New Routing Reference Documentation

docs/content/reference/routing-configuration/kubernetes/crd/http/middleware.md

@@ -0,0 +1,53 @@
+---
+title: "Traefik Kubernetes Middleware Documentation"
+description: "Learn how to configure a Traefik Proxy Kubernetes Middleware to reach Services, which handle incoming requests. Read the technical documentation."
+---
+
+`Middleware` is the CRD implementation of a [Traefik middleware](../../../http/middlewares/overview.md).
+
+Before creating `Middleware` objects, you need to apply the [Traefik Kubernetes CRDs](https://doc.traefik.io/traefik/reference/dynamic-configuration/kubernetes-crd/#definitions) to your Kubernetes cluster.
+
+This registers the `Middleware` kind and other Traefik-specific resources.
+
+!!! tip "Cross-provider namespace"
+    As Kubernetes also has its own notion of namespace, one should not confuse the Kubernetes namespace of a resource (in the reference to the middleware) with the [provider namespace](../../../../install-configuration/providers/overview.md#provider-namespace), when the definition of the middleware comes from another provider. In this context, specifying a namespace when referring to the resource does not make any sense, and will be ignored. Additionally, when you want to reference a Middleware from the CRD Provider, you have to append the namespace of the resource in the resource-name as Traefik appends the namespace internally automatically.
+
+!!! note "Cross-Namespace References"
+    In the example below, the middleware is defined in the `foo` namespace while being referenced from an IngressRoute in another namespace. To enable such cross-namespace references, the `allowCrossNamespace` option must be enabled in the Traefik [Kubernetes CRD provider](../../../../install-configuration/providers/kubernetes/kubernetes-crd.md#configuration-options) configuration. If you prefer to avoid this requirement, you can define and reference the Middleware within the same namespace.
+
+## Configuration Example
+
+```yaml tab="Middleware"
+apiVersion: traefik.io/v1alpha1
+kind: Middleware
+metadata:
+  name: stripprefix
+  namespace: foo
+
+spec:
+  stripPrefix:
+    prefixes:
+      - /stripit
+```
+
+```yaml tab="IngressRoute"
+apiVersion: traefik.io/v1alpha1
+kind: IngressRoute
+metadata:
+  name: ingressroutebar
+
+spec:
+  entryPoints:
+    - web
+  routes:
+  - match: Host(`example.com`) && PathPrefix(`/stripit`)
+    kind: Rule
+    services:
+    - name: whoami
+      port: 80
+    middlewares:
+    - name: stripprefix
+      namespace: foo
+```
+
+For more information about the available middlewares, navigate to the dedicated [middlewares overview section](../../../http/middlewares/overview.md).