diff options
Diffstat (limited to 'nixos/modules/virtualisation/ec2-metadata-fetcher.sh')
-rw-r--r-- | nixos/modules/virtualisation/ec2-metadata-fetcher.sh | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/nixos/modules/virtualisation/ec2-metadata-fetcher.sh b/nixos/modules/virtualisation/ec2-metadata-fetcher.sh new file mode 100644 index 0000000000000..9e204d45dbd83 --- /dev/null +++ b/nixos/modules/virtualisation/ec2-metadata-fetcher.sh @@ -0,0 +1,67 @@ +metaDir=/etc/ec2-metadata +mkdir -m 0755 -p "$metaDir" +rm -f "$metaDir/*" + +get_imds_token() { + # retry-delay of 1 selected to give the system a second to get going, + # but not add a lot to the bootup time + curl \ + --silent \ + --show-error \ + --retry 3 \ + --retry-delay 1 \ + --fail \ + -X PUT \ + --connect-timeout 1 \ + -H "X-aws-ec2-metadata-token-ttl-seconds: 600" \ + http://169.254.169.254/latest/api/token +} + +preflight_imds_token() { + # retry-delay of 1 selected to give the system a second to get going, + # but not add a lot to the bootup time + curl \ + --silent \ + --show-error \ + --retry 3 \ + --retry-delay 1 \ + --fail \ + --connect-timeout 1 \ + -H "X-aws-ec2-metadata-token: $IMDS_TOKEN" \ + -o /dev/null \ + http://169.254.169.254/1.0/meta-data/instance-id +} + +try=1 +while [ $try -le 3 ]; do + echo "(attempt $try/3) getting an EC2 instance metadata service v2 token..." + IMDS_TOKEN=$(get_imds_token) && break + try=$((try + 1)) + sleep 1 +done + +if [ "x$IMDS_TOKEN" == "x" ]; then + echo "failed to fetch an IMDS2v token." +fi + +try=1 +while [ $try -le 10 ]; do + echo "(attempt $try/10) validating the EC2 instance metadata service v2 token..." + preflight_imds_token && break + try=$((try + 1)) + sleep 1 +done + +echo "getting EC2 instance metadata..." + +get_imds() { + # Intentionally no --fail here, so that we proceed even if e.g. a + # 404 was returned (but we still fail if we can't reach the IMDS + # server). + curl --silent --show-error --header "X-aws-ec2-metadata-token: $IMDS_TOKEN" "$@" +} + +get_imds -o "$metaDir/ami-manifest-path" http://169.254.169.254/1.0/meta-data/ami-manifest-path +(umask 077 && get_imds -o "$metaDir/user-data" http://169.254.169.254/1.0/user-data) +get_imds -o "$metaDir/hostname" http://169.254.169.254/1.0/meta-data/hostname +get_imds -o "$metaDir/public-keys-0-openssh-key" http://169.254.169.254/1.0/meta-data/public-keys/0/openssh-key |