diff --git a/roles/ceph-validate/tasks/main.yml b/roles/ceph-validate/tasks/main.yml
index ccbbdfe28..47233f588 100644
--- a/roles/ceph-validate/tasks/main.yml
+++ b/roles/ceph-validate/tasks/main.yml
@@ -208,7 +208,7 @@
   when:
     - ceph_docker_registry_auth | bool
     - (ceph_docker_registry_username is not defined or ceph_docker_registry_password is not defined) or
-      (ceph_docker_registry_username | length == 0 or ceph_docker_registry_password | length == 0)
+      (ceph_docker_registry_username | string | length == 0 or ceph_docker_registry_password | string | length == 0)
 
 - name: validate container service and container package
   fail: