register Node/UpdateNodeTaint event to plugins which has Node/Add only, doesn't have Node/UpdateNodeTaint

pkg/scheduler/framework/plugins/dynamicresources/dynamicresources.go

@@ -396,7 +396,16 @@ func (pl *dynamicResources) EventsToRegister() []framework.ClusterEventWithHint
 		{Event: framework.ClusterEvent{Resource: framework.PodSchedulingContext, ActionType: framework.Add | framework.Update}, QueueingHintFn: pl.isSchedulableAfterPodSchedulingContextChange},
 		// A resource might depend on node labels for topology filtering.
 		// A new or updated node may make pods schedulable.
-		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.UpdateNodeLabel}},
+		//
+		// A note about UpdateNodeTaint event:
+		// NodeAdd QueueingHint isn't always called because of the internal feature called preCheck.
+		// As a common problematic scenario,
+		// when a node is added but not ready, NodeAdd event is filtered out by preCheck and doesn't arrive.
+		// In such cases, this plugin may miss some events that actually make pods schedulable.
+		// As a workaround, we add UpdateNodeTaint event to catch the case.
+		// We can remove UpdateNodeTaint when we remove the preCheck feature.
+		// See: https://github.com/kubernetes/kubernetes/issues/110175
+		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.UpdateNodeLabel | framework.UpdateNodeTaint}},
 		// A pod might be waiting for a class to get created or modified.
 		{Event: framework.ClusterEvent{Resource: framework.ResourceClass, ActionType: framework.Add | framework.Update}},
 	}

pkg/scheduler/framework/plugins/interpodaffinity/plugin.go

@@ -64,8 +64,17 @@ func (pl *InterPodAffinity) EventsToRegister() []framework.ClusterEventWithHint
 		// an unschedulable Pod schedulable.
 		// - Add. An unschedulable Pod may fail due to violating pod-affinity constraints,
 		// adding an assigned Pod may make it schedulable.
+		//
+		// A note about UpdateNodeTaint event:
+		// NodeAdd QueueingHint isn't always called because of the internal feature called preCheck.
+		// As a common problematic scenario,
+		// when a node is added but not ready, NodeAdd event is filtered out by preCheck and doesn't arrive.
+		// In such cases, this plugin may miss some events that actually make pods schedulable.
+		// As a workaround, we add UpdateNodeTaint event to catch the case.
+		// We can remove UpdateNodeTaint when we remove the preCheck feature.
+		// See: https://github.com/kubernetes/kubernetes/issues/110175
 		{Event: framework.ClusterEvent{Resource: framework.Pod, ActionType: framework.All}},
-		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.UpdateNodeLabel}},
+		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.UpdateNodeLabel | framework.UpdateNodeTaint}},
 	}
 }
 

pkg/scheduler/framework/plugins/podtopologyspread/plugin.go

@@ -146,7 +146,16 @@ func (pl *PodTopologySpread) EventsToRegister() []framework.ClusterEventWithHint
 		{Event: framework.ClusterEvent{Resource: framework.Pod, ActionType: framework.All}, QueueingHintFn: pl.isSchedulableAfterPodChange},
 		// Node add|delete|update maybe lead an topology key changed,
 		// and make these pod in scheduling schedulable or unschedulable.
-		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.Delete | framework.Update}, QueueingHintFn: pl.isSchedulableAfterNodeChange},
+		//
+		// A note about UpdateNodeTaint event:
+		// NodeAdd QueueingHint isn't always called because of the internal feature called preCheck.
+		// As a common problematic scenario,
+		// when a node is added but not ready, NodeAdd event is filtered out by preCheck and doesn't arrive.
+		// In such cases, this plugin may miss some events that actually make pods schedulable.
+		// As a workaround, we add UpdateNodeTaint event to catch the case.
+		// We can remove UpdateNodeTaint when we remove the preCheck feature.
+		// See: https://github.com/kubernetes/kubernetes/issues/110175
+		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.Delete | framework.UpdateNodeLabel | framework.UpdateNodeTaint}, QueueingHintFn: pl.isSchedulableAfterNodeChange},
 	}
 }
 

pkg/scheduler/framework/plugins/volumebinding/volume_binding.go

@@ -103,7 +103,16 @@ func (pl *VolumeBinding) EventsToRegister() []framework.ClusterEventWithHint {
 		// Pods may fail to find available PVs because the node labels do not
 		// match the storage class's allowed topologies or PV's node affinity.
 		// A new or updated node may make pods schedulable.
-		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.UpdateNodeLabel}},
+		//
+		// A note about UpdateNodeTaint event:
+		// NodeAdd QueueingHint isn't always called because of the internal feature called preCheck.
+		// As a common problematic scenario,
+		// when a node is added but not ready, NodeAdd event is filtered out by preCheck and doesn't arrive.
+		// In such cases, this plugin may miss some events that actually make pods schedulable.
+		// As a workaround, we add UpdateNodeTaint event to catch the case.
+		// We can remove UpdateNodeTaint when we remove the preCheck feature.
+		// See: https://github.com/kubernetes/kubernetes/issues/110175
+		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.UpdateNodeLabel | framework.UpdateNodeTaint}},
 		// We rely on CSI node to translate in-tree PV to CSI.
 		{Event: framework.ClusterEvent{Resource: framework.CSINode, ActionType: framework.Add | framework.Update}},
 		// When CSIStorageCapacity is enabled, pods may become schedulable

pkg/scheduler/framework/plugins/volumezone/volume_zone.go

@@ -280,7 +280,16 @@ func (pl *VolumeZone) EventsToRegister() []framework.ClusterEventWithHint {
 		// Due to immutable field `storageClass.volumeBindingMode`, storageClass update events are ignored.
 		{Event: framework.ClusterEvent{Resource: framework.StorageClass, ActionType: framework.Add}},
 		// A new node or updating a node's volume zone labels may make a pod schedulable.
-		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.UpdateNodeLabel}},
+		//
+		// A note about UpdateNodeTaint event:
+		// NodeAdd QueueingHint isn't always called because of the internal feature called preCheck.
+		// As a common problematic scenario,
+		// when a node is added but not ready, NodeAdd event is filtered out by preCheck and doesn't arrive.
+		// In such cases, this plugin may miss some events that actually make pods schedulable.
+		// As a workaround, we add UpdateNodeTaint event to catch the case.
+		// We can remove UpdateNodeTaint when we remove the preCheck feature.
+		// See: https://github.com/kubernetes/kubernetes/issues/110175
+		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.UpdateNodeLabel | framework.UpdateNodeTaint}},
 		// A new pvc may make a pod schedulable.
 		// Due to fields are immutable except `spec.resources`, pvc update events are ignored.
 		{Event: framework.ClusterEvent{Resource: framework.PersistentVolumeClaim, ActionType: framework.Add}},

pkg/scheduler/framework/types.go

@@ -72,7 +72,16 @@ const (
 	//           - a Pod that is deleted
 	//           - a Pod that was assumed, but gets un-assumed due to some errors in the binding cycle.
 	//           - an existing Pod that was unscheduled but gets scheduled to a Node.
-	Pod                     GVK = "Pod"
+	Pod GVK = "Pod"
+	// A note about NodeAdd event and UpdateNodeTaint event:
+	// NodeAdd QueueingHint isn't always called because of the internal feature called preCheck.
+	// It's definitely not something expected for plugin developers,
+	// and registering UpdateNodeTaint event is the only mitigation for now.
+	// So, kube-scheduler registers UpdateNodeTaint event for plugins that has NodeAdded event, but don't have UpdateNodeTaint event.
+	// It has a bad impact for the requeuing efficiency though, a lot better than some Pods being stuck in the
+	// unschedulable pod pool.
+	// This behavior will be removed when we remove the preCheck feature.
+	// See: https://github.com/kubernetes/kubernetes/issues/110175
 	Node                    GVK = "Node"
 	PersistentVolume        GVK = "PersistentVolume"
 	PersistentVolumeClaim   GVK = "PersistentVolumeClaim"

pkg/scheduler/internal/queue/scheduling_queue.go

@@ -118,6 +118,7 @@ type SchedulingQueue interface {
 	AssignedPodAdded(logger klog.Logger, pod *v1.Pod)
 	AssignedPodUpdated(logger klog.Logger, oldPod, newPod *v1.Pod)
 	PendingPods() ([]*v1.Pod, string)
+	PodsInActiveQ() []*v1.Pod
 	// Close closes the SchedulingQueue so that the goroutine which is
 	// waiting to pop items can exit gracefully.
 	Close()
@@ -1227,6 +1228,18 @@ func (p *PriorityQueue) getUnschedulablePodsWithMatchingAffinityTerm(logger klog
 	return podsToMove
 }
 
+// PodsInActiveQ returns all the Pods in the activeQ.
+// This function is only used in tests.
+func (p *PriorityQueue) PodsInActiveQ() []*v1.Pod {
+	p.lock.RLock()
+	defer p.lock.RUnlock()
+	var result []*v1.Pod
+	for _, pInfo := range p.activeQ.List() {
+		result = append(result, pInfo.(*framework.QueuedPodInfo).Pod)
+	}
+	return result
+}
+
 var pendingPodsSummary = "activeQ:%v; backoffQ:%v; unschedulablePods:%v"
 
 // PendingPods returns all the pending pods in the queue; accompanied by a debugging string

pkg/scheduler/schedule_one.go

@@ -62,8 +62,8 @@ const (
 	numberOfHighestScoredNodesToReport = 3
 )
 
-// scheduleOne does the entire scheduling workflow for a single pod. It is serialized on the scheduling algorithm's host fitting.
-func (sched *Scheduler) scheduleOne(ctx context.Context) {
+// ScheduleOne does the entire scheduling workflow for a single pod. It is serialized on the scheduling algorithm's host fitting.
+func (sched *Scheduler) ScheduleOne(ctx context.Context) {
 	logger := klog.FromContext(ctx)
 	podInfo, err := sched.NextPod(logger)
 	if err != nil {

pkg/scheduler/schedule_one_test.go

@@ -811,7 +811,7 @@ func TestSchedulerScheduleOne(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			sched.scheduleOne(ctx)
+			sched.ScheduleOne(ctx)
 			<-called
 			if e, a := item.expectAssumedPod, gotAssumedPod; !reflect.DeepEqual(e, a) {
 				t.Errorf("assumed pod: wanted %v, got %v", e, a)
@@ -884,7 +884,7 @@ func TestSchedulerNoPhantomPodAfterExpire(t *testing.T) {
 	// We use conflicted pod ports to incur fit predicate failure if first pod not removed.
 	secondPod := podWithPort("bar", "", 8080)
 	queuedPodStore.Add(secondPod)
-	scheduler.scheduleOne(ctx)
+	scheduler.ScheduleOne(ctx)
 	select {
 	case b := <-bindingChan:
 		expectBinding := &v1.Binding{
@@ -921,7 +921,7 @@ func TestSchedulerNoPhantomPodAfterDelete(t *testing.T) {
 	// queuedPodStore: [bar:8080]
 	// cache: [(assumed)foo:8080]
 
-	scheduler.scheduleOne(ctx)
+	scheduler.ScheduleOne(ctx)
 	select {
 	case err := <-errChan:
 		expectErr := &framework.FitError{
@@ -954,7 +954,7 @@ func TestSchedulerNoPhantomPodAfterDelete(t *testing.T) {
 	}
 
 	queuedPodStore.Add(secondPod)
-	scheduler.scheduleOne(ctx)
+	scheduler.ScheduleOne(ctx)
 	select {
 	case b := <-bindingChan:
 		expectBinding := &v1.Binding{
@@ -1030,7 +1030,7 @@ func TestSchedulerFailedSchedulingReasons(t *testing.T) {
 	scheduler, _, errChan := setupTestScheduler(ctx, t, queuedPodStore, scache, informerFactory, nil, fns...)
 
 	queuedPodStore.Add(podWithTooBigResourceRequests)
-	scheduler.scheduleOne(ctx)
+	scheduler.ScheduleOne(ctx)
 	select {
 	case err := <-errChan:
 		expectErr := &framework.FitError{
@@ -1160,7 +1160,7 @@ func TestSchedulerWithVolumeBinding(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			s.scheduleOne(ctx)
+			s.ScheduleOne(ctx)
 			// Wait for pod to succeed or fail scheduling
 			select {
 			case <-eventChan:
@@ -3481,7 +3481,7 @@ func setupTestSchedulerWithOnePodOnNode(ctx context.Context, t *testing.T, queue
 	// queuedPodStore: [foo:8080]
 	// cache: []
 
-	scheduler.scheduleOne(ctx)
+	scheduler.ScheduleOne(ctx)
 	// queuedPodStore: []
 	// cache: [(assumed)foo:8080]
 

pkg/scheduler/scheduler.go

@@ -389,17 +389,47 @@ func buildQueueingHintMap(es []framework.EnqueueExtensions) internalqueue.Queuei
 		// cannot be moved by any regular cluster event.
 		// So, we can just ignore such EventsToRegister here.
 
+		registerNodeAdded := false
+		registerNodeTaintUpdated := false
 		for _, event := range events {
 			fn := event.QueueingHintFn
 			if fn == nil || !utilfeature.DefaultFeatureGate.Enabled(features.SchedulerQueueingHints) {
 				fn = defaultQueueingHintFn
 			}
 
+			if event.Event.Resource == framework.Node {
+				if event.Event.ActionType&framework.Add != 0 {
+					registerNodeAdded = true
+				}
+				if event.Event.ActionType&framework.UpdateNodeTaint != 0 {
+					registerNodeTaintUpdated = true
+				}
+			}
+
 			queueingHintMap[event.Event] = append(queueingHintMap[event.Event], &internalqueue.QueueingHintFunction{
 				PluginName:     e.Name(),
 				QueueingHintFn: fn,
 			})
 		}
+		if registerNodeAdded && !registerNodeTaintUpdated {
+			// Temporally fix for the issue https://github.com/kubernetes/kubernetes/issues/109437
+			// NodeAdded QueueingHint isn't always called because of preCheck.
+			// It's definitely not something expected for plugin developers,
+			// and registering UpdateNodeTaint event is the only mitigation for now.
+			//
+			// So, here registers UpdateNodeTaint event for plugins that has NodeAdded event, but don't have UpdateNodeTaint event.
+			// It has a bad impact for the requeuing efficiency though, a lot better than some Pods being stuch in the
+			// unschedulable pod pool.
+			// This behavior will be removed when we remove the preCheck feature.
+			// See: https://github.com/kubernetes/kubernetes/issues/110175
+			queueingHintMap[framework.ClusterEvent{Resource: framework.Node, ActionType: framework.UpdateNodeTaint}] =
+				append(queueingHintMap[framework.ClusterEvent{Resource: framework.Node, ActionType: framework.UpdateNodeTaint}],
+					&internalqueue.QueueingHintFunction{
+						PluginName:     e.Name(),
+						QueueingHintFn: defaultQueueingHintFn,
+					},
+				)
+		}
 	}
 	return queueingHintMap
 }
@@ -415,7 +445,7 @@ func (sched *Scheduler) Run(ctx context.Context) {
 	// If there are no new pods to schedule, it will be hanging there
 	// and if done in this goroutine it will be blocking closing
 	// SchedulingQueue, in effect causing a deadlock on shutdown.
-	go wait.UntilWithContext(ctx, sched.scheduleOne, 0)
+	go wait.UntilWithContext(ctx, sched.ScheduleOne, 0)
 
 	<-ctx.Done()
 	sched.SchedulingQueue.Close()

pkg/scheduler/scheduler_test.go

@@ -662,6 +662,9 @@ func Test_buildQueueingHintMap(t *testing.T) {
 				{Resource: framework.Node, ActionType: framework.Add}: {
 					{PluginName: fakeNode, QueueingHintFn: fakeNodePluginQueueingFn},
 				},
+				{Resource: framework.Node, ActionType: framework.UpdateNodeTaint}: {
+					{PluginName: fakeNode, QueueingHintFn: defaultQueueingHintFn}, // When Node/Add is registered, Node/UpdateNodeTaint is automatically registered.
+				},
 			},
 		},
 		{
@@ -675,6 +678,9 @@ func Test_buildQueueingHintMap(t *testing.T) {
 				{Resource: framework.Node, ActionType: framework.Add}: {
 					{PluginName: fakeNode, QueueingHintFn: defaultQueueingHintFn}, // default queueing hint due to disabled feature gate.
 				},
+				{Resource: framework.Node, ActionType: framework.UpdateNodeTaint}: {
+					{PluginName: fakeNode, QueueingHintFn: defaultQueueingHintFn}, // When Node/Add is registered, Node/UpdateNodeTaint is automatically registered.
+				},
 			},
 		},
 		{
@@ -692,6 +698,9 @@ func Test_buildQueueingHintMap(t *testing.T) {
 				{Resource: framework.Node, ActionType: framework.Add}: {
 					{PluginName: fakeNode, QueueingHintFn: fakeNodePluginQueueingFn},
 				},
+				{Resource: framework.Node, ActionType: framework.UpdateNodeTaint}: {
+					{PluginName: fakeNode, QueueingHintFn: defaultQueueingHintFn}, // When Node/Add is registered, Node/UpdateNodeTaint is automatically registered.
+				},
 			},
 		},
 	}
@@ -800,7 +809,7 @@ func Test_UnionedGVKs(t *testing.T) {
 				Disabled: []schedulerapi.Plugin{{Name: "*"}}, // disable default plugins
 			},
 			want: map[framework.GVK]framework.ActionType{
-				framework.Node: framework.Add,
+				framework.Node: framework.Add | framework.UpdateNodeTaint, // When Node/Add is registered, Node/UpdateNodeTaint is automatically registered.
 			},
 		},
 		{
@@ -830,7 +839,7 @@ func Test_UnionedGVKs(t *testing.T) {
 			},
 			want: map[framework.GVK]framework.ActionType{
 				framework.Pod:  framework.Add,
-				framework.Node: framework.Add,
+				framework.Node: framework.Add | framework.UpdateNodeTaint, // When Node/Add is registered, Node/UpdateNodeTaint is automatically registered.
 			},
 		},
 		{

test/integration/scheduler/queue_test.go

@@ -31,6 +31,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/apimachinery/pkg/util/uuid"
 	"k8s.io/apimachinery/pkg/util/wait"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
@@ -154,89 +155,155 @@ func TestSchedulingGates(t *testing.T) {
 // TestCoreResourceEnqueue verify Pods failed by in-tree default plugins can be
 // moved properly upon their registered events.
 func TestCoreResourceEnqueue(t *testing.T) {
-	// Use zero backoff seconds to bypass backoffQ.
-	// It's intended to not start the scheduler's queue, and hence to
-	// not start any flushing logic. We will pop and schedule the Pods manually later.
-	testCtx := testutils.InitTestSchedulerWithOptions(
-		t,
-		testutils.InitTestAPIServer(t, "core-res-enqueue", nil),
-		0,
-		scheduler.WithPodInitialBackoffSeconds(0),
-		scheduler.WithPodMaxBackoffSeconds(0),
-	)
-	testutils.SyncSchedulerInformerFactory(testCtx)
+	tests := []struct {
+		name string
+		// initialNode is the Node to be created at first.
+		initialNode *v1.Node
+		// initialPod is the Pod to be created at first if it's not empty.
+		initialPod *v1.Pod
+		// pods are the list of Pods to be created.
+		// All of them are expected to be unschedulable at first.
+		pods []*v1.Pod
+		// triggerFn is the function that triggers the event to move Pods.
+		triggerFn func(testCtx *testutils.TestContext) error
+		// wantRequeuedPods is the map of Pods that are expected to be requeued after triggerFn.
+		wantRequeuedPods sets.Set[string]
+	}{
+		{
+			name:        "Pod without a required toleration to a node isn't requeued to activeQ",
+			initialNode: st.MakeNode().Name("fake-node").Capacity(map[v1.ResourceName]string{v1.ResourceCPU: "2"}).Taints([]v1.Taint{{Key: v1.TaintNodeNotReady, Effect: v1.TaintEffectNoSchedule}}).Obj(),
+			pods: []*v1.Pod{
+				// - Pod1 doesn't have the required toleration and will be rejected by the TaintToleration plugin.
+				//   (TaintToleration plugin is evaluated before NodeResourcesFit plugin.)
+				// - Pod2 has the required toleration, but requests a large amount of CPU - will be rejected by the NodeResourcesFit plugin.
+				st.MakePod().Name("pod1").Req(map[v1.ResourceName]string{v1.ResourceCPU: "4"}).Container("image").Obj(),
+				st.MakePod().Name("pod2").Toleration(v1.TaintNodeNotReady).Req(map[v1.ResourceName]string{v1.ResourceCPU: "4"}).Container("image").Obj(),
+			},
+			triggerFn: func(testCtx *testutils.TestContext) error {
+				// Trigger a NodeChange event by increasing CPU capacity.
+				// It makes Pod2 schedulable.
+				// Pod1 is not requeued because the Node is still unready and it doesn't have the required toleration.
+				if _, err := testCtx.ClientSet.CoreV1().Nodes().UpdateStatus(testCtx.Ctx, st.MakeNode().Name("fake-node").Capacity(map[v1.ResourceName]string{v1.ResourceCPU: "4"}).Taints([]v1.Taint{{Key: v1.TaintNodeNotReady, Effect: v1.TaintEffectNoSchedule}}).Obj(), metav1.UpdateOptions{}); err != nil {
+					return fmt.Errorf("failed to update the node: %w", err)
+				}
+				return nil
+			},
+			wantRequeuedPods: sets.New("pod2"),
+		},
+		{
+			name:        "Pod rejected by the PodAffinity plugin is requeued when a new Node is created and turned to ready",
+			initialNode: st.MakeNode().Name("fake-node").Label("node", "fake-node").Capacity(map[v1.ResourceName]string{v1.ResourceCPU: "2"}).Obj(),
+			initialPod:  st.MakePod().Label("anti", "anti").Name("pod1").PodAntiAffinityExists("anti", "node", st.PodAntiAffinityWithRequiredReq).Container("image").Node("fake-node").Obj(),
+			pods: []*v1.Pod{
+				// - Pod2 will be rejected by the PodAffinity plugin.
+				st.MakePod().Label("anti", "anti").Name("pod2").PodAntiAffinityExists("anti", "node", st.PodAntiAffinityWithRequiredReq).Container("image").Obj(),
+			},
+			triggerFn: func(testCtx *testutils.TestContext) error {
+				// Trigger a NodeCreated event.
+				// Note that this Node has a un-ready taint and pod2 should be requeued ideally because unschedulable plugins registered for pod2 is PodAffinity.
+				// However, due to preCheck, it's not requeueing pod2 to activeQ.
+				// It'll be fixed by the removal of preCheck in the future.
+				// https://github.com/kubernetes/kubernetes/issues/110175
+				node := st.MakeNode().Name("fake-node2").Capacity(map[v1.ResourceName]string{v1.ResourceCPU: "2"}).Taints([]v1.Taint{{Key: v1.TaintNodeNotReady, Effect: v1.TaintEffectNoSchedule}}).Obj()
+				if _, err := testCtx.ClientSet.CoreV1().Nodes().Create(testCtx.Ctx, st.MakeNode().Name("fake-node2").Capacity(map[v1.ResourceName]string{v1.ResourceCPU: "2"}).Taints([]v1.Taint{{Key: "foo", Effect: v1.TaintEffectNoSchedule}}).Obj(), metav1.CreateOptions{}); err != nil {
+					return fmt.Errorf("failed to create a newnode: %w", err)
+				}
 
-	defer testCtx.Scheduler.SchedulingQueue.Close()
-
-	cs, ns, ctx := testCtx.ClientSet, testCtx.NS.Name, testCtx.Ctx
-	// Create one Node with a taint.
-	node := st.MakeNode().Name("fake-node").Capacity(map[v1.ResourceName]string{v1.ResourceCPU: "2"}).Obj()
-	node.Spec.Taints = []v1.Taint{{Key: "foo", Effect: v1.TaintEffectNoSchedule}}
-	if _, err := cs.CoreV1().Nodes().Create(ctx, node, metav1.CreateOptions{}); err != nil {
-		t.Fatalf("Failed to create Node %q: %v", node.Name, err)
+				// As a mitigation of an issue described above, all plugins subscribing Node/Add event register UpdateNodeTaint too.
+				// So, this removal of taint moves pod2 to activeQ.
+				node.Spec.Taints = nil
+				if _, err := testCtx.ClientSet.CoreV1().Nodes().Update(testCtx.Ctx, node, metav1.UpdateOptions{}); err != nil {
+					return fmt.Errorf("failed to remove taints off the node: %w", err)
+				}
+				return nil
+			},
+			wantRequeuedPods: sets.New("pod2"),
+		},
 	}
 
-	// Create two Pods that are both unschedulable.
-	// - Pod1 is a best-effort Pod, but doesn't have the required toleration.
-	// - Pod2 requests a large amount of CPU resource that the node cannot fit.
-	//   Note: Pod2 will fail the tainttoleration plugin b/c that's ordered prior to noderesources.
-	// - Pod3 has the required toleration, but requests a non-existing PVC.
-	pod1 := st.MakePod().Namespace(ns).Name("pod1").Container("image").Obj()
-	pod2 := st.MakePod().Namespace(ns).Name("pod2").Req(map[v1.ResourceName]string{v1.ResourceCPU: "4"}).Obj()
-	pod3 := st.MakePod().Namespace(ns).Name("pod3").Toleration("foo").PVC("pvc").Container("image").Obj()
-	for _, pod := range []*v1.Pod{pod1, pod2, pod3} {
-		if _, err := cs.CoreV1().Pods(ns).Create(ctx, pod, metav1.CreateOptions{}); err != nil {
-			t.Fatalf("Failed to create Pod %q: %v", pod.Name, err)
+	for _, featureEnabled := range []bool{false, true} {
+		for _, tt := range tests {
+			t.Run(fmt.Sprintf("%s [SchedulerQueueingHints enabled: %v]", tt.name, featureEnabled), func(t *testing.T) {
+				defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.SchedulerQueueingHints, featureEnabled)()
+
+				// Use zero backoff seconds to bypass backoffQ.
+				// It's intended to not start the scheduler's queue, and hence to
+				// not start any flushing logic. We will pop and schedule the Pods manually later.
+				testCtx := testutils.InitTestSchedulerWithOptions(
+					t,
+					testutils.InitTestAPIServer(t, "core-res-enqueue", nil),
+					0,
+					scheduler.WithPodInitialBackoffSeconds(0),
+					scheduler.WithPodMaxBackoffSeconds(0),
+				)
+				testutils.SyncSchedulerInformerFactory(testCtx)
+
+				defer testCtx.Scheduler.SchedulingQueue.Close()
+
+				cs, ns, ctx := testCtx.ClientSet, testCtx.NS.Name, testCtx.Ctx
+				// Create one Node with a taint.
+				if _, err := cs.CoreV1().Nodes().Create(ctx, tt.initialNode, metav1.CreateOptions{}); err != nil {
+					t.Fatalf("Failed to create an initial Node %q: %v", tt.initialNode.Name, err)
+				}
+
+				if tt.initialPod != nil {
+					if _, err := cs.CoreV1().Pods(ns).Create(ctx, tt.initialPod, metav1.CreateOptions{}); err != nil {
+						t.Fatalf("Failed to create an initial Pod %q: %v", tt.initialPod.Name, err)
+					}
+				}
+
+				for _, pod := range tt.pods {
+					if _, err := cs.CoreV1().Pods(ns).Create(ctx, pod, metav1.CreateOptions{}); err != nil {
+						t.Fatalf("Failed to create Pod %q: %v", pod.Name, err)
+					}
+				}
+
+				// Wait for the tt.pods to be present in the scheduling queue.
+				if err := wait.PollUntilContextTimeout(ctx, time.Millisecond*200, wait.ForeverTestTimeout, false, func(ctx context.Context) (bool, error) {
+					pendingPods, _ := testCtx.Scheduler.SchedulingQueue.PendingPods()
+					return len(pendingPods) == len(tt.pods), nil
+				}); err != nil {
+					t.Fatal(err)
+				}
+
+				t.Log("Confirmed Pods in the scheduling queue, starting to schedule them")
+
+				// Pop all pods out. They should be unschedulable.
+				for i := 0; i < len(tt.pods); i++ {
+					testCtx.Scheduler.ScheduleOne(testCtx.Ctx)
+				}
+				// Wait for the tt.pods to be still present in the scheduling queue.
+				if err := wait.PollUntilContextTimeout(ctx, time.Millisecond*200, wait.ForeverTestTimeout, false, func(ctx context.Context) (bool, error) {
+					pendingPods, _ := testCtx.Scheduler.SchedulingQueue.PendingPods()
+					return len(pendingPods) == len(tt.pods), nil
+				}); err != nil {
+					t.Fatal(err)
+				}
+
+				t.Log("finished initial schedulings for all Pods, will trigger triggerFn")
+
+				err := tt.triggerFn(testCtx)
+				if err != nil {
+					t.Fatalf("Failed to trigger the event: %v", err)
+				}
+
+				t.Log("triggered tt.triggerFn, will check if tt.requeuedPods are requeued")
+
+				// Wait for the tt.pods to be still present in the scheduling queue.
+				var requeuedPods sets.Set[string]
+				if err := wait.PollUntilContextTimeout(ctx, time.Millisecond*200, wait.ForeverTestTimeout, false, func(ctx context.Context) (bool, error) {
+					requeuedPods = sets.Set[string]{} // reset
+					for _, requeuedPod := range testCtx.Scheduler.SchedulingQueue.PodsInActiveQ() {
+						requeuedPods.Insert(requeuedPod.Name)
+					}
+
+					return requeuedPods.Equal(tt.wantRequeuedPods), nil
+				}); err != nil {
+					t.Fatalf("Expect Pods %v to be requeued, but %v are requeued actually", tt.wantRequeuedPods, requeuedPods)
+				}
+			})
 		}
 	}
-
-	// Wait for the three pods to be present in the scheduling queue.
-	if err := wait.PollUntilContextTimeout(ctx, time.Millisecond*200, wait.ForeverTestTimeout, false, func(ctx context.Context) (bool, error) {
-		pendingPods, _ := testCtx.Scheduler.SchedulingQueue.PendingPods()
-		return len(pendingPods) == 3, nil
-	}); err != nil {
-		t.Fatal(err)
-	}
-
-	// Pop the three pods out. They should be unschedulable.
-	for i := 0; i < 3; i++ {
-		podInfo := testutils.NextPodOrDie(t, testCtx)
-		fwk, ok := testCtx.Scheduler.Profiles[podInfo.Pod.Spec.SchedulerName]
-		if !ok {
-			t.Fatalf("Cannot find the profile for Pod %v", podInfo.Pod.Name)
-		}
-		// Schedule the Pod manually.
-		_, fitError := testCtx.Scheduler.SchedulePod(ctx, fwk, framework.NewCycleState(), podInfo.Pod)
-		if fitError == nil {
-			t.Fatalf("Expect Pod %v to fail at scheduling.", podInfo.Pod.Name)
-		}
-		testCtx.Scheduler.FailureHandler(ctx, fwk, podInfo, framework.NewStatus(framework.Unschedulable).WithError(fitError), nil, time.Now())
-	}
-
-	// Trigger a NodeTaintChange event.
-	// We expect this event to trigger moving the test Pod from unschedulablePods to activeQ.
-	node.Spec.Taints = nil
-	if _, err := cs.CoreV1().Nodes().Update(ctx, node, metav1.UpdateOptions{}); err != nil {
-		t.Fatalf("Failed to remove taints off the node: %v", err)
-	}
-
-	// Now we should be able to pop the Pod from activeQ again.
-	podInfo := testutils.NextPodOrDie(t, testCtx)
-	if podInfo.Attempts != 2 {
-		t.Fatalf("Expected the Pod to be attempted 2 times, but got %v", podInfo.Attempts)
-	}
-	if got := podInfo.Pod.Name; got != "pod1" {
-		t.Fatalf("Expected pod1 to be popped, but got %v", got)
-	}
-
-	// Pod2 and Pod3 are not expected to be popped out.
-	// - Although the failure reason has been lifted, Pod2 still won't be moved to active due to
-	//   the node event's preCheckForNode().
-	// - Regarding Pod3, the NodeTaintChange event is irrelevant with its scheduling failure.
-	podInfo = testutils.NextPod(t, testCtx)
-	if podInfo != nil {
-		t.Fatalf("Unexpected pod %v get popped out", podInfo.Pod.Name)
-	}
 }
 
 var _ framework.FilterPlugin = &fakeCRPlugin{}

test/integration/util/util.go

@@ -1159,6 +1159,8 @@ func NextPodOrDie(t *testing.T, testCtx *TestContext) *schedulerframework.Queued
 }
 
 // NextPod returns the next Pod in the scheduler queue, with a 5 seconds timeout.
+// Note that this function leaks goroutines in the case of timeout; even after this function returns after timeout,
+// the goroutine made by this function keep waiting to pop a pod from the queue.
 func NextPod(t *testing.T, testCtx *TestContext) *schedulerframework.QueuedPodInfo {
 	t.Helper()