configuration.nix

{config, pkgs, ...}:

let
  unstable_pkgs = import (pkgs.fetchFromGitHub {
    owner = "NixOS";
    repo = "nixpkgs";
    rev = "a20a20f1363246000307e6dfeaf16d49daa4e06a";
    sha256 = "06n770ia7s8wj7niisf9sazgq4g4q1sw5f8ah65h56k67dpdnpfq";
  }) {};
in
{
  nixpkgs.config.packageOverrides = pkgs: rec {
    consul-ui = unstable_pkgs.consul-ui;
    consul-alerts = unstable_pkgs.consul-alerts;
    consul-template = unstable_pkgs.consul-template;
    consul = unstable_pkgs.consul;
  };

  environment.systemPackages = with pkgs; [
    consul-ui
    consul-alerts
    consul-template
    consul
  ];
  
  # more config ...
  
}