Allow opting out of automatic cloud provider detection in kubelet

cmd/kubelet/app/options/options.go

@@ -43,6 +43,8 @@ const (
 	// When these values are updated, also update test/e2e/framework/util.go
 	defaultPodInfraContainerImageName    = "gcr.io/google_containers/pause"
 	defaultPodInfraContainerImageVersion = "3.0"
+	// Auto detect cloud provider.
+	AutoDetectCloudProvider = "auto-detect"
 )
 
 // Returns the arch-specific pause image that kubelet should use as the default
@@ -83,6 +85,7 @@ func NewKubeletServer() *KubeletServer {
 			VolumeStatsAggPeriod:         unversioned.Duration{Duration: time.Minute},
 			CertDirectory:                "/var/run/kubernetes",
 			CgroupRoot:                   "",
+			CloudProvider:                AutoDetectCloudProvider,
 			ConfigureCBR0:                false,
 			ContainerRuntime:             "docker",
 			RuntimeRequestTimeout:        unversioned.Duration{Duration: 2 * time.Minute},
@@ -218,7 +221,7 @@ func (s *KubeletServer) AddFlags(fs *pflag.FlagSet) {
 	fs.StringVar(&s.NetworkPluginName, "network-plugin", s.NetworkPluginName, "<Warning: Alpha feature> The name of the network plugin to be invoked for various events in kubelet/pod lifecycle")
 	fs.StringVar(&s.NetworkPluginDir, "network-plugin-dir", s.NetworkPluginDir, "<Warning: Alpha feature> The full path of the directory in which to search for network plugins")
 	fs.StringVar(&s.VolumePluginDir, "volume-plugin-dir", s.VolumePluginDir, "<Warning: Alpha feature> The full path of the directory in which to search for additional third party volume plugins")
-	fs.StringVar(&s.CloudProvider, "cloud-provider", s.CloudProvider, "The provider for cloud services.  Empty string for no provider.")
+	fs.StringVar(&s.CloudProvider, "cloud-provider", s.CloudProvider, "The provider for cloud services. By default, kubelet will attempt to auto-detect the cloud provider. Specify empty string for running with no cloud provider. [default=auto-detect]")
 	fs.StringVar(&s.CloudConfigFile, "cloud-config", s.CloudConfigFile, "The path to the cloud provider configuration file.  Empty string for no configuration file.")
 
 	fs.StringVar(&s.KubeletCgroups, "resource-container", s.KubeletCgroups, "Optional absolute name of the resource-only container to create and run the Kubelet in.")

cmd/kubelet/app/server.go

@@ -339,12 +339,16 @@ func run(s *options.KubeletServer, kcfg *KubeletConfig) (err error) {
 			glog.Warningf("No API client: %v", err)
 		}
 
-		cloud, err := cloudprovider.InitCloudProvider(s.CloudProvider, s.CloudConfigFile)
-		if err != nil {
-			return err
+		if s.CloudProvider == options.AutoDetectCloudProvider {
+			kcfg.AutoDetectCloudProvider = true
+		} else {
+			cloud, err := cloudprovider.InitCloudProvider(s.CloudProvider, s.CloudConfigFile)
+			if err != nil {
+				return err
+			}
+			glog.V(2).Infof("Successfully initialized cloud provider: %q from the config file: %q\n", s.CloudProvider, s.CloudConfigFile)
+			kcfg.Cloud = cloud
 		}
-		glog.V(2).Infof("Successfully initialized cloud provider: %q from the config file: %q\n", s.CloudProvider, s.CloudConfigFile)
-		kcfg.Cloud = cloud
 	}
 
 	if kcfg.CAdvisorInterface == nil {
@@ -773,6 +777,7 @@ type KubeletConfig struct {
 	Address                        net.IP
 	AllowPrivileged                bool
 	Auth                           server.AuthInterface
+	AutoDetectCloudProvider        bool
 	Builder                        KubeletBuilder
 	CAdvisorInterface              cadvisor.Interface
 	VolumeStatsAggPeriod           time.Duration
@@ -920,6 +925,7 @@ func CreateAndInitKubelet(kc *KubeletConfig) (k KubeletBootstrap, pc *config.Pod
 		kc.ImageGCPolicy,
 		kc.DiskSpacePolicy,
 		kc.Cloud,
+		kc.AutoDetectCloudProvider,
 		kc.NodeLabels,
 		kc.NodeStatusUpdateFrequency,
 		kc.OSInterface,

pkg/kubelet/kubelet.go

@@ -201,6 +201,7 @@ func NewMainKubelet(
 	imageGCPolicy ImageGCPolicy,
 	diskSpacePolicy DiskSpacePolicy,
 	cloud cloudprovider.Interface,
+	autoDetectCloudProvider bool,
 	nodeLabels map[string]string,
 	nodeStatusUpdateFrequency time.Duration,
 	osInterface kubecontainer.OSInterface,
@@ -331,9 +332,10 @@ func NewMainKubelet(
 		cadvisor:                       cadvisorInterface,
 		diskSpaceManager:               diskSpaceManager,
 		cloud:                          cloud,
-		nodeRef:                        nodeRef,
-		nodeLabels:                     nodeLabels,
-		nodeStatusUpdateFrequency:      nodeStatusUpdateFrequency,
+		autoDetectCloudProvider:   autoDetectCloudProvider,
+		nodeRef:                   nodeRef,
+		nodeLabels:                nodeLabels,
+		nodeStatusUpdateFrequency: nodeStatusUpdateFrequency,
 		os:                         osInterface,
 		oomWatcher:                 oomWatcher,
 		cgroupRoot:                 cgroupRoot,
@@ -688,7 +690,8 @@ type Kubelet struct {
 	volumeManager kubeletvolume.VolumeManager
 
 	// Cloud provider interface.
-	cloud cloudprovider.Interface
+	cloud                   cloudprovider.Interface
+	autoDetectCloudProvider bool
 
 	// Reference to this node.
 	nodeRef *api.ObjectReference
@@ -1115,10 +1118,12 @@ func (kl *Kubelet) initialNodeStatus() (*api.Node, error) {
 		}
 	} else {
 		node.Spec.ExternalID = kl.hostname
-		// If no cloud provider is defined - use the one detected by cadvisor
-		info, err := kl.GetCachedMachineInfo()
-		if err == nil {
-			kl.updateCloudProviderFromMachineInfo(node, info)
+		if kl.autoDetectCloudProvider {
+			// If no cloud provider is defined - use the one detected by cadvisor
+			info, err := kl.GetCachedMachineInfo()
+			if err == nil {
+				kl.updateCloudProviderFromMachineInfo(node, info)
+			}
 		}
 	}
 	if err := kl.setNodeStatus(node); err != nil {