systemd-initrd-luks-keyfile.nix

import ./make-test-python.nix (
  { lib, pkgs, ... }:
  let

    keyfile = pkgs.writeText "luks-keyfile" ''
      MIGHAoGBAJ4rGTSo/ldyjQypd0kuS7k2OSsmQYzMH6TNj3nQ/vIUjDn7fqa3slt2
      gV6EK3TmTbGc4tzC1v4SWx2m+2Bjdtn4Fs4wiBwn1lbRdC6i5ZYCqasTWIntWn+6
      FllUkMD5oqjOR/YcboxG8Z3B5sJuvTP9llsF+gnuveWih9dpbBr7AgEC
    '';

  in
  {
    name = "systemd-initrd-luks-keyfile";

    nodes.machine =
      { pkgs, ... }:
      {
        # Use systemd-boot
        virtualisation = {
          emptyDiskImages = [ 512 ];
          useBootLoader = true;
          # Necessary to boot off the encrypted disk because it requires a init script coming from the Nix store
          mountHostNixStore = true;
          useEFIBoot = true;
        };
        boot.loader.systemd-boot.enable = true;

        environment.systemPackages = with pkgs; [ cryptsetup ];
        boot.initrd.systemd = {
          enable = true;
          emergencyAccess = true;
        };

        specialisation.boot-luks.configuration = {
          boot.initrd.luks.devices = lib.mkVMOverride {
            cryptroot = {
              device = "/dev/vdb";
              keyFile = "/etc/cryptroot.key";
            };
          };
          virtualisation.rootDevice = "/dev/mapper/cryptroot";
          virtualisation.fileSystems."/".autoFormat = true;
          boot.initrd.secrets."/etc/cryptroot.key" = keyfile;
        };
      };

    testScript = ''
      # Create encrypted volume
      machine.wait_for_unit("multi-user.target")
      machine.succeed("cryptsetup luksFormat -q --iter-time=1 -d ${keyfile} /dev/vdb")

      # Boot from the encrypted disk
      machine.succeed("bootctl set-default nixos-generation-1-specialisation-boot-luks.conf")
      machine.succeed("sync")
      machine.crash()

      # Boot and decrypt the disk
      machine.wait_for_unit("multi-user.target")
      assert "/dev/mapper/cryptroot on / type ext4" in machine.succeed("mount")
    '';
  }
)