Support Horizontal Scaling

Makefile

@@ -19,7 +19,8 @@ TAG ?= $(VERSION:v%=%)## The tag of the image. For example, 0.3.0
 TARGET ?= local## The target of the build. Possible values: local and container
 KIND_KUBE_CONFIG=$${HOME}/.kube/kind/config## The location of the kind kubeconfig
 OUT_DIR ?= $(shell pwd)/build/out## The folder where the binary will be stored
-ARCH ?= amd64## The architecture of the image and/or binary. For example: amd64 or arm64
+GOARCH ?= amd64## The architecture of the image and/or binary. For example: amd64 or arm64
+GOOS ?= linux## The OS of the image and/or binary. For example: linux or darwin
 override HELM_TEMPLATE_COMMON_ARGS += --set creator=template --set nameOverride=nginx-gateway## The common options for the Helm template command.
 override HELM_TEMPLATE_EXTRA_ARGS_FOR_ALL_MANIFESTS_FILE += --set service.create=false## The options to be passed to the full Helm templating command only.
 override NGINX_DOCKER_BUILD_OPTIONS += --build-arg NJS_DIR=$(NJS_DIR) --build-arg NGINX_CONF_DIR=$(NGINX_CONF_DIR)
@@ -35,11 +36,11 @@ build-images: build-nkg-image build-nginx-image ## Build the NKG and nginx docke
 
 .PHONY: build-nkg-image
 build-nkg-image: check-for-docker build ## Build the NKG docker image
-	docker build --platform linux/$(ARCH) --target $(strip $(TARGET)) -f build/Dockerfile -t $(strip $(PREFIX)):$(strip $(TAG)) .
+	docker build --platform linux/$(GOARCH) --target $(strip $(TARGET)) -f build/Dockerfile -t $(strip $(PREFIX)):$(strip $(TAG)) .
 
 .PHONY: build-nginx-image
 build-nginx-image: check-for-docker ## Build the custom nginx image
-	docker build --platform linux/$(ARCH) $(strip $(NGINX_DOCKER_BUILD_OPTIONS)) -f build/Dockerfile.nginx -t $(strip $(NGINX_PREFIX)):$(strip $(TAG)) .
+	docker build --platform linux/$(GOARCH) $(strip $(NGINX_DOCKER_BUILD_OPTIONS)) -f build/Dockerfile.nginx -t $(strip $(NGINX_PREFIX)):$(strip $(TAG)) .
 
 .PHONY: check-for-docker
 check-for-docker: ## Check if Docker is installed
@@ -49,13 +50,13 @@ check-for-docker: ## Check if Docker is installed
 build: ## Build the binary
 ifeq (${TARGET},local)
 	@go version || (code=$$?; printf "\033[0;31mError\033[0m: unable to build locally\n"; exit $$code)
-	CGO_ENABLED=0 GOOS=linux GOARCH=$(ARCH) go build -trimpath -a -ldflags "$(GO_LINKER_FLAGS)" $(ADDITIONAL_GO_BUILD_FLAGS) -o $(OUT_DIR)/gateway github.com/nginxinc/nginx-kubernetes-gateway/cmd/gateway
+	CGO_ENABLED=0 GOOS=$(GOOS) GOARCH=$(GOARCH) go build -trimpath -a -ldflags "$(GO_LINKER_FLAGS)" $(ADDITIONAL_GO_BUILD_FLAGS) -o $(OUT_DIR)/gateway github.com/nginxinc/nginx-kubernetes-gateway/cmd/gateway
 endif
 
 .PHONY: build-goreleaser
 build-goreleaser: ## Build the binary using GoReleaser
 	@goreleaser -v || (code=$$?; printf "\033[0;31mError\033[0m: there was a problem with GoReleaser. Follow the docs to install it https://goreleaser.com/install\n"; exit $$code)
-	GOOS=linux GOPATH=$(shell go env GOPATH) GOARCH=$(ARCH) goreleaser build --clean --snapshot --single-target
+	GOOS=linux GOPATH=$(shell go env GOPATH) GOARCH=$(GOARCH) goreleaser build --clean --snapshot --single-target
 
 .PHONY: generate
 generate: ## Run go generate

cmd/gateway/commands.go

@@ -25,7 +25,6 @@ const (
 	gatewayCtrlNameFlag     = "gateway-ctlr-name"
 	gatewayCtrlNameUsageFmt = `The name of the Gateway controller. ` +
 		`The controller name must be of the form: DOMAIN/PATH. The controller's domain is '%s'`
-	gatewayFlag = "gateway"
 )
 
 var (
@@ -38,25 +37,6 @@ var (
 	gatewayClassName = stringValidatingValue{
 		validator: validateResourceName,
 	}
-
-	// Backing values for static subcommand cli flags.
-	updateGCStatus bool
-	disableMetrics bool
-	metricsSecure  bool
-	disableHealth  bool
-
-	metricsListenPort = intValidatingValue{
-		validator: validatePort,
-		value:     9113,
-	}
-	healthListenPort = intValidatingValue{
-		validator: validatePort,
-		value:     8081,
-	}
-	gateway    = namespacedNameValue{}
-	configName = stringValidatingValue{
-		validator: validateResourceName,
-	}
 )
 
 func createRootCommand() *cobra.Command {
@@ -85,6 +65,46 @@ func createRootCommand() *cobra.Command {
 }
 
 func createStaticModeCommand() *cobra.Command {
+	// flag names
+	const (
+		gatewayFlag                = "gateway"
+		configFlag                 = "config"
+		updateGCStatusFlag         = "update-gatewayclass-status"
+		metricsDisableFlag         = "metrics-disable"
+		metricsSecureFlag          = "metrics-secure-serving"
+		metricsPortFlag            = "metrics-port"
+		healthDisableFlag          = "health-disable"
+		healthPortFlag             = "health-port"
+		leaderElectionDisableFlag  = "leader-election-disable"
+		leaderElectionLockNameFlag = "leader-election-lock-name"
+	)
+
+	// flag values
+	var (
+		updateGCStatus bool
+		gateway        = namespacedNameValue{}
+		configName     = stringValidatingValue{
+			validator: validateResourceName,
+		}
+		disableMetrics    bool
+		metricsSecure     bool
+		metricsListenPort = intValidatingValue{
+			validator: validatePort,
+			value:     9113,
+		}
+		disableHealth    bool
+		healthListenPort = intValidatingValue{
+			validator: validatePort,
+			value:     8081,
+		}
+
+		disableLeaderElection  bool
+		leaderElectionLockName = stringValidatingValue{
+			validator: validateResourceName,
+			value:     "nginx-gateway-leader-election-lock",
+		}
+	)
+
 	cmd := &cobra.Command{
 		Use:   "static-mode",
 		Short: "Configure NGINX in the scope of a single Gateway resource",
@@ -109,23 +129,21 @@ func createStaticModeCommand() *cobra.Command {
 				return fmt.Errorf("error validating POD_IP environment variable: %w", err)
 			}
 
-			namespace := os.Getenv("MY_NAMESPACE")
+			namespace := os.Getenv("POD_NAMESPACE")
 			if namespace == "" {
-				return errors.New("MY_NAMESPACE environment variable must be set")
+				return errors.New("POD_NAMESPACE environment variable must be set")
+			}
+
+			podName := os.Getenv("POD_NAME")
+			if podName == "" {
+				return errors.New("POD_NAME environment variable must be set")
 			}
 
 			var gwNsName *types.NamespacedName
 			if cmd.Flags().Changed(gatewayFlag) {
 				gwNsName = &gateway.value
 			}
 
-			metricsConfig := config.MetricsConfig{}
-			if !disableMetrics {
-				metricsConfig.Enabled = true
-				metricsConfig.Port = metricsListenPort.value
-				metricsConfig.Secure = metricsSecure
-			}
-
 			conf := config.Config{
 				GatewayCtlrName:          gatewayCtlrName.value,
 				ConfigName:               configName.String(),
@@ -136,11 +154,20 @@ func createStaticModeCommand() *cobra.Command {
 				Namespace:                namespace,
 				GatewayNsName:            gwNsName,
 				UpdateGatewayClassStatus: updateGCStatus,
-				MetricsConfig:            metricsConfig,
 				HealthConfig: config.HealthConfig{
 					Enabled: !disableHealth,
 					Port:    healthListenPort.value,
 				},
+				MetricsConfig: config.MetricsConfig{
+					Enabled: !disableMetrics,
+					Port:    metricsListenPort.value,
+					Secure:  metricsSecure,
+				},
+				LeaderElection: config.LeaderElection{
+					Enabled:  !disableLeaderElection,
+					LockName: leaderElectionLockName.String(),
+					Identity: podName,
+				},
 			}
 
 			if err := static.StartManager(conf); err != nil {
@@ -163,53 +190,69 @@ func createStaticModeCommand() *cobra.Command {
 
 	cmd.Flags().VarP(
 		&configName,
-		"config",
+		configFlag,
 		"c",
 		`The name of the NginxGateway resource to be used for this controller's dynamic configuration.`+
 			` Lives in the same Namespace as the controller.`,
 	)
 
 	cmd.Flags().BoolVar(
 		&updateGCStatus,
-		"update-gatewayclass-status",
+		updateGCStatusFlag,
 		true,
 		"Update the status of the GatewayClass resource.",
 	)
 
 	cmd.Flags().BoolVar(
 		&disableMetrics,
-		"metrics-disable",
+		metricsDisableFlag,
 		false,
 		"Disable exposing metrics in the Prometheus format.",
 	)
 
 	cmd.Flags().Var(
 		&metricsListenPort,
-		"metrics-port",
+		metricsPortFlag,
 		"Set the port where the metrics are exposed. Format: [1024 - 65535]",
 	)
 
 	cmd.Flags().BoolVar(
 		&metricsSecure,
-		"metrics-secure-serving",
+		metricsSecureFlag,
 		false,
 		"Enable serving metrics via https. By default metrics are served via http."+
 			" Please note that this endpoint will be secured with a self-signed certificate.",
 	)
 
 	cmd.Flags().BoolVar(
 		&disableHealth,
-		"health-disable",
+		healthDisableFlag,
 		false,
 		"Disable running the health probe server.",
 	)
 
 	cmd.Flags().Var(
 		&healthListenPort,
-		"health-port",
+		healthPortFlag,
 		"Set the port where the health probe server is exposed. Format: [1024 - 65535]",
 	)
 
+	cmd.Flags().BoolVar(
+		&disableLeaderElection,
+		leaderElectionDisableFlag,
+		false,
+		"Disable leader election. Leader election is used to avoid multiple replicas of the NGINX Kubernetes Gateway"+
+			" reporting the status of the Gateway API resources. If disabled, "+
+			"all replicas of NGINX Kubernetes Gateway will update the statuses of the Gateway API resources.",
+	)
+
+	cmd.Flags().Var(
+		&leaderElectionLockName,
+		leaderElectionLockNameFlag,
+		"The name of the leader election lock. "+
+			"A Lease object with this name will be created in the same Namespace as the controller.",
+	)
+
 	return cmd
 }
 

cmd/gateway/commands_test.go

@@ -123,6 +123,8 @@ func TestStaticModeCmdFlagValidation(t *testing.T) {
 				"--metrics-secure-serving",
 				"--health-port=8081",
 				"--health-disable",
+				"--leader-election-lock-name=my-lock",
+				"--leader-election-disable=false",
 			},
 			wantErr: false,
 		},
@@ -243,6 +245,22 @@ func TestStaticModeCmdFlagValidation(t *testing.T) {
 			expectedErrPrefix: `invalid argument "999" for "--health-disable" flag: strconv.ParseBool:` +
 				` parsing "999": invalid syntax`,
 		},
+		{
+			name: "leader-election-lock-name is set to invalid string",
+			args: []string{
+				"--leader-election-lock-name=!@#$",
+			},
+			wantErr:           true,
+			expectedErrPrefix: `invalid argument "!@#$" for "--leader-election-lock-name" flag: invalid format`,
+		},
+		{
+			name: "leader-election-disable is set to empty string",
+			args: []string{
+				"--leader-election-disable=",
+			},
+			wantErr:           true,
+			expectedErrPrefix: `invalid argument "" for "--leader-election-disable" flag: strconv.ParseBool`,
+		},
 	}
 
 	for _, test := range tests {

conformance/provisioner/static-deployment.yaml

@@ -10,7 +10,6 @@ metadata:
     app.kubernetes.io/instance: nginx-gateway
     app.kubernetes.io/version: "edge"
 spec:
-  # We only support a single replica for now
   replicas: 1
   selector:
     matchLabels:
@@ -30,15 +29,20 @@ spec:
         - --config=nginx-gateway-config
         - --metrics-disable
         - --health-port=8081
+        - --leader-election-lock-name=nginx-gateway-leader-election
         env:
         - name: POD_IP
           valueFrom:
             fieldRef:
               fieldPath: status.podIP
-        - name: MY_NAMESPACE
+        - name: POD_NAMESPACE
           valueFrom:
             fieldRef:
               fieldPath: metadata.namespace
+        - name: POD_NAME
+          valueFrom:
+            fieldRef:
+              fieldPath: metadata.name
         image: ghcr.io/nginxinc/nginx-kubernetes-gateway:edge
         imagePullPolicy: Always
         name: nginx-gateway