Set Service address in Gateway Status (#1141)

Problem: NGF would only set the Gateway Status to the IP address of the NGF Pod. However, a Service will generally be the entrypoint, so we need to set that address in the status for application developers.

Solution: Using a CLI argument to identify the Service that is linked to this NGF Pod, we will get the Service and set the Addresses accordingly. LoadBalancer Service will set to the ingress IP and/or Hostname. If no Service exists or there is an error, then the Pod IP is used.

We also shouldn't deploy a Service for conformance tests now, since they could be run in an environment where NodePort doesn't work (like kind). These tests will use the Pod IP.

Author: sjberman

cmd/gateway/commands.go

@@ -69,6 +69,7 @@ func createStaticModeCommand() *cobra.Command {
 	const (
 		gatewayFlag                = "gateway"
 		configFlag                 = "config"
+		serviceFlag                = "service"
 		updateGCStatusFlag         = "update-gatewayclass-status"
 		metricsDisableFlag         = "metrics-disable"
 		metricsSecureFlag          = "metrics-secure-serving"
@@ -86,6 +87,9 @@ func createStaticModeCommand() *cobra.Command {
 		configName     = stringValidatingValue{
 			validator: validateResourceName,
 		}
+		serviceName = stringValidatingValue{
+			validator: validateResourceName,
+		}
 		disableMetrics    bool
 		metricsSecure     bool
 		metricsListenPort = intValidatingValue{
@@ -150,10 +154,13 @@ func createStaticModeCommand() *cobra.Command {
 				Logger:                   logger,
 				AtomicLevel:              atom,
 				GatewayClassName:         gatewayClassName.value,
-				PodIP:                    podIP,
-				Namespace:                namespace,
 				GatewayNsName:            gwNsName,
 				UpdateGatewayClassStatus: updateGCStatus,
+				GatewayPodConfig: config.GatewayPodConfig{
+					PodIP:       podIP,
+					ServiceName: serviceName.value,
+					Namespace:   namespace,
+				},
 				HealthConfig: config.HealthConfig{
 					Enabled: !disableHealth,
 					Port:    healthListenPort.value,
@@ -196,6 +203,13 @@ func createStaticModeCommand() *cobra.Command {
 			` Lives in the same Namespace as the controller.`,
 	)
 
+	cmd.Flags().Var(
+		&serviceName,
+		serviceFlag,
+		`The name of the Service that fronts this NGINX Gateway Fabric Pod.`+
+			` Lives in the same Namespace as the controller.`,
+	)
+
 	cmd.Flags().BoolVar(
 		&updateGCStatus,
 		updateGCStatusFlag,

cmd/gateway/commands_test.go

@@ -117,6 +117,7 @@ func TestStaticModeCmdFlagValidation(t *testing.T) {
 			args: []string{
 				"--gateway=nginx-gateway/nginx",
 				"--config=nginx-gateway-config",
+				"--service=nginx-gateway",
 				"--update-gatewayclass-status=true",
 				"--metrics-port=9114",
 				"--metrics-disable",
@@ -166,6 +167,22 @@ func TestStaticModeCmdFlagValidation(t *testing.T) {
 			wantErr:           true,
 			expectedErrPrefix: `invalid argument "!@#$" for "-c, --config" flag: invalid format`,
 		},
+		{
+			name: "service is set to empty string",
+			args: []string{
+				"--service=",
+			},
+			wantErr:           true,
+			expectedErrPrefix: `invalid argument "" for "--service" flag: must be set`,
+		},
+		{
+			name: "service is set to invalid string",
+			args: []string{
+				"--service=!@#$",
+			},
+			wantErr:           true,
+			expectedErrPrefix: `invalid argument "!@#$" for "--service" flag: invalid format`,
+		},
 		{
 			name: "update-gatewayclass-status is set to empty string",
 			args: []string{

conformance/Makefile

@@ -10,7 +10,6 @@ TAG = latest
 PREFIX = conformance-test-runner
 NGF_MANIFEST=../deploy/manifests/nginx-gateway.yaml
 CRDS=../deploy/manifests/crds/
-SERVICE_MANIFEST=../deploy/manifests/service/nodeport.yaml
 STATIC_MANIFEST=provisioner/static-deployment.yaml
 PROVISIONER_MANIFEST=provisioner/provisioner.yaml
 NGINX_IMAGE=$(shell yq '.spec.template.spec.containers[1].image as $$nginx_ver | $$nginx_ver' $(STATIC_MANIFEST))
@@ -52,7 +51,6 @@ prepare-ngf-dependencies: update-ngf-manifest ## Install NGF dependencies on con
 	kubectl wait --for=condition=available --timeout=60s deployment gateway-api-admission-server -n gateway-system
 	kubectl apply -f $(CRDS)
 	kubectl apply -f $(NGF_MANIFEST)
-	kubectl apply -f $(SERVICE_MANIFEST)
 
 .PHONY: deploy-updated-provisioner
 deploy-updated-provisioner: ## Update provisioner manifest and deploy to the configured kind cluster

conformance/provisioner/static-deployment.yaml

@@ -27,6 +27,7 @@ spec:
         - --gateway-ctlr-name=gateway.nginx.org/nginx-gateway-controller
         - --gatewayclass=nginx
         - --config=nginx-gateway-config
+        - --service=nginx-gateway
         - --metrics-disable
         - --health-port=8081
         - --leader-election-lock-name=nginx-gateway-leader-election

deploy/helm-chart/templates/deployment.yaml

@@ -30,6 +30,7 @@ spec:
         - --gateway-ctlr-name={{ .Values.nginxGateway.gatewayControllerName }}
         - --gatewayclass={{ .Values.nginxGateway.gatewayClassName }}
         - --config={{ include "nginx-gateway.config-name" . }}
+        - --service={{ include "nginx-gateway.fullname" . }}
         {{- if .Values.metrics.enable }}
         - --metrics-port={{ .Values.metrics.port }}
         {{- if .Values.metrics.secure  }}

deploy/manifests/nginx-gateway.yaml

@@ -139,6 +139,7 @@ spec:
         - --gateway-ctlr-name=gateway.nginx.org/nginx-gateway-controller
         - --gatewayclass=nginx
         - --config=nginx-gateway-config
+        - --service=nginx-gateway
         - --metrics-port=9113
         - --health-port=8081
         - --leader-election-lock-name=nginx-gateway-leader-election

docs/cli-help.md

@@ -20,6 +20,7 @@ Flags:
 | `gatewayclass`               | `string` | The name of the GatewayClass resource. Every NGINX Gateway Fabric must have a unique corresponding GatewayClass resource.                                                                                                                                                                                                                                                                                |
 | `gateway`                    | `string` | The namespaced name of the Gateway resource to use. Must be of the form: `NAMESPACE/NAME`. If not specified, the control plane will process all Gateways for the configured GatewayClass. However, among them, it will choose the oldest resource by creation timestamp. If the timestamps are equal, it will choose the resource that appears first in alphabetical order by {namespace}/{name}. |
 | `config`                     | `string` | The name of the NginxGateway resource to be used for this controller's dynamic configuration. Lives in the same Namespace as the controller.                                                                                                                                                                                                                                                      |
+| `service`                    | `string` | The name of the Service that fronts this NGINX Gateway Fabric Pod. Lives in the same Namespace as the controller. |
 | `metrics-disable`            | `bool`   | Disable exposing metrics in the Prometheus format. (default false)                                                                                                                                                                                                                                                                                                                                |
 | `metrics-listen-port`        | `int`    | Sets the port where the Prometheus metrics are exposed. Format: `[1024 - 65535]` (default `9113`)                                                                                                                                                                                                                                                                                                 |
 | `metrics-secure-serving`     | `bool`   | Configures if the metrics endpoint should be secured using https. Please note that this endpoint will be secured with a self-signed certificate. (default false)                                                                                                                                                                                                                                  |

docs/gateway-api-compatibility.md

@@ -68,7 +68,7 @@ Fields:
 > Support Levels:
 >
 > - Core: Supported.
-> - Extended: Not supported.
+> - Extended: Partially supported.
 > - Implementation-specific: Not supported.
 
 NGINX Gateway Fabric supports only a single Gateway resource. The Gateway resource must reference NGINX Gateway
@@ -91,7 +91,7 @@ Fields:
     - `allowedRoutes` - supported.
   - `addresses` - not supported.
 - `status`
-  - `addresses` - Pod IPAddress supported.
+  - `addresses` - partially supported. LoadBalancer and Pod IP.
   - `conditions` - supported (Condition/Status/Reason):
     - `Accepted/True/Accepted`
     - `Accepted/True/ListenersNotValid`

docs/installation.md

@@ -64,6 +64,8 @@ page.
 ## Expose NGINX Gateway Fabric
 
 You can gain access to NGINX Gateway Fabric by creating a `NodePort` Service or a `LoadBalancer` Service.
+This Service must live in the same Namespace as the controller. The name of this Service is provided in
+the `--service` argument to the controller.
 
 > Important
 >
@@ -72,6 +74,9 @@ You can gain access to NGINX Gateway Fabric by creating a `NodePort` Service or
 > configured for those ports. If you'd like to use different ports in your listeners,
 > update the manifests accordingly.
 
+NGINX Gateway Fabric will use this Service to set the Addresses field in the Gateway Status resource. A LoadBalancer
+Service sets the status field to the IP address and/or Hostname. If no Service exists, the Pod IP address is used.
+
 ### Create a NodePort Service
 
 Create a Service with type `NodePort`:

internal/framework/controller/predicate/service.go

@@ -2,7 +2,9 @@ package predicate
 
 import (
 	apiv1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/intstr"
+	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/event"
 	"sigs.k8s.io/controller-runtime/pkg/predicate"
 )
@@ -63,3 +65,54 @@ func (ServicePortsChangedPredicate) Update(e event.UpdateEvent) bool {
 
 	return len(newPortSet) > 0
 }
+
+// GatewayServicePredicate implements predicate functions for this Pod's Service.
+type GatewayServicePredicate struct {
+	predicate.Funcs
+	NSName types.NamespacedName
+}
+
+// Update implements the default UpdateEvent filter for the Gateway Service.
+func (gsp GatewayServicePredicate) Update(e event.UpdateEvent) bool {
+	if e.ObjectOld == nil {
+		return false
+	}
+	if e.ObjectNew == nil {
+		return false
+	}
+
+	oldSvc, ok := e.ObjectOld.(*apiv1.Service)
+	if !ok {
+		return false
+	}
+
+	newSvc, ok := e.ObjectNew.(*apiv1.Service)
+	if !ok {
+		return false
+	}
+
+	if client.ObjectKeyFromObject(newSvc) != gsp.NSName {
+		return false
+	}
+
+	if oldSvc.Spec.Type != newSvc.Spec.Type {
+		return true
+	}
+
+	if newSvc.Spec.Type == apiv1.ServiceTypeLoadBalancer {
+		oldIngress := oldSvc.Status.LoadBalancer.Ingress
+		newIngress := newSvc.Status.LoadBalancer.Ingress
+
+		if len(oldIngress) != len(newIngress) {
+			return true
+		}
+
+		for i, ingress := range oldIngress {
+			if ingress.IP != newIngress[i].IP || ingress.Hostname != newIngress[i].Hostname {
+				return true
+			}
+		}
+	}
+
+	return false
+}