Shinken is a modern open source Nagios® like tool, redesigned and rewritten from scratch. Its main goal is to meet today’s system monitoring requirements while still allowing compatibility to Nagios®. Feature comparison between Shinken and Nagios.
You can monitor nearly anything in your IT, even end user apps! Everything is done using Agents, Plugins (there are a lot of them!) and native Shinken poller modules. If you need to check something really specific in your environnement, you can create a new plugin just by writing a few lines of script!