podtopologyspread: scheduler queueing hints

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

@@ -19,18 +19,22 @@ package podtopologyspread
 import (
 	"context"
 	"fmt"
+	"reflect"
 
 	v1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/client-go/informers"
 	appslisters "k8s.io/client-go/listers/apps/v1"
 	corelisters "k8s.io/client-go/listers/core/v1"
+	"k8s.io/klog/v2"
 	"k8s.io/kubernetes/pkg/scheduler/apis/config"
 	"k8s.io/kubernetes/pkg/scheduler/apis/config/validation"
 	"k8s.io/kubernetes/pkg/scheduler/framework"
 	"k8s.io/kubernetes/pkg/scheduler/framework/parallelize"
 	"k8s.io/kubernetes/pkg/scheduler/framework/plugins/feature"
 	"k8s.io/kubernetes/pkg/scheduler/framework/plugins/names"
+	"k8s.io/kubernetes/pkg/scheduler/util"
 )
 
 const (
@@ -66,6 +70,10 @@ type PodTopologySpread struct {
 	enableMinDomainsInPodTopologySpread          bool
 	enableNodeInclusionPolicyInPodTopologySpread bool
 	enableMatchLabelKeysInPodTopologySpread      bool
+
+	// logger is only meant to be used by background activities which don't
+	// have some other logger in their parent callstack.
+	logger klog.Logger
 }
 
 var _ framework.PreFilterPlugin = &PodTopologySpread{}
@@ -141,9 +149,119 @@ func (pl *PodTopologySpread) EventsToRegister() []framework.ClusterEventWithHint
 		// an unschedulable Pod schedulable.
 		// - Delete. An unschedulable Pod may fail due to violating an existing Pod's topology spread constraints,
 		// deleting an existing Pod may make it schedulable.
-		{Event: framework.ClusterEvent{Resource: framework.Pod, ActionType: framework.All}},
+		{Event: framework.ClusterEvent{Resource: framework.Pod, ActionType: framework.All}, QueueingHintFn: pl.isSchedulableAfterPodChange},
 		// Node add|delete|updateLabel 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.UpdateNodeLabel}},
+		{Event: framework.ClusterEvent{Resource: framework.Node, ActionType: framework.Add | framework.Delete | framework.UpdateNodeLabel}, QueueingHintFn: pl.isSchedulableAfterNodeChange},
+	}
+}
+
+func (pl *PodTopologySpread) isSchedulableAfterPodChange(logger klog.Logger, pod *v1.Pod, oldObj, newObj interface{}) (framework.QueueingHint, error) {
+	originalPod, modifiedPod, err := util.As[*v1.Pod](oldObj, newObj)
+	if err != nil {
+		pl.logger.Error(err, "unexpected objects in isSchedulableAfterPodChange", "oldObj", oldObj, "newObj", newObj)
+		return framework.Queue, err
+	}
+
+	constraints, err := pl.getConstraints(pod)
+	if err != nil {
+		pl.logger.Error(err, "get constraints from pod failed:", "pod", klog.KObj(pod))
+		return framework.Queue, err
+	}
+
+	if modifiedPod != nil && originalPod != nil && !reflect.DeepEqual(modifiedPod.Labels, originalPod.Labels) {
+		for _, c := range constraints {
+			if c.Selector.Matches(labels.Set(originalPod.Labels)) || c.Selector.Matches(labels.Set(modifiedPod.Labels)) {
+				return framework.Queue, nil
+			}
+		}
+		return framework.QueueSkip, nil
 	}
+
+	if originalPod != nil {
+		for _, c := range constraints {
+			if c.Selector.Matches(labels.Set(originalPod.Labels)) {
+				return framework.Queue, nil
+			}
+		}
+	}
+
+	if modifiedPod != nil {
+		for _, c := range constraints {
+			if c.Selector.Matches(labels.Set(modifiedPod.Labels)) {
+				return framework.Queue, nil
+			}
+		}
+	}
+
+	return framework.QueueSkip, nil
+}
+
+func (pl *PodTopologySpread) getConstraints(pod *v1.Pod) ([]topologySpreadConstraint, error) {
+	var constraints []topologySpreadConstraint
+	var err error
+	if len(pod.Spec.TopologySpreadConstraints) > 0 {
+		// We have feature gating in APIServer to strip the spec
+		// so don't need to re-check feature gate, just check length of Constraints.
+		constraints, err = pl.filterTopologySpreadConstraints(
+			pod.Spec.TopologySpreadConstraints,
+			pod.Labels,
+			v1.DoNotSchedule,
+		)
+		if err != nil {
+			return nil, fmt.Errorf("obtaining pod's hard topology spread constraints: %w", err)
+		}
+	} else {
+		constraints, err = pl.buildDefaultConstraints(pod, v1.DoNotSchedule)
+		if err != nil {
+			return nil, fmt.Errorf("setting default hard topology spread constraints: %w", err)
+		}
+	}
+	return constraints, nil
+}
+
+func (pl *PodTopologySpread) 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 {
+		pl.logger.Error(err, "unexpected objects in isSchedulableAfterNodeChange", "oldObj", oldObj, "newObj", newObj)
+		return framework.Queue, err
+	}
+
+	constraints, err := pl.getConstraints(pod)
+	if err != nil {
+		pl.logger.Error(err, "get constraints from pod failed:", "pod", klog.KObj(pod))
+		return framework.Queue, err
+	}
+
+	// framework.UpdateNodeLabel: return Queue when topologyKey is added/removed in node's labels, else return QueueSkip.
+	if originalNode != nil && modifiedNode != nil {
+		pl.logger.V(4).Info("node was updated", "pod", klog.KObj(pod), "node", klog.KObj(modifiedNode))
+		if nodeLabelsMatchSpreadConstraints(originalNode.Labels, constraints) {
+			return framework.Queue, nil
+		}
+		if nodeLabelsMatchSpreadConstraints(modifiedNode.Labels, constraints) {
+			return framework.Queue, nil
+		}
+		return framework.QueueSkip, nil
+	}
+
+	// framework.Add: return Queue when node has topologyKey in its labels, else return QueueSkip.
+	if modifiedNode != nil {
+		pl.logger.V(4).Info("node was created", "pod", klog.KObj(pod))
+		if !nodeLabelsMatchSpreadConstraints(modifiedNode.Labels, constraints) {
+			return framework.QueueSkip, nil
+		}
+		return framework.Queue, nil
+	}
+
+	// framework.Delete: return Queue when node has topologyKey in its labels, else return QueueSkip.
+	if originalNode != nil {
+		pl.logger.V(4).Info("node was deleted", "pod", klog.KObj(pod))
+		if !nodeLabelsMatchSpreadConstraints(originalNode.Labels, constraints) {
+			return framework.QueueSkip, nil
+		}
+		return framework.Queue, nil
+	}
+
+	return framework.QueueSkip, nil
 }