Enable TCP port 2375 for external connection to Docker

docker-api-port.md

Enable TCP port 2375 for external connection to Docker

See this issue.
Docker best practise to Control and configure Docker with systemd.

1. Create daemon.json file in /etc/docker:

    {"hosts": ["tcp://0.0.0.0:2375", "unix:///var/run/docker.sock"]}
   

2. Add /etc/systemd/system/docker.service.d/override.conf

    [Service]
    ExecStart=
    ExecStart=/usr/bin/dockerd
   

3. Reload the systemd daemon:

    systemctl daemon-reload
   

4. Restart docker:

    systemctl restart docker.service
   

i had to do the following:

$ cat /etc/systemd/system/docker.service.d/override.conf
[Service]
 ExecStart=
 ExecStart=/usr/sbin/dockerd --config-file /etc/docker/daemon.overrided.json

$ cat /etc/docker/daemon.overrided.json
{
  "hosts": ["tcp://0.0.0.0:2375", "unix:///var/run/docker.sock"]
}

The binary is in /usr/sbin/dockerd, and changing the daemon.json conflicted with the default parameter -H fd://