LibreNMS is becoming one of my favorite monitoring tools. Setup and getting started is easy and it has enough advanced options and tunables. I recently discovered that LibreNMS is able to check services as well. Services, in this context, means, executing Nagios plugins (like check_http, check_ping, etc). This allows you to check services that SNMP does not cover by default, like HTTP(s) health checks, certificate expiry, tcp port checks (e.g. rdp) and anything for which you can write a Nagios plugin yourself. The performance data, if available, is graphed automatically. Alerting is done with the regular LibreNMS alerts. This guide covers the setup of services (it's not enabled by default) and a few basic checks, like an http health check, certificate expiry and SSH monitoring.