nixos-servers/nixos/modules/disko.nix

{ lib, config, ... }:
let cfg = config.lab.disko;
in {
  options.lab.disko.osDiskDevice = lib.mkOption {
    type = lib.types.str;
    description = ''
      The disk device to be used for the operating system.
    '';
  };

  # TODO: rename this to 'osDisk'. Unfortunately, we would need to run nixos-anywhere again then
  config.disko.devices.disk.vdb = {
    device = cfg.osDiskDevice;
    type = "disk";
    content = {
      type = "gpt";
      partitions = {
        ESP = {
          type = "EF00";
          size = "500M";
          content = {
            type = "filesystem";
            format = "vfat";
            mountpoint = "/boot";
          };
        };
        root = {
          end = "-4G";
          content = {
            type = "filesystem";
            format = "btrfs";
            mountpoint = "/";
          };
        };
        swap = { size = "100%"; };
      };
    };
  };
}