【问题描述】：Mongodb无法正常启动

[root@host01 mongo]# systemctl start mongod.service

Job for mongod.service failed because a timeout was exceeded. See "systemctl status mongod.service" and "journalctl -xe" for details.[root@host01 mongo]# systemctl status mongod.service● mongod.service - High-performance, schema-free document-oriented databaseLoaded: loaded (/usr/lib/systemd/system/mongod.service; enabled; vendor preset: disabled)Active: failed (Result: timeout) since Tue 2019-03-19 15:15:55 CST; 53s agoDocs: Process: 19756 ExecStart=/usr/bin/mongod $OPTIONS (code=exited, status=0/SUCCESS)Main PID: 6936 (code=killed, signal=KILL)

Mar 19 15:14:17 host01 systemd[1]: Starting High-performance, schema-free document-oriented database...

Mar 19 15:14:17 host01 mongod[19756]: about to fork child process, waiting until server is ready for connections.Mar 19 15:14:17 host01 mongod[19756]: forked process: 19761Mar 19 15:15:23 host01 mongod[19756]: child process started successfully, parent exitingMar 19 15:15:54 host01 systemd[1]: mongod.service start operation timed out. Terminating.Mar 19 15:15:55 host01 systemd[1]: Failed to start High-performance, schema-free document-oriented database.Mar 19 15:15:55 host01 systemd[1]: Unit mongod.service entered failed state.Mar 19 15:15:55 host01 systemd[1]: mongod.service failed.

[root@host01 mongo]# systemctl status mongod.service

● mongod.service - High-performance, schema-free document-oriented databaseLoaded: loaded (/usr/lib/systemd/system/mongod.service; enabled; vendor preset: disabled)Active: active (running) since Tue 2019-03-19 15:16:52 CST; 2s agoDocs: Process: 21843 ExecStartPre=/usr/bin/chmod 0755 /var/run/mongodb (code=exited, status=0/SUCCESS)Process: 21832 ExecStartPre=/usr/bin/chown mongod:mongod /var/run/mongodb (code=exited, status=0/SUCCESS)Process: 21830 ExecStartPre=/usr/bin/mkdir -p /var/run/mongodb (code=exited, status=0/SUCCESS)Main PID: 21847 (mongod)Tasks: 15Memory: 284.1MCGroup: /system.slice/mongod.service├─21847 /usr/bin/mongod -f /etc/mongod.conf├─21858 /usr/bin/mongod -f /etc/mongod.conf└─21859 /usr/bin/mongod -f /etc/mongod.conf

Mar 19 15:16:52 host01 systemd[1]: Starting High-performance, schema-free document-oriented database...

Mar 19 15:16:52 host01 systemd[1]: Started High-performance, schema-free document-oriented database.Mar 19 15:16:52 host01 mongod[21847]: about to fork child process, waiting until server is ready for connections.Mar 19 15:16:52 host01 mongod[21847]: forked process: 21859[root@host01 mongo]#

【解决方案】

将service中的以下内容进行注释即可Type=forking

[root@host01 mongo]# systemctl start mongod.service

[root@host01 mongo]# systemctl status mongod.service

● mongod.service - High-performance, schema-free document-oriented databaseLoaded: loaded (/usr/lib/systemd/system/mongod.service; enabled; vendor preset: disabled)Active: active (running) since Tue 2019-03-19 15:16:52 CST; 2s agoDocs: Process: 21843 ExecStartPre=/usr/bin/chmod 0755 /var/run/mongodb (code=exited, status=0/SUCCESS)Process: 21832 ExecStartPre=/usr/bin/chown mongod:mongod /var/run/mongodb (code=exited, status=0/SUCCESS)Process: 21830 ExecStartPre=/usr/bin/mkdir -p /var/run/mongodb (code=exited, status=0/SUCCESS)Main PID: 21847 (mongod)Tasks: 15Memory: 284.1MCGroup: /system.slice/mongod.service├─21847 /usr/bin/mongod -f /etc/mongod.conf├─21858 /usr/bin/mongod -f /etc/mongod.conf└─21859 /usr/bin/mongod -f /etc/mongod.conf

Mar 19 15:16:52 host01 systemd[1]: Starting High-performance, schema-free document-oriented database...

Mar 19 15:16:52 host01 systemd[1]: Started High-performance, schema-free document-oriented database.Mar 19 15:16:52 host01 mongod[21847]: about to fork child process, waiting until server is ready for connections.Mar 19 15:16:52 host01 mongod[21847]: forked process: 21859[root@host01 mongo]#