diff --git a/site.yml b/site.yml
index d95d1e6..c6147fe 100644
--- a/site.yml
+++ b/site.yml
@@ -9,5 +9,5 @@
     - role: common
       tags: ['common']
     - role: docker
-      when: docker
+      when: docker is defined
       tags: ['docker']