Check_MK is an extension to the Nagios monitoring system that allows creating rule-based configuration using Python and offloading work from the Nagios core to make it scale better, allowing more systems to be monitored from a single Nagios server.
check-mk is a comprehensive, open-source addon for the monitoring software nagios. The extension is offloading work from the Nagios core to make it scale better, allowing more systems to be monitored from a single Nagios server. You can integrate check-mk into your existing Nagios/Icinga environment.
check-mk simplifies the configuration and makes monitoring with Nagios much more efficient.
check-mk is fully open source and available under the terms of the GNU GPL.