diff --git a/docker/services/ceilometer-agent-notification.yaml b/docker/services/ceilometer-agent-notification.yaml
index 3e18c02a93..1d6d501b78 100644
--- a/docker/services/ceilometer-agent-notification.yaml
+++ b/docker/services/ceilometer-agent-notification.yaml
@@ -83,17 +83,19 @@ outputs:
         /var/lib/kolla/config_files/ceilometer_agent_notification.json:
           command: /usr/bin/ceilometer-agent-notification --logfile /var/log/ceilometer/agent-notification.log
           config_files:
-            - source: "/var/lib/kolla/config_files/src/*"
-              dest: "/"
-              merge: true
-              preserve_properties: true
-            - if:
-                - ceilometer_enable_panko
-                - source: "/var/lib/kolla/config_files/src-panko/*"
+            list_concat:
+              - - source: "/var/lib/kolla/config_files/src/*"
                   dest: "/"
                   merge: true
                   preserve_properties: true
-                - ''
+              - if:
+                  - ceilometer_enable_panko
+                  - - source: "/var/lib/kolla/config_files/src-panko/*"
+                      dest: "/"
+                      merge: true
+                      preserve_properties: true
+                  - null
+
           permissions:
             - path: /etc/panko
               owner: root:ceilometer