Add configuration to disable external name service feature

cmd/nginx/flags.go

@@ -126,6 +126,9 @@ Requires the update-status parameter.`)
 		enableSSLPassthrough = flags.Bool("enable-ssl-passthrough", false,
 			`Enable SSL Passthrough.`)
 
+		disableServiceExternalName = flags.Bool("disable-svc-external-name", false,
+			`Disable support for Services of type ExternalName`)
+
 		annotationsPrefix = flags.String("annotations-prefix", parser.DefaultAnnotationsPrefix,
 			`Prefix of the Ingress annotations specific to the NGINX controller.`)
 
@@ -264,28 +267,29 @@ https://blog.maxmind.com/2019/12/18/significant-changes-to-accessing-and-using-g
 	ngx_config.EnableSSLChainCompletion = *enableSSLChainCompletion
 
 	config := &controller.Configuration{
-		APIServerHost:          *apiserverHost,
-		KubeConfigFile:         *kubeConfigFile,
-		UpdateStatus:           *updateStatus,
-		ElectionID:             *electionID,
-		EnableProfiling:        *profiling,
-		EnableMetrics:          *enableMetrics,
-		MetricsPerHost:         *metricsPerHost,
-		MonitorMaxBatchSize:    *monitorMaxBatchSize,
-		EnableSSLPassthrough:   *enableSSLPassthrough,
-		ResyncPeriod:           *resyncPeriod,
-		DefaultService:         *defaultSvc,
-		Namespace:              *watchNamespace,
-		ConfigMapName:          *configMap,
-		TCPConfigMapName:       *tcpConfigMapName,
-		UDPConfigMapName:       *udpConfigMapName,
-		DefaultSSLCertificate:  *defSSLCertificate,
-		PublishService:         *publishSvc,
-		PublishStatusAddress:   *publishStatusAddress,
-		UpdateStatusOnShutdown: *updateStatusOnShutdown,
-		ShutdownGracePeriod:    *shutdownGracePeriod,
-		UseNodeInternalIP:      *useNodeInternalIP,
-		SyncRateLimit:          *syncRateLimit,
+		APIServerHost:              *apiserverHost,
+		KubeConfigFile:             *kubeConfigFile,
+		UpdateStatus:               *updateStatus,
+		ElectionID:                 *electionID,
+		EnableProfiling:            *profiling,
+		EnableMetrics:              *enableMetrics,
+		MetricsPerHost:             *metricsPerHost,
+		MonitorMaxBatchSize:        *monitorMaxBatchSize,
+		DisableServiceExternalName: *disableServiceExternalName,
+		EnableSSLPassthrough:       *enableSSLPassthrough,
+		ResyncPeriod:               *resyncPeriod,
+		DefaultService:             *defaultSvc,
+		Namespace:                  *watchNamespace,
+		ConfigMapName:              *configMap,
+		TCPConfigMapName:           *tcpConfigMapName,
+		UDPConfigMapName:           *udpConfigMapName,
+		DefaultSSLCertificate:      *defSSLCertificate,
+		PublishService:             *publishSvc,
+		PublishStatusAddress:       *publishStatusAddress,
+		UpdateStatusOnShutdown:     *updateStatusOnShutdown,
+		ShutdownGracePeriod:        *shutdownGracePeriod,
+		UseNodeInternalIP:          *useNodeInternalIP,
+		SyncRateLimit:              *syncRateLimit,
 		ListenPorts: &ngx_config.ListenPorts{
 			Default:  *defServerPort,
 			Health:   *healthzPort,

go.mod

@@ -17,7 +17,7 @@ require (
 	github.com/mitchellh/mapstructure v1.3.2
 	github.com/moul/pb v0.0.0-20180404114147-54bdd96e6a52
 	github.com/ncabatoff/process-exporter v0.7.2
-	github.com/onsi/ginkgo v1.14.1
+	github.com/onsi/ginkgo v1.16.4
 	github.com/opencontainers/runc v1.0.0-rc92
 	github.com/pkg/errors v0.9.1
 	github.com/pmezard/go-difflib v1.0.0

go.sum

@@ -240,6 +240,8 @@ github.com/go-openapi/validate v0.19.2/go.mod h1:1tRCw7m3jtI8eNWEEliiAqUIcBztB2K
 github.com/go-openapi/validate v0.19.8/go.mod h1:8DJv2CVJQ6kGNpFW6eV9N3JviE1C85nY1c2z52x1Gk4=
 github.com/go-sql-driver/mysql v1.4.0/go.mod h1:zAC/RDZ24gD3HViQzih4MyKcchzm+sOG5ZlKdlhCg5w=
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
+github.com/go-task/slim-sprig v0.0.0-20210107165309-348f09dbbbc0 h1:p104kn46Q8WdvHunIJ9dAyjPVtrBPhSr3KT2yUst43I=
+github.com/go-task/slim-sprig v0.0.0-20210107165309-348f09dbbbc0/go.mod h1:fyg7847qk6SyHyPtNmDHnmrv/HOrqktSC+C9fM+CJOE=
 github.com/gobuffalo/here v0.6.0/go.mod h1:wAG085dHOYqUpf+Ap+WOdrPTp5IYcDAs/x7PLa8Y5fM=
 github.com/godbus/dbus/v5 v5.0.3 h1:ZqHaoEF7TBzh4jzPmqVhE/5A1z9of6orkAe5uHoAeME=
 github.com/godbus/dbus/v5 v5.0.3/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
@@ -484,6 +486,8 @@ github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e h1:fD57ERR4JtEqsWb
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
 github.com/nxadm/tail v1.4.4 h1:DQuhQpB1tVlglWS2hLQ5OV6B5r8aGxSrPc5Qo6uTN78=
 github.com/nxadm/tail v1.4.4/go.mod h1:kenIhsEOeOJmVchQTgglprH7qJGnHDVpk1VPCcaMI8A=
+github.com/nxadm/tail v1.4.8 h1:nPr65rt6Y5JFSKQO7qToXr7pePgD6Gwiw05lkbyAQTE=
+github.com/nxadm/tail v1.4.8/go.mod h1:+ncqLTQzXmGhMZNUePPaPqPvBxHAIsmXswZKocGu+AU=
 github.com/oklog/oklog v0.3.2/go.mod h1:FCV+B7mhrz4o+ueLpx+KqkyXRGMWOYEvfiXtdGtbWGs=
 github.com/oklog/run v1.0.0/go.mod h1:dlhp/R75TPv97u0XWUtDeV/lRKWPKSdTuV0TZvrmrQA=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=
@@ -496,6 +500,8 @@ github.com/onsi/ginkgo v1.11.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+
 github.com/onsi/ginkgo v1.12.1/go.mod h1:zj2OWP4+oCPe1qIXoGWkgMRwljMUYCdkwsT2108oapk=
 github.com/onsi/ginkgo v1.14.1 h1:jMU0WaQrP0a/YAEq8eJmJKjBoMs+pClEr1vDMlM/Do4=
 github.com/onsi/ginkgo v1.14.1/go.mod h1:iSB4RoI2tjJc9BBv4NKIKWKya62Rps+oPG/Lv9klQyY=
+github.com/onsi/ginkgo v1.16.4 h1:29JGrr5oVBm5ulCWet69zQkzWipVXIol6ygQUe/EzNc=
+github.com/onsi/ginkgo v1.16.4/go.mod h1:dX+/inL/fNMqNlz0e9LfyB9TswhZpCVdJM/Z6Vvnwo0=
 github.com/onsi/gomega v0.0.0-20170829124025-dcabb60a477c/go.mod h1:C1qb7wdrVGGVU+Z6iS04AVkA3Q65CEZX59MT0QO5uiA=
 github.com/onsi/gomega v1.4.3/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
 github.com/onsi/gomega v1.7.0/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
@@ -842,6 +848,7 @@ golang.org/x/sys v0.0.0-20200831180312-196b9ba8737a/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201112073958-5cba982894dd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210112080510-489259a85091/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210119212857-b64e53b001e4/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210225134936-a50acf3fe073 h1:8qxJSnu+7dRq6upnbntrmriWByIakBuct5OM/MdQC1M=
 golang.org/x/sys v0.0.0-20210225134936-a50acf3fe073/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
@@ -909,6 +916,7 @@ golang.org/x/tools v0.0.0-20200304193943-95d2e580d8eb/go.mod h1:o4KQGtdN14AW+yjs
 golang.org/x/tools v0.0.0-20200505023115-26f46d2f7ef8/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/tools v0.0.0-20200616133436-c1934b75d054/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
 golang.org/x/tools v0.0.0-20200619180055-7c47624df98f/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
+golang.org/x/tools v0.0.0-20201224043029-2b0845dc783e/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
 golang.org/x/tools v0.1.0 h1:po9/4sTYwZU9lPhi1tOrb4hCv3qrhiQ77LZfGa2OjwY=
 golang.org/x/tools v0.1.0/go.mod h1:xkSsbof2nBLbhDlRMhhhyNLN/zl3eTqcnHD5viDpcZ0=

internal/ingress/controller/controller.go

@@ -85,6 +85,8 @@ type Configuration struct {
 
 	ListenPorts *ngx_config.ListenPorts
 
+	DisableServiceExternalName bool
+
 	EnableSSLPassthrough bool
 
 	EnableProfiling bool
@@ -968,6 +970,10 @@ func (n *NGINXController) serviceEndpoints(svcKey, backendPort string) ([]ingres
 
 	// Ingress with an ExternalName Service and no port defined for that Service
 	if svc.Spec.Type == apiv1.ServiceTypeExternalName {
+		if n.cfg.DisableServiceExternalName {
+			klog.Warningf("Service %q of type ExternalName not allowed due to Ingress configuration.", svcKey)
+			return upstreams, nil
+		}
 		servicePort := externalNamePorts(backendPort, svc)
 		endps := getEndpoints(svc, servicePort, apiv1.ProtocolTCP, n.store.GetServiceEndpoints)
 		if len(endps) == 0 {

test/e2e/settings/disable_service_external_name.go

@@ -0,0 +1,95 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package settings
+
+import (
+	"context"
+	"net/http"
+	"strings"
+
+	"github.com/gavv/httpexpect/v2"
+	"github.com/onsi/ginkgo"
+	"github.com/stretchr/testify/assert"
+	appsv1 "k8s.io/api/apps/v1"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	"k8s.io/ingress-nginx/test/e2e/framework"
+)
+
+var _ = framework.IngressNginxDescribe("[Flag] disable-service-external-name", func() {
+	f := framework.NewDefaultFramework("disabled-service-external-name")
+
+	ginkgo.BeforeEach(func() {
+		f.NewEchoDeploymentWithReplicas(2)
+
+		err := f.UpdateIngressControllerDeployment(func(deployment *appsv1.Deployment) error {
+			args := deployment.Spec.Template.Spec.Containers[0].Args
+			args = append(args, "--disable-svc-external-name=true")
+			deployment.Spec.Template.Spec.Containers[0].Args = args
+			_, err := f.KubeClientSet.AppsV1().Deployments(f.Namespace).Update(context.TODO(), deployment, metav1.UpdateOptions{})
+
+			return err
+		})
+		assert.Nil(ginkgo.GinkgoT(), err, "updating ingress controller deployment flags")
+	})
+
+	ginkgo.It("should ignore services of external-name type", func() {
+
+		nonexternalhost := "echo-svc.com"
+
+		externalhost := "echo-external-svc.com"
+		svcexternal := &corev1.Service{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "external",
+				Namespace: f.Namespace,
+			},
+			Spec: corev1.ServiceSpec{
+				ExternalName: "httpbin.org",
+				Type:         corev1.ServiceTypeExternalName,
+			},
+		}
+		f.EnsureService(svcexternal)
+
+		ingexternal := framework.NewSingleIngress(externalhost, "/", externalhost, f.Namespace, "external", 80, nil)
+		f.EnsureIngress(ingexternal)
+
+		ing := framework.NewSingleIngress(nonexternalhost, "/", nonexternalhost, f.Namespace, framework.EchoService, 80, nil)
+		f.EnsureIngress(ing)
+
+		f.WaitForNginxServer(nonexternalhost, func(cfg string) bool {
+			return strings.Contains(cfg, "server_name echo-svc.com")
+		})
+
+		f.WaitForNginxServer(externalhost, func(cfg string) bool {
+			return strings.Contains(cfg, "server_name echo-external-svc.com")
+		})
+
+		f.HTTPTestClient().
+			GET("/").
+			WithHeader("Host", nonexternalhost).
+			Expect().
+			Status(http.StatusOK)
+
+		f.HTTPTestClient().
+			GET("/").
+			WithHeader("Host", externalhost).
+			Expect().
+			StatusRange(httpexpect.Status5xx)
+
+	})
+})