diff --git a/servers.nix b/servers.nix
index a1e7ddc..7dd2986 100644
--- a/servers.nix
+++ b/servers.nix
@@ -1,24 +1,10 @@
 let
-  lib = import <nixpkgs/lib>;
-  n = url: conf: let
-    c = import "${url}/nixos/lib/eval-config.nix" {
-      modules = [ ./roles conf ];
-      extraArgs.name = lib.removeSuffix ".nix" (builtins.baseNameOf conf);
-      extraArgs.nixpkgs = url;
-    };
-  in c.config.system.build // c;
-  git = n "https://github.com/NixOS/nixpkgs/archive/master.tar.gz";
-  stable = n (builtins.fetchTarball "channel:nixos-20.03");
-  unstable = n (builtins.fetchTarball "channel:nixos-unstable-small");
-  checkout = n ../projects/nixpkgs;
-  channel = n "/nix/var/nix/profiles/per-user/root/channels/nixos";
+  sources = import ./nix/sources.nix;
+  nixpkgs = import sources.nixpkgs {};
+  nixos = name: configuration: import (nixpkgs.path + "/nixos/lib/eval-config.nix") {
+    extraArgs = { inherit name; };
+    modules = [ ({lib, ... }: { config.nixpkgs.pkgs = lib.mkDefault nixpkgs; }) ] ++ configuration;
+  };
+  names = [ "pennyworth" "jarvis" "blackadder" "woodhouse" "frumar" "zazu" ];
 in
-{
-  pennyworth = (unstable ./logical/pennyworth.nix).toplevel;
-  jarvis     = (channel ./logical/jarvis.nix).toplevel;
-  blackadder = (channel ./logical/blackadder.nix).toplevel;
-  ascanius   = (channel ./logical/ascanius.nix).toplevel;
-  woodhouse  = (channel ./logical/woodhouse.nix).toplevel; # 192.168.178.39
-  frumar     = (channel ./logical/frumar.nix).toplevel; # frumar.local
-  zazu       = (stable ./logical/zazu.nix).toplevel;
-}
+nixpkgs.lib.genAttrs names (name: (nixos name [ ./roles (./logical + "/${name}.nix") ]).config.system.build.toplevel)