Update pluginwatcher to ignore CSI metadata dir and non socket files

pkg/kubelet/config/defaults.go

@@ -21,6 +21,7 @@ const (
 	DefaultKubeletVolumesDirName             = "volumes"
 	DefaultKubeletVolumeDevicesDirName       = "volumeDevices"
 	DefaultKubeletPluginsDirName             = "plugins"
+	DefaultKubeletPluginsRegistrationDirName = "plugins_registry"
 	DefaultKubeletContainersDirName          = "containers"
 	DefaultKubeletPluginContainersDirName    = "plugin-containers"
 	DefaultKubeletPodResourcesDirName        = "pod-resources"

pkg/kubelet/kubelet.go

@@ -789,7 +789,7 @@ func NewMainKubelet(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
 		return nil, err
 	}
 	if klet.enablePluginsWatcher {
-		klet.pluginWatcher = pluginwatcher.NewWatcher(klet.getPluginsDir())
+		klet.pluginWatcher = pluginwatcher.NewWatcher(klet.getPluginsRegistrationDir())
 	}
 
 	// If the experimentalMounterPathFlag is set, we do not want to
@@ -1260,6 +1260,9 @@ func (kl *Kubelet) setupDataDirs() error {
 	if err := os.MkdirAll(kl.getPluginsDir(), 0750); err != nil {
 		return fmt.Errorf("error creating plugins directory: %v", err)
 	}
+	if err := os.MkdirAll(kl.getPluginsRegistrationDir(), 0750); err != nil {
+		return fmt.Errorf("error creating plugins registry directory: %v", err)
+	}
 	if err := os.MkdirAll(kl.getPodResourcesDir(), 0750); err != nil {
 		return fmt.Errorf("error creating podresources directory: %v", err)
 	}

pkg/kubelet/kubelet_getters.go

@@ -57,6 +57,14 @@ func (kl *Kubelet) getPluginsDir() string {
 	return filepath.Join(kl.getRootDir(), config.DefaultKubeletPluginsDirName)
 }
 
+// getPluginsRegistrationDir returns the full path to the directory under which
+// plugins socket should be placed to be registered.
+// More information is available about plugin registration in the pluginwatcher
+// module
+func (kl *Kubelet) getPluginsRegistrationDir() string {
+	return filepath.Join(kl.getRootDir(), config.DefaultKubeletPluginsRegistrationDirName)
+}
+
 // getPluginDir returns a data directory name for a given plugin name.
 // Plugins can use these directories to store data that they need to persist.
 // For per-pod plugin data, see getPodPluginDir.

pkg/kubelet/util/pluginwatcher/BUILD

@@ -29,6 +29,7 @@ go_test(
     embed = [":go_default_library"],
     deps = [
         "//pkg/kubelet/apis/pluginregistration/v1:go_default_library",
+        "//vendor/github.com/fsnotify/fsnotify:go_default_library",
         "//vendor/github.com/stretchr/testify/require:go_default_library",
         "//vendor/k8s.io/klog:go_default_library",
     ],

pkg/kubelet/util/pluginwatcher/plugin_watcher.go

@@ -211,6 +211,8 @@ func (w *Watcher) traversePluginDir(dir string) error {
 }
 
 // Handle filesystem notify event.
+// Files names:
+// - MUST NOT start with a '.'
 func (w *Watcher) handleCreateEvent(event fsnotify.Event) error {
 	klog.V(6).Infof("Handling create event: %v", event)
 
@@ -220,11 +222,16 @@ func (w *Watcher) handleCreateEvent(event fsnotify.Event) error {
 	}
 
 	if strings.HasPrefix(fi.Name(), ".") {
-		klog.Errorf("Ignoring file: %s", fi.Name())
+		klog.V(5).Infof("Ignoring file (starts with '.'): %s", fi.Name())
 		return nil
 	}
 
 	if !fi.IsDir() {
+		if fi.Mode()&os.ModeSocket == 0 {
+			klog.V(5).Infof("Ignoring non socket file %s", fi.Name())
+			return nil
+		}
+
 		return w.handlePluginRegistration(event.Name)
 	}
 
@@ -290,7 +297,8 @@ func (w *Watcher) handleDeleteEvent(event fsnotify.Event) error {
 
 	plugin, ok := w.getPlugin(event.Name)
 	if !ok {
-		return fmt.Errorf("could not find plugin for deleted file %s", event.Name)
+		klog.V(5).Infof("could not find plugin for deleted file %s", event.Name)
+		return nil
 	}
 
 	// You should not get a Deregister call while registering a plugin