报错信息如下：
[root@localhost localdisk]# systemctl restart docker
Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.
[root@localhost localdisk]# systemctl status docker
docker.service - Docker Application Container Engine
Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since 日 2019-05-19 17:15:19 CST; 6s ago
Docs: http://docs.docker.com
Process: 13393 ExecStart=/usr/bin/dockerd-current --add-runtime docker-runc=/usr/libexec/docker/docker-runc-current --default-runtime=docker-runc --exec-opt native.cgroupdriver=systemd --userland-proxy-path=/usr/libexec/docker/docker-proxy-current --init-path=/usr/libexec/docker/docker-init-current --seccomp-profile=/etc/docker/seccomp.json --graph=/localdisk/docker --storage-driver=overlay --registry-mirror=https://docker.mirrors.ustc.edu.cn $OPTIONS $DOCKER_STORAGE_OPTIONS $DOCKER_NETWORK_OPTIONS $ADD_REGISTRY $BLOCK_REGISTRY $INSECURE_REGISTRY $REGISTRIES (code=exited, status=1/FAILURE)
Main PID: 13393 (code=exited, status=1/FAILURE)
5月 19 17:15:19 localhost.localdomain systemd[1]: Starting Docker Application Container Engine...
5月 19 17:15:19 localhost.localdomain dockerd-current[13393]: unable to configure the Docker daemon with file /etc/docker/daemon.json: the following direc...edu.cn])
5月 19 17:15:19 localhost.localdomain systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
5月 19 17:15:19 localhost.localdomain systemd[1]: Failed to start Docker Application Container Engine.
5月 19 17:15:19 localhost.localdomain systemd[1]: Unit docker.service entered failed state.
5月 19 17:15:19 localhost.localdomain systemd[1]: docker.service failed.
Hint: Some lines were ellipsized, use -l to show in full.
解决方法：
1.防火墙和selinux都关了
2.修改/etc/docker/daemon.json这个文件（就这样粘贴复制，别多逗号）
{
"registry-mirrors": ["https://docker.mirrors.ustc.edu.cn"]
}
3.重启docker，在不行重启虚拟机
systemctl daemon-reload
systemctl restart docker
效果如下：
