Merge pull request #64954 from k82cn/k8s_61312_2

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions here: https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md.

Added unschedulable and network-unavailable toleration.

Signed-off-by: Da K. Ma <klaus1982.cn@gmail.com>

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
part of #61312
fixes: https://github.com/kubernetes/kubernetes/issues/67606

**Release note**:

```release-note
If `TaintNodesByCondition` is enabled, add `node.kubernetes.io/unschedulable` and
 `node.kubernetes.io/network-unavailable` automatically to DaemonSet pods.
```

pkg/controller/daemon/BUILD

@@ -16,7 +16,6 @@ go_library(
     importpath = "k8s.io/kubernetes/pkg/controller/daemon",
     deps = [
         "//pkg/api/v1/pod:go_default_library",
-        "//pkg/apis/core/v1/helper:go_default_library",
         "//pkg/controller:go_default_library",
         "//pkg/controller/daemon/util:go_default_library",
         "//pkg/features:go_default_library",

pkg/controller/daemon/daemon_controller.go

@@ -51,7 +51,6 @@ import (
 	"k8s.io/client-go/util/integer"
 	"k8s.io/client-go/util/workqueue"
 	podutil "k8s.io/kubernetes/pkg/api/v1/pod"
-	v1helper "k8s.io/kubernetes/pkg/apis/core/v1/helper"
 	"k8s.io/kubernetes/pkg/controller"
 	"k8s.io/kubernetes/pkg/controller/daemon/util"
 	"k8s.io/kubernetes/pkg/features"
@@ -1012,7 +1011,7 @@ func (dsc *DaemonSetsController) syncNodes(ds *apps.DaemonSet, podsToDelete, nod
 	if err != nil {
 		generation = nil
 	}
-	template := util.CreatePodTemplate(ds.Spec.Template, generation, hash)
+	template := util.CreatePodTemplate(ds.Namespace, ds.Spec.Template, generation, hash)
 	// Batch the pod creates. Batch sizes start at SlowStartInitialBatchSize
 	// and double with each successful iteration in a kind of "slow start".
 	// This handles attempts to start large numbers of pods that would
@@ -1039,7 +1038,6 @@ func (dsc *DaemonSetsController) syncNodes(ds *apps.DaemonSet, podsToDelete, nod
 					// should be no conflicting node affinity with the target node.
 					podTemplate.Spec.Affinity = util.ReplaceDaemonSetPodNodeNameNodeAffinity(
 						podTemplate.Spec.Affinity, nodesNeedingDaemonPods[ix])
-					podTemplate.Spec.Tolerations = util.AppendNoScheduleTolerationIfNotExist(podTemplate.Spec.Tolerations)
 
 					err = dsc.podControl.CreatePodsWithControllerRef(ds.Namespace, podTemplate,
 						ds, metav1.NewControllerRef(ds, controllerKind))
@@ -1289,49 +1287,7 @@ func (dsc *DaemonSetsController) syncDaemonSet(key string) error {
 }
 
 func (dsc *DaemonSetsController) simulate(newPod *v1.Pod, node *v1.Node, ds *apps.DaemonSet) ([]algorithm.PredicateFailureReason, *schedulercache.NodeInfo, error) {
-	// DaemonSet pods shouldn't be deleted by NodeController in case of node problems.
+	util.AddOrUpdateDaemonPodTolerations(&newPod.Spec, kubelettypes.IsCriticalPod(newPod))
-	// Add infinite toleration for taint notReady:NoExecute here
-	// to survive taint-based eviction enforced by NodeController
-	// when node turns not ready.
-	v1helper.AddOrUpdateTolerationInPod(newPod, &v1.Toleration{
-		Key:      algorithm.TaintNodeNotReady,
-		Operator: v1.TolerationOpExists,
-		Effect:   v1.TaintEffectNoExecute,
-	})
-
-	// DaemonSet pods shouldn't be deleted by NodeController in case of node problems.
-	// Add infinite toleration for taint unreachable:NoExecute here
-	// to survive taint-based eviction enforced by NodeController
-	// when node turns unreachable.
-	v1helper.AddOrUpdateTolerationInPod(newPod, &v1.Toleration{
-		Key:      algorithm.TaintNodeUnreachable,
-		Operator: v1.TolerationOpExists,
-		Effect:   v1.TaintEffectNoExecute,
-	})
-
-	// According to TaintNodesByCondition, all DaemonSet pods should tolerate
-	// MemoryPressure and DisPressure taints, and the critical pods should tolerate
-	// OutOfDisk taint additional.
-	v1helper.AddOrUpdateTolerationInPod(newPod, &v1.Toleration{
-		Key:      algorithm.TaintNodeDiskPressure,
-		Operator: v1.TolerationOpExists,
-		Effect:   v1.TaintEffectNoSchedule,
-	})
-
-	v1helper.AddOrUpdateTolerationInPod(newPod, &v1.Toleration{
-		Key:      algorithm.TaintNodeMemoryPressure,
-		Operator: v1.TolerationOpExists,
-		Effect:   v1.TaintEffectNoSchedule,
-	})
-
-	// TODO(#48843) OutOfDisk taints will be removed in 1.10
-	if kubelettypes.IsCriticalPod(newPod) {
-		v1helper.AddOrUpdateTolerationInPod(newPod, &v1.Toleration{
-			Key:      algorithm.TaintNodeOutOfDisk,
-			Operator: v1.TolerationOpExists,
-			Effect:   v1.TaintEffectNoSchedule,
-		})
-	}
 
 	objects, err := dsc.podNodeIndex.ByIndex("nodeName", node.Name)
 	if err != nil {

pkg/controller/daemon/daemon_controller_test.go

@@ -437,6 +437,12 @@ func markPodReady(pod *v1.Pod) {
 	podutil.UpdatePodCondition(&pod.Status, &condition)
 }
 
+func setFeatureGate(t *testing.T, feature utilfeature.Feature, enabled bool) {
+	if err := utilfeature.DefaultFeatureGate.Set(fmt.Sprintf("%s=%t", feature, enabled)); err != nil {
+		t.Fatalf("Failed to set FeatureGate %v to %t: %v", feature, enabled, err)
+	}
+}
+
 // DaemonSets without node selectors should launch pods on every node.
 func TestSimpleDaemonSetLaunchesPods(t *testing.T) {
 	for _, strategy := range updateStrategies() {
@@ -460,12 +466,9 @@ func TestSimpleDaemonSetScheduleDaemonSetPodsLaunchesPods(t *testing.T) {
 	enabled := utilfeature.DefaultFeatureGate.Enabled(features.ScheduleDaemonSetPods)
 	// Rollback feature gate.
 	defer func() {
-		if !enabled {
+		setFeatureGate(t, features.ScheduleDaemonSetPods, enabled)
-			utilfeature.DefaultFeatureGate.Set("ScheduleDaemonSetPods=false")
-		}
 	}()
-
+	setFeatureGate(t, features.ScheduleDaemonSetPods, true)
-	utilfeature.DefaultFeatureGate.Set("ScheduleDaemonSetPods=true")
 
 	nodeNum := 5
 
@@ -1576,6 +1579,11 @@ func setDaemonSetToleration(ds *apps.DaemonSet, tolerations []v1.Toleration) {
 // DaemonSet should launch a critical pod even when the node with OutOfDisk taints.
 // TODO(#48843) OutOfDisk taints will be removed in 1.10
 func TestTaintOutOfDiskNodeDaemonLaunchesCriticalPod(t *testing.T) {
+	enabled := utilfeature.DefaultFeatureGate.Enabled(features.ExperimentalCriticalPodAnnotation)
+	defer func() {
+		setFeatureGate(t, features.ExperimentalCriticalPodAnnotation, enabled)
+	}()
+
 	for _, strategy := range updateStrategies() {
 		ds := newDaemonSet("critical")
 		ds.Spec.UpdateStrategy = *strategy
@@ -1593,25 +1601,24 @@ func TestTaintOutOfDiskNodeDaemonLaunchesCriticalPod(t *testing.T) {
 		// NOTE: Whether or not TaintNodesByCondition is enabled, it'll add toleration to DaemonSet pods.
 
 		// Without enabling critical pod annotation feature gate, we shouldn't create critical pod
-		utilfeature.DefaultFeatureGate.Set("ExperimentalCriticalPodAnnotation=False")
+		setFeatureGate(t, features.ExperimentalCriticalPodAnnotation, false)
-		utilfeature.DefaultFeatureGate.Set("TaintNodesByCondition=True")
 		manager.dsStore.Add(ds)
 		syncAndValidateDaemonSets(t, manager, ds, podControl, 0, 0, 0)
 
 		// With enabling critical pod annotation feature gate, we will create critical pod
-		utilfeature.DefaultFeatureGate.Set("ExperimentalCriticalPodAnnotation=True")
+		setFeatureGate(t, features.ExperimentalCriticalPodAnnotation, true)
-		utilfeature.DefaultFeatureGate.Set("TaintNodesByCondition=False")
 		manager.dsStore.Add(ds)
 		syncAndValidateDaemonSets(t, manager, ds, podControl, 1, 0, 0)
-
-		// Rollback feature gate to false.
-		utilfeature.DefaultFeatureGate.Set("TaintNodesByCondition=False")
-		utilfeature.DefaultFeatureGate.Set("ExperimentalCriticalPodAnnotation=False")
 	}
 }
 
 // DaemonSet should launch a pod even when the node with MemoryPressure/DiskPressure taints.
 func TestTaintPressureNodeDaemonLaunchesPod(t *testing.T) {
+	enabled := utilfeature.DefaultFeatureGate.Enabled(features.TaintNodesByCondition)
+	defer func() {
+		setFeatureGate(t, features.TaintNodesByCondition, enabled)
+	}()
+
 	for _, strategy := range updateStrategies() {
 		ds := newDaemonSet("critical")
 		ds.Spec.UpdateStrategy = *strategy
@@ -1633,17 +1640,19 @@ func TestTaintPressureNodeDaemonLaunchesPod(t *testing.T) {
 		manager.nodeStore.Add(node)
 
 		// Enabling critical pod and taint nodes by condition feature gate should create critical pod
-		utilfeature.DefaultFeatureGate.Set("TaintNodesByCondition=True")
+		setFeatureGate(t, features.TaintNodesByCondition, true)
 		manager.dsStore.Add(ds)
 		syncAndValidateDaemonSets(t, manager, ds, podControl, 1, 0, 0)
-
-		// Rollback feature gate to false.
-		utilfeature.DefaultFeatureGate.Set("TaintNodesByCondition=False")
 	}
 }
 
 // DaemonSet should launch a critical pod even when the node has insufficient free resource.
 func TestInsufficientCapacityNodeDaemonLaunchesCriticalPod(t *testing.T) {
+	enabled := utilfeature.DefaultFeatureGate.Enabled(features.ExperimentalCriticalPodAnnotation)
+	defer func() {
+		setFeatureGate(t, features.ExperimentalCriticalPodAnnotation, enabled)
+	}()
+
 	for _, strategy := range updateStrategies() {
 		podSpec := resourcePodSpec("too-much-mem", "75M", "75m")
 		ds := newDaemonSet("critical")
@@ -1663,7 +1672,7 @@ func TestInsufficientCapacityNodeDaemonLaunchesCriticalPod(t *testing.T) {
 		})
 
 		// Without enabling critical pod annotation feature gate, we shouldn't create critical pod
-		utilfeature.DefaultFeatureGate.Set("ExperimentalCriticalPodAnnotation=False")
+		setFeatureGate(t, features.ExperimentalCriticalPodAnnotation, false)
 		manager.dsStore.Add(ds)
 		switch strategy.Type {
 		case apps.OnDeleteDaemonSetStrategyType:
@@ -1675,7 +1684,7 @@ func TestInsufficientCapacityNodeDaemonLaunchesCriticalPod(t *testing.T) {
 		}
 
 		// Enabling critical pod annotation feature gate should create critical pod
-		utilfeature.DefaultFeatureGate.Set("ExperimentalCriticalPodAnnotation=True")
+		setFeatureGate(t, features.ExperimentalCriticalPodAnnotation, true)
 		switch strategy.Type {
 		case apps.OnDeleteDaemonSetStrategyType:
 			syncAndValidateDaemonSets(t, manager, ds, podControl, 1, 0, 2)
@@ -1689,6 +1698,11 @@ func TestInsufficientCapacityNodeDaemonLaunchesCriticalPod(t *testing.T) {
 
 // DaemonSets should NOT launch a critical pod when there are port conflicts.
 func TestPortConflictNodeDaemonDoesNotLaunchCriticalPod(t *testing.T) {
+	enabled := utilfeature.DefaultFeatureGate.Enabled(features.ExperimentalCriticalPodAnnotation)
+	defer func() {
+		setFeatureGate(t, features.ExperimentalCriticalPodAnnotation, enabled)
+	}()
+
 	for _, strategy := range updateStrategies() {
 		podSpec := v1.PodSpec{
 			NodeName: "port-conflict",
@@ -1708,7 +1722,7 @@ func TestPortConflictNodeDaemonDoesNotLaunchCriticalPod(t *testing.T) {
 			Spec: podSpec,
 		})
 
-		utilfeature.DefaultFeatureGate.Set("ExperimentalCriticalPodAnnotation=True")
+		setFeatureGate(t, features.ExperimentalCriticalPodAnnotation, true)
 		ds := newDaemonSet("critical")
 		ds.Spec.UpdateStrategy = *strategy
 		ds.Spec.Template.Spec = podSpec

pkg/controller/daemon/util/BUILD

@@ -19,7 +19,6 @@ go_library(
         "//staging/src/k8s.io/api/apps/v1:go_default_library",
         "//staging/src/k8s.io/api/core/v1:go_default_library",
         "//staging/src/k8s.io/api/extensions/v1beta1:go_default_library",
-        "//staging/src/k8s.io/apimachinery/pkg/api/equality:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/util/feature:go_default_library",
     ],

pkg/controller/daemon/util/daemonset_util.go

@@ -23,7 +23,6 @@ import (
 	apps "k8s.io/api/apps/v1"
 	"k8s.io/api/core/v1"
 	extensions "k8s.io/api/extensions/v1beta1"
-	apiequality "k8s.io/apimachinery/pkg/api/equality"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	podutil "k8s.io/kubernetes/pkg/api/v1/pod"
@@ -49,16 +48,13 @@ func GetTemplateGeneration(ds *apps.DaemonSet) (*int64, error) {
 	return &generation, nil
 }
 
-// CreatePodTemplate returns copy of provided template with additional
+// AddOrUpdateDaemonPodTolerations apply necessary tolerations to DeamonSet Pods, e.g. node.kubernetes.io/not-ready:NoExecute.
-// label which contains templateGeneration (for backward compatibility),
+func AddOrUpdateDaemonPodTolerations(spec *v1.PodSpec, isCritical bool) {
-// hash of provided template and sets default daemon tolerations.
-func CreatePodTemplate(template v1.PodTemplateSpec, generation *int64, hash string) v1.PodTemplateSpec {
-	newTemplate := *template.DeepCopy()
 	// DaemonSet pods shouldn't be deleted by NodeController in case of node problems.
 	// Add infinite toleration for taint notReady:NoExecute here
 	// to survive taint-based eviction enforced by NodeController
 	// when node turns not ready.
-	v1helper.AddOrUpdateTolerationInPodSpec(&newTemplate.Spec, &v1.Toleration{
+	v1helper.AddOrUpdateTolerationInPodSpec(spec, &v1.Toleration{
 		Key:      algorithm.TaintNodeNotReady,
 		Operator: v1.TolerationOpExists,
 		Effect:   v1.TaintEffectNoExecute,
@@ -68,36 +64,67 @@ func CreatePodTemplate(template v1.PodTemplateSpec, generation *int64, hash stri
 	// Add infinite toleration for taint unreachable:NoExecute here
 	// to survive taint-based eviction enforced by NodeController
 	// when node turns unreachable.
-	v1helper.AddOrUpdateTolerationInPodSpec(&newTemplate.Spec, &v1.Toleration{
+	v1helper.AddOrUpdateTolerationInPodSpec(spec, &v1.Toleration{
 		Key:      algorithm.TaintNodeUnreachable,
 		Operator: v1.TolerationOpExists,
 		Effect:   v1.TaintEffectNoExecute,
 	})
 
 	// According to TaintNodesByCondition feature, all DaemonSet pods should tolerate
-	// MemoryPressure and DisPressure taints, and the critical pods should tolerate
+	// MemoryPressure, DisPressure, Unschedulable and NetworkUnavailable taints,
-	// OutOfDisk taint.
+	// and the critical pods should tolerate OutOfDisk taint.
-	v1helper.AddOrUpdateTolerationInPodSpec(&newTemplate.Spec, &v1.Toleration{
+	v1helper.AddOrUpdateTolerationInPodSpec(spec, &v1.Toleration{
 		Key:      algorithm.TaintNodeDiskPressure,
 		Operator: v1.TolerationOpExists,
 		Effect:   v1.TaintEffectNoSchedule,
 	})
 
-	v1helper.AddOrUpdateTolerationInPodSpec(&newTemplate.Spec, &v1.Toleration{
+	v1helper.AddOrUpdateTolerationInPodSpec(spec, &v1.Toleration{
 		Key:      algorithm.TaintNodeMemoryPressure,
 		Operator: v1.TolerationOpExists,
 		Effect:   v1.TaintEffectNoSchedule,
 	})
 
+	v1helper.AddOrUpdateTolerationInPodSpec(spec, &v1.Toleration{
+		Key:      algorithm.TaintNodeUnschedulable,
+		Operator: v1.TolerationOpExists,
+		Effect:   v1.TaintEffectNoSchedule,
+	})
+
+	if spec.HostNetwork {
+		v1helper.AddOrUpdateTolerationInPodSpec(spec, &v1.Toleration{
+			Key:      algorithm.TaintNodeNetworkUnavailable,
+			Operator: v1.TolerationOpExists,
+			Effect:   v1.TaintEffectNoSchedule,
+		})
+	}
+
 	// TODO(#48843) OutOfDisk taints will be removed in 1.10
-	if utilfeature.DefaultFeatureGate.Enabled(features.ExperimentalCriticalPodAnnotation) &&
+	if isCritical {
-		kubelettypes.IsCritical(newTemplate.Namespace, newTemplate.Annotations) {
+		v1helper.AddOrUpdateTolerationInPodSpec(spec, &v1.Toleration{
-		v1helper.AddOrUpdateTolerationInPodSpec(&newTemplate.Spec, &v1.Toleration{
 			Key:      algorithm.TaintNodeOutOfDisk,
 			Operator: v1.TolerationOpExists,
 			Effect:   v1.TaintEffectNoExecute,
 		})
+		v1helper.AddOrUpdateTolerationInPodSpec(spec, &v1.Toleration{
+			Key:      algorithm.TaintNodeOutOfDisk,
+			Operator: v1.TolerationOpExists,
+			Effect:   v1.TaintEffectNoSchedule,
+		})
 	}
+}
+
+// CreatePodTemplate returns copy of provided template with additional
+// label which contains templateGeneration (for backward compatibility),
+// hash of provided template and sets default daemon tolerations.
+func CreatePodTemplate(ns string, template v1.PodTemplateSpec, generation *int64, hash string) v1.PodTemplateSpec {
+	newTemplate := *template.DeepCopy()
+
+	// TODO(k82cn): when removing CritialPod feature, also remove 'ns' parameter.
+	isCritical := utilfeature.DefaultFeatureGate.Enabled(features.ExperimentalCriticalPodAnnotation) &&
+		kubelettypes.IsCritical(ns, newTemplate.Annotations)
+
+	AddOrUpdateDaemonPodTolerations(&newTemplate.Spec, isCritical)
 
 	if newTemplate.ObjectMeta.Labels == nil {
 		newTemplate.ObjectMeta.Labels = make(map[string]string)
@@ -185,31 +212,6 @@ func ReplaceDaemonSetPodNodeNameNodeAffinity(affinity *v1.Affinity, nodename str
 	return affinity
 }
 
-// AppendNoScheduleTolerationIfNotExist appends unschedulable toleration to `.spec` if not exist; otherwise,
-// no changes to `.spec.tolerations`.
-func AppendNoScheduleTolerationIfNotExist(tolerations []v1.Toleration) []v1.Toleration {
-	unschedulableToleration := v1.Toleration{
-		Key:      algorithm.TaintNodeUnschedulable,
-		Operator: v1.TolerationOpExists,
-		Effect:   v1.TaintEffectNoSchedule,
-	}
-
-	unschedulableTaintExist := false
-
-	for _, t := range tolerations {
-		if apiequality.Semantic.DeepEqual(t, unschedulableToleration) {
-			unschedulableTaintExist = true
-			break
-		}
-	}
-
-	if !unschedulableTaintExist {
-		tolerations = append(tolerations, unschedulableToleration)
-	}
-
-	return tolerations
-}
-
 // GetTargetNodeName get the target node name of DaemonSet pods. If `.spec.NodeName` is not empty (nil),
 // return `.spec.NodeName`; otherwise, retrieve node name of pending pods from NodeAffinity. Return error
 // if failed to retrieve node name from `.spec.NodeName` and NodeAffinity.

pkg/controller/daemon/util/daemonset_util_test.go

@@ -154,7 +154,7 @@ func TestCreatePodTemplate(t *testing.T) {
 	}
 	for _, test := range tests {
 		podTemplateSpec := v1.PodTemplateSpec{}
-		newPodTemplate := CreatePodTemplate(podTemplateSpec, test.templateGeneration, test.hash)
+		newPodTemplate := CreatePodTemplate("", podTemplateSpec, test.templateGeneration, test.hash)
 		val, exists := newPodTemplate.ObjectMeta.Labels[extensions.DaemonSetTemplateGenerationKey]
 		if !exists || val != fmt.Sprint(*test.templateGeneration) {
 			t.Errorf("Expected podTemplateSpec to have generation label value: %d, got: %s", *test.templateGeneration, val)

test/integration/daemonset/daemonset_test.go

@@ -94,6 +94,9 @@ func setupScheduler(
 		return
 	}
 
+	// Enable Features.
+	algorithmprovider.ApplyFeatureGates()
+
 	schedulerConfigFactory := factory.NewConfigFactory(&factory.ConfigFactoryArgs{
 		SchedulerName:                  v1.DefaultSchedulerName,
 		Client:                         cs,
@@ -297,7 +300,8 @@ func validateDaemonSetPodsAndMarkReady(
 	podClient corev1typed.PodInterface,
 	podInformer cache.SharedIndexInformer,
 	numberPods int,
-	t *testing.T) {
+	t *testing.T,
+) {
 	if err := wait.Poll(10*time.Second, 60*time.Second, func() (bool, error) {
 		objects := podInformer.GetIndexer().List()
 		if len(objects) != numberPods {
@@ -484,11 +488,15 @@ func forEachFeatureGate(t *testing.T, tf func(t *testing.T)) {
 		func() {
 			enabled := utilfeature.DefaultFeatureGate.Enabled(fg)
 			defer func() {
-				utilfeature.DefaultFeatureGate.Set(fmt.Sprintf("%v=%t", fg, enabled))
+				if err := utilfeature.DefaultFeatureGate.Set(fmt.Sprintf("%v=%t", fg, enabled)); err != nil {
+					t.Fatalf("Failed to set FeatureGate %v to %t", fg, enabled)
+				}
 			}()
 
 			for _, f := range []bool{true, false} {
-				utilfeature.DefaultFeatureGate.Set(fmt.Sprintf("%v=%t", fg, f))
+				if err := utilfeature.DefaultFeatureGate.Set(fmt.Sprintf("%v=%t", fg, f)); err != nil {
+					t.Fatalf("Failed to set FeatureGate %v to %t", fg, f)
+				}
 				t.Run(fmt.Sprintf("%v (%t)", fg, f), tf)
 			}
 		}()
@@ -739,11 +747,15 @@ func TestInsufficientCapacityNodeDaemonDoesNotLaunchPod(t *testing.T) {
 func TestInsufficientCapacityNodeWhenScheduleDaemonSetPodsEnabled(t *testing.T) {
 	enabled := utilfeature.DefaultFeatureGate.Enabled(features.ScheduleDaemonSetPods)
 	defer func() {
-		utilfeature.DefaultFeatureGate.Set(fmt.Sprintf("%s=%t",
+		if err := utilfeature.DefaultFeatureGate.Set(fmt.Sprintf("%s=%t",
-			features.ScheduleDaemonSetPods, enabled))
+			features.ScheduleDaemonSetPods, enabled)); err != nil {
+			t.Fatalf("Failed to set FeatureGate %v to %t", features.ScheduleDaemonSetPods, enabled)
+		}
 	}()
 
-	utilfeature.DefaultFeatureGate.Set(fmt.Sprintf("%s=%t", features.ScheduleDaemonSetPods, true))
+	if err := utilfeature.DefaultFeatureGate.Set(fmt.Sprintf("%s=%t", features.ScheduleDaemonSetPods, true)); err != nil {
+		t.Fatalf("Failed to set FeatureGate %v to %t", features.ScheduleDaemonSetPods, true)
+	}
 
 	forEachStrategy(t, func(t *testing.T, strategy *apps.DaemonSetUpdateStrategy) {
 		server, closeFn, dc, informers, clientset := setup(t)
@@ -980,3 +992,87 @@ func TestTaintedNode(t *testing.T) {
 		})
 	})
 }
+
+// TestUnschedulableNodeDaemonDoesLaunchPod tests that the DaemonSet Pods can still be scheduled
+// to the Unschedulable nodes when TaintNodesByCondition are enabled.
+func TestUnschedulableNodeDaemonDoesLaunchPod(t *testing.T) {
+	enabledTaint := utilfeature.DefaultFeatureGate.Enabled(features.TaintNodesByCondition)
+	defer func() {
+		if err := utilfeature.DefaultFeatureGate.Set(fmt.Sprintf("%s=%t",
+			features.TaintNodesByCondition, enabledTaint)); err != nil {
+			t.Fatalf("Failed to set FeatureGate %v to %t", features.TaintNodesByCondition, enabledTaint)
+		}
+	}()
+	if err := utilfeature.DefaultFeatureGate.Set(fmt.Sprintf("%s=%t", features.TaintNodesByCondition, true)); err != nil {
+		t.Fatalf("Failed to set FeatureGate %v to %t", features.TaintNodesByCondition, true)
+	}
+
+	forEachFeatureGate(t, func(t *testing.T) {
+		forEachStrategy(t, func(t *testing.T, strategy *apps.DaemonSetUpdateStrategy) {
+			server, closeFn, dc, informers, clientset := setup(t)
+			defer closeFn()
+			ns := framework.CreateTestingNamespace("daemonset-unschedulable-test", server, t)
+			defer framework.DeleteTestingNamespace(ns, server, t)
+
+			dsClient := clientset.AppsV1().DaemonSets(ns.Name)
+			podClient := clientset.CoreV1().Pods(ns.Name)
+			nodeClient := clientset.CoreV1().Nodes()
+			podInformer := informers.Core().V1().Pods().Informer()
+
+			stopCh := make(chan struct{})
+			defer close(stopCh)
+
+			informers.Start(stopCh)
+			go dc.Run(5, stopCh)
+
+			// Start Scheduler
+			setupScheduler(t, clientset, informers, stopCh)
+
+			ds := newDaemonSet("foo", ns.Name)
+			ds.Spec.UpdateStrategy = *strategy
+			ds.Spec.Template.Spec.HostNetwork = true
+			_, err := dsClient.Create(ds)
+			if err != nil {
+				t.Fatalf("Failed to create DaemonSet: %v", err)
+			}
+
+			defer cleanupDaemonSets(t, clientset, ds)
+
+			// Creates unschedulable node.
+			node := newNode("unschedulable-node", nil)
+			node.Spec.Unschedulable = true
+			node.Spec.Taints = []v1.Taint{
+				{
+					Key:    algorithm.TaintNodeUnschedulable,
+					Effect: v1.TaintEffectNoSchedule,
+				},
+			}
+
+			_, err = nodeClient.Create(node)
+			if err != nil {
+				t.Fatalf("Failed to create node: %v", err)
+			}
+
+			// Creates network-unavailable node.
+			nodeNU := newNode("network-unavailable-node", nil)
+			nodeNU.Status.Conditions = []v1.NodeCondition{
+				{Type: v1.NodeReady, Status: v1.ConditionFalse},
+				{Type: v1.NodeNetworkUnavailable, Status: v1.ConditionTrue},
+			}
+			nodeNU.Spec.Taints = []v1.Taint{
+				{
+					Key:    algorithm.TaintNodeNetworkUnavailable,
+					Effect: v1.TaintEffectNoSchedule,
+				},
+			}
+
+			_, err = nodeClient.Create(nodeNU)
+			if err != nil {
+				t.Fatalf("Failed to create node: %v", err)
+			}
+
+			validateDaemonSetPodsAndMarkReady(podClient, podInformer, 2, t)
+			validateDaemonSetStatus(dsClient, ds.Name, 2, t)
+		})
+	})
+}