[Sarki]

And that's why you must monitor your servers health. You know, for when they're starting to act funny.

I'm not related in any way with them but as a personnal favorite (I even use it at home) I'd recommend Zabbix as it's open source and quite straighforward to install and deploy its agents, once configured you can even forget about it.

Gosh, its default alerts will give you hints on things you never considered checking before while the integration of new/bespoke software can be done in a matter of minutes.