Merge pull request #39014 from resouer/fix-nil-glusterfs

Automatic merge from submit-queue (batch tested with PRs 39029, 39014)

[Glusterfs Vol Plugin]: Check kube client is invalid and return error

Fixes: #38939

In volume plugins, we need to create a kube client to make api call. And this kube client can be nil when, for example, wrong api-server configuration, but kubelet should not crash in this case.

I have also checked other plugins and found only glusterfs need this fix.

pkg/volume/glusterfs/glusterfs.go

@@ -129,7 +129,11 @@ func (plugin *glusterfsPlugin) NewMounter(spec *volume.Spec, pod *v1.Pod, _ volu
 	ep_name := source.EndpointsName
 	// PVC/POD is in same ns.
 	ns := pod.Namespace
-	ep, err := plugin.host.GetKubeClient().Core().Endpoints(ns).Get(ep_name, metav1.GetOptions{})
+	kubeClient := plugin.host.GetKubeClient()
+	if kubeClient == nil {
+		return nil, fmt.Errorf("glusterfs: failed to get kube client to initialize mounter")
+	}
+	ep, err := kubeClient.Core().Endpoints(ns).Get(ep_name, metav1.GetOptions{})
 	if err != nil {
 		glog.Errorf("glusterfs: failed to get endpoints %s[%v]", ep_name, err)
 		return nil, err
@@ -434,7 +438,11 @@ func (d *glusterfsVolumeDeleter) GetPath() string {
 // in a given storage class, and mark them in the table.
 //
 func (p *glusterfsPlugin) collectGids(className string, gidTable *MinMaxAllocator) error {
-	pvList, err := p.host.GetKubeClient().Core().PersistentVolumes().List(v1.ListOptions{LabelSelector: labels.Everything().String()})
+	kubeClient := p.host.GetKubeClient()
+	if kubeClient == nil {
+		return fmt.Errorf("glusterfs: failed to get kube client when collecting gids")
+	}
+	pvList, err := kubeClient.Core().PersistentVolumes().List(v1.ListOptions{LabelSelector: labels.Everything().String()})
 	if err != nil {
 		glog.Errorf("glusterfs: failed to get existing persistent volumes")
 		return err
@@ -761,7 +769,11 @@ func (p *glusterfsVolumeProvisioner) createEndpointService(namespace string, epS
 			Ports:     []v1.EndpointPort{{Port: 1, Protocol: "TCP"}},
 		}},
 	}
-	_, err = p.plugin.host.GetKubeClient().Core().Endpoints(namespace).Create(endpoint)
+	kubeClient := p.plugin.host.GetKubeClient()
+	if kubeClient == nil {
+		return nil, nil, fmt.Errorf("glusterfs: failed to get kube client when creating endpoint service")
+	}
+	_, err = kubeClient.Core().Endpoints(namespace).Create(endpoint)
 	if err != nil && errors.IsAlreadyExists(err) {
 		glog.V(1).Infof("glusterfs: endpoint [%s] already exist in namespace [%s]", endpoint, namespace)
 		err = nil
@@ -781,7 +793,7 @@ func (p *glusterfsVolumeProvisioner) createEndpointService(namespace string, epS
 		Spec: v1.ServiceSpec{
 			Ports: []v1.ServicePort{
 				{Protocol: "TCP", Port: 1}}}}
-	_, err = p.plugin.host.GetKubeClient().Core().Services(namespace).Create(service)
+	_, err = kubeClient.Core().Services(namespace).Create(service)
 	if err != nil && errors.IsAlreadyExists(err) {
 		glog.V(1).Infof("glusterfs: service [%s] already exist in namespace [%s]", service, namespace)
 		err = nil
@@ -794,7 +806,11 @@ func (p *glusterfsVolumeProvisioner) createEndpointService(namespace string, epS
 }
 
 func (d *glusterfsVolumeDeleter) deleteEndpointService(namespace string, epServiceName string) (err error) {
-	err = d.plugin.host.GetKubeClient().Core().Services(namespace).Delete(epServiceName, nil)
+	kubeClient := d.plugin.host.GetKubeClient()
+	if kubeClient == nil {
+		return fmt.Errorf("glusterfs: failed to get kube client when deleting endpoint service")
+	}
+	err = kubeClient.Core().Services(namespace).Delete(epServiceName, nil)
 	if err != nil {
 		glog.Errorf("glusterfs: error deleting service %s/%s: %v", namespace, epServiceName, err)
 		return fmt.Errorf("error deleting service %s/%s: %v", namespace, epServiceName, err)

pkg/volume/util/util.go

@@ -149,6 +149,9 @@ func GetSecretForPV(secretNamespace, secretName, volumePluginName string, kubeCl
 }
 
 func GetClassForVolume(kubeClient clientset.Interface, pv *v1.PersistentVolume) (*storage.StorageClass, error) {
+	if kubeClient == nil {
+		return nil, fmt.Errorf("Cannot get kube client")
+	}
 	// TODO: replace with a real attribute after beta
 	className, found := pv.Annotations["volume.beta.kubernetes.io/storage-class"]
 	if !found {