disable gce service handling if has rbs forwarding rule

staging/src/k8s.io/legacy-cloud-providers/gce/gce_loadbalancer_external.go

@@ -62,6 +62,10 @@ func (g *Cloud) ensureExternalLoadBalancer(clusterName string, clusterID string,
 	if hasFinalizer(apiService, ELBRbsFinalizer) {
 		return nil, cloudprovider.ImplementedElsewhere
 	}
+	// Skip service handling if it has Regional Backend Service created by Ingress-GCE
+	if existingFwdRule != nil && existingFwdRule.BackendService != "" {
+		return nil, cloudprovider.ImplementedElsewhere
+	}
 
 	if len(nodes) == 0 {
 		return nil, fmt.Errorf(errStrLbNoHosts)