diff --git a/trigger/pubsub/util.go b/trigger/pubsub/util.go
index 24943713..bb897bc4 100644
--- a/trigger/pubsub/util.go
+++ b/trigger/pubsub/util.go
@@ -9,7 +9,7 @@ import (
 )
 
 // MetadataEndpoint - default metadata server for gcloud pubsub
-const MetadataEndpoint = "metadata/computeMetadata/v1/instance/attributes/cluster-name"
+const MetadataEndpoint = "http://metadata/computeMetadata/v1/instance/attributes/cluster-name"
 
 func containerRegistryURI(projectID, registry string) string {
 	return registry + "%2F" + projectID