.files/nix/configurations/hetzner_benchmark/nixos/builder.nix

# https://nix.dev/tutorials/nixos/distributed-builds-setup.html
{ config, ... }:
{
  users.users.remotebuild = {
    isSystemUser = true;
    group = "remotebuild";
    useDefaultShell = true;

    openssh.authorizedKeys.keys = config.users.users.root.openssh.authorizedKeys.keys;
  };

  users.groups.remotebuild = { };
  nix = {
    nrBuildUsers = 64; # defaults to 32
    settings = {
      trusted-users = [ "remotebuild" ];

      min-free = 50 * 1024 * 1024 * 1024; # start gc when < 10 GB is available
      max-free = 100 * 1024 * 1024 * 1024; # stop gc when 20 GB is available

      max-jobs = "auto";
      cores = 0;
    };
  };

  systemd.services.nix-daemon.serviceConfig = {
    MemoryAccounting = true;
    MemoryMax = "90%";
    OOMScoreAdjust = 500;
  };
}