Implement the EndpointSlice controller side of PreferSameZone/PreferSameNode

pkg/controller/endpointslice/endpointslice_controller.go

@@ -186,7 +186,7 @@ func NewController(ctx context.Context, podInformer coreinformers.PodInformer,
 		c.topologyCache,
 		c.eventRecorder,
 		ControllerName,
-		endpointslicerec.WithTrafficDistributionEnabled(utilfeature.DefaultFeatureGate.Enabled(features.ServiceTrafficDistribution)),
+		endpointslicerec.WithTrafficDistributionEnabled(utilfeature.DefaultFeatureGate.Enabled(features.ServiceTrafficDistribution), utilfeature.DefaultFeatureGate.Enabled(features.PreferSameTrafficDistribution)),
 	)
 
 	return c

staging/src/k8s.io/endpointslice/metrics/metrics.go

@@ -104,7 +104,7 @@ var (
 		},
 		[]string{
 			"topology",             // either "Auto" or "Disabled"
-			"traffic_distribution", // "PreferClose" or <empty>
+			"traffic_distribution", // a trafficDistribution value or <empty>
 		},
 	)
 

staging/src/k8s.io/endpointslice/reconciler.go

@@ -51,9 +51,13 @@ type Reconciler struct {
 	// topologyCache tracks the distribution of Nodes and endpoints across zones
 	// to enable TopologyAwareHints.
 	topologyCache *topologycache.TopologyCache
-	// trafficDistributionEnabled determines if endpointDistribution field is to
+	// trafficDistributionEnabled determines if trafficDistribution field is to
 	// be considered when reconciling EndpointSlice hints.
 	trafficDistributionEnabled bool
+	// preferSameTrafficDistribution determines if the new (PreferSameZone /
+	// PreferSameNode) trafficDistribution values should be considered when
+	// reconciling EndpointSlice hints.
+	preferSameTrafficDistribution bool
 	// eventRecorder allows Reconciler to record and publish events.
 	eventRecorder  record.EventRecorder
 	controllerName string
@@ -63,12 +67,32 @@ type ReconcilerOption func(*Reconciler)
 
 // WithTrafficDistributionEnabled controls whether the Reconciler considers the
 // `trafficDistribution` field while reconciling EndpointSlices.
-func WithTrafficDistributionEnabled(enabled bool) ReconcilerOption {
+func WithTrafficDistributionEnabled(enabled, preferSame bool) ReconcilerOption {
 	return func(r *Reconciler) {
 		r.trafficDistributionEnabled = enabled
+		r.preferSameTrafficDistribution = preferSame
 	}
 }
 
+// validTrafficDistribution determines whether TrafficDistribution is set and valid for
+// this cluster.
+func (r *Reconciler) validTrafficDistribution(trafficDistribution *string) bool {
+	if trafficDistribution == nil || !r.trafficDistributionEnabled {
+		return false
+	}
+	if *trafficDistribution == corev1.ServiceTrafficDistributionPreferClose {
+		return true
+	}
+	if !r.preferSameTrafficDistribution {
+		return false
+	}
+	if *trafficDistribution == corev1.ServiceTrafficDistributionPreferSameZone ||
+		*trafficDistribution == corev1.ServiceTrafficDistributionPreferSameNode {
+		return true
+	}
+	return false
+}
+
 // endpointMeta includes the attributes we group slices on, this type helps with
 // that logic in Reconciler
 type endpointMeta struct {
@@ -275,7 +299,7 @@ func (r *Reconciler) reconcileByAddressType(logger klog.Logger, service *corev1.
 		Unchanged:   unchangedSlices(existingSlices, slicesToUpdate, slicesToDelete),
 	}
 
-	canUseTrafficDistribution := r.trafficDistributionEnabled && !hintsEnabled(service.Annotations)
+	canUseTrafficDistribution := r.validTrafficDistribution(service.Spec.TrafficDistribution) && !hintsEnabled(service.Annotations)
 
 	// Check if we need to add/remove hints based on the topology annotation.
 	//
@@ -455,10 +479,8 @@ func (r *Reconciler) finalize(
 		topologyLabel = "Auto"
 	}
 	var trafficDistribution string
-	if r.trafficDistributionEnabled && !hintsEnabled(service.Annotations) {
-		if service.Spec.TrafficDistribution != nil && *service.Spec.TrafficDistribution == corev1.ServiceTrafficDistributionPreferClose {
-			trafficDistribution = *service.Spec.TrafficDistribution
-		}
+	if r.validTrafficDistribution(service.Spec.TrafficDistribution) && !hintsEnabled(service.Annotations) {
+		trafficDistribution = *service.Spec.TrafficDistribution
 	}
 
 	numSlicesChanged := len(slicesToCreate) + len(slicesToUpdate) + len(slicesToDelete)

staging/src/k8s.io/endpointslice/reconciler_test.go

@@ -2017,11 +2017,13 @@ func TestReconcile_TrafficDistribution(t *testing.T) {
 		desc string
 
 		trafficDistributionFeatureGateEnabled bool
+		preferSameFeatureGateEnabled          bool
 		trafficDistribution                   *string
 		topologyAnnotation                    string
 
-		// Defines how many hints belong to a particular zone.
+		// Defines how many hints belong to a particular zone/node
 		wantHintsDistributionByZone map[string]int
+		wantHintsDistributionByNode map[string]int
 		// Number of endpoints where the zone hints are different from the zone of
 		// the endpoint itself.
 		wantEndpointsWithCrossZoneHints int
@@ -2123,6 +2125,62 @@ func TestReconcile_TrafficDistribution(t *testing.T) {
 				slicesChangedPerSyncTrafficDist: 0, // 0 means trafficDistribution was not used.
 			},
 		},
+		{
+			name:                                  "trafficDistribution=PreferSameNode, PSTD enabled",
+			desc:                                  "When trafficDistribution is PreferSameNode and PreferSameTrafficDistribution is enabled, both zone and node hints should be filled out",
+			trafficDistributionFeatureGateEnabled: true,
+			preferSameFeatureGateEnabled:          true,
+			trafficDistribution:                   ptr.To(corev1.ServiceTrafficDistributionPreferSameNode),
+			topologyAnnotation:                    "Disabled",
+			wantHintsDistributionByZone: map[string]int{
+				"zone-a": 1, // {pod-0}
+				"zone-b": 3, // {pod-1, pod-2, pod-3}
+				"zone-c": 2, // {pod-4, pod-5}
+			},
+			wantHintsDistributionByNode: map[string]int{
+				"node-0": 1, // {pod-0}
+				"node-1": 3, // {pod-1, pod-2, pod-3}
+				"node-2": 2, // {pod-4, pod-5}
+			},
+			wantMetrics: expectedMetrics{
+				desiredSlices:                   1,
+				actualSlices:                    1,
+				desiredEndpoints:                6,
+				addedPerSync:                    6,
+				removedPerSync:                  0,
+				numCreated:                      1,
+				numUpdated:                      0,
+				numDeleted:                      0,
+				slicesChangedPerSync:            0, // 0 means either topologyAnnotation or trafficDistribution was used.
+				slicesChangedPerSyncTopology:    0, // 0 means topologyAnnotation was not used.
+				slicesChangedPerSyncTrafficDist: 1, // 1 EPS configured using trafficDistribution.
+				servicesCountByTrafficDistribution: map[string]int{
+					"PreferSameNode": 1,
+				},
+			},
+		},
+		{
+			name:                                  "trafficDistribution=PreferSameZone, PSTD disabled",
+			desc:                                  "When trafficDistribution is PreferSameZone and PreferSameTrafficDistribution is disabled, no hints should be set",
+			trafficDistributionFeatureGateEnabled: true,
+			preferSameFeatureGateEnabled:          false,
+			trafficDistribution:                   ptr.To(corev1.ServiceTrafficDistributionPreferSameZone),
+			topologyAnnotation:                    "Disabled",
+			wantHintsDistributionByZone:           map[string]int{"": 6}, // Equivalent to no hints.
+			wantMetrics: expectedMetrics{
+				desiredSlices:                   1,
+				actualSlices:                    1,
+				desiredEndpoints:                6,
+				addedPerSync:                    6,
+				removedPerSync:                  0,
+				numCreated:                      1,
+				numUpdated:                      0,
+				numDeleted:                      0,
+				slicesChangedPerSync:            1, // 1 means both topologyAnnotation and trafficDistribution were not used.
+				slicesChangedPerSyncTopology:    0, // 0 means topologyAnnotation was not used.
+				slicesChangedPerSyncTrafficDist: 0, // 0 means trafficDistribution was not used.
+			},
+		},
 	}
 
 	// Make assertions.
@@ -2135,6 +2193,7 @@ func TestReconcile_TrafficDistribution(t *testing.T) {
 
 			r := newReconciler(client, nodes, defaultMaxEndpointsPerSlice)
 			r.trafficDistributionEnabled = tc.trafficDistributionFeatureGateEnabled
+			r.preferSameTrafficDistribution = tc.preferSameFeatureGateEnabled
 			r.topologyCache = topologycache.NewTopologyCache()
 			r.topologyCache.SetNodes(logger, nodes)
 
@@ -2397,8 +2456,13 @@ func expectMetrics(t *testing.T, em expectedMetrics) {
 		t.Errorf("Expected slicesChangedPerSyncTopology to be %d, got %v", em.slicesChangedPerSyncTopology, actualSlicesChangedPerSyncTopology)
 	}
 
-	actualSlicesChangedPerSyncTrafficDist, err := testutil.GetHistogramMetricValue(metrics.EndpointSlicesChangedPerSync.WithLabelValues("Disabled", "PreferClose"))
-	handleErr(t, err, "slicesChangedPerSyncTrafficDist")
+	actualSlicesChangedPreferClose, err := testutil.GetHistogramMetricValue(metrics.EndpointSlicesChangedPerSync.WithLabelValues("Disabled", "PreferClose"))
+	handleErr(t, err, "slicesChangedPreferClose")
+	actualSlicesChangedPreferSameZone, err := testutil.GetHistogramMetricValue(metrics.EndpointSlicesChangedPerSync.WithLabelValues("Disabled", "PreferSameZone"))
+	handleErr(t, err, "slicesChangedPreferSameZone")
+	actualSlicesChangedPreferSameNode, err := testutil.GetHistogramMetricValue(metrics.EndpointSlicesChangedPerSync.WithLabelValues("Disabled", "PreferSameNode"))
+	handleErr(t, err, "slicesChangedPreferSameNode")
+	actualSlicesChangedPerSyncTrafficDist := actualSlicesChangedPreferClose + actualSlicesChangedPreferSameZone + actualSlicesChangedPreferSameNode
 	if actualSlicesChangedPerSyncTrafficDist != float64(em.slicesChangedPerSyncTrafficDist) {
 		t.Errorf("Expected slicesChangedPerSyncTrafficDist to be %d, got %v", em.slicesChangedPerSyncTrafficDist, actualSlicesChangedPerSyncTopology)
 	}

staging/src/k8s.io/endpointslice/trafficdist/trafficdist.go

@@ -20,6 +20,14 @@ package trafficdist
 import (
 	corev1 "k8s.io/api/core/v1"
 	discoveryv1 "k8s.io/api/discovery/v1"
+	"k8s.io/apimachinery/pkg/util/sets"
+)
+
+// TrafficDistribution values supported by preferCloseHeuristic
+var closeTrafficDistribution = sets.New(
+	corev1.ServiceTrafficDistributionPreferClose,
+	corev1.ServiceTrafficDistributionPreferSameZone,
+	corev1.ServiceTrafficDistributionPreferSameNode,
 )
 
 // ReconcileHints will reconcile hints for the given EndpointSlices.
@@ -28,12 +36,12 @@ import (
 func ReconcileHints(trafficDistribution *string, slicesToCreate, slicesToUpdate, slicesUnchanged []*discoveryv1.EndpointSlice) ([]*discoveryv1.EndpointSlice, []*discoveryv1.EndpointSlice, []*discoveryv1.EndpointSlice) {
 	var h heuristic = &defaultHeuristic{}
 
-	if trafficDistribution != nil && *trafficDistribution == corev1.ServiceTrafficDistributionPreferClose {
-		h = &preferCloseHeuristic{}
+	if trafficDistribution != nil && closeTrafficDistribution.Has(*trafficDistribution) {
+		h = &preferCloseHeuristic{*trafficDistribution == corev1.ServiceTrafficDistributionPreferSameNode}
 	}
 
 	// Identify the Unchanged slices that need an update because of missing or
-	// incorrect zone hint.
+	// incorrect hints.
 	//
 	// Uses filtering in place to remove any endpoints that are no longer
 	// unchanged and need to be moved to slicesToUpdate
@@ -101,13 +109,14 @@ func (defaultHeuristic) update(slice *discoveryv1.EndpointSlice) {
 	}
 }
 
-// preferCloseHeuristic adds
+// preferCloseHeuristic implements PreferSameZone/PreferClose and PreferSameNode
 type preferCloseHeuristic struct {
+	generateNodeHints bool
 }
 
 // needsUpdate returns true if any ready endpoint in the slice has a
 // missing or incorrect hint.
-func (preferCloseHeuristic) needsUpdate(slice *discoveryv1.EndpointSlice) bool {
+func (h preferCloseHeuristic) needsUpdate(slice *discoveryv1.EndpointSlice) bool {
 	if slice == nil {
 		return false
 	}
@@ -129,25 +138,44 @@ func (preferCloseHeuristic) needsUpdate(slice *discoveryv1.EndpointSlice) bool {
 				return true
 			}
 		}
+
+		if endpoint.NodeName != nil && h.generateNodeHints {
+			// We want a node hint.
+			if endpoint.Hints == nil || len(endpoint.Hints.ForNodes) != 1 || endpoint.Hints.ForNodes[0].Name != *endpoint.NodeName {
+				// ...but it's either missing or incorrect
+				return true
+			}
+		} else {
+			// We don't want a node hint.
+			if endpoint.Hints != nil && len(endpoint.Hints.ForNodes) > 0 {
+				// ... but we have a stale hint.
+				return true
+			}
+		}
 	}
 	return false
 }
 
 // update adds a same zone topology hint for all ready endpoints
-func (preferCloseHeuristic) update(slice *discoveryv1.EndpointSlice) {
+func (h preferCloseHeuristic) update(slice *discoveryv1.EndpointSlice) {
 	for i, endpoint := range slice.Endpoints {
 		if !endpointReady(endpoint) {
 			continue
 		}
 
 		var forZones []discoveryv1.ForZone
+		var forNodes []discoveryv1.ForNode
 		if endpoint.Zone != nil {
 			forZones = []discoveryv1.ForZone{{Name: *endpoint.Zone}}
 		}
+		if endpoint.NodeName != nil && h.generateNodeHints {
+			forNodes = []discoveryv1.ForNode{{Name: *endpoint.NodeName}}
+		}
 
-		if forZones != nil {
+		if forZones != nil || forNodes != nil {
 			slice.Endpoints[i].Hints = &discoveryv1.EndpointHints{
 				ForZones: forZones,
+				ForNodes: forNodes,
 			}
 		} else {
 			slice.Endpoints[i].Hints = nil

staging/src/k8s.io/endpointslice/trafficdist/trafficdist_test.go

@@ -188,6 +188,328 @@ func TestReconcileHints(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "should set zone hints with PreferSameZone",
+
+			trafficDistribution: ptr.To(corev1.ServiceTrafficDistributionPreferSameZone),
+			slicesToCreate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.1"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-1"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.2"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-2"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.3"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-3"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.4"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-4"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+			},
+			slicesToUpdate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.5"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-5"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.6"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-6"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.7"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-7"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.8"},
+							Zone:       ptr.To("zone-c"),
+							NodeName:   ptr.To("node-8"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+			},
+			wantSlicesToCreate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.1"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-1"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints:      &discoveryv1.EndpointHints{ForZones: []discoveryv1.ForZone{{Name: "zone-a"}}},
+						},
+						{
+							Addresses:  []string{"10.0.0.2"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-2"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints:      &discoveryv1.EndpointHints{ForZones: []discoveryv1.ForZone{{Name: "zone-b"}}},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.3"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-3"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints:      &discoveryv1.EndpointHints{ForZones: []discoveryv1.ForZone{{Name: "zone-a"}}},
+						},
+						{
+							Addresses:  []string{"10.0.0.4"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-4"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints:      &discoveryv1.EndpointHints{ForZones: []discoveryv1.ForZone{{Name: "zone-b"}}},
+						},
+					},
+				},
+			},
+			wantSlicesToUpdate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.5"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-5"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints:      &discoveryv1.EndpointHints{ForZones: []discoveryv1.ForZone{{Name: "zone-a"}}},
+						},
+						{
+							Addresses:  []string{"10.0.0.6"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-6"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints:      &discoveryv1.EndpointHints{ForZones: []discoveryv1.ForZone{{Name: "zone-a"}}},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.7"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-7"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints:      &discoveryv1.EndpointHints{ForZones: []discoveryv1.ForZone{{Name: "zone-b"}}},
+						},
+						{
+							Addresses:  []string{"10.0.0.8"},
+							Zone:       ptr.To("zone-c"),
+							NodeName:   ptr.To("node-8"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints:      &discoveryv1.EndpointHints{ForZones: []discoveryv1.ForZone{{Name: "zone-c"}}},
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "should set zone and node hints with PreferSameNode",
+
+			trafficDistribution: ptr.To(corev1.ServiceTrafficDistributionPreferSameNode),
+			slicesToCreate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.1"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-1"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.2"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-2"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.3"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-3"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.4"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-4"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+			},
+			slicesToUpdate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.5"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-5"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.6"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-6"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.7"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-7"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.8"},
+							Zone:       ptr.To("zone-c"),
+							NodeName:   ptr.To("node-8"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+			},
+			wantSlicesToCreate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.1"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-1"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForZones: []discoveryv1.ForZone{{Name: "zone-a"}},
+								ForNodes: []discoveryv1.ForNode{{Name: "node-1"}},
+							},
+						},
+						{
+							Addresses:  []string{"10.0.0.2"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-2"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForZones: []discoveryv1.ForZone{{Name: "zone-b"}},
+								ForNodes: []discoveryv1.ForNode{{Name: "node-2"}},
+							},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.3"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-3"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForZones: []discoveryv1.ForZone{{Name: "zone-a"}},
+								ForNodes: []discoveryv1.ForNode{{Name: "node-3"}},
+							},
+						},
+						{
+							Addresses:  []string{"10.0.0.4"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-4"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForZones: []discoveryv1.ForZone{{Name: "zone-b"}},
+								ForNodes: []discoveryv1.ForNode{{Name: "node-4"}},
+							},
+						},
+					},
+				},
+			},
+			wantSlicesToUpdate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.5"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-5"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForZones: []discoveryv1.ForZone{{Name: "zone-a"}},
+								ForNodes: []discoveryv1.ForNode{{Name: "node-5"}},
+							},
+						},
+						{
+							Addresses:  []string{"10.0.0.6"},
+							Zone:       ptr.To("zone-a"),
+							NodeName:   ptr.To("node-6"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForZones: []discoveryv1.ForZone{{Name: "zone-a"}},
+								ForNodes: []discoveryv1.ForNode{{Name: "node-6"}},
+							},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.7"},
+							Zone:       ptr.To("zone-b"),
+							NodeName:   ptr.To("node-7"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForZones: []discoveryv1.ForZone{{Name: "zone-b"}},
+								ForNodes: []discoveryv1.ForNode{{Name: "node-7"}},
+							},
+						},
+						{
+							Addresses:  []string{"10.0.0.8"},
+							Zone:       ptr.To("zone-c"),
+							NodeName:   ptr.To("node-8"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForZones: []discoveryv1.ForZone{{Name: "zone-c"}},
+								ForNodes: []discoveryv1.ForNode{{Name: "node-8"}},
+							},
+						},
+					},
+				},
+			},
+		},
 		{
 			name: "should correct incorrect hints with PreferClose",
 
@@ -265,7 +587,7 @@ func TestReconcileHints(t *testing.T) {
 			},
 		},
 		{
-			name: "should not create zone hints if there are no zones",
+			name: "should not create hints with PreferClose if there are no zones",
 
 			trafficDistribution: ptr.To(corev1.ServiceTrafficDistributionPreferClose),
 			slicesToCreate: []*discoveryv1.EndpointSlice{
@@ -389,6 +711,155 @@ func TestReconcileHints(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "should create only node hints with PreferSameNode if there are no zones",
+
+			trafficDistribution: ptr.To(corev1.ServiceTrafficDistributionPreferSameNode),
+			slicesToCreate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.1"},
+							NodeName:   ptr.To("node-1"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.2"},
+							NodeName:   ptr.To("node-2"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.3"},
+							NodeName:   ptr.To("node-3"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.4"},
+							NodeName:   ptr.To("node-4"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+			},
+			slicesToUpdate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.5"},
+							NodeName:   ptr.To("node-5"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.6"},
+							NodeName:   ptr.To("node-6"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.7"},
+							NodeName:   ptr.To("node-7"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+						{
+							Addresses:  []string{"10.0.0.8"},
+							NodeName:   ptr.To("node-8"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+						},
+					},
+				},
+			},
+			wantSlicesToCreate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.1"},
+							NodeName:   ptr.To("node-1"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForNodes: []discoveryv1.ForNode{{Name: "node-1"}},
+							},
+						},
+						{
+							Addresses:  []string{"10.0.0.2"},
+							NodeName:   ptr.To("node-2"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForNodes: []discoveryv1.ForNode{{Name: "node-2"}},
+							},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.3"},
+							NodeName:   ptr.To("node-3"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForNodes: []discoveryv1.ForNode{{Name: "node-3"}},
+							},
+						},
+						{
+							Addresses:  []string{"10.0.0.4"},
+							NodeName:   ptr.To("node-4"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForNodes: []discoveryv1.ForNode{{Name: "node-4"}},
+							},
+						},
+					},
+				},
+			},
+			wantSlicesToUpdate: []*discoveryv1.EndpointSlice{
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.5"},
+							NodeName:   ptr.To("node-5"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForNodes: []discoveryv1.ForNode{{Name: "node-5"}},
+							},
+						},
+						{
+							Addresses:  []string{"10.0.0.6"},
+							NodeName:   ptr.To("node-6"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForNodes: []discoveryv1.ForNode{{Name: "node-6"}},
+							},
+						},
+					},
+				},
+				{
+					Endpoints: []discoveryv1.Endpoint{
+						{
+							Addresses:  []string{"10.0.0.7"},
+							NodeName:   ptr.To("node-7"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForNodes: []discoveryv1.ForNode{{Name: "node-7"}},
+							},
+						},
+						{
+							Addresses:  []string{"10.0.0.8"},
+							NodeName:   ptr.To("node-8"),
+							Conditions: discoveryv1.EndpointConditions{Ready: ptr.To(true)},
+							Hints: &discoveryv1.EndpointHints{
+								ForNodes: []discoveryv1.ForNode{{Name: "node-8"}},
+							},
+						},
+					},
+				},
+			},
+		},
 		{
 			name: "unready endpoints should not trigger updates",