Hi
Did you follow the Docker install instructions from here: Install Docker Engine on CentOS | Docker Docs ?
dockerd should be added to the standard /usr/bin path on CentOS 7. Check to see that it is there (ls /usr/bin/dockerd) - if it is, make sure your path settings are correct. If it’s not, docker hasn’t correctly installed and you might want to try again.
Once you get that figured out, the command you list should expose the remote api. In CentOS 7, the init system is systemd, so you might want to create the following folder/file location with the desired docker exec command:
/etc/systemd/system/docker.service.d/docker.conf
[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H tcp://0.0.0.0:2375 -H unix://var/run/docker.sock
Restart the docker service using systemd commands:
sudo systemctl daemon-reload
sudo systemctl restart docker
You can confirm that the exec took your override parameters by calling:
ps -ef | grep docker
Look for the dockerd process and confirm that your -H settings are listed.
Now, you should be able to hook up to the api: >docker -H :2375 info