nfd-worker: Add an option to disable setting the owner references

In some cases it's desirable to control automatic garbage collection
of NodeFeature object.

Add an option to disable setting the owner references to Pod
for NodeFeature object.

Closes: 1817

Signed-off-by: Oleg Zhurakivskyy <oleg.zhurakivskyy@intel.com>

cmd/nfd-worker/main.go

@@ -134,6 +134,8 @@ func initFlags(flagset *flag.FlagSet) (*worker.Args, *worker.ConfigOverrideArgs)
 			" DEPRECATED: will be removed in a future release along with the deprecated gRPC API.")
 	flagset.StringVar(&args.Kubeconfig, "kubeconfig", "",
 		"Kubeconfig to use")
+	flagset.BoolVar(&args.NoOwnerRefs, "no-owner-refs", false,
+		"Do not set owner references for NodeFeature object")
 	flagset.BoolVar(&args.Oneshot, "oneshot", false,
 		"Do not publish feature labels")
 	flagset.IntVar(&args.MetricsPort, "metrics", 8081,

docs/reference/worker-commandline-reference.md

@@ -253,6 +253,23 @@ Example:
 nfd-worker -no-publish
 ```
 
+### -no-owner-refs
+
+The `-no-owner-refs` flag disables setting the owner references to Pod
+for NodeFeature object.
+
+> **NOTE:** This flag takes precedence over the
+> [`core.noOwnerRefs`](worker-configuration-reference.md#corenoownerrefs)
+> configuration file option.
+
+Default: *false*
+
+Example:
+
+```bash
+nfd-worker -no-owner-refs
+```
+
 ### -oneshot
 
 The `-oneshot` flag causes nfd-worker to exit after one pass of feature

docs/reference/worker-configuration-reference.md

@@ -149,6 +149,24 @@ core:
   noPublish: true
 ```
 
+### core.noOwnerRefs
+
+Setting `core.noOwnerRefs` to `true` disables setting the owner references
+to Pod for NodeFeature object.
+
+> **NOTE:** Overridden by the
+> [`-no-owner-refs`](worker-commandline-reference.md#-no-owner-refs)
+> command line flag (if specified).
+
+Default: `false`
+
+Example:
+
+```yaml
+core:
+  noOwnerRefs: true
+```
+
 ### core.klog
 
 The following options specify the logger configuration. Most of which can be

pkg/nfd-worker/nfd-worker.go

@@ -84,6 +84,7 @@ type coreConfig struct {
 	Klog           klogutils.KlogConfigOpts
 	LabelWhiteList utils.RegexpVal
 	NoPublish      bool
+	NoOwnerRefs    bool
 	FeatureSources []string
 	Sources        *[]string
 	LabelSources   []string
@@ -103,6 +104,7 @@ type Args struct {
 	KeyFile            string
 	Klog               map[string]*utils.KlogFlagVal
 	Kubeconfig         string
+	NoOwnerRefs        bool
 	Oneshot            bool
 	Options            string
 	Server             string
@@ -292,6 +294,41 @@ func (w *nfdWorker) runFeatureDiscovery() error {
 	return nil
 }
 
+func (w *nfdWorker) addOwnerReference() error {
+	ownerReference := []metav1.OwnerReference{}
+
+	// Get pod owner reference
+	podName := os.Getenv("POD_NAME")
+
+	// Add pod owner reference if it exists
+	if podName != "" {
+		if selfPod, err := w.k8sClient.CoreV1().Pods(w.kubernetesNamespace).Get(context.TODO(), podName, metav1.GetOptions{}); err != nil {
+			klog.ErrorS(err, "failed to get self pod, cannot inherit ownerReference for NodeFeature")
+			return err
+		} else {
+			ownerReference = append(ownerReference, selfPod.OwnerReferences...)
+		}
+
+		podUID := os.Getenv("POD_UID")
+		if podUID != "" {
+			ownerReference = append(ownerReference, metav1.OwnerReference{
+				APIVersion: "v1",
+				Kind:       "Pod",
+				Name:       podName,
+				UID:        types.UID(podUID),
+			})
+		} else {
+			klog.InfoS("Cannot append POD ownerReference to NodeFeature, POD_UID not specified")
+		}
+	} else {
+		klog.InfoS("Cannot set NodeFeature owner references, POD_NAME not specified")
+	}
+
+	w.ownerReference = ownerReference
+
+	return nil
+}
+
 // Run NfdWorker client. Returns if a fatal error is encountered, or, after
 // one request if OneShot is set to 'true' in the worker args.
 func (w *nfdWorker) Run() error {
@@ -319,37 +356,13 @@ func (w *nfdWorker) Run() error {
 	labelTrigger.Reset(w.config.Core.SleepInterval.Duration)
 	defer labelTrigger.Stop()
 
-	// Create owner ref
-	ownerReference := []metav1.OwnerReference{}
-	// Get pod owner reference
-	podName := os.Getenv("POD_NAME")
-
-	// Add pod owner reference if it exists
-	if podName != "" {
-		if selfPod, err := w.k8sClient.CoreV1().Pods(w.kubernetesNamespace).Get(context.TODO(), podName, metav1.GetOptions{}); err != nil {
-			klog.ErrorS(err, "failed to get self pod, cannot inherit ownerReference for NodeFeature")
+	if !w.config.Core.NoOwnerRefs {
+		err := w.addOwnerReference()
+		if err != nil {
 			return err
-		} else {
-			ownerReference = append(ownerReference, selfPod.OwnerReferences...)
-		}
-
-		podUID := os.Getenv("POD_UID")
-		if podUID != "" {
-			ownerReference = append(ownerReference, metav1.OwnerReference{
-				APIVersion: "v1",
-				Kind:       "Pod",
-				Name:       podName,
-				UID:        types.UID(podUID),
-			})
-		} else {
-			klog.InfoS("Cannot append POD ownerReference to NodeFeature, POD_UID not specified")
 		}
-	} else {
-		klog.InfoS("Cannot set NodeFeature owner references, POD_NAME not specified")
 	}
 
-	w.ownerReference = ownerReference
-
 	// Register to metrics server
 	if w.args.MetricsPort > 0 {
 		m := utils.CreateMetricsServer(w.args.MetricsPort,