Allow specifying traffic distribution preference for the etcd client …

…Service (#973)

* Allow specifying traffic distribution preference for the etcd client Service

api/v1alpha1/etcd.go

@@ -243,6 +243,11 @@ type ClientService struct {
 	// Labels specify the labels that should be added to the client service
 	// +optional
 	Labels map[string]string `json:"labels,omitempty"`
+	// TrafficDistribution defines the traffic distribution preference that should be added to the client service.
+	// More info: https://kubernetes.io/docs/reference/networking/virtual-ips/#traffic-distribution
+	// +optional
+	// +kubebuilder:validation:Enum=PreferClose
+	TrafficDistribution *string `json:"trafficDistribution,omitempty"`
 }
 
 // SharedConfig defines parameters shared and used by Etcd as well as backup-restore sidecar.

charts/druid/charts/crds/templates/crd-druid.gardener.cloud_etcds.yaml

@@ -404,6 +404,13 @@ spec:
                         description: Labels specify the labels that should be added
                           to the client service
                         type: object
+                      trafficDistribution:
+                        description: |-
+                          TrafficDistribution defines the traffic distribution preference that should be added to the client service.
+                          More info: https://kubernetes.io/docs/reference/networking/virtual-ips/#traffic-distribution
+                        enum:
+                        - PreferClose
+                        type: string
                     type: object
                   clientUrlTls:
                     description: ClientUrlTLS contains the ca, server TLS and client

config/crd/bases/crd-druid.gardener.cloud_etcds.yaml

@@ -404,6 +404,13 @@ spec:
                         description: Labels specify the labels that should be added
                           to the client service
                         type: object
+                      trafficDistribution:
+                        description: |-
+                          TrafficDistribution defines the traffic distribution preference that should be added to the client service.
+                          More info: https://kubernetes.io/docs/reference/networking/virtual-ips/#traffic-distribution
+                        enum:
+                        - PreferClose
+                        type: string
                     type: object
                   clientUrlTls:
                     description: ClientUrlTLS contains the ca, server TLS and client

config/samples/druid_v1alpha1_etcd.yaml

@@ -36,6 +36,12 @@ spec:
     serverPort: 2380
     quota: 8Gi
     # heartbeatDuration: 10s
+    # clientService:
+    #   annotations:
+    #     key: value
+    #   labels:
+    #     key: value
+    #   trafficDistribution: PreferClose
   backup:
     port: 8080
     fullSnapshotSchedule: "0 */24 * * *"

config/samples/druid_v1alpha1_etcd_azurite.yaml

@@ -36,6 +36,12 @@ spec:
     serverPort: 2380
     quota: 8Gi
     # heartbeatDuration: 10s
+    # clientService:
+    #   annotations:
+    #     key: value
+    #   labels:
+    #     key: value
+    #   trafficDistribution: PreferClose
   backup:
     port: 8080
     fullSnapshotSchedule: "0 */24 * * *"

config/samples/druid_v1alpha1_etcd_fakegcs.yaml

@@ -36,6 +36,12 @@ spec:
     serverPort: 2380
     quota: 8Gi
     # heartbeatDuration: 10s
+    # clientService:
+    #   annotations:
+    #     key: value
+    #   labels:
+    #     key: value
+    #   trafficDistribution: PreferClose
   backup:
     port: 8080
     fullSnapshotSchedule: "0 */24 * * *"

config/samples/druid_v1alpha1_etcd_localstack.yaml

@@ -36,6 +36,12 @@ spec:
     serverPort: 2380
     quota: 8Gi
     # heartbeatDuration: 10s
+    # clientService:
+    #   annotations:
+    #     key: value
+    #   labels:
+    #     key: value
+    #   trafficDistribution: PreferClose
   backup:
     port: 8080
     fullSnapshotSchedule: "0 */24 * * *"

docs/api-reference/etcd-druid-api.md

@@ -61,6 +61,7 @@ _Appears in:_
 | --- | --- | --- | --- |
 | `annotations` _object (keys:string, values:string)_ | Annotations specify the annotations that should be added to the client service |  |  |
 | `labels` _object (keys:string, values:string)_ | Labels specify the labels that should be added to the client service |  |  |
+| `trafficDistribution` _string_ | TrafficDistribution defines the traffic distribution preference that should be added to the client service.<br />More info: https://kubernetes.io/docs/reference/networking/virtual-ips/#traffic-distribution |  | Enum: [PreferClose] <br /> |
 
 
 #### CompactionMode

internal/component/clientservice/clientservice.go

@@ -115,6 +115,7 @@ func buildResource(etcd *druidv1alpha1.Etcd, svc *corev1.Service) {
 	// Therefore, only using default labels as label selector can cause issues as we have already seen in https://github.com/gardener/etcd-druid/issues/914
 	svc.Spec.Selector = utils.MergeMaps(druidv1alpha1.GetDefaultLabels(etcd.ObjectMeta), map[string]string{druidv1alpha1.LabelComponentKey: common.ComponentNameStatefulSet})
 	svc.Spec.Ports = getPorts(etcd)
+	svc.Spec.TrafficDistribution = getTrafficDistribution(etcd)
 }
 
 func getObjectKey(obj metav1.ObjectMeta) client.ObjectKey {
@@ -144,6 +145,13 @@ func getAnnotations(etcd *druidv1alpha1.Etcd) map[string]string {
 	return nil
 }
 
+func getTrafficDistribution(etcd *druidv1alpha1.Etcd) *string {
+	if etcd.Spec.Etcd.ClientService != nil {
+		return etcd.Spec.Etcd.ClientService.TrafficDistribution
+	}
+	return nil
+}
+
 func emptyClientService(objectKey client.ObjectKey) *corev1.Service {
 	return &corev1.Service{
 		ObjectMeta: metav1.ObjectMeta{

internal/component/clientservice/clientservice_test.go

@@ -84,12 +84,13 @@ func TestGetExistingResourceNames(t *testing.T) {
 // ----------------------------------- Sync -----------------------------------
 func TestSyncWhenNoServiceExists(t *testing.T) {
 	testCases := []struct {
-		name        string
-		clientPort  *int32
-		backupPort  *int32
-		peerPort    *int32
-		createErr   *apierrors.StatusError
-		expectedErr *druiderr.DruidError
+		name                string
+		clientPort          *int32
+		backupPort          *int32
+		peerPort            *int32
+		trafficDistribution *string
+		createErr           *apierrors.StatusError
+		expectedErr         *druiderr.DruidError
 	}{
 		{
 			name: "create client service with default ports",
@@ -100,6 +101,10 @@ func TestSyncWhenNoServiceExists(t *testing.T) {
 			backupPort: ptr.To[int32](3333),
 			peerPort:   ptr.To[int32](4444),
 		},
+		{
+			name:                "create client service with traffic distribution",
+			trafficDistribution: ptr.To("PreferClose"),
+		},
 		{
 			name:      "create fails when there is a create error",
 			createErr: testutils.TestAPIInternalErr,
@@ -115,7 +120,7 @@ func TestSyncWhenNoServiceExists(t *testing.T) {
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
 			t.Parallel()
-			etcd := buildEtcd(tc.clientPort, tc.peerPort, tc.backupPort)
+			etcd := buildEtcd(tc.clientPort, tc.peerPort, tc.backupPort, tc.trafficDistribution)
 			cl := testutils.CreateTestFakeClientForObjects(nil, tc.createErr, nil, nil, nil, client.ObjectKey{Name: druidv1alpha1.GetClientServiceName(etcd.ObjectMeta), Namespace: etcd.Namespace})
 			operator := New(cl)
 			opCtx := component.NewOperatorContext(context.Background(), logr.Discard(), uuid.NewString())
@@ -134,24 +139,30 @@ func TestSyncWhenNoServiceExists(t *testing.T) {
 
 func TestSyncWhenServiceExists(t *testing.T) {
 	const (
-		originalClientPort int32 = 2379
-		originalServerPort int32 = 2380
-		originalBackupPort int32 = 8080
+		originalClientPort          int32  = 2379
+		originalServerPort          int32  = 2380
+		originalBackupPort          int32  = 8080
+		originalTrafficDistribution string = "PreferClose"
 	)
-	existingEtcd := buildEtcd(ptr.To(originalClientPort), ptr.To(originalServerPort), ptr.To(originalBackupPort))
+	existingEtcd := buildEtcd(ptr.To(originalClientPort), ptr.To(originalServerPort), ptr.To(originalBackupPort), ptr.To(originalTrafficDistribution))
 	testCases := []struct {
-		name          string
-		clientPort    *int32
-		backupPort    *int32
-		peerPort      *int32
-		patchErr      *apierrors.StatusError
-		expectedError *druiderr.DruidError
+		name                string
+		clientPort          *int32
+		backupPort          *int32
+		peerPort            *int32
+		trafficDistribution *string
+		patchErr            *apierrors.StatusError
+		expectedError       *druiderr.DruidError
 	}{
 		{
 			name:       "update peer service with new server port",
 			clientPort: ptr.To[int32](2222),
 			peerPort:   ptr.To[int32](3333),
 		},
+		{
+			name:                "update client service with new traffic distribution",
+			trafficDistribution: ptr.To("Foo"),
+		},
 		{
 			name:       "update fails when there is a patch error",
 			clientPort: ptr.To[int32](2222),
@@ -173,7 +184,7 @@ func TestSyncWhenServiceExists(t *testing.T) {
 			// ********************* test sync with updated ports *********************
 			operator := New(cl)
 			opCtx := component.NewOperatorContext(context.Background(), logr.Discard(), uuid.NewString())
-			updatedEtcd := buildEtcd(tc.clientPort, tc.peerPort, tc.backupPort)
+			updatedEtcd := buildEtcd(tc.clientPort, tc.peerPort, tc.backupPort, tc.trafficDistribution)
 			syncErr := operator.Sync(opCtx, updatedEtcd)
 			latestClientSvc, getErr := getLatestClientService(cl, updatedEtcd)
 			g.Expect(latestClientSvc).ToNot(BeNil())
@@ -247,7 +258,7 @@ func TestTriggerDelete(t *testing.T) {
 }
 
 // ---------------------------- Helper Functions -----------------------------
-func buildEtcd(clientPort, peerPort, backupPort *int32) *druidv1alpha1.Etcd {
+func buildEtcd(clientPort, peerPort, backupPort *int32, trafficDistribution *string) *druidv1alpha1.Etcd {
 	etcdBuilder := testutils.EtcdBuilderWithDefaults(testutils.TestEtcdName, testutils.TestNamespace)
 	if clientPort != nil {
 		etcdBuilder.WithEtcdClientPort(clientPort)
@@ -258,6 +269,9 @@ func buildEtcd(clientPort, peerPort, backupPort *int32) *druidv1alpha1.Etcd {
 	if backupPort != nil {
 		etcdBuilder.WithBackupPort(backupPort)
 	}
+	if trafficDistribution != nil {
+		etcdBuilder.WithEtcdClientServiceTrafficDistribution(trafficDistribution)
+	}
 	return etcdBuilder.Build()
 }
 
@@ -268,9 +282,11 @@ func matchClientService(g *WithT, etcd *druidv1alpha1.Etcd, actualSvc corev1.Ser
 	etcdObjMeta := etcd.ObjectMeta
 	expectedLabels := druidv1alpha1.GetDefaultLabels(etcdObjMeta)
 	var expectedAnnotations map[string]string
+	var expectedTrafficDistribution *string
 	if etcd.Spec.Etcd.ClientService != nil {
 		expectedAnnotations = etcd.Spec.Etcd.ClientService.Annotations
 		expectedLabels = utils.MergeMaps(etcd.Spec.Etcd.ClientService.Labels, druidv1alpha1.GetDefaultLabels(etcdObjMeta))
+		expectedTrafficDistribution = etcd.Spec.Etcd.ClientService.TrafficDistribution
 	}
 	expectedLabelSelector := utils.MergeMaps(druidv1alpha1.GetDefaultLabels(etcdObjMeta), map[string]string{druidv1alpha1.LabelComponentKey: common.ComponentNameStatefulSet})
 
@@ -306,6 +322,7 @@ func matchClientService(g *WithT, etcd *druidv1alpha1.Etcd, actualSvc corev1.Ser
 					TargetPort: intstr.FromInt(int(backupPort)),
 				}),
 			),
+			"TrafficDistribution": Equal(expectedTrafficDistribution),
 		}),
 	}))
 }

test/utils/etcd.go

@@ -278,6 +278,19 @@ func (eb *EtcdBuilder) WithEtcdClientServiceAnnotations(annotations map[string]s
 	return eb
 }
 
+func (eb *EtcdBuilder) WithEtcdClientServiceTrafficDistribution(trafficDistribution *string) *EtcdBuilder {
+	if eb == nil || eb.etcd == nil {
+		return nil
+	}
+
+	if eb.etcd.Spec.Etcd.ClientService == nil {
+		eb.etcd.Spec.Etcd.ClientService = &druidv1alpha1.ClientService{}
+	}
+
+	eb.etcd.Spec.Etcd.ClientService.TrafficDistribution = trafficDistribution
+	return eb
+}
+
 func (eb *EtcdBuilder) WithEtcdServerPort(serverPort *int32) *EtcdBuilder {
 	if eb == nil || eb.etcd == nil {
 		return nil