To set the Docker runtime root directory

For the first time playing Docker, the system did not allocate/var partition, and more than 500 g of the remaining space is divided to the/home.
When playing Docker, only to find this goods default storage location is in/var/lib/docker.
There are two solutions: one is to reload the system, which is too impersonal, ignoring ... The next time you deploy the Docker host, you need to be properly partitioned.

The second is to change the Docker default storage path.

Check it out. Manual found:-G,--graph= "/var/lib/docker" set Docker runtime root directory
Using the--graph parameter: Docker--graph=/opt/docker-d automatically generates the/opt/docker directory (0700) and creates Docker related files under that directory

The original mirrors and containers were not found because the path was changed (the original mirror was
In/var/lib/docker/devicemapper/devicemapper/{data,metadata})
Docker configuration files can set most of the background process parameters, the storage location in each operating system is inconsistent
The location in Ubuntu is:/etc/default/docker
The position in the CentOS is:/etc/sysconfig/docker
I use CentOS 7, so I just need to change vim/etc/sysconfig/docker into

Options=--graph= "/home/lib/docker"--selinux-enabled-h fd://

Then the service Docker start restarts the Docker path to/home/lib/docker.