Icinga

Icinga is an open-source monitoring system and alerting framework derived from Nagios. It observes hosts, services, and network resources, sending notifications to on-call staff if thresholds are breached. A modular design supports plugins and multiple data outputs. Icinga suits enterprises or advanced sysadmins wanting a free, highly customizable solution for real-time monitoring that can integrate with on-call or escalation tools for incident management workflows.