Make Docker for mac listen on a tcp port

Question

I'm trying to get docker-java (https://github.com/docker-java/docker-java) to work with Docker for mac (https://docs.docker.com/docker-for-mac/).

How can I set the equivalent of:

DOCKER_OPTS="-H tcp://127.0.0.1:2375 -H unix:///var/run/docker.sock"

On the mac version of Docker?

Answer 1

There is a related answer which suggests a workaround using socat.

It does indeed work to expose port 2375 on the network:

socat TCP-LISTEN:2375,reuseaddr,fork UNIX-CONNECT:/var/run/docker.sock

Reference: Access Docker daemon Remote api on Docker for Mac

Answer 2

If you are using the last docker for mac beta, according to issue 25064:

~/Library/Containers/com.docker.docker/Data/database/com.docker.driver.amd64-linux is a git database.

Note: if ~/Library/Containers/com.docker.docker/Data/database/ does not contain com.docker.driver.amd64-linux, go to that database/ folder, and do a git reset --hard.

The daemon configuration is under etc/docker/daemon.json, which just uses the config from the Linux configuration file.

You need to change the config and then do a git commit: docker should restart automatically at that point (if not, restart it) with the new configuration.

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As mentioned by the OP Michael Nelson in the comments, and detailed in "Docker for Windows" (which has sections relevant for "Docker for Mac")

The VM (Alpine-based) uses OpenRC as its init system.

The Docker init script relies on a /usr/bin/mobyconfig script.
This mobyconfig script requires the kernel to boot with a com.docker.database label specifying the location of the config file or it bails.

The mobyconfig script is able to retrieve network and insecure-registry configuration for the Docker daemon or pick up a config file from /etc/docker/daemon.json.