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

@@ -94,6 +94,8 @@ func parseArgs(flags *flag.FlagSet, osArgs ...string) *worker.Args {
 			args.Overrides.FeatureSources = overrides.FeatureSources
 		case "label-sources":
 			args.Overrides.LabelSources = overrides.LabelSources
+		case "no-owner-refs":
+			args.Overrides.NoOwnerRefs = overrides.NoOwnerRefs
 		}
 	})
 
@@ -126,6 +128,8 @@ func initFlags(flagset *flag.FlagSet) (*worker.Args, *worker.ConfigOverrideArgs)
 	}
 	overrides.NoPublish = flagset.Bool("no-publish", false,
 		"Do not publish discovered features, disable connection to nfd-master and don't create NodeFeature object.")
+	overrides.NoOwnerRefs = flagset.Bool("no-owner-refs", false,
+		"Do not set owner references for NodeFeature object.")
 	flagset.Var(overrides.FeatureSources, "feature-sources",
 		"Comma separated list of feature sources. Special value 'all' enables all sources. "+
 			"Prefix the source name with '-' to disable it.")

cmd/nfd-worker/main_test.go

@@ -43,12 +43,14 @@ func TestParseArgs(t *testing.T) {
 		Convey("When all override args are specified", func() {
 			args := parseArgs(flags,
 				"-no-publish",
+				"-no-owner-refs",
 				"-feature-sources=cpu",
 				"-label-sources=fake1,fake2,fake3")
 
 			Convey("args.sources is set to appropriate values", func() {
 				So(args.Oneshot, ShouldBeFalse)
 				So(*args.Overrides.NoPublish, ShouldBeTrue)
+				So(*args.Overrides.NoOwnerRefs, ShouldBeTrue)
 				So(*args.Overrides.FeatureSources, ShouldResemble, utils.StringSliceVal{"cpu"})
 				So(*args.Overrides.LabelSources, ShouldResemble, utils.StringSliceVal{"fake1", "fake2", "fake3"})
 			})

docs/reference/worker-commandline-reference.md

@@ -162,6 +162,23 @@ Example:
 nfd-worker -no-publish
 ```
 
+### -no-owner-refs
+
+The `-no-owner-refs` flag disables setting the owner references to Pod
+of the 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
+of the NodeFeature object created by the nfd-worker.
+
+> **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.

pkg/nfd-worker/nfd-worker.go

@@ -78,6 +78,7 @@ type coreConfig struct {
 	Klog           klogutils.KlogConfigOpts
 	LabelWhiteList utils.RegexpVal
 	NoPublish      bool
+	NoOwnerRefs    bool
 	FeatureSources []string
 	Sources        *[]string
 	LabelSources   []string
@@ -98,14 +99,15 @@ type Args struct {
 	Options        string
 	MetricsPort    int
 	GrpcHealthPort int
+	NoOwnerRefs    bool
 
 	Overrides ConfigOverrideArgs
 }
 
 // ConfigOverrideArgs are args that override config file options
 type ConfigOverrideArgs struct {
-	NoPublish *bool
-
+	NoPublish      *bool
+	NoOwnerRefs    *bool
 	FeatureSources *utils.StringSliceVal
 	LabelSources   *utils.StringSliceVal
 }
@@ -265,7 +267,44 @@ func (w *nfdWorker) runFeatureDiscovery() error {
 	return nil
 }
 
-// Run NfdWorker client. Returns if a fatal error is encountered, or, after
+// Set owner ref
+func (w *nfdWorker) setOwnerReference() error {
+	ownerReference := []metav1.OwnerReference{}
+
+	if !w.config.Core.NoOwnerRefs {
+		// 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 an error 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 {
 	klog.InfoS("Node Feature Discovery Worker", "version", version.Get(), "nodeName", utils.NodeName(), "namespace", w.kubernetesNamespace)
@@ -281,37 +320,6 @@ 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")
-			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,
@@ -466,6 +474,11 @@ func (w *nfdWorker) configureCore(c coreConfig) error {
 		klogV.InfoS("enabled label sources", "labelSources", n)
 	}
 
+	err = w.setOwnerReference()
+	if err != nil {
+		return err
+	}
+
 	return nil
 }
 
@@ -511,6 +524,9 @@ func (w *nfdWorker) configure(filepath string, overrides string) error {
 	if w.args.Overrides.NoPublish != nil {
 		c.Core.NoPublish = *w.args.Overrides.NoPublish
 	}
+	if w.args.Overrides.NoOwnerRefs != nil {
+		c.Core.NoOwnerRefs = *w.args.Overrides.NoOwnerRefs
+	}
 	if w.args.Overrides.FeatureSources != nil {
 		c.Core.FeatureSources = *w.args.Overrides.FeatureSources
 	}