centos7.2 docker 安装 启动报错 Failed to start Docker Application Container Engine

Failed to start Docker Application Container Engine.

下面是我启动成功后，为了记录下前面的错误，故意将daemon.conf  重新改为daemon.json，启动失败的记录

以供大家学习！

[root@izhp37s2whf1q1c504etzsz docker]# mv daemon.json daemon.conf
[root@izhp37s2whf1q1c504etzsz docker]# ll
total 8
-rw-r--r-- 1 root root 250 Apr 22 16:48 daemon.conf
-rw------- 1 root root 244 Apr 11 18:02 key.json
[root@izhp37s2whf1q1c504etzsz docker]# service docker start
Redirecting to /bin/systemctl start  docker.service
[root@izhp37s2whf1q1c504etzsz docker]# docker version
Client:
 Version:           18.09.4
 API version:       1.39
 Go version:        go1.10.8
 Git commit:        d14af54266
 Built:             Wed Mar 27 18:34:51 2019
 OS/Arch:           linux/amd64
 Experimental:      false

Server: Docker Engine - Community
 Engine:
  Version:          18.09.5
  API version:      1.39 (minimum version 1.12)
  Go version:       go1.10.8
  Git commit:       e8ff056
  Built:            Thu Apr 11 04:13:40 2019
  OS/Arch:          linux/amd64
  Experimental:     false
[root@izhp37s2whf1q1c504etzsz docker]# systemctl status docker.service
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled)
   Active: active (running) since Mon 2019-04-29 16:20:48 CST; 28s ago
     Docs: https://docs.docker.com
 Main PID: 30693 (dockerd)
   Memory: 67.2M
   CGroup: /system.slice/docker.service
           └─30693 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

Apr 29 16:20:48 izhp37s2whf1q1c504etzsz dockerd[30693]: time="2019-04-29T16:20:48.155193460+08:00" level=info msg
Apr 29 16:20:48 izhp37s2whf1q1c504etzsz dockerd[30693]: time="2019-04-29T16:20:48.253166703+08:00" level=info msg
Apr 29 16:20:48 izhp37s2whf1q1c504etzsz dockerd[30693]: time="2019-04-29T16:20:48.253755449+08:00" level=info msg
Apr 29 16:20:48 izhp37s2whf1q1c504etzsz dockerd[30693]: time="2019-04-29T16:20:48.683450718+08:00" level=info msg
Apr 29 16:20:48 izhp37s2whf1q1c504etzsz dockerd[30693]: time="2019-04-29T16:20:48.820424124+08:00" level=info msg
Apr 29 16:20:48 izhp37s2whf1q1c504etzsz dockerd[30693]: time="2019-04-29T16:20:48.946641305+08:00" level=warning 
Apr 29 16:20:48 izhp37s2whf1q1c504etzsz dockerd[30693]: time="2019-04-29T16:20:48.946862319+08:00" level=info msg
Apr 29 16:20:48 izhp37s2whf1q1c504etzsz dockerd[30693]: time="2019-04-29T16:20:48.948921751+08:00" level=info msg
Apr 29 16:20:48 izhp37s2whf1q1c504etzsz systemd[1]: Started Docker Application Container Engine.
Apr 29 16:20:48 izhp37s2whf1q1c504etzsz dockerd[30693]: time="2019-04-29T16:20:48.969478346+08:00" level=info msg
Hint: Some lines were ellipsized, use -l to show in full.
[root@izhp37s2whf1q1c504etzsz docker]# ll
total 8
-rw-r--r-- 1 root root 250 Apr 22 16:48 daemon.conf
-rw------- 1 root root 244 Apr 11 18:02 key.json
[root@izhp37s2whf1q1c504etzsz docker]# systemctl stop docker.service
[root@izhp37s2whf1q1c504etzsz docker]# ll
total 8
-rw-r--r-- 1 root root 250 Apr 22 16:48 daemon.conf
-rw------- 1 root root 244 Apr 11 18:02 key.json
[root@izhp37s2whf1q1c504etzsz docker]# mv daemon.conf daemon.json
[root@izhp37s2whf1q1c504etzsz docker]# systemctl start docker.service
Job for docker.service failed because the control process exited with error code. See "systemctl status docker.service" and "journalctl -xe" for details.
[root@izhp37s2whf1q1c504etzsz docker]# systemctl status docker.service
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled)
   Active: failed (Result: start-limit) since Mon 2019-04-29 16:33:10 CST; 11s ago
     Docs: https://docs.docker.com
  Process: 30865 ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock (code=exited, status=1/FAILURE)
 Main PID: 30865 (code=exited, status=1/FAILURE)

Apr 29 16:33:08 izhp37s2whf1q1c504etzsz systemd[1]: docker.service: main process exited, code=exited, stat...URE
Apr 29 16:33:08 izhp37s2whf1q1c504etzsz systemd[1]: Failed to start Docker Application Container Engine.
Apr 29 16:33:08 izhp37s2whf1q1c504etzsz systemd[1]: Unit docker.service entered failed state.
Apr 29 16:33:08 izhp37s2whf1q1c504etzsz systemd[1]: docker.service failed.
Apr 29 16:33:10 izhp37s2whf1q1c504etzsz systemd[1]: docker.service holdoff time over, scheduling restart.
Apr 29 16:33:10 izhp37s2whf1q1c504etzsz systemd[1]: start request repeated too quickly for docker.service
Apr 29 16:33:10 izhp37s2whf1q1c504etzsz systemd[1]: Failed to start Docker Application Container Engine.
Apr 29 16:33:10 izhp37s2whf1q1c504etzsz systemd[1]: Unit docker.service entered failed state.
Apr 29 16:33:10 izhp37s2whf1q1c504etzsz systemd[1]: docker.service failed.
Hint: Some lines were ellipsized, use -l to show in full.
[root@izhp37s2whf1q1c504etzsz docker]#