Publish to random host port while using --network=host

Question

I am trying to access a host URL from within a docker container. I would also like to publish container ports to random ports on the host.

docker run --network=host -P -d somerepo/someimage

However, it looks like the -P and the --net=host options don't want to co-exist as I don't see any port mappings created when I run a docker ports <container_id>

Am I missing something obvious here?

PS: There is no docker-machine involved. Docker engine is running directly on the host machine.

Answer 1

You can't use -P or -p with --net=host because that doesn't make any sense. When you're using --net=host , IF a process in a container opens a port THEN that port is open on your host. No mapping is required, because your container process are running in the host's network environment.