What is "mon"?

mon views resource monitoring as two separate tasks: the testing of a condition, and triggering an action upon failure. mon was designed to implement the testing and action-taking tasks as separate, stand-alone programs. mon is fundamentally a scheduler which executes the monitors (each test a specific condition), and calls the appropriate alerts if the monitor fails. The decision to invoke an alert is governed by logic which offers various "squelch" features and dependencies, all of which are configurable by the user.

Monitors and alerts are not a part of the core mon server, even though the distribution comes with a handful of them to get you started. This means that if a new service needs monitoring, or if a new alert is necessary, the mon server does not need to be changed. This makes mon easily extensible.