blob: 028a2d74041e6580482036242fb4d20dd96e30c4 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
# This module creates netboot media containing the given NixOS
# configuration.
{ config, lib, pkgs, ... }:
with lib;
{
options = {
netboot.squashfsCompression = mkOption {
default = with pkgs.stdenv.hostPlatform; "xz -Xdict-size 100% "
+ lib.optionalString isx86 "-Xbcj x86"
# Untested but should also reduce size for these platforms
+ lib.optionalString isAarch "-Xbcj arm"
+ lib.optionalString (isPower && is32bit && isBigEndian) "-Xbcj powerpc"
+ lib.optionalString (isSparc) "-Xbcj sparc";
description = lib.mdDoc ''
Compression settings to use for the squashfs nix store.
'';
example = "zstd -Xcompression-level 6";
type = types.str;
};
netboot.storeContents = mkOption {
example = literalExpression "[ pkgs.stdenv ]";
description = lib.mdDoc ''
This option lists additional derivations to be included in the
Nix store in the generated netboot image.
'';
};
};
config = {
# Don't build the GRUB menu builder script, since we don't need it
# here and it causes a cyclic dependency.
boot.loader.grub.enable = false;
# !!! Hack - attributes expected by other modules.
environment.systemPackages = [ pkgs.grub2_efi ]
++ (lib.optionals (pkgs.stdenv.hostPlatform.system != "aarch64-linux") [pkgs.grub2 pkgs.syslinux]);
fileSystems."/" = mkImageMediaOverride
{ fsType = "tmpfs";
options = [ "mode=0755" ];
};
# In stage 1, mount a tmpfs on top of /nix/store (the squashfs
# image) to make this a live CD.
fileSystems."/nix/.ro-store" = mkImageMediaOverride
{ fsType = "squashfs";
device = "../nix-store.squashfs";
options = [ "loop" ];
neededForBoot = true;
};
fileSystems."/nix/.rw-store" = mkImageMediaOverride
{ fsType = "tmpfs";
options = [ "mode=0755" ];
neededForBoot = true;
};
fileSystems."/nix/store" = mkImageMediaOverride
{ overlay = {
lowerdir = [ "/nix/.ro-store" ];
upperdir = "/nix/.rw-store/store";
workdir = "/nix/.rw-store/work";
};
neededForBoot = true;
};
boot.initrd.availableKernelModules = [ "squashfs" "overlay" ];
boot.initrd.kernelModules = [ "loop" "overlay" ];
# Closures to be copied to the Nix store, namely the init
# script and the top-level system configuration directory.
netboot.storeContents =
[ config.system.build.toplevel ];
# Create the squashfs image that contains the Nix store.
system.build.squashfsStore = pkgs.callPackage ../../../lib/make-squashfs.nix {
storeContents = config.netboot.storeContents;
comp = config.netboot.squashfsCompression;
};
# Create the initrd
system.build.netbootRamdisk = pkgs.makeInitrdNG {
inherit (config.boot.initrd) compressor;
prepend = [ "${config.system.build.initialRamdisk}/initrd" ];
contents =
[ { object = config.system.build.squashfsStore;
symlink = "/nix-store.squashfs";
}
];
};
system.build.netbootIpxeScript = pkgs.writeTextDir "netboot.ipxe" ''
#!ipxe
# Use the cmdline variable to allow the user to specify custom kernel params
# when chainloading this script from other iPXE scripts like netboot.xyz
kernel ${pkgs.stdenv.hostPlatform.linux-kernel.target} init=${config.system.build.toplevel}/init initrd=initrd ${toString config.boot.kernelParams} ''${cmdline}
initrd initrd
boot
'';
# A script invoking kexec on ./bzImage and ./initrd.gz.
# Usually used through system.build.kexecTree, but exposed here for composability.
system.build.kexecScript = pkgs.writeScript "kexec-boot" ''
#!/usr/bin/env bash
if ! kexec -v >/dev/null 2>&1; then
echo "kexec not found: please install kexec-tools" 2>&1
exit 1
fi
SCRIPT_DIR=$( cd -- "$( dirname -- "''${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
kexec --load ''${SCRIPT_DIR}/bzImage \
--initrd=''${SCRIPT_DIR}/initrd.gz \
--command-line "init=${config.system.build.toplevel}/init ${toString config.boot.kernelParams}"
kexec -e
'';
# A tree containing initrd.gz, bzImage and a kexec-boot script.
system.build.kexecTree = pkgs.linkFarm "kexec-tree" [
{
name = "initrd.gz";
path = "${config.system.build.netbootRamdisk}/initrd";
}
{
name = "bzImage";
path = "${config.system.build.kernel}/${config.system.boot.loader.kernelFile}";
}
{
name = "kexec-boot";
path = config.system.build.kexecScript;
}
];
boot.loader.timeout = 10;
boot.postBootCommands =
''
# After booting, register the contents of the Nix store
# in the Nix database in the tmpfs.
${config.nix.package}/bin/nix-store --load-db < /nix/store/nix-path-registration
# nixos-rebuild also requires a "system" profile and an
# /etc/NIXOS tag.
touch /etc/NIXOS
${config.nix.package}/bin/nix-env -p /nix/var/nix/profiles/system --set /run/current-system
'';
};
}
|
