simple-nixos-fediverse/installer.nix

/**
  Convert a NixOS configuration to one for a minimal installer ISO

  WARNING: Running this installer will format the target disk!
*/
nixpkgs: machine:
  let
    installer = { config, pkgs, lib, ... }:
      let
        bootstrap = pkgs.writeShellApplication {
          name = "bootstrap";
          runtimeInputs = with pkgs; [ nixos-install-tools ];
          text = ''
            ${machine.config.system.build.diskoScript}
            nixos-install --no-root-password --no-channel-copy --system ${machine.config.system.build.toplevel} \
              && poweroff
          '';
        };
      in
      {
        imports = [
          "${nixpkgs}/nixos/modules/installer/cd-dvd/installation-cd-minimal.nix"
        ];
        nixpkgs.hostPlatform = "x86_64-linux";
        services.getty.autologinUser = lib.mkForce "root";
        programs.bash.loginShellInit = ''
          ${nixpkgs.lib.getExe bootstrap}
        '';

        isoImage = {
          compressImage = false;
          squashfsCompression = "lz4";
          isoName = lib.mkForce "installer.iso";
          ## ^^ FIXME: Use a more interesting name or keep the default name and
          ## use `isoImage.isoName` in the tests.
        };
      };
  in
  (nixpkgs.lib.nixosSystem { modules =  [installer];}).config.system.build.isoImage