_:

{
  nix = {
    buildMachines = [
      {
        hostName = "marvin";
        systems = [
          "x86_64-linux"
          "i686-linux"
        ];
        protocol = "ssh";
        maxJobs = 8;
        speedFactor = 3;
        supportedFeatures = [
          "nixos-test"
          "benchmark"
          "big-parallel"
          "kvm"
        ];
        mandatoryFeatures = [ ];
        sshUser = "thehedgehog";
      }
    ];
    distributedBuilds = true;
    settings = {
      builders-use-substitutes = true;
      trusted-public-keys = [ "marvin:6KYRoivyUqnmakGGMyvPOlJfLbIMixVFCFH25260vFc=" ];
      substituters = [ "ssh://thehedgehog@marvin" ];
    };
  };
}