implement QueueingHint in TaintToleration

pkg/scheduler/framework/plugins/tainttoleration/taint_toleration.go

@@ -23,9 +23,11 @@ import (
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	v1helper "k8s.io/component-helpers/scheduling/corev1"
+	"k8s.io/klog/v2"
 	"k8s.io/kubernetes/pkg/scheduler/framework"
 	"k8s.io/kubernetes/pkg/scheduler/framework/plugins/helper"
 	"k8s.io/kubernetes/pkg/scheduler/framework/plugins/names"
+	"k8s.io/kubernetes/pkg/scheduler/util"
 )
 
 // TaintToleration is a plugin that checks if a pod tolerates a node's taints.
@@ -56,10 +58,35 @@ func (pl *TaintToleration) Name() string {
 // failed by this plugin schedulable.
 func (pl *TaintToleration) EventsToRegister() []framework.ClusterEventWithHint {
 	return []framework.ClusterEventWithHint{
-		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.Update}},
+		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.Update}, QueueingHintFn: pl.isSchedulableAfterNodeChange},
 	}
 }
 
+// isSchedulableAfterNodeChange is invoked for all node events reported by
+// an informer. It checks whether that change made a previously unschedulable
+// pod schedulable.
+func (pl *TaintToleration) isSchedulableAfterNodeChange(logger klog.Logger, pod *v1.Pod, oldObj, newObj interface{}) (framework.QueueingHint, error) {
+	originalNode, modifiedNode, err := util.As[*v1.Node](oldObj, newObj)
+	if err != nil {
+		return framework.Queue, err
+	}
+
+	wasUntolerated := true
+	if originalNode != nil {
+		_, wasUntolerated = v1helper.FindMatchingUntoleratedTaint(originalNode.Spec.Taints, pod.Spec.Tolerations, helper.DoNotScheduleTaintsFilterFunc())
+	}
+
+	_, isUntolerated := v1helper.FindMatchingUntoleratedTaint(modifiedNode.Spec.Taints, pod.Spec.Tolerations, helper.DoNotScheduleTaintsFilterFunc())
+
+	if wasUntolerated && !isUntolerated {
+		logger.V(5).Info("node was created or updated, and this may make the Pod rejected by TaintToleration plugin in the previous scheduling cycle schedulable", "pod", klog.KObj(pod), "node", klog.KObj(modifiedNode))
+		return framework.Queue, nil
+	}
+
+	logger.V(5).Info("node was created or updated, but it doesn't change the TaintToleration plugin's decision", "pod", klog.KObj(pod), "node", klog.KObj(modifiedNode))
+	return framework.QueueSkip, nil
+}
+
 // Filter invoked at the filter extension point.
 func (pl *TaintToleration) Filter(ctx context.Context, state *framework.CycleState, pod *v1.Pod, nodeInfo *framework.NodeInfo) *framework.Status {
 	node := nodeInfo.Node()

pkg/scheduler/framework/plugins/tainttoleration/taint_toleration_test.go

@@ -353,3 +353,68 @@ func TestTaintTolerationFilter(t *testing.T) {
 		})
 	}
 }
+
+func TestIsSchedulableAfterNodeChange(t *testing.T) {
+	tests := []struct {
+		name         string
+		pod          *v1.Pod
+		oldObj       interface{}
+		newObj       interface{}
+		expectedHint framework.QueueingHint
+		wantErr      bool
+	}{
+		{
+			name:         "backoff-wrong-new-object",
+			newObj:       "not-a-node",
+			expectedHint: framework.Queue,
+			wantErr:      true,
+		},
+		{
+			name:         "backoff-wrong-old-object",
+			newObj:       nodeWithTaints("nodeA", []v1.Taint{{Key: "dedicated", Value: "user1", Effect: "NoSchedule"}}),
+			oldObj:       "not-a-node",
+			expectedHint: framework.Queue,
+			wantErr:      true,
+		},
+		{
+			name:         "skip-queue-on-untoleratedtaint-node-added",
+			pod:          podWithTolerations("pod1", []v1.Toleration{{Key: "dedicated", Operator: "Equal", Value: "user2", Effect: "NoSchedule"}}),
+			newObj:       nodeWithTaints("nodeA", []v1.Taint{{Key: "dedicated", Value: "user1", Effect: "NoSchedule"}}),
+			expectedHint: framework.QueueSkip,
+		},
+		{
+			name:         "queue-on-toleratedtaint-node-added",
+			pod:          podWithTolerations("pod1", []v1.Toleration{{Key: "dedicated", Operator: "Equal", Value: "user2", Effect: "NoSchedule"}}),
+			newObj:       nodeWithTaints("nodeA", []v1.Taint{{Key: "dedicated", Value: "user2", Effect: "NoSchedule"}}),
+			expectedHint: framework.Queue,
+		},
+		{
+			name:         "skip-unrelated-change",
+			pod:          podWithTolerations("pod1", []v1.Toleration{{Key: "dedicated", Operator: "Equal", Value: "user2", Effect: "NoSchedule"}}),
+			newObj:       nodeWithTaints("nodeA", []v1.Taint{{Key: "dedicated", Value: "user1", Effect: "NoSchedule"}, {Key: "dedicated", Value: "user3", Effect: "NoSchedule"}}),
+			oldObj:       nodeWithTaints("nodeA", []v1.Taint{{Key: "dedicated", Value: "user1", Effect: "NoSchedule"}}),
+			expectedHint: framework.QueueSkip,
+		},
+		{
+			name:         "queue-on-taint-change",
+			pod:          podWithTolerations("pod1", []v1.Toleration{{Key: "dedicated", Operator: "Equal", Value: "user2", Effect: "NoSchedule"}}),
+			newObj:       nodeWithTaints("nodeA", []v1.Taint{{Key: "dedicated", Value: "user2", Effect: "NoSchedule"}}),
+			oldObj:       nodeWithTaints("nodeA", []v1.Taint{{Key: "dedicated", Value: "user1", Effect: "NoSchedule"}}),
+			expectedHint: framework.Queue,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			logger, _ := ktesting.NewTestContext(t)
+			pl := &TaintToleration{}
+			got, err := pl.isSchedulableAfterNodeChange(logger, test.pod, test.oldObj, test.newObj)
+			if (err != nil) != test.wantErr {
+				t.Errorf("isSchedulableAfterNodeChange() error = %v, wantErr %v", err, test.wantErr)
+			}
+			if got != test.expectedHint {
+				t.Errorf("isSchedulableAfterNodeChange() = %v, want %v", got, test.expectedHint)
+			}
+		})
+	}
+}