Dock worker startup error reported as:
[root@iz8vb4rhbik3h93v48ztfvz dockworker]# systemctl restart dockworker. Service
docker job. The service failed because the control process exited with an error code. See “systemctl state docker”. Services” and “journalctl -xe” for more information.
[root@iz8vb4rhbik3h93v48ztfvz docker]# systemctl stop docker
[root@iz8vb4rhbik3h93v48ztfvz docker]# systemctl status docker
● docker load:load(/usr/lib/systemd/system/ Docker .service; enable;
Activation:failed(result:startup limit) from Mon 2020-06-15 23:52:04 CST;
Docs: https://docs.docker.com>
Process: 9466 ExecStart=/usr/bin/dockerd -H fd://–containerd=/run/containerd/containerd. sock (code=exit, status=1/FAILURE)
Main PID: 9466 (code=exit, status=1/FAILURE)</p

Jun 15 23:52:02 iz8vb4rhbik3h93v48ztfvz systemd[1]: unit docker application container engine failed to start.
Jun 15 23:52:02 iz8vb4rhbik3h93v48ztfvz systemd[1]: Unit docker service enters failed state.
Jun 15 23:52:02 iz8vb4rhbik3h93v48ztfvz systemd[1]: docker service failed.
Jun 15 23:52:04 iz8vb4rhbik3h93v48ztfvz systemd[1]: docker service delay has expired, a restart is planned.
Jun 15 23:52:04 iz8vb4rhbik3h93v48ztfvz systemd: Docker application container engine stopped.
Jun 15 23:52:04 iz8vb4rhbik3h93v48ztfvz systemd[1]: docker startup request repeats too fast. iz8vb4rhbik3h93v48ztfvz systemd[1]: docker application container engine failed to start.
Jun 15 23:52:04 iz8vb4rhbik3h93v48ztfvz systemd[1]: unit docker. the service entered a failed state.
Jun 15 23:52:04 iz8vb4rhbik3h93v48ztfvz systemd[1]: docker service failed. Start docker.
Job to docker. Service failed because it tried to start the service too many times. See “systemctl state docker”. Services” and “journalctl -xe” for more information.
To force startup use “systemctl reset-failed docker”. Followed by “systemctl reset-failed docker”. Service” is now enabled.

The reason is that the daemon.json file has been modified and needs to be modified again.

After modification by mv command, the dock worker will start normally.

[root@iz8vb4rhbik3h93v48ztfvz docker]# mv daemon.json daemon.conf
[root@iz8vb4rhbik3h93v48ztfvz docker]# systemctl start docker
[root@iz8vb4rhbik3h93v48ztfvz docker]# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
   Active: active (running) since Mon 2020-06-15 23:53:59 CST; 4s ago
     Docs: https://docs.docker.com
 Main PID: 9510 (dockerd)
    Tasks: 10
   Memory: 50.6M
   CGroup: /system.slice/docker.service
           └─9510 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

Jun 15 23:53:58 iz8vb4rhbik3h93v48ztfvz dockerd[9510]: time="2020-06-15T23:53:58.554833629+08:00" level=info msg="ccResolverWrapper: sending update to cc: {[{unix:///run/contain...module=grpc
Jun 15 23:53:58 iz8vb4rhbik3h93v48ztfvz dockerd[9510]: time="2020-06-15T23:53:58.554857738+08:00" level=info msg="ClientConn switching balancer to \"pick_first\"" module=grpc
Jun 15 23:53:58 iz8vb4rhbik3h93v48ztfvz dockerd[9510]: time="2020-06-15T23:53:58.570959343+08:00" level=info msg="[graphdriver] using prior storage driver: overlay2"
Jun 15 23:53:58 iz8vb4rhbik3h93v48ztfvz dockerd[9510]: time="2020-06-15T23:53:58.898909596+08:00" level=info msg="Loading containers: start."
Jun 15 23:53:59 iz8vb4rhbik3h93v48ztfvz dockerd[9510]: time="2020-06-15T23:53:59.152882347+08:00" level=info msg="Default bridge (docker0) is assigned with an IP address 172.17....IP address"
Jun 15 23:53:59 iz8vb4rhbik3h93v48ztfvz dockerd[9510]: time="2020-06-15T23:53:59.245906513+08:00" level=info msg="Loading containers: done."
Jun 15 23:53:59 iz8vb4rhbik3h93v48ztfvz dockerd[9510]: time="2020-06-15T23:53:59.283200393+08:00" level=info msg="Docker daemon" commit=afacb8b graphdriver(s)=overlay2 version=19.03.8
Jun 15 23:53:59 iz8vb4rhbik3h93v48ztfvz dockerd[9510]: time="2020-06-15T23:53:59.289824517+08:00" level=info msg="Daemon has completed initialization"
Jun 15 23:53:59 iz8vb4rhbik3h93v48ztfvz dockerd[9510]: time="2020-06-15T23:53:59.320315408+08:00" level=info msg="API listen on /var/run/docker.sock"
Jun 15 23:53:59 iz8vb4rhbik3h93v48ztfvz systemd[1]: Started Docker Application Container Engine.
Hint: Some lines were ellipsized, use -l to show in full.

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