Change kube-proxy behaviour to consider hints when ServiceTrafficDistribution feature gate is enabled

pkg/proxy/topology.go

@@ -137,22 +137,28 @@ func CategorizeEndpoints(endpoints []Endpoint, svcInfo ServicePort, nodeLabels m
 	return
 }
 
-// canUseTopology returns true if topology aware routing is enabled and properly configured
+// canUseTopology returns true if topology aware routing is enabled and properly
-// in this cluster. That is, it checks that:
+// configured in this cluster. That is, it checks that:
-// * The TopologyAwareHints feature is enabled
+//   - The TopologyAwareHints or ServiceTrafficDistribution feature is enabled.
-// * The "service.kubernetes.io/topology-aware-hints" annotation on this Service is set to "Auto"
+//   - If ServiceTrafficDistribution feature gate is not enabled, then the
-// * The node's labels include "topology.kubernetes.io/zone"
+//     hintsAnnotation should represent an enabled value.
-// * All of the endpoints for this Service have a topology hint
+//   - The node's labels include "topology.kubernetes.io/zone".
-// * At least one endpoint for this Service is hinted for this node's zone.
+//   - All of the endpoints for this Service have a topology hint.
+//   - At least one endpoint for this Service is hinted for this node's zone.
 func canUseTopology(endpoints []Endpoint, svcInfo ServicePort, nodeLabels map[string]string) bool {
-	if !utilfeature.DefaultFeatureGate.Enabled(features.TopologyAwareHints) {
+	if !utilfeature.DefaultFeatureGate.Enabled(features.TopologyAwareHints) && !utilfeature.DefaultFeatureGate.Enabled(features.ServiceTrafficDistribution) {
 		return false
 	}
-	// Any non-empty and non-disabled values for the hints annotation are acceptable.
+
+	// Ignore value of hintsAnnotation if the ServiceTrafficDistribution feature
+	// gate is enabled.
+	if !utilfeature.DefaultFeatureGate.Enabled(features.ServiceTrafficDistribution) {
+		// If the hintsAnnotation has a disabled value, we do not consider hints for route programming.
 		hintsAnnotation := svcInfo.HintsAnnotation()
 		if hintsAnnotation == "" || hintsAnnotation == "disabled" || hintsAnnotation == "Disabled" {
 			return false
 		}
+	}
 
 	zone, ok := nodeLabels[v1.LabelTopologyZone]
 	if !ok || zone == "" {

pkg/proxy/topology_test.go

@@ -49,6 +49,7 @@ func TestCategorizeEndpoints(t *testing.T) {
 	testCases := []struct {
 		name                      string
 		hintsEnabled              bool
+		trafficDistFeatureEnabled bool
 		pteEnabled                bool
 		nodeLabels                map[string]string
 		serviceInfo               ServicePort
@@ -130,9 +131,38 @@ func TestCategorizeEndpoints(t *testing.T) {
 		},
 		clusterEndpoints: sets.New[string]("10.1.2.3:80", "10.1.2.4:80", "10.1.2.5:80", "10.1.2.6:80"),
 		localEndpoints:   nil,
+	}, {
+		name:                      "hints, hints annotation empty but trafficDist feature gate enabled, hints are not ignored",
+		hintsEnabled:              true,
+		trafficDistFeatureEnabled: true,
+		nodeLabels:                map[string]string{v1.LabelTopologyZone: "zone-a"},
+		serviceInfo:               &BaseServicePortInfo{},
+		endpoints: []Endpoint{
+			&BaseEndpointInfo{endpoint: "10.1.2.3:80", zoneHints: sets.New[string]("zone-a"), ready: true},
+			&BaseEndpointInfo{endpoint: "10.1.2.4:80", zoneHints: sets.New[string]("zone-b"), ready: true},
+			&BaseEndpointInfo{endpoint: "10.1.2.5:80", zoneHints: sets.New[string]("zone-c"), ready: true},
+			&BaseEndpointInfo{endpoint: "10.1.2.6:80", zoneHints: sets.New[string]("zone-a"), ready: true},
+		},
+		clusterEndpoints: sets.New[string]("10.1.2.3:80", "10.1.2.6:80"),
+		localEndpoints:   nil,
+	}, {
+		name:                      "hints disabled, trafficDist feature gate enabled, hints are not ignored",
+		hintsEnabled:              false,
+		trafficDistFeatureEnabled: true,
+		nodeLabels:                map[string]string{v1.LabelTopologyZone: "zone-a"},
+		serviceInfo:               &BaseServicePortInfo{},
+		endpoints: []Endpoint{
+			&BaseEndpointInfo{endpoint: "10.1.2.3:80", zoneHints: sets.New[string]("zone-a"), ready: true},
+			&BaseEndpointInfo{endpoint: "10.1.2.4:80", zoneHints: sets.New[string]("zone-b"), ready: true},
+			&BaseEndpointInfo{endpoint: "10.1.2.5:80", zoneHints: sets.New[string]("zone-c"), ready: true},
+			&BaseEndpointInfo{endpoint: "10.1.2.6:80", zoneHints: sets.New[string]("zone-a"), ready: true},
+		},
+		clusterEndpoints: sets.New[string]("10.1.2.3:80", "10.1.2.6:80"),
+		localEndpoints:   nil,
 	}, {
 		name:                      "externalTrafficPolicy: Local, topology ignored for Local endpoints",
 		hintsEnabled:              true,
+		trafficDistFeatureEnabled: true,
 		nodeLabels:                map[string]string{v1.LabelTopologyZone: "zone-a"},
 		serviceInfo:               &BaseServicePortInfo{externalPolicyLocal: true, nodePort: 8080, hintsAnnotation: "auto"},
 		endpoints: []Endpoint{
@@ -147,6 +177,7 @@ func TestCategorizeEndpoints(t *testing.T) {
 	}, {
 		name:                      "internalTrafficPolicy: Local, topology ignored for Local endpoints",
 		hintsEnabled:              true,
+		trafficDistFeatureEnabled: true,
 		nodeLabels:                map[string]string{v1.LabelTopologyZone: "zone-a"},
 		serviceInfo:               &BaseServicePortInfo{internalPolicyLocal: true, hintsAnnotation: "auto", externalPolicyLocal: false, nodePort: 8080},
 		endpoints: []Endpoint{
@@ -458,6 +489,7 @@ func TestCategorizeEndpoints(t *testing.T) {
 	for _, tc := range testCases {
 		t.Run(tc.name, func(t *testing.T) {
 			defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.TopologyAwareHints, tc.hintsEnabled)()
+			defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.ServiceTrafficDistribution, tc.trafficDistFeatureEnabled)()
 
 			clusterEndpoints, localEndpoints, allEndpoints, hasAnyEndpoints := CategorizeEndpoints(tc.endpoints, tc.serviceInfo, tc.nodeLabels)