docker.service启动报错的一次排查详解（docker.service 不存在）

执行以下命令报错

systemctl restart docker

查看错误信息

systemctl status docker -l

报错信息如下：

● docker.service - Docker Application Container Engine Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled) Drop-In: /etc/systemd/system/docker.service.d └─kolla.conf Active: failed (Result: exit-code) since 三 2018-08-01 16:32:27 CST; 52min ago Docs: https://docs.docker.com Process: 3833722 ExecStart=/usr/bin/docker daemon --insecure-registry 172.16.59.153 (code=exited, status=1/FAILURE) Main PID: 3833722 (code=exited, status=1/FAILURE) Memory: 8.0K CGroup: /system.slice/docker.service 8月 01 16:32:26 czwei004 systemd[1]: Starting Docker Application Container Engine... 8月 01 16:32:26 czwei004 docker[3833722]: time="2018-08-01T16:32:26.527063936+08:00" level=info msg="libcontainerd: new containerd process, pid: 3833733" 8月 01 16:32:27 czwei004 docker[3833722]: time="2018-08-01T16:32:27.532317497+08:00" level=warning msg="devmapper: Usage of loopback devices is strongly discouraged for production use. Please use `--storage-opt dm.thinpooldev` or use `man docker` to refer to dm.thinpooldev section." 8月 01 16:32:27 czwei004 docker[3833722]: time="2018-08-01T16:32:27.560010414+08:00" level=warning msg="devmapper: Base device already exists and has filesystem xfs on it. User specified filesystem will be ignored." 8月 01 16:32:27 czwei004 docker[3833722]: time="2018-08-01T16:32:27.577758251+08:00" level=fatal msg="Error starting daemon: error initializing graphdriver: \"/var/lib/docker\" contains several valid graphdrivers: devicemapper, overlay2; Please cleanup or explicitly choose storage driver (-s )" 8月 01 16:32:27 czwei004 systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE 8月 01 16:32:27 czwei004 systemd[1]: Failed to start Docker Application Container Engine. 8月 01 16:32:27 czwei004 systemd[1]: Unit docker.service entered failed state. 8月 01 16:32:27 czwei004 systemd[1]: docker.service failed.

注意到以上错误信息中

msg="Error starting daemon: error initializing graphdriver: \"/var/lib/docker\" contains several valid graphdrivers: devicemapper, overlay2; Please cleanup or explicitly choose storage driver (-s )"

到docker目录下查看，有devicemapper的目录和overlay2的目录

原因是我之前装了高版本的docker-engine，默认的存储驱动是overlay2，卸载的时候docker目录下残留了overlay2的文件夹，后来安装了低版本的docker，默认的又是devicemapper，于是就有了多个存储驱动

重启机器后删除overlay2的目录后可以启动。

补充知识：CentOS7修改Docker镜像默认存储位置

停止docker服务

# systemctl stop docker

修改docker服务启动文件

# vim /etc/sysconfig/docker OPTIONS='--selinux-enabled --log-driver=journald --graph=/docker --signature-verification=false --insecure-registry 192.168.1.1' #--insecure-registry 192.168.1.1这是仓库地址可以忽略 # /docker这个目录就是我用于替代默认/var/lib/docker的目录，目录创建好之后记得“mv /var/lib/docker/* /docker/”，把所有原

先目录下所有的文件和目录拷贝到新目录下。

重新加载配置并启动

# systemctl daemon-reload # systemctl start docker

检查docker信息

# docker info