A design goal of mon is to maintain simplicity and provide the right abstractions for monitoring so that the system can be scalable, easy to use, and trivial to extend for the widest variety of applications. The learning curve is very shallow for initial installation, configuration, and customization. Monitors and alerts are simple to write using any language, and simple to incorporate into a site configuration. Reporting and control functionality is easily customized with the aid of a TCP-based protocol interface.
Mon is Open Source software, and distributed under the GNU Public License version 2.
Please see the wiki for the latest information.