Step 1 - Create a file at /etc/systemd/system/docker.service.d/startup_options.conf with the below contents:

# /etc/systemd/system/docker.service.d/override.conf
[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H fd:// -H tcp://0.0.0.0:2376

• -H tcp:0.0.0.0:2376 makes the Docker API available for all external IP addresses on port 2376. This is the port number you have to provide in section Docker Credentials of the sensor settings.

• -H fd:// makes the API locally available to get the Docker commands to work on the console.

Note: The -H flag binds dockerd to a listening socket, either a Unix socket or a TCP port. You can specify multiple -H flags to bind to multiple sockets/ports. The default -H fd:// uses systemd's socket activation feature to refer to /lib/systemd/system/docker.socket.

Step 2 - Reload the unit files:

$ sudo systemctl daemon-reload

Step 3 - Restart the docker daemon with new startup options: $ sudo systemctl restart docker.service

Step 4 - Ensure that anyone that has access to the TCP listening socket is a trusted user since access to the docker daemon is root-equivalent.

Step 5 - Set a Docker Client of another machine.

export DOCKER_HOST="tcp://192.168.99.100:2376"