Icinga

Icinga started as a fork of Nagios and has grown into a full-featured monitoring platform. The core daemon, Icinga 2, can check hosts and services using standard monitoring plugins or custom scripts. It supports distributed setups where one master node collects results from satellite nodes, making it easier to monitor large environments. Configuration is done in a DSL or via the Icinga Director module, which provides a web interface for managing hosts and services. Performance data can be sent to graphing tools like Graphite, InfluxDB, or RRDtool. Icinga includes a REST API for integration with external systems, and notifications can be sent through email, Slack, PagerDuty, and other channels. The Icinga Web 2 frontend gives you dashboards, reports, and real-time views of your monitored infrastructure. It runs on Linux and Windows, and plugins exist for everything from network devices to databases to cloud services. The project is developed by Icinga GmbH and licensed under the GPLv2. For teams that want a scalable, open alternative to proprietary monitoring tools, Icinga offers a solid foundation with optional enterprise support and extensions.