diff --git a/metropolis/node/kubernetes/csi.go b/metropolis/node/kubernetes/csi.go
index be9e3f5..92c700e 100644
--- a/metropolis/node/kubernetes/csi.go
+++ b/metropolis/node/kubernetes/csi.go
@@ -266,6 +266,8 @@
 // in Kubelet which requires it to remove and recreate its gRPC socket for
 // every new registration attempt.
 type pluginRegistrationServer struct {
+	pluginregistration.UnimplementedRegistrationServer
+
 	// regErr has a buffer of 1, so that at least one error can always be
 	// sent into it in a non-blocking way. There is a race if
 	// NotifyRegistrationStatus is called twice with an error as the buffered