Merge pull request #9678 from xcffl/doc-sock-in-container-privileged

[CI:DOCS] Add docs about how to access APIs inside containers

docs/source/markdown/podman-system-service.1.md

@@ -13,6 +13,10 @@ If no endpoint is provided, defaults will be used.  The default endpoint for a r
 service is *unix:/run/podman/podman.sock* and rootless is *unix:/$XDG_RUNTIME_DIR/podman/podman.sock* (for
 example *unix:/run/user/1000/podman/podman.sock*)
 
+To access the API service inside a container:
+- mount the socket as a volume
+- run the container with `--security-opt label:disable`
+
 The REST API provided by **podman system service** is split into two parts: a compatibility layer offering support for the Docker v1.40 API, and a Podman-native Libpod layer.
 Documentation for the latter is available at *https://docs.podman.io/en/latest/_static/api.html*.
 Both APIs are versioned, but the server will not reject requests with an unsupported version set.