鈼 mongod.service - MongoDB Database Server

   Loaded: loaded (/usr/lib/systemd/system/mongod.service; enabled; vendor preset: disabled)

   Active: failed (Result: exit-code) since Tue 2022-08-23 10:11:48 CST; 18s ago

     Docs: https://docs.mongodb.org/manual

  Process: 9278 ExecStart=/usr/bin/mongod $OPTIONS (code=exited, status=14)

  Process: 9275 ExecStartPre=/usr/bin/chmod -R 0755 /app/mongodb (code=exited, status=0/SUCCESS)

  Process: 9272 ExecStartPre=/usr/bin/chown -R mongod:mongod /app/mongodb (code=exited, status=0/SUCCESS)

  Process: 9270 ExecStartPre=/usr/bin/mkdir -p /app/mongodb (code=exited, status=0/SUCCESS)

 Main PID: 9278 (code=exited, status=14)

 systemd[1]: Starting MongoDB Database Server...

systemd[1]: Started MongoDB Database Server.

 mongod[9278]: about to fork child process, waiting until server is ready for connections.

 mongod[9278]: forked process: 9281

  mongod[9278]: ERROR: child process failed, exited with 14

 mongod[9278]: To see additional information in this output, start without the "--fork" option.

 systemd[1]: mongod.service: main process exited, code=exited, status=14/n/a

 systemd[1]: Unit mongod.service entered failed state.

 systemd[1]: mongod.service failed.

mongodb   用systemctl 启动的时候， 报这个错误。 

这个时候， 是需要注意几个权限问题的。 

data  目录读写权限    

软件可行性权限。 

启动用户对不对。

还有很重要的一个  /tmp 下面的 socket 文件的读写权限。 

看看这几个地方的权限问题 ，基本上就解决了