diff --git a/tasks/persistent_cloud.yml b/tasks/persistent_cloud.yml
index eaf9a8cd0f..691862519c 100644
--- a/tasks/persistent_cloud.yml
+++ b/tasks/persistent_cloud.yml
@@ -21,4 +21,4 @@
 - name: attach volumes to the system
   local_action: shell euca-attach-volume --config ${persist_config} -i ${inst_res.instances[0].id} $item
   with_items: $volumes
-  only_if: "'$volumes' and '${host_is_up.rc}' != '0'"
+  only_if: 'is_set("${volumes}") and "${host_is_up.rc}" != "0"'