factory.go

/*
Copyright 2014 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 factory can set up a scheduler. This code is here instead of
// cmd/scheduler for both testability and reuse.
package factory

import (
	"fmt"
	"os"
	"os/signal"
	"reflect"
	"time"

	"github.com/golang/glog"

	"k8s.io/api/core/v1"
	storagev1 "k8s.io/api/storage/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/fields"
	"k8s.io/apimachinery/pkg/labels"
	"k8s.io/apimachinery/pkg/runtime/schema"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/apimachinery/pkg/util/runtime"
	"k8s.io/apimachinery/pkg/util/sets"
	utilfeature "k8s.io/apiserver/pkg/util/feature"
	appsinformers "k8s.io/client-go/informers/apps/v1"
	coreinformers "k8s.io/client-go/informers/core/v1"
	policyinformers "k8s.io/client-go/informers/policy/v1beta1"
	storageinformers "k8s.io/client-go/informers/storage/v1"
	clientset "k8s.io/client-go/kubernetes"
	appslisters "k8s.io/client-go/listers/apps/v1"
	corelisters "k8s.io/client-go/listers/core/v1"
	policylisters "k8s.io/client-go/listers/policy/v1beta1"
	storagelisters "k8s.io/client-go/listers/storage/v1"
	"k8s.io/client-go/tools/cache"
	"k8s.io/client-go/tools/record"
	podutil "k8s.io/kubernetes/pkg/api/v1/pod"
	"k8s.io/kubernetes/pkg/apis/core/helper"
	"k8s.io/kubernetes/pkg/features"
	kubeletapis "k8s.io/kubernetes/pkg/kubelet/apis"
	"k8s.io/kubernetes/pkg/scheduler/algorithm"
	"k8s.io/kubernetes/pkg/scheduler/algorithm/predicates"
	schedulerapi "k8s.io/kubernetes/pkg/scheduler/api"
	"k8s.io/kubernetes/pkg/scheduler/api/validation"
	"k8s.io/kubernetes/pkg/scheduler/core"
	"k8s.io/kubernetes/pkg/scheduler/core/equivalence"
	schedulerinternalcache "k8s.io/kubernetes/pkg/scheduler/internal/cache"
	cachecomparer "k8s.io/kubernetes/pkg/scheduler/internal/cache/comparer"
	internalqueue "k8s.io/kubernetes/pkg/scheduler/internal/queue"
	"k8s.io/kubernetes/pkg/scheduler/util"
	"k8s.io/kubernetes/pkg/scheduler/volumebinder"
)

const (
	initialGetBackoff = 100 * time.Millisecond
	maximalGetBackoff = time.Minute
)

var (
	serviceAffinitySet            = sets.NewString(predicates.CheckServiceAffinityPred)
	matchInterPodAffinitySet      = sets.NewString(predicates.MatchInterPodAffinityPred)
	generalPredicatesSets         = sets.NewString(predicates.GeneralPred)
	noDiskConflictSet             = sets.NewString(predicates.NoDiskConflictPred)
	maxPDVolumeCountPredicateKeys = []string{predicates.MaxGCEPDVolumeCountPred, predicates.MaxAzureDiskVolumeCountPred, predicates.MaxEBSVolumeCountPred}
)

// Binder knows how to write a binding.
type Binder interface {
	Bind(binding *v1.Binding) error
}

// PodConditionUpdater updates the condition of a pod based on the passed
// PodCondition
type PodConditionUpdater interface {
	Update(pod *v1.Pod, podCondition *v1.PodCondition) error
}

// Config is an implementation of the Scheduler's configured input data.
// TODO over time we should make this struct a hidden implementation detail of the scheduler.
type Config struct {
	// It is expected that changes made via SchedulerCache will be observed
	// by NodeLister and Algorithm.
	SchedulerCache schedulerinternalcache.Cache
	// Ecache is used for optimistically invalid affected cache items after
	// successfully binding a pod
	Ecache     *equivalence.Cache
	NodeLister algorithm.NodeLister
	Algorithm  algorithm.ScheduleAlgorithm
	GetBinder  func(pod *v1.Pod) Binder
	// PodConditionUpdater is used only in case of scheduling errors. If we succeed
	// with scheduling, PodScheduled condition will be updated in apiserver in /bind
	// handler so that binding and setting PodCondition it is atomic.
	PodConditionUpdater PodConditionUpdater
	// PodPreemptor is used to evict pods and update pod annotations.
	PodPreemptor PodPreemptor

	// NextPod should be a function that blocks until the next pod
	// is available. We don't use a channel for this, because scheduling
	// a pod may take some amount of time and we don't want pods to get
	// stale while they sit in a channel.
	NextPod func() *v1.Pod

	// WaitForCacheSync waits for scheduler cache to populate.
	// It returns true if it was successful, false if the controller should shutdown.
	WaitForCacheSync func() bool

	// Error is called if there is an error. It is passed the pod in
	// question, and the error
	Error func(*v1.Pod, error)

	// Recorder is the EventRecorder to use
	Recorder record.EventRecorder

	// Close this to shut down the scheduler.
	StopEverything chan struct{}

	// VolumeBinder handles PVC/PV binding for the pod.
	VolumeBinder *volumebinder.VolumeBinder

	// Disable pod preemption or not.
	DisablePreemption bool
}

// PodPreemptor has methods needed to delete a pod and to update
// annotations of the preemptor pod.
type PodPreemptor interface {
	GetUpdatedPod(pod *v1.Pod) (*v1.Pod, error)
	DeletePod(pod *v1.Pod) error
	SetNominatedNodeName(pod *v1.Pod, nominatedNode string) error
	RemoveNominatedNodeName(pod *v1.Pod) error
}

// Configurator defines I/O, caching, and other functionality needed to
// construct a new scheduler. An implementation of this can be seen in
// factory.go.
type Configurator interface {
	// Exposed for testing
	GetHardPodAffinitySymmetricWeight() int32
	// Exposed for testing
	MakeDefaultErrorFunc(backoff *util.PodBackoff, podQueue internalqueue.SchedulingQueue) func(pod *v1.Pod, err error)

	// Predicate related accessors to be exposed for use by k8s.io/autoscaler/cluster-autoscaler
	GetPredicateMetadataProducer() (algorithm.PredicateMetadataProducer, error)
	GetPredicates(predicateKeys sets.String) (map[string]algorithm.FitPredicate, error)

	// Needs to be exposed for things like integration tests where we want to make fake nodes.
	GetNodeLister() corelisters.NodeLister
	// Exposed for testing
	GetClient() clientset.Interface
	// Exposed for testing
	GetScheduledPodLister() corelisters.PodLister

	Create() (*Config, error)
	CreateFromProvider(providerName string) (*Config, error)
	CreateFromConfig(policy schedulerapi.Policy) (*Config, error)
	CreateFromKeys(predicateKeys, priorityKeys sets.String, extenders []algorithm.SchedulerExtender) (*Config, error)
}

// configFactory is the default implementation of the scheduler.Configurator interface.
type configFactory struct {
	client clientset.Interface
	// queue for pods that need scheduling
	podQueue internalqueue.SchedulingQueue
	// a means to list all known scheduled pods.
	scheduledPodLister corelisters.PodLister
	// a means to list all known scheduled pods and pods assumed to have been scheduled.
	podLister algorithm.PodLister
	// a means to list all nodes
	nodeLister corelisters.NodeLister
	// a means to list all PersistentVolumes
	pVLister corelisters.PersistentVolumeLister
	// a means to list all PersistentVolumeClaims
	pVCLister corelisters.PersistentVolumeClaimLister
	// a means to list all services
	serviceLister corelisters.ServiceLister
	// a means to list all controllers
	controllerLister corelisters.ReplicationControllerLister
	// a means to list all replicasets
	replicaSetLister appslisters.ReplicaSetLister
	// a means to list all statefulsets
	statefulSetLister appslisters.StatefulSetLister
	// a means to list all PodDisruptionBudgets
	pdbLister policylisters.PodDisruptionBudgetLister
	// a means to list all StorageClasses
	storageClassLister storagelisters.StorageClassLister

	// Close this to stop all reflectors
	StopEverything chan struct{}

	scheduledPodsHasSynced cache.InformerSynced

	schedulerCache schedulerinternalcache.Cache

	// SchedulerName of a scheduler is used to select which pods will be
	// processed by this scheduler, based on pods's "spec.schedulerName".
	schedulerName string

	// RequiredDuringScheduling affinity is not symmetric, but there is an implicit PreferredDuringScheduling affinity rule
	// corresponding to every RequiredDuringScheduling affinity rule.
	// HardPodAffinitySymmetricWeight represents the weight of implicit PreferredDuringScheduling affinity rule, in the range 0-100.
	hardPodAffinitySymmetricWeight int32

	// Equivalence class cache
	equivalencePodCache *equivalence.Cache

	// Enable equivalence class cache
	enableEquivalenceClassCache bool

	// Handles volume binding decisions
	volumeBinder *volumebinder.VolumeBinder

	// Always check all predicates even if the middle of one predicate fails.
	alwaysCheckAllPredicates bool

	// Disable pod preemption or not.
	disablePreemption bool

	// percentageOfNodesToScore specifies percentage of all nodes to score in each scheduling cycle.
	percentageOfNodesToScore int32
}

// ConfigFactoryArgs is a set arguments passed to NewConfigFactory.
type ConfigFactoryArgs struct {
	SchedulerName                  string
	Client                         clientset.Interface
	NodeInformer                   coreinformers.NodeInformer
	PodInformer                    coreinformers.PodInformer
	PvInformer                     coreinformers.PersistentVolumeInformer
	PvcInformer                    coreinformers.PersistentVolumeClaimInformer
	ReplicationControllerInformer  coreinformers.ReplicationControllerInformer
	ReplicaSetInformer             appsinformers.ReplicaSetInformer
	StatefulSetInformer            appsinformers.StatefulSetInformer
	ServiceInformer                coreinformers.ServiceInformer
	PdbInformer                    policyinformers.PodDisruptionBudgetInformer
	StorageClassInformer           storageinformers.StorageClassInformer
	HardPodAffinitySymmetricWeight int32
	EnableEquivalenceClassCache    bool
	DisablePreemption              bool
	PercentageOfNodesToScore       int32
	BindTimeoutSeconds             int64
}

// NewConfigFactory initializes the default implementation of a Configurator. To encourage eventual privatization of the struct type, we only
// return the interface.
func NewConfigFactory(args *ConfigFactoryArgs) Configurator {
	stopEverything := make(chan struct{})
	schedulerCache := schedulerinternalcache.New(30*time.Second, stopEverything)

	// storageClassInformer is only enabled through VolumeScheduling feature gate
	var storageClassLister storagelisters.StorageClassLister
	if args.StorageClassInformer != nil {
		storageClassLister = args.StorageClassInformer.Lister()
	}
	c := &configFactory{
		client:                         args.Client,
		podLister:                      schedulerCache,
		podQueue:                       internalqueue.NewSchedulingQueue(),
		nodeLister:                     args.NodeInformer.Lister(),
		pVLister:                       args.PvInformer.Lister(),
		pVCLister:                      args.PvcInformer.Lister(),
		serviceLister:                  args.ServiceInformer.Lister(),
		controllerLister:               args.ReplicationControllerInformer.Lister(),
		replicaSetLister:               args.ReplicaSetInformer.Lister(),
		statefulSetLister:              args.StatefulSetInformer.Lister(),
		pdbLister:                      args.PdbInformer.Lister(),
		storageClassLister:             storageClassLister,
		schedulerCache:                 schedulerCache,
		StopEverything:                 stopEverything,
		schedulerName:                  args.SchedulerName,
		hardPodAffinitySymmetricWeight: args.HardPodAffinitySymmetricWeight,
		enableEquivalenceClassCache:    args.EnableEquivalenceClassCache,
		disablePreemption:              args.DisablePreemption,
		percentageOfNodesToScore:       args.PercentageOfNodesToScore,
	}

	c.scheduledPodsHasSynced = args.PodInformer.Informer().HasSynced
	// scheduled pod cache
	args.PodInformer.Informer().AddEventHandler(
		cache.FilteringResourceEventHandler{
			FilterFunc: func(obj interface{}) bool {
				switch t := obj.(type) {
				case *v1.Pod:
					return assignedPod(t)
				case cache.DeletedFinalStateUnknown:
					if pod, ok := t.Obj.(*v1.Pod); ok {
						return assignedPod(pod)
					}
					runtime.HandleError(fmt.Errorf("unable to convert object %T to *v1.Pod in %T", obj, c))
					return false
				default:
					runtime.HandleError(fmt.Errorf("unable to handle object in %T: %T", c, obj))
					return false
				}
			},
			Handler: cache.ResourceEventHandlerFuncs{
				AddFunc:    c.addPodToCache,
				UpdateFunc: c.updatePodInCache,
				DeleteFunc: c.deletePodFromCache,
			},
		},
	)
	// unscheduled pod queue
	args.PodInformer.Informer().AddEventHandler(
		cache.FilteringResourceEventHandler{
			FilterFunc: func(obj interface{}) bool {
				switch t := obj.(type) {
				case *v1.Pod:
					return !assignedPod(t) && responsibleForPod(t, args.SchedulerName)
				case cache.DeletedFinalStateUnknown:
					if pod, ok := t.Obj.(*v1.Pod); ok {
						return !assignedPod(pod) && responsibleForPod(pod, args.SchedulerName)
					}
					runtime.HandleError(fmt.Errorf("unable to convert object %T to *v1.Pod in %T", obj, c))
					return false
				default:
					runtime.HandleError(fmt.Errorf("unable to handle object in %T: %T", c, obj))
					return false
				}
			},
			Handler: cache.ResourceEventHandlerFuncs{
				AddFunc:    c.addPodToSchedulingQueue,
				UpdateFunc: c.updatePodInSchedulingQueue,
				DeleteFunc: c.deletePodFromSchedulingQueue,
			},
		},
	)
	// ScheduledPodLister is something we provide to plug-in functions that
	// they may need to call.
	c.scheduledPodLister = assignedPodLister{args.PodInformer.Lister()}

	args.NodeInformer.Informer().AddEventHandler(
		cache.ResourceEventHandlerFuncs{
			AddFunc:    c.addNodeToCache,
			UpdateFunc: c.updateNodeInCache,
			DeleteFunc: c.deleteNodeFromCache,
		},
	)

	// On add and delete of PVs, it will affect equivalence cache items
	// related to persistent volume
	args.PvInformer.Informer().AddEventHandler(
		cache.ResourceEventHandlerFuncs{
			// MaxPDVolumeCountPredicate: since it relies on the counts of PV.
			AddFunc:    c.onPvAdd,
			UpdateFunc: c.onPvUpdate,
			DeleteFunc: c.onPvDelete,
		},
	)

	// This is for MaxPDVolumeCountPredicate: add/delete PVC will affect counts of PV when it is bound.
	args.PvcInformer.Informer().AddEventHandler(
		cache.ResourceEventHandlerFuncs{
			AddFunc:    c.onPvcAdd,
			UpdateFunc: c.onPvcUpdate,
			DeleteFunc: c.onPvcDelete,
		},
	)

	// This is for ServiceAffinity: affected by the selector of the service is updated.
	// Also, if new service is added, equivalence cache will also become invalid since
	// existing pods may be "captured" by this service and change this predicate result.
	args.ServiceInformer.Informer().AddEventHandler(
		cache.ResourceEventHandlerFuncs{
			AddFunc:    c.onServiceAdd,
			UpdateFunc: c.onServiceUpdate,
			DeleteFunc: c.onServiceDelete,
		},
	)

	// Existing equivalence cache should not be affected by add/delete RC/Deployment etc,
	// it only make sense when pod is scheduled or deleted

	if utilfeature.DefaultFeatureGate.Enabled(features.VolumeScheduling) {
		// Setup volume binder
		c.volumeBinder = volumebinder.NewVolumeBinder(args.Client, args.PvcInformer, args.PvInformer, args.StorageClassInformer, time.Duration(args.BindTimeoutSeconds)*time.Second)

		args.StorageClassInformer.Informer().AddEventHandler(
			cache.ResourceEventHandlerFuncs{
				AddFunc:    c.onStorageClassAdd,
				DeleteFunc: c.onStorageClassDelete,
			},
		)
	}

	// Setup cache comparer
	comparer := cachecomparer.New(
		args.NodeInformer.Lister(),
		args.PodInformer.Lister(),
		c.schedulerCache,
		c.podQueue,
	)

	ch := make(chan os.Signal, 1)
	signal.Notify(ch, compareSignal)

	go func() {
		for {
			select {
			case <-c.StopEverything:
				c.podQueue.Close()
				return
			case <-ch:
				comparer.Compare()
			}
		}
	}()

	return c
}

// skipPodUpdate checks whether the specified pod update should be ignored.
// This function will return true if
//   - The pod has already been assumed, AND
//   - The pod has only its ResourceVersion, Spec.NodeName and/or Annotations
//     updated.
func (c *configFactory) skipPodUpdate(pod *v1.Pod) bool {
	// Non-assumed pods should never be skipped.
	isAssumed, err := c.schedulerCache.IsAssumedPod(pod)
	if err != nil {
		runtime.HandleError(fmt.Errorf("failed to check whether pod %s/%s is assumed: %v", pod.Namespace, pod.Name, err))
		return false
	}
	if !isAssumed {
		return false
	}

	// Gets the assumed pod from the cache.
	assumedPod, err := c.schedulerCache.GetPod(pod)
	if err != nil {
		runtime.HandleError(fmt.Errorf("failed to get assumed pod %s/%s from cache: %v", pod.Namespace, pod.Name, err))
		return false
	}

	// Compares the assumed pod in the cache with the pod update. If they are
	// equal (with certain fields excluded), this pod update will be skipped.
	f := func(pod *v1.Pod) *v1.Pod {
		p := pod.DeepCopy()
		// ResourceVersion must be excluded because each object update will
		// have a new resource version.
		p.ResourceVersion = ""
		// Spec.NodeName must be excluded because the pod assumed in the cache
		// is expected to have a node assigned while the pod update may nor may
		// not have this field set.
		p.Spec.NodeName = ""
		// Annotations must be excluded for the reasons described in
		// https://github.com/kubernetes/kubernetes/issues/52914.
		p.Annotations = nil
		return p
	}
	assumedPodCopy, podCopy := f(assumedPod), f(pod)
	if !reflect.DeepEqual(assumedPodCopy, podCopy) {
		return false
	}
	glog.V(3).Infof("Skipping pod %s/%s update", pod.Namespace, pod.Name)
	return true
}

func (c *configFactory) onPvAdd(obj interface{}) {
	if c.enableEquivalenceClassCache {
		pv, ok := obj.(*v1.PersistentVolume)
		if !ok {
			glog.Errorf("cannot convert to *v1.PersistentVolume: %v", obj)
			return
		}
		c.invalidatePredicatesForPv(pv)
	}
	// Pods created when there are no PVs available will be stuck in
	// unschedulable queue. But unbound PVs created for static provisioning and
	// delay binding storage class are skipped in PV controller dynamic
	// provisiong and binding process, will not trigger events to schedule pod
	// again. So we need to move pods to active queue on PV add for this
	// scenario.
	c.podQueue.MoveAllToActiveQueue()
}

func (c *configFactory) onPvUpdate(old, new interface{}) {
	if c.enableEquivalenceClassCache {
		newPV, ok := new.(*v1.PersistentVolume)
		if !ok {
			glog.Errorf("cannot convert to *v1.PersistentVolume: %v", new)
			return
		}
		oldPV, ok := old.(*v1.PersistentVolume)
		if !ok {
			glog.Errorf("cannot convert to *v1.PersistentVolume: %v", old)
			return
		}
		c.invalidatePredicatesForPvUpdate(oldPV, newPV)
	}
	// Scheduler.bindVolumesWorker may fail to update assumed pod volume
	// bindings due to conflicts if PVs are updated by PV controller or other
	// parties, then scheduler will add pod back to unschedulable queue. We
	// need to move pods to active queue on PV update for this scenario.
	c.podQueue.MoveAllToActiveQueue()
}

func (c *configFactory) invalidatePredicatesForPvUpdate(oldPV, newPV *v1.PersistentVolume) {
	invalidPredicates := sets.NewString()
	// CheckVolumeBinding predicate calls SchedulerVolumeBinder.FindPodVolumes
	// which will cache PVs in PodBindingCache. When PV got updated, we should
	// invalidate cache, otherwise PVAssumeCache.Assume will fail with out of sync
	// error.
	if utilfeature.DefaultFeatureGate.Enabled(features.VolumeScheduling) {
		invalidPredicates.Insert(predicates.CheckVolumeBindingPred)
	}
	for k, v := range newPV.Labels {
		// If PV update modifies the zone/region labels.
		if isZoneRegionLabel(k) && !reflect.DeepEqual(v, oldPV.Labels[k]) {
			invalidPredicates.Insert(predicates.NoVolumeZoneConflictPred)
			break
		}
	}
	c.equivalencePodCache.InvalidatePredicates(invalidPredicates)
}

// isZoneRegionLabel check if given key of label is zone or region label.
func isZoneRegionLabel(k string) bool {
	return k == kubeletapis.LabelZoneFailureDomain || k == kubeletapis.LabelZoneRegion
}

func (c *configFactory) onPvDelete(obj interface{}) {
	if c.enableEquivalenceClassCache {
		var pv *v1.PersistentVolume
		switch t := obj.(type) {
		case *v1.PersistentVolume:
			pv = t
		case cache.DeletedFinalStateUnknown:
			var ok bool
			pv, ok = t.Obj.(*v1.PersistentVolume)
			if !ok {
				glog.Errorf("cannot convert to *v1.PersistentVolume: %v", t.Obj)
				return
			}
		default:
			glog.Errorf("cannot convert to *v1.PersistentVolume: %v", t)
			return
		}
		c.invalidatePredicatesForPv(pv)
	}
}

func (c *configFactory) invalidatePredicatesForPv(pv *v1.PersistentVolume) {
	// You could have a PVC that points to a PV, but the PV object doesn't exist.
	// So when the PV object gets added, we can recount.
	invalidPredicates := sets.NewString()

	// PV types which impact MaxPDVolumeCountPredicate
	if pv.Spec.AWSElasticBlockStore != nil {
		invalidPredicates.Insert(predicates.MaxEBSVolumeCountPred)
	}
	if pv.Spec.GCEPersistentDisk != nil {
		invalidPredicates.Insert(predicates.MaxGCEPDVolumeCountPred)
	}
	if pv.Spec.AzureDisk != nil {
		invalidPredicates.Insert(predicates.MaxAzureDiskVolumeCountPred)
	}

	if pv.Spec.CSI != nil && utilfeature.DefaultFeatureGate.Enabled(features.AttachVolumeLimit) {
		invalidPredicates.Insert(predicates.MaxCSIVolumeCountPred)
	}

	// If PV contains zone related label, it may impact cached NoVolumeZoneConflict
	for k := range pv.Labels {
		if isZoneRegionLabel(k) {
			invalidPredicates.Insert(predicates.NoVolumeZoneConflictPred)
			break
		}
	}

	if utilfeature.DefaultFeatureGate.Enabled(features.VolumeScheduling) {
		// Add/delete impacts the available PVs to choose from
		invalidPredicates.Insert(predicates.CheckVolumeBindingPred)
	}

	c.equivalencePodCache.InvalidatePredicates(invalidPredicates)
}

func (c *configFactory) onPvcAdd(obj interface{}) {
	if c.enableEquivalenceClassCache {
		pvc, ok := obj.(*v1.PersistentVolumeClaim)
		if !ok {
			glog.Errorf("cannot convert to *v1.PersistentVolumeClaim: %v", obj)
			return
		}
		c.invalidatePredicatesForPvc(pvc)
	}
	c.podQueue.MoveAllToActiveQueue()
}

func (c *configFactory) onPvcUpdate(old, new interface{}) {
	if !utilfeature.DefaultFeatureGate.Enabled(features.VolumeScheduling) {
		return
	}

	if c.enableEquivalenceClassCache {
		newPVC, ok := new.(*v1.PersistentVolumeClaim)
		if !ok {
			glog.Errorf("cannot convert to *v1.PersistentVolumeClaim: %v", new)
			return
		}
		oldPVC, ok := old.(*v1.PersistentVolumeClaim)
		if !ok {
			glog.Errorf("cannot convert to *v1.PersistentVolumeClaim: %v", old)
			return
		}
		c.invalidatePredicatesForPvcUpdate(oldPVC, newPVC)
	}
	c.podQueue.MoveAllToActiveQueue()
}

func (c *configFactory) onPvcDelete(obj interface{}) {
	if c.enableEquivalenceClassCache {
		var pvc *v1.PersistentVolumeClaim
		switch t := obj.(type) {
		case *v1.PersistentVolumeClaim:
			pvc = t
		case cache.DeletedFinalStateUnknown:
			var ok bool
			pvc, ok = t.Obj.(*v1.PersistentVolumeClaim)
			if !ok {
				glog.Errorf("cannot convert to *v1.PersistentVolumeClaim: %v", t.Obj)
				return
			}
		default:
			glog.Errorf("cannot convert to *v1.PersistentVolumeClaim: %v", t)
			return
		}
		c.invalidatePredicatesForPvc(pvc)
	}
}

func (c *configFactory) invalidatePredicatesForPvc(pvc *v1.PersistentVolumeClaim) {
	// We need to do this here because the ecache uses PVC uid as part of equivalence hash of pod

	// The bound volume type may change
	invalidPredicates := sets.NewString(maxPDVolumeCountPredicateKeys...)

	if utilfeature.DefaultFeatureGate.Enabled(features.AttachVolumeLimit) {
		invalidPredicates.Insert(predicates.MaxCSIVolumeCountPred)
	}

	// The bound volume's label may change
	invalidPredicates.Insert(predicates.NoVolumeZoneConflictPred)

	if utilfeature.DefaultFeatureGate.Enabled(features.VolumeScheduling) {
		// Add/delete impacts the available PVs to choose from
		invalidPredicates.Insert(predicates.CheckVolumeBindingPred)
	}
	c.equivalencePodCache.InvalidatePredicates(invalidPredicates)
}

func (c *configFactory) invalidatePredicatesForPvcUpdate(old, new *v1.PersistentVolumeClaim) {
	invalidPredicates := sets.NewString()

	if old.Spec.VolumeName != new.Spec.VolumeName {
		if utilfeature.DefaultFeatureGate.Enabled(features.VolumeScheduling) {
			// PVC volume binding has changed
			invalidPredicates.Insert(predicates.CheckVolumeBindingPred)
		}
		// The bound volume type may change
		invalidPredicates.Insert(maxPDVolumeCountPredicateKeys...)

		if utilfeature.DefaultFeatureGate.Enabled(features.AttachVolumeLimit) {
			invalidPredicates.Insert(predicates.MaxCSIVolumeCountPred)
		}
	}

	c.equivalencePodCache.InvalidatePredicates(invalidPredicates)
}

func (c *configFactory) onStorageClassAdd(obj interface{}) {
	sc, ok := obj.(*storagev1.StorageClass)
	if !ok {
		glog.Errorf("cannot convert to *storagev1.StorageClass: %v", obj)
		return
	}

	// CheckVolumeBindingPred fails if pod has unbound immediate PVCs. If these
	// PVCs have specified StorageClass name, creating StorageClass objects
	// with late binding will cause predicates to pass, so we need to move pods
	// to active queue.
	// We don't need to invalidate cached results because results will not be
	// cached for pod that has unbound immediate PVCs.
	if sc.VolumeBindingMode != nil && *sc.VolumeBindingMode == storagev1.VolumeBindingWaitForFirstConsumer {
		c.podQueue.MoveAllToActiveQueue()
	}
}

func (c *configFactory) onStorageClassDelete(obj interface{}) {
	if c.enableEquivalenceClassCache {
		var sc *storagev1.StorageClass
		switch t := obj.(type) {
		case *storagev1.StorageClass:
			sc = t
		case cache.DeletedFinalStateUnknown:
			var ok bool
			sc, ok = t.Obj.(*storagev1.StorageClass)
			if !ok {
				glog.Errorf("cannot convert to *storagev1.StorageClass: %v", t.Obj)
				return
			}
		default:
			glog.Errorf("cannot convert to *storagev1.StorageClass: %v", t)
			return
		}
		c.invalidatePredicatesForStorageClass(sc)
	}
}

func (c *configFactory) invalidatePredicatesForStorageClass(sc *storagev1.StorageClass) {
	invalidPredicates := sets.NewString()

	if utilfeature.DefaultFeatureGate.Enabled(features.VolumeScheduling) {
		if sc.VolumeBindingMode != nil && *sc.VolumeBindingMode == storagev1.VolumeBindingWaitForFirstConsumer {
			// Delete can cause predicates to fail
			invalidPredicates.Insert(predicates.CheckVolumeBindingPred)
			invalidPredicates.Insert(predicates.NoVolumeZoneConflictPred)
		}
	}

	c.equivalencePodCache.InvalidatePredicates(invalidPredicates)
}

func (c *configFactory) onServiceAdd(obj interface{}) {
	if c.enableEquivalenceClassCache {
		c.equivalencePodCache.InvalidatePredicates(serviceAffinitySet)
	}
	c.podQueue.MoveAllToActiveQueue()
}

func (c *configFactory) onServiceUpdate(oldObj interface{}, newObj interface{}) {
	if c.enableEquivalenceClassCache {
		// TODO(resouer) We may need to invalidate this for specified group of pods only
		oldService := oldObj.(*v1.Service)
		newService := newObj.(*v1.Service)
		if !reflect.DeepEqual(oldService.Spec.Selector, newService.Spec.Selector) {
			c.equivalencePodCache.InvalidatePredicates(serviceAffinitySet)
		}
	}
	c.podQueue.MoveAllToActiveQueue()
}

func (c *configFactory) onServiceDelete(obj interface{}) {
	if c.enableEquivalenceClassCache {
		c.equivalencePodCache.InvalidatePredicates(serviceAffinitySet)
	}
	c.podQueue.MoveAllToActiveQueue()
}

// GetNodeStore provides the cache to the nodes, mostly internal use, but may also be called by mock-tests.
func (c *configFactory) GetNodeLister() corelisters.NodeLister {
	return c.nodeLister
}

func (c *configFactory) GetHardPodAffinitySymmetricWeight() int32 {
	return c.hardPodAffinitySymmetricWeight
}

func (c *configFactory) GetSchedulerName() string {
	return c.schedulerName
}

// GetClient provides a kubernetes Client, mostly internal use, but may also be called by mock-tests.
func (c *configFactory) GetClient() clientset.Interface {
	return c.client
}

// GetScheduledPodListerIndexer provides a pod lister, mostly internal use, but may also be called by mock-tests.
func (c *configFactory) GetScheduledPodLister() corelisters.PodLister {
	return c.scheduledPodLister
}

func (c *configFactory) addPodToCache(obj interface{}) {
	pod, ok := obj.(*v1.Pod)
	if !ok {
		glog.Errorf("cannot convert to *v1.Pod: %v", obj)
		return
	}

	if err := c.schedulerCache.AddPod(pod); err != nil {
		glog.Errorf("scheduler cache AddPod failed: %v", err)
	}

	c.podQueue.AssignedPodAdded(pod)

	// NOTE: Updating equivalence cache of addPodToCache has been
	// handled optimistically in: pkg/scheduler/scheduler.go#assume()
}

func (c *configFactory) updatePodInCache(oldObj, newObj interface{}) {
	oldPod, ok := oldObj.(*v1.Pod)
	if !ok {
		glog.Errorf("cannot convert oldObj to *v1.Pod: %v", oldObj)
		return
	}
	newPod, ok := newObj.(*v1.Pod)
	if !ok {
		glog.Errorf("cannot convert newObj to *v1.Pod: %v", newObj)
		return
	}

	// NOTE: Updates must be written to scheduler cache before invalidating
	// equivalence cache, because we could snapshot equivalence cache after the
	// invalidation and then snapshot the cache itself. If the cache is
	// snapshotted before updates are written, we would update equivalence
	// cache with stale information which is based on snapshot of old cache.
	if err := c.schedulerCache.UpdatePod(oldPod, newPod); err != nil {
		glog.Errorf("scheduler cache UpdatePod failed: %v", err)
	}

	c.invalidateCachedPredicatesOnUpdatePod(newPod, oldPod)
	c.podQueue.AssignedPodUpdated(newPod)
}

func (c *configFactory) addPodToSchedulingQueue(obj interface{}) {
	if err := c.podQueue.Add(obj.(*v1.Pod)); err != nil {
		runtime.HandleError(fmt.Errorf("unable to queue %T: %v", obj, err))
	}
}

func (c *configFactory) updatePodInSchedulingQueue(oldObj, newObj interface{}) {
	pod := newObj.(*v1.Pod)
	if c.skipPodUpdate(pod) {
		return
	}
	if err := c.podQueue.Update(oldObj.(*v1.Pod), pod); err != nil {
		runtime.HandleError(fmt.Errorf("unable to update %T: %v", newObj, err))
	}
}

func (c *configFactory) deletePodFromSchedulingQueue(obj interface{}) {
	var pod *v1.Pod
	switch t := obj.(type) {
	case *v1.Pod:
		pod = obj.(*v1.Pod)
	case cache.DeletedFinalStateUnknown:
		var ok bool
		pod, ok = t.Obj.(*v1.Pod)
		if !ok {
			runtime.HandleError(fmt.Errorf("unable to convert object %T to *v1.Pod in %T", obj, c))
			return
		}
	default:
		runtime.HandleError(fmt.Errorf("unable to handle object in %T: %T", c, obj))
		return
	}
	if err := c.podQueue.Delete(pod); err != nil {
		runtime.HandleError(fmt.Errorf("unable to dequeue %T: %v", obj, err))
	}
	if c.volumeBinder != nil {
		// Volume binder only wants to keep unassigned pods
		c.volumeBinder.DeletePodBindings(pod)
	}
}

func (c *configFactory) invalidateCachedPredicatesOnUpdatePod(newPod *v1.Pod, oldPod *v1.Pod) {
	if c.enableEquivalenceClassCache {
		// if the pod does not have bound node, updating equivalence cache is meaningless;
		// if pod's bound node has been changed, that case should be handled by pod add & delete.
		if len(newPod.Spec.NodeName) != 0 && newPod.Spec.NodeName == oldPod.Spec.NodeName {
			if !reflect.DeepEqual(oldPod.GetLabels(), newPod.GetLabels()) {
				// MatchInterPodAffinity need to be reconsidered for this node,
				// as well as all nodes in its same failure domain.
				c.equivalencePodCache.InvalidatePredicates(
					matchInterPodAffinitySet)
			}
			// if requested container resource changed, invalidate GeneralPredicates of this node
			if !reflect.DeepEqual(predicates.GetResourceRequest(newPod),
				predicates.GetResourceRequest(oldPod)) {
				c.equivalencePodCache.InvalidatePredicatesOnNode(
					newPod.Spec.NodeName, generalPredicatesSets)
			}
		}
	}
}

func (c *configFactory) deletePodFromCache(obj interface{}) {
	var pod *v1.Pod
	switch t := obj.(type) {
	case *v1.Pod:
		pod = t
	case cache.DeletedFinalStateUnknown:
		var ok bool
		pod, ok = t.Obj.(*v1.Pod)
		if !ok {
			glog.Errorf("cannot convert to *v1.Pod: %v", t.Obj)
			return
		}
	default:
		glog.Errorf("cannot convert to *v1.Pod: %v", t)
		return
	}
	// NOTE: Updates must be written to scheduler cache before invalidating
	// equivalence cache, because we could snapshot equivalence cache after the
	// invalidation and then snapshot the cache itself. If the cache is
	// snapshotted before updates are written, we would update equivalence
	// cache with stale information which is based on snapshot of old cache.
	if err := c.schedulerCache.RemovePod(pod); err != nil {
		glog.Errorf("scheduler cache RemovePod failed: %v", err)
	}

	c.invalidateCachedPredicatesOnDeletePod(pod)
	c.podQueue.MoveAllToActiveQueue()
}

func (c *configFactory) invalidateCachedPredicatesOnDeletePod(pod *v1.Pod) {
	if c.enableEquivalenceClassCache {
		// part of this case is the same as pod add.
		c.equivalencePodCache.InvalidateCachedPredicateItemForPodAdd(pod, pod.Spec.NodeName)
		// MatchInterPodAffinity need to be reconsidered for this node,
		// as well as all nodes in its same failure domain.
		// TODO(resouer) can we just do this for nodes in the same failure domain
		c.equivalencePodCache.InvalidatePredicates(
			matchInterPodAffinitySet)

		// if this pod have these PV, cached result of disk conflict will become invalid.
		for _, volume := range pod.Spec.Volumes {
			if volume.GCEPersistentDisk != nil || volume.AWSElasticBlockStore != nil ||
				volume.RBD != nil || volume.ISCSI != nil {
				c.equivalencePodCache.InvalidatePredicatesOnNode(
					pod.Spec.NodeName, noDiskConflictSet)
			}
		}
	}
}

func (c *configFactory) addNodeToCache(obj interface{}) {
	node, ok := obj.(*v1.Node)
	if !ok {
		glog.Errorf("cannot convert to *v1.Node: %v", obj)
		return
	}

	// NOTE: Because the scheduler uses equivalence cache for nodes, we need
	// to create it before adding node into scheduler cache.
	if c.enableEquivalenceClassCache {
		// GetNodeCache() will lazily create NodeCache for given node if it does not exist.
		c.equivalencePodCache.GetNodeCache(node.GetName())
	}

	if err := c.schedulerCache.AddNode(node); err != nil {
		glog.Errorf("scheduler cache AddNode failed: %v", err)
	}

	c.podQueue.MoveAllToActiveQueue()
	// NOTE: add a new node does not affect existing predicates in equivalence cache
}

func (c *configFactory) updateNodeInCache(oldObj, newObj interface{}) {
	oldNode, ok := oldObj.(*v1.Node)
	if !ok {
		glog.Errorf("cannot convert oldObj to *v1.Node: %v", oldObj)
		return
	}
	newNode, ok := newObj.(*v1.Node)
	if !ok {
		glog.Errorf("cannot convert newObj to *v1.Node: %v", newObj)
		return
	}

	// NOTE: Updates must be written to scheduler cache before invalidating
	// equivalence cache, because we could snapshot equivalence cache after the
	// invalidation and then snapshot the cache itself. If the cache is
	// snapshotted before updates are written, we would update equivalence
	// cache with stale information which is based on snapshot of old cache.
	if err := c.schedulerCache.UpdateNode(oldNode, newNode); err != nil {
		glog.Errorf("scheduler cache UpdateNode failed: %v", err)
	}

	c.invalidateCachedPredicatesOnNodeUpdate(newNode, oldNode)
	// Only activate unschedulable pods if the node became more schedulable.
	if nodeSchedulingPropertiesChanged(newNode, oldNode) {
		c.podQueue.MoveAllToActiveQueue()
	}
}

func (c *configFactory) invalidateCachedPredicatesOnNodeUpdate(newNode *v1.Node, oldNode *v1.Node) {
	if c.enableEquivalenceClassCache {
		// Begin to update equivalence cache based on node update
		// TODO(resouer): think about lazily initialize this set
		invalidPredicates := sets.NewString()

		if !reflect.DeepEqual(oldNode.Status.Allocatable, newNode.Status.Allocatable) {
			invalidPredicates.Insert(predicates.GeneralPred) // "PodFitsResources"
		}
		if !reflect.DeepEqual(oldNode.GetLabels(), newNode.GetLabels()) {
			invalidPredicates.Insert(predicates.GeneralPred, predicates.CheckServiceAffinityPred) // "PodSelectorMatches"
			for k, v := range oldNode.GetLabels() {
				// any label can be topology key of pod, we have to invalidate in all cases
				if v != newNode.GetLabels()[k] {
					invalidPredicates.Insert(predicates.MatchInterPodAffinityPred)
				}
				// NoVolumeZoneConflict will only be affected by zone related label change
				if isZoneRegionLabel(k) {
					if v != newNode.GetLabels()[k] {
						invalidPredicates.Insert(predicates.NoVolumeZoneConflictPred)
					}
				}
			}
		}

		oldTaints, oldErr := helper.GetTaintsFromNodeAnnotations(oldNode.GetAnnotations())
		if oldErr != nil {
			glog.Errorf("Failed to get taints from old node annotation for equivalence cache")
		}
		newTaints, newErr := helper.GetTaintsFromNodeAnnotations(newNode.GetAnnotations())
		if newErr != nil {
			glog.Errorf("Failed to get taints from new node annotation for equivalence cache")
		}
		if !reflect.DeepEqual(oldTaints, newTaints) ||
			!reflect.DeepEqual(oldNode.Spec.Taints, newNode.Spec.Taints) {
			invalidPredicates.Insert(predicates.PodToleratesNodeTaintsPred)
		}

		if !reflect.DeepEqual(oldNode.Status.Conditions, newNode.Status.Conditions) {
			oldConditions := make(map[v1.NodeConditionType]v1.ConditionStatus)
			newConditions := make(map[v1.NodeConditionType]v1.ConditionStatus)
			for _, cond := range oldNode.Status.Conditions {
				oldConditions[cond.Type] = cond.Status
			}
			for _, cond := range newNode.Status.Conditions {
				newConditions[cond.Type] = cond.Status
			}
			if oldConditions[v1.NodeMemoryPressure] != newConditions[v1.NodeMemoryPressure] {
				invalidPredicates.Insert(predicates.CheckNodeMemoryPressurePred)
			}
			if oldConditions[v1.NodeDiskPressure] != newConditions[v1.NodeDiskPressure] {
				invalidPredicates.Insert(predicates.CheckNodeDiskPressurePred)
			}
			if oldConditions[v1.NodePIDPressure] != newConditions[v1.NodePIDPressure] {
				invalidPredicates.Insert(predicates.CheckNodePIDPressurePred)
			}
			if oldConditions[v1.NodeReady] != newConditions[v1.NodeReady] ||
				oldConditions[v1.NodeOutOfDisk] != newConditions[v1.NodeOutOfDisk] ||
				oldConditions[v1.NodeNetworkUnavailable] != newConditions[v1.NodeNetworkUnavailable] {
				invalidPredicates.Insert(predicates.CheckNodeConditionPred)
			}
		}
		if newNode.Spec.Unschedulable != oldNode.Spec.Unschedulable {
			invalidPredicates.Insert(predicates.CheckNodeConditionPred)
		}
		c.equivalencePodCache.InvalidatePredicatesOnNode(newNode.GetName(), invalidPredicates)
	}
}

func nodeSchedulingPropertiesChanged(newNode *v1.Node, oldNode *v1.Node) bool {
	if nodeAllocatableChanged(newNode, oldNode) {
		glog.V(4).Infof("Allocatable resource of node %s changed", newNode.Name)
		return true
	}
	if nodeLabelsChanged(newNode, oldNode) {
		glog.V(4).Infof("Labels of node %s changed", newNode.Name)
		return true
	}
	if nodeTaintsChanged(newNode, oldNode) {
		glog.V(4).Infof("Taints of node %s changed", newNode.Name)
		return true
	}
	if nodeConditionsChanged(newNode, oldNode) {
		glog.V(4).Infof("Conditions of node %s changed", newNode.Name)
		return true
	}
	if newNode.Spec.Unschedulable != oldNode.Spec.Unschedulable && newNode.Spec.Unschedulable == false {
		glog.V(4).Infof("Node %s changed to schedulable", newNode.Name)
		return true
	}
	return false
}

func nodeAllocatableChanged(newNode *v1.Node, oldNode *v1.Node) bool {
	return !reflect.DeepEqual(oldNode.Status.Allocatable, newNode.Status.Allocatable)
}

func nodeLabelsChanged(newNode *v1.Node, oldNode *v1.Node) bool {
	return !reflect.DeepEqual(oldNode.GetLabels(), newNode.GetLabels())
}

func nodeTaintsChanged(newNode *v1.Node, oldNode *v1.Node) bool {
	if !reflect.DeepEqual(newNode.Spec.Taints, oldNode.Spec.Taints) {
		return true
	}
	oldTaints, oldErr := helper.GetTaintsFromNodeAnnotations(oldNode.GetAnnotations())
	if oldErr != nil {
		// If parse old node's taint annotation failed, we assume node's taint changed.
		glog.Errorf("Failed to get taints from annotation of old node %s: %v", oldNode.Name, oldErr)
		return true
	}
	newTaints, newErr := helper.GetTaintsFromNodeAnnotations(newNode.GetAnnotations())
	if newErr != nil {
		// If parse new node's taint annotation failed, we assume node's taint changed.
		glog.Errorf("Failed to get taints from annotation of new node %s: %v", newNode.Name, newErr)
		return true
	}
	if !reflect.DeepEqual(oldTaints, newTaints) {
		return true
	}
	return false
}

func nodeConditionsChanged(newNode *v1.Node, oldNode *v1.Node) bool {
	return !reflect.DeepEqual(oldNode.Status.Conditions, newNode.Status.Conditions)
}

func (c *configFactory) deleteNodeFromCache(obj interface{}) {
	var node *v1.Node
	switch t := obj.(type) {
	case *v1.Node:
		node = t
	case cache.DeletedFinalStateUnknown:
		var ok bool
		node, ok = t.Obj.(*v1.Node)
		if !ok {
			glog.Errorf("cannot convert to *v1.Node: %v", t.Obj)
			return
		}
	default:
		glog.Errorf("cannot convert to *v1.Node: %v", t)
		return
	}
	// NOTE: Updates must be written to scheduler cache before invalidating
	// equivalence cache, because we could snapshot equivalence cache after the
	// invalidation and then snapshot the cache itself. If the cache is
	// snapshotted before updates are written, we would update equivalence
	// cache with stale information which is based on snapshot of old cache.
	if err := c.schedulerCache.RemoveNode(node); err != nil {
		glog.Errorf("scheduler cache RemoveNode failed: %v", err)
	}
	if c.enableEquivalenceClassCache {
		c.equivalencePodCache.InvalidateAllPredicatesOnNode(node.GetName())
	}
}

// Create creates a scheduler with the default algorithm provider.
func (c *configFactory) Create() (*Config, error) {
	return c.CreateFromProvider(DefaultProvider)
}

// Creates a scheduler from the name of a registered algorithm provider.
func (c *configFactory) CreateFromProvider(providerName string) (*Config, error) {
	glog.V(2).Infof("Creating scheduler from algorithm provider '%v'", providerName)
	provider, err := GetAlgorithmProvider(providerName)
	if err != nil {
		return nil, err
	}
	return c.CreateFromKeys(provider.FitPredicateKeys, provider.PriorityFunctionKeys, []algorithm.SchedulerExtender{})
}

// Creates a scheduler from the configuration file
func (c *configFactory) CreateFromConfig(policy schedulerapi.Policy) (*Config, error) {
	glog.V(2).Infof("Creating scheduler from configuration: %v", policy)

	// validate the policy configuration
	if err := validation.ValidatePolicy(policy); err != nil {
		return nil, err
	}

	predicateKeys := sets.NewString()
	if policy.Predicates == nil {
		glog.V(2).Infof("Using predicates from algorithm provider '%v'", DefaultProvider)
		provider, err := GetAlgorithmProvider(DefaultProvider)
		if err != nil {
			return nil, err
		}
		predicateKeys = provider.FitPredicateKeys
	} else {
		for _, predicate := range policy.Predicates {
			glog.V(2).Infof("Registering predicate: %s", predicate.Name)
			predicateKeys.Insert(RegisterCustomFitPredicate(predicate))
		}
	}

	priorityKeys := sets.NewString()
	if policy.Priorities == nil {
		glog.V(2).Infof("Using priorities from algorithm provider '%v'", DefaultProvider)
		provider, err := GetAlgorithmProvider(DefaultProvider)
		if err != nil {
			return nil, err
		}
		priorityKeys = provider.PriorityFunctionKeys
	} else {
		for _, priority := range policy.Priorities {
			glog.V(2).Infof("Registering priority: %s", priority.Name)
			priorityKeys.Insert(RegisterCustomPriorityFunction(priority))
		}
	}

	var extenders []algorithm.SchedulerExtender
	if len(policy.ExtenderConfigs) != 0 {
		ignoredExtendedResources := sets.NewString()
		for ii := range policy.ExtenderConfigs {
			glog.V(2).Infof("Creating extender with config %+v", policy.ExtenderConfigs[ii])
			extender, err := core.NewHTTPExtender(&policy.ExtenderConfigs[ii])
			if err != nil {
				return nil, err
			}
			extenders = append(extenders, extender)
			for _, r := range policy.ExtenderConfigs[ii].ManagedResources {
				if r.IgnoredByScheduler {
					ignoredExtendedResources.Insert(string(r.Name))
				}
			}
		}
		predicates.RegisterPredicateMetadataProducerWithExtendedResourceOptions(ignoredExtendedResources)
	}
	// Providing HardPodAffinitySymmetricWeight in the policy config is the new and preferred way of providing the value.
	// Give it higher precedence than scheduler CLI configuration when it is provided.
	if policy.HardPodAffinitySymmetricWeight != 0 {
		c.hardPodAffinitySymmetricWeight = policy.HardPodAffinitySymmetricWeight
	}
	// When AlwaysCheckAllPredicates is set to true, scheduler checks all the configured
	// predicates even after one or more of them fails.
	if policy.AlwaysCheckAllPredicates {
		c.alwaysCheckAllPredicates = policy.AlwaysCheckAllPredicates
	}

	return c.CreateFromKeys(predicateKeys, priorityKeys, extenders)
}

// getBinderFunc returns an func which returns an extender that supports bind or a default binder based on the given pod.
func (c *configFactory) getBinderFunc(extenders []algorithm.SchedulerExtender) func(pod *v1.Pod) Binder {
	var extenderBinder algorithm.SchedulerExtender
	for i := range extenders {
		if extenders[i].IsBinder() {
			extenderBinder = extenders[i]
			break
		}
	}
	defaultBinder := &binder{c.client}
	return func(pod *v1.Pod) Binder {
		if extenderBinder != nil && extenderBinder.IsInterested(pod) {
			return extenderBinder
		}
		return defaultBinder
	}
}

// Creates a scheduler from a set of registered fit predicate keys and priority keys.
func (c *configFactory) CreateFromKeys(predicateKeys, priorityKeys sets.String, extenders []algorithm.SchedulerExtender) (*Config, error) {
	glog.V(2).Infof("Creating scheduler with fit predicates '%v' and priority functions '%v'", predicateKeys, priorityKeys)

	if c.GetHardPodAffinitySymmetricWeight() < 1 || c.GetHardPodAffinitySymmetricWeight() > 100 {
		return nil, fmt.Errorf("invalid hardPodAffinitySymmetricWeight: %d, must be in the range 1-100", c.GetHardPodAffinitySymmetricWeight())
	}

	predicateFuncs, err := c.GetPredicates(predicateKeys)
	if err != nil {
		return nil, err
	}

	priorityConfigs, err := c.GetPriorityFunctionConfigs(priorityKeys)
	if err != nil {
		return nil, err
	}

	priorityMetaProducer, err := c.GetPriorityMetadataProducer()
	if err != nil {
		return nil, err
	}

	predicateMetaProducer, err := c.GetPredicateMetadataProducer()
	if err != nil {
		return nil, err
	}

	// Init equivalence class cache
	if c.enableEquivalenceClassCache {
		c.equivalencePodCache = equivalence.NewCache(predicates.Ordering())
		glog.Info("Created equivalence class cache")
	}

	algo := core.NewGenericScheduler(
		c.schedulerCache,
		c.equivalencePodCache,
		c.podQueue,
		predicateFuncs,
		predicateMetaProducer,
		priorityConfigs,
		priorityMetaProducer,
		extenders,
		c.volumeBinder,
		c.pVCLister,
		c.pdbLister,
		c.alwaysCheckAllPredicates,
		c.disablePreemption,
		c.percentageOfNodesToScore,
	)

	podBackoff := util.CreateDefaultPodBackoff()
	return &Config{
		SchedulerCache: c.schedulerCache,
		Ecache:         c.equivalencePodCache,
		// The scheduler only needs to consider schedulable nodes.
		NodeLister:          &nodeLister{c.nodeLister},
		Algorithm:           algo,
		GetBinder:           c.getBinderFunc(extenders),
		PodConditionUpdater: &podConditionUpdater{c.client},
		PodPreemptor:        &podPreemptor{c.client},
		WaitForCacheSync: func() bool {
			return cache.WaitForCacheSync(c.StopEverything, c.scheduledPodsHasSynced)
		},
		NextPod: func() *v1.Pod {
			return c.getNextPod()
		},
		Error:          c.MakeDefaultErrorFunc(podBackoff, c.podQueue),
		StopEverything: c.StopEverything,
		VolumeBinder:   c.volumeBinder,
	}, nil
}

type nodeLister struct {
	corelisters.NodeLister
}

func (n *nodeLister) List() ([]*v1.Node, error) {
	return n.NodeLister.List(labels.Everything())
}

func (c *configFactory) GetPriorityFunctionConfigs(priorityKeys sets.String) ([]algorithm.PriorityConfig, error) {
	pluginArgs, err := c.getPluginArgs()
	if err != nil {
		return nil, err
	}

	return getPriorityFunctionConfigs(priorityKeys, *pluginArgs)
}

func (c *configFactory) GetPriorityMetadataProducer() (algorithm.PriorityMetadataProducer, error) {
	pluginArgs, err := c.getPluginArgs()
	if err != nil {
		return nil, err
	}

	return getPriorityMetadataProducer(*pluginArgs)
}

func (c *configFactory) GetPredicateMetadataProducer() (algorithm.PredicateMetadataProducer, error) {
	pluginArgs, err := c.getPluginArgs()
	if err != nil {
		return nil, err
	}
	return getPredicateMetadataProducer(*pluginArgs)
}

func (c *configFactory) GetPredicates(predicateKeys sets.String) (map[string]algorithm.FitPredicate, error) {
	pluginArgs, err := c.getPluginArgs()
	if err != nil {
		return nil, err
	}

	return getFitPredicateFunctions(predicateKeys, *pluginArgs)
}

func (c *configFactory) getPluginArgs() (*PluginFactoryArgs, error) {
	return &PluginFactoryArgs{
		PodLister:                      c.podLister,
		ServiceLister:                  c.serviceLister,
		ControllerLister:               c.controllerLister,
		ReplicaSetLister:               c.replicaSetLister,
		StatefulSetLister:              c.statefulSetLister,
		NodeLister:                     &nodeLister{c.nodeLister},
		PDBLister:                      c.pdbLister,
		NodeInfo:                       &predicates.CachedNodeInfo{NodeLister: c.nodeLister},
		PVInfo:                         &predicates.CachedPersistentVolumeInfo{PersistentVolumeLister: c.pVLister},
		PVCInfo:                        &predicates.CachedPersistentVolumeClaimInfo{PersistentVolumeClaimLister: c.pVCLister},
		StorageClassInfo:               &predicates.CachedStorageClassInfo{StorageClassLister: c.storageClassLister},
		VolumeBinder:                   c.volumeBinder,
		HardPodAffinitySymmetricWeight: c.hardPodAffinitySymmetricWeight,
	}, nil
}

func (c *configFactory) getNextPod() *v1.Pod {
	pod, err := c.podQueue.Pop()
	if err == nil {
		glog.V(4).Infof("About to try and schedule pod %v/%v", pod.Namespace, pod.Name)
		return pod
	}
	glog.Errorf("Error while retrieving next pod from scheduling queue: %v", err)
	return nil
}

// assignedPod selects pods that are assigned (scheduled and running).
func assignedPod(pod *v1.Pod) bool {
	return len(pod.Spec.NodeName) != 0
}

// responsibleForPod returns true if the pod has asked to be scheduled by the given scheduler.
func responsibleForPod(pod *v1.Pod, schedulerName string) bool {
	return schedulerName == pod.Spec.SchedulerName
}

// assignedPodLister filters the pods returned from a PodLister to
// only include those that have a node name set.
type assignedPodLister struct {
	corelisters.PodLister
}

// List lists all Pods in the indexer for a given namespace.
func (l assignedPodLister) List(selector labels.Selector) ([]*v1.Pod, error) {
	list, err := l.PodLister.List(selector)
	if err != nil {
		return nil, err
	}
	filtered := make([]*v1.Pod, 0, len(list))
	for _, pod := range list {
		if len(pod.Spec.NodeName) > 0 {
			filtered = append(filtered, pod)
		}
	}
	return filtered, nil
}

// List lists all Pods in the indexer for a given namespace.
func (l assignedPodLister) Pods(namespace string) corelisters.PodNamespaceLister {
	return assignedPodNamespaceLister{l.PodLister.Pods(namespace)}
}

// assignedPodNamespaceLister filters the pods returned from a PodNamespaceLister to
// only include those that have a node name set.
type assignedPodNamespaceLister struct {
	corelisters.PodNamespaceLister
}

// List lists all Pods in the indexer for a given namespace.
func (l assignedPodNamespaceLister) List(selector labels.Selector) (ret []*v1.Pod, err error) {
	list, err := l.PodNamespaceLister.List(selector)
	if err != nil {
		return nil, err
	}
	filtered := make([]*v1.Pod, 0, len(list))
	for _, pod := range list {
		if len(pod.Spec.NodeName) > 0 {
			filtered = append(filtered, pod)
		}
	}
	return filtered, nil
}

// Get retrieves the Pod from the indexer for a given namespace and name.
func (l assignedPodNamespaceLister) Get(name string) (*v1.Pod, error) {
	pod, err := l.PodNamespaceLister.Get(name)
	if err != nil {
		return nil, err
	}
	if len(pod.Spec.NodeName) > 0 {
		return pod, nil
	}
	return nil, errors.NewNotFound(schema.GroupResource{Resource: string(v1.ResourcePods)}, name)
}

type podInformer struct {
	informer cache.SharedIndexInformer
}

func (i *podInformer) Informer() cache.SharedIndexInformer {
	return i.informer
}

func (i *podInformer) Lister() corelisters.PodLister {
	return corelisters.NewPodLister(i.informer.GetIndexer())
}

// NewPodInformer creates a shared index informer that returns only non-terminal pods.
func NewPodInformer(client clientset.Interface, resyncPeriod time.Duration) coreinformers.PodInformer {
	selector := fields.ParseSelectorOrDie(
		"status.phase!=" + string(v1.PodSucceeded) +
			",status.phase!=" + string(v1.PodFailed))
	lw := cache.NewListWatchFromClient(client.CoreV1().RESTClient(), string(v1.ResourcePods), metav1.NamespaceAll, selector)
	return &podInformer{
		informer: cache.NewSharedIndexInformer(lw, &v1.Pod{}, resyncPeriod, cache.Indexers{cache.NamespaceIndex: cache.MetaNamespaceIndexFunc}),
	}
}

func (c *configFactory) MakeDefaultErrorFunc(backoff *util.PodBackoff, podQueue internalqueue.SchedulingQueue) func(pod *v1.Pod, err error) {
	return func(pod *v1.Pod, err error) {
		if err == core.ErrNoNodesAvailable {
			glog.V(4).Infof("Unable to schedule %v/%v: no nodes are registered to the cluster; waiting", pod.Namespace, pod.Name)
		} else {
			if _, ok := err.(*core.FitError); ok {
				glog.V(4).Infof("Unable to schedule %v/%v: no fit: %v; waiting", pod.Namespace, pod.Name, err)
			} else if errors.IsNotFound(err) {
				if errStatus, ok := err.(errors.APIStatus); ok && errStatus.Status().Details.Kind == "node" {
					nodeName := errStatus.Status().Details.Name
					// when node is not found, We do not remove the node right away. Trying again to get
					// the node and if the node is still not found, then remove it from the scheduler cache.
					_, err := c.client.CoreV1().Nodes().Get(nodeName, metav1.GetOptions{})
					if err != nil && errors.IsNotFound(err) {
						node := v1.Node{ObjectMeta: metav1.ObjectMeta{Name: nodeName}}
						// NOTE: Updates must be written to scheduler cache before invalidating
						// equivalence cache, because we could snapshot equivalence cache after the
						// invalidation and then snapshot the cache itself. If the cache is
						// snapshotted before updates are written, we would update equivalence
						// cache with stale information which is based on snapshot of old cache.
						c.schedulerCache.RemoveNode(&node)
						// invalidate cached predicate for the node
						if c.enableEquivalenceClassCache {
							c.equivalencePodCache.InvalidateAllPredicatesOnNode(nodeName)
						}
					}
				}
			} else {
				glog.Errorf("Error scheduling %v/%v: %v; retrying", pod.Namespace, pod.Name, err)
			}
		}

		backoff.Gc()
		// Retry asynchronously.
		// Note that this is extremely rudimentary and we need a more real error handling path.
		go func() {
			defer runtime.HandleCrash()
			podID := types.NamespacedName{
				Namespace: pod.Namespace,
				Name:      pod.Name,
			}
			origPod := pod

			// When pod priority is enabled, we would like to place an unschedulable
			// pod in the unschedulable queue. This ensures that if the pod is nominated
			// to run on a node, scheduler takes the pod into account when running
			// predicates for the node.
			if !util.PodPriorityEnabled() {
				entry := backoff.GetEntry(podID)
				if !entry.TryWait(backoff.MaxDuration()) {
					glog.Warningf("Request for pod %v already in flight, abandoning", podID)
					return
				}
			}
			// Get the pod again; it may have changed/been scheduled already.
			getBackoff := initialGetBackoff
			for {
				pod, err := c.client.CoreV1().Pods(podID.Namespace).Get(podID.Name, metav1.GetOptions{})
				if err == nil {
					if len(pod.Spec.NodeName) == 0 {
						podQueue.AddUnschedulableIfNotPresent(pod)
					} else {
						if c.volumeBinder != nil {
							// Volume binder only wants to keep unassigned pods
							c.volumeBinder.DeletePodBindings(pod)
						}
					}
					break
				}
				if errors.IsNotFound(err) {
					glog.Warningf("A pod %v no longer exists", podID)

					if c.volumeBinder != nil {
						// Volume binder only wants to keep unassigned pods
						c.volumeBinder.DeletePodBindings(origPod)
					}
					return
				}
				glog.Errorf("Error getting pod %v for retry: %v; retrying...", podID, err)
				if getBackoff = getBackoff * 2; getBackoff > maximalGetBackoff {
					getBackoff = maximalGetBackoff
				}
				time.Sleep(getBackoff)
			}
		}()
	}
}

// nodeEnumerator allows a cache.Poller to enumerate items in an v1.NodeList
type nodeEnumerator struct {
	*v1.NodeList
}

// Len returns the number of items in the node list.
func (ne *nodeEnumerator) Len() int {
	if ne.NodeList == nil {
		return 0
	}
	return len(ne.Items)
}

// Get returns the item (and ID) with the particular index.
func (ne *nodeEnumerator) Get(index int) interface{} {
	return &ne.Items[index]
}

type binder struct {
	Client clientset.Interface
}

// Bind just does a POST binding RPC.
func (b *binder) Bind(binding *v1.Binding) error {
	glog.V(3).Infof("Attempting to bind %v to %v", binding.Name, binding.Target.Name)
	return b.Client.CoreV1().Pods(binding.Namespace).Bind(binding)
}

type podConditionUpdater struct {
	Client clientset.Interface
}

func (p *podConditionUpdater) Update(pod *v1.Pod, condition *v1.PodCondition) error {
	glog.V(3).Infof("Updating pod condition for %s/%s to (%s==%s)", pod.Namespace, pod.Name, condition.Type, condition.Status)
	if podutil.UpdatePodCondition(&pod.Status, condition) {
		_, err := p.Client.CoreV1().Pods(pod.Namespace).UpdateStatus(pod)
		return err
	}
	return nil
}

type podPreemptor struct {
	Client clientset.Interface
}

func (p *podPreemptor) GetUpdatedPod(pod *v1.Pod) (*v1.Pod, error) {
	return p.Client.CoreV1().Pods(pod.Namespace).Get(pod.Name, metav1.GetOptions{})
}

func (p *podPreemptor) DeletePod(pod *v1.Pod) error {
	return p.Client.CoreV1().Pods(pod.Namespace).Delete(pod.Name, &metav1.DeleteOptions{})
}

func (p *podPreemptor) SetNominatedNodeName(pod *v1.Pod, nominatedNodeName string) error {
	podCopy := pod.DeepCopy()
	podCopy.Status.NominatedNodeName = nominatedNodeName
	_, err := p.Client.CoreV1().Pods(pod.Namespace).UpdateStatus(podCopy)
	return err
}

func (p *podPreemptor) RemoveNominatedNodeName(pod *v1.Pod) error {
	if len(pod.Status.NominatedNodeName) == 0 {
		return nil
	}
	return p.SetNominatedNodeName(pod, "")
}