{ config, lib, ... }: {
  nix.buildMachines = let
    base = [ "nixos-test" "benchmark" "big-parallel" "kvm" ];
  in [
    {
      hostName = "localhost";
      protocol = null;
      maxJobs = 0;
      speedFactor = 0;
      systems = [ "x86_64-linux" ];
      supportedFeatures = base;
    }
    {
      hostName = "integra.kyouma.net";
      sshUser = "nix-ssh";
      maxJobs = 2;
      speedFactor = 4;
      systems = [ "aarch64-linux" ];
      supportedFeatures = base;
      sshKey = config.sops.secrets."services/hydra/id_ed25519_hydra".path;
    }
    {
      hostName = "schrodinger.kyouma.net";
      sshUser = "root";
      maxJobs = 2;
      speedFactor = 20;
      systems = [ "riscv64-linux" ];
      supportedFeatures = base ++ [ "gccarch-rv64imac" "gccarch-rv64imacfd" ];
      sshKey = config.sops.secrets."services/hydra/id_ed25519_hydra".path;
    }
  ] ++ lib.forEach (lib.genList (i: i + 1) 8) (num: {
      hostName = "build-worker-0${toString num}";
      sshUser = "root";
      maxJobs = 2;
      speedFactor = 20;
      systems = [ "i686-linux" "x86_64-linux" ];
      supportedFeatures = [ "nixos-test" "benchmark" "big-parallel" "gccarch-x86-64" "gccarch-x86-64-v2" "gccarch-x86-64-v3" ];
      sshKey = config.sops.secrets."services/hydra/id_ed25519_hydra".path;
  });
  nix.distributedBuilds = true;
  nixpkgs.config.allowUnsupportedSystem = true;
  nix.gc = {
    dates = "monthly";
    options = lib.mkForce "--delete-older-than 90d";
  };
  nix.settings = {
    allowed-uris = [
      "github:"
      "git+https://"
      "git+ssh://"
      "https://"
    ];
  };
  programs.ssh = {
    knownHosts = {
      "build-worker-03.nyantec.com".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIEGqTY74c5g15DSNPNM2Wdr5jAwS7BFgX1XRnhtGOnJc";
      "build-worker-04.nyantec.com".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAICOq+5I+nlAN2lJoOtoXrYEDuZ/TMPMa43pIlablYigK";
      "integra.kyouma.net".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIIBwEQiSfaDrUAwgul4mktusBPcIVxI4pLNDh9DPopVU";
      "schrodinger.kyouma.net".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIKo7vZ6lS1wx76YsbAdhOsGcc20YMAW52ep8SZ/FCHDp";
      "localhost".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPNVavo3YHVsrYwXRVISu7kDoknn+5inFGySn4azlB8P";
      "[build-worker-kyoumanet.fly.dev]:2201".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIDL2M97UBHg9aUfjDUxzmzg1r0ga0m3/stummBVwuEAB";
      "[build-worker-kyoumanet.fly.dev]:2202".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOTwVKL0P0chPM2Gz23rbT94844+w1CGJdCaZdzfjThz";
      "[build-worker-kyoumanet.fly.dev]:2203".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIAjy2eZGJQeAYy0+fLgW9jiS0jVY2LInY0NDMnzCvvKp";
      "[build-worker-kyoumanet.fly.dev]:2204".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIN72OyD9LYy4hq0WZ7ie5RPV+G54UreEJiA/RubjGoe9";
      "[build-worker-kyoumanet.fly.dev]:2205".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAICNh1o1I98XrI2XmOI6Q0aHPfyLCIQwKkKOxGUUeXL9v";
      "[build-worker-kyoumanet.fly.dev]:2206".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGf0kxGgwOG9KhUhvxxTSiQC5YikrzZXKDgSpBw33qN4";
      "[build-worker-kyoumanet.fly.dev]:2207".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIL9z95a6Fn/dB+iNigEYpuJdBnBwCkIZYaKHcFbGP+RY";
      "[build-worker-kyoumanet.fly.dev]:2208".publicKey = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIAk+FNMhTfAVqk3MfLp4QiG/i5ti53DlpnC0q+sOvU9O";
    }; 
    extraConfig = lib.concatLines (lib.genList (i: ''
      Host build-worker-0${toString (i + 1)}
        Hostname build-worker-kyoumanet.fly.dev
        Port 220${toString (i + 1)}
    '') 8);
  };
}