If you have been using docker for a while you may have noticed that some containers requires bind mounting /var/run/docker.sock.
Or ever wondered why when docker engine/daemon is off, you get the next message when running :
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
So what does it mean?
The docker.sock is a Unix socket and this is basically how processes in Unix can communicate with each other to share some data.
In case of docker