feat(api): merge backends

api/v1alpha1/backendpolicy_types.go

@@ -0,0 +1,25 @@
+package v1alpha1
+
+import (
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	gwapiv1 "sigs.k8s.io/gateway-api/apis/v1"
+)
+
+// BackendPolicy allows the user to configure the behavior of the connection
+// between the Envoy Proxy and the backend service.
+type BackendPolicy struct {
+	metav1.TypeMeta   `json:",inline"`
+	metav1.ObjectMeta `json:"metadata,omitempty"`
+
+	// spec defines the desired state of BackendPolicySpec.
+	Spec BackendPolicySpec `json:"spec"`
+
+	// status defines the current status of BackendPolicySpec.
+	Status gwapiv1.PolicyStatus `json:"status,omitempty"`
+}
+
+// BackendPolicySpec defines the desired state of BackendPolicy.
+type BackendPolicySpec struct {
+	PolicyTargetReferences `json:",inline"`
+	ClusterSettings        `json:",inline"`
+}

api/v1alpha1/backendtrafficpolicy_types.go

@@ -16,8 +16,8 @@ const (
 	KindBackendTrafficPolicy = "BackendTrafficPolicy"
 )
 
-// BackendTrafficPolicy allows the user to configure the behavior of the connection
-// between the Envoy Proxy listener and the backend service.
+// BackendTrafficPolicy allows the user to override the behavior of the connection
+// between the Envoy Proxy listener and the backend service for a specific xRoute.
 //
 // +kubebuilder:object:root=true
 // +kubebuilder:resource:categories=envoy-gateway,shortName=btp

api/v1alpha1/envoyproxy_types.go

@@ -90,6 +90,15 @@ type EnvoyProxySpec struct {
 	// +optional
 	MergeGateways *bool `json:"mergeGateways,omitempty"`
 
+	// MergeBackends defines if backends with the same identity across different xRoutes
+	// should be merged to reduce the number of clusters in the Envoy configuration.
+	// When set to true, backends that share the same identity (i.e., same namespace and name)
+	// will be consolidated into a single cluster, even if they are referenced by different HTTPRoutes.
+	// This can help optimize resource usage and improve performance by minimizing redundant clusters.
+	//
+	// +optional
+	MergeBackends *bool `json:"mergeBackends,omitempty"`
+
 	// Shutdown defines configuration for graceful envoy shutdown process.
 	//
 	// +optional

charts/gateway-crds-helm/templates/generated/gateway.envoyproxy.io_backendtrafficpolicies.yaml

@@ -27,8 +27,8 @@ spec:
     schema:
       openAPIV3Schema:
         description: |-
-          BackendTrafficPolicy allows the user to configure the behavior of the connection
-          between the Envoy Proxy listener and the backend service.
+          BackendTrafficPolicy allows the user to override the behavior of the connection
+          between the Envoy Proxy listener and the backend service for a specific xRoute.
         properties:
           apiVersion:
             description: |-

charts/gateway-crds-helm/templates/generated/gateway.envoyproxy.io_envoyproxies.yaml

@@ -468,6 +468,14 @@ spec:
                 - Strict
                 - Disabled
                 type: string
+              mergeBackends:
+                description: |-
+                  MergeBackends defines if backends with the same identity across different xRoutes
+                  should be merged to reduce the number of clusters in the Envoy configuration.
+                  When set to true, backends that share the same identity (i.e., same namespace and name)
+                  will be consolidated into a single cluster, even if they are referenced by different HTTPRoutes.
+                  This can help optimize resource usage and improve performance by minimizing redundant clusters.
+                type: boolean
               mergeGateways:
                 description: |-
                   MergeGateways defines if Gateway resources should be merged onto the same Envoy Proxy Infrastructure.

charts/gateway-helm/crds/generated/gateway.envoyproxy.io_backendtrafficpolicies.yaml

@@ -26,8 +26,8 @@ spec:
     schema:
       openAPIV3Schema:
         description: |-
-          BackendTrafficPolicy allows the user to configure the behavior of the connection
-          between the Envoy Proxy listener and the backend service.
+          BackendTrafficPolicy allows the user to override the behavior of the connection
+          between the Envoy Proxy listener and the backend service for a specific xRoute.
         properties:
           apiVersion:
             description: |-

charts/gateway-helm/crds/generated/gateway.envoyproxy.io_envoyproxies.yaml

@@ -467,6 +467,14 @@ spec:
                 - Strict
                 - Disabled
                 type: string
+              mergeBackends:
+                description: |-
+                  MergeBackends defines if backends with the same identity across different xRoutes
+                  should be merged to reduce the number of clusters in the Envoy configuration.
+                  When set to true, backends that share the same identity (i.e., same namespace and name)
+                  will be consolidated into a single cluster, even if they are referenced by different HTTPRoutes.
+                  This can help optimize resource usage and improve performance by minimizing redundant clusters.
+                type: boolean
               mergeGateways:
                 description: |-
                   MergeGateways defines if Gateway resources should be merged onto the same Envoy Proxy Infrastructure.

internal/gatewayapi/helpers.go

@@ -475,6 +475,10 @@ func IsMergeGatewaysEnabled(resources *resource.Resources) bool {
 	return resources.EnvoyProxyForGatewayClass != nil && resources.EnvoyProxyForGatewayClass.Spec.MergeGateways != nil && *resources.EnvoyProxyForGatewayClass.Spec.MergeGateways
 }
 
+func IsMergeBackendsEnabled(resources *resource.Resources) bool {
+	return resources.EnvoyProxyForGatewayClass != nil && resources.EnvoyProxyForGatewayClass.Spec.MergeBackends != nil && *resources.EnvoyProxyForGatewayClass.Spec.MergeBackends
+}
+
 func protocolSliceToStringSlice(protocols []gwapiv1.ProtocolType) []string {
 	protocolStrings := make([]string, 0, len(protocols))
 	for _, protocol := range protocols {

internal/gatewayapi/runner/runner.go

@@ -155,6 +155,7 @@ func (r *Runner) subscribeAndTranslate(sub <-chan watchable.Snapshot[string, *re
 					ControllerNamespace:     r.ControllerNamespace,
 					GatewayNamespaceMode:    r.EnvoyGateway.GatewayNamespaceMode(),
 					MergeGateways:           gatewayapi.IsMergeGatewaysEnabled(resources),
+					MergeBackends:           gatewayapi.IsMergeBackendsEnabled(resources),
 					WasmCache:               r.wasmCache,
 					RunningOnHost:           r.EnvoyGateway.Provider != nil && r.EnvoyGateway.Provider.IsRunningOnHost(),
 					Logger:                  r.Logger,

internal/gatewayapi/translator.go

@@ -88,6 +88,10 @@ type Translator struct {
 	// should be merged under the parent GatewayClass.
 	MergeGateways bool
 
+	// MergeBackends is true when Backend resources with same identity
+	// should be merged under the Gateway.
+	MergeBackends bool
+
 	// GatewayNamespaceMode is true if controller uses gateway namespace mode for infra deployments.
 	GatewayNamespaceMode bool