How to use `docker-machine create` so that the docker engine listens on a custom port?

Question

My service provider does not allow me to connect to docker on port 2376. Is there a flag for docker-machine to set up docker on host to listen on another port but 2376 so that commands like

docker-machine ls OR docker-machine env

work? Now they fail because after creation of docker on the host the daemon starts on port 2376 which is not accessible. Sure, I could manually change that port after creation but then the mentioned commands are not aware to connect to the docker daemon on that host on another port but 2376.

Thomasleveil Thomasleveil · Accepted Answer · 2016-01-11T20:17:39

Is there a flag for docker-machine to set up docker on host to listen on another port but 2376

yes, use the -H or --host option of the docker daemon command. To make your Docker daemon listen on port 443 (which should be open all most firewalls), start your docker daemon with:

docker daemon -H tcp://0.0.0.0:443

If your docker host operating system is Debian or Ubuntu, you can set this in the /etc/default/docker file by adding the line DOCKER_OPTS="-H tcp://0.0.0.0:443".

If you are using RedHat or CentOS, add OPTIONS=-H tcp://0.0.0.0:443 to the /etc/sysconfig/docker file.

Using docker-machine

To install a Docker engine with a custom --host option, you would use docker machine with the --engine-opt option:

docker-machine create --engine-opt host=tcp://0.0.0.0:443 ...

Then when you use docker-machine env ... you will note that the DOCKER_HOST environment variable will still be set with the default port 2376, but now you can override it with 443 and it will work.

Unfortunately this won't allow docker-machine ls to work as the 2376 value for the docker engine port is hardcoded in docker-machine drivers. If you really want to get docker-machine ls to work for a different port, the easiest way would be to duplicate one of the docker-machine driver source file that you use and hardcode a different port ; then compile a new docker-machine binary with your new driver.

Let's say the IP address of the remote server is 11.22.33.44.

# create the docker engine using the generic Machine driver
docker-machine create --engine-opt host=tcp://0.0.0.0:443 --driver=generic --generic-ip-address=11.22.33.44 mytestengine

# prepare the environments so that docker client can connect on port 443
docker-machine env mytestengine
export DOCKER_HOST=tcp://11.22.33.44:443

# use docker client as usual
docker version

How to use `docker-machine create` so that the docker engine listens on a custom port?

1 Answers

Using docker-machine