Add option to the Ingress provider to disable IngressClass lookup

docs/content/providers/kubernetes-ingress.md

@@ -344,6 +344,35 @@ providers:
 --providers.kubernetesingress.ingressclass=traefik-internal
 ```
 
+### `disableIngressClassLookup`
+
+_Optional, Default: false_
+
+If the parameter is set to `true`,
+Traefik will not discover IngressClasses in the cluster.
+By doing so, it alleviates the requirement of giving Traefik the rights to look IngressClasses up.
+Furthermore, when this option is set to `true`,
+Traefik is not able to handle Ingresses with IngressClass references,
+therefore such Ingresses will be ignored.
+Please note that annotations are not affected by this option.
+
+```yaml tab="File (YAML)"
+providers:
+  kubernetesIngress:
+    disableIngressClassLookup: true
+    # ...
+```
+
+```toml tab="File (TOML)"
+[providers.kubernetesIngress]
+  disableIngressClassLookup = true
+  # ...
+```
+
+```bash tab="CLI"
+--providers.kubernetesingress.disableingressclasslookup=true
+```
+
 ### `ingressEndpoint`
 
 #### `hostname`

docs/content/reference/static-configuration/cli-ref.md

@@ -735,6 +735,9 @@ Allow ExternalName services. (Default: ```false```)
 `--providers.kubernetesingress.certauthfilepath`:  
 Kubernetes certificate authority file path (not needed for in-cluster client).
 
+`--providers.kubernetesingress.disableingressclasslookup`:  
+Disables the lookup of IngressClasses. (Default: ```false```)
+
 `--providers.kubernetesingress.endpoint`:  
 Kubernetes server endpoint (required for external cluster client).
 

docs/content/reference/static-configuration/env-ref.md

@@ -735,6 +735,9 @@ Allow ExternalName services. (Default: ```false```)
 `TRAEFIK_PROVIDERS_KUBERNETESINGRESS_CERTAUTHFILEPATH`:  
 Kubernetes certificate authority file path (not needed for in-cluster client).
 
+`TRAEFIK_PROVIDERS_KUBERNETESINGRESS_DISABLEINGRESSCLASSLOOKUP`:  
+Disables the lookup of IngressClasses. (Default: ```false```)
+
 `TRAEFIK_PROVIDERS_KUBERNETESINGRESS_ENDPOINT`:  
 Kubernetes server endpoint (required for external cluster client).
 

docs/content/reference/static-configuration/file.toml

@@ -108,6 +108,7 @@
     throttleDuration = "42s"
     allowEmptyServices = true
     allowExternalNameServices = true
+    disableIngressClassLookup = true
     [providers.kubernetesIngress.ingressEndpoint]
       ip = "foobar"
       hostname = "foobar"

docs/content/reference/static-configuration/file.yaml

@@ -117,6 +117,7 @@ providers:
     throttleDuration: 42s
     allowEmptyServices: true
     allowExternalNameServices: true
+    disableIngressClassLookup: true
     ingressEndpoint:
       ip: foobar
       hostname: foobar

integration/fixtures/k8s_ingressclass_disabled.toml

@@ -0,0 +1,18 @@
+[global]
+  checkNewVersion = false
+  sendAnonymousUsage = false
+
+[log]
+  level = "DEBUG"
+  noColor = true
+
+[api]
+  insecure = true
+
+[entryPoints]
+  [entryPoints.web]
+    address = ":8000"
+
+[providers.kubernetesIngress]
+  ingressClass = "traefik-keep"
+  disableIngressClassLookup = true

integration/k8s_test.go

@@ -128,6 +128,17 @@ func (s *K8sSuite) TestIngressclass(c *check.C) {
 	testConfiguration(c, "testdata/rawdata-ingressclass.json", "8080")
 }
 
+func (s *K8sSuite) TestDisableIngressclassLookup(c *check.C) {
+	cmd, display := s.traefikCmd(withConfigFile("fixtures/k8s_ingressclass_disabled.toml"))
+	defer display(c)
+
+	err := cmd.Start()
+	c.Assert(err, checker.IsNil)
+	defer s.killCmd(cmd)
+
+	testConfiguration(c, "testdata/rawdata-ingressclass-disabled.json", "8080")
+}
+
 func testConfiguration(c *check.C, path, apiPort string) {
 	err := try.GetRequest("http://127.0.0.1:"+apiPort+"/api/entrypoints", 20*time.Second, try.BodyContains(`"name":"web"`))
 	c.Assert(err, checker.IsNil)

integration/testdata/rawdata-ingressclass-disabled.json

@@ -0,0 +1,74 @@
+{
+	"routers": {
+		"api@internal": {
+			"entryPoints": [
+				"traefik"
+			],
+			"service": "api@internal",
+			"rule": "PathPrefix(`/api`)",
+			"priority": 2147483646,
+			"status": "enabled",
+			"using": [
+				"traefik"
+			]
+		},
+		"dashboard@internal": {
+			"entryPoints": [
+				"traefik"
+			],
+			"middlewares": [
+				"dashboard_redirect@internal",
+				"dashboard_stripprefix@internal"
+			],
+			"service": "dashboard@internal",
+			"rule": "PathPrefix(`/`)",
+			"priority": 2147483645,
+			"status": "enabled",
+			"using": [
+				"traefik"
+			]
+		}
+	},
+	"middlewares": {
+		"dashboard_redirect@internal": {
+			"redirectRegex": {
+				"regex": "^(http:\\/\\/(\\[[\\w:.]+\\]|[\\w\\._-]+)(:\\d+)?)\\/$",
+				"replacement": "${1}/dashboard/",
+				"permanent": true
+			},
+			"status": "enabled",
+			"usedBy": [
+				"dashboard@internal"
+			]
+		},
+		"dashboard_stripprefix@internal": {
+			"stripPrefix": {
+				"prefixes": [
+					"/dashboard/",
+					"/dashboard"
+				]
+			},
+			"status": "enabled",
+			"usedBy": [
+				"dashboard@internal"
+			]
+		}
+	},
+	"services": {
+		"api@internal": {
+			"status": "enabled",
+			"usedBy": [
+				"api@internal"
+			]
+		},
+		"dashboard@internal": {
+			"status": "enabled",
+			"usedBy": [
+				"dashboard@internal"
+			]
+		},
+		"noop@internal": {
+			"status": "enabled"
+		}
+	}
+}

pkg/provider/kubernetes/ingress/client.go

@@ -57,6 +57,7 @@ type clientWrapper struct {
 	clusterFactory              informers.SharedInformerFactory
 	ingressLabelSelector        string
 	isNamespaceAll              bool
+	disableIngressClassInformer bool
 	watchedNamespaces           []string
 	serverVersion               *version.Version
 }
@@ -214,7 +215,7 @@ func (c *clientWrapper) WatchAll(namespaces []string, stopCh <-chan struct{}) (<
 		}
 	}
 
-	if supportsIngressClass(serverVersion) {
+	if !c.disableIngressClassInformer && supportsIngressClass(serverVersion) {
 		c.clusterFactory = informers.NewSharedInformerFactoryWithOptions(c.clientset, resyncPeriod)
 
 		if supportsNetworkingV1Ingress(serverVersion) {

pkg/provider/kubernetes/ingress/kubernetes.go

@@ -48,6 +48,7 @@ type Provider struct {
 	ThrottleDuration          ptypes.Duration  `description:"Ingress refresh throttle duration" json:"throttleDuration,omitempty" toml:"throttleDuration,omitempty" yaml:"throttleDuration,omitempty" export:"true"`
 	AllowEmptyServices        bool             `description:"Allow creation of services without endpoints." json:"allowEmptyServices,omitempty" toml:"allowEmptyServices,omitempty" yaml:"allowEmptyServices,omitempty" export:"true"`
 	AllowExternalNameServices bool             `description:"Allow ExternalName services." json:"allowExternalNameServices,omitempty" toml:"allowExternalNameServices,omitempty" yaml:"allowExternalNameServices,omitempty" export:"true"`
+	DisableIngressClassLookup bool             `description:"Disables the lookup of IngressClasses." json:"disableIngressClassLookup,omitempty" toml:"disableIngressClassLookup,omitempty" yaml:"disableIngressClassLookup,omitempty" export:"true"`
 	lastConfiguration         safe.Safe
 }
 
@@ -91,6 +92,7 @@ func (p *Provider) newK8sClient(ctx context.Context) (*clientWrapper, error) {
 	}
 
 	cl.ingressLabelSelector = p.LabelSelector
+	cl.disableIngressClassInformer = p.DisableIngressClassLookup
 	return cl, nil
 }
 
@@ -195,7 +197,7 @@ func (p *Provider) loadConfigurationFromIngresses(ctx context.Context, client Cl
 
 	var ingressClasses []*networkingv1.IngressClass
 
-	if supportsIngressClass(serverVersion) {
+	if !p.DisableIngressClassLookup && supportsIngressClass(serverVersion) {
 		ics, err := client.GetIngressClasses()
 		if err != nil {
 			log.Ctx(ctx).Warn().Err(err).Msg("Failed to list ingress classes")

pkg/provider/kubernetes/ingress/kubernetes_test.go

@@ -31,6 +31,7 @@ func TestLoadConfigurationFromIngresses(t *testing.T) {
 		serverVersion             string
 		expected                  *dynamic.Configuration
 		allowEmptyServices        bool
+		disableIngressClassLookup bool
 	}{
 		{
 			desc: "Empty ingresses",
@@ -1392,6 +1393,40 @@ func TestLoadConfigurationFromIngresses(t *testing.T) {
 				},
 			},
 		},
+		{
+			// Duplicate test case with the same fixture as the one above, but with the disableIngressClassLookup option to true.
+			// Showing that disabling the ingressClass discovery still allow the discovery of ingresses with ingress annotation.
+			desc:                      "v18 Ingress with ingress annotation",
+			serverVersion:             "v1.18",
+			disableIngressClassLookup: true,
+			expected: &dynamic.Configuration{
+				TCP: &dynamic.TCPConfiguration{},
+				HTTP: &dynamic.HTTPConfiguration{
+					Middlewares: map[string]*dynamic.Middleware{},
+					Routers: map[string]*dynamic.Router{
+						"testing-bar": {
+							Rule:    "PathPrefix(`/bar`)",
+							Service: "testing-service1-80",
+						},
+					},
+					Services: map[string]*dynamic.Service{
+						"testing-service1-80": {
+							LoadBalancer: &dynamic.ServersLoadBalancer{
+								PassHostHeader: Bool(true),
+								ResponseForwarding: &dynamic.ResponseForwarding{
+									FlushInterval: ptypes.Duration(100 * time.Millisecond),
+								},
+								Servers: []dynamic.Server{
+									{
+										URL: "http://10.10.0.1:8080",
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
 		{
 			desc:          "v18 Ingress with ingressClasses filter",
 			serverVersion: "v1.18",
@@ -1424,6 +1459,22 @@ func TestLoadConfigurationFromIngresses(t *testing.T) {
 				},
 			},
 		},
+		{
+			// Duplicate test case with the same fixture as the one above, but with the disableIngressClassLookup option to true.
+			// Showing that disabling the ingressClass discovery avoid discovering Ingresses with an IngressClass.
+			desc:                      "v18 Ingress with ingressClasses filter",
+			serverVersion:             "v1.18",
+			ingressClass:              "traefik-lb2",
+			disableIngressClassLookup: true,
+			expected: &dynamic.Configuration{
+				TCP: &dynamic.TCPConfiguration{},
+				HTTP: &dynamic.HTTPConfiguration{
+					Middlewares: map[string]*dynamic.Middleware{},
+					Routers:     map[string]*dynamic.Router{},
+					Services:    map[string]*dynamic.Service{},
+				},
+			},
+		},
 		{
 			desc:          "v19 Ingress with prefix pathType",
 			serverVersion: "v1.19",
@@ -1610,6 +1661,39 @@ func TestLoadConfigurationFromIngresses(t *testing.T) {
 				},
 			},
 		},
+		{
+			// Duplicate test case with the same fixture as the one above, but with the disableIngressClassLookup option to true.
+			// Showing that disabling the ingressClass discovery still allow the discovery of ingresses with ingress annotation.
+			desc:          "v19 Ingress with ingress annotation",
+			serverVersion: "v1.19",
+			expected: &dynamic.Configuration{
+				TCP: &dynamic.TCPConfiguration{},
+				HTTP: &dynamic.HTTPConfiguration{
+					Middlewares: map[string]*dynamic.Middleware{},
+					Routers: map[string]*dynamic.Router{
+						"testing-bar": {
+							Rule:    "PathPrefix(`/bar`)",
+							Service: "testing-service1-80",
+						},
+					},
+					Services: map[string]*dynamic.Service{
+						"testing-service1-80": {
+							LoadBalancer: &dynamic.ServersLoadBalancer{
+								PassHostHeader: Bool(true),
+								ResponseForwarding: &dynamic.ResponseForwarding{
+									FlushInterval: ptypes.Duration(100 * time.Millisecond),
+								},
+								Servers: []dynamic.Server{
+									{
+										URL: "http://10.10.0.1:8080",
+									},
+								},
+							},
+						},
+					},
+				},
+			},
+		},
 		{
 			desc:          "v19 Ingress with ingressClass",
 			serverVersion: "v1.19",
@@ -1641,6 +1725,21 @@ func TestLoadConfigurationFromIngresses(t *testing.T) {
 				},
 			},
 		},
+		{
+			// Duplicate test case with the same fixture as the one above, but with the disableIngressClassLookup option to true.
+			// Showing that disabling the ingressClass discovery avoid discovering Ingresses with an IngressClass.
+			desc:                      "v19 Ingress with ingressClass",
+			disableIngressClassLookup: true,
+			serverVersion:             "v1.19",
+			expected: &dynamic.Configuration{
+				TCP: &dynamic.TCPConfiguration{},
+				HTTP: &dynamic.HTTPConfiguration{
+					Middlewares: map[string]*dynamic.Middleware{},
+					Routers:     map[string]*dynamic.Router{},
+					Services:    map[string]*dynamic.Service{},
+				},
+			},
+		},
 		{
 			desc:          "v19 Ingress with ingressClassv1",
 			serverVersion: "v1.19",
@@ -1783,7 +1882,11 @@ func TestLoadConfigurationFromIngresses(t *testing.T) {
 			}
 
 			clientMock := newClientMock(serverVersion, paths...)
-			p := Provider{IngressClass: test.ingressClass, AllowEmptyServices: test.allowEmptyServices}
+			p := Provider{
+				IngressClass:              test.ingressClass,
+				AllowEmptyServices:        test.allowEmptyServices,
+				DisableIngressClassLookup: test.disableIngressClassLookup,
+			}
 			conf := p.loadConfigurationFromIngresses(context.Background(), clientMock)
 
 			assert.Equal(t, test.expected, conf)