nixpkgs/nixos/tests/systemd-resolved.nix

import ./make-test-python.nix ({ pkgs, lib, ... }: {
  name = "systemd-resolved";
  meta.maintainers = [ lib.maintainers.elvishjerricco ];

  nodes.server = { lib, config, ... }: let
    exampleZone = pkgs.writeTextDir "example.com.zone" ''
      @ SOA ns.example.com. noc.example.com. 2019031301 86400 7200 3600000 172800
      @       A       ${(lib.head config.networking.interfaces.eth1.ipv4.addresses).address}
      @       AAAA    ${(lib.head config.networking.interfaces.eth1.ipv6.addresses).address}
    '';
  in {
    networking.firewall.enable = false;
    networking.useDHCP = false;

    networking.interfaces.eth1.ipv6.addresses = lib.mkForce [
      { address = "fd00::1"; prefixLength = 64; }
    ];

    services.knot = {
      enable = true;
      settings = {
        server.listen = [
          "0.0.0.0@53"
          "::@53"
        ];
        template.default.storage = exampleZone;
        zone."example.com".file = "example.com.zone";
      };
    };
  };

  nodes.client = { nodes, ... }: let
    inherit (lib.head nodes.server.networking.interfaces.eth1.ipv4.addresses) address;
  in {
    networking.nameservers = [ address ];
    networking.interfaces.eth1.ipv6.addresses = lib.mkForce [
      { address = "fd00::2"; prefixLength = 64; }
    ];
    services.resolved.enable = true;
    services.resolved.fallbackDns = [ ];
    networking.useNetworkd = true;
    networking.useDHCP = false;
    systemd.network.networks."40-eth0".enable = false;

    testing.initrdBackdoor = true;
    boot.initrd = {
      systemd.enable = true;
      systemd.initrdBin = [ pkgs.iputils ];
      network.enable = true;
      services.resolved.enable = true;
    };
  };

  testScript = { nodes, ... }: let
    address4 = (lib.head nodes.server.networking.interfaces.eth1.ipv4.addresses).address;
    address6 = (lib.head nodes.server.networking.interfaces.eth1.ipv6.addresses).address;
  in ''
    start_all()
    server.wait_for_unit("multi-user.target")

    def test_client():
        query = client.succeed("resolvectl query example.com")
        assert "${address4}" in query
        assert "${address6}" in query
        client.succeed("ping -4 -c 1 example.com")
        client.succeed("ping -6 -c 1 example.com")

    client.wait_for_unit("initrd.target")
    test_client()
    client.switch_root()

    client.wait_for_unit("multi-user.target")
    test_client()
  '';
})