DOCKER_OPTS do not work in config file /etc/default/docker

Question

I have changed /etc/default/docker with DOCKER_OPTS=\"-H tcp://127.0.0.1:2375 -H unix:///var/run/docker.sock\" (docker version 1.4.1 in ubuntu 14.0

Answer 1

According to docker documentation, The recommended way to configure the daemon flags and environment variables for your Docker daemon is to use a systemd drop-in file.

So, for this specific case, do the following:

1. Use the command sudo systemctl edit docker.service to open an override file for docker.service in a text editor.

2. Add or modify the following lines, substituting your own values.

   [Service]
   ExecStart=
   ExecStart=/usr/bin/dockerd -H tcp://127.0.0.1:2375 -H unix:///var/run/docker.sock
   

3. Save the file.

4. Reload the systemctl configuration.

    $ sudo systemctl daemon-reload
   

5. Restart Docker:

    $ sudo systemctl restart docker.service
   

6. Check to see whether the change was honored by reviewing the output of netstat to confirm dockerd is listening on the configured port.

   $ sudo netstat -lntp | grep dockerd
   tcp        0      0 127.0.0.1:2375          0.0.0.0:*               LISTEN      3758/dockerd