{ pkgs, config, ... }: {
  services.hydra = {
    enable = true;
    hydraURL = "https://hydra.${config.networking.domain}"; # externally visible URL
    notificationSender = "hydra@localhost"; #
    # a standalone hydra will require you to unset the buildMachinesFiles list to avoid using a nonexistant /etc/nix/machines
    buildMachinesFiles = [ ];
    # you will probably also want, otherwise *everything* will be built from scratch
    useSubstitutes = true;
    port = 6732;
  };

  networking.firewall = {
    allowedTCPPorts = [ config.services.hydra.port ];
    allowedUDPPorts = [ config.services.hydra.port ];
  };


}