How do i expose the Docker Remote API on Centos 7?

docker centos7 docker-api
user3412172 picture user3412172 · Oct 25, 2016 · Viewed 11k times · Source

On ubuntu i can go into /etc/init/docker.conf and put in DOCKER_OPTS='-H tcp://0.0.0.0:4243 -H unix:///var/run/docker.sock' to get the json data to display on my browser but how can i do it for Centos?

I have tried creating a file in /etc/sysconfig/docker and placing other_args="-H tcp://0.0.0.0:4243 -H unix:///var/run/docker.sock" inside the file and restarting docker but it doesn't do anything.

Answer

larsks picture larsks · Oct 25, 2016

The systemd unit installed by the Docker corp package hardcodes the command line used to start the docker daemon:

[Service]
Type=notify
ExecStart=/usr/bin/dockerd
ExecReload=/bin/kill -s HUP $MAINPID
[...]

There is no support for reading a file from /etc/sysconfig or elsewhere to modify the command line. Fortunately, systemd gives us the tools we need to change this behavior.

The simplest solution is probably to create the file /etc/systemd/system/docker.service.d/docker-external.conf (the exact filename doesn't matter; it just needs to end with .conf) with the following contents:

[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0:4243 -H unix:///var/run/docker.sock

And then:

systemctl daemon-reload
systemctl restart docker

This is actually documented on the Docker website in this document, which includes instructions for a more flexible solution that will allow you to use files in /etc/sysconfig to control the daemon.

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