diff --git a/krebs/3modules/lass/default.nix b/krebs/3modules/lass/default.nix
index d86c00563..498282b03 100644
--- a/krebs/3modules/lass/default.nix
+++ b/krebs/3modules/lass/default.nix
@@ -9,6 +9,7 @@ let
     "test-centos7"
   ] (name: {
     inherit name;
+    cores = 1;
     nets = {
       retiolum = {
         addrs4 = ["10.243.111.111"];