add external cloudprovider to clerly denote the offloading off cloudprovider tasks

cmd/kubelet/app/server.go

@@ -420,7 +420,7 @@ func run(s *options.KubeletServer, kubeDeps *kubelet.KubeletDeps) (err error) {
 		var externalKubeClient clientgoclientset.Interface
 		var cloud cloudprovider.Interface
 
-		if s.CloudProvider != componentconfigv1alpha1.AutoDetectCloudProvider {
+		if !cloudprovider.IsExternal(s.CloudProvider) && s.CloudProvider != componentconfigv1alpha1.AutoDetectCloudProvider {
 			cloud, err = cloudprovider.InitCloudProvider(s.CloudProvider, s.CloudConfigFile)
 			if err != nil {
 				return err

pkg/cloudprovider/plugins.go

@@ -37,6 +37,8 @@ var (
 	providers      = make(map[string]Factory)
 )
 
+const externalCloudProvider = "external"
+
 // RegisterCloudProvider registers a cloudprovider.Factory by name.  This
 // is expected to happen during app startup.
 func RegisterCloudProvider(name string, cloud Factory) {
@@ -85,6 +87,11 @@ func GetCloudProvider(name string, config io.Reader) (Interface, error) {
 	return f(config)
 }
 
+// Detects if the string is an external cloud provider
+func IsExternal(name string) bool {
+	return name == externalCloudProvider
+}
+
 // InitCloudProvider creates an instance of the named cloud provider.
 func InitCloudProvider(name string, configFilePath string) (Interface, error) {
 	var cloud Interface
@@ -95,6 +102,11 @@ func InitCloudProvider(name string, configFilePath string) (Interface, error) {
 		return nil, nil
 	}
 
+	if IsExternal(name) {
+		glog.Info("External cloud provider specified")
+		return nil, nil
+	}
+
 	if configFilePath != "" {
 		var config *os.File
 		config, err = os.Open(configFilePath)