Linux中的docker报错 Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

Being given a chance to start docker in centos installed in:

Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

 

Solution is as follows:

1. Create the docker group.

   sudo groupadd docker

2. Add the user to the docker group.

   sudo usermod -aG docker $(whoami)

3. Log out and log back in to ensure docker runs with correct permissions.
4. Start docker.

   sudo service docker start