Date Added: Nov 2012
Monitoring is a core function of systems administration, and is primarily a problem of communication - a good monitoring tool communicates with users about problems, and communicates with hosts and software to take remedial action. The better it communicates, the greater the confidence administrators will have in its view of their environment. Nagios has been a leading open-source monitoring solution for over a decade, but in that time, the way it gets data in and out of its scheduling engine hasn't changed. As applications are written to extend Nagios, each one has to figure out its own way of getting data out of the Nagios core process.