diff --git a/log.graphqls b/log.graphqls
index 6781f9b..855f6db 100644
--- a/log.graphqls
+++ b/log.graphqls
@@ -16,6 +16,9 @@
 
 # The list of logs
 type Logs {
+    # When this field is not empty, frontend should display it in UI
+    errorReason: String
+
     logs: [Log!]!
 }
 
diff --git a/ondemand-pod-log.graphqls b/ondemand-pod-log.graphqls
index a98baf9..0df1e96 100644
--- a/ondemand-pod-log.graphqls
+++ b/ondemand-pod-log.graphqls
@@ -34,7 +34,14 @@ input OndemandContainergQueryCondition {
     serviceInstanceId: ID
 }
 
+type PodContainers {
+    # When this field is not empty, frontend should display it in UI
+    errorReason: String
+
+    containers: [String!]!
+}
+
 extend type Query {
-    listContainers(condition: OndemandContainergQueryCondition): [String!]!
+    listContainers(condition: OndemandContainergQueryCondition): PodContainers
     ondemandPodLogs(condition: OndemandLogQueryCondition): Logs
 }