Icinga 2 which was initially released around July 2014. Icinga is a fork of the Nagios monitoring system, meaning that it can do periodic checks to servers, services and networks to make sure everything is running smoothly. If not, it can e-mail, text or phone a system administrator.
Staying close to Nagios syntax had its comforts, but it also meant keeping some of its limitations. Icinga 2 is more of a complete rewrite. The documentation keeps talking about node communication with SSL and a 12 step program to get started... with nodes. What if you just want to convert your Icinga 1 configuration and see how it goes?