scheduler_perf: fix namespace deletion

Merely deleting the namespace is not enough:
- Workloads might rely on the garbage collector to get rid of obsolete objects,
  so we should run it to be on the safe side.
- Pods must be force-deleted because kubelet is not running.
- Finally, the namespace controller is needed to get rid of
  deleted namespaces.

test/integration/util/util.go

@@ -36,17 +36,22 @@ import (
 	"k8s.io/client-go/informers"
 	clientset "k8s.io/client-go/kubernetes"
 	corelisters "k8s.io/client-go/listers/core/v1"
+	"k8s.io/client-go/metadata"
+	"k8s.io/client-go/metadata/metadatainformer"
 	restclient "k8s.io/client-go/rest"
 	"k8s.io/client-go/restmapper"
 	"k8s.io/client-go/scale"
 	"k8s.io/client-go/tools/cache"
 	"k8s.io/client-go/tools/events"
 	pvutil "k8s.io/component-helpers/storage/volume"
+	"k8s.io/controller-manager/pkg/informerfactory"
 	"k8s.io/klog/v2"
 	"k8s.io/kube-scheduler/config/v1beta3"
 	"k8s.io/kubernetes/cmd/kube-apiserver/app/options"
 	podutil "k8s.io/kubernetes/pkg/api/v1/pod"
 	"k8s.io/kubernetes/pkg/controller/disruption"
+	"k8s.io/kubernetes/pkg/controller/garbagecollector"
+	"k8s.io/kubernetes/pkg/controller/namespace"
 	"k8s.io/kubernetes/pkg/controller/resourceclaim"
 	"k8s.io/kubernetes/pkg/controlplane"
 	"k8s.io/kubernetes/pkg/scheduler"
@@ -162,6 +167,67 @@ func StartFakePVController(ctx context.Context, clientSet clientset.Interface, i
 	})
 }
 
+// CreateGCController creates a garbage controller and returns a run function
+// for it. The informer factory needs to be started before invoking that
+// function.
+func CreateGCController(ctx context.Context, tb testing.TB, restConfig restclient.Config, informerSet informers.SharedInformerFactory) func() {
+	restclient.AddUserAgent(&restConfig, "gc-controller")
+	clientSet := clientset.NewForConfigOrDie(&restConfig)
+	metadataClient, err := metadata.NewForConfig(&restConfig)
+	if err != nil {
+		tb.Fatalf("Failed to create metadataClient: %v", err)
+	}
+	restMapper := restmapper.NewDeferredDiscoveryRESTMapper(cacheddiscovery.NewMemCacheClient(clientSet.Discovery()))
+	restMapper.Reset()
+	metadataInformers := metadatainformer.NewSharedInformerFactory(metadataClient, 0)
+	alwaysStarted := make(chan struct{})
+	close(alwaysStarted)
+	gc, err := garbagecollector.NewGarbageCollector(
+		clientSet,
+		metadataClient,
+		restMapper,
+		garbagecollector.DefaultIgnoredResources(),
+		informerfactory.NewInformerFactory(informerSet, metadataInformers),
+		alwaysStarted,
+	)
+	if err != nil {
+		tb.Fatalf("Failed creating garbage collector")
+	}
+	startGC := func() {
+		syncPeriod := 5 * time.Second
+		go wait.Until(func() {
+			restMapper.Reset()
+		}, syncPeriod, ctx.Done())
+		go gc.Run(ctx, 1)
+		go gc.Sync(ctx, clientSet.Discovery(), syncPeriod)
+	}
+	return startGC
+}
+
+// CreateNamespaceController creates a namespace controller and returns a run
+// function for it. The informer factory needs to be started before invoking
+// that function.
+func CreateNamespaceController(ctx context.Context, tb testing.TB, restConfig restclient.Config, informerSet informers.SharedInformerFactory) func() {
+	restclient.AddUserAgent(&restConfig, "namespace-controller")
+	clientSet := clientset.NewForConfigOrDie(&restConfig)
+	metadataClient, err := metadata.NewForConfig(&restConfig)
+	if err != nil {
+		tb.Fatalf("Failed to create metadataClient: %v", err)
+	}
+	discoverResourcesFn := clientSet.Discovery().ServerPreferredNamespacedResources
+	controller := namespace.NewNamespaceController(
+		ctx,
+		clientSet,
+		metadataClient,
+		discoverResourcesFn,
+		informerSet.Core().V1().Namespaces(),
+		10*time.Hour,
+		v1.FinalizerKubernetes)
+	return func() {
+		go controller.Run(ctx, 5)
+	}
+}
+
 // TestContext store necessary context info
 type TestContext struct {
 	NS                 *v1.Namespace