how to expose docker api over tcp
## Use the command sudo systemctl edit docker.service
## to open an override file for docker.service in a text editor and
## add below lines(this is for testing purpose only,
##while PROD access or expose Docker api through tls or a proxy)
$ sudo systemctl edit docker.service
[Service]
ExecStart=
#ExecStart=/usr/bin/dockerd -H fd:// -H tcp://127.0.0.1:2375
ExecStart=/usr/bin/dockerd -H fd:// -H tcp://0.0.0.0:2375
#Reload the systemctl configuration.
$ sudo systemctl daemon-reload
#Restart Docker.
$ sudo systemctl restart docker.service
#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
$ sudo docker -H tcp://<your IP>:2375 ps