systemctl start docker失败原因

背景：

使用自配置文件 /etc/docker/daemon.json

systemctl enable docker.service将docker加入服务

 

问题：

dockerd可以正常启动，但是systemctl start docker.service报错，如图：

Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.

使用journalctl -xe查看具体原因：

1月 24 08:19:15 vultr.guest systemd[1]: Starting Docker Application Container Engine...
-- Subject: Unit docker.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker.service has begun starting up.
1月 24 08:19:15 vultr.guest dockerd[3471]: unable to configure the Docker daemon with file /etc/docker/daemon.json: the following directives are specified both as a flag and in the
1月 24 08:19:15 vultr.guest systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
1月 24 08:19:15 vultr.guest systemd[1]: Failed to start Docker Application Container Engine.
-- Subject: Unit docker.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker.service has failed.
--
-- The result is failed.
1月 24 08:19:15 vultr.guest systemd[1]: Unit docker.service entered failed state.
1月 24 08:19:15 vultr.guest systemd[1]: docker.service failed.
1月 24 08:19:17 vultr.guest systemd[1]: docker.service holdoff time over, scheduling restart.
1月 24 08:19:17 vultr.guest systemd[1]: Stopped Docker Application Container Engine.
-- Subject: Unit docker.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker.service has finished shutting down.
1月 24 08:19:17 vultr.guest systemd[1]: Starting Docker Application Container Engine...
-- Subject: Unit docker.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker.service has begun starting up.
1月 24 08:19:17 vultr.guest dockerd[3475]: unable to configure the Docker daemon with file /etc/docker/daemon.json: the following directives are specified both as a flag and in the
1月 24 08:19:17 vultr.guest systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
1月 24 08:19:17 vultr.guest systemd[1]: Failed to start Docker Application Container Engine.
-- Subject: Unit docker.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit docker.service has failed.

 

实际上，上述最重要的是

unable to configure the Docker daemon with file /etc/docker/daemon.json: the following directives are specified both as a flag and in the

搜官网（https://docs.docker.com/config/daemon/），可以知道，是由于自配置的deamon.json和自动启动参数冲突。由于是systemctl启动，因此查看 /usr/lib/systemd/system/docker.service中的ExecStart项，发现其后面多了一句 -H unix:/，而我们的daemon.json指定了host。因此冲突。

 

将其删除即可。

 

systemctl daemon-reload

systemctl start docker.service

问题解决。