nix-configuration/modules/roles/server.nix

{
  config,
  lib,
  modulesPath,
  pkgs,
  ...
}:
let
  inherit (config.host) role;
in
with lib;
{
  imports = [ (modulesPath + "/installer/scan/not-detected.nix") ];

  config = mkIf (role == "server") {
    host.apps.tmux.enable = true;
    environment.systemPackages = with pkgs; [
      htop
      mdadm
    ];
  };
}