[root@web-dev1 system]# systemctl daemon-reload
[root@web-dev1 system]# systemctl start 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@web-dev1 system]# systemctl status docker.service
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
   Active: failed (Result: start-limit) since Thu 2021-09-02 08:51:20 CST; 1min 32s ago
     Docs: https://docs.docker.com
  Process: 20308 ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock -H tcp://0.0.0.0:2375 -H unix://var/run/docker.sock (code=exited, status=1/FAILURE)
 Main PID: 20308 (code=exited, status=1/FAILURE)

Sep 02 08:51:17 web-dev1 systemd[1]: Failed to start Docker Application Container Engine.
Sep 02 08:51:17 web-dev1 systemd[1]: Unit docker.service entered failed state.
Sep 02 08:51:17 web-dev1 systemd[1]: docker.service failed.
Sep 02 08:51:20 web-dev1 systemd[1]: docker.service holdoff time over, scheduling restart.
Sep 02 08:51:20 web-dev1 systemd[1]: Stopped Docker Application Container Engine.
Sep 02 08:51:23 web-dev1 systemd[1]: start request repeated too quickly for docker.service
Sep 02 08:51:23 web-dev1 systemd[1]: Failed to start Docker Application Container Engine.
Sep 02 08:51:23 web-dev1 systemd[1]: Unit docker.service entered failed state.
Sep 02 08:51:23 web-dev1 systemd[1]: docker.service failed.

[root@web-dev1 system]# vim /usr/lib/systemd/system/docker.service

  1 [Unit]
  2 Description=Docker Application Container Engine
  3 Documentation=https://docs.docker.com
  4 After=network-online.target firewalld.service containerd.service
  5 Wants=network-online.target
  6 Requires=docker.socket containerd.service
  7 
  8 [Service]
  9 Type=notify
 10 # the default is not to use systemd for cgroups because the delegate issues still
 11 # exists and systemd currently does not support the cgroup feature set required
 12 # for containers run by docker
 13 # ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
 14 ExecStart=/usr/bin/dockerd
 15 ExecReload=/bin/kill -s HUP $MAINPID
 16 TimeoutSec=0
 17 RestartSec=2
 18 Restart=always
 19 

[root@web-dev1 system]# vim /etc/docker/daemon.json 

  1 {
  2     "registry-mirrors": ["https://dockerhub.azk8s.cn","https://hub-mirror.c.163.com"],
  3     "exec-opts": ["native.cgroupdriver=cgroupfs"],
  4     "log-driver": "json-file",
  5     "log-opts": {"max-size": "10m","max-file": "10"},
  6     "insecure-registries": ["1.1.1.1:2021"],
  7     "hosts": ["tcp://0.0.0.0:2375", "unix:///var/run/docker.sock"]
  8 }

[root@web-dev1 system]# systemctl daemon-reload
[root@web-dev1 system]# systemctl start docker

[root@web-dev1 system]# docker images
REPOSITORY   TAG       IMAGE ID   CREATED   SIZE
[root@web-dev1 system]# vim /etc/docker/daemon.json 
[root@web-dev1 system]# lsof -i:2375
COMMAND   PID USER   FD   TYPE    DEVICE SIZE/OFF NODE NAME
dockerd 30865 root    9u  IPv6 285808116      0t0  TCP *:2375 (LISTEN)
[root@web-dev1 system]# 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 Thu 2021-09-02 09:00:45 CST; 2min 24s ago
     Docs: https://docs.docker.com
 Main PID: 30865 (dockerd)
    Tasks: 13
   Memory: 28.0M
   CGroup: /system.slice/docker.service
           └─30865 /usr/bin/dockerd

Sep 02 09:00:44 web-dev1 dockerd[30865]: time="2021-09-02T09:00:44.901936855+08:00" level=info msg="ClientConn switching balancer to \"pick_first...dule=grpc
Sep 02 09:00:44 web-dev1 dockerd[30865]: time="2021-09-02T09:00:44.915442870+08:00" level=info msg="[graphdriver] using prior storage driver: overlay2"
Sep 02 09:00:44 web-dev1 dockerd[30865]: time="2021-09-02T09:00:44.924126668+08:00" level=info msg="Loading containers: start."
Sep 02 09:00:45 web-dev1 dockerd[30865]: time="2021-09-02T09:00:45.069987957+08:00" level=info msg="Default bridge (docker0) is assigned with an ... address"
Sep 02 09:00:45 web-dev1 dockerd[30865]: time="2021-09-02T09:00:45.130848024+08:00" level=info msg="Loading containers: done."
Sep 02 09:00:45 web-dev1 dockerd[30865]: time="2021-09-02T09:00:45.167723153+08:00" level=info msg="Docker daemon" commit=75249d8 graphdriver(s)=...n=20.10.8
Sep 02 09:00:45 web-dev1 dockerd[30865]: time="2021-09-02T09:00:45.167817837+08:00" level=info msg="Daemon has completed initialization"
Sep 02 09:00:45 web-dev1 systemd[1]: Started Docker Application Container Engine.
Sep 02 09:00:45 web-dev1 dockerd[30865]: time="2021-09-02T09:00:45.197823106+08:00" level=info msg="API listen on [::]:2375"
Sep 02 09:00:45 web-dev1 dockerd[30865]: time="2021-09-02T09:00:45.202916732+08:00" level=info msg="API listen on /var/run/docker.sock"
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