chore(dns): remove empty dns port completely (#10338)

Refer to #8640, we have drop usage of empty dns port carefully
and left some property for rollback/downgrade. Nowadays, we gonna
remove it completely

Signed-off-by: Icarus Wu <icaruswu66@qq.com>

app/kuma-dp/cmd/run.go

@@ -183,7 +183,6 @@ func newRunCmd(opts kuma_cmd.RunCmdOpts, rootCtx *RootContext) *cobra.Command {
 			bootstrap, kumaSidecarConfiguration, err := rootCtx.BootstrapGenerator(gracefulCtx, opts.Config.ControlPlane.URL, opts.Config, envoy.BootstrapParams{
 				Dataplane:           opts.Dataplane,
 				DNSPort:             cfg.DNS.EnvoyDNSPort,
-				EmptyDNSPort:        cfg.DNS.CoreDNSEmptyPort,
 				EnvoyVersion:        *envoyVersion,
 				Workdir:             cfg.DataplaneRuntime.SocketDir,
 				AccessLogSocketPath: core_xds.AccessLogSocketName(cfg.DataplaneRuntime.SocketDir, cfg.Dataplane.Name, cfg.Dataplane.Mesh),
@@ -317,14 +316,12 @@ func newRunCmd(opts kuma_cmd.RunCmdOpts, rootCtx *RootContext) *cobra.Command {
 	cmd.PersistentFlags().BoolVar(&cfg.DNS.Enabled, "dns-enabled", cfg.DNS.Enabled, "If true then builtin DNS functionality is enabled and CoreDNS server is started")
 	cmd.PersistentFlags().Uint32Var(&cfg.DNS.EnvoyDNSPort, "dns-envoy-port", cfg.DNS.EnvoyDNSPort, "A port that handles Virtual IP resolving by Envoy. CoreDNS should be configured that it first tries to use this DNS resolver and then the real one")
 	cmd.PersistentFlags().Uint32Var(&cfg.DNS.CoreDNSPort, "dns-coredns-port", cfg.DNS.CoreDNSPort, "A port that handles DNS requests. When transparent proxy is enabled then iptables will redirect DNS traffic to this port.")
-	cmd.PersistentFlags().Uint32Var(&cfg.DNS.CoreDNSEmptyPort, "dns-coredns-empty-port", cfg.DNS.CoreDNSEmptyPort, "A port that always responds with empty NXDOMAIN respond. It is required to implement a fallback to a real DNS.")
 	cmd.PersistentFlags().StringVar(&cfg.DNS.CoreDNSBinaryPath, "dns-coredns-path", cfg.DNS.CoreDNSBinaryPath, "A path to CoreDNS binary.")
 	cmd.PersistentFlags().StringVar(&cfg.DNS.CoreDNSConfigTemplatePath, "dns-coredns-config-template-path", cfg.DNS.CoreDNSConfigTemplatePath, "A path to a CoreDNS config template.")
 	cmd.PersistentFlags().StringVar(&cfg.DNS.ConfigDir, "dns-server-config-dir", cfg.DNS.ConfigDir, "Directory in which DNS Server config will be generated")
 	cmd.PersistentFlags().Uint32Var(&cfg.DNS.PrometheusPort, "dns-prometheus-port", cfg.DNS.PrometheusPort, "A port for exposing Prometheus stats")
 	cmd.PersistentFlags().BoolVar(&cfg.DNS.CoreDNSLogging, "dns-enable-logging", cfg.DNS.CoreDNSLogging, "If true then CoreDNS logging is enabled")
 
-	_ = cmd.PersistentFlags().MarkDeprecated("dns-coredns-empty-port", "It's not used anymore. It will be removed in 2.7.x version")
 	return cmd
 }
 

app/kuma-dp/pkg/dataplane/dnsserver/Corefile

@@ -8,10 +8,3 @@
     errors{{ if .CoreDNSLogging}}
     log{{end}}
 }
-
-.:{{ .CoreDNSEmptyPort }} {
-    template ANY ANY . {
-      rcode NXDOMAIN
-    }{{ if .CoreDNSLogging}}
-    log{{end}}
-}

app/kuma-dp/pkg/dataplane/dnsserver/dnsserver_test.go

@@ -62,7 +62,6 @@ var _ = Describe("DNS Server", func() {
 				DNS: kuma_dp.DNS{
 					Enabled:           true,
 					CoreDNSPort:       16001,
-					CoreDNSEmptyPort:  16002,
 					EnvoyDNSPort:      16002,
 					PrometheusPort:    16003,
 					CoreDNSBinaryPath: filepath.Join("testdata", "binary-mock.exit-0.sh"),
@@ -127,12 +126,6 @@ var _ = Describe("DNS Server", func() {
     prometheus localhost:16003
     errors
 }
-
-.:16002 {
-    template ANY ANY . {
-      rcode NXDOMAIN
-    }
-}
 `))
 		}))
 
@@ -194,7 +187,6 @@ var _ = Describe("DNS Server", func() {
 				DNS: kuma_dp.DNS{
 					Enabled:           true,
 					CoreDNSPort:       16001,
-					CoreDNSEmptyPort:  16002,
 					EnvoyDNSPort:      16002,
 					PrometheusPort:    16003,
 					CoreDNSBinaryPath: filepath.Join("testdata", "binary-mock.exit-0.sh"),
@@ -261,13 +253,6 @@ var _ = Describe("DNS Server", func() {
     errors
     log
 }
-
-.:16002 {
-    template ANY ANY . {
-      rcode NXDOMAIN
-    }
-    log
-}
 `))
 		}))
 	})

app/kuma-dp/pkg/dataplane/envoy/envoy.go

@@ -30,7 +30,6 @@ var runLog = core.Log.WithName("kuma-dp").WithName("run").WithName("envoy")
 type BootstrapParams struct {
 	Dataplane           rest.Resource
 	DNSPort             uint32
-	EmptyDNSPort        uint32
 	EnvoyVersion        EnvoyVersion
 	DynamicMetadata     map[string]string
 	Workdir             string

app/kuma-dp/pkg/dataplane/envoy/remote_bootstrap.go

@@ -179,7 +179,6 @@ func (b *remoteBootstrap) requestForBootstrap(ctx context.Context, client *http.
 		},
 		DynamicMetadata:     params.DynamicMetadata,
 		DNSPort:             params.DNSPort,
-		EmptyDNSPort:        params.EmptyDNSPort,
 		OperatingSystem:     b.operatingSystem,
 		Features:            b.features,
 		Resources:           resources,

pkg/config/app/kuma-dp/config.go

@@ -41,7 +41,6 @@ var DefaultConfig = func() Config {
 			Enabled:                   true,
 			CoreDNSPort:               15053,
 			EnvoyDNSPort:              15054,
-			CoreDNSEmptyPort:          15055,
 			CoreDNSBinaryPath:         "coredns",
 			CoreDNSConfigTemplatePath: "",
 			ConfigDir:                 "", // if left empty, a temporary directory will be generated automatically
@@ -353,8 +352,6 @@ type DNS struct {
 	Enabled bool `json:"enabled,omitempty" envconfig:"kuma_dns_enabled"`
 	// CoreDNSPort defines a port that handles DNS requests. When transparent proxy is enabled then iptables will redirect DNS traffic to this port.
 	CoreDNSPort uint32 `json:"coreDnsPort,omitempty" envconfig:"kuma_dns_core_dns_port"`
-	// CoreDNSEmptyPort defines a port that always responds with empty NXDOMAIN respond. It is required to implement a fallback to a real DNS
-	CoreDNSEmptyPort uint32 `json:"coreDnsEmptyPort,omitempty" envconfig:"kuma_dns_core_dns_empty_port"`
 	// EnvoyDNSPort defines a port that handles Virtual IP resolving by Envoy. CoreDNS should be configured that it first tries to use this DNS resolver and then the real one.
 	EnvoyDNSPort uint32 `json:"envoyDnsPort,omitempty" envconfig:"kuma_dns_envoy_dns_port"`
 	// CoreDNSBinaryPath defines a path to CoreDNS binary.
@@ -376,9 +373,6 @@ func (d *DNS) Validate() error {
 	if d.CoreDNSPort > 65353 {
 		return errors.New(".CoreDNSPort has to be in [0, 65353] range")
 	}
-	if d.CoreDNSEmptyPort > 65353 {
-		return errors.New(".CoreDNSEmptyPort has to be in [0, 65353] range")
-	}
 	if d.EnvoyDNSPort > 65353 {
 		return errors.New(".EnvoyDNSPort has to be in [0, 65353] range")
 	}

pkg/config/app/kuma-dp/config_test.go

@@ -64,7 +64,6 @@ var _ = Describe("Config", func() {
 				"KUMA_DATAPLANE_RUNTIME_DYNAMIC_CONFIGURATION_REFRESH_INTERVAL": "5s",
 				"KUMA_DNS_ENABLED":                                              "true",
 				"KUMA_DNS_CORE_DNS_PORT":                                        "5300",
-				"KUMA_DNS_CORE_DNS_EMPTY_PORT":                                  "5301",
 				"KUMA_DNS_ENVOY_DNS_PORT":                                       "5302",
 				"KUMA_DNS_CORE_DNS_BINARY_PATH":                                 "/tmp/coredns",
 				"KUMA_DNS_CORE_DNS_CONFIG_TEMPLATE_PATH":                        "/tmp/Corefile",
@@ -99,7 +98,6 @@ var _ = Describe("Config", func() {
 			Expect(cfg.DataplaneRuntime.DynamicConfiguration.RefreshInterval.Duration).To(Equal(5 * time.Second))
 			Expect(cfg.DNS.Enabled).To(BeTrue())
 			Expect(cfg.DNS.CoreDNSPort).To(Equal(uint32(5300)))
-			Expect(cfg.DNS.CoreDNSEmptyPort).To(Equal(uint32(5301)))
 			Expect(cfg.DNS.EnvoyDNSPort).To(Equal(uint32(5302)))
 			Expect(cfg.DNS.CoreDNSBinaryPath).To(Equal("/tmp/coredns"))
 			Expect(cfg.DNS.CoreDNSConfigTemplatePath).To(Equal("/tmp/Corefile"))

pkg/config/app/kuma-dp/testdata/default-config.golden.yaml

@@ -16,7 +16,6 @@ dataplaneRuntime:
   resources: {}
 dns:
   coreDnsBinaryPath: coredns
-  coreDnsEmptyPort: 15055
   coreDnsPort: 15053
   enabled: true
   envoyDnsPort: 15054

pkg/core/xds/metadata.go

@@ -22,7 +22,6 @@ const (
 	FieldDataplaneAdminPort         = "dataplane.admin.port"
 	FieldDataplaneAdminAddress      = "dataplane.admin.address"
 	FieldDataplaneDNSPort           = "dataplane.dns.port"
-	FieldDataplaneDNSEmptyPort      = "dataplane.dns.empty.port"
 	FieldDataplaneDataplaneResource = "dataplane.resource"
 	FieldDynamicMetadata            = "dynamicMetadata"
 	FieldDataplaneProxyType         = "dataplane.proxyType"
@@ -56,7 +55,6 @@ type DataplaneMetadata struct {
 	AdminPort           uint32
 	AdminAddress        string
 	DNSPort             uint32
-	EmptyDNSPort        uint32
 	DynamicMetadata     map[string]string
 	ProxyType           mesh_proto.ProxyType
 	Version             *mesh_proto.Version
@@ -133,13 +131,6 @@ func (m *DataplaneMetadata) GetDNSPort() uint32 {
 	return m.DNSPort
 }
 
-func (m *DataplaneMetadata) GetEmptyDNSPort() uint32 {
-	if m == nil {
-		return 0
-	}
-	return m.EmptyDNSPort
-}
-
 func (m *DataplaneMetadata) GetDynamicMetadata(key string) string {
 	if m == nil || m.DynamicMetadata == nil {
 		return ""
@@ -168,7 +159,6 @@ func DataplaneMetadataFromXdsMetadata(xdsMetadata *structpb.Struct, tmpDir strin
 	metadata.AdminPort = uint32Metadata(xdsMetadata, FieldDataplaneAdminPort)
 	metadata.AdminAddress = xdsMetadata.Fields[FieldDataplaneAdminAddress].GetStringValue()
 	metadata.DNSPort = uint32Metadata(xdsMetadata, FieldDataplaneDNSPort)
-	metadata.EmptyDNSPort = uint32Metadata(xdsMetadata, FieldDataplaneDNSEmptyPort)
 	if value := xdsMetadata.Fields[FieldDataplaneDataplaneResource]; value != nil {
 		res, err := rest.YAML.UnmarshalCore([]byte(value.GetStringValue()))
 		if err != nil {

pkg/core/xds/metadata_test.go

@@ -54,11 +54,6 @@ var _ = Describe("DataplaneMetadataFromXdsMetadata", func() {
 							StringValue: "8000",
 						},
 					},
-					"dataplane.dns.empty.port": {
-						Kind: &structpb.Value_StringValue{
-							StringValue: "8001",
-						},
-					},
 					"accessLogSocketPath": {
 						Kind: &structpb.Value_StringValue{
 							StringValue: "/tmp/logs",
@@ -79,7 +74,6 @@ var _ = Describe("DataplaneMetadataFromXdsMetadata", func() {
 			expected: xds.DataplaneMetadata{
 				AdminPort:           1234,
 				DNSPort:             8000,
-				EmptyDNSPort:        8001,
 				AccessLogSocketPath: "/tmp/logs",
 				MetricsSocketPath:   "/tmp/metrics",
 				SystemCaPath:        "/etc/certs/cert.pem",

pkg/envoy/admin/testdata/full_config.json

@@ -25,7 +25,6 @@
             "dynamicMetadata": {
               "version.dependencies.coredns": "1.8.3"
             },
-            "dataplane.dns.empty.port": "15055",
             "dataplane.admin.port": "6606",
             "dataplane.resource": "{\"type\":\"Dataplane\",\"mesh\":\"default\",\"name\":\"backend-1\",\"creationTime\":\"0001-01-01T00:00:00Z\",\"modificationTime\":\"0001-01-01T00:00:00Z\",\"networking\":{\"address\":\"127.0.0.1\",\"inbound\":[{\"port\":10010,\"servicePort\":10011,\"tags\":{\"kuma.io/protocol\":\"tcp\",\"kuma.io/region\":\"reg1\",\"kuma.io/service\":\"backend\",\"kuma.io/sub-zone\":\"subzone1\",\"version\":\"1\"}}],\"outbound\":[{\"port\":10006,\"tags\":{\"kuma.io/service\":\"gateway\"}}],\"admin\":{\"port\":6606}}}"
           },

pkg/envoy/admin/testdata/golden.full_config.json

@@ -25,7 +25,6 @@
             "dynamicMetadata": {
               "version.dependencies.coredns": "1.8.3"
             },
-            "dataplane.dns.empty.port": "15055",
             "dataplane.admin.port": "6606",
             "dataplane.resource": "{\"type\":\"Dataplane\",\"mesh\":\"default\",\"name\":\"backend-1\",\"creationTime\":\"0001-01-01T00:00:00Z\",\"modificationTime\":\"0001-01-01T00:00:00Z\",\"networking\":{\"address\":\"127.0.0.1\",\"inbound\":[{\"port\":10010,\"servicePort\":10011,\"tags\":{\"kuma.io/protocol\":\"tcp\",\"kuma.io/region\":\"reg1\",\"kuma.io/service\":\"backend\",\"kuma.io/sub-zone\":\"subzone1\",\"version\":\"1\"}}],\"outbound\":[{\"port\":10006,\"tags\":{\"kuma.io/service\":\"gateway\"}}],\"admin\":{\"port\":6606}}}"
           },

pkg/envoy/admin/testdata/golden.no_hds.json

@@ -25,7 +25,6 @@
             "dynamicMetadata": {
               "version.dependencies.coredns": "1.8.3"
             },
-            "dataplane.dns.empty.port": "15055",
             "dataplane.admin.port": "6606",
             "dataplane.resource": "{\"type\":\"Dataplane\",\"mesh\":\"default\",\"name\":\"backend-1\",\"creationTime\":\"0001-01-01T00:00:00Z\",\"modificationTime\":\"0001-01-01T00:00:00Z\",\"networking\":{\"address\":\"127.0.0.1\",\"inbound\":[{\"port\":10010,\"servicePort\":10011,\"tags\":{\"kuma.io/protocol\":\"tcp\",\"kuma.io/region\":\"reg1\",\"kuma.io/service\":\"backend\",\"kuma.io/sub-zone\":\"subzone1\",\"version\":\"1\"}}],\"outbound\":[{\"port\":10006,\"tags\":{\"kuma.io/service\":\"gateway\"}}],\"admin\":{\"port\":6606}}}"
           },

pkg/envoy/admin/testdata/no_hds.json

@@ -25,7 +25,6 @@
             "dynamicMetadata": {
               "version.dependencies.coredns": "1.8.3"
             },
-            "dataplane.dns.empty.port": "15055",
             "dataplane.admin.port": "6606",
             "dataplane.resource": "{\"type\":\"Dataplane\",\"mesh\":\"default\",\"name\":\"backend-1\",\"creationTime\":\"0001-01-01T00:00:00Z\",\"modificationTime\":\"0001-01-01T00:00:00Z\",\"networking\":{\"address\":\"127.0.0.1\",\"inbound\":[{\"port\":10010,\"servicePort\":10011,\"tags\":{\"kuma.io/protocol\":\"tcp\",\"kuma.io/region\":\"reg1\",\"kuma.io/service\":\"backend\",\"kuma.io/sub-zone\":\"subzone1\",\"version\":\"1\"}}],\"outbound\":[{\"port\":10006,\"tags\":{\"kuma.io/service\":\"gateway\"}}],\"admin\":{\"port\":6606}}}"
           },

pkg/plugins/runtime/k8s/containers/factory.go

@@ -278,11 +278,6 @@ func (i *DataplaneProxyFactory) sidecarEnvVars(mesh string, podAnnotations map[s
 			Value: strconv.FormatInt(int64(i.BuiltinDNS.Port), 10),
 		}
 
-		envVars["KUMA_DNS_CORE_DNS_EMPTY_PORT"] = kube_core.EnvVar{
-			Name:  "KUMA_DNS_CORE_DNS_EMPTY_PORT",
-			Value: strconv.FormatInt(int64(i.BuiltinDNS.Port+1), 10),
-		}
-
 		envVars["KUMA_DNS_ENVOY_DNS_PORT"] = kube_core.EnvVar{
 			Name:  "KUMA_DNS_ENVOY_DNS_PORT",
 			Value: strconv.FormatInt(int64(i.BuiltinDNS.Port+2), 10),

pkg/plugins/runtime/k8s/webhooks/injector/testdata/inject.23.golden.yaml

@@ -67,8 +67,6 @@ spec:
       value: /var/run/secrets/kubernetes.io/serviceaccount/token
     - name: KUMA_DNS_CORE_DNS_BINARY_PATH
       value: coredns
-    - name: KUMA_DNS_CORE_DNS_EMPTY_PORT
-      value: "25054"
     - name: KUMA_DNS_CORE_DNS_PORT
       value: "25053"
     - name: KUMA_DNS_ENABLED

pkg/plugins/runtime/k8s/webhooks/injector/testdata/inject.24.golden.yaml

@@ -68,8 +68,6 @@ spec:
       value: /var/run/secrets/kubernetes.io/serviceaccount/token
     - name: KUMA_DNS_CORE_DNS_BINARY_PATH
       value: coredns
-    - name: KUMA_DNS_CORE_DNS_EMPTY_PORT
-      value: "25054"
     - name: KUMA_DNS_CORE_DNS_PORT
       value: "25053"
     - name: KUMA_DNS_ENABLED

pkg/plugins/runtime/k8s/webhooks/injector/testdata/inject.25.golden.yaml

@@ -67,8 +67,6 @@ spec:
       value: /var/run/secrets/kubernetes.io/serviceaccount/token
     - name: KUMA_DNS_CORE_DNS_BINARY_PATH
       value: coredns
-    - name: KUMA_DNS_CORE_DNS_EMPTY_PORT
-      value: "25054"
     - name: KUMA_DNS_CORE_DNS_PORT
       value: "25053"
     - name: KUMA_DNS_ENABLED

pkg/plugins/runtime/k8s/webhooks/injector/testdata/inject.29.golden.yaml

@@ -65,8 +65,6 @@ spec:
       value: /var/run/secrets/kubernetes.io/serviceaccount/token
     - name: KUMA_DNS_CORE_DNS_BINARY_PATH
       value: coredns
-    - name: KUMA_DNS_CORE_DNS_EMPTY_PORT
-      value: "25054"
     - name: KUMA_DNS_CORE_DNS_PORT
       value: "25053"
     - name: KUMA_DNS_ENABLED

pkg/plugins/runtime/k8s/webhooks/injector/testdata/inject.sidecar-feature.23.golden.yaml

@@ -125,8 +125,6 @@ spec:
       value: /var/run/secrets/kubernetes.io/serviceaccount/token
     - name: KUMA_DNS_CORE_DNS_BINARY_PATH
       value: coredns
-    - name: KUMA_DNS_CORE_DNS_EMPTY_PORT
-      value: "25054"
     - name: KUMA_DNS_CORE_DNS_PORT
       value: "25053"
     - name: KUMA_DNS_ENABLED

pkg/plugins/runtime/k8s/webhooks/injector/testdata/inject.sidecar-feature.24.golden.yaml

@@ -126,8 +126,6 @@ spec:
       value: /var/run/secrets/kubernetes.io/serviceaccount/token
     - name: KUMA_DNS_CORE_DNS_BINARY_PATH
       value: coredns
-    - name: KUMA_DNS_CORE_DNS_EMPTY_PORT
-      value: "25054"
     - name: KUMA_DNS_CORE_DNS_PORT
       value: "25053"
     - name: KUMA_DNS_ENABLED

pkg/plugins/runtime/k8s/webhooks/injector/testdata/inject.sidecar-feature.25.golden.yaml

@@ -125,8 +125,6 @@ spec:
       value: /var/run/secrets/kubernetes.io/serviceaccount/token
     - name: KUMA_DNS_CORE_DNS_BINARY_PATH
       value: coredns
-    - name: KUMA_DNS_CORE_DNS_EMPTY_PORT
-      value: "25054"
     - name: KUMA_DNS_CORE_DNS_PORT
       value: "25053"
     - name: KUMA_DNS_ENABLED

pkg/plugins/runtime/k8s/webhooks/injector/testdata/inject.sidecar-feature.29.golden.yaml

@@ -119,8 +119,6 @@ spec:
       value: /var/run/secrets/kubernetes.io/serviceaccount/token
     - name: KUMA_DNS_CORE_DNS_BINARY_PATH
       value: coredns
-    - name: KUMA_DNS_CORE_DNS_EMPTY_PORT
-      value: "25054"
     - name: KUMA_DNS_CORE_DNS_PORT
       value: "25053"
     - name: KUMA_DNS_ENABLED

pkg/xds/bootstrap/generator.go

@@ -116,7 +116,6 @@ func (b *bootstrapGenerator) Generate(ctx context.Context, request types.Bootstr
 		},
 		DynamicMetadata:     request.DynamicMetadata,
 		DNSPort:             request.DNSPort,
-		EmptyDNSPort:        request.EmptyDNSPort,
 		ProxyType:           request.ProxyType,
 		Features:            request.Features,
 		Resources:           request.Resources,

pkg/xds/bootstrap/generator_test.go

@@ -172,7 +172,6 @@ var _ = Describe("bootstrapGenerator", func() {
 				DataplaneToken: "token",
 				Version:        defaultVersion,
 				DNSPort:        53001,
-				EmptyDNSPort:   53002,
 			},
 			expectedConfigFile: "generator.default-config.golden.yaml",
 			hdsEnabled:         true,
@@ -387,7 +386,6 @@ var _ = Describe("bootstrapGenerator", func() {
 				DataplaneToken: "token",
 				Version:        defaultVersion,
 				DNSPort:        53001,
-				EmptyDNSPort:   53002,
 			},
 			expectedConfigFile: "generator.default-config.golden.yaml",
 			hdsEnabled:         true,
@@ -411,7 +409,6 @@ var _ = Describe("bootstrapGenerator", func() {
 				DataplaneToken:     "token",
 				Version:            defaultVersion,
 				DNSPort:            53001,
-				EmptyDNSPort:       53002,
 				DataplaneTokenPath: "/path/to/file",
 				MetricsResources: types.MetricsResources{
 					CertPath: "/path/cert/pem",
@@ -457,7 +454,6 @@ var _ = Describe("bootstrapGenerator", func() {
 				DataplaneToken:     "token",
 				Version:            defaultVersion,
 				DNSPort:            53001,
-				EmptyDNSPort:       53002,
 				DataplaneTokenPath: "/path/to/file",
 			},
 			expectedConfigFile: "generator.gateway.golden.yaml",

pkg/xds/bootstrap/parameters.go

@@ -47,7 +47,6 @@ type configParameters struct {
 	HdsEnabled          bool
 	DynamicMetadata     map[string]string
 	DNSPort             uint32
-	EmptyDNSPort        uint32
 	ProxyType           string
 	Features            []string
 	IsGatewayDataplane  bool

pkg/xds/bootstrap/template_v3.go

@@ -336,9 +336,6 @@ func genConfig(parameters configParameters, proxyConfig xds.Proxy, enableReloada
 	if parameters.DNSPort != 0 {
 		res.Node.Metadata.Fields[core_xds.FieldDataplaneDNSPort] = util_proto.MustNewValueForStruct(strconv.Itoa(int(parameters.DNSPort)))
 	}
-	if parameters.EmptyDNSPort != 0 {
-		res.Node.Metadata.Fields[core_xds.FieldDataplaneDNSEmptyPort] = util_proto.MustNewValueForStruct(strconv.Itoa(int(parameters.EmptyDNSPort)))
-	}
 	if parameters.ProxyType != "" {
 		res.Node.Metadata.Fields[core_xds.FieldDataplaneProxyType] = util_proto.MustNewValueForStruct(parameters.ProxyType)
 	}

pkg/xds/bootstrap/testdata/corefile.template

@@ -10,10 +10,4 @@
     alternate NOTIMP,FORMERR,NXDOMAIN,SERVFAIL,REFUSED . /etc/resolv.conf
     prometheus localhost:{{ .PrometheusPort }}
     errors
-}
-
-.:{{ .CoreDNSEmptyPort }} {
-    template ANY ANY . {
-      rcode NXDOMAIN
-    }
 }

pkg/xds/bootstrap/testdata/generator.default-config-token-path.golden.yaml

@@ -72,7 +72,6 @@ node:
     accessLogSocketPath: /tmp/kuma-al-name.namespace-mesh.sock
     dataplane.admin.address: 127.0.0.1
     dataplane.admin.port: "1234"
-    dataplane.dns.empty.port: "53002"
     dataplane.dns.port: "53001"
     dataplane.proxyType: dataplane
     features: []