Merge pull request #1816 from ingvagabund/prometheus-client-update-test

test(pkg/descheduler): test a prometheus client update propagates to a plugin profile handle

CONTRIBUTING-descheduler.md

@@ -20,3 +20,11 @@ These are the known conventions that are useful to practice whenever reasonable:
 * *no object instance duplication*: avoid duplication by no creating two objects with the same passed values at two different places. E.g. two nodes created with the same memory, cpu and pods requests. Rather create a single function wrapping test.BuildTestNode and invoke this wrapper multiple times.
 
 The aim is to reduce cognitive load when reading and debugging the test code.
+
+## Design Decisions FAQ
+
+This section documents common questions about design decisions in the descheduler codebase and the rationale behind them.
+
+### Why doesn't the framework provide helpers for registering and retrieving indexers for plugins?
+
+In general, each plugin can have many indexers—for example, for nodes, namespaces, pods, and other resources. Each plugin, depending on its internal optimizations, may choose a different indexing function. Indexers are currently used very rarely in the framework and default plugins. Therefore, extending the framework interface with additional helpers for registering and retrieving indexers might introduce an unnecessary and overly restrictive layer without first understanding how indexers will be used. For the moment, I suggest avoiding any restrictions on how many indexers can be registered or which ones can be registered. Instead, we should extend the framework handle to provide a unique ID for each profile, so that indexers within the same profile share a unique prefix. This avoids collisions when the same profile is instantiated more than once. Later, once we learn more about indexer usage, we can revisit whether it makes sense to impose additional restrictions.

pkg/api/v1alpha2/zz_generated.conversion.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/api/v1alpha2/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/api/v1alpha2/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/api/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/apis/componentconfig/v1alpha1/zz_generated.conversion.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/apis/componentconfig/v1alpha1/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/apis/componentconfig/v1alpha1/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/apis/componentconfig/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/descheduler/descheduler.go

@@ -30,14 +30,9 @@ import (
 	"go.opentelemetry.io/otel/trace"
 
 	v1 "k8s.io/api/core/v1"
-	policy "k8s.io/api/policy/v1"
-	policyv1 "k8s.io/api/policy/v1"
-	schedulingv1 "k8s.io/api/scheduling/v1"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/labels"
-	"k8s.io/apimachinery/pkg/runtime"
-	"k8s.io/apimachinery/pkg/runtime/schema"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	utilversion "k8s.io/apimachinery/pkg/util/version"
 	"k8s.io/apimachinery/pkg/util/wait"
@@ -47,7 +42,6 @@ import (
 	fakeclientset "k8s.io/client-go/kubernetes/fake"
 	corev1listers "k8s.io/client-go/listers/core/v1"
 	"k8s.io/client-go/rest"
-	core "k8s.io/client-go/testing"
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/events"
 	"k8s.io/client-go/util/workqueue"
@@ -74,6 +68,7 @@ import (
 const (
 	prometheusAuthTokenSecretKey = "prometheusAuthToken"
 	workQueueKey                 = "key"
+	indexerNodeSelectorGlobal    = "indexer_node_selector_global"
 )
 
 type eprunner func(ctx context.Context, nodes []*v1.Node) *frameworktypes.Status
@@ -85,14 +80,14 @@ type profileRunner struct {
 
 type descheduler struct {
 	rs                                *options.DeschedulerServer
-	ir                                *informerResources
+	client                            clientset.Interface
+	kubeClientSandbox                 *kubeClientSandbox
 	getPodsAssignedToNode             podutil.GetPodsAssignedToNodeFunc
 	sharedInformerFactory             informers.SharedInformerFactory
 	namespacedSecretsLister           corev1listers.SecretNamespaceLister
 	deschedulerPolicy                 *api.DeschedulerPolicy
 	eventRecorder                     events.EventRecorder
 	podEvictor                        *evictions.PodEvictor
-	podEvictionReactionFnc            func(*fakeclientset.Clientset) func(action core.Action) (bool, runtime.Object, error)
 	metricsCollector                  *metricscollector.MetricsCollector
 	prometheusClient                  promapi.Client
 	previousPrometheusClientTransport *http.Transport
@@ -101,48 +96,20 @@ type descheduler struct {
 	metricsProviders                  map[api.MetricsSource]*api.MetricsProvider
 }
 
-type informerResources struct {
-	sharedInformerFactory informers.SharedInformerFactory
-	resourceToInformer    map[schema.GroupVersionResource]informers.GenericInformer
+func nodeSelectorFromPolicy(deschedulerPolicy *api.DeschedulerPolicy) (labels.Selector, error) {
+	nodeSelector := labels.Everything()
+	if deschedulerPolicy.NodeSelector != nil {
+		sel, err := labels.Parse(*deschedulerPolicy.NodeSelector)
+		if err != nil {
+			return nil, err
+		}
+		nodeSelector = sel
+	}
+	return nodeSelector, nil
 }
 
-func newInformerResources(sharedInformerFactory informers.SharedInformerFactory) *informerResources {
-	return &informerResources{
-		sharedInformerFactory: sharedInformerFactory,
-		resourceToInformer:    make(map[schema.GroupVersionResource]informers.GenericInformer),
-	}
-}
-
-func (ir *informerResources) Uses(resources ...schema.GroupVersionResource) error {
-	for _, resource := range resources {
-		informer, err := ir.sharedInformerFactory.ForResource(resource)
-		if err != nil {
-			return err
-		}
-
-		ir.resourceToInformer[resource] = informer
-	}
-	return nil
-}
-
-// CopyTo Copy informer subscriptions to the new factory and objects to the fake client so that the backing caches are populated for when listers are used.
-func (ir *informerResources) CopyTo(fakeClient *fakeclientset.Clientset, newFactory informers.SharedInformerFactory) error {
-	for resource, informer := range ir.resourceToInformer {
-		_, err := newFactory.ForResource(resource)
-		if err != nil {
-			return fmt.Errorf("error getting resource %s: %w", resource, err)
-		}
-
-		objects, err := informer.Lister().List(labels.Everything())
-		if err != nil {
-			return fmt.Errorf("error listing %s: %w", informer, err)
-		}
-
-		for _, object := range objects {
-			fakeClient.Tracker().Add(object)
-		}
-	}
-	return nil
+func addNodeSelectorIndexer(sharedInformerFactory informers.SharedInformerFactory, nodeSelector labels.Selector) error {
+	return nodeutil.AddNodeSelectorIndexer(sharedInformerFactory.Core().V1().Nodes().Informer(), indexerNodeSelectorGlobal, nodeSelector)
 }
 
 func metricsProviderListToMap(providersList []api.MetricsProvider) map[api.MetricsSource]*api.MetricsProvider {
@@ -153,19 +120,28 @@ func metricsProviderListToMap(providersList []api.MetricsProvider) map[api.Metri
 	return providersMap
 }
 
-func newDescheduler(ctx context.Context, rs *options.DeschedulerServer, deschedulerPolicy *api.DeschedulerPolicy, evictionPolicyGroupVersion string, eventRecorder events.EventRecorder, sharedInformerFactory, namespacedSharedInformerFactory informers.SharedInformerFactory) (*descheduler, error) {
-	podInformer := sharedInformerFactory.Core().V1().Pods().Informer()
+// setupPrometheusProvider sets up the prometheus provider on the descheduler if configured
+func setupPrometheusProvider(d *descheduler, namespacedSharedInformerFactory informers.SharedInformerFactory) error {
+	prometheusProvider := d.metricsProviders[api.PrometheusMetrics]
+	if prometheusProvider != nil && prometheusProvider.Prometheus != nil && prometheusProvider.Prometheus.AuthToken != nil {
+		authTokenSecret := prometheusProvider.Prometheus.AuthToken.SecretReference
+		if authTokenSecret == nil || authTokenSecret.Namespace == "" {
+			return fmt.Errorf("prometheus metrics source configuration is missing authentication token secret")
+		}
+		if namespacedSharedInformerFactory == nil {
+			return fmt.Errorf("namespacedSharedInformerFactory not configured")
+		}
+		namespacedSharedInformerFactory.Core().V1().Secrets().Informer().AddEventHandler(d.eventHandler())
+		d.namespacedSecretsLister = namespacedSharedInformerFactory.Core().V1().Secrets().Lister().Secrets(authTokenSecret.Namespace)
+	}
+	return nil
+}
 
-	ir := newInformerResources(sharedInformerFactory)
-	ir.Uses(v1.SchemeGroupVersion.WithResource("pods"),
-		v1.SchemeGroupVersion.WithResource("nodes"),
-		// Future work could be to let each plugin declare what type of resources it needs; that way dry runs would stay
-		// consistent with the real runs without having to keep the list here in sync.
-		v1.SchemeGroupVersion.WithResource("namespaces"),                 // Used by the defaultevictor plugin
-		schedulingv1.SchemeGroupVersion.WithResource("priorityclasses"),  // Used by the defaultevictor plugin
-		policyv1.SchemeGroupVersion.WithResource("poddisruptionbudgets"), // Used by the defaultevictor plugin
-		v1.SchemeGroupVersion.WithResource("persistentvolumeclaims"),     // Used by the defaultevictor plugin
-	) // Used by the defaultevictor plugin
+func newDescheduler(ctx context.Context, rs *options.DeschedulerServer, deschedulerPolicy *api.DeschedulerPolicy, evictionPolicyGroupVersion string, eventRecorder events.EventRecorder, client clientset.Interface, sharedInformerFactory informers.SharedInformerFactory, kubeClientSandbox *kubeClientSandbox) (*descheduler, error) {
+	podInformer := sharedInformerFactory.Core().V1().Pods().Informer()
+	// Temporarily register the PVC because it is used by the DefaultEvictor plugin during
+	// the descheduling cycle, where informer registration is ignored.
+	_ = sharedInformerFactory.Core().V1().PersistentVolumeClaims().Informer()
 
 	getPodsAssignedToNode, err := podutil.BuildGetPodsAssignedToNodeFunc(podInformer)
 	if err != nil {
@@ -174,7 +150,7 @@ func newDescheduler(ctx context.Context, rs *options.DeschedulerServer, deschedu
 
 	podEvictor, err := evictions.NewPodEvictor(
 		ctx,
-		rs.Client,
+		client,
 		eventRecorder,
 		podInformer,
 		rs.DefaultFeatureGates,
@@ -194,41 +170,29 @@ func newDescheduler(ctx context.Context, rs *options.DeschedulerServer, deschedu
 
 	desch := &descheduler{
 		rs:                    rs,
-		ir:                     ir,
+		client:                client,
+		kubeClientSandbox:     kubeClientSandbox,
 		getPodsAssignedToNode: getPodsAssignedToNode,
 		sharedInformerFactory: sharedInformerFactory,
 		deschedulerPolicy:     deschedulerPolicy,
 		eventRecorder:         eventRecorder,
 		podEvictor:            podEvictor,
-		podEvictionReactionFnc: podEvictionReactionFnc,
 		prometheusClient:      rs.PrometheusClient,
 		queue:                 workqueue.NewRateLimitingQueueWithConfig(workqueue.DefaultControllerRateLimiter(), workqueue.RateLimitingQueueConfig{Name: "descheduler"}),
 		metricsProviders:      metricsProviderListToMap(deschedulerPolicy.MetricsProviders),
 	}
 
-	if rs.MetricsClient != nil {
-		nodeSelector := labels.Everything()
-		if deschedulerPolicy.NodeSelector != nil {
-			sel, err := labels.Parse(*deschedulerPolicy.NodeSelector)
+	nodeSelector, err := nodeSelectorFromPolicy(deschedulerPolicy)
 	if err != nil {
 		return nil, err
 	}
-			nodeSelector = sel
-		}
-		desch.metricsCollector = metricscollector.NewMetricsCollector(sharedInformerFactory.Core().V1().Nodes().Lister(), rs.MetricsClient, nodeSelector)
+
+	if err := addNodeSelectorIndexer(sharedInformerFactory, nodeSelector); err != nil {
+		return nil, err
 	}
 
-	prometheusProvider := desch.metricsProviders[api.PrometheusMetrics]
-	if prometheusProvider != nil && prometheusProvider.Prometheus != nil && prometheusProvider.Prometheus.AuthToken != nil {
-		authTokenSecret := prometheusProvider.Prometheus.AuthToken.SecretReference
-		if authTokenSecret == nil || authTokenSecret.Namespace == "" {
-			return nil, fmt.Errorf("prometheus metrics source configuration is missing authentication token secret")
-		}
-		if namespacedSharedInformerFactory == nil {
-			return nil, fmt.Errorf("namespacedSharedInformerFactory not configured")
-		}
-		namespacedSharedInformerFactory.Core().V1().Secrets().Informer().AddEventHandler(desch.eventHandler())
-		desch.namespacedSecretsLister = namespacedSharedInformerFactory.Core().V1().Secrets().Lister().Secrets(authTokenSecret.Namespace)
+	if rs.MetricsClient != nil {
+		desch.metricsCollector = metricscollector.NewMetricsCollector(sharedInformerFactory.Core().V1().Nodes().Lister(), rs.MetricsClient, nodeSelector)
 	}
 
 	return desch, nil
@@ -345,7 +309,7 @@ func (d *descheduler) eventHandler() cache.ResourceEventHandler {
 	}
 }
 
-func (d *descheduler) runDeschedulerLoop(ctx context.Context, nodes []*v1.Node) error {
+func (d *descheduler) runDeschedulerLoop(ctx context.Context) error {
 	var span trace.Span
 	ctx, span = tracing.Tracer().Start(ctx, "runDeschedulerLoop")
 	defer span.End()
@@ -354,52 +318,22 @@ func (d *descheduler) runDeschedulerLoop(ctx context.Context, nodes []*v1.Node)
 		metrics.LoopDuration.With(map[string]string{}).Observe(time.Since(loopStartDuration).Seconds())
 	}(time.Now())
 
-	// if len is still <= 1 error out
-	if len(nodes) <= 1 {
-		klog.InfoS("Skipping descheduling cycle: requires >=2 nodes", "found", len(nodes))
-		return nil // gracefully skip this cycle instead of aborting
-	}
-
-	var client clientset.Interface
-	// When the dry mode is enable, collect all the relevant objects (mostly pods) under a fake client.
-	// So when evicting pods while running multiple strategies in a row have the cummulative effect
-	// as is when evicting pods for real.
-	if d.rs.DryRun {
-		klog.V(3).Infof("Building a cached client from the cluster for the dry run")
-		// Create a new cache so we start from scratch without any leftovers
-		fakeClient := fakeclientset.NewSimpleClientset()
-		// simulate a pod eviction by deleting a pod
-		fakeClient.PrependReactor("create", "pods", d.podEvictionReactionFnc(fakeClient))
-		fakeSharedInformerFactory := informers.NewSharedInformerFactory(fakeClient, 0)
-
-		err := d.ir.CopyTo(fakeClient, fakeSharedInformerFactory)
-		if err != nil {
-			return err
-		}
-
-		// create a new instance of the shared informer factor from the cached client
-		// register the pod informer, otherwise it will not get running
-		d.getPodsAssignedToNode, err = podutil.BuildGetPodsAssignedToNodeFunc(fakeSharedInformerFactory.Core().V1().Pods().Informer())
-		if err != nil {
-			return fmt.Errorf("build get pods assigned to node function error: %v", err)
-		}
-
-		fakeCtx, cncl := context.WithCancel(context.TODO())
-		defer cncl()
-		fakeSharedInformerFactory.Start(fakeCtx.Done())
-		fakeSharedInformerFactory.WaitForCacheSync(fakeCtx.Done())
-
-		client = fakeClient
-		d.sharedInformerFactory = fakeSharedInformerFactory
-	} else {
-		client = d.rs.Client
-	}
-
-	klog.V(3).Infof("Setting up the pod evictor")
-	d.podEvictor.SetClient(client)
+	klog.V(3).Infof("Resetting pod evictor counters")
 	d.podEvictor.ResetCounters()
 
-	d.runProfiles(ctx, client, nodes)
+	d.runProfiles(ctx)
+
+	if d.rs.DryRun {
+		if d.kubeClientSandbox == nil {
+			return fmt.Errorf("kubeClientSandbox is nil in DryRun mode")
+		}
+		klog.V(3).Infof("Restoring evicted pods from cache")
+		if err := d.kubeClientSandbox.restoreEvictedPods(ctx); err != nil {
+			klog.ErrorS(err, "Failed to restore evicted pods")
+			return fmt.Errorf("failed to restore evicted pods: %w", err)
+		}
+		d.kubeClientSandbox.reset()
+	}
 
 	klog.V(1).InfoS("Number of evictions/requests", "totalEvicted", d.podEvictor.TotalEvicted(), "evictionRequests", d.podEvictor.TotalEvictionRequests())
 
@@ -409,22 +343,46 @@ func (d *descheduler) runDeschedulerLoop(ctx context.Context, nodes []*v1.Node)
 // runProfiles runs all the deschedule plugins of all profiles and
 // later runs through all balance plugins of all profiles. (All Balance plugins should come after all Deschedule plugins)
 // see https://github.com/kubernetes-sigs/descheduler/issues/979
-func (d *descheduler) runProfiles(ctx context.Context, client clientset.Interface, nodes []*v1.Node) {
+func (d *descheduler) runProfiles(ctx context.Context) {
 	var span trace.Span
 	ctx, span = tracing.Tracer().Start(ctx, "runProfiles")
 	defer span.End()
+
+	nodesAsInterface, err := d.sharedInformerFactory.Core().V1().Nodes().Informer().GetIndexer().ByIndex(indexerNodeSelectorGlobal, indexerNodeSelectorGlobal)
+	if err != nil {
+		span.AddEvent("Failed to list nodes with global node selector", trace.WithAttributes(attribute.String("err", err.Error())))
+		klog.Error(err)
+		return
+	}
+
+	nodes, err := nodeutil.ReadyNodesFromInterfaces(nodesAsInterface)
+	if err != nil {
+		span.AddEvent("Failed to convert node as interfaces into ready nodes", trace.WithAttributes(attribute.String("err", err.Error())))
+		klog.Error(err)
+		return
+	}
+
+	// if len is still <= 1 error out
+	if len(nodes) <= 1 {
+		klog.InfoS("Skipping descheduling cycle: requires >=2 nodes", "found", len(nodes))
+		return // gracefully skip this cycle instead of aborting
+	}
+
 	var profileRunners []profileRunner
-	for _, profile := range d.deschedulerPolicy.Profiles {
+	for idx, profile := range d.deschedulerPolicy.Profiles {
 		currProfile, err := frameworkprofile.NewProfile(
 			ctx,
 			profile,
 			pluginregistry.PluginRegistry,
-			frameworkprofile.WithClientSet(client),
+			frameworkprofile.WithClientSet(d.client),
 			frameworkprofile.WithSharedInformerFactory(d.sharedInformerFactory),
 			frameworkprofile.WithPodEvictor(d.podEvictor),
 			frameworkprofile.WithGetPodsAssignedToNodeFnc(d.getPodsAssignedToNode),
 			frameworkprofile.WithMetricsCollector(d.metricsCollector),
 			frameworkprofile.WithPrometheusClient(d.prometheusClient),
+			// Generate a unique instance ID using just the index to avoid long IDs
+			// when profile names are very long
+			frameworkprofile.WithProfileInstanceID(fmt.Sprintf("%d", idx)),
 		)
 		if err != nil {
 			klog.ErrorS(err, "unable to create a profile", "profile", profile.Name)
@@ -551,27 +509,6 @@ func validateVersionCompatibility(discovery discovery.DiscoveryInterface, desche
 	return nil
 }
 
-func podEvictionReactionFnc(fakeClient *fakeclientset.Clientset) func(action core.Action) (bool, runtime.Object, error) {
-	return func(action core.Action) (bool, runtime.Object, error) {
-		if action.GetSubresource() == "eviction" {
-			createAct, matched := action.(core.CreateActionImpl)
-			if !matched {
-				return false, nil, fmt.Errorf("unable to convert action to core.CreateActionImpl")
-			}
-			eviction, matched := createAct.Object.(*policy.Eviction)
-			if !matched {
-				return false, nil, fmt.Errorf("unable to convert action object into *policy.Eviction")
-			}
-			if err := fakeClient.Tracker().Delete(action.GetResource(), eviction.GetNamespace(), eviction.GetName()); err != nil {
-				return false, nil, fmt.Errorf("unable to delete pod %v/%v: %v", eviction.GetNamespace(), eviction.GetName(), err)
-			}
-			return true, nil, nil
-		}
-		// fallback to the default reactor
-		return false, nil, nil
-	}
-}
-
 type tokenReconciliation int
 
 const (
@@ -587,11 +524,6 @@ func RunDeschedulerStrategies(ctx context.Context, rs *options.DeschedulerServer
 
 	sharedInformerFactory := informers.NewSharedInformerFactoryWithOptions(rs.Client, 0, informers.WithTransform(trimManagedFields))
 
-	var nodeSelector string
-	if deschedulerPolicy.NodeSelector != nil {
-		nodeSelector = *deschedulerPolicy.NodeSelector
-	}
-
 	var eventClient clientset.Interface
 	if rs.DryRun {
 		eventClient = fakeclientset.NewSimpleClientset()
@@ -616,7 +548,8 @@ func RunDeschedulerStrategies(ctx context.Context, rs *options.DeschedulerServer
 		}
 	}
 
-	descheduler, err := newDescheduler(ctx, rs, deschedulerPolicy, evictionPolicyGroupVersion, eventRecorder, sharedInformerFactory, namespacedSharedInformerFactory)
+	// Always create descheduler with real client/factory first to register all informers
+	descheduler, err := newDescheduler(ctx, rs, deschedulerPolicy, evictionPolicyGroupVersion, eventRecorder, rs.Client, sharedInformerFactory, nil)
 	if err != nil {
 		span.AddEvent("Failed to create new descheduler", trace.WithAttributes(attribute.String("err", err.Error())))
 		return err
@@ -624,17 +557,52 @@ func RunDeschedulerStrategies(ctx context.Context, rs *options.DeschedulerServer
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
+	// Setup Prometheus provider (only for real client case, not for dry run)
+	if err := setupPrometheusProvider(descheduler, namespacedSharedInformerFactory); err != nil {
+		span.AddEvent("Failed to setup Prometheus provider", trace.WithAttributes(attribute.String("err", err.Error())))
+		return err
+	}
+
+	// If in dry run mode, replace the descheduler with one using fake client/factory
+	if rs.DryRun {
+		// Create sandbox with resources to mirror from real client
+		kubeClientSandbox, err := newDefaultKubeClientSandbox(rs.Client, sharedInformerFactory)
+		if err != nil {
+			span.AddEvent("Failed to create kube client sandbox", trace.WithAttributes(attribute.String("err", err.Error())))
+			return fmt.Errorf("failed to create kube client sandbox: %v", err)
+		}
+
+		klog.V(3).Infof("Building a cached client from the cluster for the dry run")
+
+		// TODO(ingvagabund): drop the previous queue
+		// TODO(ingvagabund): stop the previous pod evictor
+		// Replace descheduler with one using fake client/factory
+		descheduler, err = newDescheduler(ctx, rs, deschedulerPolicy, evictionPolicyGroupVersion, eventRecorder, kubeClientSandbox.fakeClient(), kubeClientSandbox.fakeSharedInformerFactory(), kubeClientSandbox)
+		if err != nil {
+			span.AddEvent("Failed to create dry run descheduler", trace.WithAttributes(attribute.String("err", err.Error())))
+			return err
+		}
+	}
+
+	// In dry run mode, start and sync the fake shared informer factory so it can mirror
+	// events from the real factory. Reliable propagation depends on both factories being
+	// fully synced (see WaitForCacheSync calls below), not solely on startup order.
+	if rs.DryRun {
+		descheduler.kubeClientSandbox.fakeSharedInformerFactory().Start(ctx.Done())
+		descheduler.kubeClientSandbox.fakeSharedInformerFactory().WaitForCacheSync(ctx.Done())
+	}
 	sharedInformerFactory.Start(ctx.Done())
 	if metricProviderTokenReconciliation == secretReconciliation {
 		namespacedSharedInformerFactory.Start(ctx.Done())
 	}
 
 	sharedInformerFactory.WaitForCacheSync(ctx.Done())
-	descheduler.podEvictor.WaitForEventHandlersSync(ctx)
 	if metricProviderTokenReconciliation == secretReconciliation {
 		namespacedSharedInformerFactory.WaitForCacheSync(ctx.Done())
 	}
 
+	descheduler.podEvictor.WaitForEventHandlersSync(ctx)
+
 	if descheduler.metricsCollector != nil {
 		go func() {
 			klog.V(2).Infof("Starting metrics collector")
@@ -666,14 +634,7 @@ func RunDeschedulerStrategies(ctx context.Context, rs *options.DeschedulerServer
 		sCtx, sSpan := tracing.Tracer().Start(ctx, "NonSlidingUntil")
 		defer sSpan.End()
 
-		nodes, err := nodeutil.ReadyNodes(sCtx, rs.Client, descheduler.sharedInformerFactory.Core().V1().Nodes().Lister(), nodeSelector)
-		if err != nil {
-			sSpan.AddEvent("Failed to detect ready nodes", trace.WithAttributes(attribute.String("err", err.Error())))
-			klog.Error(err)
-			cancel()
-			return
-		}
-		err = descheduler.runDeschedulerLoop(sCtx, nodes)
+		err = descheduler.runDeschedulerLoop(sCtx)
 		if err != nil {
 			sSpan.AddEvent("Failed to run descheduler loop", trace.WithAttributes(attribute.String("err", err.Error())))
 			klog.Error(err)

pkg/descheduler/descheduler_test.go

@@ -6,20 +6,27 @@ import (
 	"fmt"
 	"math/rand"
 	"net/http"
+	"net/url"
+	"strings"
 	"testing"
 	"time"
 
+	promapi "github.com/prometheus/client_golang/api"
 	v1 "k8s.io/api/core/v1"
 	policy "k8s.io/api/policy/v1"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/api/meta"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apimachinery/pkg/util/wait"
 	apiversion "k8s.io/apimachinery/pkg/version"
 	fakediscovery "k8s.io/client-go/discovery/fake"
 	"k8s.io/client-go/informers"
 	fakeclientset "k8s.io/client-go/kubernetes/fake"
 	core "k8s.io/client-go/testing"
+	"k8s.io/client-go/tools/cache"
 	"k8s.io/component-base/featuregate"
 	"k8s.io/klog/v2"
 	"k8s.io/metrics/pkg/apis/metrics/v1beta1"
@@ -31,16 +38,32 @@ import (
 	"sigs.k8s.io/descheduler/pkg/api"
 	"sigs.k8s.io/descheduler/pkg/descheduler/evictions"
 	"sigs.k8s.io/descheduler/pkg/features"
+	fakeplugin "sigs.k8s.io/descheduler/pkg/framework/fake/plugin"
 	"sigs.k8s.io/descheduler/pkg/framework/pluginregistry"
 	"sigs.k8s.io/descheduler/pkg/framework/plugins/defaultevictor"
 	"sigs.k8s.io/descheduler/pkg/framework/plugins/nodeutilization"
 	"sigs.k8s.io/descheduler/pkg/framework/plugins/removeduplicates"
 	"sigs.k8s.io/descheduler/pkg/framework/plugins/removepodsviolatingnodetaints"
+	frameworktypes "sigs.k8s.io/descheduler/pkg/framework/types"
 	"sigs.k8s.io/descheduler/pkg/utils"
 	deschedulerversion "sigs.k8s.io/descheduler/pkg/version"
 	"sigs.k8s.io/descheduler/test"
 )
 
+type mockPrometheusClient struct {
+	name string
+}
+
+func (m *mockPrometheusClient) URL(ep string, args map[string]string) *url.URL {
+	return nil
+}
+
+func (m *mockPrometheusClient) Do(ctx context.Context, req *http.Request) (*http.Response, []byte, error) {
+	return nil, nil, nil
+}
+
+var _ promapi.Client = &mockPrometheusClient{}
+
 var (
 	podEvictionError     = errors.New("PodEvictionError")
 	tooManyRequestsError = &apierrors.StatusError{
@@ -177,7 +200,7 @@ func lowNodeUtilizationPolicy(thresholds, targetThresholds api.ResourceThreshold
 	}
 }
 
-func initDescheduler(t *testing.T, ctx context.Context, featureGates featuregate.FeatureGate, internalDeschedulerPolicy *api.DeschedulerPolicy, metricsClient metricsclient.Interface, objects ...runtime.Object) (*options.DeschedulerServer, *descheduler, *fakeclientset.Clientset) {
+func initDescheduler(t *testing.T, ctx context.Context, featureGates featuregate.FeatureGate, internalDeschedulerPolicy *api.DeschedulerPolicy, metricsClient metricsclient.Interface, dryRun bool, objects ...runtime.Object) (*options.DeschedulerServer, *descheduler, *fakeclientset.Clientset) {
 	client := fakeclientset.NewSimpleClientset(objects...)
 	eventClient := fakeclientset.NewSimpleClientset(objects...)
 
@@ -189,19 +212,73 @@ func initDescheduler(t *testing.T, ctx context.Context, featureGates featuregate
 	rs.EventClient = eventClient
 	rs.DefaultFeatureGates = featureGates
 	rs.MetricsClient = metricsClient
+	rs.DryRun = dryRun
 
 	sharedInformerFactory := informers.NewSharedInformerFactoryWithOptions(rs.Client, 0, informers.WithTransform(trimManagedFields))
 	eventBroadcaster, eventRecorder := utils.GetRecorderAndBroadcaster(ctx, client)
 
-	descheduler, err := newDescheduler(ctx, rs, internalDeschedulerPolicy, "v1", eventRecorder, sharedInformerFactory, nil)
+	// Always create descheduler with real client/factory first to register all informers
+	descheduler, err := newDescheduler(ctx, rs, internalDeschedulerPolicy, "v1", eventRecorder, rs.Client, sharedInformerFactory, nil)
 	if err != nil {
 		eventBroadcaster.Shutdown()
-		t.Fatalf("Unable to create a descheduler instance: %v", err)
+		t.Fatalf("Unable to create descheduler instance: %v", err)
 	}
 
+	// Setup Prometheus provider (only for real client case, not for dry run)
+	if err := setupPrometheusProvider(descheduler, nil); err != nil {
+		eventBroadcaster.Shutdown()
+		t.Fatalf("Failed to setup Prometheus provider: %v", err)
+	}
+
+	// If in dry run mode, replace the descheduler with one using fake client/factory
+	if dryRun {
+		// Create sandbox with resources to mirror from real client
+		kubeClientSandbox, err := newDefaultKubeClientSandbox(rs.Client, sharedInformerFactory)
+		if err != nil {
+			eventBroadcaster.Shutdown()
+			t.Fatalf("Failed to create kube client sandbox: %v", err)
+		}
+
+		// Replace descheduler with one using fake client/factory
+		descheduler, err = newDescheduler(ctx, rs, internalDeschedulerPolicy, "v1", eventRecorder, kubeClientSandbox.fakeClient(), kubeClientSandbox.fakeSharedInformerFactory(), kubeClientSandbox)
+		if err != nil {
+			eventBroadcaster.Shutdown()
+			t.Fatalf("Unable to create dry run descheduler instance: %v", err)
+		}
+	}
+
+	// Start the real shared informer factory after creating the descheduler
+	if dryRun {
+		descheduler.kubeClientSandbox.fakeSharedInformerFactory().Start(ctx.Done())
+		descheduler.kubeClientSandbox.fakeSharedInformerFactory().WaitForCacheSync(ctx.Done())
+	}
 	sharedInformerFactory.Start(ctx.Done())
 	sharedInformerFactory.WaitForCacheSync(ctx.Done())
 
+	if dryRun {
+		if err := wait.PollUntilContextTimeout(ctx, 100*time.Millisecond, 5*time.Second, true, func(ctx context.Context) (bool, error) {
+			for _, obj := range objects {
+				exists, err := descheduler.kubeClientSandbox.hasRuntimeObjectInIndexer(obj)
+				if err != nil {
+					return false, err
+				}
+				metaObj, err := meta.Accessor(obj)
+				if err != nil {
+					return false, fmt.Errorf("failed to get object metadata: %w", err)
+				}
+				key := cache.MetaObjectToName(metaObj).String()
+				if !exists {
+					klog.Infof("Object %q has not propagated to the indexer", key)
+					return false, nil
+				}
+				klog.Infof("Object %q has propagated to the indexer", key)
+			}
+			return true, nil
+		}); err != nil {
+			t.Fatalf("nodes did not propagate to the indexer: %v", err)
+		}
+	}
+
 	return rs, descheduler, client
 }
 
@@ -477,71 +554,92 @@ func taintNodeNoSchedule(node *v1.Node) {
 func TestPodEvictorReset(t *testing.T) {
 	initPluginRegistry()
 
+	tests := []struct {
+		name   string
+		dryRun bool
+		cycles []struct {
+			expectedTotalEvicted  uint
+			expectedRealEvictions int
+			expectedFakeEvictions int
+		}
+	}{
+		{
+			name:   "real mode",
+			dryRun: false,
+			cycles: []struct {
+				expectedTotalEvicted  uint
+				expectedRealEvictions int
+				expectedFakeEvictions int
+			}{
+				{expectedTotalEvicted: 2, expectedRealEvictions: 2, expectedFakeEvictions: 0},
+				{expectedTotalEvicted: 2, expectedRealEvictions: 4, expectedFakeEvictions: 0},
+			},
+		},
+		{
+			name:   "dry mode",
+			dryRun: true,
+			cycles: []struct {
+				expectedTotalEvicted  uint
+				expectedRealEvictions int
+				expectedFakeEvictions int
+			}{
+				{expectedTotalEvicted: 2, expectedRealEvictions: 0, expectedFakeEvictions: 2},
+				{expectedTotalEvicted: 2, expectedRealEvictions: 0, expectedFakeEvictions: 4},
+			},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
 			ctx := context.Background()
 			node1 := test.BuildTestNode("n1", 2000, 3000, 10, taintNodeNoSchedule)
 			node2 := test.BuildTestNode("n2", 2000, 3000, 10, nil)
-	nodes := []*v1.Node{node1, node2}
 
-	ownerRef1 := test.GetReplicaSetOwnerRefList()
-	updatePod := func(pod *v1.Pod) {
-		pod.Namespace = "dev"
-		pod.ObjectMeta.OwnerReferences = ownerRef1
-	}
-
-	p1 := test.BuildTestPod("p1", 100, 0, node1.Name, updatePod)
-	p2 := test.BuildTestPod("p2", 100, 0, node1.Name, updatePod)
+			p1 := test.BuildTestPod("p1", 100, 0, node1.Name, test.SetRSOwnerRef)
+			p2 := test.BuildTestPod("p2", 100, 0, node1.Name, test.SetRSOwnerRef)
 
 			internalDeschedulerPolicy := removePodsViolatingNodeTaintsPolicy()
 			ctxCancel, cancel := context.WithCancel(ctx)
-	rs, descheduler, client := initDescheduler(t, ctxCancel, initFeatureGates(), internalDeschedulerPolicy, nil, node1, node2, p1, p2)
+			_, descheduler, client := initDescheduler(t, ctxCancel, initFeatureGates(), internalDeschedulerPolicy, nil, tc.dryRun, node1, node2, p1, p2)
 			defer cancel()
 
 			var evictedPods []string
 			client.PrependReactor("create", "pods", podEvictionReactionTestingFnc(&evictedPods, nil, nil))
 
 			var fakeEvictedPods []string
-	descheduler.podEvictionReactionFnc = func(*fakeclientset.Clientset) func(action core.Action) (bool, runtime.Object, error) {
-		return podEvictionReactionTestingFnc(&fakeEvictedPods, nil, nil)
+			for i, cycle := range tc.cycles {
+				evictedPodNames := runDeschedulerLoopAndGetEvictedPods(ctx, t, descheduler, tc.dryRun)
+				fakeEvictedPods = append(fakeEvictedPods, evictedPodNames...)
+
+				if descheduler.podEvictor.TotalEvicted() != cycle.expectedTotalEvicted || len(evictedPods) != cycle.expectedRealEvictions || len(fakeEvictedPods) != cycle.expectedFakeEvictions {
+					t.Fatalf("Cycle %d: Expected (%v,%v,%v) pods evicted, got (%v,%v,%v) instead", i+1, cycle.expectedTotalEvicted, cycle.expectedRealEvictions, cycle.expectedFakeEvictions, descheduler.podEvictor.TotalEvicted(), len(evictedPods), len(fakeEvictedPods))
+				}
+			}
+		})
+	}
+}
+
+// runDeschedulerLoopAndGetEvictedPods runs a descheduling cycle and returns the names of evicted pods.
+// This is similar to runDeschedulerLoop but captures evicted pod names before the cache is reset.
+func runDeschedulerLoopAndGetEvictedPods(ctx context.Context, t *testing.T, d *descheduler, dryRun bool) []string {
+	d.podEvictor.ResetCounters()
+
+	d.runProfiles(ctx)
+
+	var evictedPodNames []string
+	if dryRun {
+		evictedPodsFromCache := d.kubeClientSandbox.evictedPodsCache.list()
+		for _, pod := range evictedPodsFromCache {
+			evictedPodNames = append(evictedPodNames, pod.Name)
 		}
 
-	// a single pod eviction expected
-	klog.Infof("2 pod eviction expected per a descheduling cycle, 2 real evictions in total")
-	if err := descheduler.runDeschedulerLoop(ctx, nodes); err != nil {
-		t.Fatalf("Unable to run a descheduling loop: %v", err)
+		if err := d.kubeClientSandbox.restoreEvictedPods(ctx); err != nil {
+			t.Fatalf("Failed to restore evicted pods: %v", err)
 		}
-	if descheduler.podEvictor.TotalEvicted() != 2 || len(evictedPods) != 2 || len(fakeEvictedPods) != 0 {
-		t.Fatalf("Expected (2,2,0) pods evicted, got (%v, %v, %v) instead", descheduler.podEvictor.TotalEvicted(), len(evictedPods), len(fakeEvictedPods))
+		d.kubeClientSandbox.reset()
 	}
 
-	// a single pod eviction expected
-	klog.Infof("2 pod eviction expected per a descheduling cycle, 4 real evictions in total")
-	if err := descheduler.runDeschedulerLoop(ctx, nodes); err != nil {
-		t.Fatalf("Unable to run a descheduling loop: %v", err)
-	}
-	if descheduler.podEvictor.TotalEvicted() != 2 || len(evictedPods) != 4 || len(fakeEvictedPods) != 0 {
-		t.Fatalf("Expected (2,4,0) pods evicted, got (%v, %v, %v) instead", descheduler.podEvictor.TotalEvicted(), len(evictedPods), len(fakeEvictedPods))
-	}
-
-	// check the fake client syncing and the right pods evicted
-	klog.Infof("Enabling the dry run mode")
-	rs.DryRun = true
-	evictedPods = []string{}
-
-	klog.Infof("2 pod eviction expected per a descheduling cycle, 2 fake evictions in total")
-	if err := descheduler.runDeschedulerLoop(ctx, nodes); err != nil {
-		t.Fatalf("Unable to run a descheduling loop: %v", err)
-	}
-	if descheduler.podEvictor.TotalEvicted() != 2 || len(evictedPods) != 0 || len(fakeEvictedPods) != 2 {
-		t.Fatalf("Expected (2,0,2) pods evicted, got (%v, %v, %v) instead", descheduler.podEvictor.TotalEvicted(), len(evictedPods), len(fakeEvictedPods))
-	}
-
-	klog.Infof("2 pod eviction expected per a descheduling cycle, 4 fake evictions in total")
-	if err := descheduler.runDeschedulerLoop(ctx, nodes); err != nil {
-		t.Fatalf("Unable to run a descheduling loop: %v", err)
-	}
-	if descheduler.podEvictor.TotalEvicted() != 2 || len(evictedPods) != 0 || len(fakeEvictedPods) != 4 {
-		t.Fatalf("Expected (2,0,4) pods evicted, got (%v, %v, %v) instead", descheduler.podEvictor.TotalEvicted(), len(evictedPods), len(fakeEvictedPods))
-	}
+	return evictedPodNames
 }
 
 func checkTotals(t *testing.T, ctx context.Context, descheduler *descheduler, totalEvictionRequests, totalEvicted uint) {
@@ -555,7 +653,7 @@ func checkTotals(t *testing.T, ctx context.Context, descheduler *descheduler, to
 }
 
 func runDeschedulingCycleAndCheckTotals(t *testing.T, ctx context.Context, nodes []*v1.Node, descheduler *descheduler, totalEvictionRequests, totalEvicted uint) {
-	err := descheduler.runDeschedulerLoop(ctx, nodes)
+	err := descheduler.runDeschedulerLoop(ctx)
 	if err != nil {
 		t.Fatalf("Unable to run a descheduling loop: %v", err)
 	}
@@ -595,14 +693,9 @@ func TestEvictionRequestsCache(t *testing.T) {
 	featureGates.Add(map[featuregate.Feature]featuregate.FeatureSpec{
 		features.EvictionsInBackground: {Default: true, PreRelease: featuregate.Alpha},
 	})
-	_, descheduler, client := initDescheduler(t, ctxCancel, featureGates, internalDeschedulerPolicy, nil, node1, node2, p1, p2, p3, p4)
+	_, descheduler, client := initDescheduler(t, ctxCancel, featureGates, internalDeschedulerPolicy, nil, false, node1, node2, p1, p2, p3, p4)
 	defer cancel()
 
-	var fakeEvictedPods []string
-	descheduler.podEvictionReactionFnc = func(*fakeclientset.Clientset) func(action core.Action) (bool, runtime.Object, error) {
-		return podEvictionReactionTestingFnc(&fakeEvictedPods, nil, podEvictionError)
-	}
-
 	var evictedPods []string
 	client.PrependReactor("create", "pods", podEvictionReactionTestingFnc(&evictedPods, func(name string) bool { return name == "p1" || name == "p2" }, nil))
 
@@ -731,20 +824,14 @@ func TestDeschedulingLimits(t *testing.T) {
 			ctx := context.Background()
 			node1 := test.BuildTestNode("n1", 2000, 3000, 10, taintNodeNoSchedule)
 			node2 := test.BuildTestNode("n2", 2000, 3000, 10, nil)
-			nodes := []*v1.Node{node1, node2}
 			ctxCancel, cancel := context.WithCancel(ctx)
 			featureGates := featuregate.NewFeatureGate()
 			featureGates.Add(map[featuregate.Feature]featuregate.FeatureSpec{
 				features.EvictionsInBackground: {Default: true, PreRelease: featuregate.Alpha},
 			})
-			_, descheduler, client := initDescheduler(t, ctxCancel, featureGates, tc.policy, nil, node1, node2)
+			_, descheduler, client := initDescheduler(t, ctxCancel, featureGates, tc.policy, nil, false, node1, node2)
 			defer cancel()
 
-			var fakeEvictedPods []string
-			descheduler.podEvictionReactionFnc = func(*fakeclientset.Clientset) func(action core.Action) (bool, runtime.Object, error) {
-				return podEvictionReactionTestingFnc(&fakeEvictedPods, nil, podEvictionError)
-			}
-
 			var evictedPods []string
 			client.PrependReactor("create", "pods", podEvictionReactionTestingFnc(&evictedPods, func(name string) bool { return name == "p1" || name == "p2" }, nil))
 
@@ -774,7 +861,7 @@ func TestDeschedulingLimits(t *testing.T) {
 					time.Sleep(100 * time.Millisecond)
 
 					klog.Infof("2 evictions in background expected, 2 normal evictions")
-					err := descheduler.runDeschedulerLoop(ctx, nodes)
+					err := descheduler.runDeschedulerLoop(ctx)
 					if err != nil {
 						t.Fatalf("Unable to run a descheduling loop: %v", err)
 					}
@@ -790,6 +877,217 @@ func TestDeschedulingLimits(t *testing.T) {
 	}
 }
 
+func TestNodeLabelSelectorBasedEviction(t *testing.T) {
+	initPluginRegistry()
+
+	// createNodes creates 4 nodes with different labels and applies a taint to all of them
+	createNodes := func() (*v1.Node, *v1.Node, *v1.Node, *v1.Node) {
+		taint := []v1.Taint{
+			{
+				Key:    "test-taint",
+				Value:  "test-value",
+				Effect: v1.TaintEffectNoSchedule,
+			},
+		}
+		node1 := test.BuildTestNode("n1", 2000, 3000, 10, func(node *v1.Node) {
+			node.Labels = map[string]string{
+				"zone":        "us-east-1a",
+				"node-type":   "compute",
+				"environment": "production",
+			}
+			node.Spec.Taints = taint
+		})
+		node2 := test.BuildTestNode("n2", 2000, 3000, 10, func(node *v1.Node) {
+			node.Labels = map[string]string{
+				"zone":        "us-east-1b",
+				"node-type":   "compute",
+				"environment": "production",
+			}
+			node.Spec.Taints = taint
+		})
+		node3 := test.BuildTestNode("n3", 2000, 3000, 10, func(node *v1.Node) {
+			node.Labels = map[string]string{
+				"zone":        "us-west-1a",
+				"node-type":   "storage",
+				"environment": "staging",
+			}
+			node.Spec.Taints = taint
+		})
+		node4 := test.BuildTestNode("n4", 2000, 3000, 10, func(node *v1.Node) {
+			node.Labels = map[string]string{
+				"zone":        "us-west-1b",
+				"node-type":   "storage",
+				"environment": "staging",
+			}
+			node.Spec.Taints = taint
+		})
+		return node1, node2, node3, node4
+	}
+
+	tests := []struct {
+		description              string
+		nodeSelector             string
+		dryRun                   bool
+		expectedEvictedFromNodes []string
+	}{
+		{
+			description:              "Evict from n1, n2",
+			nodeSelector:             "environment=production",
+			dryRun:                   false,
+			expectedEvictedFromNodes: []string{"n1", "n2"},
+		},
+		{
+			description:              "Evict from n1, n2 in dry run mode",
+			nodeSelector:             "environment=production",
+			dryRun:                   true,
+			expectedEvictedFromNodes: []string{"n1", "n2"},
+		},
+		{
+			description:              "Evict from n3, n4",
+			nodeSelector:             "environment=staging",
+			dryRun:                   false,
+			expectedEvictedFromNodes: []string{"n3", "n4"},
+		},
+		{
+			description:              "Evict from n3, n4 in dry run mode",
+			nodeSelector:             "environment=staging",
+			dryRun:                   true,
+			expectedEvictedFromNodes: []string{"n3", "n4"},
+		},
+		{
+			description:              "Evict from n1, n4",
+			nodeSelector:             "zone in (us-east-1a, us-west-1b)",
+			dryRun:                   false,
+			expectedEvictedFromNodes: []string{"n1", "n4"},
+		},
+		{
+			description:              "Evict from n1, n4 in dry run mode",
+			nodeSelector:             "zone in (us-east-1a, us-west-1b)",
+			dryRun:                   true,
+			expectedEvictedFromNodes: []string{"n1", "n4"},
+		},
+		{
+			description:              "Evict from n2, n3",
+			nodeSelector:             "zone in (us-east-1b, us-west-1a)",
+			dryRun:                   false,
+			expectedEvictedFromNodes: []string{"n2", "n3"},
+		},
+		{
+			description:              "Evict from n2, n3 in dry run mode",
+			nodeSelector:             "zone in (us-east-1b, us-west-1a)",
+			dryRun:                   true,
+			expectedEvictedFromNodes: []string{"n2", "n3"},
+		},
+		{
+			description:              "Evict from all nodes",
+			nodeSelector:             "",
+			dryRun:                   false,
+			expectedEvictedFromNodes: []string{"n1", "n2", "n3", "n4"},
+		},
+		{
+			description:              "Evict from all nodes in dry run mode",
+			nodeSelector:             "",
+			dryRun:                   true,
+			expectedEvictedFromNodes: []string{"n1", "n2", "n3", "n4"},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.description, func(t *testing.T) {
+			ctx := context.Background()
+
+			// Create nodes with different labels and taints
+			node1, node2, node3, node4 := createNodes()
+
+			ownerRef := test.GetReplicaSetOwnerRefList()
+			updatePod := func(pod *v1.Pod) {
+				pod.ObjectMeta.OwnerReferences = ownerRef
+				pod.Status.Phase = v1.PodRunning
+			}
+
+			// Create one pod per node
+			p1 := test.BuildTestPod("p1", 200, 0, node1.Name, updatePod)
+			p2 := test.BuildTestPod("p2", 200, 0, node2.Name, updatePod)
+			p3 := test.BuildTestPod("p3", 200, 0, node3.Name, updatePod)
+			p4 := test.BuildTestPod("p4", 200, 0, node4.Name, updatePod)
+
+			objects := []runtime.Object{node1, node2, node3, node4, p1, p2, p3, p4}
+
+			// Map pod names to their node names for validation
+			podToNode := map[string]string{
+				"p1": "n1",
+				"p2": "n2",
+				"p3": "n3",
+				"p4": "n4",
+			}
+
+			policy := removePodsViolatingNodeTaintsPolicy()
+			if tc.nodeSelector != "" {
+				policy.NodeSelector = &tc.nodeSelector
+			}
+
+			ctxCancel, cancel := context.WithCancel(ctx)
+			_, deschedulerInstance, client := initDescheduler(t, ctxCancel, initFeatureGates(), policy, nil, tc.dryRun, objects...)
+			defer cancel()
+
+			// Verify all pods are created initially
+			pods, err := client.CoreV1().Pods(p1.Namespace).List(ctx, metav1.ListOptions{})
+			if err != nil {
+				t.Fatalf("Unable to list pods: %v", err)
+			}
+			if len(pods.Items) != 4 {
+				t.Errorf("Expected 4 pods initially, got %d", len(pods.Items))
+			}
+
+			var evictedPods []string
+			if !tc.dryRun {
+				client.PrependReactor("create", "pods", podEvictionReactionTestingFnc(&evictedPods, nil, nil))
+			}
+
+			evictedPodNames := runDeschedulerLoopAndGetEvictedPods(ctx, t, deschedulerInstance, tc.dryRun)
+			if tc.dryRun {
+				evictedPods = evictedPodNames
+			}
+
+			// Collect which nodes had pods evicted from them
+			nodesWithEvictedPods := make(map[string]bool)
+			for _, podName := range evictedPods {
+				if nodeName, ok := podToNode[podName]; ok {
+					nodesWithEvictedPods[nodeName] = true
+				}
+			}
+
+			// Verify the correct number of nodes had pods evicted
+			if len(nodesWithEvictedPods) != len(tc.expectedEvictedFromNodes) {
+				t.Fatalf("Expected pods to be evicted from %d nodes, got %d nodes: %v", len(tc.expectedEvictedFromNodes), len(nodesWithEvictedPods), nodesWithEvictedPods)
+			}
+
+			// Verify pods were evicted from the correct nodes
+			for _, nodeName := range tc.expectedEvictedFromNodes {
+				if !nodesWithEvictedPods[nodeName] {
+					t.Fatalf("Expected pod to be evicted from node %s, but it was not", nodeName)
+				}
+			}
+
+			// Verify no unexpected nodes had pods evicted
+			for nodeName := range nodesWithEvictedPods {
+				found := false
+				for _, expectedNode := range tc.expectedEvictedFromNodes {
+					if nodeName == expectedNode {
+						found = true
+						break
+					}
+				}
+				if !found {
+					t.Fatalf("Unexpected eviction from node %s", nodeName)
+				}
+			}
+
+			t.Logf("Successfully evicted pods from nodes: %v", tc.expectedEvictedFromNodes)
+		})
+	}
+}
+
 func TestLoadAwareDescheduling(t *testing.T) {
 	initPluginRegistry()
 
@@ -801,7 +1099,6 @@ func TestLoadAwareDescheduling(t *testing.T) {
 	ctx := context.Background()
 	node1 := test.BuildTestNode("n1", 2000, 3000, 10, taintNodeNoSchedule)
 	node2 := test.BuildTestNode("n2", 2000, 3000, 10, nil)
-	nodes := []*v1.Node{node1, node2}
 
 	p1 := test.BuildTestPod("p1", 300, 0, node1.Name, updatePod)
 	p2 := test.BuildTestPod("p2", 300, 0, node1.Name, updatePod)
@@ -850,6 +1147,7 @@ func TestLoadAwareDescheduling(t *testing.T) {
 		initFeatureGates(),
 		policy,
 		metricsClientset,
+		false,
 		node1, node2, p1, p2, p3, p4, p5)
 	defer cancel()
 
@@ -857,7 +1155,7 @@ func TestLoadAwareDescheduling(t *testing.T) {
 	// after newDescheduler in RunDeschedulerStrategies.
 	descheduler.metricsCollector.Collect(ctx)
 
-	err := descheduler.runDeschedulerLoop(ctx, nodes)
+	err := descheduler.runDeschedulerLoop(ctx)
 	if err != nil {
 		t.Fatalf("Unable to run a descheduling loop: %v", err)
 	}
@@ -867,3 +1165,407 @@ func TestLoadAwareDescheduling(t *testing.T) {
 	}
 	t.Logf("Total evictions: %v", totalEs)
 }
+
+func TestPodEvictionReactionFncErrorHandling(t *testing.T) {
+	podsGVR := schema.GroupVersionResource{Group: "", Version: "v1", Resource: "pods"}
+
+	testCases := []struct {
+		name             string
+		setupFnc         func(*fakeclientset.Clientset) (name, namespace string)
+		expectHandled    bool
+		expectError      bool
+		errorContains    string
+		expectedCacheLen int
+	}{
+		{
+			name: "handles pod eviction successfully and adds to cache",
+			setupFnc: func(fakeClient *fakeclientset.Clientset) (string, string) {
+				pod := test.BuildTestPod("pod1", 100, 0, "node1", test.SetRSOwnerRef)
+				err := fakeClient.Tracker().Add(pod)
+				if err != nil {
+					t.Fatalf("Failed to add pod: %v", err)
+				}
+				return pod.Name, pod.Namespace
+			},
+			expectHandled:    true,
+			expectError:      false,
+			expectedCacheLen: 1,
+		},
+		{
+			name: "returns false and error when delete fails allowing other reactors to handle",
+			setupFnc: func(fakeClient *fakeclientset.Clientset) (string, string) {
+				pod := test.BuildTestPod("pod1", 100, 0, "node1", test.SetRSOwnerRef)
+				if err := fakeClient.Tracker().Add(pod); err != nil {
+					t.Fatalf("Failed to add pod: %v", err)
+				}
+				if err := fakeClient.Tracker().Delete(podsGVR, pod.Namespace, pod.Name); err != nil {
+					t.Fatalf("Failed to pre-delete pod: %v", err)
+				}
+				return pod.Name, pod.Namespace
+			},
+			expectHandled:    false,
+			expectError:      true,
+			errorContains:    "unable to delete pod",
+			expectedCacheLen: 0,
+		},
+		{
+			name: "returns error when pod doesn't exist in tracker from the start",
+			setupFnc: func(fakeClient *fakeclientset.Clientset) (string, string) {
+				// Don't add the pod to the tracker at all
+				return "nonexistent-pod", "default"
+			},
+			expectHandled:    false,
+			expectError:      true,
+			errorContains:    "unable to delete pod",
+			expectedCacheLen: 0,
+		},
+		{
+			name: "returns error when object is not a pod",
+			setupFnc: func(fakeClient *fakeclientset.Clientset) (string, string) {
+				configMap := &v1.ConfigMap{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      "test-config",
+						Namespace: "default",
+					},
+				}
+				if err := fakeClient.Tracker().Create(podsGVR, configMap, "default"); err != nil {
+					t.Fatalf("Failed to add ConfigMap to pods resource: %v", err)
+				}
+				return configMap.Name, configMap.Namespace
+			},
+			expectHandled:    false,
+			expectError:      true,
+			errorContains:    "unable to convert object to *v1.Pod",
+			expectedCacheLen: 0,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			fakeClient := fakeclientset.NewSimpleClientset()
+			cache := newEvictedPodsCache()
+
+			name, namespace := tc.setupFnc(fakeClient)
+
+			reactionFnc := podEvictionReactionFnc(fakeClient, cache)
+
+			handled, _, err := reactionFnc(core.NewCreateSubresourceAction(
+				podsGVR,
+				name,
+				"eviction",
+				namespace,
+				&policy.Eviction{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      name,
+						Namespace: namespace,
+					},
+				},
+			))
+
+			if handled != tc.expectHandled {
+				t.Errorf("Expected handled=%v, got %v", tc.expectHandled, handled)
+			}
+
+			if tc.expectError {
+				if err == nil {
+					t.Fatal("Expected error, got nil")
+				}
+				if !strings.Contains(err.Error(), tc.errorContains) {
+					t.Errorf("Expected error message to contain '%s', got: %v", tc.errorContains, err)
+				}
+			} else {
+				if err != nil {
+					t.Errorf("Expected no error, got: %v", err)
+				}
+			}
+
+			if len(cache.list()) != tc.expectedCacheLen {
+				t.Errorf("Expected %d pods in cache, got %d", tc.expectedCacheLen, len(cache.list()))
+			}
+		})
+	}
+}
+
+// verifyPodIdentityFields checks if name, namespace, and UID match expected values
+func verifyPodIdentityFields(t *testing.T, name, namespace, uid, expectedName, expectedNamespace, expectedUID, context string) {
+	t.Helper()
+	if name != expectedName {
+		t.Fatalf("Expected pod name %s%s, got %s", expectedName, context, name)
+	}
+	if namespace != expectedNamespace {
+		t.Fatalf("Expected pod namespace %s%s, got %s", expectedNamespace, context, namespace)
+	}
+	if uid != expectedUID {
+		t.Fatalf("Expected pod UID %s%s, got %s", expectedUID, context, uid)
+	}
+}
+
+// verifyPodIdentity checks if a pod has the expected name, namespace, and UID
+func verifyPodIdentity(t *testing.T, pod *v1.Pod, expectedName, expectedNamespace string, expectedUID types.UID) {
+	t.Helper()
+	verifyPodIdentityFields(t, pod.Name, pod.Namespace, string(pod.UID), expectedName, expectedNamespace, string(expectedUID), "")
+}
+
+func TestEvictedPodRestorationInDryRun(t *testing.T) {
+	// Initialize klog flags
+	// klog.InitFlags(nil)
+
+	// Set verbosity level (higher number = more verbose)
+	// 0 = errors only, 1-4 = info, 5-9 = debug, 10+ = trace
+	// flag.Set("v", "4")
+
+	initPluginRegistry()
+
+	ctx := context.Background()
+	node1 := test.BuildTestNode("n1", 2000, 3000, 10, taintNodeNoSchedule)
+	node2 := test.BuildTestNode("n2", 2000, 3000, 10, nil)
+
+	p1 := test.BuildTestPod("p1", 100, 0, node1.Name, test.SetRSOwnerRef)
+
+	internalDeschedulerPolicy := removePodsViolatingNodeTaintsPolicy()
+	ctxCancel, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	// Create descheduler with DryRun mode
+	client := fakeclientset.NewSimpleClientset(node1, node2, p1)
+	eventClient := fakeclientset.NewSimpleClientset(node1, node2, p1)
+
+	rs, err := options.NewDeschedulerServer()
+	if err != nil {
+		t.Fatalf("Unable to initialize server: %v", err)
+	}
+	rs.Client = client
+	rs.EventClient = eventClient
+	rs.DefaultFeatureGates = initFeatureGates()
+	rs.DryRun = true // Set DryRun before creating descheduler
+
+	sharedInformerFactory := informers.NewSharedInformerFactoryWithOptions(rs.Client, 0, informers.WithTransform(trimManagedFields))
+	eventBroadcaster, eventRecorder := utils.GetRecorderAndBroadcaster(ctxCancel, client)
+	defer eventBroadcaster.Shutdown()
+
+	// Always create descheduler with real client/factory first to register all informers
+	descheduler, err := newDescheduler(ctxCancel, rs, internalDeschedulerPolicy, "v1", eventRecorder, rs.Client, sharedInformerFactory, nil)
+	if err != nil {
+		t.Fatalf("Unable to create descheduler instance: %v", err)
+	}
+
+	sharedInformerFactory.Start(ctxCancel.Done())
+	sharedInformerFactory.WaitForCacheSync(ctxCancel.Done())
+
+	// Create sandbox with resources to mirror from real client
+	kubeClientSandbox, err := newDefaultKubeClientSandbox(rs.Client, sharedInformerFactory)
+	if err != nil {
+		t.Fatalf("Failed to create kube client sandbox: %v", err)
+	}
+
+	// Replace descheduler with one using fake client/factory
+	descheduler, err = newDescheduler(ctxCancel, rs, internalDeschedulerPolicy, "v1", eventRecorder, kubeClientSandbox.fakeClient(), kubeClientSandbox.fakeSharedInformerFactory(), kubeClientSandbox)
+	if err != nil {
+		t.Fatalf("Unable to create dry run descheduler instance: %v", err)
+	}
+
+	// Start and sync the fake factory after creating the descheduler
+	kubeClientSandbox.fakeSharedInformerFactory().Start(ctxCancel.Done())
+	kubeClientSandbox.fakeSharedInformerFactory().WaitForCacheSync(ctxCancel.Done())
+
+	// Verify the pod exists in the fake client after initialization
+	pod, err := kubeClientSandbox.fakeClient().CoreV1().Pods(p1.Namespace).Get(ctx, p1.Name, metav1.GetOptions{})
+	if err != nil {
+		t.Fatalf("Expected pod %s to exist in fake client after initialization, but got error: %v", p1.Name, err)
+	}
+	verifyPodIdentity(t, pod, p1.Name, p1.Namespace, p1.UID)
+	klog.Infof("Pod %s exists in fake client after initialization", p1.Name)
+
+	// Run two descheduling cycles to verify pod eviction and restoration works repeatedly
+	for i := 1; i <= 2; i++ {
+		// Run descheduling cycle
+		klog.Infof("Running descheduling cycle %d", i)
+		descheduler.podEvictor.ResetCounters()
+		descheduler.runProfiles(ctx)
+
+		// Verify the pod was evicted (should not exist in fake client anymore)
+		_, err = kubeClientSandbox.fakeClient().CoreV1().Pods(p1.Namespace).Get(ctx, p1.Name, metav1.GetOptions{})
+		if err == nil {
+			t.Fatalf("Expected pod %s to be evicted from fake client in cycle %d, but it still exists", p1.Name, i)
+		}
+		if !apierrors.IsNotFound(err) {
+			t.Fatalf("Expected NotFound error for pod %s in cycle %d, got: %v", p1.Name, i, err)
+		}
+		klog.Infof("Pod %s was successfully evicted from fake client in cycle %d", p1.Name, i)
+
+		// Verify the pod was added to the evicted pods cache
+		evictedPods := descheduler.kubeClientSandbox.evictedPodsCache.list()
+		if len(evictedPods) != 1 {
+			t.Fatalf("Expected 1 pod in evicted cache in cycle %d, got %d", i, len(evictedPods))
+		}
+		verifyPodIdentityFields(t, evictedPods[0].Name, evictedPods[0].Namespace, evictedPods[0].UID, p1.Name, p1.Namespace, string(p1.UID), fmt.Sprintf(" in cycle %d", i))
+		klog.Infof("Pod %s was successfully added to evicted pods cache in cycle %d (UID: %s)", p1.Name, i, p1.UID)
+
+		// Restore evicted pods
+		klog.Infof("Restoring evicted pods from cache in cycle %d", i)
+		if err := descheduler.kubeClientSandbox.restoreEvictedPods(ctx); err != nil {
+			t.Fatalf("Failed to restore evicted pods in cycle %d: %v", i, err)
+		}
+		descheduler.kubeClientSandbox.evictedPodsCache.clear()
+
+		// Verify the pod was restored back to the fake client
+		pod, err = kubeClientSandbox.fakeClient().CoreV1().Pods(p1.Namespace).Get(ctx, p1.Name, metav1.GetOptions{})
+		if err != nil {
+			t.Fatalf("Expected pod %s to be restored to fake client in cycle %d, but got error: %v", p1.Name, i, err)
+		}
+		verifyPodIdentity(t, pod, p1.Name, p1.Namespace, p1.UID)
+		klog.Infof("Pod %s was successfully restored to fake client in cycle %d (UID: %s)", p1.Name, i, pod.UID)
+
+		// Verify cache was cleared after restoration
+		evictedPods = descheduler.kubeClientSandbox.evictedPodsCache.list()
+		if len(evictedPods) != 0 {
+			t.Fatalf("Expected evicted cache to be empty after restoration in cycle %d, got %d pods", i, len(evictedPods))
+		}
+		klog.Infof("Evicted pods cache was cleared after restoration in cycle %d", i)
+	}
+}
+
+// verifyAllPrometheusClientsEqual checks that all Prometheus client variables are equal to the expected value
+func verifyAllPrometheusClientsEqual(t *testing.T, expected, fromReactor, fromPluginHandle, fromDescheduler promapi.Client) {
+	t.Helper()
+	if fromReactor != expected {
+		t.Fatalf("Prometheus client from reactor: expected %v, got %v", expected, fromReactor)
+	}
+	if fromPluginHandle != expected {
+		t.Fatalf("Prometheus client from plugin handle: expected %v, got %v", expected, fromPluginHandle)
+	}
+	if fromDescheduler != expected {
+		t.Fatalf("Prometheus client from descheduler: expected %v, got %v", expected, fromDescheduler)
+	}
+	t.Logf("All Prometheus clients variables correctly set to: %v", expected)
+}
+
+// TestPluginPrometheusClientAccess tests that the Prometheus client is accessible through the plugin handle
+func TestPluginPrometheusClientAccess(t *testing.T) {
+	testCases := []struct {
+		name   string
+		dryRun bool
+	}{
+		{
+			name:   "dry run disabled",
+			dryRun: false,
+		},
+		{
+			name:   "dry run enabled",
+			dryRun: true,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			ctx := context.Background()
+
+			initPluginRegistry()
+
+			newInvoked := false
+			reactorInvoked := false
+			var prometheusClientFromPluginNewHandle promapi.Client
+			var prometheusClientFromReactor promapi.Client
+
+			fakePlugin := &fakeplugin.FakePlugin{
+				PluginName: "TestPluginWithPrometheusClient",
+			}
+
+			fakePlugin.AddReactor(string(frameworktypes.DescheduleExtensionPoint), func(action fakeplugin.Action) (handled, filter bool, err error) {
+				if dAction, ok := action.(fakeplugin.DescheduleAction); ok {
+					reactorInvoked = true
+					prometheusClientFromReactor = dAction.Handle().PrometheusClient()
+					return true, false, nil
+				}
+				return false, false, nil
+			})
+
+			pluginregistry.Register(
+				fakePlugin.PluginName,
+				fakeplugin.NewPluginFncFromFakeWithReactor(fakePlugin, func(action fakeplugin.ActionImpl) {
+					newInvoked = true
+					prometheusClientFromPluginNewHandle = action.Handle().PrometheusClient()
+				}),
+				&fakeplugin.FakePlugin{},
+				&fakeplugin.FakePluginArgs{},
+				fakeplugin.ValidateFakePluginArgs,
+				fakeplugin.SetDefaults_FakePluginArgs,
+				pluginregistry.PluginRegistry,
+			)
+
+			deschedulerPolicy := &api.DeschedulerPolicy{
+				Profiles: []api.DeschedulerProfile{
+					{
+						Name: "test-profile",
+						PluginConfigs: []api.PluginConfig{
+							{
+								Name: fakePlugin.PluginName,
+								Args: &fakeplugin.FakePluginArgs{},
+							},
+						},
+						Plugins: api.Plugins{
+							Deschedule: api.PluginSet{
+								Enabled: []string{fakePlugin.PluginName},
+							},
+						},
+					},
+				},
+			}
+
+			node1 := test.BuildTestNode("node1", 1000, 2000, 9, nil)
+			node2 := test.BuildTestNode("node2", 1000, 2000, 9, nil)
+
+			_, descheduler, _ := initDescheduler(t, ctx, initFeatureGates(), deschedulerPolicy, nil, tc.dryRun, node1, node2)
+
+			// Test cycles with different Prometheus client values
+			cycles := []struct {
+				name   string
+				client promapi.Client
+			}{
+				{
+					name:   "initial client",
+					client: &mockPrometheusClient{name: "new-init-client"},
+				},
+				{
+					name:   "nil client",
+					client: nil,
+				},
+				{
+					name:   "new client",
+					client: &mockPrometheusClient{name: "new-client"},
+				},
+				{
+					name:   "another client",
+					client: &mockPrometheusClient{name: "another-client"},
+				},
+			}
+
+			for i, cycle := range cycles {
+				t.Logf("Cycle %d: %s", i+1, cycle.name)
+
+				// Set the descheduler's Prometheus client
+				t.Logf("Setting descheduler.prometheusClient from %v to %v", descheduler.prometheusClient, cycle.client)
+				descheduler.prometheusClient = cycle.client
+
+				newInvoked = false
+				reactorInvoked = false
+				prometheusClientFromPluginNewHandle = nil
+				prometheusClientFromReactor = nil
+
+				descheduler.runProfiles(ctx)
+
+				t.Logf("After cycle %d: prometheusClientFromReactor=%v, descheduler.prometheusClient=%v", i+1, prometheusClientFromReactor, descheduler.prometheusClient)
+
+				if !newInvoked {
+					t.Fatalf("Expected plugin new to be invoked during cycle %d", i+1)
+				}
+
+				if !reactorInvoked {
+					t.Fatalf("Expected deschedule reactor to be invoked during cycle %d", i+1)
+				}
+
+				verifyAllPrometheusClientsEqual(t, cycle.client, prometheusClientFromReactor, prometheusClientFromPluginNewHandle, descheduler.prometheusClient)
+			}
+		})
+	}
+}

pkg/descheduler/evictions/evictions.go

@@ -403,12 +403,6 @@ func (pe *PodEvictor) ResetCounters() {
 	pe.totalPodCount = 0
 }
 
-func (pe *PodEvictor) SetClient(client clientset.Interface) {
-	pe.mu.Lock()
-	defer pe.mu.Unlock()
-	pe.client = client
-}
-
 func (pe *PodEvictor) evictionRequestsTotal() uint {
 	if pe.featureGates.Enabled(features.EvictionsInBackground) {
 		return pe.erCache.evictionRequestsTotal()

pkg/descheduler/kubeclientsandbox.go

@@ -0,0 +1,446 @@
+/*
+Copyright 2026 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package descheduler
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	v1 "k8s.io/api/core/v1"
+	policy "k8s.io/api/policy/v1"
+	policyv1 "k8s.io/api/policy/v1"
+	schedulingv1 "k8s.io/api/scheduling/v1"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/api/meta"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/informers"
+	clientset "k8s.io/client-go/kubernetes"
+	fakeclientset "k8s.io/client-go/kubernetes/fake"
+	core "k8s.io/client-go/testing"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/klog/v2"
+)
+
+// evictedPodInfo stores identifying information about a pod that was evicted during dry-run mode
+type evictedPodInfo struct {
+	Namespace string
+	Name      string
+	UID       string
+}
+
+// evictedPodsCache is a thread-safe cache for tracking pods evicted during dry-run mode
+type evictedPodsCache struct {
+	sync.RWMutex
+	pods map[string]*evictedPodInfo
+}
+
+func newEvictedPodsCache() *evictedPodsCache {
+	return &evictedPodsCache{
+		pods: make(map[string]*evictedPodInfo),
+	}
+}
+
+func (c *evictedPodsCache) add(pod *v1.Pod) {
+	c.Lock()
+	defer c.Unlock()
+	c.pods[string(pod.UID)] = &evictedPodInfo{
+		Namespace: pod.Namespace,
+		Name:      pod.Name,
+		UID:       string(pod.UID),
+	}
+}
+
+func (c *evictedPodsCache) list() []*evictedPodInfo {
+	c.RLock()
+	defer c.RUnlock()
+	pods := make([]*evictedPodInfo, 0, len(c.pods))
+	for _, pod := range c.pods {
+		podCopy := *pod
+		pods = append(pods, &podCopy)
+	}
+	return pods
+}
+
+func (c *evictedPodsCache) clear() {
+	c.Lock()
+	defer c.Unlock()
+	c.pods = make(map[string]*evictedPodInfo)
+}
+
+// kubeClientSandbox creates a sandbox environment with a fake client and informer factory
+// that mirrors resources from a real client, useful for dry-run testing scenarios
+type kubeClientSandbox struct {
+	fakeKubeClient         *fakeclientset.Clientset
+	fakeFactory            informers.SharedInformerFactory
+	resourceToInformer     map[schema.GroupVersionResource]informers.GenericInformer
+	evictedPodsCache       *evictedPodsCache
+	podEvictionReactionFnc func(*fakeclientset.Clientset, *evictedPodsCache) func(action core.Action) (bool, runtime.Object, error)
+}
+
+func newDefaultKubeClientSandbox(client clientset.Interface, sharedInformerFactory informers.SharedInformerFactory) (*kubeClientSandbox, error) {
+	return newKubeClientSandbox(client, sharedInformerFactory,
+		v1.SchemeGroupVersion.WithResource("pods"),
+		v1.SchemeGroupVersion.WithResource("nodes"),
+		v1.SchemeGroupVersion.WithResource("namespaces"),
+		schedulingv1.SchemeGroupVersion.WithResource("priorityclasses"),
+		policyv1.SchemeGroupVersion.WithResource("poddisruptionbudgets"),
+		v1.SchemeGroupVersion.WithResource("persistentvolumeclaims"),
+	)
+}
+
+func newKubeClientSandbox(client clientset.Interface, sharedInformerFactory informers.SharedInformerFactory, resources ...schema.GroupVersionResource) (*kubeClientSandbox, error) {
+	sandbox := &kubeClientSandbox{
+		resourceToInformer:     make(map[schema.GroupVersionResource]informers.GenericInformer),
+		evictedPodsCache:       newEvictedPodsCache(),
+		podEvictionReactionFnc: podEvictionReactionFnc,
+	}
+
+	sandbox.fakeKubeClient = fakeclientset.NewSimpleClientset()
+	// simulate a pod eviction by deleting a pod
+	sandbox.fakeKubeClient.PrependReactor("create", "pods", sandbox.podEvictionReactionFnc(sandbox.fakeKubeClient, sandbox.evictedPodsCache))
+	sandbox.fakeFactory = informers.NewSharedInformerFactory(sandbox.fakeKubeClient, 0)
+
+	for _, resource := range resources {
+		informer, err := sharedInformerFactory.ForResource(resource)
+		if err != nil {
+			return nil, err
+		}
+		sandbox.resourceToInformer[resource] = informer
+	}
+
+	// Register event handlers to sync changes from real client to fake client.
+	// These handlers will keep the fake client in sync with ongoing changes.
+	if err := sandbox.registerEventHandlers(); err != nil {
+		return nil, fmt.Errorf("error registering event handlers: %w", err)
+	}
+
+	return sandbox, nil
+}
+
+func (sandbox *kubeClientSandbox) registerEventHandlers() error {
+	for resource, informer := range sandbox.resourceToInformer {
+		// Create a local copy to avoid closure capture issue
+		resource := resource
+
+		_, err := sandbox.fakeFactory.ForResource(resource)
+		if err != nil {
+			return fmt.Errorf("error getting resource %s for fake factory: %w", resource, err)
+		}
+
+		_, err = informer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
+			AddFunc: func(obj interface{}) {
+				runtimeObj, ok := obj.(runtime.Object)
+				if !ok {
+					klog.ErrorS(nil, "object is not a runtime.Object", "resource", resource)
+					return
+				}
+				if err := sandbox.fakeKubeClient.Tracker().Add(runtimeObj); err != nil {
+					if !apierrors.IsAlreadyExists(err) {
+						klog.ErrorS(err, "failed to add object to fake client", "resource", resource)
+					}
+				}
+			},
+			UpdateFunc: func(oldObj, newObj interface{}) {
+				runtimeObj, ok := newObj.(runtime.Object)
+				if !ok {
+					klog.ErrorS(nil, "object is not a runtime.Object", "resource", resource)
+					return
+				}
+				metaObj, err := meta.Accessor(runtimeObj)
+				if err != nil {
+					klog.ErrorS(err, "failed to get object metadata", "resource", resource)
+					return
+				}
+				if err := sandbox.fakeKubeClient.Tracker().Update(resource, runtimeObj, metaObj.GetNamespace()); err != nil {
+					klog.ErrorS(err, "failed to update object in fake client", "resource", resource)
+				}
+			},
+			DeleteFunc: func(obj interface{}) {
+				// Handle tombstone case where the object might be wrapped
+				if tombstone, ok := obj.(cache.DeletedFinalStateUnknown); ok {
+					obj = tombstone.Obj
+				}
+
+				runtimeObj, ok := obj.(runtime.Object)
+				if !ok {
+					klog.ErrorS(nil, "object is not a runtime.Object", "resource", resource)
+					return
+				}
+				metaObj, err := meta.Accessor(runtimeObj)
+				if err != nil {
+					klog.ErrorS(err, "failed to get object metadata", "resource", resource)
+					return
+				}
+				if err := sandbox.fakeKubeClient.Tracker().Delete(resource, metaObj.GetNamespace(), metaObj.GetName()); err != nil {
+					klog.ErrorS(err, "failed to delete object from fake client", "resource", resource)
+				}
+			},
+		})
+		if err != nil {
+			return fmt.Errorf("error adding event handler for resource %s: %w", resource, err)
+		}
+	}
+	return nil
+}
+
+func (sandbox *kubeClientSandbox) fakeClient() *fakeclientset.Clientset {
+	return sandbox.fakeKubeClient
+}
+
+func (sandbox *kubeClientSandbox) fakeSharedInformerFactory() informers.SharedInformerFactory {
+	return sandbox.fakeFactory
+}
+
+func (sandbox *kubeClientSandbox) reset() {
+	sandbox.evictedPodsCache.clear()
+}
+
+// hasObjectInIndexer checks if an object exists in the fake indexer for the specified resource
+func (sandbox *kubeClientSandbox) hasObjectInIndexer(resource schema.GroupVersionResource, namespace, name, uid string) (bool, error) {
+	informer, err := sandbox.fakeFactory.ForResource(resource)
+	if err != nil {
+		return false, fmt.Errorf("error getting informer for resource %s: %w", resource, err)
+	}
+
+	key := cache.MetaObjectToName(&metav1.ObjectMeta{Namespace: namespace, Name: name}).String()
+	obj, exists, err := informer.Informer().GetIndexer().GetByKey(key)
+	if err != nil {
+		return false, err
+	}
+
+	if !exists {
+		return false, nil
+	}
+
+	metaObj, err := meta.Accessor(obj)
+	if err != nil {
+		return false, fmt.Errorf("failed to get object metadata: %w", err)
+	}
+	return string(metaObj.GetUID()) == uid, nil
+}
+
+// hasRuntimeObjectInIndexer checks if a runtime.Object exists in the fake indexer by detecting its resource type
+func (sandbox *kubeClientSandbox) hasRuntimeObjectInIndexer(obj runtime.Object) (bool, error) {
+	// Get metadata accessor to extract namespace and name
+	metaObj, err := meta.Accessor(obj)
+	if err != nil {
+		return false, fmt.Errorf("failed to get object metadata: %w", err)
+	}
+
+	// Get the GVK from the object using TypeMeta
+	gvk := obj.GetObjectKind().GroupVersionKind()
+	if gvk.Empty() {
+		return false, fmt.Errorf("no GroupVersionKind found for object")
+	}
+
+	// Use the GVK to construct the GVR by pluralizing the kind
+	plural, _ := meta.UnsafeGuessKindToResource(gvk)
+	gvr := schema.GroupVersionResource{
+		Group:    gvk.Group,
+		Version:  gvk.Version,
+		Resource: plural.Resource,
+	}
+
+	return sandbox.hasObjectInIndexer(gvr, metaObj.GetNamespace(), metaObj.GetName(), string(metaObj.GetUID()))
+}
+
+// shouldSkipPodWait checks if a pod still exists in the fake client with the expected UID.
+// Returns (shouldSkip, error). shouldSkip is true if we should skip waiting for this pod.
+// Returns an error for unexpected failures (non-NotFound errors).
+func (sandbox *kubeClientSandbox) shouldSkipPodWait(ctx context.Context, pod *evictedPodInfo) (bool, error) {
+	// Check if the pod still exists in the fake client (it could have been deleted from the real client
+	// and the deletion propagated via event handlers in the meantime)
+	fakePod, err := sandbox.fakeClient().CoreV1().Pods(pod.Namespace).Get(ctx, pod.Name, metav1.GetOptions{})
+	if err != nil {
+		if apierrors.IsNotFound(err) {
+			klog.V(3).InfoS("Pod no longer exists in fake client, skipping wait", "namespace", pod.Namespace, "name", pod.Name)
+			return true, nil
+		}
+		return false, fmt.Errorf("error getting pod %s/%s from fake client: %w", pod.Namespace, pod.Name, err)
+	}
+	if string(fakePod.UID) != pod.UID {
+		klog.V(3).InfoS("Pod UID mismatch in fake client, skipping wait", "namespace", pod.Namespace, "name", pod.Name, "expectedUID", pod.UID, "actualUID", string(fakePod.UID))
+		return true, nil
+	}
+	return false, nil
+}
+
+func waitForPodsCondition(ctx context.Context, pods []*evictedPodInfo, checkFn func(*evictedPodInfo) (bool, error), successMsg string) error {
+	if len(pods) == 0 {
+		return nil
+	}
+
+	err := wait.PollUntilContextTimeout(ctx, 100*time.Millisecond, 5*time.Second, true, func(ctx context.Context) (bool, error) {
+		for _, pod := range pods {
+			satisfied, err := checkFn(pod)
+			if err != nil {
+				return false, err
+			}
+			if !satisfied {
+				return false, nil
+			}
+		}
+		return true, nil
+	})
+	if err != nil {
+		return err
+	}
+
+	klog.V(4).InfoS(successMsg)
+	return nil
+}
+
+// restoreEvictedPods restores pods from the evicted pods cache back to the fake client
+func (sandbox *kubeClientSandbox) restoreEvictedPods(ctx context.Context) error {
+	podInformer, ok := sandbox.resourceToInformer[v1.SchemeGroupVersion.WithResource("pods")]
+	if !ok {
+		return fmt.Errorf("pod informer not found in resourceToInformer")
+	}
+
+	evictedPods := sandbox.evictedPodsCache.list()
+
+	// First wait loop: Check that all evicted pods are cleared from the indexers.
+	// This ensures the eviction has fully propagated through the fake informer's indexer.
+	// We check both existence and UID match to handle cases where a pod was deleted and
+	// recreated with the same name but different UID.
+	if err := waitForPodsCondition(ctx, evictedPods, func(pod *evictedPodInfo) (bool, error) {
+		exists, err := sandbox.hasObjectInIndexer(v1.SchemeGroupVersion.WithResource("pods"), pod.Namespace, pod.Name, pod.UID)
+		if err != nil {
+			klog.V(4).InfoS("Error checking indexer for pod", "namespace", pod.Namespace, "name", pod.Name, "error", err)
+			return false, nil
+		}
+		if exists {
+			klog.V(4).InfoS("Pod with matching UID still exists in fake indexer, waiting", "namespace", pod.Namespace, "name", pod.Name, "uid", pod.UID)
+			return false, nil
+		}
+		klog.V(4).InfoS("Pod with matching UID no longer in fake indexer", "namespace", pod.Namespace, "name", pod.Name, "uid", pod.UID)
+		return true, nil
+	}, "All evicted pods removed from fake indexer"); err != nil {
+		return fmt.Errorf("timeout waiting for evicted pods to be removed from fake indexer: %w", err)
+	}
+
+	var restoredPods []*evictedPodInfo
+	for _, podInfo := range sandbox.evictedPodsCache.list() {
+		obj, err := podInformer.Lister().ByNamespace(podInfo.Namespace).Get(podInfo.Name)
+		if err != nil {
+			klog.V(3).InfoS("Pod not found in real client, skipping restoration", "namespace", podInfo.Namespace, "name", podInfo.Name, "error", err)
+			continue
+		}
+
+		pod, ok := obj.(*v1.Pod)
+		if !ok {
+			klog.ErrorS(nil, "Object is not a pod", "namespace", podInfo.Namespace, "name", podInfo.Name)
+			continue
+		}
+
+		if string(pod.UID) != podInfo.UID {
+			klog.V(3).InfoS("Pod UID mismatch, skipping restoration", "namespace", podInfo.Namespace, "name", podInfo.Name, "expectedUID", podInfo.UID, "actualUID", string(pod.UID))
+			continue
+		}
+
+		if err = sandbox.fakeKubeClient.Tracker().Add(pod); err != nil && !apierrors.IsAlreadyExists(err) {
+			return fmt.Errorf("failed to restore pod %s/%s to fake client: %w", podInfo.Namespace, podInfo.Name, err)
+		}
+		klog.V(4).InfoS("Successfully restored pod to fake client", "namespace", podInfo.Namespace, "name", podInfo.Name, "uid", podInfo.UID)
+		restoredPods = append(restoredPods, podInfo)
+	}
+
+	// Second wait loop: Make sure the evicted pods are added back to the fake client.
+	// This ensures the restored pods are accessible through the fake informer's lister.
+	if err := waitForPodsCondition(ctx, restoredPods, func(pod *evictedPodInfo) (bool, error) {
+		podObj, err := sandbox.fakeFactory.Core().V1().Pods().Lister().Pods(pod.Namespace).Get(pod.Name)
+		if err != nil {
+			klog.V(4).InfoS("Pod not yet accessible in fake informer, waiting", "namespace", pod.Namespace, "name", pod.Name)
+			shouldSkip, checkErr := sandbox.shouldSkipPodWait(ctx, pod)
+			if checkErr != nil {
+				return false, checkErr
+			}
+			if shouldSkip {
+				return true, nil
+			}
+			return false, nil
+		}
+		klog.V(4).InfoS("Pod accessible in fake informer", "namespace", pod.Namespace, "name", pod.Name, "node", podObj.Spec.NodeName)
+		return true, nil
+	}, "All restored pods are accessible in fake informer"); err != nil {
+		return fmt.Errorf("timeout waiting for pods to be accessible in fake informer: %w", err)
+	}
+
+	// Third wait loop: Make sure the indexers see the added pods.
+	// This is important to ensure each descheduling cycle can see all the restored pods.
+	// Without this wait, the next cycle might not see the restored pods in the indexer yet.
+	if err := waitForPodsCondition(ctx, restoredPods, func(pod *evictedPodInfo) (bool, error) {
+		exists, err := sandbox.hasObjectInIndexer(v1.SchemeGroupVersion.WithResource("pods"), pod.Namespace, pod.Name, pod.UID)
+		if err != nil {
+			klog.V(4).InfoS("Error checking indexer for restored pod", "namespace", pod.Namespace, "name", pod.Name, "error", err)
+			return false, nil
+		}
+		if !exists {
+			klog.V(4).InfoS("Restored pod not yet in fake indexer, waiting", "namespace", pod.Namespace, "name", pod.Name)
+			shouldSkip, checkErr := sandbox.shouldSkipPodWait(ctx, pod)
+			if checkErr != nil {
+				return false, checkErr
+			}
+			if shouldSkip {
+				return true, nil
+			}
+			return false, nil
+		}
+		klog.V(4).InfoS("Restored pod now in fake indexer", "namespace", pod.Namespace, "name", pod.Name)
+		return true, nil
+	}, "All restored pods are now in fake indexer"); err != nil {
+		return fmt.Errorf("timeout waiting for restored pods to appear in fake indexer: %w", err)
+	}
+
+	return nil
+}
+
+func podEvictionReactionFnc(fakeClient *fakeclientset.Clientset, evictedCache *evictedPodsCache) func(action core.Action) (bool, runtime.Object, error) {
+	return func(action core.Action) (bool, runtime.Object, error) {
+		if action.GetSubresource() == "eviction" {
+			createAct, matched := action.(core.CreateActionImpl)
+			if !matched {
+				return false, nil, fmt.Errorf("unable to convert action to core.CreateActionImpl")
+			}
+			eviction, matched := createAct.Object.(*policy.Eviction)
+			if !matched {
+				return false, nil, fmt.Errorf("unable to convert action object into *policy.Eviction")
+			}
+			podObj, err := fakeClient.Tracker().Get(action.GetResource(), eviction.GetNamespace(), eviction.GetName())
+			if err == nil {
+				if pod, ok := podObj.(*v1.Pod); ok {
+					evictedCache.add(pod)
+				} else {
+					return false, nil, fmt.Errorf("unable to convert object to *v1.Pod for %v/%v", eviction.GetNamespace(), eviction.GetName())
+				}
+			} else if !apierrors.IsNotFound(err) {
+				return false, nil, fmt.Errorf("unable to get pod %v/%v: %v", eviction.GetNamespace(), eviction.GetName(), err)
+			}
+			if err := fakeClient.Tracker().Delete(action.GetResource(), eviction.GetNamespace(), eviction.GetName()); err != nil {
+				return false, nil, fmt.Errorf("unable to delete pod %v/%v: %v", eviction.GetNamespace(), eviction.GetName(), err)
+			}
+			return true, nil, nil
+		}
+		// fallback to the default reactor
+		return false, nil, nil
+	}
+}

pkg/descheduler/kubeclientsandbox_test.go

@@ -0,0 +1,582 @@
+/*
+Copyright 2026 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package descheduler
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	v1 "k8s.io/api/core/v1"
+	policy "k8s.io/api/policy/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/informers"
+	clientset "k8s.io/client-go/kubernetes"
+	fakeclientset "k8s.io/client-go/kubernetes/fake"
+
+	"sigs.k8s.io/descheduler/test"
+)
+
+// setupTestSandbox creates and initializes a kubeClientSandbox for testing.
+// It creates a fake client, informer factory, registers pod and node informers,
+// creates the sandbox, and starts both factories.
+func setupTestSandbox(ctx context.Context, t *testing.T, initialObjects ...runtime.Object) (*kubeClientSandbox, informers.SharedInformerFactory, clientset.Interface) {
+	// Create a "real" fake client to act as the source of truth
+	realClient := fakeclientset.NewSimpleClientset(initialObjects...)
+	realFactory := informers.NewSharedInformerFactoryWithOptions(realClient, 0)
+
+	// Register pods and nodes informers BEFORE creating the sandbox
+	_ = realFactory.Core().V1().Pods().Informer()
+	_ = realFactory.Core().V1().Nodes().Informer()
+
+	// Create the sandbox with only pods and nodes resources
+	sandbox, err := newKubeClientSandbox(realClient, realFactory,
+		v1.SchemeGroupVersion.WithResource("pods"),
+		v1.SchemeGroupVersion.WithResource("nodes"),
+	)
+	if err != nil {
+		t.Fatalf("Failed to create kubeClientSandbox: %v", err)
+	}
+
+	// fake factory created by newKubeClientSandbox needs to be started before
+	// the "real" fake client factory to have all handlers registered
+	// to get complete propagation
+	sandbox.fakeSharedInformerFactory().Start(ctx.Done())
+	sandbox.fakeSharedInformerFactory().WaitForCacheSync(ctx.Done())
+
+	realFactory.Start(ctx.Done())
+	realFactory.WaitForCacheSync(ctx.Done())
+
+	return sandbox, realFactory, realClient
+}
+
+func TestKubeClientSandboxEventHandlers(t *testing.T) {
+	ctx := context.Background()
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	sandbox, realFactory, realClient := setupTestSandbox(ctx, t)
+
+	// Register a third resource (secrets) in the real factory AFTER sandbox creation
+	// This should NOT be synced to the fake client
+	_ = realFactory.Core().V1().Secrets().Informer()
+
+	// Create test objects
+	testPod := &v1.Pod{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "test-pod",
+			Namespace: "default",
+			UID:       "pod-uid-12345",
+		},
+		Spec: v1.PodSpec{
+			NodeName: "test-node",
+		},
+	}
+
+	testNode := &v1.Node{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: "test-node",
+			UID:  "node-uid-67890",
+		},
+	}
+
+	testSecret := &v1.Secret{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "test-secret",
+			Namespace: "default",
+			UID:       "secret-uid-abcde",
+		},
+		Data: map[string][]byte{
+			"key": []byte("value"),
+		},
+	}
+
+	// Add objects to the real client
+	var err error
+	_, err = realClient.CoreV1().Pods(testPod.Namespace).Create(ctx, testPod, metav1.CreateOptions{})
+	if err != nil {
+		t.Fatalf("Failed to create pod in real client: %v", err)
+	}
+
+	_, err = realClient.CoreV1().Nodes().Create(ctx, testNode, metav1.CreateOptions{})
+	if err != nil {
+		t.Fatalf("Failed to create node in real client: %v", err)
+	}
+
+	_, err = realClient.CoreV1().Secrets(testSecret.Namespace).Create(ctx, testSecret, metav1.CreateOptions{})
+	if err != nil {
+		t.Fatalf("Failed to create secret in real client: %v", err)
+	}
+
+	// Helper function to wait for a resource to appear in the sandbox's fake client indexer
+	waitForResourceInIndexer := func(resourceType, namespace, name, uid, description string) error {
+		t.Logf("Waiting for %s to appear in fake client indexer...", description)
+		return wait.PollUntilContextTimeout(ctx, 100*time.Millisecond, 5*time.Second, true, func(ctx context.Context) (bool, error) {
+			exists, err := sandbox.hasObjectInIndexer(
+				v1.SchemeGroupVersion.WithResource(resourceType),
+				namespace,
+				name,
+				uid,
+			)
+			if err != nil {
+				t.Logf("Error checking %s in indexer: %v", description, err)
+				return false, nil
+			}
+			if exists {
+				t.Logf("%s appeared in fake client indexer", description)
+				return true, nil
+			}
+			return false, nil
+		})
+	}
+
+	// Wait for the pod to appear in the sandbox's fake client indexer
+	if err := waitForResourceInIndexer("pods", testPod.Namespace, testPod.Name, string(testPod.UID), "pod"); err != nil {
+		t.Fatalf("Pod did not appear in fake client indexer within timeout: %v", err)
+	}
+
+	// Wait for the node to appear in the sandbox's fake client indexer
+	if err := waitForResourceInIndexer("nodes", "", testNode.Name, string(testNode.UID), "node"); err != nil {
+		t.Fatalf("Node did not appear in fake client indexer within timeout: %v", err)
+	}
+
+	// Verify the pod can be retrieved from the fake client
+	retrievedPod, err := sandbox.fakeClient().CoreV1().Pods(testPod.Namespace).Get(ctx, testPod.Name, metav1.GetOptions{})
+	if err != nil {
+		t.Fatalf("Failed to retrieve pod from fake client: %v", err)
+	}
+	if retrievedPod.Namespace != testPod.Namespace || retrievedPod.Name != testPod.Name || retrievedPod.UID != testPod.UID {
+		t.Errorf("Retrieved pod mismatch: got namespace=%s name=%s uid=%s, want namespace=%s name=%s uid=%s",
+			retrievedPod.Namespace, retrievedPod.Name, retrievedPod.UID, testPod.Namespace, testPod.Name, testPod.UID)
+	}
+	t.Logf("Successfully retrieved pod from fake client: %s/%s", retrievedPod.Namespace, retrievedPod.Name)
+
+	// Verify the node can be retrieved from the fake client
+	retrievedNode, err := sandbox.fakeClient().CoreV1().Nodes().Get(ctx, testNode.Name, metav1.GetOptions{})
+	if err != nil {
+		t.Fatalf("Failed to retrieve node from fake client: %v", err)
+	}
+	if retrievedNode.Name != testNode.Name || retrievedNode.UID != testNode.UID {
+		t.Errorf("Retrieved node mismatch: got name=%s uid=%s, want name=%s uid=%s",
+			retrievedNode.Name, retrievedNode.UID, testNode.Name, testNode.UID)
+	}
+	t.Logf("Successfully retrieved node from fake client: %s", retrievedNode.Name)
+
+	// Wait a bit longer and verify the secret does NOT appear in the fake client indexer
+	// because secrets were registered AFTER the sandbox was created
+	t.Log("Verifying secret does NOT appear in fake client indexer...")
+	time.Sleep(500 * time.Millisecond) // Give extra time to ensure it's not just a timing issue
+
+	// First, verify we can get the informer for secrets in the fake factory
+	secretInformer, err := sandbox.fakeSharedInformerFactory().ForResource(v1.SchemeGroupVersion.WithResource("secrets"))
+	if err != nil {
+		t.Logf("Expected: Cannot get secret informer from fake factory: %v", err)
+	} else {
+		// If we can get the informer, check if the secret exists in it
+		key := "default/test-secret"
+		_, exists, err := secretInformer.Informer().GetIndexer().GetByKey(key)
+		if err != nil {
+			t.Logf("Error checking secret in fake indexer: %v", err)
+		}
+		if exists {
+			t.Error("Secret should NOT exist in fake client indexer (it was registered after sandbox creation)")
+		} else {
+			t.Log("Correctly verified: Secret does not exist in fake client indexer")
+		}
+	}
+
+	// Also verify that attempting to get the secret directly from fake client should fail
+	_, err = sandbox.fakeClient().CoreV1().Secrets(testSecret.Namespace).Get(ctx, testSecret.Name, metav1.GetOptions{})
+	if err == nil {
+		t.Error("Secret should NOT be retrievable from fake client (it was not synced)")
+	} else {
+		t.Logf("Correctly verified: Secret not retrievable from fake client: %v", err)
+	}
+
+	// Verify the secret IS in the real client (sanity check)
+	_, err = realClient.CoreV1().Secrets(testSecret.Namespace).Get(ctx, testSecret.Name, metav1.GetOptions{})
+	if err != nil {
+		t.Fatalf("Secret should exist in real client but got error: %v", err)
+	}
+	t.Log("Sanity check passed: Secret exists in real client")
+}
+
+func TestKubeClientSandboxReset(t *testing.T) {
+	ctx := context.Background()
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	node1 := test.BuildTestNode("n1", 2000, 3000, 10, nil)
+	p1 := test.BuildTestPod("p1", 100, 0, node1.Name, test.SetRSOwnerRef)
+	p2 := test.BuildTestPod("p2", 100, 0, node1.Name, test.SetRSOwnerRef)
+
+	sandbox, _, _ := setupTestSandbox(ctx, t, node1, p1, p2)
+
+	eviction1 := &policy.Eviction{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      p1.Name,
+			Namespace: p1.Namespace,
+		},
+	}
+	eviction2 := &policy.Eviction{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      p2.Name,
+			Namespace: p2.Namespace,
+		},
+	}
+
+	if err := sandbox.fakeClient().CoreV1().Pods(p1.Namespace).EvictV1(context.TODO(), eviction1); err != nil {
+		t.Fatalf("Error evicting p1: %v", err)
+	}
+	if err := sandbox.fakeClient().CoreV1().Pods(p2.Namespace).EvictV1(context.TODO(), eviction2); err != nil {
+		t.Fatalf("Error evicting p2: %v", err)
+	}
+
+	evictedPods := sandbox.evictedPodsCache.list()
+	if len(evictedPods) != 2 {
+		t.Fatalf("Expected 2 evicted pods in cache, but got %d", len(evictedPods))
+	}
+	t.Logf("Evicted pods in cache before reset: %d", len(evictedPods))
+
+	for _, evictedPod := range evictedPods {
+		if evictedPod.Namespace == "" || evictedPod.Name == "" || evictedPod.UID == "" {
+			t.Errorf("Evicted pod has empty fields: namespace=%s, name=%s, uid=%s", evictedPod.Namespace, evictedPod.Name, evictedPod.UID)
+		}
+		t.Logf("Evicted pod: %s/%s (UID: %s)", evictedPod.Namespace, evictedPod.Name, evictedPod.UID)
+	}
+
+	sandbox.reset()
+
+	evictedPodsAfterReset := sandbox.evictedPodsCache.list()
+	if len(evictedPodsAfterReset) != 0 {
+		t.Fatalf("Expected cache to be empty after reset, but found %d pods", len(evictedPodsAfterReset))
+	}
+	t.Logf("Successfully verified cache is empty after reset")
+}
+
+func TestKubeClientSandboxRestoreEvictedPods(t *testing.T) {
+	ctx := context.Background()
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	node1 := test.BuildTestNode("n1", 2000, 3000, 10, nil)
+
+	// Create test pods
+	pod1 := test.BuildTestPod("pod1", 100, 0, node1.Name, test.SetRSOwnerRef)
+	pod2 := test.BuildTestPod("pod2", 100, 0, node1.Name, test.SetRSOwnerRef)
+	pod3 := test.BuildTestPod("pod3", 100, 0, node1.Name, test.SetRSOwnerRef)
+	pod4 := test.BuildTestPod("pod4", 100, 0, node1.Name, test.SetRSOwnerRef)
+
+	sandbox, _, realClient := setupTestSandbox(ctx, t, node1, pod1, pod2, pod3, pod4)
+
+	// Evict all pods
+	for _, pod := range []*v1.Pod{pod1, pod2, pod3, pod4} {
+		eviction := &policy.Eviction{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      pod.Name,
+				Namespace: pod.Namespace,
+			},
+		}
+		if err := sandbox.fakeClient().CoreV1().Pods(pod.Namespace).EvictV1(ctx, eviction); err != nil {
+			t.Fatalf("Error evicting %s: %v", pod.Name, err)
+		}
+	}
+
+	// Delete pod2 from real client to simulate it being deleted (should skip restoration)
+	if err := realClient.CoreV1().Pods(pod2.Namespace).Delete(ctx, pod2.Name, metav1.DeleteOptions{}); err != nil {
+		t.Fatalf("Error deleting pod2 from real client: %v", err)
+	}
+
+	// Delete and recreate pod3 with different UID in real client (should skip restoration)
+	if err := realClient.CoreV1().Pods(pod3.Namespace).Delete(ctx, pod3.Name, metav1.DeleteOptions{}); err != nil {
+		t.Fatalf("Error deleting pod3 from real client: %v", err)
+	}
+	pod3New := test.BuildTestPod("pod3", 100, 0, node1.Name, test.SetRSOwnerRef)
+	// Ensure pod3New has a different UID from pod3
+	if pod3New.UID == pod3.UID {
+		pod3New.UID = "new-uid-for-pod3"
+	}
+	if _, err := realClient.CoreV1().Pods(pod3New.Namespace).Create(ctx, pod3New, metav1.CreateOptions{}); err != nil {
+		t.Fatalf("Error recreating pod3 in real client: %v", err)
+	}
+
+	// Verify evicted pods are in cache
+	evictedPods := sandbox.evictedPodsCache.list()
+	if len(evictedPods) != 4 {
+		t.Fatalf("Expected 4 evicted pods in cache, got %d", len(evictedPods))
+	}
+	t.Logf("Evicted pods in cache: %d", len(evictedPods))
+
+	// Call restoreEvictedPods
+	t.Log("Calling restoreEvictedPods...")
+	if err := sandbox.restoreEvictedPods(ctx); err != nil {
+		t.Fatalf("restoreEvictedPods failed: %v", err)
+	}
+
+	// Verify pod1 and pod4 were restored (exists in fake client with matching UID and accessible via indexer)
+	for _, pod := range []*v1.Pod{pod1, pod4} {
+		// Check restoration via fake client
+		restoredPod, err := sandbox.fakeClient().CoreV1().Pods(pod.Namespace).Get(ctx, pod.Name, metav1.GetOptions{})
+		if err != nil {
+			t.Errorf("%s should have been restored to fake client: %v", pod.Name, err)
+		} else {
+			if restoredPod.UID != pod.UID {
+				t.Errorf("Restored %s UID mismatch: got %s, want %s", pod.Name, restoredPod.UID, pod.UID)
+			}
+			t.Logf("Successfully verified %s restoration: %s/%s (UID: %s)", pod.Name, restoredPod.Namespace, restoredPod.Name, restoredPod.UID)
+		}
+
+		// Check accessibility via indexer
+		exists, err := sandbox.hasObjectInIndexer(v1.SchemeGroupVersion.WithResource("pods"), pod.Namespace, pod.Name, string(pod.UID))
+		if err != nil {
+			t.Errorf("Error checking %s in indexer: %v", pod.Name, err)
+		}
+		if !exists {
+			t.Errorf("%s should exist in fake indexer after restoration", pod.Name)
+		} else {
+			t.Logf("Successfully verified %s exists in fake indexer", pod.Name)
+		}
+	}
+
+	// Verify pod2 was NOT restored (deleted from real client)
+	_, err := sandbox.fakeClient().CoreV1().Pods(pod2.Namespace).Get(ctx, pod2.Name, metav1.GetOptions{})
+	if err == nil {
+		t.Error("pod2 should NOT have been restored (was deleted from real client)")
+	} else {
+		t.Logf("Correctly verified pod2 was not restored: %v", err)
+	}
+
+	// Verify pod3 was NOT restored with old UID (UID mismatch case)
+	// Note: pod3 may exist in fake client with NEW UID due to event handler syncing,
+	// but it should NOT have been restored with the OLD UID from evicted cache
+	pod3InFake, err := sandbox.fakeClient().CoreV1().Pods(pod3.Namespace).Get(ctx, pod3.Name, metav1.GetOptions{})
+	if err == nil {
+		// Pod3 exists, but it should have the NEW UID, not the old one
+		if pod3InFake.UID == pod3.UID {
+			t.Error("pod3 should NOT have been restored with old UID (UID mismatch should prevent restoration)")
+		} else {
+			t.Logf("Correctly verified pod3 has new UID (%s), not old UID (%s) - restoration was skipped", pod3InFake.UID, pod3.UID)
+		}
+	} else {
+		// Pod3 doesn't exist - this is also acceptable (event handlers haven't synced it yet)
+		t.Logf("pod3 not found in fake client: %v", err)
+	}
+
+	// Verify evicted pods cache is still intact (restoreEvictedPods doesn't clear it)
+	evictedPodsAfter := sandbox.evictedPodsCache.list()
+	if len(evictedPodsAfter) != 4 {
+		t.Errorf("Expected evicted pods cache to still have 4 entries, got %d", len(evictedPodsAfter))
+	}
+}
+
+func TestKubeClientSandboxRestoreEvictedPodsEmptyCache(t *testing.T) {
+	ctx := context.Background()
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	node1 := test.BuildTestNode("n1", 2000, 3000, 10, nil)
+	sandbox, _, _ := setupTestSandbox(ctx, t, node1)
+
+	// Call restoreEvictedPods with empty cache - should be a no-op
+	t.Log("Calling restoreEvictedPods with empty cache...")
+	if err := sandbox.restoreEvictedPods(ctx); err != nil {
+		t.Fatalf("restoreEvictedPods should succeed with empty cache: %v", err)
+	}
+	t.Log("Successfully verified restoreEvictedPods handles empty cache")
+}
+
+func TestEvictedPodsCache(t *testing.T) {
+	t.Run("add single pod", func(t *testing.T) {
+		const (
+			podName      = "pod1"
+			podNamespace = "default"
+			podUID       = "a1b2c3d4-e5f6-7890-abcd-ef1234567890"
+		)
+		cache := newEvictedPodsCache()
+		pod := &v1.Pod{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      podName,
+				Namespace: podNamespace,
+				UID:       podUID,
+			},
+		}
+
+		cache.add(pod)
+
+		pods := cache.list()
+		if len(pods) != 1 {
+			t.Fatalf("Expected 1 pod in cache, got %d", len(pods))
+		}
+		if pods[0].Name != podName || pods[0].Namespace != podNamespace || pods[0].UID != podUID {
+			t.Errorf("Pod data mismatch: got name=%s, namespace=%s, uid=%s", pods[0].Name, pods[0].Namespace, pods[0].UID)
+		}
+	})
+
+	t.Run("add multiple pods", func(t *testing.T) {
+		cache := newEvictedPodsCache()
+		pods := []*v1.Pod{
+			{ObjectMeta: metav1.ObjectMeta{Name: "pod1", Namespace: "default", UID: "11111111-1111-1111-1111-111111111111"}},
+			{ObjectMeta: metav1.ObjectMeta{Name: "pod2", Namespace: "kube-system", UID: "22222222-2222-2222-2222-222222222222"}},
+			{ObjectMeta: metav1.ObjectMeta{Name: "pod3", Namespace: "default", UID: "33333333-3333-3333-3333-333333333333"}},
+		}
+
+		for _, pod := range pods {
+			cache.add(pod)
+		}
+
+		cachedPods := cache.list()
+		if len(cachedPods) != 3 {
+			t.Fatalf("Expected 3 pods in cache, got %d", len(cachedPods))
+		}
+
+		podMap := make(map[string]*evictedPodInfo)
+		for _, cachedPod := range cachedPods {
+			podMap[cachedPod.UID] = cachedPod
+		}
+
+		for _, pod := range pods {
+			cached, ok := podMap[string(pod.UID)]
+			if !ok {
+				t.Errorf("Pod with UID %s not found in cache", pod.UID)
+				continue
+			}
+			if cached.Name != pod.Name || cached.Namespace != pod.Namespace {
+				t.Errorf("Pod data mismatch for UID %s: got name=%s, namespace=%s", pod.UID, cached.Name, cached.Namespace)
+			}
+		}
+	})
+
+	t.Run("add duplicate pod updates entry", func(t *testing.T) {
+		const (
+			duplicateUID   = "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee"
+			updatedPodName = "pod1-new"
+			updatedPodNS   = "kube-system"
+		)
+		cache := newEvictedPodsCache()
+		pod1 := &v1.Pod{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "pod1",
+				Namespace: "default",
+				UID:       duplicateUID,
+			},
+		}
+		pod2 := &v1.Pod{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      updatedPodName,
+				Namespace: updatedPodNS,
+				UID:       duplicateUID,
+			},
+		}
+
+		cache.add(pod1)
+		cache.add(pod2)
+
+		pods := cache.list()
+		if len(pods) != 1 {
+			t.Fatalf("Expected 1 pod in cache (duplicates should overwrite), got %d", len(pods))
+		}
+		if pods[0].Name != updatedPodName || pods[0].Namespace != updatedPodNS {
+			t.Errorf("Expected pod2 data, got name=%s, namespace=%s", pods[0].Name, pods[0].Namespace)
+		}
+	})
+
+	t.Run("list returns empty array for empty cache", func(t *testing.T) {
+		cache := newEvictedPodsCache()
+		pods := cache.list()
+		if pods == nil {
+			t.Fatal("Expected non-nil slice from list()")
+		}
+		if len(pods) != 0 {
+			t.Fatalf("Expected empty list, got %d pods", len(pods))
+		}
+	})
+
+	t.Run("list returns copies not references", func(t *testing.T) {
+		const originalPodName = "pod1"
+		cache := newEvictedPodsCache()
+		pod := &v1.Pod{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      originalPodName,
+				Namespace: "default",
+				UID:       "12345678-1234-1234-1234-123456789abc",
+			},
+		}
+		cache.add(pod)
+
+		pods1 := cache.list()
+		pods2 := cache.list()
+
+		if len(pods1) != 1 || len(pods2) != 1 {
+			t.Fatalf("Expected 1 pod in both lists")
+		}
+
+		pods1[0].Name = "modified"
+
+		if pods2[0].Name == "modified" {
+			t.Error("Modifying list result should not affect other list results (should be copies)")
+		}
+
+		pods3 := cache.list()
+		if pods3[0].Name != originalPodName {
+			t.Error("Cache data was modified, list() should return copies")
+		}
+	})
+
+	t.Run("clear empties the cache", func(t *testing.T) {
+		cache := newEvictedPodsCache()
+		cache.add(&v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "pod1", Namespace: "default", UID: "aaaa0000-0000-0000-0000-000000000001"}})
+		cache.add(&v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "pod2", Namespace: "kube-system", UID: "bbbb0000-0000-0000-0000-000000000002"}})
+
+		if len(cache.list()) != 2 {
+			t.Fatal("Expected 2 pods before clear")
+		}
+
+		cache.clear()
+
+		pods := cache.list()
+		if len(pods) != 0 {
+			t.Fatalf("Expected empty cache after clear, got %d pods", len(pods))
+		}
+	})
+
+	t.Run("clear on empty cache is safe", func(t *testing.T) {
+		cache := newEvictedPodsCache()
+		cache.clear()
+
+		pods := cache.list()
+		if len(pods) != 0 {
+			t.Fatalf("Expected empty cache, got %d pods", len(pods))
+		}
+	})
+
+	t.Run("add after clear works correctly", func(t *testing.T) {
+		cache := newEvictedPodsCache()
+		cache.add(&v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "pod1", Namespace: "default", UID: "00000001-0001-0001-0001-000000000001"}})
+		cache.clear()
+		cache.add(&v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "pod2", Namespace: "kube-system", UID: "00000002-0002-0002-0002-000000000002"}})
+
+		pods := cache.list()
+		if len(pods) != 1 {
+			t.Fatalf("Expected 1 pod after clear and add, got %d", len(pods))
+		}
+		if pods[0].Name != "pod2" {
+			t.Errorf("Expected pod2, got %s", pods[0].Name)
+		}
+	})
+}

pkg/descheduler/node/node.go

@@ -28,6 +28,7 @@ import (
 	"k8s.io/apimachinery/pkg/labels"
 	clientset "k8s.io/client-go/kubernetes"
 	listersv1 "k8s.io/client-go/listers/core/v1"
+	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/util/workqueue"
 	"k8s.io/klog/v2"
 	"sigs.k8s.io/descheduler/pkg/api"
@@ -78,6 +79,22 @@ func ReadyNodes(ctx context.Context, client clientset.Interface, nodeLister list
 	return readyNodes, nil
 }
 
+// ReadyNodesFromInterfaces converts a list of interface{} items to ready nodes.
+// Each interface{} item is expected to be a *v1.Node. Only ready nodes are returned.
+func ReadyNodesFromInterfaces(nodeInterfaces []interface{}) ([]*v1.Node, error) {
+	readyNodes := make([]*v1.Node, 0, len(nodeInterfaces))
+	for i, nodeInterface := range nodeInterfaces {
+		node, ok := nodeInterface.(*v1.Node)
+		if !ok {
+			return nil, fmt.Errorf("item at index %d is not a *v1.Node", i)
+		}
+		if IsReady(node) {
+			readyNodes = append(readyNodes, node)
+		}
+	}
+	return readyNodes, nil
+}
+
 // IsReady checks if the descheduler could run against given node.
 func IsReady(node *v1.Node) bool {
 	for i := range node.Status.Conditions {
@@ -400,3 +417,22 @@ func podMatchesInterPodAntiAffinity(nodeIndexer podutil.GetPodsAssignedToNodeFun
 
 	return false, nil
 }
+
+// BuildGetPodsAssignedToNodeFunc establishes an indexer to map the pods and their assigned nodes.
+// It returns a function to help us get all the pods that assigned to a node based on the indexer.
+func AddNodeSelectorIndexer(nodeInformer cache.SharedIndexInformer, indexerName string, nodeSelector labels.Selector) error {
+	return nodeInformer.AddIndexers(cache.Indexers{
+		indexerName: func(obj interface{}) ([]string, error) {
+			node, ok := obj.(*v1.Node)
+			if !ok {
+				return []string{}, errors.New("unexpected object")
+			}
+
+			if nodeSelector.Matches(labels.Set(node.Labels)) {
+				return []string{indexerName}, nil
+			}
+
+			return []string{}, nil
+		},
+	})
+}

pkg/descheduler/node/node_test.go

@@ -19,9 +19,12 @@ package node
 import (
 	"context"
 	"errors"
+	"sort"
+	"strings"
 	"sync"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -102,6 +105,183 @@ func TestReadyNodesWithNodeSelector(t *testing.T) {
 	}
 }
 
+func TestReadyNodesFromInterfaces(t *testing.T) {
+	node1 := test.BuildTestNode("node1", 1000, 2000, 9, nil)
+	node2 := test.BuildTestNode("node2", 1000, 2000, 9, nil)
+	node2.Status.Conditions = []v1.NodeCondition{{Type: v1.NodeReady, Status: v1.ConditionFalse}}
+	node3 := test.BuildTestNode("node3", 1000, 2000, 9, nil)
+
+	tests := []struct {
+		description    string
+		nodeInterfaces []interface{}
+		expectedCount  int
+		expectedNames  []string
+		expectError    bool
+		errorContains  string
+	}{
+		{
+			description:    "All nodes are ready",
+			nodeInterfaces: []interface{}{node1, node3},
+			expectedCount:  2,
+			expectedNames:  []string{"node1", "node3"},
+			expectError:    false,
+		},
+		{
+			description:    "One node is not ready",
+			nodeInterfaces: []interface{}{node1, node2, node3},
+			expectedCount:  2,
+			expectedNames:  []string{"node1", "node3"},
+			expectError:    false,
+		},
+		{
+			description:    "Empty list",
+			nodeInterfaces: []interface{}{},
+			expectedCount:  0,
+			expectedNames:  []string{},
+			expectError:    false,
+		},
+		{
+			description:    "Invalid type in list",
+			nodeInterfaces: []interface{}{node1, "not a node", node3},
+			expectedCount:  0,
+			expectError:    true,
+			errorContains:  "item at index 1 is not a *v1.Node",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.description, func(t *testing.T) {
+			nodes, err := ReadyNodesFromInterfaces(tc.nodeInterfaces)
+
+			if tc.expectError {
+				if err == nil {
+					t.Errorf("Expected error but got none")
+				} else if tc.errorContains != "" && !strings.Contains(err.Error(), tc.errorContains) {
+					t.Errorf("Expected error to contain '%s', got '%s'", tc.errorContains, err.Error())
+				}
+				return
+			}
+
+			if err != nil {
+				t.Errorf("Unexpected error: %v", err)
+			}
+
+			if len(nodes) != tc.expectedCount {
+				t.Errorf("Expected %d nodes, got %d", tc.expectedCount, len(nodes))
+			}
+
+			for i, expectedName := range tc.expectedNames {
+				if i >= len(nodes) {
+					t.Errorf("Missing node at index %d, expected %s", i, expectedName)
+					continue
+				}
+				if nodes[i].Name != expectedName {
+					t.Errorf("Expected node at index %d to be %s, got %s", i, expectedName, nodes[i].Name)
+				}
+			}
+		})
+	}
+}
+
+func TestAddNodeSelectorIndexer(t *testing.T) {
+	node1 := test.BuildTestNode("node1", 1000, 2000, 9, nil)
+	node1.Labels = map[string]string{"type": "compute", "zone": "us-east-1"}
+	node2 := test.BuildTestNode("node2", 1000, 2000, 9, nil)
+	node2.Labels = map[string]string{"type": "infra", "zone": "us-west-1"}
+	node3 := test.BuildTestNode("node3", 1000, 2000, 9, nil)
+	node3.Labels = map[string]string{"type": "compute", "zone": "us-west-1"}
+
+	tests := []struct {
+		description     string
+		indexerName     string
+		selectorString  string
+		expectedMatches []string
+	}{
+		{
+			description:     "Index nodes by type=compute",
+			indexerName:     "computeNodes",
+			selectorString:  "type=compute",
+			expectedMatches: []string{"node1", "node3"},
+		},
+		{
+			description:     "Index nodes by type=infra",
+			indexerName:     "infraNodes",
+			selectorString:  "type=infra",
+			expectedMatches: []string{"node2"},
+		},
+		{
+			description:     "Index nodes by zone=us-west-1",
+			indexerName:     "westZoneNodes",
+			selectorString:  "zone=us-west-1",
+			expectedMatches: []string{"node2", "node3"},
+		},
+		{
+			description:     "Index nodes with multiple labels",
+			indexerName:     "computeEastNodes",
+			selectorString:  "type=compute,zone=us-east-1",
+			expectedMatches: []string{"node1"},
+		},
+		{
+			description:     "No matching nodes",
+			indexerName:     "noMatchNodes",
+			selectorString:  "type=storage",
+			expectedMatches: []string{},
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.description, func(t *testing.T) {
+			fakeClient := fake.NewSimpleClientset(node1, node2, node3)
+			sharedInformerFactory := informers.NewSharedInformerFactory(fakeClient, 0)
+			nodeInformer := sharedInformerFactory.Core().V1().Nodes().Informer()
+
+			selector, err := labels.Parse(tc.selectorString)
+			if err != nil {
+				t.Fatalf("Failed to parse selector: %v", err)
+			}
+
+			err = AddNodeSelectorIndexer(nodeInformer, tc.indexerName, selector)
+			if err != nil {
+				t.Fatalf("AddNodeSelectorIndexer failed: %v", err)
+			}
+
+			stopChannel := make(chan struct{})
+			sharedInformerFactory.Start(stopChannel)
+			sharedInformerFactory.WaitForCacheSync(stopChannel)
+			defer close(stopChannel)
+
+			indexer := nodeInformer.GetIndexer()
+			objs, err := indexer.ByIndex(tc.indexerName, tc.indexerName)
+			if err != nil {
+				t.Errorf("Failed to query indexer: %v", err)
+				return
+			}
+
+			// Extract node names from the results
+			actualMatches := make([]string, 0, len(objs))
+			for _, obj := range objs {
+				node, ok := obj.(*v1.Node)
+				if !ok {
+					t.Errorf("Expected *v1.Node, got %T", obj)
+					continue
+				}
+				actualMatches = append(actualMatches, node.Name)
+			}
+
+			// Sort both slices for consistent comparison
+			sort.Strings(actualMatches)
+			expectedMatches := make([]string, len(tc.expectedMatches))
+			copy(expectedMatches, tc.expectedMatches)
+			sort.Strings(expectedMatches)
+
+			// Compare using cmp.Diff
+			if diff := cmp.Diff(expectedMatches, actualMatches); diff != "" {
+				t.Errorf("Node matches mismatch (-want +got):\n%s", diff)
+			}
+		})
+	}
+}
+
 func TestIsNodeUnschedulable(t *testing.T) {
 	tests := []struct {
 		description     string

pkg/framework/fake/fake.go

@@ -23,6 +23,7 @@ type HandleImpl struct {
 	PodEvictorImpl                *evictions.PodEvictor
 	MetricsCollectorImpl          *metricscollector.MetricsCollector
 	PrometheusClientImpl          promapi.Client
+	PluginInstanceIDImpl          string
 }
 
 var _ frameworktypes.Handle = &HandleImpl{}
@@ -62,3 +63,7 @@ func (hi *HandleImpl) PreEvictionFilter(pod *v1.Pod) bool {
 func (hi *HandleImpl) Evict(ctx context.Context, pod *v1.Pod, opts evictions.EvictOptions) error {
 	return hi.PodEvictorImpl.EvictPod(ctx, pod, opts)
 }
+
+func (hi *HandleImpl) PluginInstanceID() string {
+	return hi.PluginInstanceIDImpl
+}

pkg/framework/fake/plugin/fake.go

@@ -73,6 +73,22 @@ func NewPluginFncFromFake(fp *FakePlugin) pluginregistry.PluginBuilder {
 	}
 }
 
+func NewPluginFncFromFakeWithReactor(fp *FakePlugin, callback func(ActionImpl)) pluginregistry.PluginBuilder {
+	return func(ctx context.Context, args runtime.Object, handle frameworktypes.Handle) (frameworktypes.Plugin, error) {
+		fakePluginArgs, ok := args.(*FakePluginArgs)
+		if !ok {
+			return nil, fmt.Errorf("want args to be of type FakePluginArgs, got %T", args)
+		}
+
+		fp.handle = handle
+		fp.args = fakePluginArgs
+
+		callback(ActionImpl{handle: fp.handle})
+
+		return fp, nil
+	}
+}
+
 // New builds plugin from its arguments while passing a handle
 func New(ctx context.Context, args runtime.Object, handle frameworktypes.Handle) (frameworktypes.Plugin, error) {
 	fakePluginArgs, ok := args.(*FakePluginArgs)
@@ -408,3 +424,55 @@ func (d *FakeFilterPlugin) handleBoolAction(action Action) bool {
 	}
 	panic(fmt.Errorf("unhandled %q action", action.GetExtensionPoint()))
 }
+
+// RegisterFakePlugin registers a FakePlugin with the given registry
+func RegisterFakePlugin(name string, plugin *FakePlugin, registry pluginregistry.Registry) {
+	pluginregistry.Register(
+		name,
+		NewPluginFncFromFake(plugin),
+		&FakePlugin{},
+		&FakePluginArgs{},
+		ValidateFakePluginArgs,
+		SetDefaults_FakePluginArgs,
+		registry,
+	)
+}
+
+// RegisterFakeDeschedulePlugin registers a FakeDeschedulePlugin with the given registry
+func RegisterFakeDeschedulePlugin(name string, plugin *FakeDeschedulePlugin, registry pluginregistry.Registry) {
+	pluginregistry.Register(
+		name,
+		NewFakeDeschedulePluginFncFromFake(plugin),
+		&FakeDeschedulePlugin{},
+		&FakeDeschedulePluginArgs{},
+		ValidateFakePluginArgs,
+		SetDefaults_FakePluginArgs,
+		registry,
+	)
+}
+
+// RegisterFakeBalancePlugin registers a FakeBalancePlugin with the given registry
+func RegisterFakeBalancePlugin(name string, plugin *FakeBalancePlugin, registry pluginregistry.Registry) {
+	pluginregistry.Register(
+		name,
+		NewFakeBalancePluginFncFromFake(plugin),
+		&FakeBalancePlugin{},
+		&FakeBalancePluginArgs{},
+		ValidateFakePluginArgs,
+		SetDefaults_FakePluginArgs,
+		registry,
+	)
+}
+
+// RegisterFakeFilterPlugin registers a FakeFilterPlugin with the given registry
+func RegisterFakeFilterPlugin(name string, plugin *FakeFilterPlugin, registry pluginregistry.Registry) {
+	pluginregistry.Register(
+		name,
+		NewFakeFilterPluginFncFromFake(plugin),
+		&FakeFilterPlugin{},
+		&FakeFilterPluginArgs{},
+		ValidateFakePluginArgs,
+		SetDefaults_FakePluginArgs,
+		registry,
+	)
+}

pkg/framework/fake/plugin/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/defaultevictor/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/defaultevictor/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/example/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/example/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/nodeutilization/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/nodeutilization/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/podlifetime/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/podlifetime/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removeduplicates/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removeduplicates/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removefailedpods/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removefailedpods/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removepodshavingtoomanyrestarts/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removepodshavingtoomanyrestarts/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removepodsviolatinginterpodantiaffinity/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removepodsviolatinginterpodantiaffinity/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removepodsviolatingnodeaffinity/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removepodsviolatingnodeaffinity/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removepodsviolatingnodetaints/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removepodsviolatingnodetaints/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removepodsviolatingtopologyspreadconstraint/zz_generated.deepcopy.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/plugins/removepodsviolatingtopologyspreadconstraint/zz_generated.defaults.go

@@ -2,7 +2,7 @@
 // +build !ignore_autogenerated
 
 /*
-Copyright 2025 The Kubernetes Authors.
+Copyright 2026 The Kubernetes Authors.
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.

pkg/framework/profile/profile.go

@@ -78,6 +78,14 @@ type handleImpl struct {
 
 var _ frameworktypes.Handle = &handleImpl{}
 
+// pluginHandle wraps a shared handleImpl and adds a plugin-specific instance ID
+type pluginHandle struct {
+	*handleImpl
+	pluginInstanceID string
+}
+
+var _ frameworktypes.Handle = &pluginHandle{}
+
 // ClientSet retrieves kube client set
 func (hi *handleImpl) ClientSet() clientset.Interface {
 	return hi.clientSet
@@ -106,6 +114,17 @@ func (hi *handleImpl) Evictor() frameworktypes.Evictor {
 	return hi.evictor
 }
 
+// PluginInstanceID returns an empty string for the base handle.
+// Plugins should receive a pluginHandle which has a specific instance ID.
+func (hi *handleImpl) PluginInstanceID() string {
+	panic(fmt.Errorf("Not implemented"))
+}
+
+// PluginInstanceID returns a unique identifier for this plugin instance.
+func (ph *pluginHandle) PluginInstanceID() string {
+	return ph.pluginInstanceID
+}
+
 type filterPlugin interface {
 	frameworktypes.Plugin
 	Filter(pod *v1.Pod) bool
@@ -142,6 +161,7 @@ type handleImplOpts struct {
 	getPodsAssignedToNodeFunc podutil.GetPodsAssignedToNodeFunc
 	podEvictor                *evictions.PodEvictor
 	metricsCollector          *metricscollector.MetricsCollector
+	profileInstanceID         string
 }
 
 // WithClientSet sets clientSet for the scheduling frameworkImpl.
@@ -182,6 +202,14 @@ func WithMetricsCollector(metricsCollector *metricscollector.MetricsCollector) O
 	}
 }
 
+// WithProfileInstanceID sets the profile instance ID for the handle.
+// This will be used to construct unique plugin instance IDs.
+func WithProfileInstanceID(profileInstanceID string) Option {
+	return func(o *handleImplOpts) {
+		o.profileInstanceID = profileInstanceID
+	}
+}
+
 func getPluginConfig(pluginName string, pluginConfigs []api.PluginConfig) (*api.PluginConfig, int) {
 	for idx, pluginConfig := range pluginConfigs {
 		if pluginConfig.Name == pluginName {
@@ -191,7 +219,7 @@ func getPluginConfig(pluginName string, pluginConfigs []api.PluginConfig) (*api.
 	return nil, 0
 }
 
-func buildPlugin(ctx context.Context, config api.DeschedulerProfile, pluginName string, handle *handleImpl, reg pluginregistry.Registry) (frameworktypes.Plugin, error) {
+func buildPlugin(ctx context.Context, config api.DeschedulerProfile, pluginName string, handle frameworktypes.Handle, reg pluginregistry.Registry) (frameworktypes.Plugin, error) {
 	pc, _ := getPluginConfig(pluginName, config.PluginConfigs)
 	if pc == nil {
 		klog.ErrorS(fmt.Errorf("unable to get plugin config"), "skipping plugin", "plugin", pluginName, "profile", config.Name)
@@ -272,6 +300,7 @@ func NewProfile(ctx context.Context, config api.DeschedulerProfile, reg pluginre
 		return nil, fmt.Errorf("profile %q configures preEvictionFilter extension point of non-existing plugins: %v", config.Name, sets.New(config.Plugins.PreEvictionFilter.Enabled...).Difference(pi.preEvictionFilter))
 	}
 
+	// Create a base handle that will be used as a template for plugin-specific handles
 	handle := &handleImpl{
 		clientSet:                 hOpts.clientSet,
 		getPodsAssignedToNodeFunc: hOpts.getPodsAssignedToNodeFunc,
@@ -284,20 +313,26 @@ func NewProfile(ctx context.Context, config api.DeschedulerProfile, reg pluginre
 		prometheusClient: hOpts.prometheusClient,
 	}
 
+	// Collect all unique plugin names across all extension points
 	pluginNames := append(config.Plugins.Deschedule.Enabled, config.Plugins.Balance.Enabled...)
 	pluginNames = append(pluginNames, config.Plugins.Filter.Enabled...)
 	pluginNames = append(pluginNames, config.Plugins.PreEvictionFilter.Enabled...)
 
+	// Build each unique plugin only once with a unique plugin instance ID
 	plugins := make(map[string]frameworktypes.Plugin)
-	for _, plugin := range sets.New(pluginNames...).UnsortedList() {
-		pg, err := buildPlugin(ctx, config, plugin, handle, reg)
+	for idx, pluginName := range sets.New(pluginNames...).UnsortedList() {
+		ph := &pluginHandle{
+			handleImpl:       handle,
+			pluginInstanceID: fmt.Sprintf("%s-%d", hOpts.profileInstanceID, idx),
+		}
+		pg, err := buildPlugin(ctx, config, pluginName, ph, reg)
 		if err != nil {
-			return nil, fmt.Errorf("unable to build %v plugin: %v", plugin, err)
+			return nil, fmt.Errorf("unable to build %v plugin: %v", pluginName, err)
 		}
 		if pg == nil {
-			return nil, fmt.Errorf("got empty %v plugin build", plugin)
+			return nil, fmt.Errorf("got empty %v plugin build", pluginName)
 		}
-		plugins[plugin] = pg
+		plugins[pluginName] = pg
 	}
 
 	// Later, when a default list of plugins and their extension points is established,

pkg/framework/profile/profile_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"sort"
+	"strings"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -26,7 +27,60 @@ import (
 	testutils "sigs.k8s.io/descheduler/test"
 )
 
+// registerDefaultEvictor registers the DefaultEvictor plugin with the given registry
+func registerDefaultEvictor(registry pluginregistry.Registry) {
+	pluginregistry.Register(
+		defaultevictor.PluginName,
+		defaultevictor.New,
+		&defaultevictor.DefaultEvictor{},
+		&defaultevictor.DefaultEvictorArgs{},
+		defaultevictor.ValidateDefaultEvictorArgs,
+		defaultevictor.SetDefaults_DefaultEvictorArgs,
+		registry,
+	)
+}
+
 func TestProfileDescheduleBalanceExtensionPointsEviction(t *testing.T) {
+	// Helper to build profile config with default Filter and PreEvictionFilter
+	buildProfileConfig := func(name string, descheduleEnabled, balanceEnabled bool) api.DeschedulerProfile {
+		config := api.DeschedulerProfile{
+			Name: name,
+			PluginConfigs: []api.PluginConfig{
+				{
+					Name: defaultevictor.PluginName,
+					Args: &defaultevictor.DefaultEvictorArgs{
+						PriorityThreshold: &api.PriorityThreshold{
+							Value: nil,
+						},
+					},
+				},
+				{
+					Name: "FakePlugin",
+					Args: &fakeplugin.FakePluginArgs{},
+				},
+			},
+			Plugins: api.Plugins{
+				Filter: api.PluginSet{
+					Enabled: []string{defaultevictor.PluginName},
+				},
+				PreEvictionFilter: api.PluginSet{
+					Enabled: []string{defaultevictor.PluginName},
+				},
+			},
+		}
+		if descheduleEnabled {
+			config.Plugins.Deschedule = api.PluginSet{
+				Enabled: []string{"FakePlugin"},
+			}
+		}
+		if balanceEnabled {
+			config.Plugins.Balance = api.PluginSet{
+				Enabled: []string{"FakePlugin"},
+			}
+		}
+		return config
+	}
+
 	tests := []struct {
 		name             string
 		config           api.DeschedulerProfile
@@ -35,133 +89,25 @@ func TestProfileDescheduleBalanceExtensionPointsEviction(t *testing.T) {
 	}{
 		{
 			name:             "profile with deschedule extension point enabled single eviction",
-			config: api.DeschedulerProfile{
-				Name: "strategy-test-profile-with-deschedule",
-				PluginConfigs: []api.PluginConfig{
-					{
-						Name: defaultevictor.PluginName,
-						Args: &defaultevictor.DefaultEvictorArgs{
-							PriorityThreshold: &api.PriorityThreshold{
-								Value: nil,
-							},
-						},
-					},
-					{
-						Name: "FakePlugin",
-						Args: &fakeplugin.FakePluginArgs{},
-					},
-				},
-				Plugins: api.Plugins{
-					Deschedule: api.PluginSet{
-						Enabled: []string{"FakePlugin"},
-					},
-					Filter: api.PluginSet{
-						Enabled: []string{defaultevictor.PluginName},
-					},
-					PreEvictionFilter: api.PluginSet{
-						Enabled: []string{defaultevictor.PluginName},
-					},
-				},
-			},
+			config:           buildProfileConfig("strategy-test-profile-with-deschedule", true, false),
 			extensionPoint:   frameworktypes.DescheduleExtensionPoint,
 			expectedEviction: true,
 		},
 		{
 			name:             "profile with balance extension point enabled single eviction",
-			config: api.DeschedulerProfile{
-				Name: "strategy-test-profile-with-balance",
-				PluginConfigs: []api.PluginConfig{
-					{
-						Name: defaultevictor.PluginName,
-						Args: &defaultevictor.DefaultEvictorArgs{
-							PriorityThreshold: &api.PriorityThreshold{
-								Value: nil,
-							},
-						},
-					},
-					{
-						Name: "FakePlugin",
-						Args: &fakeplugin.FakePluginArgs{},
-					},
-				},
-				Plugins: api.Plugins{
-					Balance: api.PluginSet{
-						Enabled: []string{"FakePlugin"},
-					},
-					Filter: api.PluginSet{
-						Enabled: []string{defaultevictor.PluginName},
-					},
-					PreEvictionFilter: api.PluginSet{
-						Enabled: []string{defaultevictor.PluginName},
-					},
-				},
-			},
+			config:           buildProfileConfig("strategy-test-profile-with-balance", false, true),
 			extensionPoint:   frameworktypes.BalanceExtensionPoint,
 			expectedEviction: true,
 		},
 		{
 			name:             "profile with deschedule extension point balance enabled no eviction",
-			config: api.DeschedulerProfile{
-				Name: "strategy-test-profile-with-deschedule",
-				PluginConfigs: []api.PluginConfig{
-					{
-						Name: defaultevictor.PluginName,
-						Args: &defaultevictor.DefaultEvictorArgs{
-							PriorityThreshold: &api.PriorityThreshold{
-								Value: nil,
-							},
-						},
-					},
-					{
-						Name: "FakePlugin",
-						Args: &fakeplugin.FakePluginArgs{},
-					},
-				},
-				Plugins: api.Plugins{
-					Balance: api.PluginSet{
-						Enabled: []string{"FakePlugin"},
-					},
-					Filter: api.PluginSet{
-						Enabled: []string{defaultevictor.PluginName},
-					},
-					PreEvictionFilter: api.PluginSet{
-						Enabled: []string{defaultevictor.PluginName},
-					},
-				},
-			},
+			config:           buildProfileConfig("strategy-test-profile-with-balance", false, true),
 			extensionPoint:   frameworktypes.DescheduleExtensionPoint,
 			expectedEviction: false,
 		},
 		{
 			name:             "profile with balance extension point deschedule enabled no eviction",
-			config: api.DeschedulerProfile{
-				Name: "strategy-test-profile-with-deschedule",
-				PluginConfigs: []api.PluginConfig{
-					{
-						Name: defaultevictor.PluginName,
-						Args: &defaultevictor.DefaultEvictorArgs{
-							PriorityThreshold: &api.PriorityThreshold{
-								Value: nil,
-							},
-						},
-					},
-					{
-						Name: "FakePlugin",
-						Args: &fakeplugin.FakePluginArgs{},
-					},
-				},
-				Plugins: api.Plugins{
-					Deschedule: api.PluginSet{
-						Enabled: []string{"FakePlugin"},
-					},
-					Filter: api.PluginSet{
-						Enabled: []string{defaultevictor.PluginName},
-					},
-					PreEvictionFilter: api.PluginSet{
-						Enabled: []string{defaultevictor.PluginName},
-					},
-				},
-			},
+			config:           buildProfileConfig("strategy-test-profile-with-deschedule", true, false),
 			extensionPoint:   frameworktypes.BalanceExtensionPoint,
 			expectedEviction: false,
 		},
@@ -206,25 +152,9 @@ func TestProfileDescheduleBalanceExtensionPointsEviction(t *testing.T) {
 			}
 
 			pluginregistry.PluginRegistry = pluginregistry.NewRegistry()
-			pluginregistry.Register(
-				"FakePlugin",
-				fakeplugin.NewPluginFncFromFake(&fakePlugin),
-				&fakeplugin.FakePlugin{},
-				&fakeplugin.FakePluginArgs{},
-				fakeplugin.ValidateFakePluginArgs,
-				fakeplugin.SetDefaults_FakePluginArgs,
-				pluginregistry.PluginRegistry,
-			)
+			fakeplugin.RegisterFakePlugin("FakePlugin", &fakePlugin, pluginregistry.PluginRegistry)
 
-			pluginregistry.Register(
-				defaultevictor.PluginName,
-				defaultevictor.New,
-				&defaultevictor.DefaultEvictor{},
-				&defaultevictor.DefaultEvictorArgs{},
-				defaultevictor.ValidateDefaultEvictorArgs,
-				defaultevictor.SetDefaults_DefaultEvictorArgs,
-				pluginregistry.PluginRegistry,
-			)
+			registerDefaultEvictor(pluginregistry.PluginRegistry)
 
 			client := fakeclientset.NewSimpleClientset(n1, n2, p1)
 			var evictedPods []string
@@ -319,56 +249,13 @@ func TestProfileExtensionPoints(t *testing.T) {
 		fakeBalancePlugin := &fakeplugin.FakeBalancePlugin{PluginName: balancePluginName}
 		fakeFilterPlugin := &fakeplugin.FakeFilterPlugin{PluginName: filterPluginName}
 
-		pluginregistry.Register(
-			fakePluginName,
-			fakeplugin.NewPluginFncFromFake(fakePlugin),
-			&fakeplugin.FakePlugin{},
-			&fakeplugin.FakePluginArgs{},
-			fakeplugin.ValidateFakePluginArgs,
-			fakeplugin.SetDefaults_FakePluginArgs,
-			pluginregistry.PluginRegistry,
-		)
-
-		pluginregistry.Register(
-			deschedulePluginName,
-			fakeplugin.NewFakeDeschedulePluginFncFromFake(fakeDeschedulePlugin),
-			&fakeplugin.FakeDeschedulePlugin{},
-			&fakeplugin.FakeDeschedulePluginArgs{},
-			fakeplugin.ValidateFakePluginArgs,
-			fakeplugin.SetDefaults_FakePluginArgs,
-			pluginregistry.PluginRegistry,
-		)
-
-		pluginregistry.Register(
-			balancePluginName,
-			fakeplugin.NewFakeBalancePluginFncFromFake(fakeBalancePlugin),
-			&fakeplugin.FakeBalancePlugin{},
-			&fakeplugin.FakeBalancePluginArgs{},
-			fakeplugin.ValidateFakePluginArgs,
-			fakeplugin.SetDefaults_FakePluginArgs,
-			pluginregistry.PluginRegistry,
-		)
-
-		pluginregistry.Register(
-			filterPluginName,
-			fakeplugin.NewFakeFilterPluginFncFromFake(fakeFilterPlugin),
-			&fakeplugin.FakeFilterPlugin{},
-			&fakeplugin.FakeFilterPluginArgs{},
-			fakeplugin.ValidateFakePluginArgs,
-			fakeplugin.SetDefaults_FakePluginArgs,
-			pluginregistry.PluginRegistry,
-		)
+		fakeplugin.RegisterFakePlugin(fakePluginName, fakePlugin, pluginregistry.PluginRegistry)
+		fakeplugin.RegisterFakeDeschedulePlugin(deschedulePluginName, fakeDeschedulePlugin, pluginregistry.PluginRegistry)
+		fakeplugin.RegisterFakeBalancePlugin(balancePluginName, fakeBalancePlugin, pluginregistry.PluginRegistry)
+		fakeplugin.RegisterFakeFilterPlugin(filterPluginName, fakeFilterPlugin, pluginregistry.PluginRegistry)
 	}
 
-	pluginregistry.Register(
-		defaultevictor.PluginName,
-		defaultevictor.New,
-		&defaultevictor.DefaultEvictor{},
-		&defaultevictor.DefaultEvictorArgs{},
-		defaultevictor.ValidateDefaultEvictorArgs,
-		defaultevictor.SetDefaults_DefaultEvictorArgs,
-		pluginregistry.PluginRegistry,
-	)
+	registerDefaultEvictor(pluginregistry.PluginRegistry)
 
 	client := fakeclientset.NewSimpleClientset(n1, n2, p1)
 	var evictedPods []string
@@ -524,15 +411,7 @@ func TestProfileExtensionPointOrdering(t *testing.T) {
 		})
 
 		// plugin implementing Filter extension point
-		pluginregistry.Register(
-			pluginName,
-			fakeplugin.NewFakeFilterPluginFncFromFake(fakeFilterPlugin),
-			&fakeplugin.FakeFilterPlugin{},
-			&fakeplugin.FakeFilterPluginArgs{},
-			fakeplugin.ValidateFakePluginArgs,
-			fakeplugin.SetDefaults_FakePluginArgs,
-			pluginregistry.PluginRegistry,
-		)
+		fakeplugin.RegisterFakeFilterPlugin(pluginName, fakeFilterPlugin, pluginregistry.PluginRegistry)
 
 		fakePluginName := fmt.Sprintf("FakePlugin_%v", i)
 		fakePlugin := fakeplugin.FakePlugin{}
@@ -557,26 +436,10 @@ func TestProfileExtensionPointOrdering(t *testing.T) {
 			return true, false, nil
 		})
 
-		pluginregistry.Register(
-			fakePluginName,
-			fakeplugin.NewPluginFncFromFake(&fakePlugin),
-			&fakeplugin.FakePlugin{},
-			&fakeplugin.FakePluginArgs{},
-			fakeplugin.ValidateFakePluginArgs,
-			fakeplugin.SetDefaults_FakePluginArgs,
-			pluginregistry.PluginRegistry,
-		)
+		fakeplugin.RegisterFakePlugin(fakePluginName, &fakePlugin, pluginregistry.PluginRegistry)
 	}
 
-	pluginregistry.Register(
-		defaultevictor.PluginName,
-		defaultevictor.New,
-		&defaultevictor.DefaultEvictor{},
-		&defaultevictor.DefaultEvictorArgs{},
-		defaultevictor.ValidateDefaultEvictorArgs,
-		defaultevictor.SetDefaults_DefaultEvictorArgs,
-		pluginregistry.PluginRegistry,
-	)
+	registerDefaultEvictor(pluginregistry.PluginRegistry)
 
 	client := fakeclientset.NewSimpleClientset(n1, n2, p1)
 	var evictedPods []string
@@ -680,3 +543,325 @@ func TestProfileExtensionPointOrdering(t *testing.T) {
 		t.Errorf("check for balance invocation order failed. Results are not deep equal. mismatch (-want +got):\n%s", diff)
 	}
 }
+
+// verifyInstanceIDsMatch verifies that instance IDs captured at creation, deschedule, and balance match
+func verifyInstanceIDsMatch(t *testing.T, profileInstanceID string, pluginNames []string, creationIDs, descheduleIDs, balanceIDs map[string]string) {
+	for _, pluginName := range pluginNames {
+		creationID := creationIDs[pluginName]
+		descheduleID := descheduleIDs[pluginName]
+		balanceID := balanceIDs[pluginName]
+
+		if creationID == "" {
+			t.Errorf("Profile %s, plugin %s: plugin creation did not capture instance ID", profileInstanceID, pluginName)
+		}
+		if descheduleID == "" {
+			t.Errorf("Profile %s, plugin %s: deschedule extension point did not capture instance ID", profileInstanceID, pluginName)
+		}
+		if balanceID == "" {
+			t.Errorf("Profile %s, plugin %s: balance extension point did not capture instance ID", profileInstanceID, pluginName)
+		}
+
+		// Verify all IDs match
+		if creationID != descheduleID {
+			t.Errorf("Profile %s, plugin %s: instance ID mismatch - creation: %s, deschedule: %s", profileInstanceID, pluginName, creationID, descheduleID)
+		}
+		if creationID != balanceID {
+			t.Errorf("Profile %s, plugin %s: instance ID mismatch - creation: %s, balance: %s", profileInstanceID, pluginName, creationID, balanceID)
+		}
+		if descheduleID != balanceID {
+			t.Errorf("Profile %s, plugin %s: instance ID mismatch - deschedule: %s, balance: %s", profileInstanceID, pluginName, descheduleID, balanceID)
+		}
+	}
+}
+
+// verifyInstanceIDFormat verifies that instance IDs have correct format and sequential indices
+func verifyInstanceIDFormat(t *testing.T, profileInstanceID string, pluginNames []string, pluginIDs map[string]string) sets.Set[string] {
+	if len(pluginIDs) != len(pluginNames) {
+		t.Errorf("Profile %s: expected %d plugins to be invoked, got %d", profileInstanceID, len(pluginNames), len(pluginIDs))
+	}
+
+	// Collect all instance IDs for this profile
+	profileInstanceIDs := sets.New[string]()
+	for pluginName, instanceID := range pluginIDs {
+		if instanceID == "" {
+			t.Errorf("Profile %s, plugin %s: expected instance ID to be set, got empty string", profileInstanceID, pluginName)
+		}
+		profileInstanceIDs.Insert(instanceID)
+	}
+
+	// Verify all IDs within this profile are unique
+	if profileInstanceIDs.Len() != len(pluginIDs) {
+		t.Errorf("Profile %s: duplicate instance IDs found", profileInstanceID)
+	}
+
+	// Verify all IDs match the expected format: "{profileInstanceID}-{index}"
+	// and contain sequential indices from 0 to n-1
+	expectedIndices := sets.New[int]()
+	for i := 0; i < len(pluginNames); i++ {
+		expectedIndices.Insert(i)
+	}
+	actualIndices := sets.New[int]()
+	for pluginName, instanceID := range pluginIDs {
+		var idx int
+		expectedPrefix := profileInstanceID + "-"
+		if !strings.HasPrefix(instanceID, expectedPrefix) {
+			t.Errorf("Profile %s, plugin %s: instance ID %s does not start with %s", profileInstanceID, pluginName, instanceID, expectedPrefix)
+			continue
+		}
+		_, err := fmt.Sscanf(instanceID, profileInstanceID+"-%d", &idx)
+		if err != nil {
+			t.Errorf("Profile %s, plugin %s: instance ID %s does not match expected format", profileInstanceID, pluginName, instanceID)
+			continue
+		}
+		actualIndices.Insert(idx)
+	}
+	// Verify we have indices 0 through n-1
+	diff := cmp.Diff(expectedIndices, actualIndices)
+	if diff != "" {
+		t.Errorf("Profile %s: instance ID indices mismatch (-want +got):\n%s", profileInstanceID, diff)
+	}
+
+	return profileInstanceIDs
+}
+
+func TestPluginInstanceIDs(t *testing.T) {
+	tests := []struct {
+		name     string
+		profiles []struct {
+			profileInstanceID string
+			pluginNames       []string
+		}
+	}{
+		{
+			name: "single plugin gets instance ID",
+			profiles: []struct {
+				profileInstanceID string
+				pluginNames       []string
+			}{
+				{
+					profileInstanceID: "0",
+					pluginNames:       []string{"TestPlugin"},
+				},
+			},
+		},
+		{
+			name: "two plugins get different instance IDs",
+			profiles: []struct {
+				profileInstanceID string
+				pluginNames       []string
+			}{
+				{
+					profileInstanceID: "0",
+					pluginNames:       []string{"Plugin_0", "Plugin_1"},
+				},
+			},
+		},
+		{
+			name: "three profiles with two plugins each get unique instance IDs",
+			profiles: []struct {
+				profileInstanceID string
+				pluginNames       []string
+			}{
+				{
+					profileInstanceID: "0",
+					pluginNames:       []string{"Plugin_A", "Plugin_B"},
+				},
+				{
+					profileInstanceID: "1",
+					pluginNames:       []string{"Plugin_C", "Plugin_D"},
+				},
+				{
+					profileInstanceID: "2",
+					pluginNames:       []string{"Plugin_E", "Plugin_F"},
+				},
+			},
+		},
+		{
+			name: "three profiles with same plugin names get different instance IDs per profile",
+			profiles: []struct {
+				profileInstanceID string
+				pluginNames       []string
+			}{
+				{
+					profileInstanceID: "0",
+					pluginNames:       []string{"CommonPlugin_X", "CommonPlugin_Y"},
+				},
+				{
+					profileInstanceID: "1",
+					pluginNames:       []string{"CommonPlugin_X", "CommonPlugin_Y"},
+				},
+				{
+					profileInstanceID: "2",
+					pluginNames:       []string{"CommonPlugin_X", "CommonPlugin_Y"},
+				},
+			},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			ctx, cancel := context.WithCancel(context.TODO())
+			defer cancel()
+
+			n1 := testutils.BuildTestNode("n1", 2000, 3000, 10, nil)
+			n2 := testutils.BuildTestNode("n2", 2000, 3000, 10, nil)
+			nodes := []*v1.Node{n1, n2}
+
+			// Track instance IDs by profile from different stages
+			profileDescheduleIDs := make(map[string]map[string]string) // profileInstanceID -> pluginName -> instanceID (from Deschedule execution)
+			profileBalanceIDs := make(map[string]map[string]string)    // profileInstanceID -> pluginName -> instanceID (from Balance execution)
+			profileCreationIDs := make(map[string]map[string]string)   // profileInstanceID -> pluginName -> instanceID (from plugin creation)
+			registry := pluginregistry.NewRegistry()
+
+			// Collect all distinct plugin names across all profiles
+			allPluginNames := sets.New[string]()
+			for _, profileCfg := range test.profiles {
+				allPluginNames.Insert(profileCfg.pluginNames...)
+			}
+
+			// Helper function to validate and store instance ID
+			captureInstanceID := func(instanceID, pluginName string, targetMap map[string]map[string]string) {
+				parts := strings.Split(instanceID, "-")
+				if len(parts) < 2 {
+					t.Fatalf("Plugin %s: instance ID %s does not have expected format 'profileID-index'", pluginName, instanceID)
+				}
+				profileID := parts[0]
+				if targetMap[profileID] == nil {
+					targetMap[profileID] = make(map[string]string)
+				}
+				targetMap[profileID][pluginName] = instanceID
+			}
+
+			// Register all plugins before creating profiles
+			for _, pluginName := range allPluginNames.UnsortedList() {
+				// Capture plugin name for closure
+				name := pluginName
+
+				pluginregistry.Register(
+					pluginName,
+					func(ctx context.Context, args runtime.Object, handle frameworktypes.Handle) (frameworktypes.Plugin, error) {
+						fakePlugin := &fakeplugin.FakePlugin{PluginName: name}
+
+						fakePlugin.AddReactor(string(frameworktypes.DescheduleExtensionPoint), func(action fakeplugin.Action) (handled, filter bool, err error) {
+							if dAction, ok := action.(fakeplugin.DescheduleAction); ok {
+								captureInstanceID(dAction.Handle().PluginInstanceID(), name, profileDescheduleIDs)
+								return true, false, nil
+							}
+							return false, false, nil
+						})
+
+						fakePlugin.AddReactor(string(frameworktypes.BalanceExtensionPoint), func(action fakeplugin.Action) (handled, filter bool, err error) {
+							if bAction, ok := action.(fakeplugin.BalanceAction); ok {
+								captureInstanceID(bAction.Handle().PluginInstanceID(), name, profileBalanceIDs)
+								return true, false, nil
+							}
+							return false, false, nil
+						})
+
+						// Use NewPluginFncFromFakeWithReactor to wrap and capture instance ID at creation
+						builder := fakeplugin.NewPluginFncFromFakeWithReactor(fakePlugin, func(action fakeplugin.ActionImpl) {
+							captureInstanceID(action.Handle().PluginInstanceID(), name, profileCreationIDs)
+						})
+
+						return builder(ctx, args, handle)
+					},
+					&fakeplugin.FakePlugin{},
+					&fakeplugin.FakePluginArgs{},
+					fakeplugin.ValidateFakePluginArgs,
+					fakeplugin.SetDefaults_FakePluginArgs,
+					registry,
+				)
+			}
+
+			client := fakeclientset.NewSimpleClientset(n1, n2)
+			handle, podEvictor, err := frameworktesting.InitFrameworkHandle(
+				ctx,
+				client,
+				nil,
+				defaultevictor.DefaultEvictorArgs{},
+				nil,
+			)
+			if err != nil {
+				t.Fatalf("Unable to initialize a framework handle: %v", err)
+			}
+
+			// Create all profiles
+			var profiles []*profileImpl
+			for _, profileCfg := range test.profiles {
+
+				var pluginConfigs []api.PluginConfig
+				for _, pluginName := range profileCfg.pluginNames {
+					pluginConfigs = append(pluginConfigs, api.PluginConfig{
+						Name: pluginName,
+						Args: &fakeplugin.FakePluginArgs{},
+					})
+				}
+
+				prfl, err := NewProfile(
+					ctx,
+					api.DeschedulerProfile{
+						Name:          "test-profile",
+						PluginConfigs: pluginConfigs,
+						Plugins: api.Plugins{
+							Deschedule: api.PluginSet{
+								Enabled: profileCfg.pluginNames,
+							},
+							Balance: api.PluginSet{
+								Enabled: profileCfg.pluginNames,
+							},
+						},
+					},
+					registry,
+					WithClientSet(client),
+					WithSharedInformerFactory(handle.SharedInformerFactoryImpl),
+					WithPodEvictor(podEvictor),
+					WithGetPodsAssignedToNodeFnc(handle.GetPodsAssignedToNodeFuncImpl),
+					WithProfileInstanceID(profileCfg.profileInstanceID),
+				)
+				if err != nil {
+					t.Fatalf("unable to create profile: %v", err)
+				}
+				profiles = append(profiles, prfl)
+			}
+
+			// Run deschedule and balance plugins for all profiles
+			for _, prfl := range profiles {
+				prfl.RunDeschedulePlugins(ctx, nodes)
+				prfl.RunBalancePlugins(ctx, nodes)
+			}
+
+			// Verify creation, deschedule, and balance IDs all match
+			for _, profileCfg := range test.profiles {
+				verifyInstanceIDsMatch(
+					t,
+					profileCfg.profileInstanceID,
+					profileCfg.pluginNames,
+					profileCreationIDs[profileCfg.profileInstanceID],
+					profileDescheduleIDs[profileCfg.profileInstanceID],
+					profileBalanceIDs[profileCfg.profileInstanceID],
+				)
+			}
+
+			// Verify all plugins were invoked and have correct instance IDs
+			allInstanceIDs := sets.New[string]()
+			for _, profileCfg := range test.profiles {
+				profileInstanceIDs := verifyInstanceIDFormat(
+					t,
+					profileCfg.profileInstanceID,
+					profileCfg.pluginNames,
+					profileDescheduleIDs[profileCfg.profileInstanceID],
+				)
+				allInstanceIDs = allInstanceIDs.Union(profileInstanceIDs)
+			}
+
+			// Verify all instance IDs are unique across all profiles
+			totalExpectedPlugins := 0
+			for _, profileCfg := range test.profiles {
+				totalExpectedPlugins += len(profileCfg.pluginNames)
+			}
+			if allInstanceIDs.Len() != totalExpectedPlugins {
+				t.Errorf("Expected %d unique instance IDs across all profiles, got %d", totalExpectedPlugins, allInstanceIDs.Len())
+			}
+		})
+	}
+}

pkg/framework/types/types.go

@@ -41,6 +41,9 @@ type Handle interface {
 	GetPodsAssignedToNodeFunc() podutil.GetPodsAssignedToNodeFunc
 	SharedInformerFactory() informers.SharedInformerFactory
 	MetricsCollector() *metricscollector.MetricsCollector
+	// PluginInstanceID returns a unique identifier for this plugin instance.
+	// The ID is unique across all plugin instances in a configuration.
+	PluginInstanceID() string
 }
 
 // Evictor defines an interface for filtering and evicting pods

test/test_utils.go

@@ -43,6 +43,10 @@ import (
 // BuildTestPod creates a test pod with given parameters.
 func BuildTestPod(name string, cpu, memory int64, nodeName string, apply func(*v1.Pod)) *v1.Pod {
 	pod := &v1.Pod{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "v1",
+			Kind:       "Pod",
+		},
 		ObjectMeta: metav1.ObjectMeta{
 			Namespace: "default",
 			Name:      name,
@@ -76,6 +80,10 @@ func BuildTestPod(name string, cpu, memory int64, nodeName string, apply func(*v
 func BuildTestPDB(name, appLabel string) *policyv1.PodDisruptionBudget {
 	maxUnavailable := intstr.FromInt32(1)
 	pdb := &policyv1.PodDisruptionBudget{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "policy/v1",
+			Kind:       "PodDisruptionBudget",
+		},
 		ObjectMeta: metav1.ObjectMeta{
 			Namespace: "default",
 			Name:      name,
@@ -94,6 +102,10 @@ func BuildTestPDB(name, appLabel string) *policyv1.PodDisruptionBudget {
 
 func BuildTestPVC(name, storageClass string) *v1.PersistentVolumeClaim {
 	pvc := &v1.PersistentVolumeClaim{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "v1",
+			Kind:       "PersistentVolumeClaim",
+		},
 		ObjectMeta: metav1.ObjectMeta{
 			Namespace: "default",
 			Name:      name,
@@ -114,6 +126,10 @@ func BuildTestPVC(name, storageClass string) *v1.PersistentVolumeClaim {
 // BuildPodMetrics creates a test podmetrics with given parameters.
 func BuildPodMetrics(name string, millicpu, mem int64) *v1beta1.PodMetrics {
 	return &v1beta1.PodMetrics{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "metrics.k8s.io/v1beta1",
+			Kind:       "PodMetrics",
+		},
 		ObjectMeta: metav1.ObjectMeta{
 			Name:      name,
 			Namespace: "default",
@@ -171,6 +187,10 @@ func GetDaemonSetOwnerRefList() []metav1.OwnerReference {
 // BuildTestNode creates a node with specified capacity.
 func BuildTestNode(name string, millicpu, mem, pods int64, apply func(*v1.Node)) *v1.Node {
 	node := &v1.Node{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "v1",
+			Kind:       "Node",
+		},
 		ObjectMeta: metav1.ObjectMeta{
 			Name:     name,
 			SelfLink: fmt.Sprintf("/api/v1/nodes/%s", name),
@@ -201,6 +221,10 @@ func BuildTestNode(name string, millicpu, mem, pods int64, apply func(*v1.Node))
 
 func BuildNodeMetrics(name string, millicpu, mem int64) *v1beta1.NodeMetrics {
 	return &v1beta1.NodeMetrics{
+		TypeMeta: metav1.TypeMeta{
+			APIVersion: "metrics.k8s.io/v1beta1",
+			Kind:       "NodeMetrics",
+		},
 		ObjectMeta: metav1.ObjectMeta{
 			Name: name,
 		},