Prometheus is a metrics based monitoring system. Instead of executing plugins and checking for return codes like Nagios or Naemon does, Prometheus focus on collecting metrics at a high frequency.

Prometheus is seamlessly integrated into openITCOCKPIT including a interface to define alert rules.

It is even possible to mix traditional monitoring and Prometheus monitoring together on the same host. Sky's the limit.

https://github.com/prometheus/prometheus

Documentation: https://docs.openitcockpit.io/monitoring/prometheus/