IngressRoute: add an option to disable cross-namespace routing

Co-authored-by: Jean-Baptiste Doumenjou <925513+jbdoumenjou@users.noreply.github.com>

docs/content/providers/kubernetes-crd.md

@@ -250,6 +250,34 @@ providers:
 --providers.kubernetescrd.throttleDuration=10s
 ```
 
+### `allowCrossNamespace`
+
+_Optional, Default: true_
+
+```toml tab="File (TOML)"
+[providers.kubernetesCRD]
+  allowCrossNamespace = false
+  # ...
+```
+
+```yaml tab="File (YAML)"
+providers:
+  kubernetesCRD:
+    allowCrossNamespace: false
+    # ...
+```
+
+```bash tab="CLI"
+--providers.kubernetescrd.allowCrossNamespace=false
+```
+
+If the parameter is set to `false`, an IngressRoute will not be able to reference any resources
+in another namespace than the IngressRoute namespace.
+
+!!! warning "Deprecation"
+    
+    Please notice that the default value for this option will be set to `false` in a future version.
+
 ## Further
 
 Also see the [full example](../user-guides/crd-acme/index.md) with Let's Encrypt.

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

@@ -540,6 +540,9 @@ TLS key
 `--providers.kubernetescrd`:  
 Enable Kubernetes backend with default settings. (Default: ```false```)
 
+`--providers.kubernetescrd.allowcrossnamespace`:  
+Allow cross namespace resource reference. (Default: ```true```)
+
 `--providers.kubernetescrd.certauthfilepath`:  
 Kubernetes certificate authority file path (not needed for in-cluster client).
 

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

@@ -540,6 +540,9 @@ TLS key
 `TRAEFIK_PROVIDERS_KUBERNETESCRD`:  
 Enable Kubernetes backend with default settings. (Default: ```false```)
 
+`TRAEFIK_PROVIDERS_KUBERNETESCRD_ALLOWCROSSNAMESPACE`:  
+Allow cross namespace resource reference. (Default: ```true```)
+
 `TRAEFIK_PROVIDERS_KUBERNETESCRD_CERTAUTHFILEPATH`:  
 Kubernetes certificate authority file path (not needed for in-cluster client).
 

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

@@ -113,6 +113,7 @@
     certAuthFilePath = "foobar"
     disablePassHostHeaders = true
     namespaces = ["foobar", "foobar"]
+    allowCrossNamespace = true
     labelSelector = "foobar"
     ingressClass = "foobar"
     throttleDuration = 42

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

@@ -123,6 +123,7 @@ providers:
     namespaces:
     - foobar
     - foobar
+    allowCrossNamespace: true
     labelSelector: foobar
     ingressClass: foobar
     throttleDuration: 42s