Shinken
Shinken is an open source computer system and network monitoring software application compatible with Nagios. It's written in Python and therefore is able to run on all platforms where a Python interpreter is available. In contrast to Nagios it is not a monolithic system. Shinken runs as a bunch of highly specialized processes, avoiding the bottlenecks of a single-process design. This parallelity allows to run Shinken not only on one single server. It's components can be distributed over a whole server farm, which results in incredible scalability. Shinken is actively developed and already got more features than Nagios (like priorities for objects, business processes, auto-generation of services, discovery,...)
