diff --git a/lass/2configs/blue-host.nix b/lass/2configs/blue-host.nix
index 6d46cb8c1..fba996743 100644
--- a/lass/2configs/blue-host.nix
+++ b/lass/2configs/blue-host.nix
@@ -99,14 +99,15 @@ in {
   environment.systemPackages = [
     (pkgs.writeDashBin "start-blue" ''
       set -ef
-      if ping -c1 blue.r >/dev/null; then
-        echo 'blue is already running. bailing out'
-        exit 23
-      fi
       if ! $(mount | ${pkgs.gnugrep}/bin/grep -qi '^encfs on /var/lib/containers/blue'); then
         ${pkgs.encfs}/bin/encfs --public /var/lib/containers/.blue /var/lib/containers/blue
       fi
       nixos-container start blue
+      nixos-container run blue -- nixos-rebuild -I /var/src dry-build
+      if ping -c1 blue.r >/dev/null; then
+        echo 'blue is already running. bailing out'
+        exit 23
+      fi
       nixos-container run blue -- nixos-rebuild -I /var/src switch
     '')
   ];