解決Monit啟動監控進程消失monit.service failed.

Monit監控軟件啟動時無法啟動監控。

Monit啟動監控進程消失提示monit.service fai引領。

在CWP控制面板（CWP7）安裝Monit監控軟件後，Monit啟動監控進程消失，出現提示：monit.service failed.

值得注意的是，已經嘗試啟用過了systemctl enable monit

[root@stage-web-1 vagrant]# systemctl status monit
monit.service - Pro-active monitoring utility for unix systems
Loaded: loaded (/usr/lib/systemd/system/monit.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Thu 2017-06-01 16:37:00 UTC; 6min ago
Process: 1131 ExecStop=/usr/bin/monit quit (code=exited, status=1/FAILURE)
Process: 1079 ExecStart=/usr/bin/monit -I (code=exited, status=1/FAILURE)
Main PID: 1079 (code=exited, status=1/FAILURE)

Jun 01 16:37:00 stage-web-1 systemd[1]: Started Pro-active monitoring utility for unix systems.
Jun 01 16:37:00 stage-web-1 systemd[1]: Starting Pro-active monitoring utility for unix systems...
Jun 01 16:37:00 stage-web-1 monit[1079]: Error opening the log file '/var/www/html/nfs/monit/stage-web-1.log' for writing -- No such file or directory
Jun 01 16:37:00 stage-web-1 systemd[1]: monit.service: main process exited, code=exited, status=1/FAILURE
Jun 01 16:37:00 stage-web-1 monit[1131]: Error opening the log file '/var/www/html/nfs/monit/stage-web-1.log' for writing -- No such file or directory
Jun 01 16:37:00 stage-web-1 systemd[1]: monit.service: control process exited, code=exited status=1
Jun 01 16:37:00 stage-web-1 systemd[1]: Unit monit.service entered failed state.
Jun 01 16:37:00 stage-web-1 systemd[1]: monit.service failed.

事實說明，它/var/www/html/nfs是通過NFS安裝到網絡驅動器的文件夾。

Monit是在NFS之前啟動的，因此該文件夾尚不存在，從而導致monit錯誤Error opening the log file '/var/www/html/nfs/monit/stage-web-1.log' for writing -- No such file or directory。

如何解決Monit啟動監控進程消失monit.service failed.？

解決方法是編輯/lib/systemd/system/monit.service：

[Unit]
Description=Pro-active monitoring utility for unix systems
After=network.target

[Service]
Type=simple
ExecStart=/usr/bin/monit -I
ExecStop=/usr/bin/monit quit
ExecReload=/usr/bin/monit reload

[Install]
WantedBy=multi-user.target

並添加nfs.service到该After後面。最終結果如下所示：

[Unit]
Description=Pro-active monitoring utility for unix systems
After=network.target nfs.service

[Service]
Type=simple
ExecStart=/usr/bin/monit -I
ExecStop=/usr/bin/monit quit
ExecReload=/usr/bin/monit reload

[Install]
WantedBy=multi-user.target

Monit監控程序現在可以在啟動時，成功啟動了。