Improve migration guide

Co-authored-by: Baptiste Mayelle <baptiste.mayelle@traefik.io>

docs/content/deprecation/features.md

@@ -4,20 +4,23 @@ This page is maintained and updated periodically to reflect our roadmap and any
 
 | Feature                                                                                                              | Deprecated | End of Support | Removal |
 |----------------------------------------------------------------------------------------------------------------------|------------|----------------|---------|
-| [Kubernetes CRDs API Version `traefik.io/v1alpha1`](#kubernetes-crds-api-version-traefikiov1alpha1)                  | 3.0        | N/A            | 4.0     |
+| [Kubernetes CRD Provider API Version `traefik.io/v1alpha1`](#kubernetes-crd-provider-api-version-traefikiov1alpha1)  | 3.0        | N/A            | 4.0     |
 | [Kubernetes Ingress API Version `networking.k8s.io/v1beta1`](#kubernetes-ingress-api-version-networkingk8siov1beta1) | N/A        | N/A            | 3.0     |
 | [CRD API Version `apiextensions.k8s.io/v1beta1`](#kubernetes-ingress-api-version-networkingk8siov1beta1)             | N/A        | N/A            | 3.0     |
 
 ## Impact
 
-### Kubernetes CRDs API Version `traefik.io/v1alpha1`
+### Kubernetes CRD Provider API Version `traefik.io/v1alpha1`
 
-The Kubernetes CRD provider API Version `traefik.io/v1alpha1` will subsequently be deprecated in Traefik v3. The next version will be `traefik.io/v1`.
+The Kubernetes CRD provider API Version `traefik.io/v1alpha1` is deprecated in Traefik v3.
+Please use the API Group `traefik.io/v1` instead.
 
 ### Kubernetes Ingress API Version `networking.k8s.io/v1beta1`
 
-The Kubernetes Ingress API Version `networking.k8s.io/v1beta1` is removed in v3. Please use the API Group `networking.k8s.io/v1` instead.
+The Kubernetes Ingress API Version `networking.k8s.io/v1beta1` support is removed in v3. 
+Please use the API Group `networking.k8s.io/v1` instead.
 
-### Traefik CRD API Version `apiextensions.k8s.io/v1beta1`
+### Traefik CRD Definitions API Version `apiextensions.k8s.io/v1beta1`
 
-The Traefik CRD API Version `apiextensions.k8s.io/v1beta1` is removed in v3. Please use the API Group `apiextensions.k8s.io/v1` instead.
+The Traefik CRD definitions API Version `apiextensions.k8s.io/v1beta1` support is removed in v3.
+Please use the API Group `apiextensions.k8s.io/v1` instead.

docs/content/migration/v2-to-v3.md

@@ -10,28 +10,335 @@ How to Migrate from Traefik v2 to Traefik v3.
 
 The version 3 of Traefik introduces a number of breaking changes,
 which require one to update their configuration when they migrate from v2 to v3.
-The goal of this page is to recapitulate all of these changes, and in particular to give examples,
+The goal of this page is to recapitulate all of these changes,
-feature by feature, of how the configuration looked like in v2, and how it now looks like in v3.
+and in particular to give examples, feature by feature, 
+of how the configuration looked like in v2,
+and how it now looks like in v3.
 
-## IPWhiteList
+## Static configuration
+
+### Docker & Docker Swarm
+
+In v3, the provider Docker has been split into 2 providers:
+
+- Docker provider (without Swarm support)
+- Swarm provider  (Swarm support only)
+
+??? example "An example usage of v2 Docker provider with Swarm"
+
+    ```yaml tab="File (YAML)"
+    providers:
+      docker:
+        swarmMode: true
+    ```
+
+    ```toml tab="File (TOML)"
+    [providers.docker]
+        swarmMode=true
+    ```
+
+    ```bash tab="CLI"
+    --providers.docker.swarmMode=true
+    ```
+
+This configuration is now unsupported and would prevent Traefik to start.
+
+#### Remediation
+
+In v3, the `swarmMode` should not be used with the Docker provider, and, to use Swarm, the Swarm provider should be used instead.
+
+??? example "An example usage of the Swarm provider"
+
+    ```yaml tab="File (YAML)"
+    providers:
+      swarm:
+        endpoint: "tcp://127.0.0.1:2377"
+    ```
+
+    ```toml tab="File (TOML)"
+    [providers.swarm]
+        endpoint="tcp://127.0.0.1:2377"
+    ```
+
+    ```bash tab="CLI"
+    --providers.swarm.endpoint=tcp://127.0.0.1:2377
+    ```
+
+### HTTP3 Experimental Configuration
+
+In v3, HTTP/3 is no longer an experimental feature.
+It can be enabled on entry points without the associated `experimental.http3` option, which is now removed.
+It is now unsupported and would prevent Traefik to start.
+
+??? example "An example usage of v2 Experimental `http3` option"
+
+    ```yaml tab="File (YAML)"
+    experimental:
+      http3: true
+    ```
+
+    ```toml tab="File (TOML)"
+    [experimental]
+        http3=true
+    ```
+
+    ```bash tab="CLI"
+    --experimental.http3=true
+    ```
+
+#### Remediation
+
+The `http3` option should be removed from the static configuration experimental section.
+
+### Consul provider
+
+The Consul provider `namespace` option was deprecated in v2 and is now removed in v3.
+It is now unsupported and would prevent Traefik to start.
+
+??? example "An example usage of v2 Consul `namespace` option"
+
+    ```yaml tab="File (YAML)"
+    consul:
+      namespace: foobar
+    ```
+
+    ```toml tab="File (TOML)"
+    [consul]
+        namespace=foobar
+    ```
+
+    ```bash tab="CLI"
+    --consul.namespace=foobar
+    ```
+
+#### Remediation
+
+In v3, the `namespaces` option should be used instead of the `namespace` option.
+
+??? example "An example usage of Consul `namespaces` option"
+
+    ```yaml tab="File (YAML)"
+    consul:
+      namespaces:
+        - foobar
+    ```
+
+    ```toml tab="File (TOML)"
+    [consul]
+        namespaces=["foobar"]
+    ```
+
+    ```bash tab="CLI"
+    --consul.namespaces=foobar
+    ```
+
+### ConsulCatalog provider
+
+The ConsulCatalog provider `namespace` option was deprecated in v2 and is now removed in v3.
+It is now unsupported and would prevent Traefik to start.
+
+??? example "An example usage of v2 ConsulCatalog `namespace` option"
+
+    ```yaml tab="File (YAML)"
+    consulCatalog:
+      namespace: foobar
+    ```
+
+    ```toml tab="File (TOML)"
+    [consulCatalog]
+        namespace=foobar
+    ```
+
+    ```bash tab="CLI"
+    --consulCatalog.namespace=foobar
+    ```
+
+#### Remediation
+
+In v3, the `namespaces` option should be used instead of the `namespace` option.
+
+??? example "An example usage of ConsulCatalog `namespaces` option"
+
+    ```yaml tab="File (YAML)"
+    consulCatalog:
+      namespaces:
+        - foobar
+    ```
+
+    ```toml tab="File (TOML)"
+    [consulCatalog]
+        namespaces=["foobar"]
+    ```
+
+    ```bash tab="CLI"
+    --consulCatalog.namespaces=foobar
+    ```
+
+### Nomad provider
+
+The Nomad provider `namespace` option was deprecated in v2 and is now removed in v3.
+It is now unsupported and would prevent Traefik to start.
+
+??? example "An example usage of v2 Nomad `namespace` option"
+
+    ```yaml tab="File (YAML)"
+    nomad:
+      namespace: foobar
+    ```
+
+    ```toml tab="File (TOML)"
+    [nomad]
+        namespace=foobar
+    ```
+
+    ```bash tab="CLI"
+    --nomad.namespace=foobar
+    ```
+
+#### Remediation
+
+In v3, the `namespaces` option should be used instead of the `namespace` option.
+
+??? example "An example usage of Nomad `namespaces` option"
+
+    ```yaml tab="File (YAML)"
+    nomad:
+      namespaces:
+        - foobar
+    ```
+
+    ```toml tab="File (TOML)"
+    [nomad]
+        namespaces=["foobar"]
+    ```
+
+    ```bash tab="CLI"
+    --nomad.namespaces=foobar
+    ```
+
+### Rancher v1 Provider
+
+In v3, the Rancher v1 provider has been removed because Rancher v1 is [no longer actively maintaned](https://rancher.com/docs/os/v1.x/en/support/),
+and Rancher v2 is supported as a standard Kubernetes provider.
+
+??? example "An example of Traefik v2 Rancher v1 configuration"
+
+    ```yaml tab="File (YAML)"
+    providers:
+      rancher: {}
+    ```
+
+    ```toml tab="File (TOML)"
+    [providers.rancher]
+    ```
+
+    ```bash tab="CLI"
+    --providers.rancher=true
+    ```
+
+This configuration is now unsupported and would prevent Traefik to start.
+
+#### Remediation
+
+Rancher 2.x requires Kubernetes and does not have a metadata endpoint of its own for Traefik to query.
+As such, Rancher 2.x users should utilize the [Kubernetes CRD provider](../providers/kubernetes-crd.md) directly.
+
+Also, all Rancher provider related configuration should be removed from the static configuration.
+
+### Marathon provider
+
+Marathon maintenance [ended on October 31, 2021](https://github.com/mesosphere/marathon/blob/master/README.md).
+In v3, the Marathon provider has been removed.
+
+??? example "An example of v2 Marathon provider configuration"
+
+    ```yaml tab="File (YAML)"
+    providers:
+      marathon: {}
+    ```
+
+    ```toml tab="File (TOML)"
+    [providers.marathon]
+    ```
+
+    ```bash tab="CLI"
+    --providers.marathon=true
+    ```
+
+This configuration is now unsupported and would prevent Traefik to start.
+
+#### Remediation
+
+All Marathon provider related configuration should be removed from the static configuration.
+
+### InfluxDB v1
+
+InfluxDB v1.x maintenance [ended in 2021](https://www.influxdata.com/blog/influxdb-oss-and-enterprise-roadmap-update-from-influxdays-emea/).
+In v3, the InfluxDB v1 metrics provider has been removed.
+
+??? example "An example of Traefik v2 InfluxDB v1 metrics configuration"
+
+    ```yaml tab="File (YAML)"
+    metrics:
+      influxDB: {}
+    ```
+
+    ```toml tab="File (TOML)"
+    [metrics.influxDB]
+    ```
+
+    ```bash tab="CLI"
+    --metrics.influxDB=true
+    ```
+
+This configuration is now unsupported and would prevent Traefik to start.
+
+#### Remediation
+
+All InfluxDB v1 metrics provider related configuration should be removed from the static configuration.
+
+### Pilot
+
+Traefik Pilot is no longer available since October 4th, 2022.
+
+??? example "An example of v2 Pilot configuration"
+
+    ```yaml tab="File (YAML)"
+    pilot:
+      token: foobar
+    ```
+
+    ```toml tab="File (TOML)"
+    [pilot]
+        token=foobar
+    ```
+
+    ```bash tab="CLI"
+    --pilot.token=foobar
+    ```
+
+In v2, Pilot configuration was deprecated and ineffective,
+it is now unsupported and would prevent Traefik to start.
+
+#### Remediation
+
+All Pilot related configuration should be removed from the static configuration.
+
+## Dynamic configuration
+
+### IPWhiteList
 
 In v3, we renamed the `IPWhiteList` middleware to `IPAllowList` without changing anything to the configuration. 
 
-## gRPC Metrics
+### Deprecated Options Removal
 
-In v3, the reported status code for gRPC requests is now the value of the `Grpc-Status` header.  
-
-## Deprecated Options Removal
-
-- The `pilot` option has been removed from the static configuration.
 - The `tracing.datadog.globaltag` option has been removed.
-- The `namespace` option of Consul, Consul Catalog and Nomad providers has been removed.
 - The `tls.caOptional` option has been removed from the ForwardAuth middleware, as well as from the HTTP, Consul, Etcd, Redis, ZooKeeper, Consul Catalog, and Docker providers.
 - `sslRedirect`, `sslTemporaryRedirect`, `sslHost`, `sslForceHost` and `featurePolicy` options of the Headers middleware have been removed.
 - The `forceSlash` option of the StripPrefix middleware has been removed.
 - The `preferServerCipherSuites` option has been removed.
 
-## Matchers
+### Matchers
 
 In v3, the `Headers` and `HeadersRegexp` matchers have been renamed to `Header` and `HeaderRegexp` respectively.
 
@@ -48,61 +355,42 @@ and should be explicitly combined using logical operators to mimic previous beha
 
 `HostHeader` has been removed, use `Host` instead.
 
-## Content-Type Auto-Detection
-
-In v3, the `Content-Type` header is not auto-detected anymore when it is not set by the backend.
-One should use the `ContentType` middleware to enable the `Content-Type` header value auto-detection.
-
-## HTTP/3
-
-In v3, HTTP/3 is no longer an experimental feature.
-The `experimental.http3` option has been removed from the static configuration.
-
-## TCP ServersTransport
-
-In v3, the support of `TCPServersTransport` has been introduced.
-When using the KubernetesCRD provider, it is therefore necessary to update [RBAC](../reference/dynamic-configuration/kubernetes-crd.md#rbac) and [CRD](../reference/dynamic-configuration/kubernetes-crd.md) manifests.
-
 ### TCP LoadBalancer `terminationDelay` option
 
 The TCP LoadBalancer `terminationDelay` option has been removed.
 This option can now be configured directly on the `TCPServersTransport` level, please take a look at this [documentation](../routing/services/index.md#terminationdelay)
 
-## Rancher v1
+### Kubernetes CRDs API Group `traefik.containo.us`
-
-In v3, the rancher v1 provider has been removed because Rancher v1 is [no longer actively maintaned](https://rancher.com/docs/os/v1.x/en/support/) and v2 is supported as a standard Kubernetes provider.
-
-Rancher 2.x requires Kubernetes and does not have a metadata endpoint of its own for Traefik to query.
-As such, Rancher 2.x users should utilize the [Kubernetes CRD provider](../providers/kubernetes-crd.md) directly.
-
-## Marathon provider
-
-In v3, the Marathon provider has been removed.
-
-## InfluxDB v1
-
-In v3, the InfluxDB v1 metrics provider has been removed because InfluxDB v1.x maintenance [ended in 2021](https://www.influxdata.com/blog/influxdb-oss-and-enterprise-roadmap-update-from-influxdays-emea/).
-
-## Kubernetes CRDs API Group `traefik.containo.us`
 
 In v3, the Kubernetes CRDs API Group `traefik.containo.us` has been removed. 
 Please use the API Group `traefik.io` instead.
 
-## Docker & Docker Swarm
+### Kubernetes Ingress API Group `networking.k8s.io/v1beta1`
-
-In v3, the provider Docker has been split into 2 providers:
-
-- Docker provider (without Swarm support)
-- Swarm provider  (Swarm support only)
-
-## Kubernetes Ingress API Group `networking.k8s.io/v1beta1`
 
 In v3, the Kubernetes Ingress API Group `networking.k8s.io/v1beta1` ([removed since Kubernetes v1.22](https://kubernetes.io/docs/reference/using-api/deprecation-guide/#ingress-v122)) support has been removed.
 
 Please use the API Group `networking.k8s.io/v1` instead.
 
-## Traefik CRD API Version `apiextensions.k8s.io/v1beta1`
+### Traefik CRD API Version `apiextensions.k8s.io/v1beta1`
 
 In v3, the Traefik CRD API Version `apiextensions.k8s.io/v1beta1` ([removed since Kubernetes v1.22](https://kubernetes.io/docs/reference/using-api/deprecation-guide/#customresourcedefinition-v122)) support has been removed.
 
 Please use the CRD definition with the API Version `apiextensions.k8s.io/v1` instead.
+
+## Operations
+
+### Traefik RBAC Update
+
+In v3, the support of `TCPServersTransport` has been introduced.
+When using the KubernetesCRD provider, it is therefore necessary to update [RBAC](../reference/dynamic-configuration/kubernetes-crd.md#rbac) and [CRD](../reference/dynamic-configuration/kubernetes-crd.md) manifests.
+
+### Content-Type Auto-Detection
+
+In v3, the `Content-Type` header is not auto-detected anymore when it is not set by the backend.
+One should use the `ContentType` middleware to enable the `Content-Type` header value auto-detection.
+
+### Observability
+
+#### gRPC Metrics
+
+In v3, the reported status code for gRPC requests is now the value of the `Grpc-Status` header.  

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

@@ -201,9 +201,6 @@ WriteTimeout is the maximum duration before timing out writes of the response. I
 `--entrypoints.<name>.udp.timeout`:  
 Timeout defines how long to wait on an idle session before releasing the related resources. (Default: ```3```)
 
-`--experimental.http3`:  
-Enable HTTP3. (Default: ```false```)
-
 `--experimental.kubernetesgateway`:  
 Allow the Kubernetes gateway api provider usage. (Default: ```false```)
 

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

@@ -201,9 +201,6 @@ WriteTimeout is the maximum duration before timing out writes of the response. I
 `TRAEFIK_ENTRYPOINTS_<NAME>_UDP_TIMEOUT`:  
 Timeout defines how long to wait on an idle session before releasing the related resources. (Default: ```3```)
 
-`TRAEFIK_EXPERIMENTAL_HTTP3`:  
-Enable HTTP3. (Default: ```false```)
-
 `TRAEFIK_EXPERIMENTAL_KUBERNETESGATEWAY`:  
 Allow the Kubernetes gateway api provider usage. (Default: ```false```)
 

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

@@ -459,7 +459,6 @@
 
 [experimental]
   kubernetesGateway = true
-  http3 = true
   [experimental.plugins]
     [experimental.plugins.Descriptor0]
       moduleName = "foobar"

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

@@ -489,7 +489,6 @@ certificatesResolvers:
     tailscale: {}
 experimental:
   kubernetesGateway: true
-  http3: true
   plugins:
     Descriptor0:
       moduleName: foobar

pkg/config/static/experimental.go

@@ -8,5 +8,4 @@ type Experimental struct {
 	LocalPlugins map[string]plugins.LocalDescriptor `description:"Local plugins configuration." json:"localPlugins,omitempty" toml:"localPlugins,omitempty" yaml:"localPlugins,omitempty" export:"true"`
 
 	KubernetesGateway bool `description:"Allow the Kubernetes gateway api provider usage." json:"kubernetesGateway,omitempty" toml:"kubernetesGateway,omitempty" yaml:"kubernetesGateway,omitempty" export:"true"`
-	HTTP3             bool `description:"Enable HTTP3." json:"http3,omitempty" toml:"http3,omitempty" yaml:"http3,omitempty" export:"true"`
 }