[root@VM_0_11_centos /]# systemctl status mongod.service
● mongod.service - High-performance, schema-free document-oriented database
   Loaded: loaded (/usr/lib/systemd/system/mongod.service; enabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since 三 2018-03-14 21:11:18 CST; 9s ago
     Docs: https://docs.mongodb.org/manual
  Process: 20510 ExecStart=/usr/bin/mongod $OPTIONS (code=exited, status=2)
  Process: 20508 ExecStartPre=/usr/bin/chmod 0755 /var/run/mongodb (code=exited, status=0/SUCCESS)
  Process: 20505 ExecStartPre=/usr/bin/chown mongod:mongod /var/run/mongodb (code=exited, status=0/SUCCESS)
  Process: 20504 ExecStartPre=/usr/bin/mkdir -p /var/run/mongodb (code=exited, status=0/SUCCESS)

3月 14 21:11:18 VM_0_11_centos systemd[1]: Starting High-performance, schema-free document-oriented database...
3月 14 21:11:18 VM_0_11_centos systemd[1]: mongod.service: control process exited, code=exited status=2
3月 14 21:11:18 VM_0_11_centos systemd[1]: Failed to start High-performance, schema-free document-oriented database.
3月 14 21:11:18 VM_0_11_centos systemd[1]: Unit mongod.service entered failed state.
3月 14 21:11:18 VM_0_11_centos systemd[1]: mongod.service failed.