diff --git a/ops/exports.nix b/ops/exports.nix
new file mode 100644
index 0000000..3356607
--- /dev/null
+++ b/ops/exports.nix
@@ -0,0 +1,14 @@
+{ hscloud, pkgs, hscloudForPkgs, ... }:
+
+{
+  # Used by clustercfg to figure out which machines need kube certs.
+  kubeMachineNames = let
+    isKubeMachine = n: value:
+      n != "__readTree" &&
+      (builtins.hasAttr "hscloud" value.options) &&
+      (builtins.hasAttr "kube" value.options.hscloud) &&
+      value.options.hscloud.kube.control.enable.value;
+    machines = pkgs.lib.filterAttrs isKubeMachine hscloud.ops.machines;
+    names = pkgs.lib.mapAttrsToList (name: _: name) machines;
+  in names;
+}