Merge current v2.11 into v3.1

docs/content/providers/docker.md

@@ -20,7 +20,7 @@ This provider works with [Docker (standalone) Engine](https://docs.docker.com/en
 
 ## Configuration Examples
 
-??? example "Configuring Docker & Deploying / Exposing Services"
+??? example "Configuring Docker & Deploying / Exposing one Service"
 
     Enabling the docker provider
 
@@ -73,12 +73,14 @@ When using Docker Compose, labels are specified by the directive
 
 Traefik retrieves the private IP and port of containers from the Docker API.
 
-Port detection works as follows:
+Port detection for private communication works as follows:
 
 - If a container [exposes](https://docs.docker.com/engine/reference/builder/#expose) a single port,
-  then Traefik uses this port for private communication.
+  then Traefik uses this port.
 - If a container [exposes](https://docs.docker.com/engine/reference/builder/#expose) multiple ports,
-  or does not expose any port, then you must manually specify which port Traefik should use for communication
+  then Traefik uses the lowest port.  E.g. if `80` and `8080` are exposed, Traefik will use `80`.
+- If a container does not expose any port, or the selection from multiple ports does not fit,
+  then you must manually specify which port Traefik should use for communication
   by using the label `traefik.http.services.<service_name>.loadbalancer.server.port`
   (Read more on this label in the dedicated section in [routing](../routing/providers/docker.md#services)).
 
@@ -586,7 +588,7 @@ providers:
 _Optional, Default=false_
 
 If the parameter is set to `true`,
-any [servers load balancer](../routing/services/index.md#servers-load-balancer) defined for Docker containers is created 
+any [servers load balancer](../routing/services/index.md#servers-load-balancer) defined for Docker containers is created
 regardless of the [healthiness](https://docs.docker.com/engine/reference/builder/#healthcheck) of the corresponding containers.
 It also then stays alive and responsive even at times when it becomes empty,
 i.e. when all its children containers become unhealthy.

docs/content/providers/swarm.md

@@ -20,7 +20,7 @@ This provider works with [Docker Swarm Mode](https://docs.docker.com/engine/swar
 
 ## Configuration Examples
 
-??? example "Configuring Docker Swarm & Deploying / Exposing Services"
+??? example "Configuring Docker Swarm & Deploying / Exposing one Service"
 
     Enabling the Swarm provider
 
@@ -48,7 +48,9 @@ This provider works with [Docker Swarm Mode](https://docs.docker.com/engine/swar
     --providers.swarm.endpoint=tcp://127.0.0.1:2377
     ```
 
-    Attach labels to services (not to containers) while in Swarm mode (in your docker compose file)
+    Attach labels to a single service (not containers) while in Swarm mode (in your Docker compose file).
+    When there is only one service, and the router does not specify a service,
+    then that service is automatically assigned to the router.
 
     ```yaml
     version: "3"