diff --git a/staging/src/k8s.io/cloud-provider/cloud.go b/staging/src/k8s.io/cloud-provider/cloud.go
index 6db0219520b..5da25c1f27d 100644
--- a/staging/src/k8s.io/cloud-provider/cloud.go
+++ b/staging/src/k8s.io/cloud-provider/cloud.go
@@ -199,9 +199,10 @@ type Routes interface {
 }
 
 var (
-	InstanceNotFound = errors.New("instance not found")
-	DiskNotFound     = errors.New("disk is not found")
-	NotImplemented   = errors.New("unimplemented")
+	InstanceNotFound     = errors.New("instance not found")
+	DiskNotFound         = errors.New("disk is not found")
+	NotImplemented       = errors.New("unimplemented")
+	ImplementedElsewhere = errors.New("Implemented by a different controller")
 )
 
 // Zone represents the location of a particular machine.