{ lib, pkgs, ... }: {
  nix.gc.options = lib.mkForce "--delete-older-than 60d";
  nix.settings.trusted-users = [ "build" ];
  nix.extraOptions = ''
    min-free = ${builtins.toString (4096 * 1024 * 1024)}
    max-free = ${builtins.toString (8192 * 1024 * 1024)}
    max-substitution-jobs = 20
    max-silent-time = 900
  '';
  users.users.build = {
    isNormalUser = true;
    shell = pkgs.bash;
    ignoreShellProgramCheck = true;
    openssh.authorizedKeys.keys = [
      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIA/+iN407+HsfHbbC3tfdA8Yf4TZ08qXQMb4tb/SDAs+ emily@card"
      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIE/vCXM3IaxJP9v2Y+xcQrQD2IcffgdzqtWhpMjj9Xl5 hydra@seras"
      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAICT0dGyLUjxFnvqUmex+5xUGQ7D4yGHKo267JgApcq0k root@ryuuko"
      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIIDTwCSWYODyvTJxwB6Rahuy0j6s/YYwtQta8bjzG/We root@ryuuko-arch"
    ];
  };
}