar.xz" ]);
+    assertions = [{
+      assertion = !((cfg.channel != null) && (cfg.flake != null));
+      message = ''
+        The options 'system.autoUpgrade.channels' and 'system.autoUpgrade.flake' cannot both be set.
+      '';
+    }];
+
+    system.autoUpgrade.flags = [ "--no-build-output" ]
+      ++ (if cfg.flake == null then
+        (if cfg.channel == null then
+          [ "--upgrade" ]
+        else [
+          "-I"
+          "nixpkgs=${cfg.channel}/nixexprs.tar.xz"
+        ])
+      else
+        [ "--flake ${cfg.flake}" ]);
 
     systemd.services.nixos-upgrade = {
       description = "NixOS Upgrade";
@@ -96,33 +128,41 @@ let cfg = config.system.autoUpgrade; in
 
       serviceConfig.Type = "oneshot";
 
-      environment = config.nix.envVars //
-        { inherit (config.environment.sessionVariables) NIX_PATH;
-          HOME = "/root";
-        } // config.networking.proxy.envVars;
+      environment = config.nix.envVars // {
+        inherit (config.environment.sessionVariables) NIX_PATH;
+        HOME = "/root";
+      } // config.networking.proxy.envVars;
 
-      path = with pkgs; [ coreutils gnutar xz.bin gzip gitMinimal config.nix.package.out ];
+      path = with pkgs; [
+        coreutils
+        gnutar
+        xz.bin
+        gzip
+        gitMinimal
+        config.nix.package.out
+      ];
 
       script = let
-          nixos-rebuild = "${config.system.build.nixos-rebuild}/bin/nixos-rebuild";
-        in
-        if cfg.allowReboot then ''
-            ${nixos-rebuild} boot ${toString cfg.flags}
-            booted="$(readlink /run/booted-system/{initrd,kernel,kernel-modules})"
-            built="$(readlink /nix/var/nix/profiles/system/{initrd,kernel,kernel-modules})"
-            if [ "$booted" = "$built" ]; then
-              ${nixos-rebuild} switch ${toString cfg.flags}
-            else
-              /run/current-system/sw/bin/shutdown -r +1
-            fi
-          '' else ''
-            ${nixos-rebuild} switch ${toString cfg.flags}
-        '';
+        nixos-rebuild =
+          "${config.system.build.nixos-rebuild}/bin/nixos-rebuild";
+      in if cfg.allowReboot then ''
+        ${nixos-rebuild} boot ${toString cfg.flags}
+        booted="$(readlink /run/booted-system/{initrd,kernel,kernel-modules})"
+        built="$(readlink /nix/var/nix/profiles/system/{initrd,kernel,kernel-modules})"
+        if [ "$booted" = "$built" ]; then
+          ${nixos-rebuild} switch ${toString cfg.flags}
+        else
+          /run/current-system/sw/bin/shutdown -r +1
+        fi
+      '' else ''
+        ${nixos-rebuild} switch ${toString cfg.flags}
+      '';
 
       startAt = cfg.dates;
     };
 
-    systemd.timers.nixos-upgrade.timerConfig.RandomizedDelaySec = cfg.randomizedDelaySec;
+    systemd.timers.nixos-upgrade.timerConfig.RandomizedDelaySec =
+      cfg.randomizedDelaySec;
 
   };
 
diff --git a/nixos/modules/tasks/bcache.nix b/nixos/modules/tasks/bcache.nix
index 8bab91c721fdc..41fb7664f3d17 100644
--- a/nixos/modules/tasks/bcache.nix
+++ b/nixos/modules/tasks/bcache.nix
@@ -8,6 +8,6 @@
 
   boot.initrd.extraUdevRulesCommands = ''
     cp -v ${pkgs.bcache-tools}/lib/udev/rules.d/*.rules $out/
-  ''; 
+  '';
 
 }
diff --git a/nixos/modules/tasks/encrypted-devices.nix b/nixos/modules/tasks/encrypted-devices.nix
index bc0933f16fec4..dd337de98698c 100644
--- a/nixos/modules/tasks/encrypted-devices.nix
+++ b/nixos/modules/tasks/encrypted-devices.nix
@@ -37,7 +37,14 @@ let
         default = null;
         example = "/mnt-root/root/.swapkey";
         type = types.nullOr types.str;
-        description = "File system location of keyfile. This unlocks the drive after the root has been mounted to <literal>/mnt-root</literal>.";
+        description = ''
+          Path to a keyfile used to unlock the backing encrypted
+          device. At the time this keyfile is accessed, the
+          <literal>neededForBoot</literal> filesystems (see
+          <literal>fileSystems.&lt;name?&gt;.neededForBoot</literal>)
+          will have been mounted under <literal>/mnt-root</literal>,
+          so the keyfile path should usually start with "/mnt-root/".
+        '';
       };
     };
   };
@@ -47,7 +54,7 @@ in
 
   options = {
     fileSystems = mkOption {
-      type = with lib.types; loaOf (submodule encryptedFSOptions);
+      type = with lib.types; attrsOf (submodule encryptedFSOptions);
     };
     swapDevices = mkOption {
       type = with lib.types; listOf (submodule encryptedFSOptions);
@@ -65,12 +72,16 @@ in
     boot.initrd = {
       luks = {
         devices =
-          builtins.listToAttrs (map (dev: { name = dev.encrypted.label; value = { device = dev.encrypted.blkDev; }; }) keylessEncDevs);
+          builtins.listToAttrs (map (dev: {
+            name = dev.encrypted.label;
+            value = { device = dev.encrypted.blkDev; };
+          }) keylessEncDevs);
         forceLuksSupportInInitrd = true;
       };
       postMountCommands =
-        concatMapStrings (dev: "cryptsetup luksOpen --key-file ${dev.encrypted.keyFile} ${dev.encrypted.blkDev} ${dev.encrypted.label};\n") keyedEncDevs;
+        concatMapStrings (dev:
+          "cryptsetup luksOpen --key-file ${dev.encrypted.keyFile} ${dev.encrypted.blkDev} ${dev.encrypted.label};\n"
+        ) keyedEncDevs;
     };
   };
 }
-
diff --git a/nixos/modules/tasks/filesystems.nix b/nixos/modules/tasks/filesystems.nix
index 0ade74b957a0c..3ea67dac7146d 100644
--- a/nixos/modules/tasks/filesystems.nix
+++ b/nixos/modules/tasks/filesystems.nix
@@ -159,7 +159,7 @@ in
           "/bigdisk".label = "bigdisk";
         }
       '';
-      type = types.loaOf (types.submodule [coreFileSystemOpts fileSystemOpts]);
+      type = types.attrsOf (types.submodule [coreFileSystemOpts fileSystemOpts]);
       description = ''
         The file systems to be mounted.  It must include an entry for
         the root directory (<literal>mountPoint = "/"</literal>).  Each
@@ -193,7 +193,7 @@ in
 
     boot.specialFileSystems = mkOption {
       default = {};
-      type = types.loaOf (types.submodule coreFileSystemOpts);
+      type = types.attrsOf (types.submodule coreFileSystemOpts);
       internal = true;
       description = ''
         Special filesystems that are mounted very early during boot.
diff --git a/nixos/modules/tasks/filesystems/zfs.nix b/nixos/modules/tasks/filesystems/zfs.nix
index 71eed4d6f1a40..9ca7c6fb3431b 100644
--- a/nixos/modules/tasks/filesystems/zfs.nix
+++ b/nixos/modules/tasks/filesystems/zfs.nix
@@ -191,15 +191,14 @@ in
       };
 
       requestEncryptionCredentials = mkOption {
-        type = types.bool;
+        type = types.either types.bool (types.listOf types.str);
         default = true;
+        example = [ "tank" "data" ];
         description = ''
-          Request encryption keys or passwords for all encrypted datasets on import.
-          For root pools the encryption key can be supplied via both an
-          interactive prompt (keylocation=prompt) and from a file
-          (keylocation=file://). Note that for data pools the encryption key can
-          be only loaded from a file and not via interactive prompt since the
-          import is processed in a background systemd service.
+          If true on import encryption keys or passwords for all encrypted datasets
+          are requested. To only decrypt selected datasets supply a list of dataset
+          names instead. For root pools the encryption key can be supplied via both
+          an interactive prompt (keylocation=prompt) and from a file (keylocation=file://).
         '';
       };
 
@@ -421,9 +420,13 @@ in
               fi
               poolImported "${pool}" || poolImport "${pool}"  # Try one last time, e.g. to import a degraded pool.
             fi
-            ${lib.optionalString cfgZfs.requestEncryptionCredentials ''
-              zfs load-key -a
-            ''}
+            ${if isBool cfgZfs.requestEncryptionCredentials
+              then optionalString cfgZfs.requestEncryptionCredentials ''
+                zfs load-key -a
+              ''
+              else concatMapStrings (fs: ''
+                zfs load-key ${fs}
+              '') cfgZfs.requestEncryptionCredentials}
         '') rootPools));
       };
 
@@ -490,7 +493,11 @@ in
             description = "Import ZFS pool \"${pool}\"";
             # we need systemd-udev-settle until https://github.com/zfsonlinux/zfs/pull/4943 is merged
             requires = [ "systemd-udev-settle.service" ];
-            after = [ "systemd-udev-settle.service" "systemd-modules-load.service" ];
+            after = [
+              "systemd-udev-settle.service"
+              "systemd-modules-load.service"
+              "systemd-ask-password-console.service"
+            ];
             wantedBy = (getPoolMounts pool) ++ [ "local-fs.target" ];
             before = (getPoolMounts pool) ++ [ "local-fs.target" ];
             unitConfig = {
@@ -515,7 +522,27 @@ in
               done
               poolImported "${pool}" || poolImport "${pool}"  # Try one last time, e.g. to import a degraded pool.
               if poolImported "${pool}"; then
-                ${optionalString cfgZfs.requestEncryptionCredentials "\"${packages.zfsUser}/sbin/zfs\" load-key -r \"${pool}\""}
+                ${optionalString (if isBool cfgZfs.requestEncryptionCredentials
+                                  then cfgZfs.requestEncryptionCredentials
+                                  else cfgZfs.requestEncryptionCredentials != []) ''
+                  ${packages.zfsUser}/sbin/zfs list -rHo name,keylocation ${pool} | while IFS=$'\t' read ds kl; do
+                    (${optionalString (!isBool cfgZfs.requestEncryptionCredentials) ''
+                         if ! echo '${concatStringsSep "\n" cfgZfs.requestEncryptionCredentials}' | grep -qFx "$ds"; then
+                           continue
+                         fi
+                       ''}
+                    case "$kl" in
+                      none )
+                        ;;
+                      prompt )
+                        ${config.systemd.package}/bin/systemd-ask-password "Enter key for $ds:" | ${packages.zfsUser}/sbin/zfs load-key "$ds"
+                        ;;
+                      * )
+                        ${packages.zfsUser}/sbin/zfs load-key "$ds"
+                        ;;
+                    esac) < /dev/null # To protect while read ds kl in case anything reads stdin
+                  done
+                ''}
                 echo "Successfully imported ${pool}"
               else
                 exit 1
diff --git a/nixos/modules/tasks/lvm.nix b/nixos/modules/tasks/lvm.nix
index d56a8a2f63a8d..2c3cc4c5467dc 100644
--- a/nixos/modules/tasks/lvm.nix
+++ b/nixos/modules/tasks/lvm.nix
@@ -1,17 +1,70 @@
 { config, lib, pkgs, ... }:
 
 with lib;
+let
+  cfg = config.services.lvm;
+in {
+  options.services.lvm = {
+    package = mkOption {
+      type = types.package;
+      default = if cfg.dmeventd.enable then pkgs.lvm2_dmeventd else pkgs.lvm2;
+      internal = true;
+      defaultText = "pkgs.lvm2";
+      description = ''
+        This option allows you to override the LVM package that's used on the system
+        (udev rules, tmpfiles, systemd services).
+        Defaults to pkgs.lvm2, or pkgs.lvm2_dmeventd if dmeventd is enabled.
+      '';
+    };
+    dmeventd.enable = mkEnableOption "the LVM dmevent daemon";
+    boot.thin.enable = mkEnableOption "support for booting from ThinLVs";
+  };
 
-{
-
-  ###### implementation
+  config = mkMerge [
+    (mkIf (!config.boot.isContainer) {
+      systemd.tmpfiles.packages = [ cfg.package.out ];
+      environment.systemPackages = [ cfg.package ];
+      systemd.packages = [ cfg.package ];
 
-  config = mkIf (!config.boot.isContainer) {
+      # TODO: update once https://github.com/NixOS/nixpkgs/pull/93006 was merged
+      services.udev.packages = [ cfg.package.out ];
+    })
+    (mkIf cfg.dmeventd.enable {
+      systemd.sockets."dm-event".wantedBy = [ "sockets.target" ];
+      systemd.services."lvm2-monitor".wantedBy = [ "sysinit.target" ];
 
-    environment.systemPackages = [ pkgs.lvm2 ];
+      environment.etc."lvm/lvm.conf".text = ''
+        dmeventd/executable = "${cfg.package}/bin/dmeventd"
+      '';
+    })
+    (mkIf cfg.boot.thin.enable {
+      boot.initrd = {
+        kernelModules = [ "dm-snapshot" "dm-thin-pool" ];
 
-    services.udev.packages = [ pkgs.lvm2 ];
+        extraUtilsCommands = ''
+          copy_bin_and_libs ${pkgs.thin-provisioning-tools}/bin/pdata_tools
+          copy_bin_and_libs ${pkgs.thin-provisioning-tools}/bin/thin_check
+        '';
+      };
 
-  };
+      environment.etc."lvm/lvm.conf".text = ''
+        global/thin_check_executable = "${pkgs.thin-provisioning-tools}/bin/thin_check"
+      '';
+    })
+    (mkIf (cfg.dmeventd.enable || cfg.boot.thin.enable) {
+      boot.initrd.preLVMCommands = ''
+          mkdir -p /etc/lvm
+          cat << EOF >> /etc/lvm/lvm.conf
+          ${optionalString cfg.boot.thin.enable ''
+            global/thin_check_executable = "$(command -v thin_check)"
+          ''}
+          ${optionalString cfg.dmeventd.enable ''
+            dmeventd/executable = "$(command -v false)"
+            activation/monitoring = 0
+          ''}
+          EOF
+      '';
+    })
+  ];
 
 }
diff --git a/nixos/modules/tasks/network-interfaces-scripted.nix b/nixos/modules/tasks/network-interfaces-scripted.nix
index 2e87197176b68..9ba6ccfbe7167 100644
--- a/nixos/modules/tasks/network-interfaces-scripted.nix
+++ b/nixos/modules/tasks/network-interfaces-scripted.nix
@@ -253,8 +253,8 @@ let
 
         createTunDevice = i: nameValuePair "${i.name}-netdev"
           { description = "Virtual Network Interface ${i.name}";
-            bindsTo = [ "dev-net-tun.device" ];
-            after = [ "dev-net-tun.device" "network-pre.target" ];
+            bindsTo = optional (!config.boot.isContainer) "dev-net-tun.device";
+            after = optional (!config.boot.isContainer) "dev-net-tun.device" ++ [ "network-pre.target" ];
             wantedBy = [ "network-setup.service" (subsystemDevice i.name) ];
             partOf = [ "network-setup.service" ];
             before = [ "network-setup.service" ];
diff --git a/nixos/modules/tasks/network-interfaces.nix b/nixos/modules/tasks/network-interfaces.nix
index 78d6696694997..c0e4d3979fdad 100644
--- a/nixos/modules/tasks/network-interfaces.nix
+++ b/nixos/modules/tasks/network-interfaces.nix
@@ -408,6 +408,9 @@ in
         (this derives it from the machine-id that systemd generates) or
 
         <literal>head -c4 /dev/urandom | od -A none -t x4</literal>
+
+        The primary use case is to ensure when using ZFS that a pool isn't imported
+        accidentally on a wrong machine.
       '';
     };
 
@@ -516,7 +519,7 @@ in
         <option>networking.useDHCP</option> is true, then every
         interface not listed here will be configured using DHCP.
       '';
-      type = with types; loaOf (submodule interfaceOpts);
+      type = with types; attrsOf (submodule interfaceOpts);
     };
 
     networking.vswitches = mkOption {
@@ -541,7 +544,7 @@ in
           interfaces = mkOption {
             example = [ "eth0" "eth1" ];
             description = "The physical network interfaces connected by the vSwitch.";
-            type = with types; loaOf (submodule vswitchInterfaceOpts);
+            type = with types; attrsOf (submodule vswitchInterfaceOpts);
           };
 
           controllers = mkOption {
@@ -1126,7 +1129,6 @@ in
       ++ optionals config.networking.wireless.enable [
         pkgs.wirelesstools # FIXME: obsolete?
         pkgs.iw
-        pkgs.rfkill
       ]
       ++ bridgeStp;
 
diff --git a/nixos/modules/testing/test-instrumentation.nix b/nixos/modules/testing/test-instrumentation.nix
index 1baeab53b0c2d..c0ec76e8a3a35 100644
--- a/nixos/modules/testing/test-instrumentation.nix
+++ b/nixos/modules/testing/test-instrumentation.nix
@@ -1,22 +1,13 @@
 # This module allows the test driver to connect to the virtual machine
 # via a root shell attached to port 514.
 
-{ config, lib, pkgs, ... }:
+{ options, config, lib, pkgs, ... }:
 
 with lib;
 with import ../../lib/qemu-flags.nix { inherit pkgs; };
 
 {
 
-  # This option is a dummy that if used in conjunction with
-  # modules/virtualisation/qemu-vm.nix gets merged with the same option defined
-  # there and only is declared here because some modules use
-  # test-instrumentation.nix but not qemu-vm.nix.
-  #
-  # One particular example are the boot tests where we want instrumentation
-  # within the images but not other stuff like setting up 9p filesystems.
-  options.virtualisation.qemu = { };
-
   config = {
 
     systemd.services.backdoor =
@@ -55,7 +46,12 @@ with import ../../lib/qemu-flags.nix { inherit pkgs; };
     systemd.services."serial-getty@hvc0".enable = false;
 
     # Only use a serial console, no TTY.
-    virtualisation.qemu.consoles = [ qemuSerialDevice ];
+    # NOTE: optionalAttrs
+    #       test-instrumentation.nix appears to be used without qemu-vm.nix, so
+    #       we avoid defining consoles if not possible.
+    # TODO: refactor such that test-instrumentation can import qemu-vm
+    #       or declare virtualisation.qemu.console option in a module that's always imported
+    virtualisation = lib.optionalAttrs (options ? virtualisation.qemu.consoles) { qemu.consoles = [ qemuSerialDevice ]; };
 
     boot.initrd.preDeviceCommands =
       ''
@@ -78,15 +74,8 @@ with import ../../lib/qemu-flags.nix { inherit pkgs; };
         # OOM killer randomly get rid of processes, since this leads
         # to failures that are hard to diagnose.
         echo 2 > /proc/sys/vm/panic_on_oom
-
-        # Coverage data is written into /tmp/coverage-data.
-        mkdir -p /tmp/xchg/coverage-data
       '';
 
-    # If the kernel has been built with coverage instrumentation, make
-    # it available under /proc/gcov.
-    boot.kernelModules = [ "gcov-proc" ];
-
     # Panic if an error occurs in stage 1 (rather than waiting for
     # user intervention).
     boot.kernelParams =
@@ -115,8 +104,6 @@ with import ../../lib/qemu-flags.nix { inherit pkgs; };
     networking.defaultGateway = mkOverride 150 "";
     networking.nameservers = mkOverride 150 [ ];
 
-    systemd.globalEnvironment.GCOV_PREFIX = "/tmp/xchg/coverage-data";
-
     system.requiredKernelConfig = with config.lib.kernelConfig; [
       (isYes "SERIAL_8250_CONSOLE")
       (isYes "SERIAL_8250")
diff --git a/nixos/modules/virtualisation/azure-image.nix b/nixos/modules/virtualisation/azure-image.nix
index 21fd58e5c9024..60fed3222ef3a 100644
--- a/nixos/modules/virtualisation/azure-image.nix
+++ b/nixos/modules/virtualisation/azure-image.nix
@@ -6,7 +6,7 @@ let
 in
 {
   imports = [ ./azure-common.nix ];
-  
+
   options = {
     virtualisation.azureImage.diskSize = mkOption {
       type = with types; int;
diff --git a/nixos/modules/virtualisation/containers.nix b/nixos/modules/virtualisation/containers.nix
index 7d184575640b6..de97ba3f7bb0c 100644
--- a/nixos/modules/virtualisation/containers.nix
+++ b/nixos/modules/virtualisation/containers.nix
@@ -23,6 +23,15 @@ in
     maintainers = [] ++ lib.teams.podman.members;
   };
 
+
+  imports = [
+    (
+      lib.mkRemovedOptionModule
+      [ "virtualisation" "containers" "users" ]
+      "All users with `isNormalUser = true` set now get appropriate subuid/subgid mappings."
+    )
+  ];
+
   options.virtualisation.containers = {
 
     enable =
@@ -34,6 +43,31 @@ in
         '';
       };
 
+    ociSeccompBpfHook.enable = mkOption {
+      type = types.bool;
+      default = false;
+      description = "Enable the OCI seccomp BPF hook";
+    };
+
+    containersConf = mkOption {
+      default = {};
+      description = "containers.conf configuration";
+      type = types.submodule {
+        options = {
+
+          extraConfig = mkOption {
+            type = types.lines;
+            default = "";
+            description = ''
+              Extra configuration that should be put in the containers.conf
+              configuration file
+            '';
+
+          };
+        };
+      };
+    };
+
     registries = {
       search = mkOption {
         type = types.listOf types.str;
@@ -80,43 +114,26 @@ in
       '';
     };
 
-    users = mkOption {
-      default = [];
-      type = types.listOf types.str;
-      description = ''
-        List of users to set up subuid/subgid mappings for.
-        This is a requirement for running rootless containers.
-      '';
-    };
-
   };
 
   config = lib.mkIf cfg.enable {
 
+    environment.etc."containers/containers.conf".text = ''
+      [network]
+      cni_plugin_dirs = ["${pkgs.cni-plugins}/bin/"]
+
+      ${lib.optionalString (cfg.ociSeccompBpfHook.enable == true) ''
+      [engine]
+      hooks_dir = [
+        "${config.boot.kernelPackages.oci-seccomp-bpf-hook}",
+      ]
+      ''}
+    '' + cfg.containersConf.extraConfig;
+
     environment.etc."containers/registries.conf".source = toTOML "registries.conf" {
       registries = lib.mapAttrs (n: v: { registries = v; }) cfg.registries;
     };
 
-    users.extraUsers = builtins.listToAttrs (
-      (
-        builtins.foldl' (
-          acc: user: {
-            values = acc.values ++ [
-              {
-                name = user;
-                value = {
-                  subUidRanges = [ { startUid = acc.offset; count = 65536; } ];
-                  subGidRanges = [ { startGid = acc.offset; count = 65536; } ];
-                };
-              }
-            ];
-            offset = acc.offset + 65536;
-          }
-        )
-        { values = []; offset = 100000; } (lib.unique cfg.users)
-      ).values
-    );
-
     environment.etc."containers/policy.json".source =
       if cfg.policy != {} then pkgs.writeText "policy.json" (builtins.toJSON cfg.policy)
       else copyFile "${pkgs.skopeo.src}/default-policy.json";
diff --git a/nixos/modules/virtualisation/cri-o.nix b/nixos/modules/virtualisation/cri-o.nix
index f267c97b17889..70e7c8794d438 100644
--- a/nixos/modules/virtualisation/cri-o.nix
+++ b/nixos/modules/virtualisation/cri-o.nix
@@ -85,7 +85,7 @@ in
 
     environment.etc."crictl.yaml".source = copyFile "${pkgs.cri-o-unwrapped.src}/crictl.yaml";
 
-    environment.etc."crio/crio.conf".text = ''
+    environment.etc."crio/crio.conf.d/00-default.conf".text = ''
       [crio]
       storage_driver = "${cfg.storageDriver}"
 
@@ -99,7 +99,8 @@ in
       [crio.runtime]
       cgroup_manager = "systemd"
       log_level = "${cfg.logLevel}"
-      manage_ns_lifecycle = true
+      pinns_path = "${cfg.package}/bin/pinns"
+      hooks_dir = []
 
       ${optionalString (cfg.runtime != null) ''
       default_runtime = "${cfg.runtime}"
@@ -109,6 +110,7 @@ in
     '';
 
     environment.etc."cni/net.d/10-crio-bridge.conf".source = copyFile "${pkgs.cri-o-unwrapped.src}/contrib/cni/10-crio-bridge.conf";
+    environment.etc."cni/net.d/99-loopback.conf".source = copyFile "${pkgs.cri-o-unwrapped.src}/contrib/cni/99-loopback.conf";
 
     # Enable common /etc/containers configuration
     virtualisation.containers.enable = true;
diff --git a/nixos/modules/virtualisation/docker-preloader.nix b/nixos/modules/virtualisation/docker-preloader.nix
deleted file mode 100644
index 6ab83058dee1d..0000000000000
--- a/nixos/modules/virtualisation/docker-preloader.nix
+++ /dev/null
@@ -1,134 +0,0 @@
-{ config, lib, pkgs, ... }:
-
-with lib;
-with builtins;
-
-let
-  cfg = config.virtualisation;
-
-  sanitizeImageName = image: replaceStrings ["/"] ["-"] image.imageName;
-  hash = drv: head (split "-" (baseNameOf drv.outPath));
-  # The label of an ext4 FS is limited to 16 bytes
-  labelFromImage = image: substring 0 16 (hash image);
-
-  # The Docker image is loaded and some files from /var/lib/docker/
-  # are written into a qcow image.
-  preload = image: pkgs.vmTools.runInLinuxVM (
-    pkgs.runCommand "docker-preload-image-${sanitizeImageName image}" {
-      buildInputs = with pkgs; [ docker e2fsprogs utillinux curl kmod ];
-      preVM = pkgs.vmTools.createEmptyImage {
-        size = cfg.dockerPreloader.qcowSize;
-        fullName = "docker-deamon-image.qcow2";
-      };
-    }
-    ''
-      mkfs.ext4 /dev/vda
-      e2label /dev/vda ${labelFromImage image}
-      mkdir -p /var/lib/docker
-      mount -t ext4 /dev/vda /var/lib/docker
-
-      modprobe overlay
-
-      # from https://github.com/tianon/cgroupfs-mount/blob/master/cgroupfs-mount
-      mount -t tmpfs -o uid=0,gid=0,mode=0755 cgroup /sys/fs/cgroup
-      cd /sys/fs/cgroup
-      for sys in $(awk '!/^#/ { if ($4 == 1) print $1 }' /proc/cgroups); do
-        mkdir -p $sys
-        if ! mountpoint -q $sys; then
-          if ! mount -n -t cgroup -o $sys cgroup $sys; then
-            rmdir $sys || true
-          fi
-        fi
-      done
-
-      dockerd -H tcp://127.0.0.1:5555 -H unix:///var/run/docker.sock &
-
-      until $(curl --output /dev/null --silent --connect-timeout 2 http://127.0.0.1:5555); do
-        printf '.'
-        sleep 1
-      done
-
-      docker load -i ${image}
-
-      kill %1
-      find /var/lib/docker/ -maxdepth 1 -mindepth 1 -not -name "image" -not -name "overlay2" | xargs rm -rf
-    '');
-
-  preloadedImages = map preload cfg.dockerPreloader.images;
-
-in
-
-{
-  options.virtualisation.dockerPreloader = {
-    images = mkOption {
-      default = [ ];
-      type = types.listOf types.package;
-      description =
-      ''
-        A list of Docker images to preload (in the /var/lib/docker directory).
-      '';
-    };
-    qcowSize = mkOption {
-      default = 1024;
-      type = types.int;
-      description =
-      ''
-        The size (MB) of qcow files.
-      '';
-    };
-  };
-
-  config = mkIf (cfg.dockerPreloader.images != []) {
-    assertions = [{
-      # If docker.storageDriver is null, Docker choose the storage
-      # driver. So, in this case, we cannot be sure overlay2 is used.
-      assertion = cfg.docker.storageDriver == "overlay2"
-        || cfg.docker.storageDriver == "overlay"
-        || cfg.docker.storageDriver == null;
-      message = "The Docker image Preloader only works with overlay2 storage driver!";
-    }];
-
-    virtualisation.qemu.options =
-      map (path: "-drive if=virtio,file=${path}/disk-image.qcow2,readonly,media=cdrom,format=qcow2")
-      preloadedImages;
-
-
-    # All attached QCOW files are mounted and their contents are linked
-    # to /var/lib/docker/ in order to make image available.
-    systemd.services.docker-preloader = {
-      description = "Preloaded Docker images";
-      wantedBy = ["docker.service"];
-      after = ["network.target"];
-      path = with pkgs; [ mount rsync jq ];
-      script = ''
-        mkdir -p /var/lib/docker/overlay2/l /var/lib/docker/image/overlay2
-        echo '{}' > /tmp/repositories.json
-
-        for i in ${concatStringsSep " " (map labelFromImage cfg.dockerPreloader.images)}; do
-          mkdir -p /mnt/docker-images/$i
-
-          # The ext4 label is limited to 16 bytes
-          mount /dev/disk/by-label/$(echo $i | cut -c1-16) -o ro,noload /mnt/docker-images/$i
-
-          find /mnt/docker-images/$i/overlay2/ -maxdepth 1 -mindepth 1 -not -name l\
-             -exec ln -s '{}' /var/lib/docker/overlay2/ \;
-          cp -P /mnt/docker-images/$i/overlay2/l/* /var/lib/docker/overlay2/l/
-
-          rsync -a /mnt/docker-images/$i/image/ /var/lib/docker/image/
-
-          # Accumulate image definitions
-          cp /tmp/repositories.json /tmp/repositories.json.tmp
-          jq -s '.[0] * .[1]' \
-            /tmp/repositories.json.tmp \
-            /mnt/docker-images/$i/image/overlay2/repositories.json \
-            > /tmp/repositories.json
-        done
-
-        mv /tmp/repositories.json /var/lib/docker/image/overlay2/repositories.json
-      '';
-      serviceConfig = {
-        Type = "oneshot";
-      };
-    };
-  };
-}
diff --git a/nixos/modules/virtualisation/docker.nix b/nixos/modules/virtualisation/docker.nix
index 7d196a46276ac..d87ada35a0ae4 100644
--- a/nixos/modules/virtualisation/docker.nix
+++ b/nixos/modules/virtualisation/docker.nix
@@ -149,6 +149,7 @@ in
   ###### implementation
 
   config = mkIf cfg.enable (mkMerge [{
+      boot.kernelModules = [ "bridge" "veth" ];
       environment.systemPackages = [ cfg.package ]
         ++ optional cfg.enableNvidia pkgs.nvidia-docker;
       users.groups.docker.gid = config.ids.gids.docker;
diff --git a/nixos/modules/virtualisation/libvirtd.nix b/nixos/modules/virtualisation/libvirtd.nix
index 43b5fcfa8fae5..1d6a9457dde41 100644
--- a/nixos/modules/virtualisation/libvirtd.nix
+++ b/nixos/modules/virtualisation/libvirtd.nix
@@ -265,8 +265,8 @@ in {
       restartIfChanged = false;
     };
 
-    systemd.sockets.libvirtd    .wantedBy = [ "sockets.target" ];
-    systemd.sockets.libvirtd-tcp.wantedBy = [ "sockets.target" ];
+    # https://libvirt.org/daemons.html#monolithic-systemd-integration
+    systemd.sockets.libvirtd.wantedBy = [ "sockets.target" ];
 
     security.polkit.extraConfig = ''
       polkit.addRule(function(action, subject) {
diff --git a/nixos/modules/virtualisation/nixos-containers.nix b/nixos/modules/virtualisation/nixos-containers.nix
index b0fa03917c822..8fbb4efd20196 100644
--- a/nixos/modules/virtualisation/nixos-containers.nix
+++ b/nixos/modules/virtualisation/nixos-containers.nix
@@ -627,7 +627,7 @@ in
 		    };
 
             bindMounts = mkOption {
-              type = with types; loaOf (submodule bindMountOpts);
+              type = with types; attrsOf (submodule bindMountOpts);
               default = {};
               example = literalExample ''
                 { "/home" = { hostPath = "/home/alice";
diff --git a/nixos/modules/virtualisation/parallels-guest.nix b/nixos/modules/virtualisation/parallels-guest.nix
index 828419fb4b9d7..55605b388b7ca 100644
--- a/nixos/modules/virtualisation/parallels-guest.nix
+++ b/nixos/modules/virtualisation/parallels-guest.nix
@@ -32,7 +32,7 @@ in
       };
 
       package = mkOption {
-        type = types.package;
+        type = types.nullOr types.package;
         default = config.boot.kernelPackages.prl-tools;
         defaultText = "config.boot.kernelPackages.prl-tools";
         example = literalExample "config.boot.kernelPackages.prl-tools";
diff --git a/nixos/modules/virtualisation/podman.nix b/nixos/modules/virtualisation/podman.nix
index 652850bf5006b..e0e2f04e24c18 100644
--- a/nixos/modules/virtualisation/podman.nix
+++ b/nixos/modules/virtualisation/podman.nix
@@ -28,6 +28,10 @@ let
 
 in
 {
+  imports = [
+    (lib.mkRenamedOptionModule [ "virtualisation" "podman" "libpod" ] [ "virtualisation" "containers" "containersConf" ])
+  ];
+
   meta = {
     maintainers = lib.teams.podman.members;
   };
@@ -67,25 +71,6 @@ in
       '';
     };
 
-    libpod = mkOption {
-      default = {};
-      description = "Libpod configuration";
-      type = types.submodule {
-        options = {
-
-          extraConfig = mkOption {
-            type = types.lines;
-            default = "";
-            description = ''
-              Extra configuration that should be put in the libpod.conf
-              configuration file
-            '';
-
-          };
-        };
-      };
-    };
-
     package = lib.mkOption {
       type = types.package;
       default = podmanPackage;
@@ -103,11 +88,6 @@ in
     environment.systemPackages = [ cfg.package ]
       ++ lib.optional cfg.dockerCompat dockerCompat;
 
-    environment.etc."containers/libpod.conf".text = ''
-      cni_plugin_dir = ["${pkgs.cni-plugins}/bin/"]
-
-    '' + cfg.libpod.extraConfig;
-
     environment.etc."cni/net.d/87-podman-bridge.conflist".source = copyFile "${pkgs.podman-unwrapped.src}/cni/87-podman-bridge.conflist";
 
     # Enable common /etc/containers configuration
diff --git a/nixos/modules/virtualisation/qemu-vm.nix b/nixos/modules/virtualisation/qemu-vm.nix
index be06d6feb11f3..42e43f5ee0233 100644
--- a/nixos/modules/virtualisation/qemu-vm.nix
+++ b/nixos/modules/virtualisation/qemu-vm.nix
@@ -16,11 +16,6 @@ let
 
   qemu = config.system.build.qemu or pkgs.qemu_test;
 
-  vmName =
-    if config.networking.hostName == ""
-    then "noname"
-    else config.networking.hostName;
-
   cfg = config.virtualisation;
 
   consoles = lib.concatMapStringsSep " " (c: "console=${c}") cfg.qemu.consoles;
@@ -46,6 +41,13 @@ let
         description = "Extra options passed to device flag.";
       };
 
+      name = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description =
+          "A name for the drive. Must be unique in the drives list. Not passed to qemu.";
+      };
+
     };
 
   };
@@ -74,6 +76,32 @@ let
 
   drivesCmdLine = drives: concatStringsSep " " (imap1 driveCmdline drives);
 
+
+  # Creates a device name from a 1-based a numerical index, e.g.
+  # * `driveDeviceName 1` -> `/dev/vda`
+  # * `driveDeviceName 2` -> `/dev/vdb`
+  driveDeviceName = idx:
+    let letter = elemAt lowerChars (idx - 1);
+    in if cfg.qemu.diskInterface == "scsi" then
+      "/dev/sd${letter}"
+    else
+      "/dev/vd${letter}";
+
+  lookupDriveDeviceName = driveName: driveList:
+    (findSingle (drive: drive.name == driveName)
+      (throw "Drive ${driveName} not found")
+      (throw "Multiple drives named ${driveName}") driveList).device;
+
+  addDeviceNames =
+    imap1 (idx: drive: drive // { device = driveDeviceName idx; });
+
+  efiPrefix =
+    if (pkgs.stdenv.isi686 || pkgs.stdenv.isx86_64) then "${pkgs.OVMF.fd}/FV/OVMF"
+    else if pkgs.stdenv.isAarch64 then "${pkgs.OVMF.fd}/FV/AAVMF"
+    else throw "No EFI firmware available for platform";
+  efiFirmware = "${efiPrefix}_CODE.fd";
+  efiVarsDefault = "${efiPrefix}_VARS.fd";
+
   # Shell script to start the VM.
   startVM =
     ''
@@ -99,10 +127,14 @@ let
         # A writable boot disk can be booted from automatically.
         ${qemu}/bin/qemu-img create -f qcow2 -b ${bootDisk}/disk.img $TMPDIR/disk.img || exit 1
 
+        NIX_EFI_VARS=$(readlink -f ''${NIX_EFI_VARS:-${cfg.efiVars}})
+
         ${if cfg.useEFIBoot then ''
-          # VM needs a writable flash BIOS.
-          cp ${bootDisk}/bios.bin $TMPDIR || exit 1
-          chmod 0644 $TMPDIR/bios.bin || exit 1
+          # VM needs writable EFI vars
+          if ! test -e "$NIX_EFI_VARS"; then
+            cp ${bootDisk}/efi-vars.fd "$NIX_EFI_VARS" || exit 1
+            chmod 0644 "$NIX_EFI_VARS" || exit 1
+          fi
         '' else ''
         ''}
       '' else ''
@@ -119,7 +151,7 @@ let
 
       # Start QEMU.
       exec ${qemuBinary qemu} \
-          -name ${vmName} \
+          -name ${config.system.name} \
           -m ${toString config.virtualisation.memorySize} \
           -smp ${toString config.virtualisation.cores} \
           -device virtio-rng-pci \
@@ -139,6 +171,8 @@ let
 
   # Generate a hard disk image containing a /boot partition and GRUB
   # in the MBR.  Used when the `useBootLoader' option is set.
+  # Uses `runInLinuxVM` to create the image in a throwaway VM.
+  # See note [Disk layout with `useBootLoader`].
   # FIXME: use nixos/lib/make-disk-image.nix.
   bootDisk =
     pkgs.vmTools.runInLinuxVM (
@@ -147,21 +181,22 @@ let
             ''
               mkdir $out
               diskImage=$out/disk.img
-              bootFlash=$out/bios.bin
-              ${qemu}/bin/qemu-img create -f qcow2 $diskImage "40M"
+              ${qemu}/bin/qemu-img create -f qcow2 $diskImage "60M"
               ${if cfg.useEFIBoot then ''
-                cp ${pkgs.OVMF-CSM.fd}/FV/OVMF.fd $bootFlash
-                chmod 0644 $bootFlash
+                efiVars=$out/efi-vars.fd
+                cp ${efiVarsDefault} $efiVars
+                chmod 0644 $efiVars
               '' else ''
               ''}
             '';
           buildInputs = [ pkgs.utillinux ];
-          QEMU_OPTS = if cfg.useEFIBoot
-                      then "-pflash $out/bios.bin -nographic -serial pty"
-                      else "-nographic -serial pty";
+          QEMU_OPTS = "-nographic -serial stdio -monitor none"
+                      + lib.optionalString cfg.useEFIBoot (
+                        " -drive if=pflash,format=raw,unit=0,readonly=on,file=${efiFirmware}"
+                      + " -drive if=pflash,format=raw,unit=1,file=$efiVars");
         }
         ''
-          # Create a /boot EFI partition with 40M and arbitrary but fixed GUIDs for reproducibility
+          # Create a /boot EFI partition with 60M and arbitrary but fixed GUIDs for reproducibility
           ${pkgs.gptfdisk}/bin/sgdisk \
             --set-alignment=1 --new=1:34:2047 --change-name=1:BIOSBootPartition --typecode=1:ef02 \
             --set-alignment=512 --largest-new=2 --change-name=2:EFISystem --typecode=2:ef00 \
@@ -172,6 +207,19 @@ let
             --partition-guid=2:970C694F-AFD0-4B99-B750-CDB7A329AB6F \
             --hybrid 2 \
             --recompute-chs /dev/vda
+
+          ${optionalString (config.boot.loader.grub.device != "/dev/vda")
+            # In this throwaway VM, we only have the /dev/vda disk, but the
+            # actual VM described by `config` (used by `switch-to-configuration`
+            # below) may set `boot.loader.grub.device` to a different device
+            # that's nonexistent in the throwaway VM.
+            # Create a symlink for that device, so that the `grub-install`
+            # by `switch-to-configuration` will hit /dev/vda anyway.
+            ''
+              ln -s /dev/vda ${config.boot.loader.grub.device}
+            ''
+          }
+
           ${pkgs.dosfstools}/bin/mkfs.fat -F16 /dev/vda2
           export MTOOLS_SKIP_CHECK=1
           ${pkgs.mtools}/bin/mlabel -i /dev/vda2 ::boot
@@ -185,6 +233,10 @@ let
           mkdir /boot
           mount /dev/vda2 /boot
 
+          ${optionalString config.boot.loader.efi.canTouchEfiVariables ''
+            mount -t efivarfs efivarfs /sys/firmware/efi/efivars
+          ''}
+
           # This is needed for GRUB 0.97, which doesn't know about virtio devices.
           mkdir /boot/grub
           echo '(hd0) /dev/vda' > /boot/grub/device.map
@@ -212,7 +264,6 @@ in
 {
   imports = [
     ../profiles/qemu-guest.nix
-   ./docker-preloader.nix
   ];
 
   options = {
@@ -237,7 +288,7 @@ in
 
     virtualisation.diskImage =
       mkOption {
-        default = "./${vmName}.qcow2";
+        default = "./${config.system.name}.qcow2";
         description =
           ''
             Path to the disk image containing the root filesystem.
@@ -396,6 +447,7 @@ in
         mkOption {
           type = types.listOf (types.submodule driveOpts);
           description = "Drives passed to qemu.";
+          apply = addDeviceNames;
         };
 
       diskInterface =
@@ -441,6 +493,16 @@ in
           '';
       };
 
+    virtualisation.efiVars =
+      mkOption {
+        default = "./${config.system.name}-efi-vars.fd";
+        description =
+          ''
+            Path to nvram image containing UEFI variables.  The will be created
+            on startup if it does not exist.
+          '';
+      };
+
     virtualisation.bios =
       mkOption {
         default = null;
@@ -457,7 +519,27 @@ in
 
   config = {
 
-    boot.loader.grub.device = mkVMOverride cfg.bootDevice;
+    # Note [Disk layout with `useBootLoader`]
+    #
+    # If `useBootLoader = true`, we configure 2 drives:
+    # `/dev/?da` for the root disk, and `/dev/?db` for the boot disk
+    # which has the `/boot` partition and the boot loader.
+    # Concretely:
+    #
+    # * The second drive's image `disk.img` is created in `bootDisk = ...`
+    #   using a throwaway VM. Note that there the disk is always `/dev/vda`,
+    #   even though in the final VM it will be at `/dev/*b`.
+    # * The disks are attached in `virtualisation.qemu.drives`.
+    #   Their order makes them appear as devices `a`, `b`, etc.
+    # * `fileSystems."/boot"` is adjusted to be on device `b`.
+
+    # If `useBootLoader`, GRUB goes to the second disk, see
+    # note [Disk layout with `useBootLoader`].
+    boot.loader.grub.device = mkVMOverride (
+      if cfg.useBootLoader
+        then driveDeviceName 2 # second disk
+        else cfg.bootDevice
+    );
 
     boot.initrd.extraUtilsCommands =
       ''
@@ -512,8 +594,7 @@ in
       optional cfg.writableStore "overlay"
       ++ optional (cfg.qemu.diskInterface == "scsi") "sym53c8xx";
 
-    virtualisation.bootDevice =
-      mkDefault (if cfg.qemu.diskInterface == "scsi" then "/dev/sda" else "/dev/vda");
+    virtualisation.bootDevice = mkDefault (driveDeviceName 1);
 
     virtualisation.pathsInNixDB = [ config.system.build.toplevel ];
 
@@ -531,7 +612,8 @@ in
         ''-append "$(cat ${config.system.build.toplevel}/kernel-params) init=${config.system.build.toplevel}/init regInfo=${regInfo}/registration ${consoles} $QEMU_KERNEL_PARAMS"''
       ])
       (mkIf cfg.useEFIBoot [
-        "-pflash $TMPDIR/bios.bin"
+        "-drive if=pflash,format=raw,unit=0,readonly,file=${efiFirmware}"
+        "-drive if=pflash,format=raw,unit=1,file=$NIX_EFI_VARS"
       ])
       (mkIf (cfg.bios != null) [
         "-bios ${cfg.bios}/bios.bin"
@@ -542,25 +624,22 @@ in
     ];
 
     virtualisation.qemu.drives = mkMerge [
+      [{
+        name = "root";
+        file = "$NIX_DISK_IMAGE";
+        driveExtraOpts.cache = "writeback";
+        driveExtraOpts.werror = "report";
+      }]
       (mkIf cfg.useBootLoader [
+        # The order of this list determines the device names, see
+        # note [Disk layout with `useBootLoader`].
         {
-          file = "$NIX_DISK_IMAGE";
-          driveExtraOpts.cache = "writeback";
-          driveExtraOpts.werror = "report";
-        }
-        {
+          name = "boot";
           file = "$TMPDIR/disk.img";
           driveExtraOpts.media = "disk";
           deviceExtraOpts.bootindex = "1";
         }
       ])
-      (mkIf (!cfg.useBootLoader) [
-        {
-          file = "$NIX_DISK_IMAGE";
-          driveExtraOpts.cache = "writeback";
-          driveExtraOpts.werror = "report";
-        }
-      ])
       (imap0 (idx: _: {
         file = "$(pwd)/empty${toString idx}.qcow2";
         driveExtraOpts.werror = "report";
@@ -608,9 +687,9 @@ in
           };
       } // optionalAttrs cfg.useBootLoader
       { "/boot" =
-          { device = "/dev/vdb2";
+          # see note [Disk layout with `useBootLoader`]
+          { device = "${lookupDriveDeviceName "boot" cfg.qemu.drives}2"; # 2 for e.g. `vdb2`, as created in `bootDisk`
             fsType = "vfat";
-            options = [ "ro" ];
             noCheck = true; # fsck fails on a r/o filesystem
           };
       });
@@ -627,7 +706,7 @@ in
       ''
         mkdir -p $out/bin
         ln -s ${config.system.build.toplevel} $out/system
-        ln -s ${pkgs.writeScript "run-nixos-vm" startVM} $out/bin/run-${vmName}-vm
+        ln -s ${pkgs.writeScript "run-nixos-vm" startVM} $out/bin/run-${config.system.name}-vm
       '';
 
     # When building a regular system configuration, override whatever
diff --git a/nixos/modules/virtualisation/railcar.nix b/nixos/modules/virtualisation/railcar.nix
index 12da1c75fc38c..10464f6289846 100644
--- a/nixos/modules/virtualisation/railcar.nix
+++ b/nixos/modules/virtualisation/railcar.nix
@@ -29,9 +29,9 @@ let
         default = "none";
         description = ''
           The type of the filesystem to be mounted.
-          Linux: filesystem types supported by the kernel as listed in 
-          `/proc/filesystems` (e.g., "minix", "ext2", "ext3", "jfs", "xfs", 
-          "reiserfs", "msdos", "proc", "nfs", "iso9660"). For bind mounts 
+          Linux: filesystem types supported by the kernel as listed in
+          `/proc/filesystems` (e.g., "minix", "ext2", "ext3", "jfs", "xfs",
+          "reiserfs", "msdos", "proc", "nfs", "iso9660"). For bind mounts
           (when options include either bind or rbind), the type is a dummy,
           often "none" (not listed in /proc/filesystems).
         '';
@@ -41,13 +41,13 @@ let
         description = "Source for the in-container mount";
       };
       options = mkOption {
-        type = loaOf (str);
+        type = attrsOf (str);
         default = [ "bind" ];
         description = ''
           Mount options of the filesystem to be used.
-        
-          Support optoions are listed in the mount(8) man page. Note that 
-          both filesystem-independent and filesystem-specific options 
+
+          Support options are listed in the mount(8) man page. Note that
+          both filesystem-independent and filesystem-specific options
           are listed.
         '';
       };
@@ -61,7 +61,7 @@ in
     containers = mkOption {
       default = {};
       description = "Declarative container configuration";
-      type = with types; loaOf (submodule ({ name, config, ... }: {
+      type = with types; attrsOf (submodule ({ name, config, ... }: {
         options = {
           cmd = mkOption {
             type = types.lines;
diff --git a/nixos/modules/virtualisation/spice-usb-redirection.nix b/nixos/modules/virtualisation/spice-usb-redirection.nix
new file mode 100644
index 0000000000000..4168cebe79b18
--- /dev/null
+++ b/nixos/modules/virtualisation/spice-usb-redirection.nix
@@ -0,0 +1,24 @@
+{ config, pkgs, lib, ... }:
+{
+  options.virtualisation.spiceUSBRedirection.enable = lib.mkOption {
+    type = lib.types.bool;
+    default = false;
+    description = ''
+      Install the SPICE USB redirection helper with setuid
+      privileges. This allows unprivileged users to pass USB devices
+      connected to this machine to libvirt VMs, both local and
+      remote. Note that this allows users arbitrary access to USB
+      devices.
+    '';
+  };
+
+  config = lib.mkIf config.virtualisation.spiceUSBRedirection.enable {
+    environment.systemPackages = [ pkgs.spice-gtk ]; # For polkit actions
+    security.wrappers.spice-client-glib-usb-acl-helper ={
+      source = "${pkgs.spice-gtk}/bin/spice-client-glib-usb-acl-helper";
+      capabilities = "cap_fowner+ep";
+    };
+  };
+
+  meta.maintainers = [ lib.maintainers.lheckemann ];
+}
diff --git a/nixos/modules/virtualisation/virtualbox-guest.nix b/nixos/modules/virtualisation/virtualbox-guest.nix
index 834b994e92d2a..486951983d303 100644
--- a/nixos/modules/virtualisation/virtualbox-guest.nix
+++ b/nixos/modules/virtualisation/virtualbox-guest.nix
@@ -68,7 +68,7 @@ in
         SUBSYSTEM=="misc", KERNEL=="vboxguest", TAG+="systemd"
       '';
   } (mkIf cfg.x11 {
-    services.xserver.videoDrivers = mkOverride 50 [ "virtualbox" "modesetting" ];
+    services.xserver.videoDrivers = mkOverride 50 [ "vmware" "virtualbox" "modesetting" ];
 
     services.xserver.config =
       ''
diff --git a/nixos/modules/virtualisation/virtualbox-image.nix b/nixos/modules/virtualisation/virtualbox-image.nix
index 788b4d9d9761d..fa580e8b42d6b 100644
--- a/nixos/modules/virtualisation/virtualbox-image.nix
+++ b/nixos/modules/virtualisation/virtualbox-image.nix
@@ -58,6 +58,35 @@ in {
           Run <literal>VBoxManage modifyvm --help</literal> to see more options.
         '';
      };
+      extraDisk = mkOption {
+        description = ''
+          Optional extra disk/hdd configuration.
+          The disk will be an 'ext4' partition on a separate VMDK file.
+        '';
+        default = null;
+        example = {
+          label = "storage";
+          mountPoint = "/home/demo/storage";
+          size = 100 * 1024;
+        };
+        type = types.nullOr (types.submodule {
+          options = {
+            size = mkOption {
+              type = types.int;
+              description = "Size in MiB";
+            };
+            label = mkOption {
+              type = types.str;
+              default = "vm-extra-storage";
+              description = "Label for the disk partition";
+            };
+            mountPoint = mkOption {
+              type = types.str;
+              description = "Path where to mount this disk.";
+            };
+          };
+        });
+      };
     };
   };
 
@@ -72,6 +101,7 @@ in {
         audiocontroller = "ac97";
         audio = "alsa";
         audioout = "on";
+        graphicscontroller = "vmsvga";
         rtcuseutc = "on";
         usb = "on";
         usbehci = "on";
@@ -95,6 +125,20 @@ in {
           echo "creating VirtualBox pass-through disk wrapper (no copying involved)..."
           VBoxManage internalcommands createrawvmdk -filename disk.vmdk -rawdisk $diskImage
 
+          ${optionalString (cfg.extraDisk != null) ''
+            echo "creating extra disk: data-disk.raw"
+            dataDiskImage=data-disk.raw
+            truncate -s ${toString cfg.extraDisk.size}M $dataDiskImage
+
+            parted --script $dataDiskImage -- \
+              mklabel msdos \
+              mkpart primary ext4 1MiB -1
+            eval $(partx $dataDiskImage -o START,SECTORS --nr 1 --pairs)
+            mkfs.ext4 -F -L ${cfg.extraDisk.label} $dataDiskImage -E offset=$(sectorsToBytes $START) $(sectorsToKilobytes $SECTORS)K
+            echo "creating extra disk: data-disk.vmdk"
+            VBoxManage internalcommands createrawvmdk -filename data-disk.vmdk -rawdisk $dataDiskImage
+          ''}
+
           echo "creating VirtualBox VM..."
           vmName="${cfg.vmName}";
           VBoxManage createvm --name "$vmName" --register \
@@ -105,6 +149,10 @@ in {
           VBoxManage storagectl "$vmName" --name SATA --add sata --portcount 4 --bootable on --hostiocache on
           VBoxManage storageattach "$vmName" --storagectl SATA --port 0 --device 0 --type hdd \
             --medium disk.vmdk
+          ${optionalString (cfg.extraDisk != null) ''
+            VBoxManage storageattach "$vmName" --storagectl SATA --port 1 --device 0 --type hdd \
+            --medium data-disk.vmdk
+          ''}
 
           echo "exporting VirtualBox VM..."
           mkdir -p $out
@@ -118,11 +166,19 @@ in {
         '';
     };
 
-    fileSystems."/" = {
-      device = "/dev/disk/by-label/nixos";
-      autoResize = true;
-      fsType = "ext4";
-    };
+    fileSystems = {
+      "/" = {
+        device = "/dev/disk/by-label/nixos";
+        autoResize = true;
+        fsType = "ext4";
+      };
+    } // (lib.optionalAttrs (cfg.extraDisk != null) {
+      ${cfg.extraDisk.mountPoint} = {
+        device = "/dev/disk/by-label/" + cfg.extraDisk.label;
+        autoResize = true;
+        fsType = "ext4";
+      };
+    });
 
     boot.growPartition = true;
     boot.loader.grub.device = "/dev/sda";
diff --git a/nixos/release-combined.nix b/nixos/release-combined.nix
index ece2d091f5adb..945ba90e3454c 100644
--- a/nixos/release-combined.nix
+++ b/nixos/release-combined.nix
@@ -106,11 +106,29 @@ in rec {
         (onFullSupported "nixos.tests.networking.scripted.bridge")
         (onFullSupported "nixos.tests.networking.scripted.dhcpOneIf")
         (onFullSupported "nixos.tests.networking.scripted.dhcpSimple")
+        (onFullSupported "nixos.tests.networking.scripted.link")
         (onFullSupported "nixos.tests.networking.scripted.loopback")
         (onFullSupported "nixos.tests.networking.scripted.macvlan")
+        (onFullSupported "nixos.tests.networking.scripted.privacy")
+        (onFullSupported "nixos.tests.networking.scripted.routes")
         (onFullSupported "nixos.tests.networking.scripted.sit")
         (onFullSupported "nixos.tests.networking.scripted.static")
+        (onFullSupported "nixos.tests.networking.scripted.virtual")
         (onFullSupported "nixos.tests.networking.scripted.vlan")
+        (onFullSupported "nixos.tests.networking.networkd.bond")
+        (onFullSupported "nixos.tests.networking.networkd.bridge")
+        (onFullSupported "nixos.tests.networking.networkd.dhcpOneIf")
+        (onFullSupported "nixos.tests.networking.networkd.dhcpSimple")
+        (onFullSupported "nixos.tests.networking.networkd.link")
+        (onFullSupported "nixos.tests.networking.networkd.loopback")
+        # Fails nondeterministically (https://github.com/NixOS/nixpkgs/issues/96709)
+        #(onFullSupported "nixos.tests.networking.networkd.macvlan")
+        (onFullSupported "nixos.tests.networking.networkd.privacy")
+        (onFullSupported "nixos.tests.networking.networkd.routes")
+        (onFullSupported "nixos.tests.networking.networkd.sit")
+        (onFullSupported "nixos.tests.networking.networkd.static")
+        (onFullSupported "nixos.tests.networking.networkd.virtual")
+        (onFullSupported "nixos.tests.networking.networkd.vlan")
         (onFullSupported "nixos.tests.systemd-networkd-ipv6-prefix-delegation")
         (onFullSupported "nixos.tests.nfs3.simple")
         (onFullSupported "nixos.tests.nfs4.simple")
diff --git a/nixos/release.nix b/nixos/release.nix
index cf16986b21360..1f5c158126955 100644
--- a/nixos/release.nix
+++ b/nixos/release.nix
@@ -310,6 +310,11 @@ in rec {
         services.xserver.desktopManager.gnome3.enable = true;
       });
 
+    pantheon = makeClosure ({ ... }:
+      { services.xserver.enable = true;
+        services.xserver.desktopManager.pantheon.enable = true;
+      });
+
     # Linux/Apache/PostgreSQL/PHP stack.
     lapp = makeClosure ({ pkgs, ... }:
       { services.httpd.enable = true;
diff --git a/nixos/tests/3proxy.nix b/nixos/tests/3proxy.nix
index 3e2061d7e42fd..de3056f6710f5 100644
--- a/nixos/tests/3proxy.nix
+++ b/nixos/tests/3proxy.nix
@@ -134,6 +134,10 @@ import ./make-test-python.nix ({ pkgs, ...} : {
   };
 
   testScript = ''
+    start_all()
+
+    peer0.wait_for_unit("network-online.target")
+
     peer1.wait_for_unit("3proxy.service")
     peer1.wait_for_open_port("9999")
 
diff --git a/nixos/tests/acme.nix b/nixos/tests/acme.nix
index fc41dc1eb5ff7..64193ed8498cb 100644
--- a/nixos/tests/acme.nix
+++ b/nixos/tests/acme.nix
@@ -1,29 +1,43 @@
 let
   commonConfig = ./common/acme/client;
 
-  dnsScript = {writeScript, dnsAddress, bash, curl}: writeScript "dns-hook.sh" ''
-    #!${bash}/bin/bash
+  dnsServerIP = nodes: nodes.dnsserver.config.networking.primaryIPAddress;
+
+  dnsScript = {pkgs, nodes}: let
+    dnsAddress = dnsServerIP nodes;
+  in pkgs.writeShellScript "dns-hook.sh" ''
     set -euo pipefail
     echo '[INFO]' "[$2]" 'dns-hook.sh' $*
     if [ "$1" = "present" ]; then
-      ${curl}/bin/curl --data '{"host": "'"$2"'", "value": "'"$3"'"}' http://${dnsAddress}:8055/set-txt
+      ${pkgs.curl}/bin/curl --data '{"host": "'"$2"'", "value": "'"$3"'"}' http://${dnsAddress}:8055/set-txt
     else
-      ${curl}/bin/curl --data '{"host": "'"$2"'"}' http://${dnsAddress}:8055/clear-txt
+      ${pkgs.curl}/bin/curl --data '{"host": "'"$2"'"}' http://${dnsAddress}:8055/clear-txt
     fi
   '';
 
+  documentRoot = pkgs: pkgs.runCommand "docroot" {} ''
+    mkdir -p "$out"
+    echo hello world > "$out/index.html"
+  '';
+
+  vhostBase = pkgs: {
+    forceSSL = true;
+    locations."/".root = documentRoot pkgs;
+  };
+
 in import ./make-test-python.nix ({ lib, ... }: {
   name = "acme";
   meta.maintainers = lib.teams.acme.members;
 
-  nodes = rec {
+  nodes = {
+    # The fake ACME server which will respond to client requests
     acme = { nodes, lib, ... }: {
       imports = [ ./common/acme/server ];
-      networking.nameservers = lib.mkForce [
-        nodes.dnsserver.config.networking.primaryIPAddress
-      ];
+      networking.nameservers = lib.mkForce [ (dnsServerIP nodes) ];
     };
 
+    # A fake DNS server which can be configured with records as desired
+    # Used to test DNS-01 challenge
     dnsserver = { nodes, pkgs, ... }: {
       networking.firewall.allowedTCPPorts = [ 8055 53 ];
       networking.firewall.allowedUDPPorts = [ 53 ];
@@ -39,106 +53,111 @@ in import ./make-test-python.nix ({ lib, ... }: {
       };
     };
 
-    acmeStandalone = { nodes, lib, config, pkgs, ... }: {
-      imports = [ commonConfig ];
-      networking.nameservers = lib.mkForce [
-        nodes.dnsserver.config.networking.primaryIPAddress
-      ];
-      networking.firewall.allowedTCPPorts = [ 80 ];
-      security.acme.certs."standalone.test" = {
-        webroot = "/var/lib/acme/acme-challenges";
-      };
-      systemd.targets."acme-finished-standalone.test" = {};
-      systemd.services."acme-standalone.test" = {
-        wants = [ "acme-finished-standalone.test.target" ];
-        before = [ "acme-finished-standalone.test.target" ];
-      };
-      services.nginx.enable = true;
-      services.nginx.virtualHosts."standalone.test" = {
-        locations."/.well-known/acme-challenge".root = "/var/lib/acme/acme-challenges";
-      };
-    };
-
-    webserver = { nodes, config, pkgs, lib, ... }: {
+    # A web server which will be the node requesting certs
+    webserver = { pkgs, nodes, lib, config, ... }: {
       imports = [ commonConfig ];
+      networking.nameservers = lib.mkForce [ (dnsServerIP nodes) ];
       networking.firewall.allowedTCPPorts = [ 80 443 ];
-      networking.nameservers = lib.mkForce [
-        nodes.dnsserver.config.networking.primaryIPAddress
-      ];
-
-      # A target remains active. Use this to probe the fact that
-      # a service fired eventhough it is not RemainAfterExit
-      systemd.targets."acme-finished-a.example.test" = {};
-      systemd.services."acme-a.example.test" = {
-        wants = [ "acme-finished-a.example.test.target" ];
-        before = [ "acme-finished-a.example.test.target" ];
-        after = [ "nginx.service" ];
-      };
 
+      # OpenSSL will be used for more thorough certificate validation
+      environment.systemPackages = [ pkgs.openssl ];
+
+      # Set log level to info so that we can see when the service is reloaded
       services.nginx.enable = true;
+      services.nginx.logError = "stderr info";
 
-      services.nginx.virtualHosts."a.example.test" = {
+      # First tests configure a basic cert and run a bunch of openssl checks
+      services.nginx.virtualHosts."a.example.test" = (vhostBase pkgs) // {
         enableACME = true;
-        forceSSL = true;
-        locations."/".root = pkgs.runCommand "docroot" {} ''
-          mkdir -p "$out"
-          echo hello world > "$out/index.html"
-        '';
       };
 
-      security.acme.server = "https://acme.test/dir";
+      # Used to determine if service reload was triggered
+      systemd.targets.test-renew-nginx = {
+        wants = [ "acme-a.example.test.service" ];
+        after = [ "acme-a.example.test.service" "nginx-config-reload.service" ];
+      };
+
+      # Cert config changes will not cause the nginx configuration to change.
+      # This tests that the reload service is correctly triggered.
+      # It also tests that postRun is exec'd as root
+      specialisation.cert-change.configuration = { pkgs, ... }: {
+        security.acme.certs."a.example.test".keyType = "ec384";
+        security.acme.certs."a.example.test".postRun = ''
+          set -euo pipefail
+          touch test
+          chown root:root test
+          echo testing > test
+        '';
+      };
 
-      specialisation.second-cert.configuration = {pkgs, ...}: {
-        systemd.targets."acme-finished-b.example.test" = {};
-        systemd.services."acme-b.example.test" = {
-          wants = [ "acme-finished-b.example.test.target" ];
-          before = [ "acme-finished-b.example.test.target" ];
-          after = [ "nginx.service" ];
+      # Now adding an alias to ensure that the certs are updated
+      specialisation.nginx-aliases.configuration = { pkgs, ... }: {
+        services.nginx.virtualHosts."a.example.test" = {
+          serverAliases = [ "b.example.test" ];
         };
-        services.nginx.virtualHosts."b.example.test" = {
-          enableACME = true;
+      };
+
+      # Test using Apache HTTPD
+      specialisation.httpd-aliases.configuration = { pkgs, config, lib, ... }: {
+        services.nginx.enable = lib.mkForce false;
+        services.httpd.enable = true;
+        services.httpd.adminAddr = config.security.acme.email;
+        services.httpd.virtualHosts."c.example.test" = {
+          serverAliases = [ "d.example.test" ];
           forceSSL = true;
-          locations."/".root = pkgs.runCommand "docroot" {} ''
-            mkdir -p "$out"
-            echo hello world > "$out/index.html"
-          '';
+          enableACME = true;
+          documentRoot = documentRoot pkgs;
+        };
+
+        # Used to determine if service reload was triggered
+        systemd.targets.test-renew-httpd = {
+          wants = [ "acme-c.example.test.service" ];
+          after = [ "acme-c.example.test.service" "httpd-config-reload.service" ];
         };
       };
-      specialisation.dns-01.configuration = {pkgs, config, nodes, lib, ...}: {
+
+      # Validation via DNS-01 challenge
+      specialisation.dns-01.configuration = { pkgs, config, nodes, ... }: {
         security.acme.certs."example.test" = {
           domain = "*.example.test";
+          group = config.services.nginx.group;
           dnsProvider = "exec";
           dnsPropagationCheck = false;
-          credentialsFile = with pkgs; writeText "wildcard.env" ''
-            EXEC_PATH=${dnsScript { inherit writeScript bash curl; dnsAddress = nodes.dnsserver.config.networking.primaryIPAddress; }}
+          credentialsFile = pkgs.writeText "wildcard.env" ''
+            EXEC_PATH=${dnsScript { inherit pkgs nodes; }}
           '';
-          user = config.services.nginx.user;
-          group = config.services.nginx.group;
         };
-        systemd.targets."acme-finished-example.test" = {};
-        systemd.services."acme-example.test" = {
-          wants = [ "acme-finished-example.test.target" ];
-          before = [ "acme-finished-example.test.target" "nginx.service" ];
-          wantedBy = [ "nginx.service" ];
+
+        services.nginx.virtualHosts."dns.example.test" = (vhostBase pkgs) // {
+          useACMEHost = "example.test";
         };
-        services.nginx.virtualHosts."c.example.test" = {
+      };
+
+      # Validate service relationships by adding a slow start service to nginx' wants.
+      # Reproducer for https://github.com/NixOS/nixpkgs/issues/81842
+      specialisation.slow-startup.configuration = { pkgs, config, nodes, lib, ... }: {
+        systemd.services.my-slow-service = {
+          wantedBy = [ "multi-user.target" "nginx.service" ];
+          before = [ "nginx.service" ];
+          preStart = "sleep 5";
+          script = "${pkgs.python3}/bin/python -m http.server";
+        };
+
+        services.nginx.virtualHosts."slow.example.com" = {
           forceSSL = true;
-          sslCertificate = config.security.acme.certs."example.test".directory + "/cert.pem";
-          sslTrustedCertificate = config.security.acme.certs."example.test".directory + "/full.pem";
-          sslCertificateKey = config.security.acme.certs."example.test".directory + "/key.pem";
-          locations."/".root = pkgs.runCommand "docroot" {} ''
-            mkdir -p "$out"
-            echo hello world > "$out/index.html"
-          '';
+          enableACME = true;
+          locations."/".proxyPass = "http://localhost:8000";
         };
       };
     };
 
-    client = {nodes, lib, ...}: {
+    # The client will be used to curl the webserver to validate configuration
+    client = {nodes, lib, pkgs, ...}: {
       imports = [ commonConfig ];
-      networking.nameservers = lib.mkForce [
-        nodes.dnsserver.config.networking.primaryIPAddress
-      ];
+      networking.nameservers = lib.mkForce [ (dnsServerIP nodes) ];
+
+      # OpenSSL will be used for more thorough certificate validation
+      environment.systemPackages = [ pkgs.openssl ];
     };
   };
 
@@ -149,63 +168,168 @@ in import ./make-test-python.nix ({ lib, ... }: {
     in
     # Note, wait_for_unit does not work for oneshot services that do not have RemainAfterExit=true,
     # this is because a oneshot goes from inactive => activating => inactive, and never
-    # reaches the active state. To work around this, we create some mock target units which
-    # get pulled in by the oneshot units. The target units linger after activation, and hence we
-    # can use them to probe that a oneshot fired. It is a bit ugly, but it is the best we can do
+    # reaches the active state. Targets do not have this issue.
+
     ''
+      import time
+
+
+      has_switched = False
+
+
+      def switch_to(node, name):
+          global has_switched
+          if has_switched:
+              node.succeed(
+                  "${switchToNewServer}"
+              )
+          has_switched = True
+          node.succeed(
+              f"/run/current-system/specialisation/{name}/bin/switch-to-configuration test"
+          )
+
+
+      # Ensures the issuer of our cert matches the chain
+      # and matches the issuer we expect it to be.
+      # It's a good validation to ensure the cert.pem and fullchain.pem
+      # are not still selfsigned afer verification
+      def check_issuer(node, cert_name, issuer):
+          for fname in ("cert.pem", "fullchain.pem"):
+              actual_issuer = node.succeed(
+                  f"openssl x509 -noout -issuer -in /var/lib/acme/{cert_name}/{fname}"
+              ).partition("=")[2]
+              print(f"{fname} issuer: {actual_issuer}")
+              assert issuer.lower() in actual_issuer.lower()
+
+
+      # Ensure cert comes before chain in fullchain.pem
+      def check_fullchain(node, cert_name):
+          subject_data = node.succeed(
+              f"openssl crl2pkcs7 -nocrl -certfile /var/lib/acme/{cert_name}/fullchain.pem"
+              " | openssl pkcs7 -print_certs -noout"
+          )
+          for line in subject_data.lower().split("\n"):
+              if "subject" in line:
+                  print(f"First subject in fullchain.pem: ", line)
+                  assert cert_name.lower() in line
+                  return
+
+          assert False
+
+
+      def check_connection(node, domain, retries=3):
+          assert retries >= 0
+
+          result = node.succeed(
+              "openssl s_client -brief -verify 2 -CAfile /tmp/ca.crt"
+              f" -servername {domain} -connect {domain}:443 < /dev/null 2>&1"
+          )
+
+          for line in result.lower().split("\n"):
+              if "verification" in line and "error" in line:
+                  time.sleep(1)
+                  return check_connection(node, domain, retries - 1)
+
+
+      def check_connection_key_bits(node, domain, bits, retries=3):
+          assert retries >= 0
+
+          result = node.succeed(
+              "openssl s_client -CAfile /tmp/ca.crt"
+              f" -servername {domain} -connect {domain}:443 < /dev/null"
+              " | openssl x509 -noout -text | grep -i Public-Key"
+          )
+          print("Key type:", result)
+
+          if bits not in result:
+              time.sleep(1)
+              return check_connection_key_bits(node, domain, bits, retries - 1)
+
+
       client.start()
       dnsserver.start()
 
-      acme.wait_for_unit("default.target")
       dnsserver.wait_for_unit("pebble-challtestsrv.service")
+      client.wait_for_unit("default.target")
+
       client.succeed(
-          'curl --data \'{"host": "acme.test", "addresses": ["${nodes.acme.config.networking.primaryIPAddress}"]}\' http://${nodes.dnsserver.config.networking.primaryIPAddress}:8055/add-a'
-      )
-      client.succeed(
-          'curl --data \'{"host": "standalone.test", "addresses": ["${nodes.acmeStandalone.config.networking.primaryIPAddress}"]}\' http://${nodes.dnsserver.config.networking.primaryIPAddress}:8055/add-a'
+          'curl --data \'{"host": "acme.test", "addresses": ["${nodes.acme.config.networking.primaryIPAddress}"]}\' http://${dnsServerIP nodes}:8055/add-a'
       )
 
       acme.start()
-      acmeStandalone.start()
+      webserver.start()
 
       acme.wait_for_unit("default.target")
       acme.wait_for_unit("pebble.service")
 
-      with subtest("can request certificate with HTTPS-01 challenge"):
-          acmeStandalone.wait_for_unit("default.target")
-          acmeStandalone.succeed("systemctl start acme-standalone.test.service")
-          acmeStandalone.wait_for_unit("acme-finished-standalone.test.target")
-
-      client.wait_for_unit("default.target")
-
       client.succeed("curl https://acme.test:15000/roots/0 > /tmp/ca.crt")
       client.succeed("curl https://acme.test:15000/intermediate-keys/0 >> /tmp/ca.crt")
 
-      with subtest("Can request certificate for nginx service"):
+      with subtest("Can request certificate with HTTPS-01 challenge"):
           webserver.wait_for_unit("acme-finished-a.example.test.target")
-          client.succeed(
-              "curl --cacert /tmp/ca.crt https://a.example.test/ | grep -qF 'hello world'"
-          )
+          check_fullchain(webserver, "a.example.test")
+          check_issuer(webserver, "a.example.test", "pebble")
+          check_connection(client, "a.example.test")
 
-      with subtest("Can add another certificate for nginx service"):
-          webserver.succeed(
-              "/run/current-system/specialisation/second-cert/bin/switch-to-configuration test"
-          )
-          webserver.wait_for_unit("acme-finished-b.example.test.target")
-          client.succeed(
-              "curl --cacert /tmp/ca.crt https://b.example.test/ | grep -qF 'hello world'"
-          )
+      with subtest("Can generate valid selfsigned certs"):
+          webserver.succeed("systemctl clean acme-a.example.test.service --what=state")
+          webserver.succeed("systemctl start acme-selfsigned-a.example.test.service")
+          check_fullchain(webserver, "a.example.test")
+          check_issuer(webserver, "a.example.test", "minica")
+          # Will succeed if nginx can load the certs
+          webserver.succeed("systemctl start nginx-config-reload.service")
+
+      with subtest("Can reload nginx when timer triggers renewal"):
+          webserver.succeed("systemctl start test-renew-nginx.target")
+          check_issuer(webserver, "a.example.test", "pebble")
+          check_connection(client, "a.example.test")
+
+      with subtest("Can reload web server when cert configuration changes"):
+          switch_to(webserver, "cert-change")
+          webserver.wait_for_unit("acme-finished-a.example.test.target")
+          check_connection_key_bits(client, "a.example.test", "384")
+          webserver.succeed("grep testing /var/lib/acme/a.example.test/test")
+
+      with subtest("Can request certificate with HTTPS-01 when nginx startup is delayed"):
+          switch_to(webserver, "slow-startup")
+          webserver.wait_for_unit("acme-finished-slow.example.com.target")
+          check_issuer(webserver, "slow.example.com", "pebble")
+          check_connection(client, "slow.example.com")
+
+      with subtest("Can request certificate for vhost + aliases (nginx)"):
+          # Check the key hash before and after adding an alias. It should not change.
+          # The previous test reverts the ed384 change
+          webserver.wait_for_unit("acme-finished-a.example.test.target")
+          keyhash_old = webserver.succeed("md5sum /var/lib/acme/a.example.test/key.pem")
+          switch_to(webserver, "nginx-aliases")
+          webserver.wait_for_unit("acme-finished-a.example.test.target")
+          check_issuer(webserver, "a.example.test", "pebble")
+          check_connection(client, "a.example.test")
+          check_connection(client, "b.example.test")
+          keyhash_new = webserver.succeed("md5sum /var/lib/acme/a.example.test/key.pem")
+          assert keyhash_old == keyhash_new
+
+      with subtest("Can request certificates for vhost + aliases (apache-httpd)"):
+          switch_to(webserver, "httpd-aliases")
+          webserver.wait_for_unit("acme-finished-c.example.test.target")
+          check_issuer(webserver, "c.example.test", "pebble")
+          check_connection(client, "c.example.test")
+          check_connection(client, "d.example.test")
+
+      with subtest("Can reload httpd when timer triggers renewal"):
+          # Switch to selfsigned first
+          webserver.succeed("systemctl clean acme-c.example.test.service --what=state")
+          webserver.succeed("systemctl start acme-selfsigned-c.example.test.service")
+          check_issuer(webserver, "c.example.test", "minica")
+          webserver.succeed("systemctl start httpd-config-reload.service")
+          webserver.succeed("systemctl start test-renew-httpd.target")
+          check_issuer(webserver, "c.example.test", "pebble")
+          check_connection(client, "c.example.test")
 
       with subtest("Can request wildcard certificates using DNS-01 challenge"):
-          webserver.succeed(
-              "${switchToNewServer}"
-          )
-          webserver.succeed(
-              "/run/current-system/specialisation/dns-01/bin/switch-to-configuration test"
-          )
+          switch_to(webserver, "dns-01")
           webserver.wait_for_unit("acme-finished-example.test.target")
-          client.succeed(
-              "curl --cacert /tmp/ca.crt https://c.example.test/ | grep -qF 'hello world'"
-          )
+          check_issuer(webserver, "example.test", "pebble")
+          check_connection(client, "dns.example.test")
     '';
 })
diff --git a/nixos/tests/all-tests.nix b/nixos/tests/all-tests.nix
index bd26fc906aaa6..8048c885e15c2 100644
--- a/nixos/tests/all-tests.nix
+++ b/nixos/tests/all-tests.nix
@@ -32,7 +32,10 @@ in
   beanstalkd = handleTest ./beanstalkd.nix {};
   bees = handleTest ./bees.nix {};
   bind = handleTest ./bind.nix {};
+  bitcoind = handleTest ./bitcoind.nix {};
   bittorrent = handleTest ./bittorrent.nix {};
+  bitwarden = handleTest ./bitwarden.nix {};
+  blockbook-frontend = handleTest ./blockbook-frontend.nix {};
   buildkite-agents = handleTest ./buildkite-agents.nix {};
   boot = handleTestOn ["x86_64-linux"] ./boot.nix {}; # syslinux is unsupported on aarch64
   boot-stage1 = handleTest ./boot-stage1.nix {};
@@ -46,6 +49,7 @@ in
   ceph-multi-node = handleTestOn ["x86_64-linux"] ./ceph-multi-node.nix {};
   certmgr = handleTest ./certmgr.nix {};
   cfssl = handleTestOn ["x86_64-linux"] ./cfssl.nix {};
+  charliecloud = handleTest ./charliecloud.nix {};
   chromium = (handleTestOn ["x86_64-linux"] ./chromium.nix {}).stable or {};
   cjdns = handleTest ./cjdns.nix {};
   clickhouse = handleTest ./clickhouse.nix {};
@@ -63,10 +67,13 @@ in
   containers-macvlans = handleTest ./containers-macvlans.nix {};
   containers-physical_interfaces = handleTest ./containers-physical_interfaces.nix {};
   containers-portforward = handleTest ./containers-portforward.nix {};
+  containers-reloadable = handleTest ./containers-reloadable.nix {};
   containers-restart_networking = handleTest ./containers-restart_networking.nix {};
   containers-tmpfs = handleTest ./containers-tmpfs.nix {};
+  convos = handleTest ./convos.nix {};
   corerad = handleTest ./corerad.nix {};
   couchdb = handleTest ./couchdb.nix {};
+  cri-o = handleTestOn ["x86_64-linux"] ./cri-o.nix {};
   deluge = handleTest ./deluge.nix {};
   dhparams = handleTest ./dhparams.nix {};
   dnscrypt-proxy2 = handleTestOn ["x86_64-linux"] ./dnscrypt-proxy2.nix {};
@@ -75,15 +82,13 @@ in
   docker = handleTestOn ["x86_64-linux"] ./docker.nix {};
   oci-containers = handleTestOn ["x86_64-linux"] ./oci-containers.nix {};
   docker-edge = handleTestOn ["x86_64-linux"] ./docker-edge.nix {};
-  docker-preloader = handleTestOn ["x86_64-linux"] ./docker-preloader.nix {};
   docker-registry = handleTest ./docker-registry.nix {};
   docker-tools = handleTestOn ["x86_64-linux"] ./docker-tools.nix {};
   docker-tools-overlay = handleTestOn ["x86_64-linux"] ./docker-tools-overlay.nix {};
   documize = handleTest ./documize.nix {};
   dokuwiki = handleTest ./dokuwiki.nix {};
   dovecot = handleTest ./dovecot.nix {};
-  # ec2-config doesn't work in a sandbox as the simulated ec2 instance needs network access
-  #ec2-config = (handleTestOn ["x86_64-linux"] ./ec2.nix {}).boot-ec2-config or {};
+  ec2-config = (handleTestOn ["x86_64-linux"] ./ec2.nix {}).boot-ec2-config or {};
   ec2-nixops = (handleTestOn ["x86_64-linux"] ./ec2.nix {}).boot-ec2-nixops or {};
   ecryptfs = handleTest ./ecryptfs.nix {};
   ejabberd = handleTest ./xmpp/ejabberd.nix {};
@@ -98,6 +103,7 @@ in
   ferm = handleTest ./ferm.nix {};
   firefox = handleTest ./firefox.nix {};
   firefox-esr = handleTest ./firefox.nix { esr = true; };
+  firejail = handleTest ./firejail.nix {};
   firewall = handleTest ./firewall.nix {};
   fish = handleTest ./fish.nix {};
   flannel = handleTestOn ["x86_64-linux"] ./flannel.nix {};
@@ -124,6 +130,7 @@ in
   grafana = handleTest ./grafana.nix {};
   graphite = handleTest ./graphite.nix {};
   graylog = handleTest ./graylog.nix {};
+  grub = handleTest ./grub.nix {};
   gvisor = handleTest ./gvisor.nix {};
   hadoop.hdfs = handleTestOn [ "x86_64-linux" ] ./hadoop/hdfs.nix {};
   hadoop.yarn = handleTestOn [ "x86_64-linux" ] ./hadoop/yarn.nix {};
@@ -148,6 +155,7 @@ in
   incron = handleTest ./incron.nix {};
   influxdb = handleTest ./influxdb.nix {};
   initrd-network-ssh = handleTest ./initrd-network-ssh {};
+  initrd-network-openvpn = handleTest ./initrd-network-openvpn {};
   initrdNetwork = handleTest ./initrd-network.nix {};
   installer = handleTest ./installer.nix {};
   iodine = handleTest ./iodine.nix {};
@@ -157,6 +165,7 @@ in
   jellyfin = handleTest ./jellyfin.nix {};
   jenkins = handleTest ./jenkins.nix {};
   jirafeau = handleTest ./jirafeau.nix {};
+  jitsi-meet = handleTest ./jitsi-meet.nix {};
   k3s = handleTest ./k3s.nix {};
   kafka = handleTest ./kafka.nix {};
   keepalived = handleTest ./keepalived.nix {};
@@ -188,12 +197,10 @@ in
   mailcatcher = handleTest ./mailcatcher.nix {};
   mariadb-galera-mariabackup = handleTest ./mysql/mariadb-galera-mariabackup.nix {};
   mariadb-galera-rsync = handleTest ./mysql/mariadb-galera-rsync.nix {};
-  mathics = handleTest ./mathics.nix {};
   matomo = handleTest ./matomo.nix {};
   matrix-synapse = handleTest ./matrix-synapse.nix {};
   mediawiki = handleTest ./mediawiki.nix {};
   memcached = handleTest ./memcached.nix {};
-  mesos = handleTest ./mesos.nix {};
   metabase = handleTest ./metabase.nix {};
   miniflux = handleTest ./miniflux.nix {};
   minio = handleTest ./minio.nix {};
@@ -217,6 +224,7 @@ in
   nat.firewall = handleTest ./nat.nix { withFirewall = true; };
   nat.firewall-conntrack = handleTest ./nat.nix { withFirewall = true; withConntrackHelpers = true; };
   nat.standalone = handleTest ./nat.nix { withFirewall = false; };
+  ncdns = handleTest ./ncdns.nix {};
   ndppd = handleTest ./ndppd.nix {};
   neo4j = handleTest ./neo4j.nix {};
   specialisation = handleTest ./specialisation.nix {};
@@ -236,6 +244,7 @@ in
   nginx-pubhtml = handleTest ./nginx-pubhtml.nix {};
   nginx-sandbox = handleTestOn ["x86_64-linux"] ./nginx-sandbox.nix {};
   nginx-sso = handleTest ./nginx-sso.nix {};
+  nginx-variants = handleTest ./nginx-variants.nix {};
   nix-ssh-serve = handleTest ./nix-ssh-serve.nix {};
   nixos-generate-config = handleTest ./nixos-generate-config.nix {};
   novacomd = handleTestOn ["x86_64-linux"] ./novacomd.nix {};
@@ -260,9 +269,12 @@ in
   pgjwt = handleTest ./pgjwt.nix {};
   pgmanage = handleTest ./pgmanage.nix {};
   php = handleTest ./php {};
+  pinnwand = handleTest ./pinnwand.nix {};
   plasma5 = handleTest ./plasma5.nix {};
   plotinus = handleTest ./plotinus.nix {};
-  podman = handleTest ./podman.nix {};
+  podman = handleTestOn ["x86_64-linux"] ./podman.nix {};
+  postfix = handleTest ./postfix.nix {};
+  postfix-raise-smtpd-tls-security-level = handleTest ./postfix-raise-smtpd-tls-security-level.nix {};
   postgis = handleTest ./postgis.nix {};
   postgresql = handleTest ./postgresql.nix {};
   postgresql-wal-receiver = handleTest ./postgresql-wal-receiver.nix {};
@@ -276,6 +288,7 @@ in
   prosody = handleTest ./xmpp/prosody.nix {};
   prosodyMysql = handleTest ./xmpp/prosody-mysql.nix {};
   proxy = handleTest ./proxy.nix {};
+  pt2-clone = handleTest ./pt2-clone.nix {};
   qboot = handleTestOn ["x86_64-linux" "i686-linux"] ./qboot.nix {};
   quagga = handleTest ./quagga.nix {};
   quorum = handleTest ./quorum.nix {};
@@ -285,6 +298,7 @@ in
   redis = handleTest ./redis.nix {};
   redmine = handleTest ./redmine.nix {};
   restic = handleTest ./restic.nix {};
+  robustirc-bridge = handleTest ./robustirc-bridge.nix {};
   roundcube = handleTest ./roundcube.nix {};
   rspamd = handleTest ./rspamd.nix {};
   rss2email = handleTest ./rss2email.nix {};
@@ -295,27 +309,34 @@ in
   sanoid = handleTest ./sanoid.nix {};
   sddm = handleTest ./sddm.nix {};
   service-runner = handleTest ./service-runner.nix {};
+  shadowsocks = handleTest ./shadowsocks {};
+  shattered-pixel-dungeon = handleTest ./shattered-pixel-dungeon.nix {};
   shiori = handleTest ./shiori.nix {};
   signal-desktop = handleTest ./signal-desktop.nix {};
   simple = handleTest ./simple.nix {};
   slurm = handleTest ./slurm.nix {};
   smokeping = handleTest ./smokeping.nix {};
+  snapcast = handleTest ./snapcast.nix {};
   snapper = handleTest ./snapper.nix {};
   sogo = handleTest ./sogo.nix {};
   solr = handleTest ./solr.nix {};
   spacecookie = handleTest ./spacecookie.nix {};
   spike = handleTest ./spike.nix {};
   sonarr = handleTest ./sonarr.nix {};
+  sslh = handleTest ./sslh.nix {};
+  sssd = handleTestOn ["x86_64-linux"] ./sssd.nix {};
+  sssd-ldap = handleTestOn ["x86_64-linux"] ./sssd-ldap.nix {};
   strongswan-swanctl = handleTest ./strongswan-swanctl.nix {};
   sudo = handleTest ./sudo.nix {};
   switchTest = handleTest ./switch-test.nix {};
   sympa = handleTest ./sympa.nix {};
+  syncthing = handleTest ./syncthing.nix {};
   syncthing-init = handleTest ./syncthing-init.nix {};
   syncthing-relay = handleTest ./syncthing-relay.nix {};
   systemd = handleTest ./systemd.nix {};
   systemd-analyze = handleTest ./systemd-analyze.nix {};
   systemd-binfmt = handleTestOn ["x86_64-linux"] ./systemd-binfmt.nix {};
-  systemd-boot = handleTestOn ["x86_64-linux"] ./systemd-boot.nix {};
+  systemd-boot = handleTest ./systemd-boot.nix {};
   systemd-confinement = handleTest ./systemd-confinement.nix {};
   systemd-timesyncd = handleTest ./systemd-timesyncd.nix {};
   systemd-networkd-vrf = handleTest ./systemd-networkd-vrf.nix {};
@@ -342,9 +363,11 @@ in
   unit-php = handleTest ./web-servers/unit-php.nix {};
   upnp = handleTest ./upnp.nix {};
   uwsgi = handleTest ./uwsgi.nix {};
+  v2ray = handleTest ./v2ray.nix {};
   vault = handleTest ./vault.nix {};
   victoriametrics = handleTest ./victoriametrics.nix {};
   virtualbox = handleTestOn ["x86_64-linux"] ./virtualbox.nix {};
+  wasabibackend = handleTest ./wasabibackend.nix {};
   wireguard = handleTest ./wireguard {};
   wordpress = handleTest ./wordpress.nix {};
   xandikos = handleTest ./xandikos.nix {};
@@ -356,6 +379,7 @@ in
   yabar = handleTest ./yabar.nix {};
   yggdrasil = handleTest ./yggdrasil.nix {};
   zfs = handleTest ./zfs.nix {};
+  zigbee2mqtt = handleTest ./zigbee2mqtt.nix {};
   zoneminder = handleTest ./zoneminder.nix {};
   zookeeper = handleTest ./zookeeper.nix {};
   zsh-history = handleTest ./zsh-history.nix {};
diff --git a/nixos/tests/bcachefs.nix b/nixos/tests/bcachefs.nix
index 0541e5803225a..3f116d7df92aa 100644
--- a/nixos/tests/bcachefs.nix
+++ b/nixos/tests/bcachefs.nix
@@ -13,7 +13,7 @@ import ./make-test-python.nix ({ pkgs, ... }: {
     machine.succeed("modprobe bcachefs")
     machine.succeed("bcachefs version")
     machine.succeed("ls /dev")
-    
+
     machine.succeed(
         "mkdir /tmp/mnt",
         "udevadm settle",
diff --git a/nixos/tests/bitcoind.nix b/nixos/tests/bitcoind.nix
new file mode 100644
index 0000000000000..09f3e4a6ec078
--- /dev/null
+++ b/nixos/tests/bitcoind.nix
@@ -0,0 +1,46 @@
+import ./make-test-python.nix ({ pkgs, ... }: {
+  name = "bitcoind";
+  meta = with pkgs.stdenv.lib; {
+    maintainers = with maintainers; [ _1000101 ];
+  };
+
+  machine = { ... }: {
+    services.bitcoind."mainnet" = {
+      enable = true;
+      rpc = {
+        port = 8332;
+        users.rpc.passwordHMAC = "acc2374e5f9ba9e62a5204d3686616cf$53abdba5e67a9005be6a27ca03a93ce09e58854bc2b871523a0d239a72968033";
+        users.rpc2.passwordHMAC = "1495e4a3ad108187576c68f7f9b5ddc5$accce0881c74aa01bb8960ff3bdbd39f607fd33178147679e055a4ac35f53225";
+      };
+    };
+    services.bitcoind."testnet" = {
+      enable = true;
+      configFile = "/test.blank";
+      testnet = true;
+      rpc = {
+        port = 18332;
+      };
+      extraCmdlineOptions = [ "-rpcuser=rpc" "-rpcpassword=rpc" "-rpcauth=rpc2:1495e4a3ad108187576c68f7f9b5ddc5$accce0881c74aa01bb8960ff3bdbd39f607fd33178147679e055a4ac35f53225" ];
+    };
+  };
+
+  testScript = ''
+    start_all()
+
+    machine.wait_for_unit("bitcoind-mainnet.service")
+    machine.wait_for_unit("bitcoind-testnet.service")
+
+    machine.wait_until_succeeds(
+        'curl --user rpc:rpc --data-binary \'{"jsonrpc": "1.0", "id":"curltest", "method": "getblockchaininfo", "params": [] }\' -H \'content-type: text/plain;\' localhost:8332 |  grep \'"chain":"main"\' '
+    )
+    machine.wait_until_succeeds(
+        'curl --user rpc2:rpc2 --data-binary \'{"jsonrpc": "1.0", "id":"curltest", "method": "getblockchaininfo", "params": [] }\' -H \'content-type: text/plain;\' localhost:8332 |  grep \'"chain":"main"\' '
+    )
+    machine.wait_until_succeeds(
+        'curl --user rpc:rpc --data-binary \'{"jsonrpc": "1.0", "id":"curltest", "method": "getblockchaininfo", "params": [] }\' -H \'content-type: text/plain;\' localhost:18332 |  grep \'"chain":"test"\' '
+    )
+    machine.wait_until_succeeds(
+        'curl --user rpc2:rpc2 --data-binary \'{"jsonrpc": "1.0", "id":"curltest", "method": "getblockchaininfo", "params": [] }\' -H \'content-type: text/plain;\' localhost:18332 |  grep \'"chain":"test"\' '
+    )
+  '';
+})
diff --git a/nixos/tests/bittorrent.nix b/nixos/tests/bittorrent.nix
index 0a97d5556a269..c195b60cd5695 100644
--- a/nixos/tests/bittorrent.nix
+++ b/nixos/tests/bittorrent.nix
@@ -19,6 +19,7 @@ let
   externalClient2Address = "80.100.100.2";
   externalTrackerAddress = "80.100.100.3";
 
+  download-dir = "/var/lib/transmission/Downloads";
   transmissionConfig = { ... }: {
     environment.systemPackages = [ pkgs.transmission ];
     services.transmission = {
@@ -26,6 +27,7 @@ let
       settings = {
         dht-enabled = false;
         message-level = 3;
+        inherit download-dir;
       };
     };
   };
@@ -117,12 +119,12 @@ in
       router.wait_for_unit("miniupnpd")
 
       # Create the torrent.
-      tracker.succeed("mkdir /tmp/data")
+      tracker.succeed("mkdir ${download-dir}/data")
       tracker.succeed(
-          "cp ${file} /tmp/data/test.tar.bz2"
+          "cp ${file} ${download-dir}/data/test.tar.bz2"
       )
       tracker.succeed(
-          "transmission-create /tmp/data/test.tar.bz2 --private --tracker http://${externalTrackerAddress}:6969/announce --outfile /tmp/test.torrent"
+          "transmission-create ${download-dir}/data/test.tar.bz2 --private --tracker http://${externalTrackerAddress}:6969/announce --outfile /tmp/test.torrent"
       )
       tracker.succeed("chmod 644 /tmp/test.torrent")
 
@@ -133,18 +135,16 @@ in
 
       # Start the initial seeder.
       tracker.succeed(
-          "transmission-remote --add /tmp/test.torrent --no-portmap --no-dht --download-dir /tmp/data"
+          "transmission-remote --add /tmp/test.torrent --no-portmap --no-dht --download-dir ${download-dir}/data"
       )
 
       # Now we should be able to download from the client behind the NAT.
       tracker.wait_for_unit("httpd")
       client1.wait_for_unit("network-online.target")
+      client1.succeed("transmission-remote --add http://${externalTrackerAddress}/test.torrent >&2 &")
+      client1.wait_for_file("${download-dir}/test.tar.bz2")
       client1.succeed(
-          "transmission-remote --add http://${externalTrackerAddress}/test.torrent --download-dir /tmp >&2 &"
-      )
-      client1.wait_for_file("/tmp/test.tar.bz2")
-      client1.succeed(
-          "cmp /tmp/test.tar.bz2 ${file}"
+          "cmp ${download-dir}/test.tar.bz2 ${file}"
       )
 
       # Bring down the initial seeder.
@@ -154,11 +154,11 @@ in
       # the first client created a NAT hole in the router.
       client2.wait_for_unit("network-online.target")
       client2.succeed(
-          "transmission-remote --add http://${externalTrackerAddress}/test.torrent --no-portmap --no-dht --download-dir /tmp >&2 &"
+          "transmission-remote --add http://${externalTrackerAddress}/test.torrent --no-portmap --no-dht >&2 &"
       )
-      client2.wait_for_file("/tmp/test.tar.bz2")
+      client2.wait_for_file("${download-dir}/test.tar.bz2")
       client2.succeed(
-          "cmp /tmp/test.tar.bz2 ${file}"
+          "cmp ${download-dir}/test.tar.bz2 ${file}"
       )
     '';
 })
diff --git a/nixos/tests/bitwarden.nix b/nixos/tests/bitwarden.nix
new file mode 100644
index 0000000000000..a47c77cec2137
--- /dev/null
+++ b/nixos/tests/bitwarden.nix
@@ -0,0 +1,188 @@
+{ system ? builtins.currentSystem
+, config ? { }
+, pkgs ? import ../.. { inherit system config; }
+}:
+
+# These tests will:
+#  * Set up a bitwarden-rs server
+#  * Have Firefox use the web vault to create an account, log in, and save a password to the valut
+#  * Have the bw cli log in and read that password from the vault
+#
+# Note that Firefox must be on the same machine as the server for WebCrypto APIs to be available (or HTTPS must be configured)
+#
+# The same tests should work without modification on the official bitwarden server, if we ever package that.
+
+with import ../lib/testing-python.nix { inherit system pkgs; };
+with pkgs.lib;
+let
+  backends = [ "sqlite" "mysql" "postgresql" ];
+
+  dbPassword = "please_dont_hack";
+
+  userEmail = "meow@example.com";
+  userPassword = "also_super_secret_ZJWpBKZi668QGt"; # Must be complex to avoid interstitial warning on the signup page
+
+  storedPassword = "seeeecret";
+
+  makeBitwardenTest = backend: makeTest {
+    name = "bitwarden_rs-${backend}";
+    meta = {
+      maintainers = with pkgs.stdenv.lib.maintainers; [ jjjollyjim ];
+    };
+
+    nodes = {
+      server = { pkgs, ... }:
+        let backendConfig = {
+          mysql = {
+            services.mysql = {
+              enable = true;
+              initialScript = pkgs.writeText "mysql-init.sql" ''
+                CREATE DATABASE bitwarden;
+                CREATE USER 'bitwardenuser'@'localhost' IDENTIFIED BY '${dbPassword}';
+                GRANT ALL ON `bitwarden`.* TO 'bitwardenuser'@'localhost';
+                FLUSH PRIVILEGES;
+              '';
+              package = pkgs.mysql;
+            };
+
+            services.bitwarden_rs.config.databaseUrl = "mysql://bitwardenuser:${dbPassword}@localhost/bitwarden";
+
+            systemd.services.bitwarden_rs.after = [ "mysql.service" ];
+          };
+
+          postgresql = {
+            services.postgresql = {
+              enable = true;
+              initialScript = pkgs.writeText "postgresql-init.sql" ''
+                CREATE DATABASE bitwarden;
+                CREATE USER bitwardenuser WITH PASSWORD '${dbPassword}';
+                GRANT ALL PRIVILEGES ON DATABASE bitwarden TO bitwardenuser;
+              '';
+            };
+
+            services.bitwarden_rs.config.databaseUrl = "postgresql://bitwardenuser:${dbPassword}@localhost/bitwarden";
+
+            systemd.services.bitwarden_rs.after = [ "postgresql.service" ];
+          };
+
+          sqlite = { };
+        };
+        in
+        mkMerge [
+          backendConfig.${backend}
+          {
+            services.bitwarden_rs = {
+              enable = true;
+              dbBackend = backend;
+              config.rocketPort = 80;
+            };
+
+            networking.firewall.allowedTCPPorts = [ 80 ];
+
+            environment.systemPackages =
+              let
+                testRunner = pkgs.writers.writePython3Bin "test-runner"
+                  {
+                    libraries = [ pkgs.python3Packages.selenium ];
+                  } ''
+                  from selenium.webdriver import Firefox
+                  from selenium.webdriver.firefox.options import Options
+                  from selenium.webdriver.support.ui import WebDriverWait
+                  from selenium.webdriver.support import expected_conditions as EC
+
+                  options = Options()
+                  options.add_argument('--headless')
+                  driver = Firefox(options=options)
+
+                  driver.implicitly_wait(20)
+                  driver.get('http://localhost/#/register')
+
+                  wait = WebDriverWait(driver, 10)
+
+                  wait.until(EC.title_contains("Create Account"))
+
+                  driver.find_element_by_css_selector('input#email').send_keys(
+                    '${userEmail}'
+                  )
+                  driver.find_element_by_css_selector('input#name').send_keys(
+                    'A Cat'
+                  )
+                  driver.find_element_by_css_selector('input#masterPassword').send_keys(
+                    '${userPassword}'
+                  )
+                  driver.find_element_by_css_selector('input#masterPasswordRetype').send_keys(
+                    '${userPassword}'
+                  )
+
+                  driver.find_element_by_xpath("//button[contains(., 'Submit')]").click()
+
+                  wait.until_not(EC.title_contains("Create Account"))
+
+                  driver.find_element_by_css_selector('input#masterPassword').send_keys(
+                    '${userPassword}'
+                  )
+                  driver.find_element_by_xpath("//button[contains(., 'Log In')]").click()
+
+                  wait.until(EC.title_contains("My Vault"))
+
+                  driver.find_element_by_xpath("//button[contains(., 'Add Item')]").click()
+
+                  driver.find_element_by_css_selector('input#name').send_keys(
+                    'secrets'
+                  )
+                  driver.find_element_by_css_selector('input#loginPassword').send_keys(
+                    '${storedPassword}'
+                  )
+
+                  driver.find_element_by_xpath("//button[contains(., 'Save')]").click()
+                '';
+              in
+              [ pkgs.firefox-unwrapped pkgs.geckodriver testRunner ];
+
+            virtualisation.memorySize = 768;
+          }
+        ];
+
+      client = { pkgs, ... }:
+        {
+          environment.systemPackages = [ pkgs.bitwarden-cli ];
+        };
+    };
+
+    testScript = ''
+      start_all()
+      server.wait_for_unit("bitwarden_rs.service")
+      server.wait_for_open_port(80)
+
+      with subtest("configure the cli"):
+          client.succeed("bw --nointeraction config server http://server")
+
+      with subtest("can't login to nonexistant account"):
+          client.fail(
+              "bw --nointeraction --raw login ${userEmail} ${userPassword}"
+          )
+
+      with subtest("use the web interface to sign up, log in, and save a password"):
+          server.succeed("PYTHONUNBUFFERED=1 test-runner | systemd-cat -t test-runner")
+
+      with subtest("log in with the cli"):
+          key = client.succeed(
+              "bw --nointeraction --raw login ${userEmail} ${userPassword}"
+          ).strip()
+
+      with subtest("sync with the cli"):
+          client.succeed(f"bw --nointeraction --raw --session {key} sync -f")
+
+      with subtest("get the password with the cli"):
+          password = client.succeed(
+              f"bw --nointeraction --raw --session {key} list items | ${pkgs.jq}/bin/jq -r .[].login.password"
+          )
+          assert password.strip() == "${storedPassword}"
+    '';
+  };
+in
+builtins.listToAttrs (
+  map
+    (backend: { name = backend; value = makeBitwardenTest backend; })
+    backends
+)
diff --git a/nixos/tests/blockbook-frontend.nix b/nixos/tests/blockbook-frontend.nix
new file mode 100644
index 0000000000000..742a02999e745
--- /dev/null
+++ b/nixos/tests/blockbook-frontend.nix
@@ -0,0 +1,28 @@
+import ./make-test-python.nix ({ pkgs, ... }: {
+  name = "blockbook-frontend";
+  meta = with pkgs.stdenv.lib; {
+    maintainers = with maintainers; [ _1000101 ];
+  };
+
+  machine = { ... }: {
+    services.blockbook-frontend."test" = {
+      enable = true;
+    };
+    services.bitcoind.mainnet = {
+      enable = true;
+      rpc = {
+        port = 8030;
+        users.rpc.passwordHMAC = "acc2374e5f9ba9e62a5204d3686616cf$53abdba5e67a9005be6a27ca03a93ce09e58854bc2b871523a0d239a72968033";
+      };
+    };
+  };
+
+  testScript = ''
+    start_all()
+    machine.wait_for_unit("blockbook-frontend-test.service")
+
+    machine.wait_for_open_port(9030)
+
+    machine.succeed("curl -sSfL http://localhost:9030 | grep 'Blockbook'")
+  '';
+})
diff --git a/nixos/tests/borgbackup.nix b/nixos/tests/borgbackup.nix
index d97471e293e83..bf37eb8607b28 100644
--- a/nixos/tests/borgbackup.nix
+++ b/nixos/tests/borgbackup.nix
@@ -43,7 +43,7 @@ in {
   nodes = {
     client = { ... }: {
       services.borgbackup.jobs = {
-        
+
         local = {
           paths = dataDir;
           repo = localRepo;
diff --git a/nixos/tests/caddy.nix b/nixos/tests/caddy.nix
index 144d83179a16d..445a7fa6b0b42 100644
--- a/nixos/tests/caddy.nix
+++ b/nixos/tests/caddy.nix
@@ -1,7 +1,7 @@
 import ./make-test-python.nix ({ pkgs, ... }: {
   name = "caddy";
   meta = with pkgs.stdenv.lib.maintainers; {
-    maintainers = [ xfix ];
+    maintainers = [ xfix filalex77 ];
   };
 
   nodes = {
@@ -9,9 +9,10 @@ import ./make-test-python.nix ({ pkgs, ... }: {
       services.caddy.enable = true;
       services.caddy.config = ''
         http://localhost {
-          gzip
+          encode gzip
 
-          root ${
+          file_server
+          root * ${
             pkgs.runCommand "testdir" {} ''
               mkdir "$out"
               echo hello world > "$out/example.html"
@@ -23,9 +24,10 @@ import ./make-test-python.nix ({ pkgs, ... }: {
       specialisation.etag.configuration = {
         services.caddy.config = lib.mkForce ''
           http://localhost {
-            gzip
+            encode gzip
 
-            root ${
+            file_server
+            root * ${
               pkgs.runCommand "testdir2" {} ''
                 mkdir "$out"
                 echo changed > "$out/example.html"
@@ -59,9 +61,11 @@ import ./make-test-python.nix ({ pkgs, ... }: {
         )
         etag = etag.replace("\r\n", " ")
         http_code = webserver.succeed(
-            "curl -w \"%{{http_code}}\" -X HEAD -H 'If-None-Match: {}' {}".format(etag, url)
+            "curl --silent --show-error -o /dev/null -w \"%{{http_code}}\" --head -H 'If-None-Match: {}' {}".format(
+                etag, url
+            )
         )
-        assert int(http_code) == 304, "HTTP code is not 304"
+        assert int(http_code) == 304, "HTTP code is {}, expected 304".format(http_code)
         return etag
 
 
diff --git a/nixos/tests/ceph-multi-node.nix b/nixos/tests/ceph-multi-node.nix
index 22fe5cada4800..e26c6d5d670cf 100644
--- a/nixos/tests/ceph-multi-node.nix
+++ b/nixos/tests/ceph-multi-node.nix
@@ -183,15 +183,15 @@ let
     monA.wait_until_succeeds("ceph -s | grep 'HEALTH_OK'")
 
     monA.succeed(
-        "ceph osd pool create multi-node-test 128 128",
+        "ceph osd pool create multi-node-test 32 32",
         "ceph osd pool ls | grep 'multi-node-test'",
         "ceph osd pool rename multi-node-test multi-node-other-test",
         "ceph osd pool ls | grep 'multi-node-other-test'",
     )
-    monA.wait_until_succeeds("ceph -s | grep '1 pools, 128 pgs'")
+    monA.wait_until_succeeds("ceph -s | grep '2 pools, 33 pgs'")
     monA.succeed("ceph osd pool set multi-node-other-test size 2")
     monA.wait_until_succeeds("ceph -s | grep 'HEALTH_OK'")
-    monA.wait_until_succeeds("ceph -s | grep '128 active+clean'")
+    monA.wait_until_succeeds("ceph -s | grep '33 active+clean'")
     monA.fail(
         "ceph osd pool ls | grep 'multi-node-test'",
         "ceph osd pool delete multi-node-other-test multi-node-other-test --yes-i-really-really-mean-it",
diff --git a/nixos/tests/ceph-single-node.nix b/nixos/tests/ceph-single-node.nix
index 01c4b41384513..98528f6317bc0 100644
--- a/nixos/tests/ceph-single-node.nix
+++ b/nixos/tests/ceph-single-node.nix
@@ -143,12 +143,12 @@ let
     monA.wait_until_succeeds("ceph -s | grep 'HEALTH_OK'")
 
     monA.succeed(
-        "ceph osd pool create single-node-test 128 128",
+        "ceph osd pool create single-node-test 32 32",
         "ceph osd pool ls | grep 'single-node-test'",
         "ceph osd pool rename single-node-test single-node-other-test",
         "ceph osd pool ls | grep 'single-node-other-test'",
     )
-    monA.wait_until_succeeds("ceph -s | grep '1 pools, 128 pgs'")
+    monA.wait_until_succeeds("ceph -s | grep '2 pools, 33 pgs'")
     monA.succeed(
         "ceph osd getcrushmap -o crush",
         "crushtool -d crush -o decrushed",
@@ -158,7 +158,7 @@ let
         "ceph osd pool set single-node-other-test size 2",
     )
     monA.wait_until_succeeds("ceph -s | grep 'HEALTH_OK'")
-    monA.wait_until_succeeds("ceph -s | grep '128 active+clean'")
+    monA.wait_until_succeeds("ceph -s | grep '33 active+clean'")
     monA.fail(
         "ceph osd pool ls | grep 'multi-node-test'",
         "ceph osd pool delete single-node-other-test single-node-other-test --yes-i-really-really-mean-it",
diff --git a/nixos/tests/charliecloud.nix b/nixos/tests/charliecloud.nix
new file mode 100644
index 0000000000000..acba41e228a66
--- /dev/null
+++ b/nixos/tests/charliecloud.nix
@@ -0,0 +1,43 @@
+# This test checks charliecloud image construction and run
+
+import ./make-test-python.nix ({ pkgs, ...} : let
+
+  dockerfile = pkgs.writeText "Dockerfile" ''
+    FROM nix
+    RUN mkdir /home /tmp
+    RUN touch /etc/passwd /etc/group
+    CMD ["true"]
+  '';
+
+in {
+  name = "charliecloud";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ bzizou ];
+  };
+
+  nodes = {
+    host = { ... }: {
+      environment.systemPackages = [ pkgs.charliecloud ];
+      virtualisation.docker.enable = true;
+      users.users.alice = {
+        isNormalUser = true;
+        extraGroups = [ "docker" ];
+      };
+    };
+  };
+
+  testScript = ''
+    host.start()
+    host.wait_for_unit("docker.service")
+    host.succeed(
+        'su - alice -c "docker load --input=${pkgs.dockerTools.examples.nix}"'
+    )
+    host.succeed(
+        "cp ${dockerfile} /home/alice/Dockerfile"
+    )
+    host.succeed('su - alice -c "ch-build -t hello ."')
+    host.succeed('su - alice -c "ch-builder2tar hello /var/tmp"')
+    host.succeed('su - alice -c "ch-tar2dir /var/tmp/hello.tar.gz /var/tmp"')
+    host.succeed('su - alice -c "ch-run /var/tmp/hello -- echo Running_From_Container_OK"')
+  '';
+})
diff --git a/nixos/tests/common/acme/client/default.nix b/nixos/tests/common/acme/client/default.nix
index 80893da025244..1e9885e375c7f 100644
--- a/nixos/tests/common/acme/client/default.nix
+++ b/nixos/tests/common/acme/client/default.nix
@@ -1,15 +1,14 @@
 { lib, nodes, pkgs, ... }:
-
 let
-  acme-ca = nodes.acme.config.test-support.acme.caCert;
-in
+  caCert = nodes.acme.config.test-support.acme.caCert;
+  caDomain = nodes.acme.config.test-support.acme.caDomain;
 
-{
+in {
   security.acme = {
-    server = "https://acme.test/dir";
+    server = "https://${caDomain}/dir";
     email = "hostmaster@example.test";
     acceptTerms = true;
   };
 
-  security.pki.certificateFiles = [ acme-ca ];
+  security.pki.certificateFiles = [ caCert ];
 }
diff --git a/nixos/tests/common/acme/server/default.nix b/nixos/tests/common/acme/server/default.nix
index 1a0ee882572ce..4d8e664c4e17f 100644
--- a/nixos/tests/common/acme/server/default.nix
+++ b/nixos/tests/common/acme/server/default.nix
@@ -3,7 +3,7 @@
 #   config.test-support.acme.caCert
 #
 # This value can be used inside the configuration of other test nodes to inject
-# the snakeoil certificate into security.pki.certificateFiles or into package
+# the test certificate into security.pki.certificateFiles or into package
 # overlays.
 #
 # Another value that's needed if you don't use a custom resolver (see below for
@@ -50,19 +50,13 @@
 # Also make sure that whenever you use a resolver from a different test node
 # that it has to be started _before_ the ACME service.
 { config, pkgs, lib, ... }:
-
-
 let
-  snakeOilCerts = import ./snakeoil-certs.nix;
-
-  wfeDomain = "acme.test";
-  wfeCertFile = snakeOilCerts.${wfeDomain}.cert;
-  wfeKeyFile = snakeOilCerts.${wfeDomain}.key;
+  testCerts = import ./snakeoil-certs.nix {
+    minica = pkgs.minica;
+    mkDerivation = pkgs.stdenv.mkDerivation;
+  };
+  domain = testCerts.domain;
 
-  siteDomain = "acme.test";
-  siteCertFile = snakeOilCerts.${siteDomain}.cert;
-  siteKeyFile = snakeOilCerts.${siteDomain}.key;
-  pebble = pkgs.pebble;
   resolver = let
     message = "You need to define a resolver for the acme test module.";
     firstNS = lib.head config.networking.nameservers;
@@ -71,8 +65,9 @@ let
   pebbleConf.pebble = {
     listenAddress = "0.0.0.0:443";
     managementListenAddress = "0.0.0.0:15000";
-    certificate = snakeOilCerts.${wfeDomain}.cert;
-    privateKey = snakeOilCerts.${wfeDomain}.key;
+    # These certs and keys are used for the Web Front End (WFE)
+    certificate = testCerts.${domain}.cert;
+    privateKey = testCerts.${domain}.key;
     httpPort = 80;
     tlsPort = 443;
     ocspResponderURL = "http://0.0.0.0:4002";
@@ -80,18 +75,30 @@ let
   };
 
   pebbleConfFile = pkgs.writeText "pebble.conf" (builtins.toJSON pebbleConf);
-  pebbleDataDir = "/root/pebble";
 
 in {
   imports = [ ../../resolver.nix ];
 
-  options.test-support.acme.caCert = lib.mkOption {
-    type = lib.types.path;
-    description = ''
-      A certificate file to use with the <literal>nodes</literal> attribute to
-      inject the snakeoil CA certificate used in the ACME server into
-      <option>security.pki.certificateFiles</option>.
-    '';
+  options.test-support.acme = with lib; {
+    caDomain = mkOption {
+      type = types.str;
+      readOnly = true;
+      default = domain;
+      description = ''
+        A domain name to use with the <literal>nodes</literal> attribute to
+        identify the CA server.
+      '';
+    };
+    caCert = mkOption {
+      type = types.path;
+      readOnly = true;
+      default = testCerts.ca.cert;
+      description = ''
+        A certificate file to use with the <literal>nodes</literal> attribute to
+        inject the test CA certificate used in the ACME server into
+        <option>security.pki.certificateFiles</option>.
+      '';
+    };
   };
 
   config = {
@@ -99,35 +106,32 @@ in {
       resolver.enable = let
         isLocalResolver = config.networking.nameservers == [ "127.0.0.1" ];
       in lib.mkOverride 900 isLocalResolver;
-      acme.caCert = snakeOilCerts.ca.cert;
     };
 
     # This has priority 140, because modules/testing/test-instrumentation.nix
     # already overrides this with priority 150.
     networking.nameservers = lib.mkOverride 140 [ "127.0.0.1" ];
-    networking.firewall.enable = false;
+    networking.firewall.allowedTCPPorts = [ 80 443 15000 4002 ];
 
     networking.extraHosts = ''
-      127.0.0.1 ${wfeDomain}
-      ${config.networking.primaryIPAddress} ${wfeDomain} ${siteDomain}
+      127.0.0.1 ${domain}
+      ${config.networking.primaryIPAddress} ${domain}
     '';
 
     systemd.services = {
       pebble = {
         enable = true;
         description = "Pebble ACME server";
-        requires = [ ];
         wantedBy = [ "network.target" ];
-        preStart = ''
-          mkdir ${pebbleDataDir}
-        '';
-        script = ''
-          cd ${pebbleDataDir}
-          ${pebble}/bin/pebble -config ${pebbleConfFile}
-        '';
+
         serviceConfig = {
+          RuntimeDirectory = "pebble";
+          WorkingDirectory = "/run/pebble";
+
           # Required to bind on privileged ports.
           AmbientCapabilities = [ "CAP_NET_BIND_SERVICE" ];
+
+          ExecStart = "${pkgs.pebble}/bin/pebble -config ${pebbleConfFile}";
         };
       };
     };
diff --git a/nixos/tests/common/acme/server/mkcerts.nix b/nixos/tests/common/acme/server/mkcerts.nix
deleted file mode 100644
index 2474019cbac3b..0000000000000
--- a/nixos/tests/common/acme/server/mkcerts.nix
+++ /dev/null
@@ -1,68 +0,0 @@
-{ pkgs ? import <nixpkgs> {}
-, lib ? pkgs.lib
-, domains ? [ "acme.test" ]
-}:
-
-pkgs.runCommand "acme-snakeoil-ca" {
-  nativeBuildInputs = [ pkgs.openssl ];
-} ''
-  addpem() {
-    local file="$1"; shift
-    local storeFileName="$(IFS=.; echo "$*")"
-
-    echo -n "  " >> "$out"
-
-    # Every following argument is an attribute, so let's recurse and check
-    # every attribute whether it must be quoted and write it into $out.
-    while [ -n "$1" ]; do
-      if expr match "$1" '^[a-zA-Z][a-zA-Z0-9]*$' > /dev/null; then
-        echo -n "$1" >> "$out"
-      else
-        echo -n '"' >> "$out"
-        echo -n "$1" | sed -e 's/["$]/\\&/g' >> "$out"
-        echo -n '"' >> "$out"
-      fi
-      shift
-      [ -z "$1" ] || echo -n . >> "$out"
-    done
-
-    echo " = builtins.toFile \"$storeFileName\" '''" >> "$out"
-    sed -e 's/^/    /' "$file" >> "$out"
-
-    echo "  ''';" >> "$out"
-  }
-
-  echo '# Generated via mkcert.sh in the same directory.' > "$out"
-  echo '{' >> "$out"
-
-  openssl req -newkey rsa:4096 -x509 -sha256 -days 36500 \
-    -subj '/CN=Snakeoil CA' -nodes -out ca.pem -keyout ca.key
-
-  addpem ca.key ca key
-  addpem ca.pem ca cert
-
-  ${lib.concatMapStrings (fqdn: let
-    opensslConfig = pkgs.writeText "snakeoil.cnf" ''
-      [req]
-      default_bits = 4096
-      prompt = no
-      default_md = sha256
-      req_extensions = req_ext
-      distinguished_name = dn
-      [dn]
-      CN = ${fqdn}
-      [req_ext]
-      subjectAltName = DNS:${fqdn}
-    '';
-  in ''
-    export OPENSSL_CONF=${lib.escapeShellArg opensslConfig}
-    openssl genrsa -out snakeoil.key 4096
-    openssl req -new -key snakeoil.key -out snakeoil.csr
-    openssl x509 -req -in snakeoil.csr -sha256 -set_serial 666 \
-      -CA ca.pem -CAkey ca.key -out snakeoil.pem -days 36500
-    addpem snakeoil.key ${lib.escapeShellArg fqdn} key
-    addpem snakeoil.pem ${lib.escapeShellArg fqdn} cert
-  '') domains}
-
-  echo '}' >> "$out"
-''
diff --git a/nixos/tests/common/acme/server/mkcerts.sh b/nixos/tests/common/acme/server/mkcerts.sh
deleted file mode 100755
index cc7f8ca650dd4..0000000000000
--- a/nixos/tests/common/acme/server/mkcerts.sh
+++ /dev/null
@@ -1,6 +0,0 @@
-#!/usr/bin/env nix-shell
-#!nix-shell -p nix bash -i bash
-set -e
-cd "$(dirname "$0")"
-storepath="$(nix-build --no-out-link mkcerts.nix)"
-cat "$storepath" > snakeoil-certs.nix
diff --git a/nixos/tests/common/acme/server/snakeoil-certs.nix b/nixos/tests/common/acme/server/snakeoil-certs.nix
index fd537c3260f1d..4b6a38b8fa307 100644
--- a/nixos/tests/common/acme/server/snakeoil-certs.nix
+++ b/nixos/tests/common/acme/server/snakeoil-certs.nix
@@ -1,171 +1,37 @@
-# Generated via mkcert.sh in the same directory.
-{
-  ca.key = builtins.toFile "ca.key" ''
-    -----BEGIN PRIVATE KEY-----
-    MIIJQwIBADANBgkqhkiG9w0BAQEFAASCCS0wggkpAgEAAoICAQDCnVZGEn68ezXl
-    DWE5gjsCPqutR4nxw/wvIbAxB2Vk2WeQ6HGvt2Jdrz5qer2IXd76YtpQeqd+ffet
-    aLtMeFTr+Xy9yqEpx2AfvmEEcLnuiWbsUGZzsHwW7/4kPgAFBy9TwJn/k892lR6u
-    QYa0QS39CX85kLMZ/LZXUyClIBa+IxT1OovmGqMOr4nGASRQP6d/nnyn41Knat/d
-    tpyaa5zgfYwA6YW6UxcywvBSpMOXM0/82BFZGyALt3nQ+ffmrtKcvMjsNLBFaslV
-    +zYO1PMbLbTCW8SmJTjhzuapXtBHruvoe24133XWlvcP1ylaTx0alwiQWJr1XEOU
-    WLEFTgOTeRyiVDxDunpz+7oGcwzcdOG8nCgd6w0aYaECz1zvS3FYTQz+MiqmEkx6
-    s4bj1U90I0kwUJbeWjjrGO7Y9Qq4i19GafDg7cAMn9eHCiNbNrPj6t/gfaVbCrbk
-    m3ZVjkvLTQ2mb2lv7+tVii45227iNPuNS6lx2FVlr/DXiRrOVfghPvoOxUfXzogJ
-    hZLV4Zki+ycbGQa5w8YMDYCv4c08dKA7AatVhNS60c1zgQNjuWF3BvocSySyGUon
-    VT6h1DYlJ9YAqgqNpedgNR9kpp034SMhB7dj9leB6LRMA+c1fG/T+1lDbkA+vope
-    pt4+30oDcCTYfEifl1HwqNw/bXDm1wIDAQABAoICABPbd/UYaAQVUk93yQbUKe81
-    s9CvbvzTMYUhm9e02Hyszitz/D2gqZHDksvMkFA8u8aylXIGwdZfRglUmV/ZG1kk
-    kLzQ0xbvN/ilNUL9uYsETBMqtPly9YZloHnUNa5NqF+UVGJGk7GWz5WaLANybx3V
-    fTzDbfLl3TkVy0vt9UQbUkUfXyzwZNjXwmgIr8rcY9vasP90a3eXqRX3Tw1Wk6A4
-    TzO8oB994O0WBO150Fc6Lhwvc72yzddENlLDXq8UAXtqq9mmGqJKnhZ+1mo3AkMw
-    q7P1JyCIxcAMm26GtRvLVljXV0x5640kxDrCin6jeeW/qWkJEW6dpmuZjR5scmLI
-    /9n8H+fGzdZH8bOPPotMy12doj3vJqvew3p0eIkmVctYMJKD0j/CWjvKJNE3Yx4O
-    Ls47X/dEypX6anR1HQUXcpd6JfRWdIJANo2Duaz+HYbyA88bHcJL9shFYcjLs3sX
-    R/TvnnKHvw/ud7XBgvLGwGAf/cDEuLI2tv+V7tkMGrMUv+gUJNZaJaCpdt+1iUwO
-    QFq8APyBNn6FFw54TwXWfSjfSNh3geIMLHuErYVu9MIXvB7Yhh+ZvLcfLbmckhAX
-    wb39RRHnCWvnw5Bm9hnsDhqfDsIoP+2wvUkViyHOmrKi8nSJhSk19C8AuQtSVcJg
-    5op+epEmjt70GHt52nuBAoIBAQD2a4Ftp4QxWE2d6oAFI6WPrX7nAwI5/ezCbO/h
-    yoYAn6ucTVnn5/5ITJ8V4WTWZ4lkoZP3YSJiCyBhs8fN63J+RaJ/bFRblHDns1HA
-    2nlMVdNLg6uOfjgUJ8Y6xVM0J2dcFtwIFyK5pfZ7loxMZfvuovg74vDOi2vnO3dO
-    16DP3zUx6B/yIt57CYn8NWTq+MO2bzKUnczUQRx0yEzPOfOmVbcqGP8f7WEdDWXm
-    7scjjN53OPyKzLOVEhOMsUhIMBMO25I9ZpcVkyj3/nj+fFLf/XjOTM00M/S/KnOj
-    RwaWffx6mSYS66qNc5JSsojhIiYyiGVEWIznBpNWDU35y/uXAoIBAQDKLj0dyig2
-    kj1r3HvdgK4sRULqBQFMqE9ylxDmpJxAj6/A8hJ0RCBR57vnIIZMzK4+6K0l3VBJ
-    ukzXJHJLPkZ0Uuo2zLuRLkyjBECH6KYznyTkUVRn50Oq6IoP6WTCfd3Eg+7AKYY1
-    VFo2iR8sxeSQQ+AylFy6QcQ1xPIW30Jj1/LFjrRdRggapPEekpJec0pEqhasT8rR
-    UFhRL2NdZnL5b7ZlsJc7gZKEJgNfxgzaCzloqLcjCgGpOhLKx0fFsNOqHcbIGMwG
-    6wQCOyNghQJ6AZtRD5TYCJow92FchWjoTIaMJ8RjMKQmxpiwM6wQG4J78Hd3mbhf
-    q0hiQhPHaNbBAoIBAFeIeMFq8BpXM7sUwcURlI4lIx8Mgo33FVM7PzsFpfQyw9MR
-    5w3p6vnjvd8X4aoHvVZxzw3hA0WwjiAmrKMJL/KK6d45rP2bDUBBAplvAgeLtTLt
-    4tMLIwCF4HSgA55TIPQlaqO1FDC+M4BTSiMZVxS970/WnZPBEuNgzFDFZ+pvb4X6
-    3t40ZLNwAAQHM4IEPAFiHqWMKGZ9eo5BWIeEHnjHmfjqSDYfLJAVYk1WJIcMUzom
-    lA76CBC8CxW/I94AtcRhWuFUv/Z5/+OYEYLUxtuqPm+J+JrCmf4OJmWppT1wI2+p
-    V00BSeRVWXTm1piieM8ahF5y1hp6y3uV3k0NmKECggEBAMC42Ms3s6NpPSE+99eJ
-    3P0YPJOkl7uByNGbTKH+kW89SDRsy8iGVCSe9892gm5cwU/4LWyljO3qp2qBNG2i
-    /DfP/bCk8bqPXsAZwoWK8DrO3bTCDepJWYhlx40pVkHLBwVXGdOVAXh+YswPY2cj
-    cB9QhDrSj52AKU9z36yLvtY7uBA3Wph6tCjpx2n0H4/m6AmR9LDmEpf5tWYV/OrA
-    SKKaqUw/y7kOZyKOtbKqr/98qYmpIYFF/ZVZZSZkVXcNeoZzgdOlR37ksVqLEsrj
-    nxu7wli/uItBj/FTLjyqcvjUUYDyO1KtwBuyPUPgzYhBIN2Rt9+K6WRQelwnToFL
-    30ECggEBALzozykZj2sr3z8tQQRZuXLGotUFGsQCB8ikeqoeB8FbNNkC+qgflQGv
-    zLRB2KWOvnboc94wVgBJH43xG0HBibZnBhUO8/HBI/WlmyEj9KQ/ZskUK4GVZkB6
-    r/81ASLwH+P/rqrLEjcp1SIPPevjzCWD9VYR5m/qPHLNxStwGSrPjtPzgaFxhq84
-    Jl+YVmNqVlrOKYYfIPh8exPLiTti3wfM61pVYFv56PI2gd5ysMWYnuN+vK0sbmZh
-    cIWwykcKlODIngI7IzYqt8NuIJI0jrYyHgtUw4jaJzdF4mEOplGONxdz15jAGHtg
-    JUsBXFNz132nP4iIr3UKrPedQZijSi4=
-    -----END PRIVATE KEY-----
-  '';
-  ca.cert = builtins.toFile "ca.cert" ''
-    -----BEGIN CERTIFICATE-----
-    MIIFDzCCAvegAwIBAgIUTRDYSWJvmlhwIR3pzVrIQfnboLEwDQYJKoZIhvcNAQEL
-    BQAwFjEUMBIGA1UEAwwLU25ha2VvaWwgQ0EwIBcNMjAwMzIyMjI1NjE3WhgPMjEy
-    MDAyMjcyMjU2MTdaMBYxFDASBgNVBAMMC1NuYWtlb2lsIENBMIICIjANBgkqhkiG
-    9w0BAQEFAAOCAg8AMIICCgKCAgEAwp1WRhJ+vHs15Q1hOYI7Aj6rrUeJ8cP8LyGw
-    MQdlZNlnkOhxr7diXa8+anq9iF3e+mLaUHqnfn33rWi7THhU6/l8vcqhKcdgH75h
-    BHC57olm7FBmc7B8Fu/+JD4ABQcvU8CZ/5PPdpUerkGGtEEt/Ql/OZCzGfy2V1Mg
-    pSAWviMU9TqL5hqjDq+JxgEkUD+nf558p+NSp2rf3bacmmuc4H2MAOmFulMXMsLw
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-    /Xf/e7ZfBl8rv7vH8VXW/BC1vVsILdFncrgTrP8/4psV50/cl1F4+nPBiekvvxwZ
-    k+R7SgeSvcWT7YlOG8tm1M3al4F4mWzSRkYjkrXmwRCKAiya9xcGSt0Bob+LoM/O
-    mpDGV/PMC1WAoDc1mMuXN2hSc0n68xMcuFs+dj/nQYn8uL5pzOxpX9560ynKyLDv
-    yOzQlM2VuZ7H2hSIeYOFgrtHJJwhDtzjmUNDQpQdp9Fx+LONQTS1VLCTXND2i/3F
-    10X6PkdnLEn09RiPt5qy20pQkICxoEydmlwpFs32musYfJPdBPkZqZWrwINBv2Wb
-    HfOmEB4xUvXufZ5Ju5icgggBkyNA3PCLo0GZFRrMtvA7i9IXOcXNR+njhKa9246V
-    QQfeWiz05RmIvgShJYVsnZWtael8ni366d+UXypBYncohimyNlAD1n+Bh3z0PvBB
-    +FK4JgOSeouM4SuBHdwmlZ/H0mvfUG81Y8Jbrw0yuRHtuCtX5HpN5GKpZPHDE7aQ
-    fEShVB/GElC3n3DvgK9OJBeVVhYQgUEfJi4rsSxt3cdEI0NrdckUoZbApWVJ3CBc
-    F8Y7
-    -----END CERTIFICATE-----
-  '';
-  "acme.test".key = builtins.toFile "acme.test.key" ''
-    -----BEGIN RSA PRIVATE KEY-----
-    MIIJKAIBAAKCAgEAlgQTZjKfs3aHw0J993k7jFAs+hVRPf//zHMAiUkPKUYPTSl1
-    TxS/bPbhWzSoom00j4SLhGGGhbd+lnvTg0uvKbxskgATfw5clbm1ZN+gx4DuxwjL
-    V3xIxpeSY+PKzs5z8w/k+AJh+zOPyXwH3ut3C+ogp1S/5IhmzV3a/yU/6k0zpGxj
-    N6ZPRTXFrz93I1pPeCkJz90l7tj+2uFc9xtM20NQX52f0Y2oShcG8fKdNZVzuHHk
-    ZXkrZIhou55/nRy2jKgFeD3GQQfa9rwPWrVybQ6tKMMkoazB/Unky9xcTI2LJarf
-    xgHDO9v9yFBvmR4UM8B3kM82NHoENtHaZ2mmiMGZzTEQlf8xwYyHFrqBFIVRWEUr
-    7rr/O5Qr9gIN0T4u367HCexVYAKzbO2P9h75czzjMMoGkbXze9SMQ/ikrxEmwAHg
-    r1Xxh6iQYmgPNk8AR3d9+o2I7WJZMUYZARLnuhVr9BNXv510iqZTqX8lcyL5fEj3
-    ST4Ab+H7rfevZt6NU26iJLBYAjrA2mSvH+wvkboxrgSS8xYPkOW8NLNEbbodzofI
-    pB+SaK53OIk0bj9c1YAgrSNER/TDTgDXrWUNrlfVZ/M7+AEdeU06wi7sVhVif6OB
-    D3OpgKSNjeE6TuJH80Pi5MWugSFBr792Xb6uhVoPiVOFN+qiGB6UkwBgSKkCAwEA
-    AQKCAgAmN7OZfZwh5DiCDhZ5TXFWNba/n16rJOTN+R5R20L5iNetGLrCAs8hu2N+
-    ENRFTPzu8x14BEB5IF4niDRCZq2hPFeMemh9HfOIUV9c63vSV459NkhXaVpA/axV
-    tlqchQwVCB+U70Z28JPZCLgYmnQhnOvktTqNxhIqj5aTGbJGxpQ5d0Nvkfbv8tsB
-    4nE/mGpWel39jqFzT+Tdbjx414Ok+GkpcsacZDJTbbpfOSfD1uc8PgepskzTt8y2
-    v5JTPFVlUAjUsSgouQ+XfCGNQlx8XBjRIaXbal+hX4niRald91FTr0yC7UAHp+vn
-    dFZ586fB526OfbuZctxP+vZhEhFSseQKxHQ0tB8me81xH44daVNr9PPUM69FDT3j
-    ygJaUJjNEG3vVzePCDzhmxTmz2/rAClp77WTWziBWDoA6YWDDzhgNPrXWzLIbZIx
-    ue9ZbGEOh/u5ZzrEXxKCz9FjDe9wQu3TeYUe0M+ejzwWgn7zdWDvjjmtLUUuun2Y
-    wW7WANpu32qvB/V+qssw4O63tbRiwneRCnb8AF2ixgyWr6xyZwch4kacv1KMiixf
-    gO/5GTj7ba5GcdGoktJb29cUEgz13yPd106RsHK4vcggFxfMbOVauNRIo6ddLwyS
-    8UMxLf2i2cToOLkHZrIb8FgimmzRoBd3yYzwVJBydiVcsrHQAQKCAQEAxlzFYCiQ
-    hjEtblGnrkOC7Hx6HvqMelViOkGN8Y9VczG4GhwntmSE2nbpaAKhFBGdLfuSI3tJ
-    Lf24f0IGgAhzPmpo2TjbxPO3YSKFTH71fznVBhtQ1iSxwZ1InXktnuhot6VSDx6A
-    sbHSy1hMFy3nj+Zj5+fQ89tclzBzG9bCShaauO39KrPMwKi6CYoYdGhXBC3+OpHY
-    zBNvmDTxG2kW8L42rlf14EH4pAlgKs4eeZbpcbZ6fXURP2hToHJ8swyKw/1p12WA
-    cc19BKFJXL8nNP4uCf/fI0mVYpytz5KwUzG+z+umDqk+RRCH4mNB28xvEEuEyp/e
-    /C5Is+WrlDAA6QKCAQEAwZsK4AJ/w4Xf4Q/SsnZJO9bfP1ejJjzKElt8rG28JXeb
-    +FjykZZ6vw2gt2Boest2n9N4fBwaRkaHVtVS4iAmaDXozTlcvCLs2rVjPSguuQtW
-    80CKg6+dux+6gFN8IGzDCiX3pWUnhhiXvCcRYEcvgpH6GA5vuCNrXrjH0JFC0kef
-    aaDMGMTbzhc2IIRztmWU4v8YJSSy5KOkIQLWO+7u9aGx9IqT5/z3gx3XrItyl0Bk
-    aQmZEh7JOSyhmGhhf5LdeTLu2YgRw3/tzS+lPMX3+UPw99k9MdTOFn2pww5AdRmg
-    aBIzV+/LBYG0pPRl0D8/6yzGVBPuUDQpmK9Z3gsxwQKCAQEAnNkMZN2Ocd1+6+V7
-    LmtJog9HTSmWXMEZG7FsOJ661Yxx44txx2IyPsCaDNlPXxwSaiKrSo0Yr1oZQd8G
-    XsTPw4HGiETSWijQTulJ99PH8SLck6iTwdBgEhV5LrN75FQnQVdizHu1DUzrvkiC
-    Wi29FWb6howiCEDjNNVln5SwKn83NpVQgyyK8ag4+oQMlDdQ3wgzJ0Ld53hS3Eq4
-    f5EYR6JQgIki7YGcxrB3L0GujTxMONMuhfdEfRvUTGFawwVe0FyYDW7AIrx2Z2vV
-    I5YuvVNjOhrt6OwtSD1VnnWCITaLh8LwmlUu3NOWbudHUzKSe5MLXGEPo95BNKad
-    hl5yyQKCAQBNo0gMJtRnawMpdLfwewDJL1SdSR6S0ePS0r8/Qk4l1D5GrByyB183
-    yFY/0zhyra7nTt1NH9PlhJj3WFqBdZURSzUNP0iR5YuH9R9Twg5ihEqdB6/EOSOO
-    i521okTvl83q/ui9ecAMxUXr3NrZ+hHyUWmyRe/FLub6uCzg1a+vNauWpzXRZPgk
-    QCijh5oDdd7r3JIpKvtWNs01s7aHmDxZYjtDrmK7sDTtboUzm0QbpWXevUuV+aSF
-    +gDfZlRa3WFVHfisYSWGeYG6O7YOlfDoE7fJHGOu3QC8Ai6Wmtt8Wgd6VHokdHO8
-    xJPVZnCBvyt5up3Zz5hMr25S3VazdVfBAoIBAHVteqTGqWpKFxekGwR0RqE30wmN
-    iIEwFhgOZ8sQ+6ViZJZUR4Nn2fchn2jVwF8V8J1GrJbTknqzAwdXtO3FbgfmmyF2
-    9VbS/GgomXhA9vJkM4KK3Iwo/y/nE9hRhtzuVE0QPudz2fyfaDgnWjcNM59064tH
-    88361LVJm3ixyWSBD41UZ7NgWWJX1y2f073vErsfcPpavF5lhn1oSkQnOlgMJsnl
-    24qeuzAgTWu/2rFpIA2EK30Bgvsl3pjJxHwyNDAgklV7C783LIoAHi7VO7tzZ6iF
-    dmD5XLfcUZc3eaB7XehNQKBXDGLJeI5AFmjsHka5GUoitkU2PFrg/3+nJmg=
-    -----END RSA PRIVATE KEY-----
-  '';
-  "acme.test".cert = builtins.toFile "acme.test.cert" ''
-    -----BEGIN CERTIFICATE-----
-    MIIEoTCCAokCAgKaMA0GCSqGSIb3DQEBCwUAMBYxFDASBgNVBAMMC1NuYWtlb2ls
-    IENBMCAXDTIwMDMyMjIyNTYxOFoYDzIxMjAwMjI3MjI1NjE4WjAUMRIwEAYDVQQD
-    DAlhY21lLnRlc3QwggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIKAoICAQCWBBNm
-    Mp+zdofDQn33eTuMUCz6FVE9///McwCJSQ8pRg9NKXVPFL9s9uFbNKiibTSPhIuE
-    YYaFt36We9ODS68pvGySABN/DlyVubVk36DHgO7HCMtXfEjGl5Jj48rOznPzD+T4
-    AmH7M4/JfAfe63cL6iCnVL/kiGbNXdr/JT/qTTOkbGM3pk9FNcWvP3cjWk94KQnP
-    3SXu2P7a4Vz3G0zbQ1BfnZ/RjahKFwbx8p01lXO4ceRleStkiGi7nn+dHLaMqAV4
-    PcZBB9r2vA9atXJtDq0owyShrMH9SeTL3FxMjYslqt/GAcM72/3IUG+ZHhQzwHeQ
-    zzY0egQ20dpnaaaIwZnNMRCV/zHBjIcWuoEUhVFYRSvuuv87lCv2Ag3RPi7frscJ
-    7FVgArNs7Y/2HvlzPOMwygaRtfN71IxD+KSvESbAAeCvVfGHqJBiaA82TwBHd336
-    jYjtYlkxRhkBEue6FWv0E1e/nXSKplOpfyVzIvl8SPdJPgBv4fut969m3o1TbqIk
-    sFgCOsDaZK8f7C+RujGuBJLzFg+Q5bw0s0Rtuh3Oh8ikH5Jornc4iTRuP1zVgCCt
-    I0RH9MNOANetZQ2uV9Vn8zv4AR15TTrCLuxWFWJ/o4EPc6mApI2N4TpO4kfzQ+Lk
-    xa6BIUGvv3Zdvq6FWg+JU4U36qIYHpSTAGBIqQIDAQABMA0GCSqGSIb3DQEBCwUA
-    A4ICAQBCDs0V4z00Ze6Ask3qDOLAPo4k85QCfItlRZmwl2XbPZq7kbe13MqF2wxx
-    yiLalm6veK+ehU9MYN104hJZnuce5iEcZurk+8A+Pwn1Ifz+oWKVbUtUP3uV8Sm3
-    chktJ2H1bebXtNJE5TwvdHiUkXU9ywQt2FkxiTSl6+eac7JKEQ8lVN/o6uYxF5ds
-    +oIZplb7bv2XxsRCzq55F2tJX7fIzqXrSa+lQTnfLGmDVMAQX4TRB/lx0Gqd1a9y
-    qGfFnZ7xVyW97f6PiL8MoxPfd2I2JzrzGyP/igNbFOW0ho1OwfxVmvZeS7fQSc5e
-    +qu+nwnFfl0S4cHRif3G3zmz8Ryx9LM5TYkH41qePIHxoEO2sV0DgWJvbSjysV2S
-    EU2a31dJ0aZ+z6YtZVpHlujKMVzxVTrqj74trS4LvU5h/9hv7e1gjYdox1TO0HMK
-    mtDfgBevB21Tvxpz67Ijf31HvfTmCerKJEOjGnbYmyYpMeMNSONRDcToWk8sUwvi
-    OWa5jlUFRAxgXNM09vCTPi9aRUhcFqACqfAd6I1NqGVlfplLWrc7SWaSa+PsLfBf
-    4EOZfk8iEKBVeYXNjg+CcD8j8yk/oEs816/jpihIk8haCDRWYWGKyyGnwn6OQb8d
-    MdRO2b7Oi/AAmEF3jMlICqv286GIYK5qTKk2/CKHlOLPnsWEuA==
-    -----END CERTIFICATE-----
-  '';
+# Minica can provide a CA key and cert, plus a key
+# and cert for our fake CA server's Web Front End (WFE).
+{ minica, mkDerivation }:
+let
+  domain = "acme.test";
+
+  selfSignedCertData = mkDerivation {
+    name = "test-certs";
+    buildInputs = [ minica ];
+    phases = [ "buildPhase" "installPhase" ];
+
+    buildPhase = ''
+      mkdir ca
+      minica \
+        --ca-key ca/key.pem \
+        --ca-cert ca/cert.pem \
+        --domains ${domain}
+      chmod 600 ca/*
+      chmod 640 ${domain}/*.pem
+    '';
+
+    installPhase = ''
+      mkdir -p $out
+      mv ${domain} ca $out/
+    '';
+  };
+in {
+  inherit domain;
+  ca = {
+    cert = "${selfSignedCertData}/ca/cert.pem";
+    key = "${selfSignedCertData}/ca/key.pem";
+  };
+  "${domain}" = {
+    cert = "${selfSignedCertData}/${domain}/cert.pem";
+    key = "${selfSignedCertData}/${domain}/key.pem";
+  };
 }
diff --git a/nixos/tests/common/auto.nix b/nixos/tests/common/auto.nix
index 2c21a8d516737..da6b14e9f1608 100644
--- a/nixos/tests/common/auto.nix
+++ b/nixos/tests/common/auto.nix
@@ -41,8 +41,8 @@ in
 
   config = mkIf cfg.enable {
 
-    services.xserver.displayManager.lightdm = {
-      enable = true;
+    services.xserver.displayManager = {
+      lightdm.enable = true;
       autoLogin = {
         enable = true;
         user = cfg.user;
diff --git a/nixos/tests/common/ec2.nix b/nixos/tests/common/ec2.nix
index ba087bb600905..502fe96231f20 100644
--- a/nixos/tests/common/ec2.nix
+++ b/nixos/tests/common/ec2.nix
@@ -20,30 +20,44 @@ with pkgs.lib;
     in makeTest {
       name = "ec2-" + name;
       nodes = {};
-      testScript =
-        ''
-          my $imageDir = ($ENV{'TMPDIR'} // "/tmp") . "/vm-state-machine";
-          mkdir $imageDir, 0700;
-          my $diskImage = "$imageDir/machine.qcow2";
-          system("qemu-img create -f qcow2 -o backing_file=${image} $diskImage") == 0 or die;
-          system("qemu-img resize $diskImage 10G") == 0 or die;
+      testScript = ''
+        import os
+        import subprocess
 
-          # Note: we use net=169.0.0.0/8 rather than
-          # net=169.254.0.0/16 to prevent dhcpcd from getting horribly
-          # confused. (It would get a DHCP lease in the 169.254.*
-          # range, which it would then configure and prompty delete
-          # again when it deletes link-local addresses.) Ideally we'd
-          # turn off the DHCP server, but qemu does not have an option
-          # to do that.
-          my $startCommand = "qemu-kvm -m 1024";
-          $startCommand .= " -device virtio-net-pci,netdev=vlan0";
-          $startCommand .= " -netdev 'user,id=vlan0,net=169.0.0.0/8,guestfwd=tcp:169.254.169.254:80-cmd:${pkgs.micro-httpd}/bin/micro_httpd ${metaData}'";
-          $startCommand .= " -drive file=$diskImage,if=virtio,werror=report";
-          $startCommand .= " \$QEMU_OPTS";
+        image_dir = os.path.join(
+            os.environ.get("TMPDIR", tempfile.gettempdir()), "tmp", "vm-state-machine"
+        )
+        os.makedirs(image_dir, mode=0o700, exist_ok=True)
+        disk_image = os.path.join(image_dir, "machine.qcow2")
+        subprocess.check_call(
+            [
+                "qemu-img",
+                "create",
+                "-f",
+                "qcow2",
+                "-o",
+                "backing_file=${image}",
+                disk_image,
+            ]
+        )
+        subprocess.check_call(["qemu-img", "resize", disk_image, "10G"])
 
-          my $machine = createMachine({ startCommand => $startCommand });
+        # Note: we use net=169.0.0.0/8 rather than
+        # net=169.254.0.0/16 to prevent dhcpcd from getting horribly
+        # confused. (It would get a DHCP lease in the 169.254.*
+        # range, which it would then configure and prompty delete
+        # again when it deletes link-local addresses.) Ideally we'd
+        # turn off the DHCP server, but qemu does not have an option
+        # to do that.
+        start_command = (
+            "qemu-kvm -m 1024"
+            + " -device virtio-net-pci,netdev=vlan0"
+            + " -netdev 'user,id=vlan0,net=169.0.0.0/8,guestfwd=tcp:169.254.169.254:80-cmd:${pkgs.micro-httpd}/bin/micro_httpd ${metaData}'"
+            + f" -drive file={disk_image},if=virtio,werror=report"
+            + " $QEMU_OPTS"
+        )
 
-          ${script}
-        '';
+        machine = create_machine({"startCommand": start_command})
+      '' + script;
     };
 }
diff --git a/nixos/tests/consul.nix b/nixos/tests/consul.nix
index 6600dae4770b2..ee85f1d0b917a 100644
--- a/nixos/tests/consul.nix
+++ b/nixos/tests/consul.nix
@@ -55,30 +55,33 @@ let
 
   server = index: { pkgs, ... }:
     let
-      ip = builtins.elemAt allConsensusServerHosts index;
+      numConsensusServers = builtins.length allConsensusServerHosts;
+      thisConsensusServerHost = builtins.elemAt allConsensusServerHosts index;
+      ip = thisConsensusServerHost; # since we already use IPs to identify servers
     in
       {
         networking.interfaces.eth1.ipv4.addresses = pkgs.lib.mkOverride 0 [
-          { address = builtins.elemAt allConsensusServerHosts index; prefixLength = 16; }
+          { address = ip; prefixLength = 16; }
         ];
         networking.firewall = firewallSettings;
 
         services.consul =
-          let
-            thisConsensusServerHost = builtins.elemAt allConsensusServerHosts index;
-          in
           assert builtins.elem thisConsensusServerHost allConsensusServerHosts;
           {
             enable = true;
             inherit webUi;
             extraConfig = defaultExtraConfig // {
               server = true;
-              bootstrap_expect = builtins.length allConsensusServerHosts;
+              bootstrap_expect = numConsensusServers;
+              # Tell Consul that we never intend to drop below this many servers.
+              # Ensures to not permanently lose consensus after temporary loss.
+              # See https://github.com/hashicorp/consul/issues/8118#issuecomment-645330040
+              autopilot.min_quorum = numConsensusServers;
               retry_join =
                 # If there's only 1 node in the network, we allow self-join;
                 # otherwise, the node must not try to join itself, and join only the other servers.
                 # See https://github.com/hashicorp/consul/issues/2868
-                if builtins.length allConsensusServerHosts == 1
+                if numConsensusServers == 1
                   then allConsensusServerHosts
                   else builtins.filter (h: h != thisConsensusServerHost) allConsensusServerHosts;
               bind_addr = ip;
@@ -104,40 +107,123 @@ in {
     for m in machines:
         m.wait_for_unit("consul.service")
 
-    for m in machines:
-        m.wait_until_succeeds("[ $(consul members | grep -o alive | wc -l) == 5 ]")
+
+    def wait_for_healthy_servers():
+        # See https://github.com/hashicorp/consul/issues/8118#issuecomment-645330040
+        # for why the `Voter` column of `list-peers` has that info.
+        # TODO: The `grep true` relies on the fact that currently in
+        #       the output like
+        #           # consul operator raft list-peers
+        #           Node     ID   Address           State     Voter  RaftProtocol
+        #           server3  ...  192.168.1.3:8300  leader    true   3
+        #           server2  ...  192.168.1.2:8300  follower  true   3
+        #           server1  ...  192.168.1.1:8300  follower  false  3
+        #       `Voter`is the only boolean column.
+        #       Change this to the more reliable way to be defined by
+        #       https://github.com/hashicorp/consul/issues/8118
+        #       once that ticket is closed.
+        for m in machines:
+            m.wait_until_succeeds(
+                "[ $(consul operator raft list-peers | grep true | wc -l) == 3 ]"
+            )
+
+
+    def wait_for_all_machines_alive():
+        """
+        Note that Serf-"alive" does not mean "Raft"-healthy;
+        see `wait_for_healthy_servers()` for that instead.
+        """
+        for m in machines:
+            m.wait_until_succeeds("[ $(consul members | grep -o alive | wc -l) == 5 ]")
+
+
+    wait_for_healthy_servers()
+    # Also wait for clients to be alive.
+    wait_for_all_machines_alive()
 
     client1.succeed("consul kv put testkey 42")
     client2.succeed("[ $(consul kv get testkey) == 42 ]")
 
-    # Test that the cluster can tolearate failures of any single server:
-    for server in servers:
-        server.crash()
 
-        # For each client, wait until they have connection again
-        # using `kv get -recurse` before issuing commands.
-        client1.wait_until_succeeds("consul kv get -recurse")
-        client2.wait_until_succeeds("consul kv get -recurse")
+    def rolling_reboot_test(proper_rolling_procedure=True):
+        """
+        Tests that the cluster can tolearate failures of any single server,
+        following the recommended rolling upgrade procedure from
+        https://www.consul.io/docs/upgrading#standard-upgrades.
 
-        # Do some consul actions while one server is down.
-        client1.succeed("consul kv put testkey 43")
-        client2.succeed("[ $(consul kv get testkey) == 43 ]")
-        client2.succeed("consul kv delete testkey")
+        Optionally, `proper_rolling_procedure=False` can be given
+        to wait only for each server to be back `Healthy`, not `Stable`
+        in the Raft consensus, see Consul setting `ServerStabilizationTime` and
+        https://github.com/hashicorp/consul/issues/8118#issuecomment-645330040.
+        """
+
+        for server in servers:
+            server.crash()
+
+            # For each client, wait until they have connection again
+            # using `kv get -recurse` before issuing commands.
+            client1.wait_until_succeeds("consul kv get -recurse")
+            client2.wait_until_succeeds("consul kv get -recurse")
 
-        # Restart crashed machine.
-        server.start()
+            # Do some consul actions while one server is down.
+            client1.succeed("consul kv put testkey 43")
+            client2.succeed("[ $(consul kv get testkey) == 43 ]")
+            client2.succeed("consul kv delete testkey")
+
+            # Restart crashed machine.
+            server.start()
+
+            if proper_rolling_procedure:
+                # Wait for recovery.
+                wait_for_healthy_servers()
+            else:
+                # NOT proper rolling upgrade procedure, see above.
+                wait_for_all_machines_alive()
+
+            # Wait for client connections.
+            client1.wait_until_succeeds("consul kv get -recurse")
+            client2.wait_until_succeeds("consul kv get -recurse")
+
+            # Do some consul actions with server back up.
+            client1.succeed("consul kv put testkey 44")
+            client2.succeed("[ $(consul kv get testkey) == 44 ]")
+            client2.succeed("consul kv delete testkey")
+
+
+    def all_servers_crash_simultaneously_test():
+        """
+        Tests that the cluster will eventually come back after all
+        servers crash simultaneously.
+        """
+
+        for server in servers:
+            server.crash()
+
+        for server in servers:
+            server.start()
 
         # Wait for recovery.
-        for m in machines:
-            m.wait_until_succeeds("[ $(consul members | grep -o alive | wc -l) == 5 ]")
+        wait_for_healthy_servers()
 
         # Wait for client connections.
         client1.wait_until_succeeds("consul kv get -recurse")
         client2.wait_until_succeeds("consul kv get -recurse")
 
-        # Do some consul actions with server back up.
+        # Do some consul actions with servers back up.
         client1.succeed("consul kv put testkey 44")
         client2.succeed("[ $(consul kv get testkey) == 44 ]")
         client2.succeed("consul kv delete testkey")
+
+
+    # Run the tests.
+
+    print("rolling_reboot_test()")
+    rolling_reboot_test()
+
+    print("all_servers_crash_simultaneously_test()")
+    all_servers_crash_simultaneously_test()
+
+    print("rolling_reboot_test(proper_rolling_procedure=False)")
+    rolling_reboot_test(proper_rolling_procedure=False)
   '';
 })
diff --git a/nixos/tests/containers-portforward.nix b/nixos/tests/containers-portforward.nix
index fc90e151bd9ef..1e2c2c6c374f5 100644
--- a/nixos/tests/containers-portforward.nix
+++ b/nixos/tests/containers-portforward.nix
@@ -5,7 +5,7 @@ let
   hostPort = 10080;
   containerIp = "192.168.0.100";
   containerPort = 80;
-in 
+in
 
 import ./make-test-python.nix ({ pkgs, ...} : {
   name = "containers-portforward";
diff --git a/nixos/tests/containers-reloadable.nix b/nixos/tests/containers-reloadable.nix
index 35aff91e85b53..2d81f1639387d 100644
--- a/nixos/tests/containers-reloadable.nix
+++ b/nixos/tests/containers-reloadable.nix
@@ -9,13 +9,13 @@ let
       };
     };
 
-    # prevent make-test.nix to change IP
+    # prevent make-test-python.nix to change IP
     networking.interfaces = {
       eth1.ipv4.addresses = lib.mkOverride 0 [ ];
     };
   };
 in {
-  name = "cotnainers-reloadable";
+  name = "containers-reloadable";
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ danbst ];
   };
diff --git a/nixos/tests/convos.nix b/nixos/tests/convos.nix
new file mode 100644
index 0000000000000..b4ff1188fd8be
--- /dev/null
+++ b/nixos/tests/convos.nix
@@ -0,0 +1,30 @@
+import ./make-test-python.nix ({ lib, pkgs, ... }:
+
+with lib;
+let
+  port = 3333;
+in
+{
+  name = "convos";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ sgo ];
+  };
+
+  nodes = {
+    machine =
+      { pkgs, ... }:
+      {
+        services.convos = {
+          enable = true;
+          listenPort = port;
+        };
+      };
+  };
+
+  testScript = ''
+    machine.wait_for_unit("convos")
+    machine.wait_for_open_port("${toString port}")
+    machine.succeed("journalctl -u convos | grep -q 'Listening at.*${toString port}'")
+    machine.succeed("curl http://localhost:${toString port}/")
+  '';
+})
diff --git a/nixos/tests/corerad.nix b/nixos/tests/corerad.nix
index 72ab255b19160..37a1e90477a82 100644
--- a/nixos/tests/corerad.nix
+++ b/nixos/tests/corerad.nix
@@ -1,7 +1,7 @@
 import ./make-test-python.nix (
   {
     nodes = {
-      router = {config, pkgs, ...}: { 
+      router = {config, pkgs, ...}: {
         config = {
           # This machine simulates a router with IPv6 forwarding and a static IPv6 address.
           boot.kernel.sysctl = {
diff --git a/nixos/tests/couchdb.nix b/nixos/tests/couchdb.nix
index 10e95701acdbe..57b79e29b4330 100644
--- a/nixos/tests/couchdb.nix
+++ b/nixos/tests/couchdb.nix
@@ -1,4 +1,19 @@
-import ./make-test-python.nix ({ pkgs, lib, ...}:
+let
+
+  makeNode = couchpkg: user: passwd:
+    { pkgs, ... } :
+
+      { environment.systemPackages = with pkgs; [ jq ];
+        services.couchdb.enable = true;
+        services.couchdb.package = couchpkg;
+        services.couchdb.adminUser = user;
+        services.couchdb.adminPass = passwd;
+      };
+  testuser = "testadmin";
+  testpass = "cowabunga";
+  testlogin = "${testuser}:${testpass}@";
+
+in import ./make-test-python.nix ({ pkgs, lib, ...}:
 
 with lib;
 
@@ -9,26 +24,15 @@ with lib;
   };
 
   nodes = {
-    couchdb1 =
-      { pkgs, ... }:
-
-      { environment.systemPackages = with pkgs; [ jq ];
-        services.couchdb.enable = true;
-      };
-
-    couchdb2 =
-      { pkgs, ... }:
-
-      { environment.systemPackages = with pkgs; [ jq ];
-        services.couchdb.enable = true;
-        services.couchdb.package = pkgs.couchdb2;
-      };
+    couchdb1 = makeNode pkgs.couchdb testuser testpass;
+    couchdb2 = makeNode pkgs.couchdb2 testuser testpass;
+    couchdb3 = makeNode pkgs.couchdb3 testuser testpass;
   };
 
   testScript = let
-    curlJqCheck = action: path: jqexpr: result:
+    curlJqCheck = login: action: path: jqexpr: result:
       pkgs.writeScript "curl-jq-check-${action}-${path}.sh" ''
-        RESULT=$(curl -X ${action} http://127.0.0.1:5984/${path} | jq -r '${jqexpr}')
+        RESULT=$(curl -X ${action} http://${login}127.0.0.1:5984/${path} | jq -r '${jqexpr}')
         echo $RESULT >&2
         if [ "$RESULT" != "${result}" ]; then
           exit 1
@@ -39,38 +43,56 @@ with lib;
 
     couchdb1.wait_for_unit("couchdb.service")
     couchdb1.wait_until_succeeds(
-        "${curlJqCheck "GET" "" ".couchdb" "Welcome"}"
+        "${curlJqCheck "" "GET" "" ".couchdb" "Welcome"}"
     )
     couchdb1.wait_until_succeeds(
-        "${curlJqCheck "GET" "_all_dbs" ". | length" "2"}"
+        "${curlJqCheck "" "GET" "_all_dbs" ". | length" "2"}"
     )
-    couchdb1.succeed("${curlJqCheck "PUT" "foo" ".ok" "true"}")
+    couchdb1.succeed("${curlJqCheck testlogin "PUT" "foo" ".ok" "true"}")
     couchdb1.succeed(
-        "${curlJqCheck "GET" "_all_dbs" ". | length" "3"}"
+        "${curlJqCheck "" "GET" "_all_dbs" ". | length" "3"}"
     )
     couchdb1.succeed(
-        "${curlJqCheck "DELETE" "foo" ".ok" "true"}"
+        "${curlJqCheck testlogin "DELETE" "foo" ".ok" "true"}"
     )
     couchdb1.succeed(
-        "${curlJqCheck "GET" "_all_dbs" ". | length" "2"}"
+        "${curlJqCheck "" "GET" "_all_dbs" ". | length" "2"}"
     )
 
     couchdb2.wait_for_unit("couchdb.service")
     couchdb2.wait_until_succeeds(
-        "${curlJqCheck "GET" "" ".couchdb" "Welcome"}"
+        "${curlJqCheck "" "GET" "" ".couchdb" "Welcome"}"
     )
     couchdb2.wait_until_succeeds(
-        "${curlJqCheck "GET" "_all_dbs" ". | length" "0"}"
+        "${curlJqCheck "" "GET" "_all_dbs" ". | length" "0"}"
     )
-    couchdb2.succeed("${curlJqCheck "PUT" "foo" ".ok" "true"}")
+    couchdb2.succeed("${curlJqCheck testlogin "PUT" "foo" ".ok" "true"}")
     couchdb2.succeed(
-        "${curlJqCheck "GET" "_all_dbs" ". | length" "1"}"
+        "${curlJqCheck "" "GET" "_all_dbs" ". | length" "1"}"
     )
     couchdb2.succeed(
-        "${curlJqCheck "DELETE" "foo" ".ok" "true"}"
+        "${curlJqCheck testlogin "DELETE" "foo" ".ok" "true"}"
     )
     couchdb2.succeed(
-        "${curlJqCheck "GET" "_all_dbs" ". | length" "0"}"
+        "${curlJqCheck "" "GET" "_all_dbs" ". | length" "0"}"
+    )
+
+    couchdb3.wait_for_unit("couchdb.service")
+    couchdb3.wait_until_succeeds(
+        "${curlJqCheck testlogin "GET" "" ".couchdb" "Welcome"}"
+    )
+    couchdb3.wait_until_succeeds(
+        "${curlJqCheck testlogin "GET" "_all_dbs" ". | length" "0"}"
+    )
+    couchdb3.succeed("${curlJqCheck testlogin "PUT" "foo" ".ok" "true"}")
+    couchdb3.succeed(
+        "${curlJqCheck testlogin "GET" "_all_dbs" ". | length" "1"}"
+    )
+    couchdb3.succeed(
+        "${curlJqCheck testlogin "DELETE" "foo" ".ok" "true"}"
+    )
+    couchdb3.succeed(
+        "${curlJqCheck testlogin "GET" "_all_dbs" ". | length" "0"}"
     )
   '';
 })
diff --git a/nixos/tests/cri-o.nix b/nixos/tests/cri-o.nix
new file mode 100644
index 0000000000000..f13f1bdacb6af
--- /dev/null
+++ b/nixos/tests/cri-o.nix
@@ -0,0 +1,19 @@
+# This test runs CRI-O and verifies via critest
+import ./make-test-python.nix ({ pkgs, ... }: {
+  name = "cri-o";
+  maintainers = with pkgs.stdenv.lib.maintainers; teams.podman.members;
+
+  nodes = {
+    crio = {
+      virtualisation.cri-o.enable = true;
+    };
+  };
+
+  testScript = ''
+    start_all()
+    crio.wait_for_unit("crio.service")
+    crio.succeed(
+        "critest --ginkgo.focus='Runtime info' --runtime-endpoint unix:///var/run/crio/crio.sock"
+    )
+  '';
+})
diff --git a/nixos/tests/docker-preloader.nix b/nixos/tests/docker-preloader.nix
deleted file mode 100644
index eeedec9a392ed..0000000000000
--- a/nixos/tests/docker-preloader.nix
+++ /dev/null
@@ -1,27 +0,0 @@
-import ./make-test.nix ({ pkgs, ...} : {
-  name = "docker-preloader";
-  meta = with pkgs.stdenv.lib.maintainers; {
-    maintainers = [ lewo ];
-  };
-
-  nodes = {
-    docker =
-      { pkgs, ... }:
-        {
-          virtualisation.docker.enable = true;
-          virtualisation.dockerPreloader.images = [ pkgs.dockerTools.examples.nix pkgs.dockerTools.examples.bash ];
-
-          services.openssh.enable = true;
-          services.openssh.permitRootLogin = "yes";
-          services.openssh.extraConfig = "PermitEmptyPasswords yes";
-          users.extraUsers.root.password = "";
-        };
-  };    
-  testScript = ''
-    startAll;
-    
-    $docker->waitForUnit("sockets.target");
-    $docker->succeed("docker run nix nix-store --version");
-    $docker->succeed("docker run bash bash --version");
-  '';
-})
diff --git a/nixos/tests/docker-tools.nix b/nixos/tests/docker-tools.nix
index c48e5b0797628..edb9aec62db30 100644
--- a/nixos/tests/docker-tools.nix
+++ b/nixos/tests/docker-tools.nix
@@ -30,8 +30,45 @@ import ./make-test-python.nix ({ pkgs, ... }: {
         )
 
     docker.succeed("docker run --rm ${examples.bash.imageName} bash --version")
+    # Check imageTag attribute matches image
+    docker.succeed("docker images --format '{{.Tag}}' | grep -F '${examples.bash.imageTag}'")
     docker.succeed("docker rmi ${examples.bash.imageName}")
 
+    # The remaining combinations
+    with subtest("Ensure imageTag attribute matches image"):
+        docker.succeed(
+            "docker load --input='${examples.bashNoTag}'"
+        )
+        docker.succeed(
+            "docker images --format '{{.Tag}}' | grep -F '${examples.bashNoTag.imageTag}'"
+        )
+        docker.succeed("docker rmi ${examples.bashNoTag.imageName}:${examples.bashNoTag.imageTag}")
+
+        docker.succeed(
+            "docker load --input='${examples.bashNoTagLayered}'"
+        )
+        docker.succeed(
+            "docker images --format '{{.Tag}}' | grep -F '${examples.bashNoTagLayered.imageTag}'"
+        )
+        docker.succeed("docker rmi ${examples.bashNoTagLayered.imageName}:${examples.bashNoTagLayered.imageTag}")
+
+        docker.succeed(
+            "${examples.bashNoTagStreamLayered} | docker load"
+        )
+        docker.succeed(
+            "docker images --format '{{.Tag}}' | grep -F '${examples.bashNoTagStreamLayered.imageTag}'"
+        )
+        docker.succeed(
+            "docker rmi ${examples.bashNoTagStreamLayered.imageName}:${examples.bashNoTagStreamLayered.imageTag}"
+        )
+
+        docker.succeed(
+            "docker load --input='${examples.nixLayered}'"
+        )
+        docker.succeed("docker images --format '{{.Tag}}' | grep -F '${examples.nixLayered.imageTag}'")
+        docker.succeed("docker rmi ${examples.nixLayered.imageName}")
+
+
     with subtest(
         "Check if the nix store is correctly initialized by listing "
         "dependencies of the installed Nix binary"
@@ -42,6 +79,16 @@ import ./make-test-python.nix ({ pkgs, ... }: {
             "docker rmi ${examples.nix.imageName}",
         )
 
+    with subtest(
+        "Ensure (layered) nix store has correct permissions "
+        "and that the container starts when its process does not have uid 0"
+    ):
+        docker.succeed(
+            "docker load --input='${examples.bashLayeredWithUser}'",
+            "docker run -u somebody --rm ${examples.bashLayeredWithUser.imageName} ${pkgs.bash}/bin/bash -c 'test 555 == $(stat --format=%a /nix) && test 555 == $(stat --format=%a /nix/store)'",
+            "docker rmi ${examples.bashLayeredWithUser.imageName}",
+        )
+
     with subtest("The nix binary symlinks are intact"):
         docker.succeed(
             "docker load --input='${examples.nix}'",
@@ -90,13 +137,22 @@ import ./make-test-python.nix ({ pkgs, ... }: {
 
     with subtest("Ensure Docker images can use an unstable date"):
         docker.succeed(
-            "docker load --input='${examples.bash}'"
+            "docker load --input='${examples.unstableDate}'"
         )
         assert unix_time_second1 not in docker.succeed(
             "docker inspect ${examples.unstableDate.imageName} "
             + "| ${pkgs.jq}/bin/jq -r .[].Created"
         )
 
+    with subtest("Ensure Layered Docker images can use an unstable date"):
+        docker.succeed(
+            "docker load --input='${examples.unstableDateLayered}'"
+        )
+        assert unix_time_second1 not in docker.succeed(
+            "docker inspect ${examples.unstableDateLayered.imageName} "
+            + "| ${pkgs.jq}/bin/jq -r .[].Created"
+        )
+
     with subtest("Ensure Layered Docker images work"):
         docker.succeed(
             "docker load --input='${examples.layered-image}'",
@@ -163,20 +219,20 @@ import ./make-test-python.nix ({ pkgs, ... }: {
         )
 
     with subtest("Ensure correct behavior when no store is needed"):
-        # This check tests two requirements simultaneously
-        #  1. buildLayeredImage can build images that don't need a store.
-        #  2. Layers of symlinks are eliminated by the customization layer.
-        #
+        # This check tests that buildLayeredImage can build images that don't need a store.
         docker.succeed(
             "docker load --input='${pkgs.dockerTools.examples.no-store-paths}'"
         )
 
-        # Busybox will not recognize argv[0] and print an error message with argv[0],
-        # but it confirms that the custom-true symlink is present.
-        docker.succeed("docker run --rm no-store-paths custom-true |& grep custom-true")
-
         # This check may be loosened to allow an *empty* store rather than *no* store.
         docker.succeed("docker run --rm no-store-paths ls /")
         docker.fail("docker run --rm no-store-paths ls /nix/store")
+
+    with subtest("Ensure buildLayeredImage does not change store path contents."):
+        docker.succeed(
+            "docker load --input='${pkgs.dockerTools.examples.filesInStore}'",
+            "docker run --rm file-in-store nix-store --verify --check-contents",
+            "docker run --rm file-in-store |& grep 'some data'",
+        )
   '';
 })
diff --git a/nixos/tests/docker.nix b/nixos/tests/docker.nix
index 8fda7c1395ef3..a4a61468f33dc 100644
--- a/nixos/tests/docker.nix
+++ b/nixos/tests/docker.nix
@@ -43,7 +43,7 @@ import ./make-test-python.nix ({ pkgs, ...} : {
     docker.fail("sudo -u noprivs docker ps")
     docker.succeed("docker stop sleeping")
 
-    # Must match version twice to ensure client and server versions are correct
-    docker.succeed('[ $(docker version | grep ${pkgs.docker.version} | wc -l) = "2" ]')
+    # Must match version 4 times to ensure client and server git commits and versions are correct
+    docker.succeed('[ $(docker version | grep ${pkgs.docker.version} | wc -l) = "4" ]')
   '';
 })
diff --git a/nixos/tests/dokuwiki.nix b/nixos/tests/dokuwiki.nix
index 05271919effe8..58069366ca36e 100644
--- a/nixos/tests/dokuwiki.nix
+++ b/nixos/tests/dokuwiki.nix
@@ -32,24 +32,17 @@ let
 
 in {
   name = "dokuwiki";
-  meta.maintainers = with pkgs.lib.maintainers; [ "1000101" ];
-
+  meta = with pkgs.stdenv.lib; {
+    maintainers = with maintainers; [ _1000101 ];
+  };
   machine = { ... }: {
     services.dokuwiki."site1.local" = {
       aclUse = false;
       superUser = "admin";
-      nginx = {
-        forceSSL = false;
-        enableACME = false;
-      };
     };
     services.dokuwiki."site2.local" = {
-      aclUse = true;
+      usersFile = "/var/lib/dokuwiki/site2.local/users.auth.php";
       superUser = "admin";
-      nginx = {
-        forceSSL = false;
-        enableACME = false;
-      };
       templates = [ template-bootstrap3 ];
       plugins = [ plugin-icalevents ];
     };
@@ -69,6 +62,15 @@ in {
     machine.wait_for_open_port(80)
 
     machine.succeed("curl -sSfL http://site1.local/ | grep 'DokuWiki'")
+    machine.fail("curl -sSfL 'http://site1.local/doku.php?do=login' | grep 'Login'")
+
     machine.succeed("curl -sSfL http://site2.local/ | grep 'DokuWiki'")
+    machine.succeed("curl -sSfL 'http://site2.local/doku.php?do=login' | grep 'Login'")
+
+    machine.succeed(
+        "echo 'admin:$2y$10$ijdBQMzSVV20SrKtCna8gue36vnsbVm2wItAXvdm876sshI4uwy6S:Admin:admin@example.test:user' >> /var/lib/dokuwiki/site2.local/users.auth.php",
+        "curl -sSfL -d 'u=admin&p=password' --cookie-jar cjar 'http://site2.local/doku.php?do=login'",
+        "curl -sSfL --cookie cjar --cookie-jar cjar 'http://site2.local/doku.php?do=login' | grep 'Logged in as: <bdi>Admin</bdi>'",
+    )
   '';
 })
diff --git a/nixos/tests/ec2.nix b/nixos/tests/ec2.nix
index 5a59d65e6026f..df06724801684 100644
--- a/nixos/tests/ec2.nix
+++ b/nixos/tests/ec2.nix
@@ -3,58 +3,58 @@
   pkgs ? import ../.. { inherit system config; }
 }:
 
-with import ../lib/testing.nix { inherit system pkgs; };
+with import ../lib/testing-python.nix { inherit system pkgs; };
 with pkgs.lib;
 
 with import common/ec2.nix { inherit makeTest pkgs; };
 
 let
-  imageCfg =
-    (import ../lib/eval-config.nix {
-      inherit system;
-      modules = [
-        ../maintainers/scripts/ec2/amazon-image.nix
-        ../modules/testing/test-instrumentation.nix
-        ../modules/profiles/qemu-guest.nix
-        { ec2.hvm = true;
-
-          # Hack to make the partition resizing work in QEMU.
-          boot.initrd.postDeviceCommands = mkBefore
-            ''
-              ln -s vda /dev/xvda
-              ln -s vda1 /dev/xvda1
-            '';
-
-          # Needed by nixos-rebuild due to the lack of network
-          # access. Determined by trial and error.
-          system.extraDependencies =
-            with pkgs; (
-              [
-                # Needed for a nixos-rebuild.
-                busybox
-                stdenv
-                stdenvNoCC
-                mkinitcpio-nfs-utils
-                unionfs-fuse
-                cloud-utils
-                desktop-file-utils
-                texinfo
-                libxslt.bin
-                xorg.lndir
-
-                # These are used in the configure-from-userdata tests
-                # for EC2. Httpd and valgrind are requested by the
-                # configuration.
-                apacheHttpd apacheHttpd.doc apacheHttpd.man valgrind.doc
-              ]
-            );
-        }
-      ];
-    }).config;
+  imageCfg = (import ../lib/eval-config.nix {
+    inherit system;
+    modules = [
+      ../maintainers/scripts/ec2/amazon-image.nix
+      ../modules/testing/test-instrumentation.nix
+      ../modules/profiles/qemu-guest.nix
+      {
+        ec2.hvm = true;
+
+        # Hack to make the partition resizing work in QEMU.
+        boot.initrd.postDeviceCommands = mkBefore ''
+          ln -s vda /dev/xvda
+          ln -s vda1 /dev/xvda1
+        '';
+
+        # Needed by nixos-rebuild due to the lack of network
+        # access. Determined by trial and error.
+        system.extraDependencies = with pkgs; ( [
+          # Needed for a nixos-rebuild.
+          busybox
+          cloud-utils
+          desktop-file-utils
+          libxslt.bin
+          mkinitcpio-nfs-utils
+          stdenv
+          stdenvNoCC
+          texinfo
+          unionfs-fuse
+          xorg.lndir
+
+          # These are used in the configure-from-userdata tests
+          # for EC2. Httpd and valgrind are requested by the
+          # configuration.
+          apacheHttpd
+          apacheHttpd.doc
+          apacheHttpd.man
+          valgrind.doc
+        ]);
+      }
+    ];
+  }).config;
   image = "${imageCfg.system.build.amazonImage}/${imageCfg.amazonImage.name}.vhd";
 
   sshKeys = import ./ssh-keys.nix pkgs;
   snakeOilPrivateKey = sshKeys.snakeOilPrivateKey.text;
+  snakeOilPrivateKeyFile = pkgs.writeText "private-key" snakeOilPrivateKey;
   snakeOilPublicKey = sshKeys.snakeOilPublicKey;
 
 in {
@@ -68,43 +68,47 @@ in {
       SSH_HOST_ED25519_KEY:${replaceStrings ["\n"] ["|"] snakeOilPrivateKey}
     '';
     script = ''
-      $machine->start;
-      $machine->waitForFile("/etc/ec2-metadata/user-data");
-      $machine->waitForUnit("sshd.service");
+      machine.start()
+      machine.wait_for_file("/etc/ec2-metadata/user-data")
+      machine.wait_for_unit("sshd.service")
 
-      $machine->succeed("grep unknown /etc/ec2-metadata/ami-manifest-path");
+      machine.succeed("grep unknown /etc/ec2-metadata/ami-manifest-path")
 
       # We have no keys configured on the client side yet, so this should fail
-      $machine->fail("ssh -o BatchMode=yes localhost exit");
+      machine.fail("ssh -o BatchMode=yes localhost exit")
 
       # Let's install our client private key
-      $machine->succeed("mkdir -p ~/.ssh");
+      machine.succeed("mkdir -p ~/.ssh")
 
-      $machine->succeed("echo '${snakeOilPrivateKey}' > ~/.ssh/id_ed25519");
-      $machine->succeed("chmod 600 ~/.ssh/id_ed25519");
+      machine.copy_from_host_via_shell(
+          "${snakeOilPrivateKeyFile}", "~/.ssh/id_ed25519"
+      )
+      machine.succeed("chmod 600 ~/.ssh/id_ed25519")
 
       # We haven't configured the host key yet, so this should still fail
-      $machine->fail("ssh -o BatchMode=yes localhost exit");
+      machine.fail("ssh -o BatchMode=yes localhost exit")
 
       # Add the host key; ssh should finally succeed
-      $machine->succeed("echo localhost,127.0.0.1 ${snakeOilPublicKey} > ~/.ssh/known_hosts");
-      $machine->succeed("ssh -o BatchMode=yes localhost exit");
+      machine.succeed(
+          "echo localhost,127.0.0.1 ${snakeOilPublicKey} > ~/.ssh/known_hosts"
+      )
+      machine.succeed("ssh -o BatchMode=yes localhost exit")
 
       # Test whether the root disk was resized.
-      my $blocks = $machine->succeed("stat -c %b -f /");
-      my $bsize = $machine->succeed("stat -c %S -f /");
-      my $size = $blocks * $bsize;
-      die "wrong free space $size" if $size < 9.7 * 1024 * 1024 * 1024 || $size > 10 * 1024 * 1024 * 1024;
+      blocks, block_size = map(int, machine.succeed("stat -c %b:%S -f /").split(":"))
+      GB = 1024 ** 3
+      assert 9.7 * GB <= blocks * block_size <= 10 * GB
 
       # Just to make sure resizing is idempotent.
-      $machine->shutdown;
-      $machine->start;
-      $machine->waitForFile("/etc/ec2-metadata/user-data");
+      machine.shutdown()
+      machine.start()
+      machine.wait_for_file("/etc/ec2-metadata/user-data")
     '';
   };
 
   boot-ec2-config = makeEc2Test {
     name         = "config-userdata";
+    meta.broken = true; # amazon-init wants to download from the internet while building the system
     inherit image;
     sshPublicKey = snakeOilPublicKey;
 
@@ -133,17 +137,17 @@ in {
       }
     '';
     script = ''
-      $machine->start;
+      machine.start()
 
       # amazon-init must succeed. if it fails, make the test fail
-      # immediately instead of timing out in waitForFile.
-      $machine->waitForUnit('amazon-init.service');
+      # immediately instead of timing out in wait_for_file.
+      machine.wait_for_unit("amazon-init.service")
 
-      $machine->waitForFile("/etc/testFile");
-      $machine->succeed("cat /etc/testFile | grep -q 'whoa'");
+      machine.wait_for_file("/etc/testFile")
+      assert "whoa" in machine.succeed("cat /etc/testFile")
 
-      $machine->waitForUnit("httpd.service");
-      $machine->succeed("curl http://localhost | grep Valgrind");
+      machine.wait_for_unit("httpd.service")
+      assert "Valgrind" in machine.succeed("curl http://localhost")
     '';
   };
 }
diff --git a/nixos/tests/firejail.nix b/nixos/tests/firejail.nix
new file mode 100644
index 0000000000000..a723cb01664f3
--- /dev/null
+++ b/nixos/tests/firejail.nix
@@ -0,0 +1,82 @@
+import ./make-test-python.nix ({ pkgs, ...} : {
+  name = "firejail";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ sgo ];
+  };
+
+  nodes.machine = { ... }: {
+    imports = [ ./common/user-account.nix ];
+
+    programs.firejail = {
+      enable = true;
+      wrappedBinaries = {
+        bash-jailed  = "${pkgs.bash}/bin/bash";
+      };
+    };
+
+    systemd.services.setupFirejailTest = {
+      wantedBy = [ "multi-user.target" ];
+      before = [ "multi-user.target" ];
+
+      environment = {
+        HOME = "/home/alice";
+      };
+
+      unitConfig = {
+        type = "oneshot";
+        RemainAfterExit = true;
+        user = "alice";
+      };
+
+      script = ''
+        cd $HOME
+
+        mkdir .password-store && echo s3cret > .password-store/secret
+        mkdir my-secrets && echo s3cret > my-secrets/secret
+
+        echo publ1c > public
+
+        mkdir -p .config/firejail
+        echo 'blacklist ''${HOME}/my-secrets' > .config/firejail/globals.local
+      '';
+    };
+  };
+
+  testScript = ''
+    start_all()
+    machine.wait_for_unit("multi-user.target")
+
+    # Test path acl with wrapper
+    machine.succeed("sudo -u alice bash-jailed -c 'cat ~/public' | grep -q publ1c")
+    machine.fail(
+        "sudo -u alice bash-jailed -c 'cat ~/.password-store/secret' | grep -q s3cret"
+    )
+    machine.fail("sudo -u alice bash-jailed -c 'cat ~/my-secrets/secret' | grep -q s3cret")
+
+
+    # Test path acl with firejail executable
+    machine.succeed("sudo -u alice firejail -- bash -c 'cat ~/public' | grep -q publ1c")
+    machine.fail(
+        "sudo -u alice firejail -- bash -c 'cat ~/.password-store/secret' | grep -q s3cret"
+    )
+    machine.fail(
+        "sudo -u alice firejail -- bash -c 'cat ~/my-secrets/secret' | grep -q s3cret"
+    )
+
+    # Disabling profiles
+    machine.succeed(
+        "sudo -u alice bash -c 'firejail --noprofile -- cat ~/.password-store/secret' | grep -q s3cret"
+    )
+
+    # CVE-2020-17367
+    machine.fail(
+        "sudo -u alice firejail --private-tmp id --output=/tmp/vuln1 && cat /tmp/vuln1"
+    )
+
+    # CVE-2020-17368
+    machine.fail(
+        "sudo -u alice firejail --private-tmp --output=/tmp/foo 'bash -c $(id>/tmp/vuln2;echo id)' && cat /tmp/vuln2"
+    )
+  '';
+})
+
diff --git a/nixos/tests/gnome3-xorg.nix b/nixos/tests/gnome3-xorg.nix
index b59badcd5de40..0d05c12384f32 100644
--- a/nixos/tests/gnome3-xorg.nix
+++ b/nixos/tests/gnome3-xorg.nix
@@ -12,8 +12,9 @@ import ./make-test-python.nix ({ pkgs, lib, ...} : {
 
       services.xserver.enable = true;
 
-      services.xserver.displayManager.gdm = {
-        enable = true;
+      services.xserver.displayManager = {
+        gdm.enable = true;
+        gdm.debug = true;
         autoLogin = {
           enable = true;
           user = user.name;
@@ -21,6 +22,7 @@ import ./make-test-python.nix ({ pkgs, lib, ...} : {
       };
 
       services.xserver.desktopManager.gnome3.enable = true;
+      services.xserver.desktopManager.gnome3.debug = true;
       services.xserver.displayManager.defaultSession = "gnome-xorg";
 
       virtualisation.memorySize = 1024;
diff --git a/nixos/tests/gnome3.nix b/nixos/tests/gnome3.nix
index 17e72c5f65103..7e301be49d109 100644
--- a/nixos/tests/gnome3.nix
+++ b/nixos/tests/gnome3.nix
@@ -11,8 +11,9 @@ import ./make-test-python.nix ({ pkgs, lib, ...} : {
 
       services.xserver.enable = true;
 
-      services.xserver.displayManager.gdm = {
-        enable = true;
+      services.xserver.displayManager = {
+        gdm.enable = true;
+        gdm.debug = true;
         autoLogin = {
           enable = true;
           user = "alice";
@@ -20,6 +21,14 @@ import ./make-test-python.nix ({ pkgs, lib, ...} : {
       };
 
       services.xserver.desktopManager.gnome3.enable = true;
+      services.xserver.desktopManager.gnome3.debug = true;
+
+      environment.systemPackages = [
+        (pkgs.makeAutostartItem {
+          name = "org.gnome.Terminal";
+          package = pkgs.gnome3.gnome-terminal;
+        })
+      ];
 
       virtualisation.memorySize = 1024;
     };
@@ -63,9 +72,6 @@ import ./make-test-python.nix ({ pkgs, lib, ...} : {
           )
 
       with subtest("Open Gnome Terminal"):
-          machine.succeed(
-              "${gnomeTerminalCommand}"
-          )
           # correct output should be (true, '"gnome-terminal-server"')
           machine.wait_until_succeeds(
               "${wmClass} | grep -q 'gnome-terminal-server'"
diff --git a/nixos/tests/gotify-server.nix b/nixos/tests/gotify-server.nix
index c6e00686aed98..c0b8ba43548a8 100644
--- a/nixos/tests/gotify-server.nix
+++ b/nixos/tests/gotify-server.nix
@@ -41,5 +41,10 @@ import ./make-test-python.nix ({ pkgs, lib, ...} : {
     )
 
     assert title == "Gotify"
+
+    # Ensure that the UI responds with a successfuly code and that the
+    # response is not empty
+    result = machine.succeed("curl -fsS localhost:3000")
+    assert result, "HTTP response from localhost:3000 must not be empty!"
   '';
 })
diff --git a/nixos/tests/graphite.nix b/nixos/tests/graphite.nix
index 71776a94cbd64..137be2d89c8b3 100644
--- a/nixos/tests/graphite.nix
+++ b/nixos/tests/graphite.nix
@@ -1,11 +1,6 @@
 import ./make-test-python.nix ({ pkgs, ... } :
 {
   name = "graphite";
-  meta = {
-    # Fails on dependency `python-2.7-Twisted`'s test suite
-    # complaining `ImportError: No module named zope.interface`.
-    broken = true;
-  };
   nodes = {
     one =
       { ... }: {
@@ -21,7 +16,7 @@ import ./make-test-python.nix ({ pkgs, ... } :
           api = {
             enable = true;
             port = 8082;
-            finders = [ pkgs.python3Packages.influxgraph ];
+            finders = [ ];
           };
           carbon.enableCache = true;
           seyren.enable = false;  # Implicitely requires openssl-1.0.2u which is marked insecure
@@ -41,10 +36,14 @@ import ./make-test-python.nix ({ pkgs, ... } :
     # even if they're still in preStart (which takes quite long for graphiteWeb).
     # Wait for ports to open so we're sure the services are up and listening.
     one.wait_for_open_port(8080)
+    one.wait_for_open_port(8082)
     one.wait_for_open_port(2003)
     one.succeed('echo "foo 1 `date +%s`" | nc -N localhost 2003')
     one.wait_until_succeeds(
         "curl 'http://localhost:8080/metrics/find/?query=foo&format=treejson' --silent | grep foo >&2"
     )
+    one.wait_until_succeeds(
+        "curl 'http://localhost:8082/metrics/find/?query=foo&format=treejson' --silent | grep foo >&2"
+    )
   '';
 })
diff --git a/nixos/tests/grub.nix b/nixos/tests/grub.nix
new file mode 100644
index 0000000000000..84bfc90955b54
--- /dev/null
+++ b/nixos/tests/grub.nix
@@ -0,0 +1,60 @@
+import ./make-test-python.nix ({ lib, ... }: {
+  name = "grub";
+
+  meta = with lib.maintainers; {
+    maintainers = [ rnhmjoj ];
+  };
+
+  machine = { ... }: {
+    virtualisation.useBootLoader = true;
+
+    boot.loader.timeout = null;
+    boot.loader.grub = {
+      enable = true;
+      users.alice.password = "supersecret";
+
+      # OCR is not accurate enough
+      extraConfig = "serial; terminal_output serial";
+    };
+  };
+
+  testScript = ''
+    def grub_login_as(user, password):
+        """
+        Enters user and password to log into GRUB
+        """
+        machine.wait_for_console_text("Enter username:")
+        machine.send_chars(user + "\n")
+        machine.wait_for_console_text("Enter password:")
+        machine.send_chars(password + "\n")
+
+
+    def grub_select_all_configurations():
+        """
+        Selects "All configurations" from the GRUB menu
+        to trigger a login request.
+        """
+        machine.send_monitor_command("sendkey down")
+        machine.send_monitor_command("sendkey ret")
+
+
+    machine.start()
+
+    # wait for grub screen
+    machine.wait_for_console_text("GNU GRUB")
+
+    grub_select_all_configurations()
+    with subtest("Invalid credentials are rejected"):
+        grub_login_as("wronguser", "wrongsecret")
+        machine.wait_for_console_text("error: access denied.")
+
+    grub_select_all_configurations()
+    with subtest("Valid credentials are accepted"):
+        grub_login_as("alice", "supersecret")
+        machine.send_chars("\n")  # press enter to boot
+        machine.wait_for_console_text("Linux version")
+
+    with subtest("Machine boots correctly"):
+        machine.wait_for_unit("multi-user.target")
+  '';
+})
diff --git a/nixos/tests/hardened.nix b/nixos/tests/hardened.nix
index 5ed0dfcf9ab8f..8d845de70e248 100644
--- a/nixos/tests/hardened.nix
+++ b/nixos/tests/hardened.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, latestKernel ? false, ... } : {
+import ./make-test-python.nix ({ pkgs, latestKernel ? false, ... } : {
   name = "hardened";
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ joachifm ];
@@ -47,84 +47,88 @@ import ./make-test.nix ({ pkgs, latestKernel ? false, ... } : {
       };
     in
     ''
-      $machine->waitForUnit("multi-user.target");
+      machine.wait_for_unit("multi-user.target")
+
+
+      with subtest("AppArmor profiles are loaded"):
+          machine.succeed("systemctl status apparmor.service")
 
-      subtest "apparmor-loaded", sub {
-          $machine->succeed("systemctl status apparmor.service");
-      };
 
       # AppArmor securityfs
-      subtest "apparmor-securityfs", sub {
-          $machine->succeed("mountpoint -q /sys/kernel/security");
-          $machine->succeed("cat /sys/kernel/security/apparmor/profiles");
-      };
+      with subtest("AppArmor securityfs is mounted"):
+          machine.succeed("mountpoint -q /sys/kernel/security")
+          machine.succeed("cat /sys/kernel/security/apparmor/profiles")
+
 
       # Test loading out-of-tree modules
-      subtest "extra-module-packages", sub {
-          $machine->succeed("grep -Fq wireguard /proc/modules");
-      };
+      with subtest("Out-of-tree modules can be loaded"):
+          machine.succeed("grep -Fq wireguard /proc/modules")
+
 
       # Test hidepid
-      subtest "hidepid", sub {
-          $machine->succeed("grep -Fq hidepid=2 /proc/mounts");
+      with subtest("hidepid=2 option is applied and works"):
+          machine.succeed("grep -Fq hidepid=2 /proc/mounts")
           # cannot use pgrep -u here, it segfaults when access to process info is denied
-          $machine->succeed("[ `su - sybil -c 'ps --no-headers --user root | wc -l'` = 0 ]");
-          $machine->succeed("[ `su - alice -c 'ps --no-headers --user root | wc -l'` != 0 ]");
-      };
+          machine.succeed("[ `su - sybil -c 'ps --no-headers --user root | wc -l'` = 0 ]")
+          machine.succeed("[ `su - alice -c 'ps --no-headers --user root | wc -l'` != 0 ]")
+
 
       # Test kernel module hardening
-      subtest "lock-modules", sub {
+      with subtest("No more kernel modules can be loaded"):
           # note: this better a be module we normally wouldn't load ...
-          $machine->fail("modprobe dccp");
-      };
+          machine.fail("modprobe dccp")
+
 
       # Test userns
-      subtest "userns", sub {
-          $machine->succeed("unshare --user true");
-          $machine->fail("su -l alice -c 'unshare --user true'");
-      };
+      with subtest("User namespaces are restricted"):
+          machine.succeed("unshare --user true")
+          machine.fail("su -l alice -c 'unshare --user true'")
+
 
       # Test dmesg restriction
-      subtest "dmesg", sub {
-          $machine->fail("su -l alice -c dmesg");
-      };
+      with subtest("Regular users cannot access dmesg"):
+          machine.fail("su -l alice -c dmesg")
+
 
       # Test access to kcore
-      subtest "kcore", sub {
-          $machine->fail("cat /proc/kcore");
-      };
+      with subtest("Kcore is inaccessible as root"):
+          machine.fail("cat /proc/kcore")
+
 
       # Test deferred mount
-      subtest "mount", sub {
-        $machine->fail("mountpoint -q /efi"); # was deferred
-        $machine->execute("mkdir -p /efi");
-        $machine->succeed("mount /dev/disk/by-label/EFISYS /efi");
-        $machine->succeed("mountpoint -q /efi"); # now mounted
-      };
+      with subtest("Deferred mounts work"):
+          machine.fail("mountpoint -q /efi")  # was deferred
+          machine.execute("mkdir -p /efi")
+          machine.succeed("mount /dev/disk/by-label/EFISYS /efi")
+          machine.succeed("mountpoint -q /efi")  # now mounted
+
 
       # Test Nix dæmon usage
-      subtest "nix-daemon", sub {
-        $machine->fail("su -l nobody -s /bin/sh -c 'nix ping-store'");
-        $machine->succeed("su -l alice -c 'nix ping-store'") =~ "OK";
-      };
+      with subtest("nix-daemon cannot be used by all users"):
+          machine.fail("su -l nobody -s /bin/sh -c 'nix ping-store'")
+          machine.succeed("su -l alice -c 'nix ping-store'")
+
 
       # Test kernel image protection
-      subtest "kernelimage", sub {
-        $machine->fail("systemctl hibernate");
-        $machine->fail("systemctl kexec");
-      };
+      with subtest("The kernel image is protected"):
+          machine.fail("systemctl hibernate")
+          machine.fail("systemctl kexec")
 
-      # Test hardened memory allocator
-      sub runMallocTestProg {
-          my ($progName, $errorText) = @_;
-          my $text = "fatal allocator error: " . $errorText;
-          $machine->fail("${hardened-malloc-tests}/bin/" . $progName) =~ $text;
-      };
 
-      subtest "hardenedmalloc", sub {
-        runMallocTestProg("double_free_large", "invalid free");
-        runMallocTestProg("unaligned_free_small", "invalid unaligned free");
-        runMallocTestProg("write_after_free_small", "detected write after free");
-      };
+      # Test hardened memory allocator
+      def runMallocTestProg(prog_name, error_text):
+          text = "fatal allocator error: " + error_text
+          if not text in machine.fail(
+              "${hardened-malloc-tests}/bin/"
+              + prog_name
+              + " 2>&1"
+          ):
+              raise Exception("Hardened malloc does not work for {}".format(error_text))
+
+
+      with subtest("The hardened memory allocator works"):
+          runMallocTestProg("double_free_large", "invalid free")
+          runMallocTestProg("unaligned_free_small", "invalid unaligned free")
+          runMallocTestProg("write_after_free_small", "detected write after free")
     '';
 })
diff --git a/nixos/tests/hocker-fetchdocker/default.nix b/nixos/tests/hocker-fetchdocker/default.nix
index 4f30f01e40322..978dbf310b122 100644
--- a/nixos/tests/hocker-fetchdocker/default.nix
+++ b/nixos/tests/hocker-fetchdocker/default.nix
@@ -1,15 +1,16 @@
-import ../make-test.nix ({ pkgs, ...} : {
+import ../make-test-python.nix ({ pkgs, ...} : {
   name = "test-hocker-fetchdocker";
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ ixmatus ];
+    broken = true; # tries to download from registry-1.docker.io - how did this ever work?
   };
 
   machine = import ./machine.nix;
 
   testScript = ''
-    startAll;
+    start_all()
 
-    $machine->waitForUnit("sockets.target");
-    $machine->waitUntilSucceeds("docker run registry-1.docker.io/v2/library/hello-world:latest");
+    machine.wait_for_unit("sockets.target")
+    machine.wait_until_succeeds("docker run registry-1.docker.io/v2/library/hello-world:latest")
   '';
 })
diff --git a/nixos/tests/home-assistant.nix b/nixos/tests/home-assistant.nix
index 3365e74ba8382..a93a28d877a31 100644
--- a/nixos/tests/home-assistant.nix
+++ b/nixos/tests/home-assistant.nix
@@ -2,69 +2,66 @@ import ./make-test-python.nix ({ pkgs, ... }:
 
 let
   configDir = "/var/lib/foobar";
-  apiPassword = "some_secret";
-  mqttPassword = "another_secret";
-  hassCli = "hass-cli --server http://hass:8123 --password '${apiPassword}'";
+  mqttUsername = "homeassistant";
+  mqttPassword = "secret";
 in {
   name = "home-assistant";
   meta = with pkgs.stdenv.lib; {
     maintainers = with maintainers; [ dotlambda ];
   };
 
-  nodes = {
-    hass =
-      { pkgs, ... }:
-      {
-        environment.systemPackages = with pkgs; [
-          mosquitto home-assistant-cli
-        ];
-        services.home-assistant = {
-          inherit configDir;
-          enable = true;
-          package = pkgs.home-assistant.override {
-            extraPackages = ps: with ps; [ hbmqtt ];
-          };
-          config = {
-            homeassistant = {
-              name = "Home";
-              time_zone = "UTC";
-              latitude = "0.0";
-              longitude = "0.0";
-              elevation = 0;
-              auth_providers = [
-                {
-                  type = "legacy_api_password";
-                  api_password = apiPassword;
-                }
-              ];
-            };
-            frontend = { };
-            mqtt = { # Use hbmqtt as broker
-              password = mqttPassword;
-            };
-            binary_sensor = [
-              {
-                platform = "mqtt";
-                state_topic = "home-assistant/test";
-                payload_on = "let_there_be_light";
-                payload_off = "off";
-              }
-            ];
-          };
-          lovelaceConfig = {
-            title = "My Awesome Home";
-            views = [ {
-              title = "Example";
-              cards = [ {
-                type = "markdown";
-                title = "Lovelace";
-                content = "Welcome to your **Lovelace UI**.";
-              } ];
-            } ];
-          };
-          lovelaceConfigWritable = true;
+  nodes.hass = { pkgs, ... }: {
+    environment.systemPackages = with pkgs; [ mosquitto ];
+    services.mosquitto = {
+      enable = true;
+      users = {
+        "${mqttUsername}" = {
+          acl = [ "pattern readwrite #" ];
+          password = mqttPassword;
         };
       };
+    };
+    services.home-assistant = {
+      inherit configDir;
+      enable = true;
+      config = {
+        homeassistant = {
+          name = "Home";
+          time_zone = "UTC";
+          latitude = "0.0";
+          longitude = "0.0";
+          elevation = 0;
+        };
+        frontend = {};
+        mqtt = {
+          broker = "127.0.0.1";
+          username = mqttUsername;
+          password = mqttPassword;
+        };
+        binary_sensor = [{
+          platform = "mqtt";
+          state_topic = "home-assistant/test";
+          payload_on = "let_there_be_light";
+          payload_off = "off";
+        }];
+        logger = {
+          default = "info";
+          logs."homeassistant.components.mqtt" = "debug";
+        };
+      };
+      lovelaceConfig = {
+        title = "My Awesome Home";
+        views = [{
+          title = "Example";
+          cards = [{
+            type = "markdown";
+            title = "Lovelace";
+            content = "Welcome to your **Lovelace UI**.";
+          }];
+        }];
+      };
+      lovelaceConfigWritable = true;
+    };
   };
 
   testScript = ''
@@ -77,28 +74,13 @@ in {
     with subtest("Check that Home Assistant's web interface and API can be reached"):
         hass.wait_for_open_port(8123)
         hass.succeed("curl --fail http://localhost:8123/lovelace")
-        assert "API running" in hass.succeed(
-            "curl --fail -H 'x-ha-access: ${apiPassword}' http://localhost:8123/api/"
-        )
     with subtest("Toggle a binary sensor using MQTT"):
-        assert '"state": "off"' in hass.succeed(
-            "curl http://localhost:8123/api/states/binary_sensor.mqtt_binary_sensor -H 'x-ha-access: ${apiPassword}'"
-        )
+        # wait for broker to become available
         hass.wait_until_succeeds(
-            "mosquitto_pub -V mqttv311 -t home-assistant/test -u homeassistant -P '${mqttPassword}' -m let_there_be_light"
-        )
-        assert '"state": "on"' in hass.succeed(
-            "curl http://localhost:8123/api/states/binary_sensor.mqtt_binary_sensor -H 'x-ha-access: ${apiPassword}'"
-        )
-    with subtest("Toggle a binary sensor using hass-cli"):
-        assert '"state": "on"' in hass.succeed(
-            "${hassCli} --output json state get binary_sensor.mqtt_binary_sensor"
+            "mosquitto_sub -V mqttv311 -t home-assistant/test -u ${mqttUsername} -P '${mqttPassword}' -W 1 -t '*'"
         )
         hass.succeed(
-            "${hassCli} state edit binary_sensor.mqtt_binary_sensor --json='{\"state\": \"off\"}'"
-        )
-        assert '"state": "off"' in hass.succeed(
-            "curl http://localhost:8123/api/states/binary_sensor.mqtt_binary_sensor -H 'x-ha-access: ${apiPassword}'"
+            "mosquitto_pub -V mqttv311 -t home-assistant/test -u ${mqttUsername} -P '${mqttPassword}' -m let_there_be_light"
         )
     with subtest("Print log to ease debugging"):
         output_log = hass.succeed("cat ${configDir}/home-assistant.log")
@@ -107,5 +89,9 @@ in {
 
     with subtest("Check that no errors were logged"):
         assert "ERROR" not in output_log
+
+    # example line: 2020-06-20 10:01:32 DEBUG (MainThread) [homeassistant.components.mqtt] Received message on home-assistant/test: b'let_there_be_light'
+    with subtest("Check we received the mosquitto message"):
+        assert "let_there_be_light" in output_log
   '';
 })
diff --git a/nixos/tests/hydra/common.nix b/nixos/tests/hydra/common.nix
index f612717dc9686..312c52e889a94 100644
--- a/nixos/tests/hydra/common.nix
+++ b/nixos/tests/hydra/common.nix
@@ -37,6 +37,7 @@
     };
     services.postfix.enable = true;
     nix = {
+      distributedBuilds = true;
       buildMachines = [{
         hostName = "localhost";
         systems = [ system ];
diff --git a/nixos/tests/ihatemoney.nix b/nixos/tests/ihatemoney.nix
index 7df0ea0b691fc..0451a4505808b 100644
--- a/nixos/tests/ihatemoney.nix
+++ b/nixos/tests/ihatemoney.nix
@@ -1,5 +1,11 @@
+{ system ? builtins.currentSystem,
+  config ? {},
+  pkgs ? import ../.. { inherit system config; }
+}:
+
 let
-  f = backend: import ./make-test-python.nix ({ pkgs, ... }: {
+  inherit (import ../lib/testing-python.nix { inherit system pkgs; }) makeTest;
+  f = backend: makeTest {
     name = "ihatemoney-${backend}";
     machine = { lib, ... }: {
       services.ihatemoney = {
@@ -24,9 +30,10 @@ let
     testScript = ''
       machine.wait_for_open_port(8000)
       machine.wait_for_unit("uwsgi.service")
+      machine.wait_until_succeeds("curl http://localhost:8000")
 
       assert '"yay"' in machine.succeed(
-          "curl -X POST http://localhost:8000/api/projects -d 'name=yay&id=yay&password=yay&contact_email=yay\@example.com'"
+          "curl -X POST http://localhost:8000/api/projects -d 'name=yay&id=yay&password=yay&contact_email=yay@example.com'"
       )
       owner, timestamp = machine.succeed(
           "stat --printf %U:%G___%Y /var/lib/ihatemoney/secret_key"
@@ -48,7 +55,7 @@ let
 
       assert "ihatemoney" in machine.succeed("curl http://localhost:8000")
     '';
-  });
+  };
 in {
   ihatemoney-sqlite = f "sqlite";
   ihatemoney-postgresql = f "postgresql";
diff --git a/nixos/tests/initrd-network-openvpn/default.nix b/nixos/tests/initrd-network-openvpn/default.nix
new file mode 100644
index 0000000000000..bb4c41e6d7095
--- /dev/null
+++ b/nixos/tests/initrd-network-openvpn/default.nix
@@ -0,0 +1,145 @@
+import ../make-test-python.nix ({ lib, ...}:
+
+{
+  name = "initrd-network-openvpn";
+
+  nodes =
+    let
+
+      # Inlining of the shared secret for the
+      # OpenVPN server and client
+      secretblock = ''
+        secret [inline]
+        <secret>
+        ${lib.readFile ./shared.key}
+        </secret>
+        '';
+
+    in
+    {
+
+      # Minimal test case to check a successful boot, even with invalid config
+      minimalboot =
+        { ... }:
+        {
+          boot.initrd.network = {
+            enable = true;
+            openvpn = {
+              enable = true;
+              configuration = "/dev/null";
+            };
+          };
+        };
+
+      # initrd VPN client
+      ovpnclient =
+        { ... }:
+        {
+          virtualisation.useBootLoader = true;
+          virtualisation.vlans = [ 1 ];
+
+          boot.initrd = {
+            # This command does not fork to keep the VM in the state where
+            # only the initramfs is loaded
+            preLVMCommands =
+            ''
+              /bin/nc -p 1234 -lke /bin/echo TESTVALUE
+            '';
+
+            network = {
+              enable = true;
+
+              # Work around udhcpc only getting a lease on eth0
+              postCommands = ''
+                /bin/ip addr add 192.168.1.2/24 dev eth1
+              '';
+
+              # Example configuration for OpenVPN
+              # This is the main reason for this test
+              openvpn = {
+                enable = true;
+                configuration = "${./initrd.ovpn}";
+              };
+            };
+          };
+        };
+
+      # VPN server and gateway for ovpnclient between vlan 1 and 2
+      ovpnserver =
+        { ... }:
+        {
+          virtualisation.vlans = [ 1 2 ];
+
+          # Enable NAT and forward port 12345 to port 1234
+          networking.nat = {
+            enable = true;
+            internalInterfaces = [ "tun0" ];
+            externalInterface = "eth2";
+            forwardPorts = [ { destination = "10.8.0.2:1234";
+                               sourcePort = 12345; } ];
+          };
+
+          # Trust tun0 and allow the VPN Server to be reached
+          networking.firewall = {
+            trustedInterfaces = [ "tun0" ];
+            allowedUDPPorts = [ 1194 ];
+          };
+
+          # Minimal OpenVPN server configuration
+          services.openvpn.servers.testserver =
+          {
+            config = ''
+              dev tun0
+              ifconfig 10.8.0.1 10.8.0.2
+              ${secretblock}
+            '';
+          };
+        };
+
+      # Client that resides in the "external" VLAN
+      testclient =
+        { ... }:
+        {
+          virtualisation.vlans = [ 2 ];
+        };
+  };
+
+
+  testScript =
+    ''
+      # Minimal test case, checks whether enabling (with invalid config) harms
+      # the boot process
+      with subtest("Check for successful boot with broken openvpn config"):
+          minimalboot.start()
+          # If we get to multi-user.target, we booted successfully
+          minimalboot.wait_for_unit("multi-user.target")
+          minimalboot.shutdown()
+
+      # Elaborated test case where the ovpnclient (where this module is used)
+      # can be reached by testclient only over ovpnserver.
+      # This is an indirect test for success.
+      with subtest("Check for connection from initrd VPN client, config as file"):
+          ovpnserver.start()
+          testclient.start()
+          ovpnclient.start()
+
+          # Wait until the OpenVPN Server is available
+          ovpnserver.wait_for_unit("openvpn-testserver.service")
+          ovpnserver.succeed("ping -c 1 10.8.0.1")
+
+          # Wait for the client to connect
+          ovpnserver.wait_until_succeeds("ping -c 1 10.8.0.2")
+
+          # Wait until the testclient has network
+          testclient.wait_for_unit("network.target")
+
+          # Check that ovpnclient is reachable over vlan 1
+          ovpnserver.succeed("nc -w 2 192.168.1.2 1234 | grep -q TESTVALUE")
+
+          # Check that ovpnclient is reachable over tun0
+          ovpnserver.succeed("nc -w 2 10.8.0.2 1234 | grep -q TESTVALUE")
+
+          # Check that ovpnclient is reachable from testclient over the gateway
+          testclient.succeed("nc -w 2 192.168.2.3 12345 | grep -q TESTVALUE")
+    '';
+})
diff --git a/nixos/tests/initrd-network-openvpn/initrd.ovpn b/nixos/tests/initrd-network-openvpn/initrd.ovpn
new file mode 100644
index 0000000000000..5926a48af00f4
--- /dev/null
+++ b/nixos/tests/initrd-network-openvpn/initrd.ovpn
@@ -0,0 +1,29 @@
+remote 192.168.1.3
+dev tun
+ifconfig 10.8.0.2 10.8.0.1
+# Only force VLAN 2 through the VPN
+route 192.168.2.0 255.255.255.0 10.8.0.1
+secret [inline]
+<secret>
+#
+# 2048 bit OpenVPN static key
+#
+-----BEGIN OpenVPN Static key V1-----
+553aabe853acdfe51cd6fcfea93dcbb0
+c8797deadd1187606b1ea8f2315eb5e6
+67c0d7e830f50df45686063b189d6c6b
+aab8bb3430cc78f7bb1f78628d5c3742
+0cef4f53a5acab2894905f4499f95d8e
+e69b7b6748b17016f89e19e91481a9fd
+bf8c10651f41a1d4fdf5f438925a6733
+13cec8f04701eb47b8f7ffc48bc3d7af
+65f07bce766015b87c3db4d668c655ff
+be5a69522a8e60ccb217f8521681b45d
+27c0b70bdfbfbb426c7646d80adf7482
+3ddac58b25cb1c1bb100de974478b4c6
+8b45a94261a2405e99810cb2b3abd49f
+21b3198ada87ff3c4e656a008e540a8d
+e7811584363597599cce2040a68ac00e
+f2125540e0f7f4adc37cb3f0d922eeb7
+-----END OpenVPN Static key V1-----
+</secret>
\ No newline at end of file
diff --git a/nixos/tests/initrd-network-openvpn/shared.key b/nixos/tests/initrd-network-openvpn/shared.key
new file mode 100644
index 0000000000000..248a91a3e3d5c
--- /dev/null
+++ b/nixos/tests/initrd-network-openvpn/shared.key
@@ -0,0 +1,21 @@
+#
+# 2048 bit OpenVPN static key
+#
+-----BEGIN OpenVPN Static key V1-----
+553aabe853acdfe51cd6fcfea93dcbb0
+c8797deadd1187606b1ea8f2315eb5e6
+67c0d7e830f50df45686063b189d6c6b
+aab8bb3430cc78f7bb1f78628d5c3742
+0cef4f53a5acab2894905f4499f95d8e
+e69b7b6748b17016f89e19e91481a9fd
+bf8c10651f41a1d4fdf5f438925a6733
+13cec8f04701eb47b8f7ffc48bc3d7af
+65f07bce766015b87c3db4d668c655ff
+be5a69522a8e60ccb217f8521681b45d
+27c0b70bdfbfbb426c7646d80adf7482
+3ddac58b25cb1c1bb100de974478b4c6
+8b45a94261a2405e99810cb2b3abd49f
+21b3198ada87ff3c4e656a008e540a8d
+e7811584363597599cce2040a68ac00e
+f2125540e0f7f4adc37cb3f0d922eeb7
+-----END OpenVPN Static key V1-----
diff --git a/nixos/tests/installed-tests/default.nix b/nixos/tests/installed-tests/default.nix
index b6bdfea227701..889a00d4b5686 100644
--- a/nixos/tests/installed-tests/default.nix
+++ b/nixos/tests/installed-tests/default.nix
@@ -50,6 +50,12 @@ let
 
             environment.systemPackages = with pkgs; [ gnome-desktop-testing ];
 
+            # The installed tests need to be added to the test VM’s closure.
+            # Otherwise, their dependencies might not actually be registered
+            # as valid paths in the VM’s Nix store database,
+            # and `nix-store --query` commands run as part of the tests
+            # (for example when building Flatpak runtimes) will fail.
+            environment.variables.TESTED_PACKAGE_INSTALLED_TESTS = "${tested.installedTests}/share";
           };
 
           testScript =
diff --git a/nixos/tests/installed-tests/flatpak.nix b/nixos/tests/installed-tests/flatpak.nix
index 091c993266296..8aeeaca90f614 100644
--- a/nixos/tests/installed-tests/flatpak.nix
+++ b/nixos/tests/installed-tests/flatpak.nix
@@ -5,14 +5,11 @@ makeInstalledTest {
   withX11 = true;
 
   testConfig = {
-    services.xserver.desktopManager.gnome3.enable = true; # TODO: figure out minimal environment where the tests work
-    # common/x11.nix enables the auto display manager (lightdm)
-    services.xserver.displayManager.gdm.enable = false;
-    services.gnome3.core-utilities.enable = false;
+    xdg.portal.enable = true;
     services.flatpak.enable = true;
-    environment.systemPackages = with pkgs; [ gnupg ostree python2 ];
+    environment.systemPackages = with pkgs; [ gnupg ostree python3 ];
     virtualisation.memorySize = 2047;
-    virtualisation.diskSize = 1024;
+    virtualisation.diskSize = 3072;
   };
 
   testRunnerFlags = "--timeout 3600";
diff --git a/nixos/tests/installed-tests/ibus.nix b/nixos/tests/installed-tests/ibus.nix
index af54b612b507b..a4bc2a7d7de0b 100644
--- a/nixos/tests/installed-tests/ibus.nix
+++ b/nixos/tests/installed-tests/ibus.nix
@@ -5,16 +5,12 @@ makeInstalledTest {
 
   testConfig = {
     i18n.inputMethod.enabled = "ibus";
+    systemd.user.services.ibus-daemon = {
+      serviceConfig.ExecStart = "${pkgs.ibus}/bin/ibus-daemon --xim --verbose";
+      wantedBy = [ "graphical-session.target" ];
+      partOf = [ "graphical-session.target" ];
+    };
   };
 
-  preTestScript = ''
-    # ibus has ibus-desktop-testing-runner but it tries to manage desktop session so we just spawn ibus-daemon ourselves
-    machine.succeed("ibus-daemon --daemonize --verbose")
-  '';
-
   withX11 = true;
-
-  # TODO: ibus-daemon is currently crashing or something
-  # maybe make ibus systemd service that auto-restarts?
-  meta.broken = true;
 }
diff --git a/nixos/tests/installed-tests/ostree.nix b/nixos/tests/installed-tests/ostree.nix
index eef7cace54cc1..90e09ad4ddf49 100644
--- a/nixos/tests/installed-tests/ostree.nix
+++ b/nixos/tests/installed-tests/ostree.nix
@@ -3,21 +3,10 @@
 makeInstalledTest {
   tested = pkgs.ostree;
 
-  # TODO: Wrap/patch the tests directly in the package
   testConfig = {
     environment.systemPackages = with pkgs; [
-      (python3.withPackages (p: with p; [ pyyaml ]))
       gnupg
       ostree
     ];
-
-    # for GJS tests
-    environment.variables.GI_TYPELIB_PATH = lib.makeSearchPath "lib/girepository-1.0" (with pkgs; [
-      gtk3
-      pango.out
-      ostree
-      gdk-pixbuf
-      atk
-    ]);
   };
 }
diff --git a/nixos/tests/installer.nix b/nixos/tests/installer.nix
index eef9abebf9f25..d80cfb4bd83f2 100644
--- a/nixos/tests/installer.nix
+++ b/nixos/tests/installer.nix
@@ -64,7 +64,7 @@ let
   # a test script fragment `createPartitions', which must create
   # partitions and filesystems.
   testScriptFun = { bootLoader, createPartitions, grubVersion, grubDevice, grubUseEfi
-                  , grubIdentifier, preBootCommands, extraConfig
+                  , grubIdentifier, preBootCommands, postBootCommands, extraConfig
                   , testSpecialisationConfig
                   }:
     let iface = if grubVersion == 1 then "ide" else "virtio";
@@ -74,7 +74,7 @@ let
       throw "Non-EFI boot methods are only supported on i686 / x86_64"
     else ''
       def assemble_qemu_flags():
-          flags = "-cpu host"
+          flags = "-cpu max"
           ${if system == "x86_64-linux"
             then ''flags += " -m 768"''
             else ''flags += " -m 512 -enable-kvm -machine virt,gic-version=host"''
@@ -216,6 +216,7 @@ let
       machine = create_machine_named("boot-after-rebuild-switch")
       ${preBootCommands}
       machine.wait_for_unit("network.target")
+      ${postBootCommands}
       machine.shutdown()
 
       # Tests for validating clone configuration entries in grub menu
@@ -238,6 +239,7 @@ let
       with subtest("Set grub to boot the second configuration"):
           machine.succeed("grub-reboot 1")
 
+      ${postBootCommands}
       machine.shutdown()
 
       # Reboot Machine
@@ -252,12 +254,13 @@ let
       with subtest("We should find a file named /etc/gitconfig"):
           machine.succeed("test -e /etc/gitconfig")
 
+      ${postBootCommands}
       machine.shutdown()
     '';
 
 
   makeInstallerTest = name:
-    { createPartitions, preBootCommands ? "", extraConfig ? ""
+    { createPartitions, preBootCommands ? "", postBootCommands ? "", extraConfig ? ""
     , extraInstallerConfig ? {}
     , bootLoader ? "grub" # either "grub" or "systemd-boot"
     , grubVersion ? 2, grubDevice ? "/dev/vda", grubIdentifier ? "uuid", grubUseEfi ? false
@@ -282,7 +285,7 @@ let
           ];
 
           virtualisation.diskSize = 8 * 1024;
-          virtualisation.memorySize = 1024;
+          virtualisation.memorySize = 1536;
 
           # Use a small /dev/vdb as the root disk for the
           # installer. This ensures the target disk (/dev/vda) is
@@ -335,7 +338,7 @@ let
       };
 
       testScript = testScriptFun {
-        inherit bootLoader createPartitions preBootCommands
+        inherit bootLoader createPartitions preBootCommands postBootCommands
                 grubVersion grubDevice grubIdentifier grubUseEfi extraConfig
                 testSpecialisationConfig;
       };
@@ -552,16 +555,26 @@ in {
           + " mkpart primary 2048M -1s"  # PV2
           + " set 2 lvm on",
           "udevadm settle",
+          "sleep 1",
           "pvcreate /dev/vda1 /dev/vda2",
+          "sleep 1",
           "vgcreate MyVolGroup /dev/vda1 /dev/vda2",
+          "sleep 1",
           "lvcreate --size 1G --name swap MyVolGroup",
-          "lvcreate --size 2G --name nixos MyVolGroup",
+          "sleep 1",
+          "lvcreate --size 3G --name nixos MyVolGroup",
+          "sleep 1",
           "mkswap -f /dev/MyVolGroup/swap -L swap",
           "swapon -L swap",
           "mkfs.xfs -L nixos /dev/MyVolGroup/nixos",
           "mount LABEL=nixos /mnt",
       )
     '';
+    postBootCommands = ''
+      assert "loaded active" in machine.succeed(
+          "systemctl list-units 'lvm2-pvscan@*' -ql --no-legend | tee /dev/stderr"
+      )
+    '';
   };
 
   # Boot off an encrypted root partition with the default LUKS header format
@@ -620,10 +633,10 @@ in {
           + " mklabel msdos"
           + " mkpart primary ext2 1M 100MB"  # /boot
           + " mkpart extended 100M -1s"
-          + " mkpart logical 102M 2102M"  # md0 (root), first device
-          + " mkpart logical 2103M 4103M"  # md0 (root), second device
-          + " mkpart logical 4104M 4360M"  # md1 (swap), first device
-          + " mkpart logical 4361M 4617M",  # md1 (swap), second device
+          + " mkpart logical 102M 3102M"  # md0 (root), first device
+          + " mkpart logical 3103M 6103M"  # md0 (root), second device
+          + " mkpart logical 6104M 6360M"  # md1 (swap), first device
+          + " mkpart logical 6361M 6617M",  # md1 (swap), second device
           "udevadm settle",
           "ls -l /dev/vda* >&2",
           "cat /proc/partitions >&2",
@@ -786,7 +799,7 @@ in {
           "btrfs subvol create /mnt/badpath/boot",
           "btrfs subvol create /mnt/nixos",
           "btrfs subvol set-default "
-          + "$(btrfs subvol list /mnt | grep 'nixos' | awk '{print \$2}') /mnt",
+          + "$(btrfs subvol list /mnt | grep 'nixos' | awk '{print $2}') /mnt",
           "umount /mnt",
           "mount -o defaults LABEL=root /mnt",
           "mkdir -p /mnt/badpath/boot",  # Help ensure the detection mechanism
diff --git a/nixos/tests/jitsi-meet.nix b/nixos/tests/jitsi-meet.nix
new file mode 100644
index 0000000000000..42762dfdad8e0
--- /dev/null
+++ b/nixos/tests/jitsi-meet.nix
@@ -0,0 +1,55 @@
+import ./make-test-python.nix ({ pkgs, ... }: {
+  name = "jitsi-meet";
+  meta = with pkgs.stdenv.lib; {
+    maintainers = teams.jitsi.members;
+  };
+
+  nodes = {
+    client = { nodes, pkgs, ... }: {
+    };
+    server = { config, pkgs, ... }: {
+      services.jitsi-meet = {
+        enable = true;
+        hostName = "server";
+      };
+      services.jitsi-videobridge.openFirewall = true;
+
+      networking.firewall.allowedTCPPorts = [ 80 443 ];
+
+      services.nginx.virtualHosts.server = {
+        enableACME = true;
+        forceSSL = true;
+      };
+
+      security.acme.email = "me@example.org";
+      security.acme.acceptTerms = true;
+      security.acme.server = "https://example.com"; # self-signed only
+    };
+  };
+
+  testScript = ''
+    server.wait_for_unit("jitsi-videobridge2.service")
+    server.wait_for_unit("jicofo.service")
+    server.wait_for_unit("nginx.service")
+    server.wait_for_unit("prosody.service")
+
+    server.wait_until_succeeds(
+        "journalctl -b -u jitsi-videobridge2 -o cat | grep -q 'Performed a successful health check'"
+    )
+    server.wait_until_succeeds(
+        "journalctl -b -u jicofo -o cat | grep -q 'connected .JID: focus@auth.server'"
+    )
+    server.wait_until_succeeds(
+        "journalctl -b -u prosody -o cat | grep -q 'Authenticated as focus@auth.server'"
+    )
+    server.wait_until_succeeds(
+        "journalctl -b -u prosody -o cat | grep -q 'focus.server:component: External component successfully authenticated'"
+    )
+    server.wait_until_succeeds(
+        "journalctl -b -u prosody -o cat | grep -q 'Authenticated as jvb@auth.server'"
+    )
+
+    client.wait_for_unit("network.target")
+    assert "<title>Jitsi Meet</title>" in client.succeed("curl -sSfkL http://server/")
+  '';
+})
diff --git a/nixos/tests/krb5/example-config.nix b/nixos/tests/krb5/example-config.nix
index be195b5139352..e2e10a9fda892 100644
--- a/nixos/tests/krb5/example-config.nix
+++ b/nixos/tests/krb5/example-config.nix
@@ -18,7 +18,10 @@ import ../make-test-python.nix ({ pkgs, ...} : {
         realms = {
           "ATHENA.MIT.EDU" = {
             admin_server = "athena.mit.edu";
-            kdc = "athena.mit.edu";
+            kdc = [
+              "athena01.mit.edu"
+              "athena02.mit.edu"
+            ];
           };
         };
         domain_realm = {
@@ -65,7 +68,8 @@ import ../make-test-python.nix ({ pkgs, ...} : {
       [realms]
         ATHENA.MIT.EDU = {
           admin_server = athena.mit.edu
-          kdc = athena.mit.edu
+          kdc = athena01.mit.edu
+          kdc = athena02.mit.edu
         }
 
       [domain_realm]
diff --git a/nixos/tests/kubernetes/base.nix b/nixos/tests/kubernetes/base.nix
index 86de9455e7374..8cfac10b6dc47 100644
--- a/nixos/tests/kubernetes/base.nix
+++ b/nixos/tests/kubernetes/base.nix
@@ -9,7 +9,6 @@ with pkgs.lib;
 let
   mkKubernetesBaseTest =
     { name, domain ? "my.zyx", test, machines
-    , pkgs ? import <nixpkgs> { inherit system; }
     , extraConfiguration ? null }:
     let
       masterName = head (filter (machineName: any (role: role == "master") machines.${machineName}.roles) (attrNames machines));
diff --git a/nixos/tests/leaps.nix b/nixos/tests/leaps.nix
index 65b475d734ec8..ac0c602d44504 100644
--- a/nixos/tests/leaps.nix
+++ b/nixos/tests/leaps.nix
@@ -7,7 +7,7 @@ import ./make-test-python.nix ({ pkgs,  ... }:
   };
 
   nodes =
-    { 
+    {
       client = { };
 
       server =
diff --git a/nixos/tests/lorri/default.nix b/nixos/tests/lorri/default.nix
index 198171082d880..c33c7503993da 100644
--- a/nixos/tests/lorri/default.nix
+++ b/nixos/tests/lorri/default.nix
@@ -18,7 +18,7 @@ import ../make-test-python.nix {
     machine.wait_until_succeeds("grep --fixed-strings 'ready' lorri.stdout")
 
     # Ping the daemon
-    machine.succeed("lorri internal__ping shell.nix")
+    machine.succeed("lorri internal ping shell.nix")
 
     # Wait for the daemon to finish the build
     machine.wait_until_succeeds("grep --fixed-strings 'Completed' lorri.stdout")
diff --git a/nixos/tests/lxd-nftables.nix b/nixos/tests/lxd-nftables.nix
index 25517914db857..4ca02067a0ae0 100644
--- a/nixos/tests/lxd-nftables.nix
+++ b/nixos/tests/lxd-nftables.nix
@@ -7,6 +7,7 @@
 
 import ./make-test-python.nix ({ pkgs, ...} : {
   name = "lxd-nftables";
+
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ patryk27 ];
   };
diff --git a/nixos/tests/lxd.nix b/nixos/tests/lxd.nix
index db2d44dff5575..d1e642383cf86 100644
--- a/nixos/tests/lxd.nix
+++ b/nixos/tests/lxd.nix
@@ -6,15 +6,14 @@ let
   #
   # I've chosen to import Alpine Linux, because its image is turbo-tiny and,
   # generally, sufficient for our tests.
-
   alpine-meta = pkgs.fetchurl {
-    url = "https://uk.images.linuxcontainers.org/images/alpine/3.11/i386/default/20200608_13:00/lxd.tar.xz";
-    sha256 = "1hkvaj3rr333zmx1759njy435lps33gl4ks8zfm7m4nqvipm26a0";
+    url = "https://tarballs.nixos.org/alpine/3.12/lxd.tar.xz";
+    hash = "sha256-1tcKaO9lOkvqfmG/7FMbfAEToAuFy2YMewS8ysBKuLA=";
   };
 
   alpine-rootfs = pkgs.fetchurl {
-    url = "https://uk.images.linuxcontainers.org/images/alpine/3.11/i386/default/20200608_13:00/rootfs.tar.xz";
-    sha256 = "1v82zdra4j5xwsff09qlp7h5vbsg54s0j7rdg4rynichfid3r347";
+    url = "https://tarballs.nixos.org/alpine/3.12/rootfs.tar.xz";
+    hash = "sha256-Tba9sSoaiMtQLY45u7p5DMqXTSDgs/763L/SQp0bkCA=";
   };
 
   lxd-config = pkgs.writeText "config.yaml" ''
@@ -44,8 +43,10 @@ let
             type: disk
   '';
 
+
 in {
   name = "lxd";
+
   meta = with pkgs.stdenv.lib.maintainers; {
     maintainers = [ patryk27 ];
   };
@@ -53,7 +54,7 @@ in {
   machine = { lib, ... }: {
     virtualisation = {
       # Since we're testing `limits.cpu`, we've gotta have a known number of
-      # cores to lay on
+      # cores to lean on
       cores = 2;
 
       # Ditto, for `limits.memory`
@@ -67,6 +68,7 @@ in {
   testScript = ''
     machine.wait_for_unit("sockets.target")
     machine.wait_for_unit("lxd.service")
+    machine.wait_for_file("/var/lib/lxd/unix.socket")
 
     # It takes additional second for lxd to settle
     machine.sleep(1)
diff --git a/nixos/tests/make-test.nix b/nixos/tests/make-test.nix
deleted file mode 100644
index cee5da93454a1..0000000000000
--- a/nixos/tests/make-test.nix
+++ /dev/null
@@ -1,9 +0,0 @@
-f: {
-  system ? builtins.currentSystem,
-  pkgs ? import ../.. { inherit system; config = {}; },
-  ...
-} @ args:
-
-with import ../lib/testing.nix { inherit system pkgs; };
-
-makeTest (if pkgs.lib.isFunction f then f (args // { inherit pkgs; inherit (pkgs) lib; }) else f)
diff --git a/nixos/tests/mathics.nix b/nixos/tests/mathics.nix
deleted file mode 100644
index fcbeeb18a7271..0000000000000
--- a/nixos/tests/mathics.nix
+++ /dev/null
@@ -1,20 +0,0 @@
-import ./make-test.nix ({ pkgs, ... }: {
-  name = "mathics";
-  meta = with pkgs.stdenv.lib.maintainers; {
-    maintainers = [ benley ];
-  };
-
-  nodes = {
-    machine = { ... }: {
-      services.mathics.enable = true;
-      services.mathics.port = 8888;
-    };
-  };
-
-  testScript = ''
-    startAll;
-    $machine->waitForUnit("mathics.service");
-    $machine->waitForOpenPort(8888);
-    $machine->succeed("curl http://localhost:8888/");
-  '';
-})
diff --git a/nixos/tests/mesos.nix b/nixos/tests/mesos.nix
deleted file mode 100644
index 2e6dc0eda063c..0000000000000
--- a/nixos/tests/mesos.nix
+++ /dev/null
@@ -1,92 +0,0 @@
-import ./make-test.nix ({ pkgs, ...} : rec {
-  name = "mesos";
-  meta = with pkgs.stdenv.lib.maintainers; {
-    maintainers = [ offline kamilchm cstrahan ];
-  };
-
-  nodes = {
-    master = { ... }: {
-      networking.firewall.enable = false;
-      services.zookeeper.enable = true;
-      services.mesos.master = {
-          enable = true;
-          zk = "zk://master:2181/mesos";
-      };
-    };
-
-    slave = { ... }: {
-      networking.firewall.enable = false;
-      networking.nat.enable = true;
-      virtualisation.docker.enable = true;
-      services.mesos = {
-        slave = {
-          enable = true;
-          master = "master:5050";
-          dockerRegistry = registry;
-          executorEnvironmentVariables = {
-            PATH = "/run/current-system/sw/bin";
-          };
-        };
-      };
-    };
-  };
-
-  simpleDocker = pkgs.dockerTools.buildImage {
-    name = "echo";
-    tag = "latest";
-    contents = [ pkgs.stdenv.shellPackage pkgs.coreutils ];
-    config = {
-      Env = [
-        # When shell=true, mesos invokes "sh -c '<cmd>'", so make sure "sh" is
-        # on the PATH.
-        "PATH=${pkgs.stdenv.shellPackage}/bin:${pkgs.coreutils}/bin"
-      ];
-      Entrypoint = [ "echo" ];
-    };
-  };
-
-  registry = pkgs.runCommand "registry" { } ''
-    mkdir -p $out
-    cp ${simpleDocker} $out/echo:latest.tar
-  '';
-
-  testFramework = pkgs.pythonPackages.buildPythonPackage {
-    name = "mesos-tests";
-    propagatedBuildInputs = [ pkgs.mesos ];
-    catchConflicts = false;
-    src = ./mesos_test.py;
-    phases = [ "installPhase" "fixupPhase" ];
-    installPhase = ''
-      install -Dvm 0755 $src $out/bin/mesos_test.py
-
-      echo "done" > test.result
-      tar czf $out/test.tar.gz test.result
-    '';
-  };
-
-  testScript =
-    ''
-      startAll;
-      $master->waitForUnit("zookeeper.service");
-      $master->waitForUnit("mesos-master.service");
-      $slave->waitForUnit("docker.service");
-      $slave->waitForUnit("mesos-slave.service");
-      $master->waitForOpenPort(2181);
-      $master->waitForOpenPort(5050);
-      $slave->waitForOpenPort(5051);
-
-      # is slave registered?
-      $master->waitUntilSucceeds("curl -s --fail http://master:5050/master/slaves".
-                                 " | grep -q \"\\\"hostname\\\":\\\"slave\\\"\"");
-
-      # try to run docker image
-      $master->succeed("${pkgs.mesos}/bin/mesos-execute --master=master:5050".
-                       " --resources=\"cpus:0.1;mem:32\" --name=simple-docker".
-                       " --containerizer=mesos --docker_image=echo:latest".
-                       " --shell=true --command=\"echo done\" | grep -q TASK_FINISHED");
-
-      # simple command with .tar.gz uri
-      $master->succeed("${testFramework}/bin/mesos_test.py master ".
-                       "${testFramework}/test.tar.gz");
-    '';
-})
diff --git a/nixos/tests/mesos_test.py b/nixos/tests/mesos_test.py
deleted file mode 100644
index be8bb32e49a7e..0000000000000
--- a/nixos/tests/mesos_test.py
+++ /dev/null
@@ -1,72 +0,0 @@
-#!/usr/bin/env python
-import uuid
-import time
-import subprocess
-import os
-
-import sys
-
-from mesos.interface import Scheduler
-from mesos.native import MesosSchedulerDriver
-from mesos.interface import mesos_pb2
-
-def log(msg):
-    process = subprocess.Popen("systemd-cat", stdin=subprocess.PIPE)
-    (out,err) = process.communicate(msg)
-
-class NixosTestScheduler(Scheduler):
-    def __init__(self):
-        self.master_ip = sys.argv[1]
-        self.download_uri = sys.argv[2]
-
-    def resourceOffers(self, driver, offers):
-        log("XXX got resource offer")
-
-        offer = offers[0]
-        task = self.new_task(offer)
-        uri = task.command.uris.add()
-        uri.value = self.download_uri
-        task.command.value = "cat test.result"
-        driver.launchTasks(offer.id, [task])
-
-    def statusUpdate(self, driver, update):
-        log("XXX status update")
-        if update.state == mesos_pb2.TASK_FAILED:
-            log("XXX test task failed with message: " + update.message)
-            driver.stop()
-            sys.exit(1)
-        elif update.state == mesos_pb2.TASK_FINISHED:
-            driver.stop()
-            sys.exit(0)
-
-    def new_task(self, offer):
-        task = mesos_pb2.TaskInfo()
-        id = uuid.uuid4()
-        task.task_id.value = str(id)
-        task.slave_id.value = offer.slave_id.value
-        task.name = "task {}".format(str(id))
-
-        cpus = task.resources.add()
-        cpus.name = "cpus"
-        cpus.type = mesos_pb2.Value.SCALAR
-        cpus.scalar.value = 0.1
-
-        mem = task.resources.add()
-        mem.name = "mem"
-        mem.type = mesos_pb2.Value.SCALAR
-        mem.scalar.value = 32
-
-        return task
-
-if __name__ == '__main__':
-    log("XXX framework started")
-
-    framework = mesos_pb2.FrameworkInfo()
-    framework.user = "root"
-    framework.name = "nixos-test-framework"
-    driver = MesosSchedulerDriver(
-        NixosTestScheduler(),
-        framework,
-        sys.argv[1] + ":5050"
-    )
-    driver.run()
diff --git a/nixos/tests/misc.nix b/nixos/tests/misc.nix
index 17260ce640676..ae15055327343 100644
--- a/nixos/tests/misc.nix
+++ b/nixos/tests/misc.nix
@@ -20,12 +20,24 @@ import ./make-test-python.nix ({ pkgs, ...} : rec {
         { fsType = "tmpfs";
           options = [ "mode=1777" "noauto" ];
         };
+        # Tests https://discourse.nixos.org/t/how-to-make-a-derivations-executables-have-the-s-permission/8555
+        "/user-mount/point" = {
+          device = "/user-mount/source";
+          fsType = "none";
+          options = [ "bind" "rw" "user" "noauto" ];
+        };
+        "/user-mount/denied-point" = {
+          device = "/user-mount/denied-source";
+          fsType = "none";
+          options = [ "bind" "rw" "noauto" ];
+        };
       };
       systemd.automounts = singleton
         { wantedBy = [ "multi-user.target" ];
           where = "/tmp2";
         };
       users.users.sybil = { isNormalUser = true; group = "wheel"; };
+      users.users.alice = { isNormalUser = true; };
       security.sudo = { enable = true; wheelNeedsPassword = false; };
       boot.kernel.sysctl."vm.swappiness" = 1;
       boot.kernelParams = [ "vsyscall=emulate" ];
@@ -112,6 +124,26 @@ import ./make-test-python.nix ({ pkgs, ...} : rec {
           machine.succeed("touch /tmp2/x")
           machine.succeed("grep '/tmp2 tmpfs' /proc/mounts")
 
+      with subtest(
+          "Whether mounting by a user is possible with the `user` option in fstab (#95444)"
+      ):
+          machine.succeed("mkdir -p /user-mount/source")
+          machine.succeed("touch /user-mount/source/file")
+          machine.succeed("chmod -R a+Xr /user-mount/source")
+          machine.succeed("mkdir /user-mount/point")
+          machine.succeed("chown alice:users /user-mount/point")
+          machine.succeed("su - alice -c 'mount /user-mount/point'")
+          machine.succeed("su - alice -c 'ls /user-mount/point/file'")
+      with subtest(
+          "Whether mounting by a user is denied without the `user` option in  fstab"
+      ):
+          machine.succeed("mkdir -p /user-mount/denied-source")
+          machine.succeed("touch /user-mount/denied-source/file")
+          machine.succeed("chmod -R a+Xr /user-mount/denied-source")
+          machine.succeed("mkdir /user-mount/denied-point")
+          machine.succeed("chown alice:users /user-mount/denied-point")
+          machine.fail("su - alice -c 'mount /user-mount/denied-point'")
+
       with subtest("shell-vars"):
           machine.succeed('[ -n "$NIX_PATH" ]')
 
diff --git a/nixos/tests/molly-brown.nix b/nixos/tests/molly-brown.nix
new file mode 100644
index 0000000000000..09ce42726ca98
--- /dev/null
+++ b/nixos/tests/molly-brown.nix
@@ -0,0 +1,71 @@
+import ./make-test-python.nix ({ pkgs, ... }:
+
+  let testString = "NixOS Gemini test successful";
+  in {
+
+    name = "molly-brown";
+    meta = with pkgs.stdenv.lib.maintainers; { maintainers = [ ehmry ]; };
+
+    nodes = {
+
+      geminiServer = { config, pkgs, ... }:
+        let
+          inherit (config.networking) hostName;
+          cfg = config.services.molly-brown;
+        in {
+
+          environment.systemPackages = [
+            (pkgs.writeScriptBin "test-gemini" ''
+              #!${pkgs.python3}/bin/python
+
+              import socket
+              import ssl
+              import tempfile
+              import textwrap
+              import urllib.parse
+
+              url = "gemini://geminiServer/init.gmi"
+              parsed_url = urllib.parse.urlparse(url)
+
+              s = socket.create_connection((parsed_url.netloc, 1965))
+              context = ssl.SSLContext()
+              context.check_hostname = False
+              context.verify_mode = ssl.CERT_NONE
+              s = context.wrap_socket(s, server_hostname=parsed_url.netloc)
+              s.sendall((url + "\r\n").encode("UTF-8"))
+              fp = s.makefile("rb")
+              print(fp.readline().strip())
+              print(fp.readline().strip())
+              print(fp.readline().strip())
+            '')
+          ];
+
+          networking.firewall.allowedTCPPorts = [ cfg.settings.Port ];
+
+          services.molly-brown = {
+            enable = true;
+            docBase = "/tmp/docs";
+            certPath = "/tmp/cert.pem";
+            keyPath = "/tmp/key.pem";
+          };
+
+          systemd.services.molly-brown.preStart = ''
+            ${pkgs.openssl}/bin/openssl genrsa -out "/tmp/key.pem"
+            ${pkgs.openssl}/bin/openssl req -new \
+              -subj "/CN=${config.networking.hostName}" \
+              -key "/tmp/key.pem" -out /tmp/request.pem
+            ${pkgs.openssl}/bin/openssl x509 -req -days 3650 \
+              -in /tmp/request.pem -signkey "/tmp/key.pem" -out "/tmp/cert.pem"
+
+            mkdir -p "${cfg.settings.DocBase}"
+            echo "${testString}" > "${cfg.settings.DocBase}/test.gmi"
+          '';
+        };
+    };
+    testScript = ''
+      geminiServer.wait_for_unit("molly-brown")
+      geminiServer.wait_for_open_port(1965)
+      geminiServer.succeed("test-gemini")
+    '';
+
+  })
diff --git a/nixos/tests/mongodb.nix b/nixos/tests/mongodb.nix
index a637ec4bfc00f..1a71238830189 100644
--- a/nixos/tests/mongodb.nix
+++ b/nixos/tests/mongodb.nix
@@ -15,7 +15,7 @@ import ./make-test-python.nix ({ pkgs, ... }:
       node.wait_for_open_port(27017)
 
       assert "hello" in node.succeed(
-          "mongo ${testQuery}"
+          "${pkg}/bin/mongo ${testQuery}"
       )
 
       node.execute(
@@ -36,6 +36,7 @@ import ./make-test-python.nix ({ pkgs, ... }:
           mongodb-3_4
           mongodb-3_6
           mongodb-4_0
+          mongodb-4_2
         ];
       };
     };
@@ -44,8 +45,9 @@ import ./make-test-python.nix ({ pkgs, ... }:
       node.start()
     ''
       + runMongoDBTest pkgs.mongodb-3_4
-      + runMongoDBTest pkgs.mongodb-3_6 
+      + runMongoDBTest pkgs.mongodb-3_6
       + runMongoDBTest pkgs.mongodb-4_0
+      + runMongoDBTest pkgs.mongodb-4_2
       + ''
         node.shutdown()
       '';
diff --git a/nixos/tests/mysql/mysql.nix b/nixos/tests/mysql/mysql.nix
index 50e1c76e9fd0e..5437a2860437e 100644
--- a/nixos/tests/mysql/mysql.nix
+++ b/nixos/tests/mysql/mysql.nix
@@ -172,32 +172,32 @@ import ./../make-test-python.nix ({ pkgs, ...} : {
         "echo 'use testdb; select test_id from tests;' | sudo -u testuser mysql -u testuser -N | grep 42"
     )
 
-    # Check if TokuDB plugin works
+    # Check if RocksDB plugin works
     mariadb.succeed(
-        "echo 'use testdb; create table tokudb (test_id INT, PRIMARY KEY (test_id)) ENGINE = TokuDB;' | sudo -u testuser mysql -u testuser"
+        "echo 'use testdb; create table rocksdb (test_id INT, PRIMARY KEY (test_id)) ENGINE = RocksDB;' | sudo -u testuser mysql -u testuser"
     )
     mariadb.succeed(
-        "echo 'use testdb; insert into tokudb values (25);' | sudo -u testuser mysql -u testuser"
+        "echo 'use testdb; insert into rocksdb values (28);' | sudo -u testuser mysql -u testuser"
     )
     mariadb.succeed(
-        "echo 'use testdb; select test_id from tokudb;' | sudo -u testuser mysql -u testuser -N | grep 25"
+        "echo 'use testdb; select test_id from rocksdb;' | sudo -u testuser mysql -u testuser -N | grep 28"
     )
     mariadb.succeed(
-        "echo 'use testdb; drop table tokudb;' | sudo -u testuser mysql -u testuser"
+        "echo 'use testdb; drop table rocksdb;' | sudo -u testuser mysql -u testuser"
     )
-
-    # Check if RocksDB plugin works
+  '' + pkgs.stdenv.lib.optionalString pkgs.stdenv.isx86_64 ''
+    # Check if TokuDB plugin works
     mariadb.succeed(
-        "echo 'use testdb; create table rocksdb (test_id INT, PRIMARY KEY (test_id)) ENGINE = RocksDB;' | sudo -u testuser mysql -u testuser"
+        "echo 'use testdb; create table tokudb (test_id INT, PRIMARY KEY (test_id)) ENGINE = TokuDB;' | sudo -u testuser mysql -u testuser"
     )
     mariadb.succeed(
-        "echo 'use testdb; insert into rocksdb values (28);' | sudo -u testuser mysql -u testuser"
+        "echo 'use testdb; insert into tokudb values (25);' | sudo -u testuser mysql -u testuser"
     )
     mariadb.succeed(
-        "echo 'use testdb; select test_id from rocksdb;' | sudo -u testuser mysql -u testuser -N | grep 28"
+        "echo 'use testdb; select test_id from tokudb;' | sudo -u testuser mysql -u testuser -N | grep 25"
     )
     mariadb.succeed(
-        "echo 'use testdb; drop table rocksdb;' | sudo -u testuser mysql -u testuser"
+        "echo 'use testdb; drop table tokudb;' | sudo -u testuser mysql -u testuser"
     )
   '';
 })
diff --git a/nixos/tests/ncdns.nix b/nixos/tests/ncdns.nix
new file mode 100644
index 0000000000000..507e20fe7cc46
--- /dev/null
+++ b/nixos/tests/ncdns.nix
@@ -0,0 +1,77 @@
+import ./make-test-python.nix ({ pkgs, ... }:
+let
+  fakeReply = pkgs.writeText "namecoin-reply.json" ''
+  { "error": null,
+    "id": 1,
+    "result": {
+      "address": "T31q8ucJ4dI1xzhxQ5QispfECld5c7Xw",
+      "expired": false,
+      "expires_in": 2248,
+      "height": 438155,
+      "name": "d/test",
+      "txid": "db61c0b2540ba0c1a2c8cc92af703a37002e7566ecea4dbf8727c7191421edfb",
+      "value": "{\"ip\": \"1.2.3.4\", \"email\": \"root@test.bit\",\"info\": \"Fake record\"}",
+      "vout": 0
+    }
+  }
+  '';
+in
+
+{
+  name = "ncdns";
+
+  nodes.server = { ... }: {
+    networking.nameservers = [ "127.0.0.1" ];
+
+    services.namecoind.rpc = {
+      address = "127.0.0.1";
+      user = "namecoin";
+      password = "secret";
+      port = 8332;
+    };
+
+    # Fake namecoin RPC server because we can't
+    # run a full node in a test.
+    systemd.services.namecoind = {
+      wantedBy = [ "multi-user.target" ];
+      script = ''
+        while true; do
+          echo -e "HTTP/1.1 200 OK\n\n $(<${fakeReply})\n" \
+            | ${pkgs.netcat}/bin/nc -N -l 127.0.0.1 8332
+        done
+      '';
+    };
+
+    services.ncdns = {
+      enable = true;
+      dnssec.enable = true;
+    };
+
+    services.pdns-recursor = {
+      enable = true;
+      dns.allowFrom = [ "127.0.0.0/8" ];
+      settings.loglevel = 8;
+      resolveNamecoin = true;
+    };
+
+    environment.systemPackages = [ pkgs.dnsutils ];
+
+  };
+
+  testScript = ''
+    with subtest("DNSSEC keys have been generated"):
+        server.wait_for_unit("ncdns")
+        server.wait_for_file("/var/lib/ncdns/bit.key")
+        server.wait_for_file("/var/lib/ncdns/bit-zone.key")
+
+    with subtest("DNSKEY bit record is present"):
+        server.wait_for_unit("pdns-recursor")
+        server.wait_for_open_port("53")
+        server.succeed("host -t DNSKEY bit")
+
+    with subtest("can resolve a .bit name"):
+        server.wait_for_unit("namecoind")
+        server.wait_for_open_port("8332")
+        assert "1.2.3.4" in server.succeed("host -t A test.bit")
+  '';
+})
diff --git a/nixos/tests/networking.nix b/nixos/tests/networking.nix
index 3d8ab761a4464..83d4f6465b686 100644
--- a/nixos/tests/networking.nix
+++ b/nixos/tests/networking.nix
@@ -8,7 +8,9 @@ with import ../lib/testing-python.nix { inherit system pkgs; };
 with pkgs.lib;
 
 let
-  router = { config, pkgs, ... }:
+  qemu-flags = import ../lib/qemu-flags.nix { inherit pkgs; };
+
+  router = { config, pkgs, lib, ... }:
     with pkgs.lib;
     let
       vlanIfs = range 1 (length config.virtualisation.vlans);
@@ -30,17 +32,20 @@ let
       services.dhcpd4 = {
         enable = true;
         interfaces = map (n: "eth${toString n}") vlanIfs;
-        extraConfig = ''
-          authoritative;
-        '' + flip concatMapStrings vlanIfs (n: ''
+        extraConfig = flip concatMapStrings vlanIfs (n: ''
           subnet 192.168.${toString n}.0 netmask 255.255.255.0 {
             option routers 192.168.${toString n}.1;
-            # XXX: technically it's _not guaranteed_ that IP addresses will be
-            # issued from the first item in range onwards! We assume that in
-            # our tests however.
             range 192.168.${toString n}.2 192.168.${toString n}.254;
           }
-        '');
+        '')
+        ;
+        machines = flip map vlanIfs (vlan:
+          {
+            hostName = "client${toString vlan}";
+            ethernetAddress = qemu-flags.qemuNicMac vlan 1;
+            ipAddress = "192.168.${toString vlan}.2";
+          }
+        );
       };
       services.radvd = {
         enable = true;
diff --git a/nixos/tests/nextcloud/basic.nix b/nixos/tests/nextcloud/basic.nix
index 9cbecf01f57b7..72fb020dca708 100644
--- a/nixos/tests/nextcloud/basic.nix
+++ b/nixos/tests/nextcloud/basic.nix
@@ -26,12 +26,13 @@ in {
       };
     };
 
-    nextcloud = { config, pkgs, ... }: {
+    nextcloud = { config, pkgs, ... }: let
+      cfg = config;
+    in {
       networking.firewall.allowedTCPPorts = [ 80 ];
 
       services.nextcloud = {
         enable = true;
-        nginx.enable = true;
         hostName = "nextcloud";
         config = {
           # Don't inherit adminuser since "root" is supposed to be the default
@@ -42,6 +43,8 @@ in {
           startAt = "20:00";
         };
       };
+
+      environment.systemPackages = [ cfg.services.nextcloud.occ ];
     };
   };
 
@@ -67,6 +70,8 @@ in {
   in ''
     start_all()
     nextcloud.wait_for_unit("multi-user.target")
+    # This is just to ensure the nextcloud-occ program is working
+    nextcloud.succeed("nextcloud-occ status")
     nextcloud.succeed("curl -sSf http://nextcloud/login")
     nextcloud.succeed(
         "${withRcloneEnv} ${copySharedFile}"
diff --git a/nixos/tests/nextcloud/with-mysql-and-memcached.nix b/nixos/tests/nextcloud/with-mysql-and-memcached.nix
index 8db630be893af..bec3815a3e14c 100644
--- a/nixos/tests/nextcloud/with-mysql-and-memcached.nix
+++ b/nixos/tests/nextcloud/with-mysql-and-memcached.nix
@@ -17,7 +17,6 @@ in {
       services.nextcloud = {
         enable = true;
         hostName = "nextcloud";
-        nginx.enable = true;
         https = true;
         caching = {
           apcu = true;
diff --git a/nixos/tests/nextcloud/with-postgresql-and-redis.nix b/nixos/tests/nextcloud/with-postgresql-and-redis.nix
index 95219cac9be8e..40a208115c32c 100644
--- a/nixos/tests/nextcloud/with-postgresql-and-redis.nix
+++ b/nixos/tests/nextcloud/with-postgresql-and-redis.nix
@@ -17,7 +17,6 @@ in {
       services.nextcloud = {
         enable = true;
         hostName = "nextcloud";
-        nginx.enable = true;
         caching = {
           apcu = false;
           redis = true;
diff --git a/nixos/tests/nfs/kerberos.nix b/nixos/tests/nfs/kerberos.nix
index 1f2d0d453ea0c..078f0b7814cea 100644
--- a/nixos/tests/nfs/kerberos.nix
+++ b/nixos/tests/nfs/kerberos.nix
@@ -3,7 +3,7 @@ import ../make-test-python.nix ({ pkgs, lib, ... }:
 with lib;
 
 let
-  krb5 = 
+  krb5 =
     { enable = true;
       domain_realm."nfs.test"   = "NFS.TEST";
       libdefaults.default_realm = "NFS.TEST";
@@ -31,7 +31,7 @@ in
 
 {
   name = "nfsv4-with-kerberos";
- 
+
   nodes = {
     client = { lib, ... }:
       { inherit krb5 users;
diff --git a/nixos/tests/nginx-sandbox.nix b/nixos/tests/nginx-sandbox.nix
index bc9d3ba8add7e..514318c9456c4 100644
--- a/nixos/tests/nginx-sandbox.nix
+++ b/nixos/tests/nginx-sandbox.nix
@@ -18,7 +18,6 @@ import ./make-test-python.nix ({ pkgs, ... }: {
     ];
     services.nginx.enable = true;
     services.nginx.package = pkgs.nginx-lua;
-    services.nginx.enableSandbox = true;
     services.nginx.virtualHosts.localhost = {
       extraConfig = ''
         location /test1-write {
diff --git a/nixos/tests/nginx-variants.nix b/nixos/tests/nginx-variants.nix
new file mode 100644
index 0000000000000..ca4655391bc59
--- /dev/null
+++ b/nixos/tests/nginx-variants.nix
@@ -0,0 +1,33 @@
+{ system ? builtins.currentSystem,
+  config ? {},
+  pkgs ? import ../.. { inherit system config; }
+}:
+
+with import ../lib/testing-python.nix { inherit system pkgs; };
+
+builtins.listToAttrs (
+  builtins.map
+    (nginxName:
+      {
+        name = nginxName;
+        value = makeTest {
+          name = "nginx-variant-${nginxName}";
+
+          machine = { pkgs, ... }: {
+            services.nginx = {
+              enable = true;
+              virtualHosts.localhost.locations."/".return = "200 'foo'";
+              package = pkgs."${nginxName}";
+            };
+          };
+
+          testScript = ''
+            machine.wait_for_unit("nginx")
+            machine.wait_for_open_port(80)
+            machine.succeed('test "$(curl -fvvv http://localhost/)" = foo')
+          '';
+        };
+      }
+    )
+    [ "nginxStable" "nginxUnstable" "nginxShibboleth" "openresty" "tengine" ]
+)
diff --git a/nixos/tests/openstack-image.nix b/nixos/tests/openstack-image.nix
index 97c9137fe1d67..0b57dfb8e7eb5 100644
--- a/nixos/tests/openstack-image.nix
+++ b/nixos/tests/openstack-image.nix
@@ -3,30 +3,30 @@
   pkgs ? import ../.. { inherit system config; }
 }:
 
-with import ../lib/testing.nix { inherit system pkgs; };
+with import ../lib/testing-python.nix { inherit system pkgs; };
 with pkgs.lib;
 
 with import common/ec2.nix { inherit makeTest pkgs; };
 
 let
-  image =
-    (import ../lib/eval-config.nix {
-      inherit system;
-      modules = [
-        ../maintainers/scripts/openstack/openstack-image.nix
-        ../modules/testing/test-instrumentation.nix
-        ../modules/profiles/qemu-guest.nix
-        {
-          # Needed by nixos-rebuild due to lack of network access.
-          system.extraDependencies = with pkgs; [
-            stdenv
-          ];
-        }
-      ];
-    }).config.system.build.openstackImage + "/nixos.qcow2";
+  image = (import ../lib/eval-config.nix {
+    inherit system;
+    modules = [
+      ../maintainers/scripts/openstack/openstack-image.nix
+      ../modules/testing/test-instrumentation.nix
+      ../modules/profiles/qemu-guest.nix
+      {
+        # Needed by nixos-rebuild due to lack of network access.
+        system.extraDependencies = with pkgs; [
+          stdenv
+        ];
+      }
+    ];
+  }).config.system.build.openstackImage + "/nixos.qcow2";
 
   sshKeys = import ./ssh-keys.nix pkgs;
   snakeOilPrivateKey = sshKeys.snakeOilPrivateKey.text;
+  snakeOilPrivateKeyFile = pkgs.writeText "private-key" snakeOilPrivateKey;
   snakeOilPublicKey = sshKeys.snakeOilPublicKey;
 
 in {
@@ -39,32 +39,36 @@ in {
       SSH_HOST_ED25519_KEY:${replaceStrings ["\n"] ["|"] snakeOilPrivateKey}
     '';
     script = ''
-      $machine->start;
-      $machine->waitForFile("/etc/ec2-metadata/user-data");
-      $machine->waitForUnit("sshd.service");
+      machine.start()
+      machine.wait_for_file("/etc/ec2-metadata/user-data")
+      machine.wait_for_unit("sshd.service")
 
-      $machine->succeed("grep unknown /etc/ec2-metadata/ami-manifest-path");
+      machine.succeed("grep unknown /etc/ec2-metadata/ami-manifest-path")
 
       # We have no keys configured on the client side yet, so this should fail
-      $machine->fail("ssh -o BatchMode=yes localhost exit");
+      machine.fail("ssh -o BatchMode=yes localhost exit")
 
       # Let's install our client private key
-      $machine->succeed("mkdir -p ~/.ssh");
+      machine.succeed("mkdir -p ~/.ssh")
 
-      $machine->succeed("echo '${snakeOilPrivateKey}' > ~/.ssh/id_ed25519");
-      $machine->succeed("chmod 600 ~/.ssh/id_ed25519");
+      machine.copy_from_host_via_shell(
+          "${snakeOilPrivateKeyFile}", "~/.ssh/id_ed25519"
+      )
+      machine.succeed("chmod 600 ~/.ssh/id_ed25519")
 
       # We haven't configured the host key yet, so this should still fail
-      $machine->fail("ssh -o BatchMode=yes localhost exit");
+      machine.fail("ssh -o BatchMode=yes localhost exit")
 
       # Add the host key; ssh should finally succeed
-      $machine->succeed("echo localhost,127.0.0.1 ${snakeOilPublicKey} > ~/.ssh/known_hosts");
-      $machine->succeed("ssh -o BatchMode=yes localhost exit");
+      machine.succeed(
+          "echo localhost,127.0.0.1 ${snakeOilPublicKey} > ~/.ssh/known_hosts"
+      )
+      machine.succeed("ssh -o BatchMode=yes localhost exit")
 
       # Just to make sure resizing is idempotent.
-      $machine->shutdown;
-      $machine->start;
-      $machine->waitForFile("/etc/ec2-metadata/user-data");
+      machine.shutdown()
+      machine.start()
+      machine.wait_for_file("/etc/ec2-metadata/user-data")
     '';
   };
 
@@ -86,9 +90,9 @@ in {
       }
     '';
     script = ''
-      $machine->start;
-      $machine->waitForFile("/etc/testFile");
-      $machine->succeed("cat /etc/testFile | grep -q 'whoa'");
+      machine.start()
+      machine.wait_for_file("/etc/testFile")
+      assert "whoa" in machine.succeed("cat /etc/testFile")
     '';
   };
 }
diff --git a/nixos/tests/os-prober.nix b/nixos/tests/os-prober.nix
index 6a38f5ca531c5..be0235a417536 100644
--- a/nixos/tests/os-prober.nix
+++ b/nixos/tests/os-prober.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({pkgs, lib, ...}:
+import ./make-test-python.nix ({pkgs, lib, ...}:
 let
   # A filesystem image with a (presumably) bootable debian
   debianImage = pkgs.vmTools.diskImageFuns.debian9i386 {
@@ -34,9 +34,6 @@ let
     '';
   };
 
-  # options to add the disk to the test vm
-  QEMU_OPTS = "-drive index=2,file=${debianImage}/disk-image.qcow2,read-only,if=virtio";
-
   # a part of the configuration of the test vm
   simpleConfig = {
     boot.loader.grub = {
@@ -71,7 +68,7 @@ in {
   machine = { config, pkgs, ... }: (simpleConfig // {
       imports = [ ../modules/profiles/installation-device.nix
                   ../modules/profiles/base.nix ];
-      virtualisation.memorySize = 1024;
+      virtualisation.memorySize = 1300;
       # The test cannot access the network, so any packages
       # nixos-rebuild needs must be included in the VM.
       system.extraDependencies = with pkgs;
@@ -99,22 +96,28 @@ in {
 
   testScript = ''
     # hack to add the secondary disk
-    $machine->{startCommand} = "QEMU_OPTS=\"\$QEMU_OPTS \"${lib.escapeShellArg QEMU_OPTS} ".$machine->{startCommand};
+    os.environ[
+        "QEMU_OPTS"
+    ] = "-drive index=2,file=${debianImage}/disk-image.qcow2,read-only,if=virtio"
 
-    $machine->start;
-    $machine->succeed("udevadm settle");
-    $machine->waitForUnit("multi-user.target");
+    machine.start()
+    machine.succeed("udevadm settle")
+    machine.wait_for_unit("multi-user.target")
+    print(machine.succeed("lsblk"))
 
     # check that os-prober works standalone
-    $machine->succeed("${pkgs.os-prober}/bin/os-prober | grep /dev/vdb1");
+    machine.succeed(
+        "${pkgs.os-prober}/bin/os-prober | grep /dev/vdb1"
+    )
 
     # rebuild and test that debian is available in the grub menu
-    $machine->succeed("nixos-generate-config");
-    $machine->copyFileFromHost(
+    machine.succeed("nixos-generate-config")
+    machine.copy_from_host(
         "${configFile}",
-        "/etc/nixos/configuration.nix");
-    $machine->succeed("nixos-rebuild boot >&2");
+        "/etc/nixos/configuration.nix",
+    )
+    machine.succeed("nixos-rebuild boot >&2")
 
-    $machine->succeed("egrep 'menuentry.*debian' /boot/grub/grub.cfg");
+    machine.succeed("egrep 'menuentry.*debian' /boot/grub/grub.cfg")
   '';
 })
diff --git a/nixos/tests/pinnwand.nix b/nixos/tests/pinnwand.nix
new file mode 100644
index 0000000000000..2204e74b2c286
--- /dev/null
+++ b/nixos/tests/pinnwand.nix
@@ -0,0 +1,86 @@
+import ./make-test-python.nix ({ pkgs, ...}:
+let
+  pythonEnv = pkgs.python3.withPackages (py: with py; [ appdirs toml ]);
+
+  port = 8000;
+  baseUrl = "http://server:${toString port}";
+
+  configureSteck = pkgs.writeScript "configure.py" ''
+    #!${pythonEnv.interpreter}
+    import appdirs
+    import toml
+    import os
+
+    CONFIG = {
+      "base": "${baseUrl}/",
+      "confirm": False,
+      "magic": True,
+      "ignore": True
+    }
+
+    os.makedirs(appdirs.user_config_dir('steck'))
+    with open(os.path.join(appdirs.user_config_dir('steck'), 'steck.toml'), "w") as fd:
+        toml.dump(CONFIG, fd)
+    '';
+in
+{
+  name = "pinnwand";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers =[ hexa ];
+  };
+
+  nodes = {
+    server = { config, ... }:
+    {
+      networking.firewall.allowedTCPPorts = [
+        port
+      ];
+
+      services.pinnwand = {
+        enable = true;
+        port = port;
+      };
+    };
+
+    client = { pkgs, ... }:
+    {
+      environment.systemPackages = [ pkgs.steck ];
+    };
+  };
+
+  testScript = ''
+    start_all()
+
+    server.wait_for_unit("pinnwand.service")
+    client.wait_for_unit("network.target")
+
+    # create steck.toml config file
+    client.succeed("${configureSteck}")
+
+    # wait until the server running pinnwand is reachable
+    client.wait_until_succeeds("ping -c1 server")
+
+    # make sure pinnwand is listening
+    server.wait_until_succeeds("ss -lnp | grep ${toString port}")
+
+    # send the contents of /etc/machine-id
+    response = client.succeed("steck paste /etc/machine-id")
+
+    # parse the steck response
+    raw_url = None
+    removal_link = None
+    for line in response.split("\n"):
+        if line.startswith("View link:"):
+            raw_url = f"${baseUrl}/raw/{line.split('/')[-1]}"
+        if line.startswith("Removal link:"):
+            removal_link = line.split(":", 1)[1]
+
+    # check whether paste matches what we sent
+    client.succeed(f"curl {raw_url} > /tmp/machine-id")
+    client.succeed("diff /tmp/machine-id /etc/machine-id")
+
+    # remove paste and check that it's not available any more
+    client.succeed(f"curl {removal_link}")
+    client.fail(f"curl --fail {raw_url}")
+  '';
+})
diff --git a/nixos/tests/plasma5.nix b/nixos/tests/plasma5.nix
index 2eccfdf47f590..5a603f8cbfb5b 100644
--- a/nixos/tests/plasma5.nix
+++ b/nixos/tests/plasma5.nix
@@ -14,7 +14,7 @@ import ./make-test-python.nix ({ pkgs, ...} :
     services.xserver.displayManager.sddm.enable = true;
     services.xserver.displayManager.defaultSession = "plasma5";
     services.xserver.desktopManager.plasma5.enable = true;
-    services.xserver.displayManager.sddm.autoLogin = {
+    services.xserver.displayManager.autoLogin = {
       enable = true;
       user = "alice";
     };
diff --git a/nixos/tests/podman.nix b/nixos/tests/podman.nix
index 9134a68ff386c..cd8c2b4308c8d 100644
--- a/nixos/tests/podman.nix
+++ b/nixos/tests/podman.nix
@@ -12,9 +12,6 @@ import ./make-test-python.nix (
         { pkgs, ... }:
         {
           virtualisation.podman.enable = true;
-          virtualisation.containers.users = [
-            "alice"
-          ];
 
           users.users.alice = {
             isNormalUser = true;
diff --git a/nixos/tests/postfix-raise-smtpd-tls-security-level.nix b/nixos/tests/postfix-raise-smtpd-tls-security-level.nix
new file mode 100644
index 0000000000000..5fad1fed75b20
--- /dev/null
+++ b/nixos/tests/postfix-raise-smtpd-tls-security-level.nix
@@ -0,0 +1,41 @@
+import ./make-test-python.nix {
+  name = "postfix";
+
+  machine = { pkgs, ... }: {
+    imports = [ common/user-account.nix ];
+    services.postfix = {
+      enable = true;
+      enableSubmissions = true;
+      submissionsOptions = {
+        smtpd_tls_security_level = "none";
+      };
+    };
+
+    environment.systemPackages = let
+      checkConfig = pkgs.writeScriptBin "check-config" ''
+        #!${pkgs.python3.interpreter}
+        import sys
+
+        state = 1
+        success = False
+
+        with open("/etc/postfix/master.cf") as masterCf:
+          for line in masterCf:
+            if state == 1 and line.startswith("submissions"):
+              state = 2
+            elif state == 2 and line.startswith(" ") and "smtpd_tls_security_level=encrypt" in line:
+              success = True
+            elif state == 2 and not line.startswith(" "):
+              state == 3
+        if not success:
+          sys.exit(1)
+      '';
+
+    in [ checkConfig ];
+  };
+
+  testScript = ''
+    machine.wait_for_unit("postfix.service")
+    machine.succeed("check-config")
+  '';
+}
diff --git a/nixos/tests/postfix.nix b/nixos/tests/postfix.nix
new file mode 100644
index 0000000000000..37ae76afec107
--- /dev/null
+++ b/nixos/tests/postfix.nix
@@ -0,0 +1,77 @@
+let
+  certs = import ./common/acme/server/snakeoil-certs.nix;
+  domain = certs.domain;
+in
+import ./make-test-python.nix {
+  name = "postfix";
+
+  machine = { pkgs, ... }: {
+    imports = [ common/user-account.nix ];
+    services.postfix = {
+      enable = true;
+      enableSubmission = true;
+      enableSubmissions = true;
+      sslCACert = certs.ca.cert;
+      sslCert = certs.${domain}.cert;
+      sslKey = certs.${domain}.key;
+      submissionsOptions = {
+          smtpd_sasl_auth_enable = "yes";
+          smtpd_client_restrictions = "permit";
+          milter_macro_daemon_name = "ORIGINATING";
+      };
+    };
+
+    security.pki.certificateFiles = [
+      certs.ca.cert
+    ];
+
+    networking.extraHosts = ''
+      127.0.0.1 ${domain}
+    '';
+
+    environment.systemPackages = let
+      sendTestMail = pkgs.writeScriptBin "send-testmail" ''
+        #!${pkgs.python3.interpreter}
+        import smtplib
+
+        with smtplib.SMTP('${domain}') as smtp:
+          smtp.sendmail('root@localhost', 'alice@localhost', 'Subject: Test\n\nTest data.')
+          smtp.quit()
+      '';
+
+      sendTestMailStarttls = pkgs.writeScriptBin "send-testmail-starttls" ''
+        #!${pkgs.python3.interpreter}
+        import smtplib
+        import ssl
+
+        ctx = ssl.create_default_context()
+
+        with smtplib.SMTP('${domain}') as smtp:
+          smtp.ehlo()
+          smtp.starttls(context=ctx)
+          smtp.ehlo()
+          smtp.sendmail('root@localhost', 'alice@localhost', 'Subject: Test STARTTLS\n\nTest data.')
+          smtp.quit()
+      '';
+
+      sendTestMailSmtps = pkgs.writeScriptBin "send-testmail-smtps" ''
+        #!${pkgs.python3.interpreter}
+        import smtplib
+        import ssl
+
+        ctx = ssl.create_default_context()
+
+        with smtplib.SMTP_SSL(host='${domain}', context=ctx) as smtp:
+          smtp.sendmail('root@localhost', 'alice@localhost', 'Subject: Test SMTPS\n\nTest data.')
+          smtp.quit()
+      '';
+    in [ sendTestMail sendTestMailStarttls sendTestMailSmtps ];
+  };
+
+  testScript = ''
+    machine.wait_for_unit("postfix.service")
+    machine.succeed("send-testmail")
+    machine.succeed("send-testmail-starttls")
+    machine.succeed("send-testmail-smtps")
+  '';
+}
diff --git a/nixos/tests/postgresql-wal-receiver.nix b/nixos/tests/postgresql-wal-receiver.nix
index 372dd9d8c1c11..432b46234f9c1 100644
--- a/nixos/tests/postgresql-wal-receiver.nix
+++ b/nixos/tests/postgresql-wal-receiver.nix
@@ -1,99 +1,111 @@
-{ system ? builtins.currentSystem
-, config ? { }
-, pkgs ? import ../.. { inherit system config; } }:
-
-with import ../lib/testing.nix { inherit system pkgs; };
-with pkgs.lib;
-
 let
-  makePostgresqlWalReceiverTest = subTestName: postgresqlPackage: let
+  # Makes a test for a PostgreSQL package, given by name and looked up from `pkgs`.
+  makePostgresqlWalReceiverTest = postgresqlPackage:
+  {
+    name = postgresqlPackage;
+    value =
+      import ./make-test-python.nix ({ pkgs, lib, ... }: let
 
-  postgresqlDataDir = "/var/db/postgresql/test";
-  replicationUser = "wal_receiver_user";
-  replicationSlot = "wal_receiver_slot";
-  replicationConn = "postgresql://${replicationUser}@localhost";
-  baseBackupDir = "/tmp/pg_basebackup";
-  walBackupDir = "/tmp/pg_wal";
-  atLeast12 = versionAtLeast postgresqlPackage.version "12.0";
-  restoreCommand = ''
-    restore_command = 'cp ${walBackupDir}/%f %p'
-  '';
+        pkg = pkgs."${postgresqlPackage}";
+        postgresqlDataDir = "/var/lib/postgresql/${pkg.psqlSchema}";
+        replicationUser = "wal_receiver_user";
+        replicationSlot = "wal_receiver_slot";
+        replicationConn = "postgresql://${replicationUser}@localhost";
+        baseBackupDir = "/tmp/pg_basebackup";
+        walBackupDir = "/tmp/pg_wal";
+        atLeast12 = lib.versionAtLeast pkg.version "12.0";
 
-  recoveryFile = if atLeast12
-      then pkgs.writeTextDir "recovery.signal" ""
-      else pkgs.writeTextDir "recovery.conf" "${restoreCommand}";
+        recoveryFile = if atLeast12
+            then pkgs.writeTextDir "recovery.signal" ""
+            else pkgs.writeTextDir "recovery.conf" "restore_command = 'cp ${walBackupDir}/%f %p'";
 
-  in makeTest {
-    name = "postgresql-wal-receiver-${subTestName}";
-    meta.maintainers = with maintainers; [ pacien ];
+      in {
+        name = "postgresql-wal-receiver-${postgresqlPackage}";
+        meta.maintainers = with lib.maintainers; [ pacien ];
 
-    machine = { ... }: {
-      services.postgresql = {
-        package = postgresqlPackage;
-        enable = true;
-        dataDir = postgresqlDataDir;
-        extraConfig = ''
-          wal_level = archive # alias for replica on pg >= 9.6
-          max_wal_senders = 10
-          max_replication_slots = 10
-        '' + optionalString atLeast12 ''
-          ${restoreCommand}
-          recovery_end_command = 'touch recovery.done'
-        '';
-        authentication = ''
-          host replication ${replicationUser} all trust
-        '';
-        initialScript = pkgs.writeText "init.sql" ''
-          create user ${replicationUser} replication;
-          select * from pg_create_physical_replication_slot('${replicationSlot}');
-        '';
-      };
+        machine = { ... }: {
+          services.postgresql = {
+            package = pkg;
+            enable = true;
+            settings = lib.mkMerge [
+              {
+                wal_level = "archive"; # alias for replica on pg >= 9.6
+                max_wal_senders = 10;
+                max_replication_slots = 10;
+              }
+              (lib.mkIf atLeast12 {
+                restore_command = "cp ${walBackupDir}/%f %p";
+                recovery_end_command = "touch recovery.done";
+              })
+            ];
+            authentication = ''
+              host replication ${replicationUser} all trust
+            '';
+            initialScript = pkgs.writeText "init.sql" ''
+              create user ${replicationUser} replication;
+              select * from pg_create_physical_replication_slot('${replicationSlot}');
+            '';
+          };
 
-      services.postgresqlWalReceiver.receivers.main = {
-        inherit postgresqlPackage;
-        connection = replicationConn;
-        slot = replicationSlot;
-        directory = walBackupDir;
-      };
-      # This is only to speedup test, it isn't time racing. Service is set to autorestart always,
-      # default 60sec is fine for real system, but is too much for a test
-      systemd.services.postgresql-wal-receiver-main.serviceConfig.RestartSec = mkForce 5;
-    };
+          services.postgresqlWalReceiver.receivers.main = {
+            postgresqlPackage = pkg;
+            connection = replicationConn;
+            slot = replicationSlot;
+            directory = walBackupDir;
+          };
+          # This is only to speedup test, it isn't time racing. Service is set to autorestart always,
+          # default 60sec is fine for real system, but is too much for a test
+          systemd.services.postgresql-wal-receiver-main.serviceConfig.RestartSec = lib.mkForce 5;
+        };
 
-    testScript = ''
-      # make an initial base backup
-      $machine->waitForUnit('postgresql');
-      $machine->waitForUnit('postgresql-wal-receiver-main');
-      # WAL receiver healthchecks PG every 5 seconds, so let's be sure they have connected each other
-      # required only for 9.4
-      $machine->sleep(5);
-      $machine->succeed('${postgresqlPackage}/bin/pg_basebackup --dbname=${replicationConn} --pgdata=${baseBackupDir}');
+        testScript = ''
+          # make an initial base backup
+          machine.wait_for_unit("postgresql")
+          machine.wait_for_unit("postgresql-wal-receiver-main")
+          # WAL receiver healthchecks PG every 5 seconds, so let's be sure they have connected each other
+          # required only for 9.4
+          machine.sleep(5)
+          machine.succeed(
+              "${pkg}/bin/pg_basebackup --dbname=${replicationConn} --pgdata=${baseBackupDir}"
+          )
 
-      # create a dummy table with 100 records
-      $machine->succeed('sudo -u postgres psql --command="create table dummy as select * from generate_series(1, 100) as val;"');
+          # create a dummy table with 100 records
+          machine.succeed(
+              "sudo -u postgres psql --command='create table dummy as select * from generate_series(1, 100) as val;'"
+          )
 
-      # stop postgres and destroy data
-      $machine->systemctl('stop postgresql');
-      $machine->systemctl('stop postgresql-wal-receiver-main');
-      $machine->succeed('rm -r ${postgresqlDataDir}/{base,global,pg_*}');
+          # stop postgres and destroy data
+          machine.systemctl("stop postgresql")
+          machine.systemctl("stop postgresql-wal-receiver-main")
+          machine.succeed("rm -r ${postgresqlDataDir}/{base,global,pg_*}")
 
-      # restore the base backup
-      $machine->succeed('cp -r ${baseBackupDir}/* ${postgresqlDataDir} && chown postgres:postgres -R ${postgresqlDataDir}');
+          # restore the base backup
+          machine.succeed(
+              "cp -r ${baseBackupDir}/* ${postgresqlDataDir} && chown postgres:postgres -R ${postgresqlDataDir}"
+          )
 
-      # prepare WAL and recovery
-      $machine->succeed('chmod a+rX -R ${walBackupDir}');
-      $machine->execute('for part in ${walBackupDir}/*.partial; do mv $part ''${part%%.*}; done'); # make use of partial segments too
-      $machine->succeed('cp ${recoveryFile}/* ${postgresqlDataDir}/ && chmod 666 ${postgresqlDataDir}/recovery*');
+          # prepare WAL and recovery
+          machine.succeed("chmod a+rX -R ${walBackupDir}")
+          machine.execute(
+              "for part in ${walBackupDir}/*.partial; do mv $part ''${part%%.*}; done"
+          )  # make use of partial segments too
+          machine.succeed(
+              "cp ${recoveryFile}/* ${postgresqlDataDir}/ && chmod 666 ${postgresqlDataDir}/recovery*"
+          )
 
-      # replay WAL
-      $machine->systemctl('start postgresql');
-      $machine->waitForFile('${postgresqlDataDir}/recovery.done');
-      $machine->systemctl('restart postgresql');
-      $machine->waitForUnit('postgresql');
+          # replay WAL
+          machine.systemctl("start postgresql")
+          machine.wait_for_file("${postgresqlDataDir}/recovery.done")
+          machine.systemctl("restart postgresql")
+          machine.wait_for_unit("postgresql")
 
-      # check that our records have been restored
-      $machine->succeed('test $(sudo -u postgres psql --pset="pager=off" --tuples-only --command="select count(distinct val) from dummy;") -eq 100');
-    '';
-  };
+          # check that our records have been restored
+          machine.succeed(
+              "test $(sudo -u postgres psql --pset='pager=off' --tuples-only --command='select count(distinct val) from dummy;') -eq 100"
+          )
+        '';
+      });
+    };
 
-in mapAttrs makePostgresqlWalReceiverTest (import ../../pkgs/servers/sql/postgresql pkgs)
+# Maps the generic function over all attributes of PostgreSQL packages
+in builtins.listToAttrs (map makePostgresqlWalReceiverTest (builtins.attrNames (import ../../pkgs/servers/sql/postgresql { })))
diff --git a/nixos/tests/prometheus-exporters.nix b/nixos/tests/prometheus-exporters.nix
index 75c4ca12db24d..fdcc40721324e 100644
--- a/nixos/tests/prometheus-exporters.nix
+++ b/nixos/tests/prometheus-exporters.nix
@@ -22,6 +22,9 @@ let
  *  `metricProvider` (optional)
  *    this attribute contains additional machine config
  *
+ *  `nodeName` (optional)
+ *    override an incompatible testnode name
+ *
  *  Example:
  *    exporterTests.<exporterName> = {
  *      exporterConfig = {
@@ -363,6 +366,31 @@ let
       '';
     };
 
+    modemmanager = {
+      exporterConfig = {
+        enable = true;
+        refreshRate = "10s";
+      };
+      metricProvider = {
+        # ModemManager is installed when NetworkManager is enabled. Ensure it is
+        # started and is wanted by NM and the exporter to start everything up
+        # in the right order.
+        networking.networkmanager.enable = true;
+        systemd.services.ModemManager = {
+          enable = true;
+          wantedBy = [ "NetworkManager.service" "prometheus-modemmanager-exporter.service" ];
+        };
+      };
+      exporterTest = ''
+        wait_for_unit("ModemManager.service")
+        wait_for_unit("prometheus-modemmanager-exporter.service")
+        wait_for_open_port(9539)
+        succeed(
+            "curl -sSf http://localhost:9539/metrics | grep -q 'modemmanager_info'"
+        )
+      '';
+    };
+
     nextcloud = {
       exporterConfig = {
         enable = true;
@@ -565,6 +593,19 @@ let
       '';
     };
 
+    unifi-poller = {
+      nodeName = "unifi_poller";
+      exporterConfig.enable = true;
+      exporterConfig.controllers = [ { } ];
+      exporterTest = ''
+        wait_for_unit("prometheus-unifi-poller-exporter.service")
+        wait_for_open_port(9130)
+        succeed(
+            "curl -sSf localhost:9130/metrics | grep -q 'unifipoller_build_info{.\\+} 1'"
+        )
+      '';
+    };
+
     varnish = {
       exporterConfig = {
         enable = true;
@@ -621,24 +662,27 @@ let
     };
   };
 in
-mapAttrs (exporter: testConfig: (makeTest {
+mapAttrs (exporter: testConfig: (makeTest (let
+  nodeName = testConfig.nodeName or exporter;
+
+in {
   name = "prometheus-${exporter}-exporter";
 
-  nodes.${exporter} = mkMerge [{
+  nodes.${nodeName} = mkMerge [{
     services.prometheus.exporters.${exporter} = testConfig.exporterConfig;
   } testConfig.metricProvider or {}];
 
   testScript = ''
-    ${exporter}.start()
+    ${nodeName}.start()
     ${concatStringsSep "\n" (map (line:
       if (builtins.substring 0 1 line == " " || builtins.substring 0 1 line == ")")
       then line
-      else "${exporter}.${line}"
+      else "${nodeName}.${line}"
     ) (splitString "\n" (removeSuffix "\n" testConfig.exporterTest)))}
-    ${exporter}.shutdown()
+    ${nodeName}.shutdown()
   '';
 
   meta = with maintainers; {
-    maintainers = [ willibutz ];
+    maintainers = [ willibutz elseym ];
   };
-})) exporterTests
+}))) exporterTests
diff --git a/nixos/tests/prometheus.nix b/nixos/tests/prometheus.nix
index bce489168f9ff..af2aa66a55266 100644
--- a/nixos/tests/prometheus.nix
+++ b/nixos/tests/prometheus.nix
@@ -158,7 +158,10 @@ in import ./make-test-python.nix {
 
     s3 = { pkgs, ... } : {
       # Minio requires at least 1GiB of free disk space to run.
-      virtualisation.diskSize = 2 * 1024;
+      virtualisation = {
+        diskSize = 2 * 1024;
+        memorySize = 1024;
+      };
       networking.firewall.allowedTCPPorts = [ minioPort ];
 
       services.minio = {
@@ -235,7 +238,7 @@ in import ./make-test-python.nix {
     # Test if the Thanos bucket command is able to retrieve blocks from the S3 bucket
     # and check if the blocks have the correct labels:
     store.succeed(
-        "thanos bucket ls "
+        "thanos tools bucket ls "
         + "--objstore.config-file=${nodes.store.config.services.thanos.store.objstore.config-file} "
         + "--output=json | "
         + "jq .thanos.labels.some_label | "
diff --git a/nixos/tests/pt2-clone.nix b/nixos/tests/pt2-clone.nix
new file mode 100644
index 0000000000000..b502172e2ee5e
--- /dev/null
+++ b/nixos/tests/pt2-clone.nix
@@ -0,0 +1,35 @@
+import ./make-test-python.nix ({ pkgs, ... }: {
+  name = "pt2-clone";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ fgaz ];
+  };
+
+  machine = { config, pkgs, ... }: {
+    imports = [
+      ./common/x11.nix
+    ];
+
+    services.xserver.enable = true;
+    sound.enable = true;
+    environment.systemPackages = [ pkgs.pt2-clone ];
+  };
+
+  enableOCR = true;
+
+  testScript =
+    ''
+      machine.wait_for_x()
+      # Add a dummy sound card, or the program won't start
+      machine.execute("modprobe snd-dummy")
+
+      machine.execute("pt2-clone &")
+
+      machine.wait_for_window(r"ProTracker")
+      machine.sleep(5)
+      # One of the few words that actually get recognized
+      if "LENGTH" not in machine.get_screen_text():
+          raise Exception("Program did not start successfully")
+      machine.screenshot("screen")
+    '';
+})
+
diff --git a/nixos/tests/radicale.nix b/nixos/tests/radicale.nix
index c81e78a8f9943..1d3679c82a20c 100644
--- a/nixos/tests/radicale.nix
+++ b/nixos/tests/radicale.nix
@@ -14,9 +14,6 @@ let
 
         [storage]
         filesystem_folder = /tmp/collections
-
-        [logging]
-        debug = True
       '';
     };
     # WARNING: DON'T DO THIS IN PRODUCTION!
@@ -49,13 +46,18 @@ in
         services.radicale.extraArgs = [
           "--export-storage" "/tmp/collections-new"
         ];
+        system.stateVersion = "17.03";
       };
       radicale2_verify = lib.recursiveUpdate radicale2 {
-        services.radicale.extraArgs = [ "--verify-storage" ];
+        services.radicale.extraArgs = [ "--debug" "--verify-storage" ];
+        system.stateVersion = "17.09";
       };
       radicale2 = lib.recursiveUpdate (common args) {
         system.stateVersion = "17.09";
       };
+      radicale3 = lib.recursiveUpdate (common args) {
+        system.stateVersion = "20.09";
+      };
     };
 
     # This tests whether the web interface is accessible to an authenticated user
@@ -117,6 +119,22 @@ in
               retcode == 0 and "VCALENDAR" in output
           ), "Could not read calendar from Radicale 2"
 
-      radicale.succeed("curl --fail http://${user}:${password}@localhost:${port}/.web/")
+          radicale.succeed("curl --fail http://${user}:${password}@localhost:${port}/.web/")
+
+      with subtest("Check Radicale 3 functionality"):
+          radicale.succeed(
+              "${switchToConfig "radicale3"} >&2"
+          )
+          radicale.wait_for_unit("radicale.service")
+          radicale.wait_for_open_port(${port})
+
+          (retcode, output) = radicale.execute(
+              "curl --fail http://${user}:${password}@localhost:${port}/someuser/calendar.ics/"
+          )
+          assert (
+              retcode == 0 and "VCALENDAR" in output
+          ), "Could not read calendar from Radicale 3"
+
+          radicale.succeed("curl --fail http://${user}:${password}@localhost:${port}/.web/")
     '';
 })
diff --git a/nixos/tests/restic.nix b/nixos/tests/restic.nix
index 67bb7f1933d66..dad5bdfff27dc 100644
--- a/nixos/tests/restic.nix
+++ b/nixos/tests/restic.nix
@@ -4,33 +4,50 @@ import ./make-test-python.nix (
     let
       password = "some_password";
       repository = "/tmp/restic-backup";
-      passwordFile = pkgs.writeText "password" "correcthorsebatterystaple";
+      rcloneRepository = "rclone:local:/tmp/restic-rclone-backup";
+
+      passwordFile = "${pkgs.writeText "password" "correcthorsebatterystaple"}";
+      initialize = true;
+      paths = [ "/opt" ];
+      pruneOpts = [
+        "--keep-daily 2"
+        "--keep-weekly 1"
+        "--keep-monthly 1"
+        "--keep-yearly 99"
+      ];
     in
       {
         name = "restic";
 
         meta = with pkgs.stdenv.lib.maintainers; {
-          maintainers = [ bbigras ];
+          maintainers = [ bbigras i077 ];
         };
 
         nodes = {
           server =
-            { ... }:
+            { pkgs, ... }:
               {
                 services.restic.backups = {
                   remotebackup = {
-                    inherit repository;
-                    passwordFile = "${passwordFile}";
-                    initialize = true;
-                    paths = [ "/opt" ];
-                    pruneOpts = [
-                      "--keep-daily 2"
-                      "--keep-weekly 1"
-                      "--keep-monthly 1"
-                      "--keep-yearly 99"
-                    ];
+                    inherit repository passwordFile initialize paths pruneOpts;
+                  };
+                  rclonebackup = {
+                    repository = rcloneRepository;
+                    rcloneConfig = {
+                      type = "local";
+                      one_file_system = true;
+                    };
+
+                    # This gets overridden by rcloneConfig.type
+                    rcloneConfigFile = pkgs.writeText "rclone.conf" ''
+                      [local]
+                      type=ftp
+                    '';
+                    inherit passwordFile initialize paths pruneOpts;
                   };
                 };
+
+                environment.sessionVariables.RCLONE_CONFIG_LOCAL_TYPE = "local";
               };
         };
 
@@ -38,25 +55,35 @@ import ./make-test-python.nix (
           server.start()
           server.wait_for_unit("dbus.socket")
           server.fail(
-              "${pkgs.restic}/bin/restic -r ${repository} -p ${passwordFile} snapshots"
+              "${pkgs.restic}/bin/restic -r ${repository} -p ${passwordFile} snapshots",
+              "${pkgs.restic}/bin/restic -r ${rcloneRepository} -p ${passwordFile} snapshots",
           )
           server.succeed(
               "mkdir -p /opt",
               "touch /opt/some_file",
+              "mkdir -p /tmp/restic-rclone-backup",
               "timedatectl set-time '2016-12-13 13:45'",
               "systemctl start restic-backups-remotebackup.service",
+              "systemctl start restic-backups-rclonebackup.service",
               '${pkgs.restic}/bin/restic -r ${repository} -p ${passwordFile} snapshots -c | grep -e "^1 snapshot"',
+              '${pkgs.restic}/bin/restic -r ${rcloneRepository} -p ${passwordFile} snapshots -c | grep -e "^1 snapshot"',
               "timedatectl set-time '2017-12-13 13:45'",
               "systemctl start restic-backups-remotebackup.service",
+              "systemctl start restic-backups-rclonebackup.service",
               "timedatectl set-time '2018-12-13 13:45'",
               "systemctl start restic-backups-remotebackup.service",
+              "systemctl start restic-backups-rclonebackup.service",
               "timedatectl set-time '2018-12-14 13:45'",
               "systemctl start restic-backups-remotebackup.service",
+              "systemctl start restic-backups-rclonebackup.service",
               "timedatectl set-time '2018-12-15 13:45'",
               "systemctl start restic-backups-remotebackup.service",
+              "systemctl start restic-backups-rclonebackup.service",
               "timedatectl set-time '2018-12-16 13:45'",
               "systemctl start restic-backups-remotebackup.service",
+              "systemctl start restic-backups-rclonebackup.service",
               '${pkgs.restic}/bin/restic -r ${repository} -p ${passwordFile} snapshots -c | grep -e "^4 snapshot"',
+              '${pkgs.restic}/bin/restic -r ${rcloneRepository} -p ${passwordFile} snapshots -c | grep -e "^4 snapshot"',
           )
         '';
       }
diff --git a/nixos/tests/robustirc-bridge.nix b/nixos/tests/robustirc-bridge.nix
new file mode 100644
index 0000000000000..a5c22d73a34f3
--- /dev/null
+++ b/nixos/tests/robustirc-bridge.nix
@@ -0,0 +1,29 @@
+import ./make-test-python.nix ({ pkgs, ... }:
+
+{
+  name = "robustirc-bridge";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ hax404 ];
+  };
+
+  nodes =
+    { bridge =
+      { services.robustirc-bridge = {
+          enable = true;
+          extraFlags = [
+            "-listen localhost:6667"
+            "-network example.com"
+          ];
+        };
+      };
+    };
+
+    testScript =
+    ''
+      start_all()
+
+      bridge.wait_for_unit("robustirc-bridge.service")
+      bridge.wait_for_open_port(1080)
+      bridge.wait_for_open_port(6667)
+    '';
+})
diff --git a/nixos/tests/sddm.nix b/nixos/tests/sddm.nix
index a145705250f71..f9b961163c3c1 100644
--- a/nixos/tests/sddm.nix
+++ b/nixos/tests/sddm.nix
@@ -44,8 +44,8 @@ let
       machine = { ... }: {
         imports = [ ./common/user-account.nix ];
         services.xserver.enable = true;
-        services.xserver.displayManager.sddm = {
-          enable = true;
+        services.xserver.displayManager = {
+          sddm.enable = true;
           autoLogin = {
             enable = true;
             user = "alice";
diff --git a/nixos/tests/shadowsocks/common.nix b/nixos/tests/shadowsocks/common.nix
new file mode 100644
index 0000000000000..8cbbc3f206848
--- /dev/null
+++ b/nixos/tests/shadowsocks/common.nix
@@ -0,0 +1,84 @@
+{ name
+, plugin ? null
+, pluginOpts ? ""
+}:
+
+import ../make-test-python.nix ({ pkgs, lib, ... }: {
+    inherit name;
+    meta = {
+      maintainers = with lib.maintainers; [ hmenke ];
+    };
+
+    nodes = {
+      server = {
+        boot.kernel.sysctl."net.ipv4.ip_forward" = "1";
+        networking.useDHCP = false;
+        networking.interfaces.eth1.ipv4.addresses = [
+          { address = "192.168.0.1"; prefixLength = 24; }
+        ];
+        networking.firewall.rejectPackets = true;
+        networking.firewall.allowedTCPPorts = [ 8488 ];
+        networking.firewall.allowedUDPPorts = [ 8488 ];
+        services.shadowsocks = {
+          enable = true;
+          encryptionMethod = "chacha20-ietf-poly1305";
+          password = "pa$$w0rd";
+          localAddress = [ "0.0.0.0" ];
+          port = 8488;
+          fastOpen = false;
+          mode = "tcp_and_udp";
+        } // lib.optionalAttrs (plugin != null) {
+          inherit plugin;
+          pluginOpts = "server;${pluginOpts}";
+        };
+        services.nginx = {
+          enable = true;
+          virtualHosts.server = {
+            locations."/".root = pkgs.writeTextDir "index.html" "It works!";
+          };
+        };
+      };
+
+      client = {
+        networking.useDHCP = false;
+        networking.interfaces.eth1.ipv4.addresses = [
+          { address = "192.168.0.2"; prefixLength = 24; }
+        ];
+        systemd.services.shadowsocks-client = {
+          description = "connect to shadowsocks";
+          after = [ "network.target" ];
+          wantedBy = [ "multi-user.target" ];
+          path = with pkgs; [ shadowsocks-libev ];
+          script = ''
+            exec ss-local \
+                -s 192.168.0.1 \
+                -p 8488 \
+                -l 1080 \
+                -k 'pa$$w0rd' \
+                -m chacha20-ietf-poly1305 \
+                -a nobody \
+                ${lib.optionalString (plugin != null) ''
+                  --plugin "${plugin}" --plugin-opts "${pluginOpts}"
+                ''}
+          '';
+        };
+      };
+    };
+
+    testScript = ''
+      start_all()
+
+      server.wait_for_unit("shadowsocks-libev.service")
+      client.wait_for_unit("shadowsocks-client.service")
+
+      client.fail(
+          "${pkgs.curl}/bin/curl 192.168.0.1:80"
+      )
+
+      msg = client.succeed(
+          "${pkgs.curl}/bin/curl --socks5 localhost:1080 192.168.0.1:80"
+      )
+      assert msg == "It works!", "Could not connect through shadowsocks"
+    '';
+  }
+)
diff --git a/nixos/tests/shadowsocks/default.nix b/nixos/tests/shadowsocks/default.nix
new file mode 100644
index 0000000000000..37a8c3c9d0d3b
--- /dev/null
+++ b/nixos/tests/shadowsocks/default.nix
@@ -0,0 +1,16 @@
+{ system ? builtins.currentSystem
+, config ? { }
+, pkgs ? import ../../.. { inherit system config; }
+}:
+
+{
+  "basic" = import ./common.nix {
+    name = "basic";
+  };
+
+  "v2ray-plugin" = import ./common.nix {
+    name = "v2ray-plugin";
+    plugin = "${pkgs.shadowsocks-v2ray-plugin}/bin/v2ray-plugin";
+    pluginOpts = "host=nixos.org";
+  };
+}
diff --git a/nixos/tests/shattered-pixel-dungeon.nix b/nixos/tests/shattered-pixel-dungeon.nix
new file mode 100644
index 0000000000000..cf6ee8db80b22
--- /dev/null
+++ b/nixos/tests/shattered-pixel-dungeon.nix
@@ -0,0 +1,29 @@
+import ./make-test-python.nix ({ pkgs, ... }: {
+  name = "shattered-pixel-dungeon";
+  meta = with pkgs.lib.maintainers; {
+    maintainers = [ fgaz ];
+  };
+
+  machine = { config, pkgs, ... }: {
+    imports = [
+      ./common/x11.nix
+    ];
+
+    services.xserver.enable = true;
+    environment.systemPackages = [ pkgs.shattered-pixel-dungeon ];
+  };
+
+  enableOCR = true;
+
+  testScript =
+    ''
+      machine.wait_for_x()
+      machine.execute("shattered-pixel-dungeon &")
+      machine.wait_for_window(r"Shattered Pixel Dungeon")
+      machine.sleep(5)
+      if "Enter" not in machine.get_screen_text():
+          raise Exception("Program did not start successfully")
+      machine.screenshot("screen")
+    '';
+})
+
diff --git a/nixos/tests/slurm.nix b/nixos/tests/slurm.nix
index d0e62d15437c0..a54c5d9db4826 100644
--- a/nixos/tests/slurm.nix
+++ b/nixos/tests/slurm.nix
@@ -1,16 +1,52 @@
-import ./make-test-python.nix ({ lib, ... }:
+import ./make-test-python.nix ({ lib, pkgs, ... }:
 let
-    mungekey = "mungeverryweakkeybuteasytointegratoinatest";
-
     slurmconfig = {
-      controlMachine = "control";
-      nodeName = [ "node[1-3] CPUs=1 State=UNKNOWN" ];
-      partitionName = [ "debug Nodes=node[1-3] Default=YES MaxTime=INFINITE State=UP" ];
-      extraConfig = ''
-        AccountingStorageHost=dbd
-        AccountingStorageType=accounting_storage/slurmdbd
-      '';
+      services.slurm = {
+        controlMachine = "control";
+        nodeName = [ "node[1-3] CPUs=1 State=UNKNOWN" ];
+        partitionName = [ "debug Nodes=node[1-3] Default=YES MaxTime=INFINITE State=UP" ];
+        extraConfig = ''
+          AccountingStorageHost=dbd
+          AccountingStorageType=accounting_storage/slurmdbd
+        '';
+      };
+      environment.systemPackages = [ mpitest ];
+      networking.firewall.enable = false;
+      systemd.tmpfiles.rules = [
+        "f /etc/munge/munge.key 0400 munge munge - mungeverryweakkeybuteasytointegratoinatest"
+      ];
     };
+
+    mpitest = let
+      mpitestC = pkgs.writeText "mpitest.c" ''
+        #include <stdio.h>
+        #include <stdlib.h>
+        #include <mpi.h>
+
+        int
+        main (int argc, char *argv[])
+        {
+          int rank, size, length;
+          char name[512];
+
+          MPI_Init (&argc, &argv);
+          MPI_Comm_rank (MPI_COMM_WORLD, &rank);
+          MPI_Comm_size (MPI_COMM_WORLD, &size);
+          MPI_Get_processor_name (name, &length);
+
+          if ( rank == 0 ) printf("size=%d\n", size);
+
+          printf ("%s: hello world from process %d of %d\n", name, rank, size);
+
+          MPI_Finalize ();
+
+          return EXIT_SUCCESS;
+        }
+      '';
+    in pkgs.runCommandNoCC "mpitest" {} ''
+      mkdir -p $out/bin
+      ${pkgs.openmpi}/bin/mpicc ${mpitestC} -o $out/bin/mpitest
+    '';
 in {
   name = "slurm";
 
@@ -21,37 +57,40 @@ in {
     computeNode =
       { ...}:
       {
+        imports = [ slurmconfig ];
         # TODO slurmd port and slurmctld port should be configurations and
         # automatically allowed by the  firewall.
-        networking.firewall.enable = false;
         services.slurm = {
           client.enable = true;
-        } // slurmconfig;
+        };
       };
     in {
 
     control =
       { ...}:
       {
-        networking.firewall.enable = false;
+        imports = [ slurmconfig ];
         services.slurm = {
           server.enable = true;
-        } // slurmconfig;
+        };
       };
 
     submit =
       { ...}:
       {
-        networking.firewall.enable = false;
+        imports = [ slurmconfig ];
         services.slurm = {
           enableStools = true;
-        } // slurmconfig;
+        };
       };
 
     dbd =
       { pkgs, ... } :
       {
         networking.firewall.enable = false;
+        systemd.tmpfiles.rules = [
+          "f /etc/munge/munge.key 0400 munge munge - mungeverryweakkeybuteasytointegratoinatest"
+        ];
         services.slurm.dbdserver = {
           enable = true;
           storagePass = "password123";
@@ -87,24 +126,7 @@ in {
   ''
   start_all()
 
-  # Set up authentification across the cluster
-  for node in [submit, control, dbd, node1, node2, node3]:
-
-      node.wait_for_unit("default.target")
-
-      node.succeed("mkdir /etc/munge")
-      node.succeed(
-          "echo '${mungekey}' > /etc/munge/munge.key"
-      )
-      node.succeed("chmod 0400 /etc/munge/munge.key")
-      node.succeed("chown munge:munge /etc/munge/munge.key")
-      node.succeed("systemctl restart munged")
-
-      node.wait_for_unit("munged")
-
-
-  # Restart the services since they have probably failed due to the munge init
-  # failure
+  # Make sure DBD is up after DB initialzation
   with subtest("can_start_slurmdbd"):
       dbd.succeed("systemctl restart slurmdbd")
       dbd.wait_for_unit("slurmdbd.service")
@@ -137,5 +159,8 @@ in {
           # find the srun job from above in the database
           control.succeed("sleep 5")
           control.succeed("sacct | grep hostname")
+
+  with subtest("run_PMIx_mpitest"):
+      submit.succeed("srun -N 3 --mpi=pmix mpitest | grep size=3")
   '';
 })
diff --git a/nixos/tests/snapcast.nix b/nixos/tests/snapcast.nix
new file mode 100644
index 0000000000000..92534f1028190
--- /dev/null
+++ b/nixos/tests/snapcast.nix
@@ -0,0 +1,58 @@
+import ./make-test-python.nix ({ pkgs, ...} :
+
+let
+  port = 10004;
+  tcpPort = 10005;
+  httpPort = 10080;
+in {
+  name = "snapcast";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ hexa ];
+  };
+
+  nodes = {
+    server = {
+      services.snapserver = {
+        enable = true;
+        port = port;
+        tcp.port = tcpPort;
+        http.port = httpPort;
+        streams = {
+          mpd = {
+            type = "pipe";
+            location = "/run/snapserver/mpd";
+          };
+          bluetooth = {
+            type = "pipe";
+            location = "/run/snapserver/bluetooth";
+          };
+        };
+      };
+    };
+  };
+
+  testScript = ''
+    import json
+
+    get_rpc_version = {"id": "1", "jsonrpc": "2.0", "method": "Server.GetRPCVersion"}
+
+    start_all()
+
+    server.wait_for_unit("snapserver.service")
+    server.wait_until_succeeds("ss -ntl | grep -q ${toString port}")
+    server.wait_until_succeeds("ss -ntl | grep -q ${toString tcpPort}")
+    server.wait_until_succeeds("ss -ntl | grep -q ${toString httpPort}")
+
+    with subtest("check that pipes are created"):
+        server.succeed("test -p /run/snapserver/mpd")
+        server.succeed("test -p /run/snapserver/bluetooth")
+
+    with subtest("test tcp json-rpc"):
+        server.succeed(f"echo '{json.dumps(get_rpc_version)}' | nc -w 1 localhost ${toString tcpPort}")
+
+    with subtest("test http json-rpc"):
+        server.succeed(
+            "curl --fail http://localhost:${toString httpPort}/jsonrpc -d '{json.dumps(get_rpc_version)}'"
+        )
+  '';
+})
diff --git a/nixos/tests/sslh.nix b/nixos/tests/sslh.nix
new file mode 100644
index 0000000000000..2a800aa52d0aa
--- /dev/null
+++ b/nixos/tests/sslh.nix
@@ -0,0 +1,83 @@
+import ./make-test-python.nix {
+  name = "sslh";
+
+  nodes = {
+    server = { pkgs, lib, ... }: {
+      networking.firewall.allowedTCPPorts = [ 443 ];
+      networking.interfaces.eth1.ipv6.addresses = [
+        {
+          address = "fe00:aa:bb:cc::2";
+          prefixLength = 64;
+        }
+      ];
+      # sslh is really slow when reverse dns does not work
+      networking.hosts = {
+        "fe00:aa:bb:cc::2" = [ "server" ];
+        "fe00:aa:bb:cc::1" = [ "client" ];
+      };
+      services.sslh = {
+        enable = true;
+        transparent = true;
+        appendConfig = ''
+          protocols:
+          (
+            { name: "ssh"; service: "ssh"; host: "localhost"; port: "22"; probe: "builtin"; },
+            { name: "http"; host: "localhost"; port: "80"; probe: "builtin"; },
+          );
+        '';
+      };
+      services.openssh.enable = true;
+      users.users.root.openssh.authorizedKeys.keyFiles = [ ./initrd-network-ssh/id_ed25519.pub ];
+      services.nginx = {
+        enable = true;
+        virtualHosts."localhost" = {
+          addSSL = false;
+          default = true;
+          root = pkgs.runCommand "testdir" {} ''
+            mkdir "$out"
+            echo hello world > "$out/index.html"
+          '';
+        };
+      };
+    };
+    client = { ... }: {
+      networking.interfaces.eth1.ipv6.addresses = [
+        {
+          address = "fe00:aa:bb:cc::1";
+          prefixLength = 64;
+        }
+      ];
+      networking.hosts."fe00:aa:bb:cc::2" = [ "server" ];
+      environment.etc.sshKey = {
+        source = ./initrd-network-ssh/id_ed25519; # dont use this anywhere else
+        mode = "0600";
+      };
+    };
+  };
+
+  testScript = ''
+    start_all()
+
+    server.wait_for_unit("sslh.service")
+    server.wait_for_unit("nginx.service")
+    server.wait_for_unit("sshd.service")
+    server.wait_for_open_port(80)
+    server.wait_for_open_port(443)
+    server.wait_for_open_port(22)
+
+    for arg in ["-6", "-4"]:
+        client.wait_until_succeeds(f"ping {arg} -c1 server")
+
+        # check that ssh through sslh works
+        client.succeed(
+            f"ssh {arg} -p 443 -i /etc/sshKey -o StrictHostKeyChecking=accept-new server 'echo $SSH_CONNECTION > /tmp/foo{arg}'"
+        )
+
+        # check that 1/ the above ssh command had an effect 2/ transparent proxying really works
+        ip = "fe00:aa:bb:cc::1" if arg == "-6" else "192.168.1."
+        server.succeed(f"grep '{ip}' /tmp/foo{arg}")
+
+        # check that http through sslh works
+        assert client.succeed(f"curl {arg} http://server:443").strip() == "hello world"
+  '';
+}
diff --git a/nixos/tests/sssd-ldap.nix b/nixos/tests/sssd-ldap.nix
new file mode 100644
index 0000000000000..b68403a0102a8
--- /dev/null
+++ b/nixos/tests/sssd-ldap.nix
@@ -0,0 +1,78 @@
+import ./make-test-python.nix ({ pkgs, ... }:
+  let
+    dbDomain = "example.org";
+    dbSuffix = "dc=example,dc=org";
+
+    ldapRootUser = "admin";
+    ldapRootPassword = "foobar";
+
+    testUser = "alice";
+  in
+  {
+    name = "sssd-ldap";
+
+    meta = with pkgs.stdenv.lib.maintainers; {
+      maintainers = [ bbigras ];
+    };
+
+    machine = { pkgs, ... }: {
+      services.openldap = {
+        enable = true;
+        rootdn = "cn=${ldapRootUser},${dbSuffix}";
+        rootpw = ldapRootPassword;
+        suffix = dbSuffix;
+        declarativeContents = ''
+          dn: ${dbSuffix}
+          objectClass: top
+          objectClass: dcObject
+          objectClass: organization
+          o: ${dbDomain}
+
+          dn: ou=posix,${dbSuffix}
+          objectClass: top
+          objectClass: organizationalUnit
+
+          dn: ou=accounts,ou=posix,${dbSuffix}
+          objectClass: top
+          objectClass: organizationalUnit
+
+          dn: uid=${testUser},ou=accounts,ou=posix,${dbSuffix}
+          objectClass: person
+          objectClass: posixAccount
+          # userPassword: somePasswordHash
+          homeDirectory: /home/${testUser}
+          uidNumber: 1234
+          gidNumber: 1234
+          cn: ""
+          sn: ""
+        '';
+      };
+
+      services.sssd = {
+        enable = true;
+        config = ''
+          [sssd]
+          config_file_version = 2
+          services = nss, pam, sudo
+          domains = ${dbDomain}
+
+          [domain/${dbDomain}]
+          auth_provider = ldap
+          id_provider = ldap
+          ldap_uri = ldap://127.0.0.1:389
+          ldap_search_base = ${dbSuffix}
+          ldap_default_bind_dn = cn=${ldapRootUser},${dbSuffix}
+          ldap_default_authtok_type = password
+          ldap_default_authtok = ${ldapRootPassword}
+        '';
+      };
+    };
+
+    testScript = ''
+      machine.start()
+      machine.wait_for_unit("openldap.service")
+      machine.wait_for_unit("sssd.service")
+      machine.succeed("getent passwd ${testUser}")
+    '';
+  }
+)
diff --git a/nixos/tests/sssd.nix b/nixos/tests/sssd.nix
new file mode 100644
index 0000000000000..4c6ca86c74c8f
--- /dev/null
+++ b/nixos/tests/sssd.nix
@@ -0,0 +1,17 @@
+import ./make-test-python.nix ({ pkgs, ... }:
+
+{
+  name = "sssd";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ bbigras ];
+  };
+  machine = { pkgs, ... }: {
+    services.sssd.enable = true;
+  };
+
+  testScript = ''
+      start_all()
+      machine.wait_for_unit("multi-user.target")
+      machine.wait_for_unit("sssd.service")
+    '';
+})
diff --git a/nixos/tests/sudo.nix b/nixos/tests/sudo.nix
index 5bbec3d572691..8c38f1b47ef0c 100644
--- a/nixos/tests/sudo.nix
+++ b/nixos/tests/sudo.nix
@@ -74,7 +74,7 @@ in
         with subtest("test5 user should not be able to run commands under root"):
             machine.fail("sudo -u test5 sudo -n -u root true")
 
-        with subtest("test5 user should be able to keep his environment"):
+        with subtest("test5 user should be able to keep their environment"):
             machine.succeed("sudo -u test5 sudo -n -E -u test1 true")
 
         with subtest("users in group 'barfoo' should not be able to keep their environment"):
diff --git a/nixos/tests/syncthing-init.nix b/nixos/tests/syncthing-init.nix
index 9c8e0a3d087ef..0a01da52b68bc 100644
--- a/nixos/tests/syncthing-init.nix
+++ b/nixos/tests/syncthing-init.nix
@@ -24,9 +24,8 @@ in {
   testScript = ''
     machine.wait_for_unit("syncthing-init.service")
     config = machine.succeed("cat /var/lib/syncthing/.config/syncthing/config.xml")
-   
+
     assert "testFolder" in config
     assert "${testId}" in config
   '';
 })
-
diff --git a/nixos/tests/syncthing.nix b/nixos/tests/syncthing.nix
new file mode 100644
index 0000000000000..9e2a8e01e3fb8
--- /dev/null
+++ b/nixos/tests/syncthing.nix
@@ -0,0 +1,65 @@
+import ./make-test-python.nix ({ lib, pkgs, ... }: {
+  name = "syncthing";
+  meta.maintainers = with pkgs.stdenv.lib.maintainers; [ chkno ];
+
+  nodes = rec {
+    a = {
+      environment.systemPackages = with pkgs; [ curl libxml2 syncthing ];
+      services.syncthing = {
+        enable = true;
+        openDefaultPorts = true;
+      };
+    };
+    b = a;
+  };
+
+  testScript = ''
+    import json
+    import shlex
+
+    confdir = "/var/lib/syncthing/.config/syncthing"
+
+
+    def addPeer(host, name, deviceID):
+        APIKey = host.succeed(
+            "xmllint --xpath 'string(configuration/gui/apikey)' %s/config.xml" % confdir
+        ).strip()
+        oldConf = host.succeed(
+            "curl -Ss -H 'X-API-Key: %s' 127.0.0.1:8384/rest/system/config" % APIKey
+        )
+        conf = json.loads(oldConf)
+        conf["devices"].append({"deviceID": deviceID, "id": name})
+        conf["folders"].append(
+            {
+                "devices": [{"deviceID": deviceID}],
+                "id": "foo",
+                "path": "/var/lib/syncthing/foo",
+                "rescanIntervalS": 1,
+            }
+        )
+        newConf = json.dumps(conf)
+        host.succeed(
+            "curl -Ss -H 'X-API-Key: %s' 127.0.0.1:8384/rest/system/config -d %s"
+            % (APIKey, shlex.quote(newConf))
+        )
+
+
+    start_all()
+    a.wait_for_unit("syncthing.service")
+    b.wait_for_unit("syncthing.service")
+    a.wait_for_open_port(22000)
+    b.wait_for_open_port(22000)
+
+    aDeviceID = a.succeed("syncthing -home=%s -device-id" % confdir).strip()
+    bDeviceID = b.succeed("syncthing -home=%s -device-id" % confdir).strip()
+    addPeer(a, "b", bDeviceID)
+    addPeer(b, "a", aDeviceID)
+
+    a.wait_for_file("/var/lib/syncthing/foo")
+    b.wait_for_file("/var/lib/syncthing/foo")
+    a.succeed("echo a2b > /var/lib/syncthing/foo/a2b")
+    b.succeed("echo b2a > /var/lib/syncthing/foo/b2a")
+    a.wait_for_file("/var/lib/syncthing/foo/b2a")
+    b.wait_for_file("/var/lib/syncthing/foo/a2b")
+  '';
+})
diff --git a/nixos/tests/systemd-boot.nix b/nixos/tests/systemd-boot.nix
index eba4729d6de84..7a663dd9b4284 100644
--- a/nixos/tests/systemd-boot.nix
+++ b/nixos/tests/systemd-boot.nix
@@ -11,6 +11,8 @@ let
     virtualisation.useBootLoader = true;
     virtualisation.useEFIBoot = true;
     boot.loader.systemd-boot.enable = true;
+    boot.loader.efi.canTouchEfiVariables = true;
+    environment.systemPackages = [ pkgs.efibootmgr ];
   };
 in
 {
@@ -31,6 +33,36 @@ in
       machine.succeed(
           "test -e /sys/firmware/efi/efivars/LoaderEntrySelected-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f"
       )
+
+      # "bootctl install" should have created an EFI entry
+      machine.succeed('efibootmgr | grep "Linux Boot Manager"')
+    '';
+  };
+
+  # Boot without having created an EFI entry--instead using default "/EFI/BOOT/BOOTX64.EFI"
+  fallback = makeTest {
+    name = "systemd-boot-fallback";
+    meta.maintainers = with pkgs.stdenv.lib.maintainers; [ danielfullmer ];
+
+    machine = { pkgs, lib, ... }: {
+      imports = [ common ];
+      boot.loader.efi.canTouchEfiVariables = mkForce false;
+    };
+
+    testScript = ''
+      machine.start()
+      machine.wait_for_unit("multi-user.target")
+
+      machine.succeed("test -e /boot/loader/entries/nixos-generation-1.conf")
+
+      # Ensure we actually booted using systemd-boot
+      # Magic number is the vendor UUID used by systemd-boot.
+      machine.succeed(
+          "test -e /sys/firmware/efi/efivars/LoaderEntrySelected-4a67b082-0a4c-41cf-b6c7-440b29bb8c4f"
+      )
+
+      # "bootctl install" should _not_ have created an EFI entry
+      machine.fail('efibootmgr | grep "Linux Boot Manager"')
     '';
   };
 
diff --git a/nixos/tests/systemd-networkd-ipv6-prefix-delegation.nix b/nixos/tests/systemd-networkd-ipv6-prefix-delegation.nix
index 99cd341eec15e..99395fe3023f3 100644
--- a/nixos/tests/systemd-networkd-ipv6-prefix-delegation.nix
+++ b/nixos/tests/systemd-networkd-ipv6-prefix-delegation.nix
@@ -31,7 +31,7 @@ import ./make-test-python.nix ({pkgs, ...}: {
         firewall.enable = false;
         interfaces.eth1.ipv4.addresses = lib.mkForce []; # no need for legacy IP
         interfaces.eth1.ipv6.addresses = lib.mkForce [
-          { address = "2001:DB8::"; prefixLength = 64; }
+          { address = "2001:DB8::1"; prefixLength = 64; }
         ];
       };
 
@@ -260,7 +260,7 @@ import ./make-test-python.nix ({pkgs, ...}: {
     client.wait_until_succeeds("ping -6 -c 1 FD42::1")
 
     # the global IP of the ISP router should still not be a reachable
-    router.fail("ping -6 -c 1 2001:DB8::")
+    router.fail("ping -6 -c 1 2001:DB8::1")
 
     # Once we have internal connectivity boot up the ISP
     isp.start()
@@ -273,11 +273,11 @@ import ./make-test-python.nix ({pkgs, ...}: {
 
     # wait until the uplink interface has a good status
     router.wait_for_unit("network-online.target")
-    router.wait_until_succeeds("ping -6 -c1 2001:DB8::")
+    router.wait_until_succeeds("ping -6 -c1 2001:DB8::1")
 
     # shortly after that the client should have received it's global IPv6
     # address and thus be able to ping the ISP
-    client.wait_until_succeeds("ping -6 -c1 2001:DB8::")
+    client.wait_until_succeeds("ping -6 -c1 2001:DB8::1")
 
     # verify that we got a globally scoped address in eth1 from the
     # documentation prefix
diff --git a/nixos/tests/systemd-networkd-vrf.nix b/nixos/tests/systemd-networkd-vrf.nix
index af7813a2e604a..bd4751f8e4359 100644
--- a/nixos/tests/systemd-networkd-vrf.nix
+++ b/nixos/tests/systemd-networkd-vrf.nix
@@ -159,6 +159,8 @@ in {
     node2.wait_for_unit("network.target")
     node3.wait_for_unit("network.target")
 
+    # NOTE: please keep in mind that the trailing whitespaces in the following strings
+    # are intentional as the output is compared against the raw `iproute2`-output.
     client_ipv4_table = """
     192.168.1.2 dev vrf1 proto static metric 100 
     192.168.2.3 dev vrf2 proto static metric 100
@@ -194,18 +196,16 @@ in {
         client.succeed("ping -c5 192.168.1.2")
         client.succeed("ping -c5 192.168.2.3")
 
-    # Test whether SSH through a VRF IP is possible.
-    # (Note: this seems to be an issue on Linux 5.x, so I decided to add this to
-    # ensure that we catch this when updating the default kernel).
-    # with subtest("tcp traffic through vrf works"):
-    #     node1.wait_for_open_port(22)
-    #     client.succeed(
-    #         "cat ${snakeOilPrivateKey} > privkey.snakeoil"
-    #     )
-    #     client.succeed("chmod 600 privkey.snakeoil")
-    #     client.succeed(
-    #         "ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i privkey.snakeoil root@192.168.1.2 true"
-    #     )
+    # Test whether TCP through a VRF IP is possible.
+    with subtest("tcp traffic through vrf works"):
+        node1.wait_for_open_port(22)
+        client.succeed(
+            "cat ${snakeOilPrivateKey} > privkey.snakeoil"
+        )
+        client.succeed("chmod 600 privkey.snakeoil")
+        client.succeed(
+            "ulimit -l 2048; ip vrf exec vrf1 ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -i privkey.snakeoil root@192.168.1.2 true"
+        )
 
     # Only configured routes through the VRF from the main routing table should
     # work. Additional IPs are only reachable when binding to the vrf interface.
diff --git a/nixos/tests/systemd-networkd.nix b/nixos/tests/systemd-networkd.nix
index 319e5e94eceb1..d5fb2431dbad5 100644
--- a/nixos/tests/systemd-networkd.nix
+++ b/nixos/tests/systemd-networkd.nix
@@ -7,18 +7,19 @@ let generateNodeConf = { lib, pkgs, config, privk, pubk, peerId, nodeId, ...}: {
       virtualisation.vlans = [ 1 ];
       environment.systemPackages = with pkgs; [ wireguard-tools ];
       boot.extraModulePackages = [ config.boot.kernelPackages.wireguard ];
-      systemd.tmpfiles.rules = [
-        "f /run/wg_priv 0640 root systemd-network - ${privk}"
-      ];
       systemd.network = {
         enable = true;
         netdevs = {
           "90-wg0" = {
             netdevConfig = { Kind = "wireguard"; Name = "wg0"; };
             wireguardConfig = {
-              PrivateKeyFile = "/run/wg_priv";
+              # NOTE: we're storing the wireguard private key in the
+              #       store for this test. Do not do this in the real
+              #       world. Keep in mind the nix store is
+              #       world-readable.
+              PrivateKeyFile = pkgs.writeText "wg0-priv" privk;
               ListenPort = 51820;
-              FwMark = 42;
+              FirewallMark = 42;
             };
             wireguardPeers = [ {wireguardPeerConfig={
               Endpoint = "192.168.1.${peerId}:51820";
diff --git a/nixos/tests/systemd.nix b/nixos/tests/systemd.nix
index ca2e36a443e99..dfa16eecfad21 100644
--- a/nixos/tests/systemd.nix
+++ b/nixos/tests/systemd.nix
@@ -4,7 +4,10 @@ import ./make-test-python.nix ({ pkgs, ... }: {
   machine = { lib, ... }: {
     imports = [ common/user-account.nix common/x11.nix ];
 
-    virtualisation.emptyDiskImages = [ 512 ];
+    virtualisation.emptyDiskImages = [ 512 512 ];
+    virtualisation.memorySize = 1024;
+
+    environment.systemPackages = [ pkgs.cryptsetup ];
 
     fileSystems = lib.mkVMOverride {
       "/test-x-initrd-mount" = {
@@ -50,6 +53,13 @@ import ./make-test-python.nix ({ pkgs, ... }: {
         fi
       '';
     };
+
+    systemd.watchdog = {
+      device = "/dev/watchdog";
+      runtimeTime = "30s";
+      rebootTime = "10min";
+      kexecTime = "5min";
+    };
   };
 
   testScript = ''
@@ -97,6 +107,11 @@ import ./make-test-python.nix ({ pkgs, ... }: {
             re.search(r"^Filesystem state: *clean$", extinfo, re.MULTILINE) is not None
         ), ("File system was not cleanly unmounted: " + extinfo)
 
+    # Regression test for https://github.com/NixOS/nixpkgs/pull/91232
+    with subtest("setting transient hostnames works"):
+        machine.succeed("hostnamectl set-hostname --transient machine-transient")
+        machine.fail("hostnamectl set-hostname machine-all")
+
     with subtest("systemd-shutdown works"):
         machine.shutdown()
         machine.wait_for_unit("multi-user.target")
@@ -117,5 +132,41 @@ import ./make-test-python.nix ({ pkgs, ... }: {
         retcode, output = machine.execute("systemctl status testservice1.service")
         assert retcode in [0, 3]  # https://bugs.freedesktop.org/show_bug.cgi?id=77507
         assert "CPU:" in output
+
+    # Test systemd is configured to manage a watchdog
+    with subtest("systemd manages hardware watchdog"):
+        machine.wait_for_unit("multi-user.target")
+
+        # It seems that the device's path doesn't appear in 'systemctl show' so
+        # check it separately.
+        assert "WatchdogDevice=/dev/watchdog" in machine.succeed(
+            "cat /etc/systemd/system.conf"
+        )
+
+        output = machine.succeed("systemctl show | grep Watchdog")
+        # assert "RuntimeWatchdogUSec=30s" in output
+        # for some reason RuntimeWatchdogUSec, doesn't seem to be updated in here.
+        assert "RebootWatchdogUSec=10min" in output
+        assert "KExecWatchdogUSec=5min" in output
+
+    # Test systemd cryptsetup support
+    with subtest("systemd successfully reads /etc/crypttab and unlocks volumes"):
+        # create a luks volume and put a filesystem on it
+        machine.succeed(
+            "echo -n supersecret | cryptsetup luksFormat -q /dev/vdc -",
+            "echo -n supersecret | cryptsetup luksOpen --key-file - /dev/vdc foo",
+            "mkfs.ext3 /dev/mapper/foo",
+        )
+
+        # create a keyfile and /etc/crypttab
+        machine.succeed("echo -n supersecret > /var/lib/luks-keyfile")
+        machine.succeed("chmod 600 /var/lib/luks-keyfile")
+        machine.succeed("echo 'luks1 /dev/vdc /var/lib/luks-keyfile luks' > /etc/crypttab")
+
+        # after a reboot, systemd should unlock the volume and we should be able to mount it
+        machine.shutdown()
+        machine.succeed("systemctl status systemd-cryptsetup@luks1.service")
+        machine.succeed("mkdir -p /tmp/luks1")
+        machine.succeed("mount /dev/mapper/luks1 /tmp/luks1")
   '';
 })
diff --git a/nixos/tests/taskserver.nix b/nixos/tests/taskserver.nix
index ab9b589f85930..f34782c7059a9 100644
--- a/nixos/tests/taskserver.nix
+++ b/nixos/tests/taskserver.nix
@@ -1,4 +1,4 @@
-import ./make-test.nix ({ pkgs, ... }: let
+import ./make-test-python.nix ({ pkgs, ... }: let
   snakeOil = pkgs.runCommand "snakeoil-certs" {
     outputs = [ "out" "cacert" "cert" "key" "crl" ];
     buildInputs = [ pkgs.gnutls.bin ];
@@ -105,186 +105,178 @@ in {
     newServerSystem = nodes.newServer.config.system.build.toplevel;
     switchToNewServer = "${newServerSystem}/bin/switch-to-configuration test";
   in ''
-    sub su ($$) {
-      my ($user, $cmd) = @_;
-      my $esc = $cmd =~ s/'/'\\${"'"}'/gr;
-      return "su - $user -c '$esc'";
-    }
-
-    sub setupClientsFor ($$;$) {
-      my ($org, $user, $extraInit) = @_;
-
-      for my $client ($client1, $client2) {
-        $client->nest("initialize client for user $user", sub {
-          $client->succeed(
-            (su $user, "rm -rf /home/$user/.task"),
-            (su $user, "task rc.confirmation=no config confirmation no")
-          );
-
-          my $exportinfo = $server->succeed(
-            "nixos-taskserver user export $org $user"
-          );
-
-          $exportinfo =~ s/'/'\\'''/g;
-
-          $client->nest("importing taskwarrior configuration", sub {
-            my $cmd = su $user, "eval '$exportinfo' >&2";
-            my ($status, $out) = $client->execute_($cmd);
-            if ($status != 0) {
-              $client->log("output: $out");
-              die "command `$cmd' did not succeed (exit code $status)\n";
-            }
-          });
-
-          eval { &$extraInit($client, $org, $user) };
-
-          $client->succeed(su $user,
-            "task config taskd.server server:${portStr} >&2"
-          );
-
-          $client->succeed(su $user, "task sync init >&2");
-        });
-      }
-    }
-
-    sub restartServer {
-      $server->succeed("systemctl restart taskserver.service");
-      $server->waitForOpenPort(${portStr});
-    }
-
-    sub readdImperativeUser {
-      $server->nest("(re-)add imperative user bar", sub {
-        $server->execute("nixos-taskserver org remove imperativeOrg");
-        $server->succeed(
-          "nixos-taskserver org add imperativeOrg",
-          "nixos-taskserver user add imperativeOrg bar"
-        );
-        setupClientsFor "imperativeOrg", "bar";
-      });
-    }
-
-    sub testSync ($) {
-      my $user = $_[0];
-      subtest "sync for user $user", sub {
-        $client1->succeed(su $user, "task add foo >&2");
-        $client1->succeed(su $user, "task sync >&2");
-        $client2->fail(su $user, "task list >&2");
-        $client2->succeed(su $user, "task sync >&2");
-        $client2->succeed(su $user, "task list >&2");
-      };
-    }
-
-    sub checkClientCert ($) {
-      my $user = $_[0];
-      my $cmd = "gnutls-cli".
-        " --x509cafile=/home/$user/.task/keys/ca.cert".
-        " --x509keyfile=/home/$user/.task/keys/private.key".
-        " --x509certfile=/home/$user/.task/keys/public.cert".
-        " --port=${portStr} server < /dev/null";
-      return su $user, $cmd;
-    }
+    from shlex import quote
+
+
+    def su(user, cmd):
+        return f"su - {user} -c {quote(cmd)}"
+
+
+    def no_extra_init(client, org, user):
+        pass
+
+
+    def setup_clients_for(org, user, extra_init=no_extra_init):
+        for client in [client1, client2]:
+            with client.nested(f"initialize client for user {user}"):
+                client.succeed(
+                    su(user, f"rm -rf /home/{user}/.task"),
+                    su(user, "task rc.confirmation=no config confirmation no"),
+                )
+
+                exportinfo = server.succeed(f"nixos-taskserver user export {org} {user}")
+
+                with client.nested("importing taskwarrior configuration"):
+                    client.succeed(su(user, f"eval {quote(exportinfo)} >&2"))
+
+                extra_init(client, org, user)
+
+                client.succeed(su(user, "task config taskd.server server:${portStr} >&2"))
+
+                client.succeed(su(user, "task sync init >&2"))
+
+
+    def restart_server():
+        server.systemctl("restart taskserver.service")
+        server.wait_for_open_port(${portStr})
+
+
+    def re_add_imperative_user():
+        with server.nested("(re-)add imperative user bar"):
+            server.execute("nixos-taskserver org remove imperativeOrg")
+            server.succeed(
+                "nixos-taskserver org add imperativeOrg",
+                "nixos-taskserver user add imperativeOrg bar",
+            )
+            setup_clients_for("imperativeOrg", "bar")
+
+
+    def test_sync(user):
+        with subtest(f"sync for user {user}"):
+            client1.succeed(su(user, "task add foo >&2"))
+            client1.succeed(su(user, "task sync >&2"))
+            client2.fail(su(user, "task list >&2"))
+            client2.succeed(su(user, "task sync >&2"))
+            client2.succeed(su(user, "task list >&2"))
+
+
+    def check_client_cert(user):
+        # debug level 3 is a workaround for gnutls issue https://gitlab.com/gnutls/gnutls/-/issues/1040
+        cmd = (
+            f"gnutls-cli -d 3"
+            f" --x509cafile=/home/{user}/.task/keys/ca.cert"
+            f" --x509keyfile=/home/{user}/.task/keys/private.key"
+            f" --x509certfile=/home/{user}/.task/keys/public.cert"
+            f" --port=${portStr} server < /dev/null"
+        )
+        return su(user, cmd)
+
 
     # Explicitly start the VMs so that we don't accidentally start newServer
-    $server->start;
-    $client1->start;
-    $client2->start;
+    server.start()
+    client1.start()
+    client2.start()
 
-    $server->waitForUnit("taskserver.service");
+    server.wait_for_unit("taskserver.service")
 
-    $server->succeed(
-      "nixos-taskserver user list testOrganisation | grep -qxF alice",
-      "nixos-taskserver user list testOrganisation | grep -qxF foo",
-      "nixos-taskserver user list anotherOrganisation | grep -qxF bob"
-    );
+    server.succeed(
+        "nixos-taskserver user list testOrganisation | grep -qxF alice",
+        "nixos-taskserver user list testOrganisation | grep -qxF foo",
+        "nixos-taskserver user list anotherOrganisation | grep -qxF bob",
+    )
 
-    $server->waitForOpenPort(${portStr});
+    server.wait_for_open_port(${portStr})
 
-    $client1->waitForUnit("multi-user.target");
-    $client2->waitForUnit("multi-user.target");
+    client1.wait_for_unit("multi-user.target")
+    client2.wait_for_unit("multi-user.target")
 
-    setupClientsFor "testOrganisation", "alice";
-    setupClientsFor "testOrganisation", "foo";
-    setupClientsFor "anotherOrganisation", "bob";
+    setup_clients_for("testOrganisation", "alice")
+    setup_clients_for("testOrganisation", "foo")
+    setup_clients_for("anotherOrganisation", "bob")
 
-    testSync $_ for ("alice", "bob", "foo");
+    for user in ["alice", "bob", "foo"]:
+        test_sync(user)
 
-    $server->fail("nixos-taskserver user add imperativeOrg bar");
-    readdImperativeUser;
+    server.fail("nixos-taskserver user add imperativeOrg bar")
+    re_add_imperative_user()
 
-    testSync "bar";
+    test_sync("bar")
 
-    subtest "checking certificate revocation of user bar", sub {
-      $client1->succeed(checkClientCert "bar");
+    with subtest("checking certificate revocation of user bar"):
+        client1.succeed(check_client_cert("bar"))
 
-      $server->succeed("nixos-taskserver user remove imperativeOrg bar");
-      restartServer;
+        server.succeed("nixos-taskserver user remove imperativeOrg bar")
+        restart_server()
 
-      $client1->fail(checkClientCert "bar");
+        client1.fail(check_client_cert("bar"))
 
-      $client1->succeed(su "bar", "task add destroy everything >&2");
-      $client1->fail(su "bar", "task sync >&2");
-    };
+        client1.succeed(su("bar", "task add destroy everything >&2"))
+        client1.fail(su("bar", "task sync >&2"))
 
-    readdImperativeUser;
+    re_add_imperative_user()
 
-    subtest "checking certificate revocation of org imperativeOrg", sub {
-      $client1->succeed(checkClientCert "bar");
+    with subtest("checking certificate revocation of org imperativeOrg"):
+        client1.succeed(check_client_cert("bar"))
 
-      $server->succeed("nixos-taskserver org remove imperativeOrg");
-      restartServer;
+        server.succeed("nixos-taskserver org remove imperativeOrg")
+        restart_server()
 
-      $client1->fail(checkClientCert "bar");
+        client1.fail(check_client_cert("bar"))
 
-      $client1->succeed(su "bar", "task add destroy even more >&2");
-      $client1->fail(su "bar", "task sync >&2");
-    };
+        client1.succeed(su("bar", "task add destroy even more >&2"))
+        client1.fail(su("bar", "task sync >&2"))
 
-    readdImperativeUser;
+    re_add_imperative_user()
 
-    subtest "check whether declarative config overrides user bar", sub {
-      restartServer;
-      testSync "bar";
-    };
+    with subtest("check whether declarative config overrides user bar"):
+        restart_server()
+        test_sync("bar")
 
-    subtest "check manual configuration", sub {
-      # Remove the keys from automatic CA creation, to make sure the new
-      # generation doesn't use keys from before.
-      $server->succeed('rm -rf ${cfg.dataDir}/keys/* >&2');
-
-      $server->succeed('${switchToNewServer} >&2');
-      $server->waitForUnit("taskserver.service");
-      $server->waitForOpenPort(${portStr});
-
-      $server->succeed(
-        "nixos-taskserver org add manualOrg",
-        "nixos-taskserver user add manualOrg alice"
-      );
-
-      setupClientsFor "manualOrg", "alice", sub {
-        my ($client, $org, $user) = @_;
-        my $cfgpath = "/home/$user/.task";
-
-        $client->copyFileFromHost("${snakeOil.cacert}", "$cfgpath/ca.cert");
-        for my $file ('alice.key', 'alice.cert') {
-          $client->copyFileFromHost("${snakeOil}/$file", "$cfgpath/$file");
-        }
-
-        for my $file ("$user.key", "$user.cert") {
-          $client->copyFileFromHost(
-            "${snakeOil}/$file", "$cfgpath/$file"
-          );
-        }
-        $client->copyFileFromHost(
-          "${snakeOil.cacert}", "$cfgpath/ca.cert"
-        );
-        $client->succeed(
-          (su "alice", "task config taskd.ca $cfgpath/ca.cert"),
-          (su "alice", "task config taskd.key $cfgpath/$user.key"),
-          (su $user, "task config taskd.certificate $cfgpath/$user.cert")
-        );
-      };
 
-      testSync "alice";
-    };
+    def init_manual_config(client, org, user):
+        cfgpath = f"/home/{user}/.task"
+
+        client.copy_from_host(
+            "${snakeOil.cacert}",
+            f"{cfgpath}/ca.cert",
+        )
+        for file in ["alice.key", "alice.cert"]:
+            client.copy_from_host(
+                f"${snakeOil}/{file}",
+                f"{cfgpath}/{file}",
+            )
+
+        for file in [f"{user}.key", f"{user}.cert"]:
+            client.copy_from_host(
+                f"${snakeOil}/{file}",
+                f"{cfgpath}/{file}",
+            )
+
+        client.succeed(
+            su("alice", f"task config taskd.ca {cfgpath}/ca.cert"),
+            su("alice", f"task config taskd.key {cfgpath}/{user}.key"),
+            su(user, f"task config taskd.certificate {cfgpath}/{user}.cert"),
+        )
+
+
+    with subtest("check manual configuration"):
+        # Remove the keys from automatic CA creation, to make sure the new
+        # generation doesn't use keys from before.
+        server.succeed("rm -rf ${cfg.dataDir}/keys/* >&2")
+
+        server.succeed(
+            "${switchToNewServer} >&2"
+        )
+        server.wait_for_unit("taskserver.service")
+        server.wait_for_open_port(${portStr})
+
+        server.succeed(
+            "nixos-taskserver org add manualOrg",
+            "nixos-taskserver user add manualOrg alice",
+        )
+
+        setup_clients_for("manualOrg", "alice", init_manual_config)
+
+        test_sync("alice")
   '';
 })
diff --git a/nixos/tests/tiddlywiki.nix b/nixos/tests/tiddlywiki.nix
index cf45578b0f989..822711b8939c5 100644
--- a/nixos/tests/tiddlywiki.nix
+++ b/nixos/tests/tiddlywiki.nix
@@ -44,7 +44,7 @@ import ./make-test-python.nix ({ ... }: {
           configured.succeed(
               "curl --fail -o /dev/null 127.0.0.1:3000 --user somelogin:somesecret"
           )
-      
+
       with subtest("restart preserves changes"):
           # given running wiki
           default.wait_for_unit("tiddlywiki.service")
diff --git a/nixos/tests/transmission.nix b/nixos/tests/transmission.nix
index f4f2186be1fff..37c0352dcfb8f 100644
--- a/nixos/tests/transmission.nix
+++ b/nixos/tests/transmission.nix
@@ -9,6 +9,8 @@ import ./make-test-python.nix ({ pkgs, ...} : {
 
     networking.firewall.allowedTCPPorts = [ 9091 ];
 
+    security.apparmor.enable = true;
+
     services.transmission.enable = true;
   };
 
diff --git a/nixos/tests/trezord.nix b/nixos/tests/trezord.nix
index 8d908a5224923..b7b3dd31942bb 100644
--- a/nixos/tests/trezord.nix
+++ b/nixos/tests/trezord.nix
@@ -1,9 +1,8 @@
 import ./make-test-python.nix ({ pkgs, ... }: {
   name = "trezord";
-  meta = with pkgs.stdenv.lib.maintainers; {
-    maintainers = [ mmahut "1000101" ];
+  meta = with pkgs.stdenv.lib; {
+    maintainers = with maintainers; [ mmahut _1000101 ];
   };
-
   nodes = {
     machine = { ... }: {
       services.trezord.enable = true;
diff --git a/nixos/tests/trickster.nix b/nixos/tests/trickster.nix
index e2ca00980d539..713ac8f0b2fae 100644
--- a/nixos/tests/trickster.nix
+++ b/nixos/tests/trickster.nix
@@ -1,7 +1,7 @@
 import ./make-test-python.nix ({ pkgs, ... }: {
   name = "trickster";
-  meta = with pkgs.stdenv.lib.maintainers; {
-    maintainers = [ "1000101" ];
+  meta = with pkgs.stdenv.lib; {
+    maintainers = with maintainers; [ _1000101 ];
   };
 
   nodes = {
@@ -34,4 +34,4 @@ import ./make-test-python.nix ({ pkgs, ... }: {
         "curl -L http://localhost:9090/metrics | grep 'promhttp_metric_handler_requests_total{code=\"500\"} 0'"
     )
   '';
-})
\ No newline at end of file
+})
diff --git a/nixos/tests/v2ray.nix b/nixos/tests/v2ray.nix
new file mode 100644
index 0000000000000..f1b2570cc8604
--- /dev/null
+++ b/nixos/tests/v2ray.nix
@@ -0,0 +1,83 @@
+import ./make-test-python.nix ({ lib, pkgs, ... }: let
+
+  v2rayUser = {
+    # A random UUID.
+    id = "a6a46834-2150-45f8-8364-0f6f6ab32384";
+    alterId = 4;
+  };
+
+  # 1080 [http proxy] -> 1081 [vmess] -> direct
+  v2rayConfig = {
+    inbounds = [
+      {
+        tag = "http_in";
+        port = 1080;
+        listen = "127.0.0.1";
+        protocol = "http";
+      }
+      {
+        tag = "vmess_in";
+        port = 1081;
+        listen = "127.0.0.1";
+        protocol = "vmess";
+        settings.clients = [v2rayUser];
+      }
+    ];
+    outbounds = [
+      {
+        tag = "vmess_out";
+        protocol = "vmess";
+        settings.vnext = [{
+          address = "127.0.0.1";
+          port = 1081;
+          users = [v2rayUser];
+        }];
+      }
+      {
+        tag = "direct";
+        protocol = "freedom";
+      }
+    ];
+    routing.rules = [
+      {
+        type = "field";
+        inboundTag = "http_in";
+        outboundTag = "vmess_out";
+      }
+      {
+        type = "field";
+        inboundTag = "vmess_in";
+        outboundTag = "direct";
+      }
+    ];
+  };
+
+in {
+  name = "v2ray";
+  meta = with lib.maintainers; {
+    maintainers = [ servalcatty ];
+  };
+  machine = { pkgs, ... }: {
+    environment.systemPackages = [ pkgs.curl ];
+    services.v2ray = {
+      enable = true;
+      config = v2rayConfig;
+    };
+    services.httpd = {
+      enable = true;
+      adminAddr = "foo@example.org";
+    };
+  };
+
+  testScript = ''
+    start_all()
+
+    machine.wait_for_unit("httpd.service")
+    machine.wait_for_unit("v2ray.service")
+    machine.wait_for_open_port(80)
+    machine.wait_for_open_port(1080)
+    machine.succeed(
+        "curl --fail --max-time 10 --proxy http://localhost:1080 http://localhost"
+    )
+  '';
+})
diff --git a/nixos/tests/virtualbox.nix b/nixos/tests/virtualbox.nix
index aec8da6a2af3c..0d9eafa4a20f3 100644
--- a/nixos/tests/virtualbox.nix
+++ b/nixos/tests/virtualbox.nix
@@ -15,7 +15,7 @@
 
 assert use64bitGuest -> useKvmNestedVirt;
 
-with import ../lib/testing.nix { inherit system pkgs; };
+with import ../lib/testing-python.nix { inherit system pkgs; };
 with pkgs.lib;
 
 let
@@ -91,13 +91,15 @@ let
       (isYes "SERIAL_8250_CONSOLE")
       (isYes "SERIAL_8250")
     ];
+
+    networking.usePredictableInterfaceNames = false;
   };
 
   mkLog = logfile: tag: let
     rotated = map (i: "${logfile}.${toString i}") (range 1 9);
     all = concatMapStringsSep " " (f: "\"${f}\"") ([logfile] ++ rotated);
     logcmd = "tail -F ${all} 2> /dev/null | logger -t \"${tag}\"";
-  in optionalString debug "$machine->execute(ru '${logcmd} & disown');";
+  in if debug then "machine.execute(ru('${logcmd} & disown'))" else "pass";
 
   testVM = vmName: vmScript: let
     cfg = (import ../lib/eval-config.nix {
@@ -198,103 +200,111 @@ let
       systemd.services."vboxtestlog-${name}@" = {
         description = "VirtualBox Test Machine Log For ${name}";
         serviceConfig.StandardInput = "socket";
-        serviceConfig.StandardOutput = "syslog";
         serviceConfig.SyslogIdentifier = "GUEST-${name}";
         serviceConfig.ExecStart = "${pkgs.coreutils}/bin/cat";
       };
     };
 
     testSubs = ''
-      my ${"$" + name}_sharepath = '${sharePath}';
-
-      sub checkRunning_${name} {
-        my $cmd = 'VBoxManage list runningvms | grep -q "^\"${name}\""';
-        my ($status, $out) = $machine->execute(ru $cmd);
-        return $status == 0;
-      }
-
-      sub cleanup_${name} {
-        $machine->execute(ru "VBoxManage controlvm ${name} poweroff")
-          if checkRunning_${name};
-        $machine->succeed("rm -rf ${sharePath}");
-        $machine->succeed("mkdir -p ${sharePath}");
-        $machine->succeed("chown alice.users ${sharePath}");
-      }
-
-      sub createVM_${name} {
-        vbm("createvm --name ${name} ${createFlags}");
-        vbm("modifyvm ${name} ${vmFlags}");
-        vbm("setextradata ${name} VBoxInternal/PDM/HaltOnReset 1");
-        vbm("storagectl ${name} ${controllerFlags}");
-        vbm("storageattach ${name} ${diskFlags}");
-        vbm("sharedfolder add ${name} ${sharedFlags}");
-        vbm("sharedfolder add ${name} ${nixstoreFlags}");
-        cleanup_${name};
-
-        ${mkLog "$HOME/VirtualBox VMs/${name}/Logs/VBox.log" "HOST-${name}"}
-      }
-
-      sub destroyVM_${name} {
-        cleanup_${name};
-        vbm("unregistervm ${name} --delete");
-      }
-
-      sub waitForVMBoot_${name} {
-        $machine->execute(ru(
-          'set -e; i=0; '.
-          'while ! test -e ${sharePath}/boot-done; do '.
-          'sleep 10; i=$(($i + 10)); [ $i -le 3600 ]; '.
-          'VBoxManage list runningvms | grep -q "^\"${name}\""; '.
-          'done'
-        ));
-      }
-
-      sub waitForIP_${name} ($) {
-        my $property = "/VirtualBox/GuestInfo/Net/$_[0]/V4/IP";
-        my $getip = "VBoxManage guestproperty get ${name} $property | ".
-                    "sed -n -e 's/^Value: //p'";
-        my $ip = $machine->succeed(ru(
-          'for i in $(seq 1000); do '.
-          'if ipaddr="$('.$getip.')" && [ -n "$ipaddr" ]; then '.
-          'echo "$ipaddr"; exit 0; '.
-          'fi; '.
-          'sleep 1; '.
-          'done; '.
-          'echo "Could not get IPv4 address for ${name}!" >&2; '.
-          'exit 1'
-        ));
-        chomp $ip;
-        return $ip;
-      }
-
-      sub waitForStartup_${name} {
-        for (my $i = 0; $i <= 120; $i += 10) {
-          $machine->sleep(10);
-          return if checkRunning_${name};
-          eval { $_[0]->() } if defined $_[0];
-        }
-        die "VirtualBox VM didn't start up within 2 minutes";
-      }
-
-      sub waitForShutdown_${name} {
-        for (my $i = 0; $i <= 120; $i += 10) {
-          $machine->sleep(10);
-          return unless checkRunning_${name};
-        }
-        die "VirtualBox VM didn't shut down within 2 minutes";
-      }
-
-      sub shutdownVM_${name} {
-        $machine->succeed(ru "touch ${sharePath}/shutdown");
-        $machine->execute(
-          'set -e; i=0; '.
-          'while test -e ${sharePath}/shutdown '.
-          '        -o -e ${sharePath}/boot-done; do '.
-          'sleep 1; i=$(($i + 1)); [ $i -le 3600 ]; '.
-          'done'
-        );
-        waitForShutdown_${name};
-      }
+
+
+      ${name}_sharepath = "${sharePath}"
+
+
+      def check_running_${name}():
+          cmd = "VBoxManage list runningvms | grep -q '^\"${name}\"'"
+          (status, _) = machine.execute(ru(cmd))
+          return status == 0
+
+
+      def cleanup_${name}():
+          if check_running_${name}():
+              machine.execute(ru("VBoxManage controlvm ${name} poweroff"))
+          machine.succeed("rm -rf ${sharePath}")
+          machine.succeed("mkdir -p ${sharePath}")
+          machine.succeed("chown alice.users ${sharePath}")
+
+
+      def create_vm_${name}():
+          # fmt: off
+          vbm(f"createvm --name ${name} ${createFlags}")
+          vbm(f"modifyvm ${name} ${vmFlags}")
+          vbm(f"setextradata ${name} VBoxInternal/PDM/HaltOnReset 1")
+          vbm(f"storagectl ${name} ${controllerFlags}")
+          vbm(f"storageattach ${name} ${diskFlags}")
+          vbm(f"sharedfolder add ${name} ${sharedFlags}")
+          vbm(f"sharedfolder add ${name} ${nixstoreFlags}")
+          cleanup_${name}()
+
+          ${mkLog "$HOME/VirtualBox VMs/${name}/Logs/VBox.log" "HOST-${name}"}
+          # fmt: on
+
+
+      def destroy_vm_${name}():
+          cleanup_${name}()
+          vbm("unregistervm ${name} --delete")
+
+
+      def wait_for_vm_boot_${name}():
+          machine.execute(
+              ru(
+                  "set -e; i=0; "
+                  "while ! test -e ${sharePath}/boot-done; do "
+                  "sleep 10; i=$(($i + 10)); [ $i -le 3600 ]; "
+                  "VBoxManage list runningvms | grep -q '^\"${name}\"'; "
+                  "done"
+              )
+          )
+
+
+      def wait_for_ip_${name}(interface):
+          property = f"/VirtualBox/GuestInfo/Net/{interface}/V4/IP"
+          # fmt: off
+          getip = f"VBoxManage guestproperty get ${name} {property} | sed -n -e 's/^Value: //p'"
+          # fmt: on
+
+          ip = machine.succeed(
+              ru(
+                  "for i in $(seq 1000); do "
+                  f'if ipaddr="$({getip})" && [ -n "$ipaddr" ]; then '
+                  'echo "$ipaddr"; exit 0; '
+                  "fi; "
+                  "sleep 1; "
+                  "done; "
+                  "echo 'Could not get IPv4 address for ${name}!' >&2; "
+                  "exit 1"
+              )
+          ).strip()
+          return ip
+
+
+      def wait_for_startup_${name}(nudge=lambda: None):
+          for _ in range(0, 130, 10):
+              machine.sleep(10)
+              if check_running_${name}():
+                  return
+              nudge()
+          raise Exception("VirtualBox VM didn't start up within 2 minutes")
+
+
+      def wait_for_shutdown_${name}():
+          for _ in range(0, 130, 10):
+              machine.sleep(10)
+              if not check_running_${name}():
+                  return
+          raise Exception("VirtualBox VM didn't shut down within 2 minutes")
+
+
+      def shutdown_vm_${name}():
+          machine.succeed(ru("touch ${sharePath}/shutdown"))
+          machine.execute(
+              "set -e; i=0; "
+              "while test -e ${sharePath}/shutdown "
+              "        -o -e ${sharePath}/boot-done; do "
+              "sleep 1; i=$(($i + 1)); [ $i -le 3600 ]; "
+              "done"
+          )
+          wait_for_shutdown_${name}()
     '';
   };
 
@@ -365,26 +375,31 @@ let
     };
 
     testScript = ''
-      sub ru ($) {
-        my $esc = $_[0] =~ s/'/'\\${"'"}'/gr;
-        return "su - alice -c '$esc'";
-      }
+      from shlex import quote
+      ${concatStrings (mapAttrsToList (_: getAttr "testSubs") vms)}
 
-      sub vbm {
-        $machine->succeed(ru("VBoxManage ".$_[0]));
-      };
+      def ru(cmd: str) -> str:
+          return f"su - alice -c {quote(cmd)}"
 
-      sub removeUUIDs {
-        return join("\n", grep { $_ !~ /^UUID:/ } split(/\n/, $_[0]))."\n";
-      }
 
-      ${concatStrings (mapAttrsToList (_: getAttr "testSubs") vms)}
+      def vbm(cmd: str) -> str:
+          return machine.succeed(ru(f"VBoxManage {cmd}"))
+
+
+      def remove_uuids(output: str) -> str:
+          return "\n".join(
+              [line for line in (output or "").splitlines() if not line.startswith("UUID:")]
+          )
+
 
-      $machine->waitForX;
+      machine.wait_for_x()
 
+      # fmt: off
       ${mkLog "$HOME/.config/VirtualBox/VBoxSVC.log" "HOST-SVC"}
+      # fmt: on
 
       ${testScript}
+      # (keep black happy)
     '';
 
     meta = with pkgs.stdenv.lib.maintainers; {
@@ -394,133 +409,129 @@ let
 
   unfreeTests = mapAttrs (mkVBoxTest true vboxVMsWithExtpack) {
     enable-extension-pack = ''
-      createVM_testExtensionPack;
-      vbm("startvm testExtensionPack");
-      waitForStartup_testExtensionPack;
-      $machine->screenshot("cli_started");
-      waitForVMBoot_testExtensionPack;
-      $machine->screenshot("cli_booted");
-
-      $machine->nest("Checking for privilege escalation", sub {
-        $machine->fail("test -e '/root/VirtualBox VMs'");
-        $machine->fail("test -e '/root/.config/VirtualBox'");
-        $machine->succeed("test -e '/home/alice/VirtualBox VMs'");
-      });
-
-      shutdownVM_testExtensionPack;
-      destroyVM_testExtensionPack;
+      create_vm_testExtensionPack()
+      vbm("startvm testExtensionPack")
+      wait_for_startup_testExtensionPack()
+      machine.screenshot("cli_started")
+      wait_for_vm_boot_testExtensionPack()
+      machine.screenshot("cli_booted")
+
+      with machine.nested("Checking for privilege escalation"):
+          machine.fail("test -e '/root/VirtualBox VMs'")
+          machine.fail("test -e '/root/.config/VirtualBox'")
+          machine.succeed("test -e '/home/alice/VirtualBox VMs'")
+
+      shutdown_vm_testExtensionPack()
+      destroy_vm_testExtensionPack()
     '';
   };
 
 in mapAttrs (mkVBoxTest false vboxVMs) {
   simple-gui = ''
-    createVM_simple;
-    $machine->succeed(ru "VirtualBox &");
-    $machine->waitUntilSucceeds(
-      ru "xprop -name 'Oracle VM VirtualBox Manager'"
-    );
-    $machine->sleep(5);
-    $machine->screenshot("gui_manager_started");
     # Home to select Tools, down to move to the VM, enter to start it.
-    $machine->sendKeys("home");
-    $machine->sendKeys("down");
-    $machine->sendKeys("ret");
-    $machine->screenshot("gui_manager_sent_startup");
-    waitForStartup_simple (sub {
-      $machine->sendKeys("home");
-      $machine->sendKeys("down");
-      $machine->sendKeys("ret");
-    });
-    $machine->screenshot("gui_started");
-    waitForVMBoot_simple;
-    $machine->screenshot("gui_booted");
-    shutdownVM_simple;
-    $machine->sleep(5);
-    $machine->screenshot("gui_stopped");
-    $machine->sendKeys("ctrl-q");
-    $machine->sleep(5);
-    $machine->screenshot("gui_manager_stopped");
-    destroyVM_simple;
+    def send_vm_startup():
+        machine.send_key("home")
+        machine.send_key("down")
+        machine.send_key("ret")
+
+
+    create_vm_simple()
+    machine.succeed(ru("VirtualBox &"))
+    machine.wait_until_succeeds(ru("xprop -name 'Oracle VM VirtualBox Manager'"))
+    machine.sleep(5)
+    machine.screenshot("gui_manager_started")
+    send_vm_startup()
+    machine.screenshot("gui_manager_sent_startup")
+    wait_for_startup_simple(send_vm_startup)
+    machine.screenshot("gui_started")
+    wait_for_vm_boot_simple()
+    machine.screenshot("gui_booted")
+    shutdown_vm_simple()
+    machine.sleep(5)
+    machine.screenshot("gui_stopped")
+    machine.send_key("ctrl-q")
+    machine.sleep(5)
+    machine.screenshot("gui_manager_stopped")
+    destroy_vm_simple()
   '';
 
   simple-cli = ''
-    createVM_simple;
-    vbm("startvm simple");
-    waitForStartup_simple;
-    $machine->screenshot("cli_started");
-    waitForVMBoot_simple;
-    $machine->screenshot("cli_booted");
-
-    $machine->nest("Checking for privilege escalation", sub {
-      $machine->fail("test -e '/root/VirtualBox VMs'");
-      $machine->fail("test -e '/root/.config/VirtualBox'");
-      $machine->succeed("test -e '/home/alice/VirtualBox VMs'");
-    });
-
-    shutdownVM_simple;
-    destroyVM_simple;
+    create_vm_simple()
+    vbm("startvm simple")
+    wait_for_startup_simple()
+    machine.screenshot("cli_started")
+    wait_for_vm_boot_simple()
+    machine.screenshot("cli_booted")
+
+    with machine.nested("Checking for privilege escalation"):
+        machine.fail("test -e '/root/VirtualBox VMs'")
+        machine.fail("test -e '/root/.config/VirtualBox'")
+        machine.succeed("test -e '/home/alice/VirtualBox VMs'")
+
+    shutdown_vm_simple()
+    destroy_vm_simple()
   '';
 
   headless = ''
-    createVM_headless;
-    $machine->succeed(ru("VBoxHeadless --startvm headless & disown %1"));
-    waitForStartup_headless;
-    waitForVMBoot_headless;
-    shutdownVM_headless;
-    destroyVM_headless;
+    create_vm_headless()
+    machine.succeed(ru("VBoxHeadless --startvm headless & disown %1"))
+    wait_for_startup_headless()
+    wait_for_vm_boot_headless()
+    shutdown_vm_headless()
+    destroy_vm_headless()
   '';
 
   host-usb-permissions = ''
-    my $userUSB = removeUUIDs vbm("list usbhost");
-    print STDERR $userUSB;
-    my $rootUSB = removeUUIDs $machine->succeed("VBoxManage list usbhost");
-    print STDERR $rootUSB;
-
-    die "USB host devices differ for root and normal user"
-      if $userUSB ne $rootUSB;
-    die "No USB host devices found" if $userUSB =~ /<none>/;
+    user_usb = remove_uuids(vbm("list usbhost"))
+    print(user_usb, file=sys.stderr)
+    root_usb = remove_uuids(machine.succeed("VBoxManage list usbhost"))
+    print(root_usb, file=sys.stderr)
+
+    if user_usb != root_usb:
+        raise Exception("USB host devices differ for root and normal user")
+    if "<none>" in user_usb:
+        raise Exception("No USB host devices found")
   '';
 
   systemd-detect-virt = ''
-    createVM_detectvirt;
-    vbm("startvm detectvirt");
-    waitForStartup_detectvirt;
-    waitForVMBoot_detectvirt;
-    shutdownVM_detectvirt;
-    my $result = $machine->succeed("cat '$detectvirt_sharepath/result'");
-    chomp $result;
-    destroyVM_detectvirt;
-    die "systemd-detect-virt returned \"$result\" instead of \"oracle\""
-      if $result ne "oracle";
+    create_vm_detectvirt()
+    vbm("startvm detectvirt")
+    wait_for_startup_detectvirt()
+    wait_for_vm_boot_detectvirt()
+    shutdown_vm_detectvirt()
+    result = machine.succeed(f"cat '{detectvirt_sharepath}/result'").strip()
+    destroy_vm_detectvirt()
+    if result != "oracle":
+        raise Exception(f'systemd-detect-virt returned "{result}" instead of "oracle"')
   '';
 
   net-hostonlyif = ''
-    createVM_test1;
-    createVM_test2;
+    create_vm_test1()
+    create_vm_test2()
 
-    vbm("startvm test1");
-    waitForStartup_test1;
-    waitForVMBoot_test1;
+    vbm("startvm test1")
+    wait_for_startup_test1()
+    wait_for_vm_boot_test1()
 
-    vbm("startvm test2");
-    waitForStartup_test2;
-    waitForVMBoot_test2;
+    vbm("startvm test2")
+    wait_for_startup_test2()
+    wait_for_vm_boot_test2()
 
-    $machine->screenshot("net_booted");
+    machine.screenshot("net_booted")
 
-    my $test1IP = waitForIP_test1 1;
-    my $test2IP = waitForIP_test2 1;
+    test1_ip = wait_for_ip_test1(1)
+    test2_ip = wait_for_ip_test2(1)
 
-    $machine->succeed("echo '$test2IP' | nc -N '$test1IP' 1234");
-    $machine->succeed("echo '$test1IP' | nc -N '$test2IP' 1234");
+    machine.succeed(f"echo '{test2_ip}' | nc -N '{test1_ip}' 1234")
+    machine.succeed(f"echo '{test1_ip}' | nc -N '{test2_ip}' 1234")
 
-    $machine->waitUntilSucceeds("nc -N '$test1IP' 5678 < /dev/null >&2");
-    $machine->waitUntilSucceeds("nc -N '$test2IP' 5678 < /dev/null >&2");
+    machine.wait_until_succeeds(f"nc -N '{test1_ip}' 5678 < /dev/null >&2")
+    machine.wait_until_succeeds(f"nc -N '{test2_ip}' 5678 < /dev/null >&2")
 
-    shutdownVM_test1;
-    shutdownVM_test2;
+    shutdown_vm_test1()
+    shutdown_vm_test2()
 
-    destroyVM_test1;
-    destroyVM_test2;
+    destroy_vm_test1()
+    destroy_vm_test2()
   '';
 } // (if enableUnfree then unfreeTests else {})
diff --git a/nixos/tests/wasabibackend.nix b/nixos/tests/wasabibackend.nix
new file mode 100644
index 0000000000000..d169ad152722a
--- /dev/null
+++ b/nixos/tests/wasabibackend.nix
@@ -0,0 +1,38 @@
+import ./make-test-python.nix ({ pkgs, ... }: {
+  name = "wasabibackend";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ mmahut ];
+  };
+
+  nodes = {
+    machine = { ... }: {
+      services.wasabibackend = {
+        enable = true;
+        network = "testnet";
+        rpc = {
+          user = "alice";
+          port = 18332;
+        };
+      };
+      services.bitcoind = {
+        enable = true;
+        testnet = true;
+        rpc.users = {
+          alice.passwordHMAC = "e7096bc21da60b29ecdbfcdb2c3acc62$f948e61cb587c399358ed99c6ed245a41460b4bf75125d8330c9f6fcc13d7ae7";
+        };
+      };
+    };
+  };
+
+  testScript = ''
+    start_all()
+    machine.wait_for_unit("wasabibackend.service")
+    machine.wait_until_succeeds(
+        "grep 'Wasabi Backend started' /var/lib/wasabibackend/.walletwasabi/backend/Logs.txt"
+    )
+    machine.sleep(5)
+    machine.succeed(
+        "grep 'Config is successfully initialized' /var/lib/wasabibackend/.walletwasabi/backend/Logs.txt"
+    )
+  '';
+})
diff --git a/nixos/tests/xandikos.nix b/nixos/tests/xandikos.nix
index 0fded20ff1a9c..48c770a3d168d 100644
--- a/nixos/tests/xandikos.nix
+++ b/nixos/tests/xandikos.nix
@@ -4,7 +4,7 @@ import ./make-test-python.nix (
     {
       name = "xandikos";
 
-      meta.maintainers = [ lib.maintainers."0x4A6F" ];
+      meta.maintainers = with lib.maintainers; [ _0x4A6F ];
 
       nodes = {
         xandikos_client = {};
@@ -17,7 +17,7 @@ import ./make-test-python.nix (
           services.xandikos.enable = true;
           services.xandikos.address = "localhost";
           services.xandikos.port = 8080;
-          services.xandikos.routePrefix = "/xandikos/";
+          services.xandikos.routePrefix = "/xandikos-prefix/";
           services.xandikos.extraOptions = [
             "--defaults"
           ];
@@ -28,7 +28,7 @@ import ./make-test-python.nix (
               serverName = "xandikos.local";
               basicAuth.xandikos = "snakeOilPassword";
               locations."/xandikos/" = {
-                proxyPass = "http://localhost:8080/";
+                proxyPass = "http://localhost:8080/xandikos-prefix/";
               };
             };
           };
diff --git a/nixos/tests/xfce.nix b/nixos/tests/xfce.nix
index 99065669661a0..99e30342e5937 100644
--- a/nixos/tests/xfce.nix
+++ b/nixos/tests/xfce.nix
@@ -11,8 +11,8 @@ import ./make-test-python.nix ({ pkgs, ...} : {
 
       services.xserver.enable = true;
 
-      services.xserver.displayManager.lightdm = {
-        enable = true;
+      services.xserver.displayManager = {
+        lightdm.enable = true;
         autoLogin = {
           enable = true;
           user = "alice";
diff --git a/nixos/tests/xmpp/ejabberd.nix b/nixos/tests/xmpp/ejabberd.nix
index 1518aaacc8abb..2b09f99f5fd99 100644
--- a/nixos/tests/xmpp/ejabberd.nix
+++ b/nixos/tests/xmpp/ejabberd.nix
@@ -5,6 +5,10 @@ import ../make-test-python.nix ({ pkgs, ... }: {
   };
   nodes = {
     client = { nodes, pkgs, ... }: {
+      networking.extraHosts = ''
+        ${nodes.server.config.networking.primaryIPAddress} example.com
+      '';
+
       environment.systemPackages = [
         (pkgs.callPackage ./xmpp-sendmessage.nix { connectTo = nodes.server.config.networking.primaryIPAddress; })
       ];
@@ -46,6 +50,11 @@ import ../make-test-python.nix ({ pkgs, ... }: {
               module: ejabberd_service
               access: local
               shaper: fast
+            -
+              port: 5444
+              module: ejabberd_http
+              request_handlers:
+                "/upload": mod_http_upload
 
           ## Disabling digest-md5 SASL authentication. digest-md5 requires plain-text
           ## password storage (see auth_password_format option).
@@ -180,6 +189,7 @@ import ../make-test-python.nix ({ pkgs, ... }: {
             mod_client_state: {}
             mod_configure: {} # requires mod_adhoc
             ## mod_delegation: {} # for xep0356
+            mod_disco: {}
             #mod_irc:
             #  host: "irc.@HOST@"
             #  default_encoding: "utf-8"
@@ -187,9 +197,9 @@ import ../make-test-python.nix ({ pkgs, ... }: {
             ## mod_http_fileserver:
             ##   docroot: "/var/www"
             ##   accesslog: "/var/log/ejabberd/access.log"
-            #mod_http_upload:
-            #  thumbnail: false # otherwise needs the identify command from ImageMagick installed
-            #  put_url: "https://@HOST@:5444"
+            mod_http_upload:
+              thumbnail: false # otherwise needs the identify command from ImageMagick installed
+              put_url: "http://@HOST@:5444/upload"
             ##   # docroot: "@HOME@/upload"
             #mod_http_upload_quota:
             #  max_days: 14
diff --git a/nixos/tests/xmpp/xmpp-sendmessage.nix b/nixos/tests/xmpp/xmpp-sendmessage.nix
index 349b9c6f38e49..30945e68300a8 100644
--- a/nixos/tests/xmpp/xmpp-sendmessage.nix
+++ b/nixos/tests/xmpp/xmpp-sendmessage.nix
@@ -36,7 +36,11 @@ class CthonTest(ClientXMPP):
         def timeout_callback(arg):
             log.error("ERROR: Cannot upload file. XEP_0363 seems broken")
             sys.exit(1)
-        url = await self['xep_0363'].upload_file("${dummyFile}",timeout=10, timeout_callback=timeout_callback)
+        try:
+            url = await self['xep_0363'].upload_file("${dummyFile}",timeout=10, timeout_callback=timeout_callback)
+        except:
+            log.error("ERROR: Cannot run upload command. XEP_0363 seems broken")
+            sys.exit(1)
         log.info('Upload success!')
         # Test MUC
         self.plugin['xep_0045'].join_muc('testMucRoom', 'cthon98', wait=True)
diff --git a/nixos/tests/yggdrasil.nix b/nixos/tests/yggdrasil.nix
index 9ceb79747339e..1d7541308b481 100644
--- a/nixos/tests/yggdrasil.nix
+++ b/nixos/tests/yggdrasil.nix
@@ -7,6 +7,7 @@ let
     SigningPrivateKey = "fe3add8da35316c05f6d90d3ca79bd2801e6ccab6d37e5339fef4152589398abe2c43349083bc1e998e4ec4535b4c6a8f44ca9a5a8e07336561267253b2be5f4";
   };
   bobIp6 = "201:ebbd:bde9:f138:c302:4afa:1fb6:a19a";
+  bobPrefix = "301:ebbd:bde9:f138";
   bobConfig = {
     InterfacePeers = {
       eth1 = [ "tcp://192.168.1.200:12345" ];
@@ -18,6 +19,7 @@ let
     SigningPublicKey = "de111da0ec781e45bf6c63ecb45a78c24d7d4655abfaeea83b26c36eb5c0fd5b";
     SigningPrivateKey = "2a6c21550f3fca0331df50668ffab66b6dce8237bcd5728e571e8033b363e247de111da0ec781e45bf6c63ecb45a78c24d7d4655abfaeea83b26c36eb5c0fd5b";
   };
+  danIp6 = bobPrefix + "::2";
 
 in import ./make-test-python.nix ({ pkgs, ...} : {
   name = "yggdrasil";
@@ -69,6 +71,41 @@ in import ./make-test-python.nix ({ pkgs, ...} : {
                          text = builtins.toJSON bobConfig;
                        });
         };
+
+        boot.kernel.sysctl."net.ipv6.conf.all.forwarding" = 1;
+
+        networking = {
+          bridges.br0.interfaces = [ ];
+          interfaces.br0 = {
+            ipv6.addresses = [{
+              address = bobPrefix + "::1";
+              prefixLength = 64;
+            }];
+          };
+        };
+
+        # dan is a node inside a container running on bob's host.
+        containers.dan = {
+          autoStart = true;
+          privateNetwork = true;
+          hostBridge = "br0";
+          config = { config, pkgs, ... }: {
+            networking.interfaces.eth0.ipv6 = {
+              addresses = [{
+                address = bobPrefix + "::2";
+                prefixLength = 64;
+              }];
+              routes = [{
+                address = "200::";
+                prefixLength = 7;
+                via = bobPrefix + "::1";
+              }];
+            };
+            services.httpd.enable = true;
+            services.httpd.adminAddr = "foo@example.org";
+            networking.firewall.allowedTCPPorts = [ 80 ];
+          };
+        };
       };
 
     # Carol only does local peering.  Carol's yggdrasil config is all Nix.
@@ -100,7 +137,7 @@ in import ./make-test-python.nix ({ pkgs, ...} : {
 
       bob.start()
       carol.start()
-      bob.wait_for_unit("yggdrasil.service")
+      bob.wait_for_unit("default.target")
       carol.wait_for_unit("yggdrasil.service")
 
       ip_addr_show = "ip -o -6 addr show dev ygg0 scope global"
@@ -117,10 +154,13 @@ in import ./make-test-python.nix ({ pkgs, ...} : {
 
       carol.succeed("ping -c 1 ${aliceIp6}")
       carol.succeed("ping -c 1 ${bobIp6}")
+      carol.succeed("ping -c 1 ${bobPrefix}::1")
+      carol.succeed("ping -c 8 ${danIp6}")
 
       carol.fail("journalctl -u dhcpcd | grep ygg0")
 
       alice.wait_for_unit("httpd.service")
       carol.succeed("curl --fail -g http://[${aliceIp6}]")
+      carol.succeed("curl --fail -g http://[${danIp6}]")
     '';
 })
diff --git a/nixos/tests/zfs.nix b/nixos/tests/zfs.nix
index 7ba60ee9806c5..87e6c900c98e0 100644
--- a/nixos/tests/zfs.nix
+++ b/nixos/tests/zfs.nix
@@ -46,6 +46,17 @@ let
             "zpool destroy rpool",
             "udevadm settle",
         )
+
+        machine.succeed(
+            'echo password | zpool create -o altroot="/tmp/mnt" '
+            + "-O encryption=aes-256-gcm -O keyformat=passphrase rpool /dev/vdb1",
+            "zfs create -o mountpoint=legacy rpool/root",
+            "mount -t zfs rpool/root /tmp/mnt",
+            "udevadm settle",
+            "umount /tmp/mnt",
+            "zpool destroy rpool",
+            "udevadm settle",
+        )
       '' + extraTest;
 
     };
@@ -57,18 +68,6 @@ in {
 
   unstable = makeZfsTest "unstable" {
     enableUnstable = true;
-    extraTest = ''
-      machine.succeed(
-          'echo password | zpool create -o altroot="/tmp/mnt" '
-          + "-O encryption=aes-256-gcm -O keyformat=passphrase rpool /dev/vdb1",
-          "zfs create -o mountpoint=legacy rpool/root",
-          "mount -t zfs rpool/root /tmp/mnt",
-          "udevadm settle",
-          "umount /tmp/mnt",
-          "zpool destroy rpool",
-          "udevadm settle",
-      )
-    '';
   };
 
   installer = (import ./installer.nix { }).zfsroot;
diff --git a/nixos/tests/zigbee2mqtt.nix b/nixos/tests/zigbee2mqtt.nix
new file mode 100644
index 0000000000000..b7bb21f9227af
--- /dev/null
+++ b/nixos/tests/zigbee2mqtt.nix
@@ -0,0 +1,19 @@
+import ./make-test-python.nix ({ pkgs, ... }:
+
+  {
+    machine = { pkgs, ... }:
+      {
+        services.zigbee2mqtt = {
+          enable = true;
+        };
+      };
+
+    testScript = ''
+      machine.wait_for_unit("zigbee2mqtt.service")
+      machine.wait_until_fails("systemctl status zigbee2mqtt.service")
+      machine.succeed(
+          "journalctl -eu zigbee2mqtt | grep \"Error: Error while opening serialport 'Error: Error: No such file or directory, cannot open /dev/ttyACM0'\""
+      )
+    '';
+  }
+)