First phase - Implement ZoneAware Lb Config

Signed-off-by: Jukie <[email protected]>

Author: jukie

internal/gatewayapi/route.go

@@ -1418,7 +1418,7 @@ func (t *Translator) processDestination(name string, backendRefContext BackendRe
 		ds = t.processServiceDestinationSetting(name, backendRef.BackendObjectReference, backendNamespace, protocol, resources, envoyProxy)
 		svc := resources.GetService(backendNamespace, string(backendRef.Name))
 		ds.IPFamily = getServiceIPFamily(svc)
-		ds.ZoneAwareRouting = processZoneAwareRouting(svc)
+		ds.PreferLocal = processPreferLocalZone(svc)
 
 	case egv1a1.KindBackend:
 		ds = t.processBackendDestinationSetting(name, backendRef.BackendObjectReference, backendNamespace, protocol, resources)
@@ -1591,12 +1591,12 @@ func (t *Translator) processServiceDestinationSetting(
 	}
 
 	return &ir.DestinationSetting{
-		Name:             name,
-		Protocol:         protocol,
-		Endpoints:        endpoints,
-		AddressType:      addrType,
-		ZoneAwareRouting: processZoneAwareRouting(service),
-		Metadata:         buildResourceMetadata(service, ptr.To(gwapiv1.SectionName(strconv.Itoa(int(*backendRef.Port))))),
+		Name:        name,
+		Protocol:    protocol,
+		Endpoints:   endpoints,
+		AddressType: addrType,
+		PreferLocal: processPreferLocalZone(service),
+		Metadata:    buildResourceMetadata(service, ptr.To(gwapiv1.SectionName(strconv.Itoa(int(*backendRef.Port))))),
 	}
 }
 
@@ -1616,14 +1616,17 @@ func getBackendFilters(routeType gwapiv1.Kind, backendRefContext BackendRefConte
 	return nil
 }
 
-func processZoneAwareRouting(svc *corev1.Service) *ir.ZoneAwareRouting {
+func processPreferLocalZone(svc *corev1.Service) *ir.PreferLocalZone {
 	if svc == nil {
 		return nil
 	}
 
 	if trafficDist := svc.Spec.TrafficDistribution; trafficDist != nil {
-		return &ir.ZoneAwareRouting{
-			MinSize: 1,
+		return &ir.PreferLocalZone{
+			MinEndpointsThreshold: ptr.To[uint64](1),
+			Force: &ir.ForceLocalZone{
+				MinEndpointsInZoneThreshold: ptr.To[uint32](1),
+			},
 		}
 	}
 
@@ -1632,8 +1635,11 @@ func processZoneAwareRouting(svc *corev1.Service) *ir.ZoneAwareRouting {
 	// https://kubernetes.io/docs/concepts/services-networking/topology-aware-routing/#enabling-topology-aware-routing
 	// https://github.com/kubernetes/kubernetes/blob/9d9e1afdf78bce0a517cc22557457f942040ca19/staging/src/k8s.io/endpointslice/utils.go#L355-L368
 	if val, ok := svc.Annotations[corev1.AnnotationTopologyMode]; ok && val == "Auto" || val == "auto" {
-		return &ir.ZoneAwareRouting{
-			MinSize: 3,
+		return &ir.PreferLocalZone{
+			MinEndpointsThreshold: ptr.To[uint64](3),
+			Force: &ir.ForceLocalZone{
+				MinEndpointsInZoneThreshold: ptr.To[uint32](3),
+			},
 		}
 	}
 

internal/gatewayapi/testdata/httproute-with-enable-zone-discovery.out.yaml

@@ -157,10 +157,12 @@ xdsIR:
               namespace: default
               sectionName: "8080"
             name: httproute/default/httproute-1/rule/1/backend/0
+            preferLocal:
+              force:
+                minEndpointsInZoneThreshold: 1
+              minEndpointsThreshold: 1
             protocol: HTTP
             weight: 1
-            zoneAwareRouting:
-              minSize: 1
         headerMatches:
         - distinct: false
           exact: bar
@@ -195,10 +197,12 @@ xdsIR:
               namespace: default
               sectionName: "8080"
             name: httproute/default/httproute-1/rule/0/backend/0
+            preferLocal:
+              force:
+                minEndpointsInZoneThreshold: 1
+              minEndpointsThreshold: 1
             protocol: HTTP
             weight: 1
-            zoneAwareRouting:
-              minSize: 1
         hostname: '*'
         isHTTP2: false
         metadata:

internal/ir/xds.go

@@ -813,6 +813,16 @@ func (h *HTTPRoute) GetRetry() *Retry {
 	return nil
 }
 
+func (h *HTTPRoute) NeedsClusterPerSetting() bool {
+	if h.Traffic != nil &&
+		h.Traffic.LoadBalancer != nil &&
+		h.Traffic.LoadBalancer.ZoneAware != nil &&
+		h.Traffic.LoadBalancer.ZoneAware.PreferLocal != nil {
+		return true
+	}
+	return h.Destination.NeedsClusterPerSetting()
+}
+
 // DNS contains configuration options for DNS resolution.
 // +k8s:deepcopy-gen=true
 type DNS struct {
@@ -1552,7 +1562,7 @@ func (r *RouteDestination) Validate() error {
 func (r *RouteDestination) NeedsClusterPerSetting() bool {
 	return r.HasMixedEndpoints() ||
 		r.HasFiltersInSettings() ||
-		(len(r.Settings) > 1 && r.HasZoneAwareRouting())
+		(len(r.Settings) > 1 && r.HasPreferLocalZone())
 }
 
 // HasMixedEndpoints returns true if the RouteDestination has endpoints of multiple types
@@ -1577,10 +1587,10 @@ func (r *RouteDestination) HasFiltersInSettings() bool {
 	return false
 }
 
-// HasZoneAwareRouting returns true if any setting in the destination has ZoneAwareRoutingEnabled set
-func (r *RouteDestination) HasZoneAwareRouting() bool {
+// HasPreferLocalZone returns true if any setting in the destination has PreferLocalZone set
+func (r *RouteDestination) HasPreferLocalZone() bool {
 	for _, setting := range r.Settings {
-		if setting.ZoneAwareRouting != nil {
+		if setting.PreferLocal != nil {
 			return true
 		}
 	}
@@ -1643,11 +1653,9 @@ type DestinationSetting struct {
 	IPFamily *egv1a1.IPFamily    `json:"ipFamily,omitempty" yaml:"ipFamily,omitempty"`
 	TLS      *TLSUpstreamConfig  `json:"tls,omitempty" yaml:"tls,omitempty"`
 	Filters  *DestinationFilters `json:"filters,omitempty" yaml:"filters,omitempty"`
-	// ZoneAwareRouting specifies whether to enable Zone Aware Routing for this destination's endpoints.
+	// PreferLocal specifies whether to enable Zone Aware Routing for this destination's endpoints.
 	// This is derived from the backend service and depends on having Kubernetes Topology Aware Routing or Traffic Distribution enabled.
-	//
-	// +optional
-	ZoneAwareRouting *ZoneAwareRouting `json:"zoneAwareRouting,omitempty" yaml:"zoneAwareRouting,omitempty"`
+	PreferLocal *PreferLocalZone `json:"preferLocal,omitempty" yaml:"preferLocal,omitempty"`
 	// Metadata is used to enrich envoy route metadata with user and provider-specific information
 	// The primary metadata for DestinationSettings comes from the Backend resource reference in BackendRef
 	Metadata *ResourceMetadata `json:"metadata,omitempty" yaml:"metadata,omitempty"`
@@ -2490,6 +2498,8 @@ type LoadBalancer struct {
 	Random *Random `json:"random,omitempty" yaml:"random,omitempty"`
 	// ConsistentHash load balancer policy
 	ConsistentHash *ConsistentHash `json:"consistentHash,omitempty" yaml:"consistentHash,omitempty"`
+	// ZoneAware defines the configuration related to the distribution of requests between locality zones.
+	ZoneAware *ZoneAware `json:"zoneAware,omitempty" yaml:"zoneAware,omitempty"`
 }
 
 // Validate the fields within the LoadBalancer structure
@@ -3162,8 +3172,28 @@ type RequestBuffer struct {
 	Limit resource.Quantity `json:"limit" yaml:"limit"`
 }
 
-// ZoneAwareRouting holds the zone aware routing configuration
+// ZoneAware defines the configuration related to the distribution of requests between locality zones.
+// +k8s:deepcopy-gen=true
+type ZoneAware struct {
+	// PreferLocal configures zone-aware routing to prefer sending traffic to the local locality zone.
+	PreferLocal *PreferLocalZone `json:"preferLocal,omitempty" yaml:"preferLocal,omitempty"`
+}
+
+// PreferLocalZone configures zone-aware routing to prefer sending traffic to the local locality zone.
+// +k8s:deepcopy-gen=true
+type PreferLocalZone struct {
+	// ForceLocalZone defines override configuration for forcing all traffic to stay within the local zone instead of the default behavior
+	// which maintains equal distribution among upstream endpoints while sending as much traffic as possible locally.
+	Force *ForceLocalZone `json:"force,omitempty" yaml:"force,omitempty"`
+	// MinEndpointsThreshold is the minimum number of total upstream endpoints across all zones required to enable zone-aware routing.
+	MinEndpointsThreshold *uint64 `json:"minEndpointsThreshold,omitempty" yaml:"minEndpointsThreshold,omitempty"`
+}
+
+// ForceLocalZone defines override configuration for forcing all traffic to stay within the local zone instead of the default behavior
+// which maintains equal distribution among upstream endpoints while sending as much traffic as possible locally.
 // +k8s:deepcopy-gen=true
-type ZoneAwareRouting struct {
-	MinSize int `json:"minSize" yaml:"minSize"`
+type ForceLocalZone struct {
+	// MinEndpointsInZoneThreshold is the minimum number of upstream endpoints in the local zone required to honor the forceLocalZone
+	// override. This is useful for protecting zones with fewer endpoints.
+	MinEndpointsInZoneThreshold *uint32 `json:"minEndpointsInZoneThreshold,omitempty" yaml:"minEndpointsInZoneThreshold,omitempty"`
 }

internal/ir/xds_test.go

@@ -1124,8 +1124,10 @@ func TestRouteDestination_NeedsClusterPerSetting(t *testing.T) {
 								Port: 8080,
 							},
 						},
-						AddressType:      ptr.To(FQDN),
-						ZoneAwareRouting: &ZoneAwareRouting{MinSize: 1},
+						AddressType: ptr.To(FQDN),
+						PreferLocal: &PreferLocalZone{
+							Force: &ForceLocalZone{MinEndpointsInZoneThreshold: ptr.To[uint32](1)},
+						},
 					},
 					{
 						Endpoints: []*DestinationEndpoint{
@@ -1152,8 +1154,10 @@ func TestRouteDestination_NeedsClusterPerSetting(t *testing.T) {
 								Port: 8080,
 							},
 						},
-						AddressType:      ptr.To(FQDN),
-						ZoneAwareRouting: &ZoneAwareRouting{MinSize: 1},
+						AddressType: ptr.To(FQDN),
+						PreferLocal: &PreferLocalZone{
+							Force: &ForceLocalZone{MinEndpointsInZoneThreshold: ptr.To[uint32](1)},
+						},
 					},
 				},
 			},