A tool to monitor and ensure server's services are running and responding

A useful tool to monitor and ensure that services are running

System Integrity Monitor

-to monitor system resources, and setup to send you email alerts.
Servers running CPanel already have a service monitoring script running by default, called CHKSERVD. SIM may still be useful for CPanel users for it's monitoring and alert system. You should disable the auto-restart of downed services if you are running CPanel.

Alternative tools:

Monit

Monit can start a process if it does not run, restart a process if it does not respond and stop a process if it uses too much resources