diff options
Diffstat (limited to 'nixpkgs/nixos/modules/virtualisation/amazon-init.nix')
-rw-r--r-- | nixpkgs/nixos/modules/virtualisation/amazon-init.nix | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/nixpkgs/nixos/modules/virtualisation/amazon-init.nix b/nixpkgs/nixos/modules/virtualisation/amazon-init.nix new file mode 100644 index 000000000000..8032b2c6d7ca --- /dev/null +++ b/nixpkgs/nixos/modules/virtualisation/amazon-init.nix @@ -0,0 +1,61 @@ +{ config, pkgs, ... }: + +let + script = '' + #!${pkgs.runtimeShell} -eu + + echo "attempting to fetch configuration from EC2 user data..." + + export HOME=/root + export PATH=${pkgs.lib.makeBinPath [ config.nix.package pkgs.systemd pkgs.gnugrep pkgs.gnused config.system.build.nixos-rebuild]}:$PATH + export NIX_PATH=/nix/var/nix/profiles/per-user/root/channels/nixos:nixos-config=/etc/nixos/configuration.nix:/nix/var/nix/profiles/per-user/root/channels + + userData=/etc/ec2-metadata/user-data + + if [ -s "$userData" ]; then + # If the user-data looks like it could be a nix expression, + # copy it over. Also, look for a magic three-hash comment and set + # that as the channel. + if sed '/^\(#\|SSH_HOST_.*\)/d' < "$userData" | grep -q '\S'; then + channels="$(grep '^###' "$userData" | sed 's|###\s*||')" + printf "%s" "$channels" | while read channel; do + echo "writing channel: $channel" + done + + if [[ -n "$channels" ]]; then + printf "%s" "$channels" > /root/.nix-channels + nix-channel --update + fi + + echo "setting configuration from EC2 user data" + cp "$userData" /etc/nixos/configuration.nix + else + echo "user data does not appear to be a Nix expression; ignoring" + exit + fi + else + echo "no user data is available" + exit + fi + + nixos-rebuild switch + ''; +in { + systemd.services.amazon-init = { + inherit script; + description = "Reconfigure the system from EC2 userdata on startup"; + + wantedBy = [ "multi-user.target" ]; + after = [ "multi-user.target" ]; + requires = [ "network-online.target" ]; + + restartIfChanged = false; + unitConfig.X-StopOnRemoval = false; + + serviceConfig = { + Type = "oneshot"; + RemainAfterExit = true; + }; + }; +} + |