docker服务启动错误，Failed to start Docker Application Container Engine.

docker版本19.03.5，配置完阿里云镜像之后
sudo systemctl daemon-reload
sudo systemctl restart docker
失败，我按提示输入命令
systemctl status docker.service -l
得到结果
docker.service - Docker Application Container Engine
Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled)
Active: failed (Result: start-limit) since 一 2020-02-17 20:23:10 CST; 11s ago
Docs: https://docs.docker.com
Process: 15693 ExecStart=/usr/bin/dockerd (code=exited, status=1/FAILURE)
Main PID: 15693 (code=exited, status=1/FAILURE)

2月 17 20:23:08 Master systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
2月 17 20:23:08 Master systemd[1]: Failed to start Docker Application Container Engine.
2月 17 20:23:08 Master systemd[1]: Unit docker.service entered failed state.
2月 17 20:23:08 Master systemd[1]: docker.service failed.
2月 17 20:23:10 Master systemd[1]: docker.service holdoff time over, scheduling restart.
2月 17 20:23:10 Master systemd[1]: Stopped Docker Application Container Engine.
2月 17 20:23:10 Master systemd[1]: start request repeated too quickly for docker.service
2月 17 20:23:10 Master systemd[1]: Failed to start Docker Application Container Engine.
2月 17 20:23:10 Master systemd[1]: Unit docker.service entered failed state.
2月 17 20:23:10 Master systemd[1]: docker.service failed.

到这里没法解决了，我百度很多都没办法。但是一天之后我看到了这一个
http://www.docker.org.cn/thread/72.html
有个大神的解决方法是这样，改掉daemon.json成这样
}
“registry-mirrors”: [“https://xxxxxxx.mirror.aliyuncs.com”],
“storage-driver” : “devicemapper”
}

改完之后我成功启动docker服务
但是！
[wang@localhost ~]$ ps -ef |grep docker
root 16510 1 0 20:32 ? 00:00:00 /usr/bin/dockerd
wang 16718 9138 0 20:35 pts/0 00:00:00 grep --color=auto docker
也就是说阿里云镜像配置可能失败了。

但是我随便下了一个800M的包，下载速度大概1M到4M1秒，好像是正常速度。

其实就算是配置没配上镜像站，也不要紧。因为docker服务只要能启动，运行docker命令有一个-d启动参数，