volumezone: scheduler queueing hints

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

@@ -276,7 +276,7 @@ func (pl *VolumeZone) EventsToRegister() []framework.ClusterEventWithHint {
 	return []framework.ClusterEventWithHint{
 		// New storageClass with bind mode `VolumeBindingWaitForFirstConsumer` will make a pod schedulable.
 		// Due to immutable field `storageClass.volumeBindingMode`, storageClass update events are ignored.
-		{Event: framework.ClusterEvent{Resource: framework.StorageClass, ActionType: framework.Add}},
+		{Event: framework.ClusterEvent{Resource: framework.StorageClass, ActionType: framework.Add}, QueueingHintFn: pl.isSchedulableAfterStorageClassAdded},
 		// A new node or updating a node's volume zone labels may make a pod schedulable.
 		//
 		// A note about UpdateNodeTaint event:
@@ -342,6 +342,23 @@ func (pl *VolumeZone) isPVCRequestedFromPod(logger klog.Logger, pvc *v1.Persiste
 	return false
 }
 
+// isSchedulableAfterStorageClassAdded is invoked whenever a StorageClass is added.
+// It checks whether the addition of StorageClass has made a previously unschedulable pod schedulable.
+// Only a new StorageClass with WaitForFirstConsumer will cause a pod to become schedulable.
+func (pl *VolumeZone) isSchedulableAfterStorageClassAdded(logger klog.Logger, pod *v1.Pod, oldObj, newObj interface{}) (framework.QueueingHint, error) {
+	_, addedStorageClass, err := util.As[*storage.StorageClass](nil, newObj)
+	if err != nil {
+		return framework.Queue, fmt.Errorf("unexpected objects in isSchedulableAfterStorageClassAdded: %w", err)
+	}
+	if (addedStorageClass.VolumeBindingMode == nil) || (*addedStorageClass.VolumeBindingMode != storage.VolumeBindingWaitForFirstConsumer) {
+		logger.V(5).Info("StorageClass is created, but its VolumeBindingMode is not waitForFirstConsumer, which doesn't make the pod schedulable", "storageClass", klog.KObj(addedStorageClass), "pod", klog.KObj(pod))
+		return framework.QueueSkip, nil
+	}
+
+	logger.V(5).Info("StorageClass with waitForFirstConsumer mode was created and it might make this pod schedulable", "pod", klog.KObj(pod), "StorageClass", klog.KObj(addedStorageClass))
+	return framework.Queue, nil
+}
+
 // New initializes a new plugin and returns it.
 func New(_ context.Context, _ runtime.Object, handle framework.Handle) (framework.Plugin, error) {
 	informerFactory := handle.SharedInformerFactory()

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

@@ -627,6 +627,54 @@ func TestIsSchedulableAfterPersistentVolumeClaimAdded(t *testing.T) {
 	}
 }
 
+func TestIsSchedulableAfterStorageClassAdded(t *testing.T) {
+	var modeWait = storagev1.VolumeBindingWaitForFirstConsumer
+
+	testcases := map[string]struct {
+		pod            *v1.Pod
+		oldObj, newObj interface{}
+		expectedHint   framework.QueueingHint
+		expectedErr    bool
+	}{
+		"error-wrong-new-object": {
+			pod:          createPodWithVolume("pod_1", "PVC_1"),
+			newObj:       "not-a-storageclass",
+			expectedHint: framework.Queue,
+			expectedErr:  true,
+		},
+		"sc-doesn't-have-volume-binding-mode": {
+			pod: createPodWithVolume("pod_1", "PVC_1"),
+			newObj: &storagev1.StorageClass{
+				ObjectMeta: metav1.ObjectMeta{Name: "SC_1"},
+			},
+			expectedHint: framework.QueueSkip,
+		},
+		"new-sc-is-wait-for-first-consumer-mode": {
+			pod: createPodWithVolume("pod_1", "PVC_1"),
+			newObj: &storagev1.StorageClass{
+				ObjectMeta:        metav1.ObjectMeta{Name: "SC_1"},
+				VolumeBindingMode: &modeWait,
+			},
+			expectedHint: framework.Queue,
+		},
+	}
+
+	for name, tc := range testcases {
+		t.Run(name, func(t *testing.T) {
+			logger, _ := ktesting.NewTestContext(t)
+			p := &VolumeZone{}
+
+			got, err := p.isSchedulableAfterStorageClassAdded(logger, tc.pod, tc.oldObj, tc.newObj)
+			if err != nil && !tc.expectedErr {
+				t.Errorf("unexpected error: %v", err)
+			}
+			if got != tc.expectedHint {
+				t.Errorf("isSchedulableAfterStorageClassAdded() = %v, want %v", got, tc.expectedHint)
+			}
+		})
+	}
+}
+
 func BenchmarkVolumeZone(b *testing.B) {
 	tests := []struct {
 		Name      string