Icinga

https://icinga.com/

Icinga monitors availability and performance, gives you simple access to relevant data and raises alerts to keep you in the loop.

Snippet from Wikipedia: Icinga

Icinga is an open-source computer system and network monitoring application. It was originally created as a fork of the Nagios system monitoring application in 2009.

Icinga is attempting to get past perceived short-comings in Nagios' development process, as well as adding new features such as a modern Web 2.0 style user interface, additional database connectors (for MySQL, Oracle, and PostgreSQL), and a REST API that lets administrators integrate numerous extensions without complicated modification of the Icinga core.

The Icinga developers also seek to reflect community needs more closely and to integrate patches more quickly. The first stable version, 1.0, was released in December 2009, and the version counter had risen every couple of months as of January 2010.

Icinga was included by Jeffrey Hammond of Forrester Research in a list of "waxing" (as opposed to "waning") open source projects based on its rate of commits.

The name Icinga is a Zulu word meaning "it looks for", "it browses" or "it examines" and is pronounced with a click consonant.