func ReaperFor(kind unversioned.GroupKind, c client.Interface) (Reaper, error) {
	switch kind {
	case api.Kind("ReplicationController"):
		return &ReplicationControllerReaper{c, Interval, Timeout}, nil

	case extensions.Kind("ReplicaSet"):
		return &ReplicaSetReaper{c, Interval, Timeout}, nil

	case extensions.Kind("DaemonSet"):
		return &DaemonSetReaper{c, Interval, Timeout}, nil

	case api.Kind("Pod"):
		return &PodReaper{c}, nil

	case api.Kind("Service"):
		return &ServiceReaper{c}, nil

	case extensions.Kind("Job"), batch.Kind("Job"):
		return &JobReaper{c, Interval, Timeout}, nil

	case extensions.Kind("Deployment"):
		return &DeploymentReaper{c, Interval, Timeout}, nil

	}
	return nil, &NoSuchReaperError{kind}
}

func cleanupDensityTest(dtc DensityTestConfig) {
	defer GinkgoRecover()
	By("Deleting created Collections")
	// We explicitly delete all pods to have API calls necessary for deletion accounted in metrics.
	for i := range dtc.Configs {
		name := dtc.Configs[i].GetName()
		namespace := dtc.Configs[i].GetNamespace()
		kind := dtc.Configs[i].GetKind()
		// TODO: Remove Deployment guard once GC is implemented for Deployments.
		if framework.TestContext.GarbageCollectorEnabled && kind != extensions.Kind("Deployment") {
			By(fmt.Sprintf("Cleaning up only the %v, garbage collector will clean up the pods", kind))
			err := framework.DeleteResourceAndWaitForGC(dtc.ClientSet, kind, namespace, name)
			framework.ExpectNoError(err)
		} else {
			By(fmt.Sprintf("Cleaning up the %v and pods", kind))
			err := framework.DeleteResourceAndPods(dtc.ClientSet, dtc.InternalClientset, kind, namespace, name)
			framework.ExpectNoError(err)
		}
	}

	// Delete all secrets
	for i := range dtc.SecretConfigs {
		dtc.SecretConfigs[i].Stop()
	}

	for i := range dtc.DaemonConfigs {
		framework.ExpectNoError(framework.DeleteResourceAndPods(
			dtc.ClientSet,
			dtc.InternalClientset,
			extensions.Kind("DaemonSet"),
			dtc.DaemonConfigs[i].Namespace,
			dtc.DaemonConfigs[i].Name,
		))
	}
}

func generateConfigsForGroup(
	nss []*v1.Namespace, groupName string, size, count int, image string, command []string, kind schema.GroupKind) []testutils.RunObjectConfig {
	configs := make([]testutils.RunObjectConfig, 0, count)
	for i := 1; i <= count; i++ {
		baseConfig := &testutils.RCConfig{
			Client:         nil, // this will be overwritten later
			InternalClient: nil, // this will be overwritten later
			Name:           groupName + "-" + strconv.Itoa(i),
			Namespace:      nss[i%len(nss)].Name,
			Timeout:        10 * time.Minute,
			Image:          image,
			Command:        command,
			Replicas:       size,
			CpuRequest:     10,       // 0.01 core
			MemRequest:     26214400, // 25MB
		}
		var config testutils.RunObjectConfig
		switch kind {
		case api.Kind("ReplicationController"):
			config = baseConfig
		case extensions.Kind("ReplicaSet"):
			config = &testutils.ReplicaSetConfig{RCConfig: *baseConfig}
		case extensions.Kind("Deployment"):
			config = &testutils.DeploymentConfig{RCConfig: *baseConfig}
		default:
			framework.Failf("Unsupported kind for config creation: %v", kind)
		}
		configs = append(configs, config)
	}
	return configs
}

func ReaperFor(kind schema.GroupKind, c internalclientset.Interface) (Reaper, error) {
	switch kind {
	case api.Kind("ReplicationController"):
		return &ReplicationControllerReaper{c.Core(), Interval, Timeout}, nil

	case extensions.Kind("ReplicaSet"):
		return &ReplicaSetReaper{c.Extensions(), Interval, Timeout}, nil

	case extensions.Kind("DaemonSet"):
		return &DaemonSetReaper{c.Extensions(), Interval, Timeout}, nil

	case api.Kind("Pod"):
		return &PodReaper{c.Core()}, nil

	case api.Kind("Service"):
		return &ServiceReaper{c.Core()}, nil

	case extensions.Kind("Job"), batch.Kind("Job"):
		return &JobReaper{c.Batch(), c.Core(), Interval, Timeout}, nil

	case apps.Kind("StatefulSet"):
		return &StatefulSetReaper{c.Apps(), c.Core(), Interval, Timeout}, nil

	case extensions.Kind("Deployment"):
		return &DeploymentReaper{c.Extensions(), c.Extensions(), Interval, Timeout}, nil

	}
	return nil, &NoSuchReaperError{kind}
}

func generateConfigsForGroup(
	nss []*v1.Namespace,
	groupName string,
	size, count int,
	image string,
	command []string,
	kind schema.GroupKind,
	secretsPerPod int,
) ([]testutils.RunObjectConfig, []*testutils.SecretConfig) {
	configs := make([]testutils.RunObjectConfig, 0, count)
	secretConfigs := make([]*testutils.SecretConfig, 0, count*secretsPerPod)
	for i := 1; i <= count; i++ {
		namespace := nss[i%len(nss)].Name
		secretNames := make([]string, 0, secretsPerPod)

		for j := 0; j < secretsPerPod; j++ {
			secretName := fmt.Sprintf("%v-%v-secret-%v", groupName, i, j)
			secretConfigs = append(secretConfigs, &testutils.SecretConfig{
				Content:   map[string]string{"foo": "bar"},
				Client:    nil, // this will be overwritten later
				Name:      secretName,
				Namespace: namespace,
				LogFunc:   framework.Logf,
			})
			secretNames = append(secretNames, secretName)
		}

		baseConfig := &testutils.RCConfig{
			Client:         nil, // this will be overwritten later
			InternalClient: nil, // this will be overwritten later
			Name:           groupName + "-" + strconv.Itoa(i),
			Namespace:      namespace,
			Timeout:        10 * time.Minute,
			Image:          image,
			Command:        command,
			Replicas:       size,
			CpuRequest:     10,       // 0.01 core
			MemRequest:     26214400, // 25MB
			SecretNames:    secretNames,
		}

		var config testutils.RunObjectConfig
		switch kind {
		case api.Kind("ReplicationController"):
			config = baseConfig
		case extensions.Kind("ReplicaSet"):
			config = &testutils.ReplicaSetConfig{RCConfig: *baseConfig}
		case extensions.Kind("Deployment"):
			config = &testutils.DeploymentConfig{RCConfig: *baseConfig}
		case batch.Kind("Job"):
			config = &testutils.JobConfig{RCConfig: *baseConfig}
		default:
			framework.Failf("Unsupported kind for config creation: %v", kind)
		}
		configs = append(configs, config)
	}
	return configs, secretConfigs
}

func ScalerFor(kind unversioned.GroupKind, c client.Interface) (Scaler, error) {
	switch kind {
	case api.Kind("ReplicationController"):
		return &ReplicationControllerScaler{c}, nil
	case extensions.Kind("Job"):
		return &JobScaler{c.Extensions()}, nil
	case extensions.Kind("Deployment"):
		return &DeploymentScaler{c.Extensions()}, nil
	}
	return nil, fmt.Errorf("no scaler has been implemented for %q", kind)
}

func ScalerFor(kind unversioned.GroupKind, c client.Interface) (Scaler, error) {
	switch kind {
	case api.Kind("ReplicationController"):
		return &ReplicationControllerScaler{c}, nil
	case extensions.Kind("ReplicaSet"):
		return &ReplicaSetScaler{c.Extensions()}, nil
	case extensions.Kind("Job"):
		return &JobScaler{c.Extensions()}, nil
		// TODO(madhusudancs): Fix this when Scale group issues are resolved (see issue #18528).
		// case extensions.Kind("Deployment"):
		// 	return &DeploymentScaler{c.Extensions()}, nil
	}
	return nil, fmt.Errorf("no scaler has been implemented for %q", kind)
}

func ScalerFor(kind schema.GroupKind, c internalclientset.Interface) (Scaler, error) {
	switch kind {
	case api.Kind("ReplicationController"):
		return &ReplicationControllerScaler{c.Core()}, nil
	case extensions.Kind("ReplicaSet"):
		return &ReplicaSetScaler{c.Extensions()}, nil
	case extensions.Kind("Job"), batch.Kind("Job"):
		return &JobScaler{c.Batch()}, nil // Either kind of job can be scaled with Batch interface.
	case apps.Kind("StatefulSet"):
		return &StatefulSetScaler{c.Apps()}, nil
	case extensions.Kind("Deployment"):
		return &DeploymentScaler{c.Extensions()}, nil
	}
	return nil, fmt.Errorf("no scaler has been implemented for %q", kind)
}

// Update scales the DeploymentConfig for the given Scale subresource, returning the updated Scale.
func (r *ScaleREST) Update(ctx kapi.Context, name string, objInfo rest.UpdatedObjectInfo) (runtime.Object, bool, error) {
	deploymentConfig, err := r.registry.GetDeploymentConfig(ctx, name)
	if err != nil {
		return nil, false, errors.NewNotFound(extensions.Resource("scale"), name)
	}

	old := api.ScaleFromConfig(deploymentConfig)
	obj, err := objInfo.UpdatedObject(ctx, old)
	if err != nil {
		return nil, false, err
	}

	scale, ok := obj.(*extensions.Scale)
	if !ok {
		return nil, false, errors.NewBadRequest(fmt.Sprintf("wrong object passed to Scale update: %v", obj))
	}

	if errs := extvalidation.ValidateScale(scale); len(errs) > 0 {
		return nil, false, errors.NewInvalid(extensions.Kind("Scale"), scale.Name, errs)
	}

	deploymentConfig.Spec.Replicas = scale.Spec.Replicas
	if err := r.registry.UpdateDeploymentConfig(ctx, deploymentConfig); err != nil {
		return nil, false, err
	}

	return scale, false, nil
}

func StatusViewerFor(kind unversioned.GroupKind, c client.Interface) (StatusViewer, error) {
	switch kind {
	case extensions.Kind("Deployment"):
		return &DeploymentStatusViewer{c.Extensions()}, nil
	}
	return nil, fmt.Errorf("no status viewer has been implemented for %v", kind)
}

func (r *ScaleREST) Update(ctx api.Context, name string, objInfo rest.UpdatedObjectInfo) (runtime.Object, bool, error) {
	rc, err := (*r.registry).GetController(ctx, name)
	if err != nil {
		return nil, false, errors.NewNotFound(extensions.Resource("replicationcontrollers/scale"), name)
	}
	oldScale := scaleFromRC(rc)

	obj, err := objInfo.UpdatedObject(ctx, oldScale)

	if obj == nil {
		return nil, false, errors.NewBadRequest(fmt.Sprintf("nil update passed to Scale"))
	}
	scale, ok := obj.(*extensions.Scale)
	if !ok {
		return nil, false, errors.NewBadRequest(fmt.Sprintf("wrong object passed to Scale update: %v", obj))
	}

	if errs := extvalidation.ValidateScale(scale); len(errs) > 0 {
		return nil, false, errors.NewInvalid(extensions.Kind("Scale"), scale.Name, errs)
	}

	rc.Spec.Replicas = scale.Spec.Replicas
	rc.ResourceVersion = scale.ResourceVersion
	rc, err = (*r.registry).UpdateController(ctx, rc)
	if err != nil {
		return nil, false, errors.NewConflict(extensions.Resource("replicationcontrollers/scale"), scale.Name, err)
	}
	return scaleFromRC(rc), false, nil
}

func (r *ScaleREST) Update(ctx api.Context, obj runtime.Object) (runtime.Object, bool, error) {
	if obj == nil {
		return nil, false, errors.NewBadRequest(fmt.Sprintf("nil update passed to Scale"))
	}
	scale, ok := obj.(*extensions.Scale)
	if !ok {
		return nil, false, errors.NewBadRequest(fmt.Sprintf("expected input object type to be Scale, but %T", obj))
	}

	if errs := extvalidation.ValidateScale(scale); len(errs) > 0 {
		return nil, false, errors.NewInvalid(extensions.Kind("Scale"), scale.Name, errs)
	}

	deployment, err := r.registry.GetDeployment(ctx, scale.Name)
	if err != nil {
		return nil, false, errors.NewNotFound(extensions.Resource("deployments/scale"), scale.Name)
	}
	deployment.Spec.Replicas = scale.Spec.Replicas
	deployment.ResourceVersion = scale.ResourceVersion
	deployment, err = r.registry.UpdateDeployment(ctx, deployment)
	if err != nil {
		return nil, false, err
	}
	newScale, err := scaleFromDeployment(deployment)
	if err != nil {
		return nil, false, errors.NewBadRequest(fmt.Sprintf("%v", err))
	}
	return newScale, false, nil
}

func RollbackerFor(kind unversioned.GroupKind, c client.Interface) (Rollbacker, error) {
	switch kind {
	case extensions.Kind("Deployment"):
		return &DeploymentRollbacker{c}, nil
	}
	return nil, fmt.Errorf("no rollbacker has been implemented for %q", kind)
}

func (r *ScaleREST) Update(ctx api.Context, obj runtime.Object) (runtime.Object, bool, error) {
	if obj == nil {
		return nil, false, errors.NewBadRequest(fmt.Sprintf("nil update passed to Scale"))
	}
	scale, ok := obj.(*extensions.Scale)
	if !ok {
		return nil, false, errors.NewBadRequest(fmt.Sprintf("wrong object passed to Scale update: %v", obj))
	}

	if errs := extvalidation.ValidateScale(scale); len(errs) > 0 {
		return nil, false, errors.NewInvalid(extensions.Kind("Scale"), scale.Name, errs)
	}

	rs, err := r.registry.GetReplicaSet(ctx, scale.Name)
	if err != nil {
		return nil, false, errors.NewNotFound(extensions.Resource("replicasets/scale"), scale.Name)
	}
	rs.Spec.Replicas = scale.Spec.Replicas
	rs.ResourceVersion = scale.ResourceVersion
	rs, err = r.registry.UpdateReplicaSet(ctx, rs)
	if err != nil {
		return nil, false, err
	}
	newScale, err := scaleFromReplicaSet(rs)
	if err != nil {
		return nil, false, errors.NewBadRequest(fmt.Sprintf("%v", err))
	}
	return newScale, false, err
}

func HistoryViewerFor(kind unversioned.GroupKind, c clientset.Interface) (HistoryViewer, error) {
	switch kind {
	case extensions.Kind("Deployment"):
		return &DeploymentHistoryViewer{c}, nil
	}
	return nil, fmt.Errorf("no history viewer has been implemented for %q", kind)
}

func (reaper *DeploymentReaper) Stop(namespace, name string, timeout time.Duration, gracePeriod *api.DeleteOptions) error {
	deployments := reaper.Extensions().Deployments(namespace)
	replicaSets := reaper.Extensions().ReplicaSets(namespace)
	rsReaper, _ := ReaperFor(extensions.Kind("ReplicaSet"), reaper)

	deployment, err := reaper.updateDeploymentWithRetries(namespace, name, func(d *extensions.Deployment) {
		// set deployment's history and scale to 0
		// TODO replace with patch when available: https://github.com/kubernetes/kubernetes/issues/20527
		d.Spec.RevisionHistoryLimit = util.Int32Ptr(0)
		d.Spec.Replicas = 0
		d.Spec.Paused = true
	})
	if err != nil {
		return err
	}

	// Use observedGeneration to determine if the deployment controller noticed the pause.
	if err := deploymentutil.WaitForObservedDeployment(func() (*extensions.Deployment, error) {
		return deployments.Get(name)
	}, deployment.Generation, 1*time.Second, 1*time.Minute); err != nil {
		return err
	}

	// Stop all replica sets.
	selector, err := unversioned.LabelSelectorAsSelector(deployment.Spec.Selector)
	if err != nil {
		return err
	}

	options := api.ListOptions{LabelSelector: selector}
	rsList, err := replicaSets.List(options)
	if err != nil {
		return err
	}
	errList := []error{}
	for _, rc := range rsList.Items {
		if err := rsReaper.Stop(rc.Namespace, rc.Name, timeout, gracePeriod); err != nil {
			scaleGetErr, ok := err.(*ScaleError)
			if errors.IsNotFound(err) || (ok && errors.IsNotFound(scaleGetErr.ActualError)) {
				continue
			}
			errList = append(errList, err)
		}
	}
	if len(errList) > 0 {
		return utilerrors.NewAggregate(errList)
	}

	// Delete deployment at the end.
	// Note: We delete deployment at the end so that if removing RSs fails, we at least have the deployment to retry.
	return deployments.Delete(name, nil)
}

func (r *RollbackREST) Create(ctx api.Context, obj runtime.Object) (out runtime.Object, err error) {
	rollback, ok := obj.(*extensions.DeploymentRollback)
	if !ok {
		return nil, fmt.Errorf("expected input object type to be DeploymentRollback, but %T", obj)
	}

	if errs := extvalidation.ValidateDeploymentRollback(rollback); len(errs) != 0 {
		return nil, errors.NewInvalid(extensions.Kind("DeploymentRollback"), rollback.Name, errs)
	}

	// Update the Deployment with information in DeploymentRollback to trigger rollback
	err = r.rollbackDeployment(ctx, rollback.Name, &rollback.RollbackTo, rollback.UpdatedAnnotations)
	return
}

func deleteResource(wg *sync.WaitGroup, config testutils.RunObjectConfig, deletingTime time.Duration) {
	defer GinkgoRecover()
	defer wg.Done()

	sleepUpTo(deletingTime)
	if framework.TestContext.GarbageCollectorEnabled && config.GetKind() != extensions.Kind("Deployment") {
		framework.ExpectNoError(framework.DeleteResourceAndWaitForGC(
			config.GetClient(), config.GetKind(), config.GetNamespace(), config.GetName()),
			fmt.Sprintf("deleting %v %s", config.GetKind(), config.GetName()))
	} else {
		framework.ExpectNoError(framework.DeleteResourceAndPods(
			config.GetClient(), config.GetInternalClient(), config.GetKind(), config.GetNamespace(), config.GetName()),
			fmt.Sprintf("deleting %v %s", config.GetKind(), config.GetName()))
	}
}

// Update scales the DeploymentConfig for the given Scale subresource, returning the updated Scale.
func (r *ScaleREST) Update(ctx kapi.Context, obj runtime.Object) (runtime.Object, bool, error) {
	if obj == nil {
		return nil, false, errors.NewBadRequest(fmt.Sprintf("nil update passed to Scale"))
	}
	scale, ok := obj.(*extensions.Scale)
	if !ok {
		return nil, false, errors.NewBadRequest(fmt.Sprintf("wrong object passed to Scale update: %v", obj))
	}

	if errs := extvalidation.ValidateScale(scale); len(errs) > 0 {
		return nil, false, errors.NewInvalid(extensions.Kind("Scale"), scale.Name, errs)
	}

	deploymentConfig, err := r.registry.GetDeploymentConfig(ctx, scale.Name)
	if err != nil {
		return nil, false, errors.NewNotFound(extensions.Resource("scale"), scale.Name)
	}

	scaleRet := &extensions.Scale{
		ObjectMeta: kapi.ObjectMeta{
			Name:              deploymentConfig.Name,
			Namespace:         deploymentConfig.Namespace,
			CreationTimestamp: deploymentConfig.CreationTimestamp,
		},
		Spec: extensions.ScaleSpec{
			Replicas: scale.Spec.Replicas,
		},
		Status: extensions.ScaleStatus{
			Selector: &unversioned.LabelSelector{MatchLabels: deploymentConfig.Spec.Selector},
		},
	}

	// TODO(directxman12): this is going to be a bit out of sync, since we are calculating it
	// here and not as part of the deploymentconfig loop -- is there a better way of doing it?
	totalReplicas, err := r.replicasForDeploymentConfig(deploymentConfig.Namespace, deploymentConfig.Name)
	if err != nil {
		return nil, false, err
	}

	oldReplicas := deploymentConfig.Spec.Replicas
	deploymentConfig.Spec.Replicas = scale.Spec.Replicas
	if err := r.registry.UpdateDeploymentConfig(ctx, deploymentConfig); err != nil {
		return nil, false, err
	}
	scaleRet.Status.Replicas = totalReplicas + (scale.Spec.Replicas - oldReplicas)

	return scaleRet, false, nil
}

func (reaper *JobReaper) Stop(namespace, name string, timeout time.Duration, gracePeriod *api.DeleteOptions) error {
	jobs := reaper.Extensions().Jobs(namespace)
	pods := reaper.Pods(namespace)
	scaler, err := ScalerFor(extensions.Kind("Job"), *reaper)
	if err != nil {
		return err
	}
	job, err := jobs.Get(name)
	if err != nil {
		return err
	}
	if timeout == 0 {
		// we will never have more active pods than job.Spec.Parallelism
		parallelism := *job.Spec.Parallelism
		timeout = Timeout + time.Duration(10*parallelism)*time.Second
	}

	// TODO: handle overlapping jobs
	retry := NewRetryParams(reaper.pollInterval, reaper.timeout)
	waitForJobs := NewRetryParams(reaper.pollInterval, timeout)
	if err = scaler.Scale(namespace, name, 0, nil, retry, waitForJobs); err != nil {
		return err
	}
	// at this point only dead pods are left, that should be removed
	selector, _ := extensions.LabelSelectorAsSelector(job.Spec.Selector)
	options := api.ListOptions{LabelSelector: selector}
	podList, err := pods.List(options)
	if err != nil {
		return err
	}
	errList := []error{}
	for _, pod := range podList.Items {
		if err := pods.Delete(pod.Name, gracePeriod); err != nil {
			// ignores the error when the pod isn't found
			if !errors.IsNotFound(err) {
				errList = append(errList, err)
			}
		}
	}
	if len(errList) > 0 {
		return utilerrors.NewAggregate(errList)
	}
	// once we have all the pods removed we can safely remove the job itself
	if err := jobs.Delete(name, gracePeriod); err != nil {
		return err
	}
	return nil
}