Add NEG Syncer, SyncerManager and interfaces

2017-10-03 13:55:26 -07:00 · 2017-10-03 13:55:26 -07:00 · b4cbc60fb7
commit b4cbc60fb7
parent 25bb9341e1
6 changed files with 1666 additions and 0 deletions
--- a/controllers/gce/networkendpointgroup/fakes.go
+++ b/controllers/gce/networkendpointgroup/fakes.go
@ -0,0 +1,194 @@
+/*
+Copyright 2017 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 networkendpointgroup
+
+import (
+	"fmt"
+	computealpha "google.golang.org/api/compute/v0.alpha"
+	"k8s.io/apimachinery/pkg/util/sets"
+	"reflect"
+	"sync"
+)
+
+const (
+	TestZone1     = "zone1"
+	TestZone2     = "zone2"
+	TestInstance1 = "instance1"
+	TestInstance2 = "instance2"
+	TestInstance3 = "instance3"
+	TestInstance4 = "instance4"
+)
+
+type fakeZoneGetter struct {
+	zoneInstanceMap map[string]sets.String
+}
+
+func NewFakeZoneGetter() *fakeZoneGetter {
+	return &fakeZoneGetter{
+		zoneInstanceMap: map[string]sets.String{
+			TestZone1: sets.NewString(TestInstance1, TestInstance2),
+			TestZone2: sets.NewString(TestInstance3, TestInstance4),
+		},
+	}
+}
+
+func (f *fakeZoneGetter) ListZones() ([]string, error) {
+	ret := []string{}
+	for key := range f.zoneInstanceMap {
+		ret = append(ret, key)
+	}
+	return ret, nil
+}
+func (f *fakeZoneGetter) GetZoneForNode(name string) (string, error) {
+	for zone, instances := range f.zoneInstanceMap {
+		if instances.Has(name) {
+			return zone, nil
+		}
+	}
+	return "", NotFoundError
+}
+
+type FakeNetworkEndpointGroupCloud struct {
+	NetworkEndpointGroups map[string][]*computealpha.NetworkEndpointGroup
+	NetworkEndpoints      map[string][]*computealpha.NetworkEndpoint
+	Subnetwork            string
+	Network               string
+	mu                    sync.Mutex
+}
+
+func NewFakeNetworkEndpointGroupCloud(subnetwork, network string) NetworkEndpointGroupCloud {
+	return &FakeNetworkEndpointGroupCloud{
+		Subnetwork:            subnetwork,
+		Network:               network,
+		NetworkEndpointGroups: map[string][]*computealpha.NetworkEndpointGroup{},
+		NetworkEndpoints:      map[string][]*computealpha.NetworkEndpoint{},
+	}
+}
+
+var NotFoundError = fmt.Errorf("Not Found")
+
+func (cloud *FakeNetworkEndpointGroupCloud) GetNetworkEndpointGroup(name string, zone string) (*computealpha.NetworkEndpointGroup, error) {
+	cloud.mu.Lock()
+	defer cloud.mu.Unlock()
+	negs, ok := cloud.NetworkEndpointGroups[zone]
+	if ok {
+		for _, neg := range negs {
+			if neg.Name == name {
+				return neg, nil
+			}
+		}
+	}
+	return nil, NotFoundError
+}
+
+func networkEndpointKey(name, zone string) string {
+	return fmt.Sprintf("%s-%s", zone, name)
+}
+
+func (cloud *FakeNetworkEndpointGroupCloud) ListNetworkEndpointGroup(zone string) ([]*computealpha.NetworkEndpointGroup, error) {
+	cloud.mu.Lock()
+	defer cloud.mu.Unlock()
+	return cloud.NetworkEndpointGroups[zone], nil
+}
+
+func (cloud *FakeNetworkEndpointGroupCloud) AggregatedListNetworkEndpointGroup() (map[string][]*computealpha.NetworkEndpointGroup, error) {
+	cloud.mu.Lock()
+	defer cloud.mu.Unlock()
+	return cloud.NetworkEndpointGroups, nil
+}
+
+func (cloud *FakeNetworkEndpointGroupCloud) CreateNetworkEndpointGroup(neg *computealpha.NetworkEndpointGroup, zone string) error {
+	cloud.mu.Lock()
+	defer cloud.mu.Unlock()
+	if _, ok := cloud.NetworkEndpointGroups[zone]; !ok {
+		cloud.NetworkEndpointGroups[zone] = []*computealpha.NetworkEndpointGroup{}
+	}
+	cloud.NetworkEndpointGroups[zone] = append(cloud.NetworkEndpointGroups[zone], neg)
+	cloud.NetworkEndpoints[networkEndpointKey(neg.Name, zone)] = []*computealpha.NetworkEndpoint{}
+	return nil
+}
+
+func (cloud *FakeNetworkEndpointGroupCloud) DeleteNetworkEndpointGroup(name string, zone string) error {
+	cloud.mu.Lock()
+	defer cloud.mu.Unlock()
+	delete(cloud.NetworkEndpoints, networkEndpointKey(name, zone))
+	negs := cloud.NetworkEndpointGroups[zone]
+	newList := []*computealpha.NetworkEndpointGroup{}
+	found := false
+	for _, neg := range negs {
+		if neg.Name == name {
+			found = true
+			continue
+		}
+		newList = append(newList, neg)
+	}
+	if !found {
+		return NotFoundError
+	}
+	cloud.NetworkEndpointGroups[zone] = newList
+	return nil
+}
+
+func (cloud *FakeNetworkEndpointGroupCloud) AttachNetworkEndpoints(name, zone string, endpoints []*computealpha.NetworkEndpoint) error {
+	cloud.mu.Lock()
+	defer cloud.mu.Unlock()
+	cloud.NetworkEndpoints[networkEndpointKey(name, zone)] = append(cloud.NetworkEndpoints[networkEndpointKey(name, zone)], endpoints...)
+	return nil
+}
+
+func (cloud *FakeNetworkEndpointGroupCloud) DetachNetworkEndpoints(name, zone string, endpoints []*computealpha.NetworkEndpoint) error {
+	cloud.mu.Lock()
+	defer cloud.mu.Unlock()
+	newList := []*computealpha.NetworkEndpoint{}
+	for _, ne := range cloud.NetworkEndpoints[networkEndpointKey(name, zone)] {
+		found := false
+		for _, remove := range endpoints {
+			if reflect.DeepEqual(*ne, *remove) {
+				found = true
+				break
+			}
+		}
+		if found {
+			continue
+		}
+		newList = append(newList, ne)
+	}
+	cloud.NetworkEndpoints[networkEndpointKey(name, zone)] = newList
+	return nil
+}
+
+func (cloud *FakeNetworkEndpointGroupCloud) ListNetworkEndpoints(name, zone string, showHealthStatus bool) ([]*computealpha.NetworkEndpointWithHealthStatus, error) {
+	cloud.mu.Lock()
+	defer cloud.mu.Unlock()
+	ret := []*computealpha.NetworkEndpointWithHealthStatus{}
+	nes, ok := cloud.NetworkEndpoints[networkEndpointKey(name, zone)]
+	if !ok {
+		return nil, NotFoundError
+	}
+	for _, ne := range nes {
+		ret = append(ret, &computealpha.NetworkEndpointWithHealthStatus{NetworkEndpoint: ne})
+	}
+	return ret, nil
+}
+
+func (cloud *FakeNetworkEndpointGroupCloud) NetworkURL() string {
+	return cloud.Network
+}
+
+func (cloud *FakeNetworkEndpointGroupCloud) SubnetworkURL() string {
+	return cloud.Subnetwork
+}
--- a/controllers/gce/networkendpointgroup/interfaces.go
+++ b/controllers/gce/networkendpointgroup/interfaces.go
@ -0,0 +1,66 @@
+/*
+Copyright 2017 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 networkendpointgroup
+
+import (
+	computealpha "google.golang.org/api/compute/v0.alpha"
+	"k8s.io/apimachinery/pkg/util/sets"
+)
+
+// NetworkEndpointGroupCloud is an interface for managing gce network endpoint group.
+type NetworkEndpointGroupCloud interface {
+	GetNetworkEndpointGroup(name string, zone string) (*computealpha.NetworkEndpointGroup, error)
+	ListNetworkEndpointGroup(zone string) ([]*computealpha.NetworkEndpointGroup, error)
+	AggregatedListNetworkEndpointGroup() (map[string][]*computealpha.NetworkEndpointGroup, error)
+	CreateNetworkEndpointGroup(neg *computealpha.NetworkEndpointGroup, zone string) error
+	DeleteNetworkEndpointGroup(name string, zone string) error
+	AttachNetworkEndpoints(name, zone string, endpoints []*computealpha.NetworkEndpoint) error
+	DetachNetworkEndpoints(name, zone string, endpoints []*computealpha.NetworkEndpoint) error
+	ListNetworkEndpoints(name, zone string, showHealthStatus bool) ([]*computealpha.NetworkEndpointWithHealthStatus, error)
+	NetworkURL() string
+	SubnetworkURL() string
+}
+
+// NetworkEndpointGroupNamer is an interface for generating network endpoint group name.
+type NetworkEndpointGroupNamer interface {
+	NEGName(namespace, name, port string) string
+	NEGPrefix() string
+}
+
+// ZoneGetter is an interface for retrieve zone related information
+type ZoneGetter interface {
+	ListZones() ([]string, error)
+	GetZoneForNode(name string) (string, error)
+}
+
+// Syncer is an interface to interact with syncer
+type Syncer interface {
+	Start() error
+	Stop()
+	Sync() bool
+	IsStopped() bool
+	IsShuttingDown() bool
+}
+
+// SyncerManager is an interface for controllers to manage Syncers
+type SyncerManager interface {
+	EnsureSyncer(namespace, name string, targetPorts sets.String) error
+	StopSyncer(namespace, name string)
+	Sync(namespace, name string)
+	GC() error
+	ShutDown()
+}
--- a/controllers/gce/networkendpointgroup/manager.go
+++ b/controllers/gce/networkendpointgroup/manager.go
@ -0,0 +1,256 @@
+/*
+Copyright 2017 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 networkendpointgroup
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/golang/glog"
+	utilerrors "k8s.io/apimachinery/pkg/util/errors"
+	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/client-go/tools/record"
+)
+
+// syncerManager exposes a few interfaces to manage syncer and ensures thread safety.
+type syncerManager struct {
+	namer      NetworkEndpointGroupNamer
+	recorder   record.EventRecorder
+	cloud      NetworkEndpointGroupCloud
+	zoneGetter ZoneGetter
+
+	serviceLister  cache.Indexer
+	endpointLister cache.Indexer
+
+	// TODO: lock per service instead of global lock
+	mu sync.Mutex
+	// svcPortMap is the canonical indicator for whether a service needs NEG
+	// key is service namespace/name, value is the list of target port that requires NEG
+	svcPortMap map[string]sets.String
+	// syncerMap stores the NEG syncer
+	// key is service namespace/name/targetPort. Value is the corresponding syncer
+	syncerMap map[string]Syncer
+}
+
+func newSyncerManager(namer NetworkEndpointGroupNamer, recorder record.EventRecorder, cloud NetworkEndpointGroupCloud, zoneGetter ZoneGetter, serviceLister cache.Indexer, endpointLister cache.Indexer) *syncerManager {
+	return &syncerManager{
+		namer:          namer,
+		recorder:       recorder,
+		cloud:          cloud,
+		zoneGetter:     zoneGetter,
+		serviceLister:  serviceLister,
+		endpointLister: endpointLister,
+		svcPortMap:     make(map[string]sets.String),
+		syncerMap:      make(map[string]Syncer),
+	}
+}
+
+// EnsureSyncer starts and stops syncers based on the input service ports.
+func (manager *syncerManager) EnsureSyncer(namespace, name string, targetPorts sets.String) error {
+	manager.mu.Lock()
+	defer manager.mu.Unlock()
+	key := serviceKeyFunc(namespace, name)
+	currentPorts, ok := manager.svcPortMap[key]
+	if !ok {
+		currentPorts = sets.NewString()
+	}
+
+	removes := currentPorts.Difference(targetPorts).List()
+	adds := targetPorts.Difference(currentPorts).List()
+	manager.svcPortMap[key] = targetPorts
+
+	// Stop syncer for removed ports
+	for _, port := range removes {
+		syncer, ok := manager.syncerMap[encodeSyncerKey(namespace, name, port)]
+		if ok {
+			syncer.Stop()
+		}
+	}
+
+	errList := []error{}
+	// Start syncer for added ports
+	for _, port := range adds {
+		syncer, ok := manager.syncerMap[encodeSyncerKey(namespace, name, port)]
+		if !ok {
+			syncer = newSyncer(
+				servicePort{
+					namespace:  namespace,
+					name:       name,
+					targetPort: port,
+				},
+				manager.namer.NEGName(namespace, name, port),
+				manager.recorder,
+				manager.cloud,
+				manager.zoneGetter,
+				manager.serviceLister,
+				manager.endpointLister,
+			)
+			manager.syncerMap[encodeSyncerKey(namespace, name, port)] = syncer
+		}
+
+		if syncer.IsStopped() {
+			if err := syncer.Start(); err != nil {
+				errList = append(errList, err)
+			}
+		}
+	}
+	return utilerrors.NewAggregate(errList)
+}
+
+// StopSyncer stops all syncers for the input service.
+func (manager *syncerManager) StopSyncer(namespace, name string) {
+	manager.mu.Lock()
+	defer manager.mu.Unlock()
+	key := serviceKeyFunc(namespace, name)
+	if ports, ok := manager.svcPortMap[key]; ok {
+		glog.V(2).Infof("Stopping NEG syncer for service %q", key)
+		for _, port := range ports.List() {
+			syncer, ok := manager.syncerMap[encodeSyncerKey(namespace, name, port)]
+			if ok {
+				syncer.Stop()
+			}
+		}
+		delete(manager.svcPortMap, key)
+	}
+	return
+}
+
+// Sync signals all syncers related to the service to sync.
+func (manager *syncerManager) Sync(namespace, name string) {
+	manager.mu.Lock()
+	defer manager.mu.Unlock()
+	key := serviceKeyFunc(namespace, name)
+	if portList, ok := manager.svcPortMap[key]; ok {
+		for _, port := range portList.List() {
+			if syncer, ok := manager.syncerMap[encodeSyncerKey(namespace, name, port)]; ok {
+				if !syncer.IsStopped() {
+					syncer.Sync()
+				}
+			}
+		}
+	}
+}
+
+// ShutDown signals all syncers to stop
+func (manager *syncerManager) ShutDown() {
+	manager.mu.Lock()
+	defer manager.mu.Unlock()
+	for _, s := range manager.syncerMap {
+		s.Stop()
+	}
+}
+
+// GC garbage collects syncers and NEGs.
+func (manager *syncerManager) GC() error {
+	glog.V(2).Infof("Start NEG garbage collection.")
+	defer glog.V(2).Infof("NEG garbage collection finished.")
+	// Garbage collect syncer
+	for _, key := range manager.getAllStoppedSyncerKeys().List() {
+		manager.garbageCollectSyncer(key)
+	}
+
+	// Garbage collect NEGs
+	if err := manager.garbageCollectNEG(); err != nil {
+		return fmt.Errorf("Failed to garbage collect negs: %v", err)
+	}
+	return nil
+}
+
+func (manager *syncerManager) garbageCollectSyncer(key string) {
+	manager.mu.Lock()
+	defer manager.mu.Unlock()
+	if manager.syncerMap[key].IsStopped() && !manager.syncerMap[key].IsShuttingDown() {
+		delete(manager.syncerMap, key)
+	}
+}
+
+func (manager *syncerManager) getAllStoppedSyncerKeys() sets.String {
+	manager.mu.Lock()
+	defer manager.mu.Unlock()
+	ret := sets.NewString()
+	for key, syncer := range manager.syncerMap {
+		if syncer.IsStopped() {
+			ret.Insert(key)
+		}
+	}
+	return ret
+}
+
+func (manager *syncerManager) garbageCollectNEG() error {
+	// Retrieve aggregated NEG list from cloud
+	// Compare against svcPortMap and Remove unintended NEGs by best effort
+	zoneNEGList, err := manager.cloud.AggregatedListNetworkEndpointGroup()
+	if err != nil {
+		return fmt.Errorf("failed to retrieve aggregated NEG list: %v", err)
+	}
+
+	negNames := sets.String{}
+	for _, list := range zoneNEGList {
+		for _, neg := range list {
+			if strings.HasPrefix(neg.Name, manager.namer.NEGPrefix()) {
+				negNames.Insert(neg.Name)
+			}
+		}
+	}
+
+	func() {
+		manager.mu.Lock()
+		defer manager.mu.Unlock()
+		for key, ports := range manager.svcPortMap {
+			namespace, name, err := cache.SplitMetaNamespaceKey(key)
+			if err != nil {
+				glog.Errorf("Failed to parse service key %q: %v", key, err)
+				continue
+			}
+			for _, port := range ports.List() {
+				name := manager.namer.NEGName(namespace, name, port)
+				negNames.Delete(name)
+			}
+		}
+	}()
+
+	// This section includes a potential race condition between deleting neg here and users adds the neg annotation.
+	// The worst outcome of the race condition is that neg is deleted in the end but user actually specifies a neg.
+	// This would be resolved (sync neg) when the next endpoint update or resync arrives.
+	// TODO: avoid race condition here
+	for zone := range zoneNEGList {
+		for _, name := range negNames.List() {
+			if err := manager.ensureDeleteNetworkEndpointGroup(name, zone); err != nil {
+				return fmt.Errorf("failed to delete NEG %q in %q: %v", name, zone, err)
+			}
+		}
+	}
+	return nil
+}
+
+// ensureDeleteNetworkEndpointGroup ensures neg is delete from zone
+func (manager *syncerManager) ensureDeleteNetworkEndpointGroup(name, zone string) error {
+	_, err := manager.cloud.GetNetworkEndpointGroup(name, zone)
+	if err != nil {
+		// Assume error is caused by not existing
+		return nil
+	}
+	glog.V(2).Infof("Deleting NEG %q in %q.", name, zone)
+	return manager.cloud.DeleteNetworkEndpointGroup(name, zone)
+}
+
+// encodeSyncerKey encodes a service namespace, name and targetPort into a string key
+func encodeSyncerKey(namespace, name, port string) string {
+	return fmt.Sprintf("%s||%s||%s", namespace, name, port)
+}
--- a/controllers/gce/networkendpointgroup/manager_test.go
+++ b/controllers/gce/networkendpointgroup/manager_test.go
@ -0,0 +1,187 @@
+/*
+Copyright 2017 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 networkendpointgroup
+
+import (
+	compute "google.golang.org/api/compute/v0.alpha"
+	apiv1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/kubernetes/fake"
+	"k8s.io/client-go/tools/record"
+	"k8s.io/ingress/controllers/gce/utils"
+	"testing"
+	"time"
+)
+
+const (
+	CluseterID = "clusterid"
+)
+
+func NewTestSyncerManager(kubeClient kubernetes.Interface) *syncerManager {
+	context := utils.NewControllerContext(kubeClient, apiv1.NamespaceAll, 1*time.Second, true)
+	manager := newSyncerManager(
+		utils.NewNamer(CluseterID, ""),
+		record.NewFakeRecorder(100),
+		NewFakeNetworkEndpointGroupCloud("test-subnetwork", "test-network"),
+		NewFakeZoneGetter(),
+		context.ServiceInformer.GetIndexer(),
+		context.EndpointInformer.GetIndexer(),
+	)
+	return manager
+}
+
+func TestEnsureAndStopSyncer(t *testing.T) {
+	testCases := []struct {
+		namespace string
+		name      string
+		ports     sets.String
+		stop      bool
+		expect    sets.String // keys of running syncers
+	}{
+		{
+			"ns1",
+			"n1",
+			sets.NewString("80", "443"),
+			false,
+			sets.NewString(
+				encodeSyncerKey("ns1", "n1", "80"),
+				encodeSyncerKey("ns1", "n1", "443"),
+			),
+		},
+		{
+			"ns1",
+			"n1",
+			sets.NewString("80", "namedport"),
+			false,
+			sets.NewString(
+				encodeSyncerKey("ns1", "n1", "80"),
+				encodeSyncerKey("ns1", "n1", "namedport"),
+			),
+		},
+		{
+			"ns2",
+			"n1",
+			sets.NewString("80"),
+			false,
+			sets.NewString(
+				encodeSyncerKey("ns1", "n1", "80"),
+				encodeSyncerKey("ns1", "n1", "namedport"),
+				encodeSyncerKey("ns2", "n1", "80"),
+			),
+		},
+		{
+			"ns1",
+			"n1",
+			sets.NewString(),
+			true,
+			sets.NewString(
+				encodeSyncerKey("ns2", "n1", "80"),
+			),
+		},
+	}
+
+	manager := NewTestSyncerManager(fake.NewSimpleClientset())
+	for _, tc := range testCases {
+		if tc.stop {
+			manager.StopSyncer(tc.namespace, tc.name)
+		} else {
+			if err := manager.EnsureSyncer(tc.namespace, tc.name, tc.ports); err != nil {
+				t.Errorf("Failed to ensure syncer %s/%s-%v: %v", tc.namespace, tc.name, tc.ports, err)
+			}
+		}
+
+		for _, key := range tc.expect.List() {
+			syncer, ok := manager.syncerMap[key]
+			if !ok {
+				t.Errorf("Expect syncer key %q to be present.", key)
+				continue
+			}
+			if syncer.IsStopped() || syncer.IsShuttingDown() {
+				t.Errorf("Expect syncer %q to be running.", key)
+			}
+		}
+		for key, syncer := range manager.syncerMap {
+			if tc.expect.Has(key) {
+				continue
+			}
+			if !syncer.IsStopped() {
+				t.Errorf("Expect syncer %q to be stopped.", key)
+			}
+		}
+	}
+
+	// make sure there is no leaking go routine
+	manager.StopSyncer("ns1", "n1")
+	manager.StopSyncer("ns2", "n1")
+}
+
+func TestGarbageCollectionSyncer(t *testing.T) {
+	manager := NewTestSyncerManager(fake.NewSimpleClientset())
+	if err := manager.EnsureSyncer("ns1", "n1", sets.NewString("80", "namedport")); err != nil {
+		t.Fatalf("Failed to ensure syncer: %v", err)
+	}
+	manager.StopSyncer("ns1", "n1")
+
+	syncer1 := manager.syncerMap[encodeSyncerKey("ns1", "n1", "80")]
+	syncer2 := manager.syncerMap[encodeSyncerKey("ns1", "n1", "namedport")]
+
+	if err := wait.PollImmediate(time.Second, 30*time.Second, func() (bool, error) {
+		return !syncer1.IsShuttingDown() && syncer1.IsStopped() && !syncer2.IsShuttingDown() && syncer2.IsStopped(), nil
+	}); err != nil {
+		t.Fatalf("Syncer failed to shutdown: %v", err)
+	}
+
+	if err := manager.GC(); err != nil {
+		t.Fatalf("Failed to GC: %v", err)
+	}
+
+	if len(manager.syncerMap) != 0 {
+		t.Fatalf("Expect 0 syncers left, but got %v", len(manager.syncerMap))
+	}
+}
+
+func TestGarbageCollectionNEG(t *testing.T) {
+	kubeClient := fake.NewSimpleClientset()
+	if _, err := kubeClient.Core().Endpoints(ServiceNamespace).Create(getDefaultEndpoint()); err != nil {
+		t.Fatalf("Failed to create endpoint: %v", err)
+	}
+	manager := NewTestSyncerManager(kubeClient)
+	if err := manager.EnsureSyncer(ServiceNamespace, ServiceName, sets.NewString("80")); err != nil {
+		t.Fatalf("Failed to ensure syncer: %v", err)
+	}
+
+	negName := manager.namer.NEGName("test", "test", "80")
+	manager.cloud.CreateNetworkEndpointGroup(&compute.NetworkEndpointGroup{
+		Name: negName,
+	}, TestZone1)
+
+	if err := manager.GC(); err != nil {
+		t.Fatalf("Failed to GC: %v", err)
+	}
+
+	negs, _ := manager.cloud.ListNetworkEndpointGroup(TestZone1)
+	for _, neg := range negs {
+		if neg.Name == negName {
+			t.Errorf("Expect NEG %q to be GCed.", negName)
+		}
+	}
+
+	// make sure there is no leaking go routine
+	manager.StopSyncer(ServiceNamespace, ServiceName)
+}
--- a/controllers/gce/networkendpointgroup/syncer.go
+++ b/controllers/gce/networkendpointgroup/syncer.go
@ -0,0 +1,524 @@
+/*
+Copyright 2017 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 networkendpointgroup
+
+import (
+	"fmt"
+	"math"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/golang/glog"
+	compute "google.golang.org/api/compute/v0.alpha"
+	apiv1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/clock"
+	utilerrors "k8s.io/apimachinery/pkg/util/errors"
+	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/client-go/tools/record"
+	"k8s.io/kubernetes/pkg/cloudprovider/providers/gce"
+)
+
+const (
+	MAX_NETWORK_ENDPOINTS_PER_BATCH = 500
+	minRetryDelay                   = 5 * time.Second
+	maxRetryDelay                   = 300 * time.Second
+)
+
+// servicePort includes information to uniquely identify a NEG
+type servicePort struct {
+	namespace string
+	name      string
+	// Serivice target port
+	targetPort string
+}
+
+// syncer handles synchorizing NEGs for one service port. It handles sync, resync and retry on error.
+type syncer struct {
+	servicePort
+	negName string
+
+	serviceLister  cache.Indexer
+	endpointLister cache.Indexer
+
+	recorder   record.EventRecorder
+	cloud      NetworkEndpointGroupCloud
+	zoneGetter ZoneGetter
+
+	stateLock    sync.Mutex
+	stopped      bool
+	shuttingDown bool
+
+	clock          clock.Clock
+	syncCh         chan interface{}
+	lastRetryDelay time.Duration
+	retryCount     int
+}
+
+func newSyncer(svcPort servicePort, networkEndpointGroupName string, recorder record.EventRecorder, cloud NetworkEndpointGroupCloud, zoneGetter ZoneGetter, serviceLister cache.Indexer, endpointLister cache.Indexer) *syncer {
+	glog.V(2).Infof("New syncer for service %s/%s port %s NEG %q", svcPort.namespace, svcPort.name, svcPort.targetPort, networkEndpointGroupName)
+	return &syncer{
+		servicePort:    svcPort,
+		negName:        networkEndpointGroupName,
+		recorder:       recorder,
+		serviceLister:  serviceLister,
+		cloud:          cloud,
+		endpointLister: endpointLister,
+		zoneGetter:     zoneGetter,
+		stopped:        true,
+		shuttingDown:   false,
+		clock:          clock.RealClock{},
+		lastRetryDelay: time.Duration(0),
+		retryCount:     0,
+	}
+}
+
+func (s *syncer) init() {
+	s.stateLock.Lock()
+	defer s.stateLock.Unlock()
+	s.stopped = false
+	s.syncCh = make(chan interface{}, 1)
+}
+
+// Start starts the syncer go routine if it has not been started.
+func (s *syncer) Start() error {
+	if !s.IsStopped() {
+		return fmt.Errorf("NEG syncer for %s/%s-%s is already running.", s.namespace, s.name, s.targetPort)
+	}
+	if s.IsShuttingDown() {
+		return fmt.Errorf("NEG syncer for %s/%s-%s is shutting down. ", s.namespace, s.name, s.targetPort)
+	}
+
+	glog.V(2).Infof("Starting NEG syncer for service port %s/%s-%s", s.namespace, s.name, s.targetPort)
+	s.init()
+	go func() {
+		for {
+			// equivalent to never retry
+			retryCh := make(<-chan time.Time)
+			err := s.sync()
+			if err != nil {
+				retryMesg := ""
+				if s.retryCount > maxRetries {
+					retryMesg = "(will not retry)"
+				} else {
+					retryCh = s.clock.After(s.nextRetryDelay())
+					retryMesg = "(will retry)"
+				}
+
+				if svc := getService(s.serviceLister, s.namespace, s.name); svc != nil {
+					s.recorder.Eventf(svc, apiv1.EventTypeWarning, "SyncNetworkEndpiontGroupFailed", "Failed to sync NEG %q %s: %v", s.negName, retryMesg, err)
+				}
+			} else {
+				s.resetRetryDelay()
+			}
+
+			select {
+			case _, open := <-s.syncCh:
+				if !open {
+					s.stateLock.Lock()
+					s.shuttingDown = false
+					s.stateLock.Unlock()
+					glog.V(2).Infof("Stopping NEG syncer for %s/%s-%s", s.namespace, s.name, s.targetPort)
+					return
+				}
+			case <-retryCh:
+				// continue to sync
+			}
+		}
+	}()
+	return nil
+}
+
+// Stop stops syncer and return only when syncer shutdown completes.
+func (s *syncer) Stop() {
+	s.stateLock.Lock()
+	defer s.stateLock.Unlock()
+	if !s.stopped {
+		s.stopped = true
+		s.shuttingDown = true
+		close(s.syncCh)
+	}
+}
+
+// Sync informs syncer to run sync loop as soon as possible.
+func (s *syncer) Sync() bool {
+	if s.IsStopped() {
+		glog.Warningf("NEG syncer for %s/%s-%s is already stopped.", s.namespace, s.name, s.targetPort)
+		return false
+	}
+	glog.V(2).Infof("=======Sync %s/%s-%s", s.namespace, s.name, s.targetPort)
+	select {
+	case s.syncCh <- struct{}{}:
+		return true
+	default:
+		return false
+	}
+}
+
+func (s *syncer) IsStopped() bool {
+	s.stateLock.Lock()
+	defer s.stateLock.Unlock()
+	return s.stopped
+}
+
+func (s *syncer) IsShuttingDown() bool {
+	s.stateLock.Lock()
+	defer s.stateLock.Unlock()
+	return s.shuttingDown
+}
+
+func (s *syncer) sync() error {
+	if s.IsStopped() || s.IsShuttingDown() {
+		glog.V(4).Infof("Skip syncing NEG %q for %s/%s-%s.", s.negName, s.namespace, s.name, s.targetPort)
+		return nil
+	}
+
+	glog.V(2).Infof("Sync NEG %q for %s/%s-%s", s.negName, s.namespace, s.name, s.targetPort)
+	ep, exists, err := s.endpointLister.Get(
+		&apiv1.Endpoints{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      s.name,
+				Namespace: s.namespace,
+			},
+		},
+	)
+	if err != nil {
+		return err
+	}
+
+	if !exists {
+		glog.Warningf("Endpoint %s/%s does not exists. Skipping NEG sync")
+		return nil
+	}
+
+	err = s.ensureNetworkEndpointGroups()
+	if err != nil {
+		return err
+	}
+
+	targetMap, err := s.toZoneNetworkEndpointMap(ep.(*apiv1.Endpoints))
+	if err != nil {
+		return err
+	}
+
+	currentMap, err := s.retrieveExistingZoneNetworkEndpointMap()
+	if err != nil {
+		return err
+	}
+
+	addEndpoints, removeEndpoints := calculateDifference(targetMap, currentMap)
+	if len(addEndpoints) == 0 && len(removeEndpoints) == 0 {
+		glog.V(4).Infof("No endpoint change for %s/%s, skip syncing NEG. ", s.namespace, s.name)
+		return nil
+	}
+
+	return s.syncNetworkEndpoints(addEndpoints, removeEndpoints)
+}
+
+// ensureNetworkEndpointGroups ensures negs are created in the related zones.
+func (s *syncer) ensureNetworkEndpointGroups() error {
+	var err error
+	zones, err := s.zoneGetter.ListZones()
+	if err != nil {
+		return err
+	}
+
+	var errList []error
+	for _, zone := range zones {
+		// Assume error is caused by not existing
+		neg, err := s.cloud.GetNetworkEndpointGroup(s.negName, zone)
+		if err != nil {
+			// Most likely to be caused by non-existed NEG
+			glog.V(4).Infof("Error while retriving %q in zone %q: %v", s.negName, zone, err)
+		}
+
+		needToCreate := false
+		if neg == nil {
+			needToCreate = true
+		} else if retrieveName(neg.LoadBalancer.Network) != retrieveName(s.cloud.NetworkURL()) ||
+			retrieveName(neg.LoadBalancer.Subnetwork) != retrieveName(s.cloud.SubnetworkURL()) {
+			// Only compare network and subnetwork names to avoid api endpoint differences that cause deleting NEG accidentally.
+			// TODO: change to compare network/subnetwork url instead of name when NEG API reach GA.
+			needToCreate = true
+			glog.V(2).Infof("NEG %q in %q does not match network and subnetwork of the cluster. Deleting NEG.", s.negName, zone)
+			err = s.cloud.DeleteNetworkEndpointGroup(s.negName, zone)
+			if err != nil {
+				errList = append(errList, err)
+			} else {
+				if svc := getService(s.serviceLister, s.namespace, s.name); svc != nil {
+					s.recorder.Eventf(svc, apiv1.EventTypeNormal, "Delete", "Deleted NEG %q for %s/%s-%s in %q.", s.negName, s.namespace, s.name, s.targetPort, zone)
+				}
+			}
+		}
+
+		if needToCreate {
+			glog.V(2).Infof("Creating NEG %q for %s/%s in %q.", s.negName, s.namespace, s.name, zone)
+			err = s.cloud.CreateNetworkEndpointGroup(&compute.NetworkEndpointGroup{
+				Name:                s.negName,
+				Type:                gce.NEGLoadBalancerType,
+				NetworkEndpointType: gce.NEGIPPortNetworkEndpointType,
+				LoadBalancer: &compute.NetworkEndpointGroupLbNetworkEndpointGroup{
+					Network:    s.cloud.NetworkURL(),
+					Subnetwork: s.cloud.SubnetworkURL(),
+				},
+			}, zone)
+			if err != nil {
+				errList = append(errList, err)
+			} else {
+				if svc := getService(s.serviceLister, s.namespace, s.name); svc != nil {
+					s.recorder.Eventf(svc, apiv1.EventTypeNormal, "Create", "Created NEG %q for %s/%s-%s in %q.", s.negName, s.namespace, s.name, s.targetPort, zone)
+				}
+			}
+		}
+	}
+	return utilerrors.NewAggregate(errList)
+}
+
+// toZoneNetworkEndpointMap translates addresses in endpoints object into zone and endpoints map
+func (s *syncer) toZoneNetworkEndpointMap(endpoints *apiv1.Endpoints) (map[string]sets.String, error) {
+	zoneNetworkEndpointMap := map[string]sets.String{}
+	targetPort, _ := strconv.Atoi(s.targetPort)
+	for _, subset := range endpoints.Subsets {
+		matchPort := ""
+		// service spec allows target port to be a named port.
+		// support both explicit port and named port.
+		for _, port := range subset.Ports {
+			if targetPort != 0 {
+				// targetPort is int
+				if int(port.Port) == targetPort {
+					matchPort = s.targetPort
+				}
+			} else {
+				// targetPort is string
+				if port.Name == s.targetPort {
+					matchPort = strconv.Itoa(int(port.Port))
+				}
+			}
+			if len(matchPort) > 0 {
+				break
+			}
+		}
+
+		// subset does not contain target port
+		if len(matchPort) == 0 {
+			continue
+		}
+		for _, address := range subset.Addresses {
+			zone, err := s.zoneGetter.GetZoneForNode(*address.NodeName)
+			if err != nil {
+				return nil, err
+			}
+			if zoneNetworkEndpointMap[zone] == nil {
+				zoneNetworkEndpointMap[zone] = sets.String{}
+			}
+			zoneNetworkEndpointMap[zone].Insert(encodeEndpoint(address.IP, *address.NodeName, matchPort))
+		}
+	}
+	return zoneNetworkEndpointMap, nil
+}
+
+// retrieveExistingZoneNetworkEndpointMap lists existing network endpoints in the neg and return the zone and endpoints map
+func (s *syncer) retrieveExistingZoneNetworkEndpointMap() (map[string]sets.String, error) {
+	zones, err := s.zoneGetter.ListZones()
+	if err != nil {
+		return nil, err
+	}
+
+	zoneNetworkEndpointMap := map[string]sets.String{}
+	for _, zone := range zones {
+		zoneNetworkEndpointMap[zone] = sets.String{}
+		networkEndpointsWithHealthStatus, err := s.cloud.ListNetworkEndpoints(s.negName, zone, false)
+		if err != nil {
+			return nil, err
+		}
+		for _, ne := range networkEndpointsWithHealthStatus {
+			zoneNetworkEndpointMap[zone].Insert(encodeEndpoint(ne.NetworkEndpoint.IpAddress, ne.NetworkEndpoint.Instance, strconv.FormatInt(ne.NetworkEndpoint.Port, 10)))
+		}
+	}
+	return zoneNetworkEndpointMap, nil
+}
+
+type ErrorList struct {
+	errList []error
+	lock    sync.Mutex
+}
+
+func (e *ErrorList) Add(err error) {
+	e.lock.Lock()
+	defer e.lock.Unlock()
+	e.errList = append(e.errList, err)
+}
+
+func (e *ErrorList) List() []error {
+	e.lock.Lock()
+	defer e.lock.Unlock()
+	return e.errList
+}
+
+// syncNetworkEndpoints adds and removes endpoints for negs
+func (s *syncer) syncNetworkEndpoints(addEndpoints, removeEndpoints map[string]sets.String) error {
+	var wg sync.WaitGroup
+	errList := &ErrorList{}
+
+	// Detach Endpoints
+	for zone, endpointSet := range removeEndpoints {
+		for {
+			if endpointSet.Len() == 0 {
+				break
+			}
+			networkEndpoints, err := s.toNetworkEndpointBatch(endpointSet)
+			if err != nil {
+				return err
+			}
+			s.detachNetworkEndpoints(&wg, zone, networkEndpoints, errList)
+		}
+	}
+
+	// Attach Endpoints
+	for zone, endpointSet := range addEndpoints {
+		for {
+			if endpointSet.Len() == 0 {
+				break
+			}
+			networkEndpoints, err := s.toNetworkEndpointBatch(endpointSet)
+			if err != nil {
+				return err
+			}
+			s.attachNetworkEndpoints(&wg, zone, networkEndpoints, errList)
+		}
+	}
+	wg.Wait()
+	return utilerrors.NewAggregate(errList.List())
+}
+
+// translate a endpoints set to a batch of network endpoints object
+func (s *syncer) toNetworkEndpointBatch(endpoints sets.String) ([]*compute.NetworkEndpoint, error) {
+	var ok bool
+	list := make([]string, int(math.Min(float64(endpoints.Len()), float64(MAX_NETWORK_ENDPOINTS_PER_BATCH))))
+	for i := range list {
+		list[i], ok = endpoints.PopAny()
+		if !ok {
+			break
+		}
+	}
+	networkEndpointList := make([]*compute.NetworkEndpoint, len(list))
+	for i, enc := range list {
+		ip, instance, port := decodeEndpoint(enc)
+		portNum, err := strconv.Atoi(port)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to decode endpoint %q: %v", enc, err)
+		}
+		networkEndpointList[i] = &compute.NetworkEndpoint{
+			Instance:  instance,
+			IpAddress: ip,
+			Port:      int64(portNum),
+		}
+	}
+	return networkEndpointList, nil
+}
+
+func (s *syncer) attachNetworkEndpoints(wg *sync.WaitGroup, zone string, networkEndpoints []*compute.NetworkEndpoint, errList *ErrorList) {
+	wg.Add(1)
+	go s.operationInternal(wg, zone, networkEndpoints, errList, s.cloud.AttachNetworkEndpoints, "Attach")
+}
+
+func (s *syncer) detachNetworkEndpoints(wg *sync.WaitGroup, zone string, networkEndpoints []*compute.NetworkEndpoint, errList *ErrorList) {
+	wg.Add(1)
+	go s.operationInternal(wg, zone, networkEndpoints, errList, s.cloud.DetachNetworkEndpoints, "Detach")
+}
+
+func (s *syncer) operationInternal(wg *sync.WaitGroup, zone string, networkEndpoints []*compute.NetworkEndpoint, errList *ErrorList, syncFunc func(name, zone string, endpoints []*compute.NetworkEndpoint) error, operationName string) {
+	defer wg.Done()
+	err := syncFunc(s.negName, zone, networkEndpoints)
+	if err != nil {
+		errList.Add(err)
+	}
+	if svc := getService(s.serviceLister, s.namespace, s.name); svc != nil {
+		if err == nil {
+			s.recorder.Eventf(svc, apiv1.EventTypeNormal, operationName, "%s %d network endpoints to NEG %q in %q.", operationName, len(networkEndpoints), s.negName, zone)
+		} else {
+			s.recorder.Eventf(svc, apiv1.EventTypeWarning, operationName+"Failed", "Failed to %s %d network endpoints to NEG %q in %q: %v", operationName, len(networkEndpoints), s.negName, zone, err)
+		}
+	}
+}
+
+func (s *syncer) nextRetryDelay() time.Duration {
+	s.retryCount += 1
+	s.lastRetryDelay *= 2
+	if s.lastRetryDelay < minRetryDelay {
+		s.lastRetryDelay = minRetryDelay
+	} else if s.lastRetryDelay > maxRetryDelay {
+		s.lastRetryDelay = maxRetryDelay
+	}
+	return s.lastRetryDelay
+}
+
+func (s *syncer) resetRetryDelay() {
+	s.retryCount = 0
+	s.lastRetryDelay = time.Duration(0)
+}
+
+// encodeEndpoint encodes ip and instance into a single string
+func encodeEndpoint(ip, instance, port string) string {
+	return fmt.Sprintf("%s||%s||%s", ip, instance, port)
+}
+
+// decodeEndpoint decodes ip and instance from an encoded string
+func decodeEndpoint(str string) (string, string, string) {
+	strs := strings.Split(str, "||")
+	return strs[0], strs[1], strs[2]
+}
+
+// calculateDifference determines what endpoints needs to be added and removed in order to move current state to target state.
+func calculateDifference(targetMap, currentMap map[string]sets.String) (map[string]sets.String, map[string]sets.String) {
+	addSet := map[string]sets.String{}
+	removeSet := map[string]sets.String{}
+	for zone, endpointSet := range targetMap {
+		diff := endpointSet.Difference(currentMap[zone])
+		if len(diff) > 0 {
+			addSet[zone] = diff
+		}
+	}
+
+	for zone, endpointSet := range currentMap {
+		diff := endpointSet.Difference(targetMap[zone])
+		if len(diff) > 0 {
+			removeSet[zone] = diff
+		}
+	}
+	return addSet, removeSet
+}
+
+func retrieveName(url string) string {
+	strs := strings.Split(url, "/")
+	return strs[len(strs)-1]
+}
+
+// getService retrieves service object from serviceLister based on the input namespace and name
+func getService(serviceLister cache.Indexer, namespace, name string) *apiv1.Service {
+	service, exists, err := serviceLister.GetByKey(serviceKeyFunc(namespace, name))
+	if exists && err == nil {
+		return service.(*apiv1.Service)
+	}
+	if err != nil {
+		glog.Errorf("Failed to retrieve service %s/%s from store: %v", namespace, name, err)
+	}
+	return nil
+}
--- a/controllers/gce/networkendpointgroup/syncer_test.go
+++ b/controllers/gce/networkendpointgroup/syncer_test.go
@ -0,0 +1,439 @@
+package networkendpointgroup
+
+import (
+	apiv1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/sets"
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/kubernetes/fake"
+	"k8s.io/client-go/tools/record"
+	"k8s.io/ingress/controllers/gce/utils"
+	"reflect"
+	"testing"
+	"time"
+)
+
+const (
+	NegName          = "test-neg-name"
+	ServiceNamespace = "test-ns"
+	ServiceName      = "test-name"
+	NamedPort        = "named-port"
+)
+
+func NewTestSyncer() *syncer {
+	kubeClient := fake.NewSimpleClientset()
+	context := utils.NewControllerContext(kubeClient, apiv1.NamespaceAll, 1*time.Second, true)
+	svcPort := servicePort{
+		namespace:  ServiceNamespace,
+		name:       ServiceName,
+		targetPort: "80",
+	}
+
+	return newSyncer(svcPort,
+		NegName,
+		record.NewFakeRecorder(100),
+		NewFakeNetworkEndpointGroupCloud("test-subnetwork", "test-newtork"),
+		NewFakeZoneGetter(),
+		context.ServiceInformer.GetIndexer(),
+		context.EndpointInformer.GetIndexer())
+}
+
+func TestStartAndStopSyncer(t *testing.T) {
+	syncer := NewTestSyncer()
+	if !syncer.IsStopped() {
+		t.Fatalf("Syncer is not stopped after creation.")
+	}
+	if syncer.IsShuttingDown() {
+		t.Fatalf("Syncer is shutting down after creation.")
+	}
+
+	if err := syncer.Start(); err != nil {
+		t.Fatalf("Failed to start syncer: %v", err)
+	}
+	if syncer.IsStopped() {
+		t.Fatalf("Syncer is stopped after Start.")
+	}
+	if syncer.IsShuttingDown() {
+		t.Fatalf("Syncer is shutting down after Start.")
+	}
+
+	syncer.Stop()
+	if !syncer.IsStopped() {
+		t.Fatalf("Syncer is not stopped after Stop.")
+	}
+
+	if err := wait.PollImmediate(time.Second, 30*time.Second, func() (bool, error) {
+		return !syncer.IsShuttingDown() && syncer.IsStopped(), nil
+	}); err != nil {
+		t.Fatalf("Syncer failed to shutdown: %v", err)
+	}
+
+	if err := syncer.Start(); err != nil {
+		t.Fatalf("Failed to restart syncer: %v", err)
+	}
+	if syncer.IsStopped() {
+		t.Fatalf("Syncer is stopped after restart.")
+	}
+	if syncer.IsShuttingDown() {
+		t.Fatalf("Syncer is shutting down after restart.")
+	}
+
+	syncer.Stop()
+	if !syncer.IsStopped() {
+		t.Fatalf("Syncer is not stopped after Stop.")
+	}
+}
+
+func TestEnsureNetworkEndpointGroups(t *testing.T) {
+	syncer := NewTestSyncer()
+	if err := syncer.ensureNetworkEndpointGroups(); err != nil {
+		t.Errorf("Failed to ensure NEGs: %v", err)
+	}
+
+	ret, _ := syncer.cloud.AggregatedListNetworkEndpointGroup()
+	expectZones := []string{TestZone1, TestZone2}
+	for _, zone := range expectZones {
+		negs, ok := ret[zone]
+		if !ok {
+			t.Errorf("Failed to find zone %q from ret %v", zone, ret)
+			continue
+		}
+
+		if len(negs) != 1 {
+			t.Errorf("Unexpected negs %v", negs)
+		} else {
+			if negs[0].Name != NegName {
+				t.Errorf("Unexpected neg %q", negs[0].Name)
+			}
+		}
+	}
+}
+
+func TestToZoneNetworkEndpointMap(t *testing.T) {
+	syncer := NewTestSyncer()
+	testCases := []struct {
+		targetPort string
+		expect     map[string]sets.String
+	}{
+		{
+			targetPort: "80",
+			expect: map[string]sets.String{
+				TestZone1: sets.NewString("10.100.1.1||instance1||80", "10.100.1.2||instance1||80", "10.100.2.1||instance2||80"),
+				TestZone2: sets.NewString("10.100.3.1||instance3||80"),
+			},
+		},
+		{
+			targetPort: NamedPort,
+			expect: map[string]sets.String{
+				TestZone1: sets.NewString("10.100.2.2||instance2||81"),
+				TestZone2: sets.NewString("10.100.4.1||instance4||81", "10.100.3.2||instance3||8081", "10.100.4.2||instance4||8081"),
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		syncer.targetPort = tc.targetPort
+		res, _ := syncer.toZoneNetworkEndpointMap(getDefaultEndpoint())
+
+		if !reflect.DeepEqual(res, tc.expect) {
+			t.Errorf("Expect %v, but got %v.", tc.expect, res)
+		}
+	}
+}
+
+func TestEncodeDecodeEndpoint(t *testing.T) {
+	ip := "10.0.0.10"
+	instance := "somehost"
+	port := "8080"
+
+	retIp, retInstance, retPort := decodeEndpoint(encodeEndpoint(ip, instance, port))
+
+	if ip != retIp || instance != retInstance || retPort != port {
+		t.Fatalf("Encode and decode endpoint failed. Expect %q, %q, %q but got %q, %q, %q.", ip, instance, port, retIp, retInstance, retPort)
+	}
+}
+
+func TestCalculateDifference(t *testing.T) {
+	testCases := []struct {
+		targetSet  map[string]sets.String
+		currentSet map[string]sets.String
+		addSet     map[string]sets.String
+		removeSet  map[string]sets.String
+	}{
+		// unchanged
+		{
+			targetSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+			},
+			currentSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+			},
+			addSet:    map[string]sets.String{},
+			removeSet: map[string]sets.String{},
+		},
+		// unchanged
+		{
+			targetSet:  map[string]sets.String{},
+			currentSet: map[string]sets.String{},
+			addSet:     map[string]sets.String{},
+			removeSet:  map[string]sets.String{},
+		},
+		// add in one zone
+		{
+			targetSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+			},
+			currentSet: map[string]sets.String{},
+			addSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+			},
+			removeSet: map[string]sets.String{},
+		},
+		// add in 2 zones
+		{
+			targetSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+				TestZone2: sets.NewString("e", "f", "g"),
+			},
+			currentSet: map[string]sets.String{},
+			addSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+				TestZone2: sets.NewString("e", "f", "g"),
+			},
+			removeSet: map[string]sets.String{},
+		},
+		// remove in one zone
+		{
+			targetSet: map[string]sets.String{},
+			currentSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+			},
+			addSet: map[string]sets.String{},
+			removeSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+			},
+		},
+		// remove in 2 zones
+		{
+			targetSet: map[string]sets.String{},
+			currentSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+				TestZone2: sets.NewString("e", "f", "g"),
+			},
+			addSet: map[string]sets.String{},
+			removeSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+				TestZone2: sets.NewString("e", "f", "g"),
+			},
+		},
+		// add and delete in one zone
+		{
+			targetSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+			},
+			currentSet: map[string]sets.String{
+				TestZone1: sets.NewString("b", "c", "d"),
+			},
+			addSet: map[string]sets.String{
+				TestZone1: sets.NewString("a"),
+			},
+			removeSet: map[string]sets.String{
+				TestZone1: sets.NewString("d"),
+			},
+		},
+		// add and delete in 2 zones
+		{
+			targetSet: map[string]sets.String{
+				TestZone1: sets.NewString("a", "b", "c"),
+				TestZone2: sets.NewString("a", "b", "c"),
+			},
+			currentSet: map[string]sets.String{
+				TestZone1: sets.NewString("b", "c", "d"),
+				TestZone2: sets.NewString("b", "c", "d"),
+			},
+			addSet: map[string]sets.String{
+				TestZone1: sets.NewString("a"),
+				TestZone2: sets.NewString("a"),
+			},
+			removeSet: map[string]sets.String{
+				TestZone1: sets.NewString("d"),
+				TestZone2: sets.NewString("d"),
+			},
+		},
+	}
+
+	for _, tc := range testCases {
+		addSet, removeSet := calculateDifference(tc.targetSet, tc.currentSet)
+
+		if !reflect.DeepEqual(addSet, tc.addSet) {
+			t.Errorf("Failed to calculate difference for add, expecting %v, but got %v", tc.addSet, addSet)
+		}
+
+		if !reflect.DeepEqual(removeSet, tc.removeSet) {
+			t.Errorf("Failed to calculate difference for remove, expecting %v, but got %v", tc.removeSet, removeSet)
+		}
+	}
+}
+
+func TestSyncNetworkEndpoints(t *testing.T) {
+	syncer := NewTestSyncer()
+	if err := syncer.ensureNetworkEndpointGroups(); err != nil {
+		t.Fatalf("Failed to ensure NEG: %v", err)
+	}
+
+	testCases := []struct {
+		expectSet map[string]sets.String
+		addSet    map[string]sets.String
+		removeSet map[string]sets.String
+	}{
+		{
+			expectSet: map[string]sets.String{
+				TestZone1: sets.NewString("10.100.1.1||instance1||80", "10.100.2.1||instance2||80"),
+				TestZone2: sets.NewString("10.100.3.1||instance3||80", "10.100.4.1||instance4||80"),
+			},
+			addSet: map[string]sets.String{
+				TestZone1: sets.NewString("10.100.1.1||instance1||80", "10.100.2.1||instance2||80"),
+				TestZone2: sets.NewString("10.100.3.1||instance3||80", "10.100.4.1||instance4||80"),
+			},
+			removeSet: map[string]sets.String{},
+		},
+		{
+			expectSet: map[string]sets.String{
+				TestZone1: sets.NewString("10.100.1.2||instance1||80"),
+				TestZone2: sets.NewString(),
+			},
+			addSet: map[string]sets.String{
+				TestZone1: sets.NewString("10.100.1.2||instance1||80"),
+			},
+			removeSet: map[string]sets.String{
+				TestZone1: sets.NewString("10.100.1.1||instance1||80", "10.100.2.1||instance2||80"),
+				TestZone2: sets.NewString("10.100.3.1||instance3||80", "10.100.4.1||instance4||80"),
+			},
+		},
+		{
+			expectSet: map[string]sets.String{
+				TestZone1: sets.NewString("10.100.1.2||instance1||80"),
+				TestZone2: sets.NewString("10.100.3.2||instance3||80"),
+			},
+			addSet: map[string]sets.String{
+				TestZone2: sets.NewString("10.100.3.2||instance3||80"),
+			},
+			removeSet: map[string]sets.String{},
+		},
+	}
+
+	for _, tc := range testCases {
+		if err := syncer.syncNetworkEndpoints(tc.addSet, tc.removeSet); err != nil {
+			t.Fatalf("Failed to sync network endpoints: %v", err)
+		}
+		examineNetworkEndpoints(tc.expectSet, syncer, t)
+	}
+}
+
+func examineNetworkEndpoints(expectSet map[string]sets.String, syncer *syncer, t *testing.T) {
+	for zone, endpoints := range expectSet {
+		expectEndpoints, err := syncer.toNetworkEndpointBatch(endpoints)
+		if err != nil {
+			t.Fatalf("Failed to convert endpoints to network endpoints: %v", err)
+		}
+		if cloudEndpoints, err := syncer.cloud.ListNetworkEndpoints(syncer.negName, zone, false); err == nil {
+			if len(expectEndpoints) != len(cloudEndpoints) {
+				t.Errorf("Expect number of endpoints to be %v, but got %v.", len(expectEndpoints), len(cloudEndpoints))
+			}
+			for _, expectEp := range expectEndpoints {
+				found := false
+				for _, cloudEp := range cloudEndpoints {
+					if reflect.DeepEqual(*expectEp, *cloudEp.NetworkEndpoint) {
+						found = true
+						break
+					}
+				}
+				if !found {
+					t.Errorf("Endpoint %v not found.", expectEp)
+				}
+			}
+		} else {
+			t.Errorf("Failed to list network endpoints in zone %q: %v.", zone, err)
+		}
+	}
+}
+
+func getDefaultEndpoint() *apiv1.Endpoints {
+	instance1 := TestInstance1
+	instance2 := TestInstance2
+	instance3 := TestInstance3
+	instance4 := TestInstance4
+	return &apiv1.Endpoints{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      ServiceName,
+			Namespace: ServiceNamespace,
+		},
+		Subsets: []apiv1.EndpointSubset{
+			{
+				Addresses: []apiv1.EndpointAddress{
+					{
+						IP:       "10.100.1.1",
+						NodeName: &instance1,
+					},
+					{
+						IP:       "10.100.1.2",
+						NodeName: &instance1,
+					},
+					{
+						IP:       "10.100.2.1",
+						NodeName: &instance2,
+					},
+					{
+						IP:       "10.100.3.1",
+						NodeName: &instance3,
+					},
+				},
+				Ports: []apiv1.EndpointPort{
+					{
+						Name:     "",
+						Port:     int32(80),
+						Protocol: apiv1.ProtocolTCP,
+					},
+				},
+			},
+			{
+				Addresses: []apiv1.EndpointAddress{
+					{
+						IP:       "10.100.2.2",
+						NodeName: &instance2,
+					},
+					{
+						IP:       "10.100.4.1",
+						NodeName: &instance4,
+					},
+				},
+				Ports: []apiv1.EndpointPort{
+					{
+						Name:     NamedPort,
+						Port:     int32(81),
+						Protocol: apiv1.ProtocolTCP,
+					},
+				},
+			},
+			{
+				Addresses: []apiv1.EndpointAddress{
+					{
+						IP:       "10.100.3.2",
+						NodeName: &instance3,
+					},
+					{
+						IP:       "10.100.4.2",
+						NodeName: &instance4,
+					},
+				},
+				Ports: []apiv1.EndpointPort{
+					{
+						Name:     NamedPort,
+						Port:     int32(8081),
+						Protocol: apiv1.ProtocolTCP,
+					},
+				},
+			},
+		},
+	}
+}