diff --git a/tripleo_common/utils/plan.py b/tripleo_common/utils/plan.py
index 19d70e553..af5da200b 100644
--- a/tripleo_common/utils/plan.py
+++ b/tripleo_common/utils/plan.py
@@ -120,7 +120,8 @@ def rotate_fernet_keys(heat,
         stack_env = heat.stacks.environment(
             stack_id=container)
     except heat_exc.HTTPNotFound:
-        stack_env = None
+        raise RuntimeError('Can not rotate fernet keys without an'
+                           'existing stack %s.' % container)
 
     parameter_defaults = stack_env.get('parameter_defaults', {})
     passwords = get_overriden_passwords({}, parameter_defaults)