Mon is a general-purpose resource monitoring system. It can be used
to monitor network service availability, server problems,
environmental conditions (i.e., the temperature in a room) or other
things. Mon can be used to test the condition and/or to trigger an
action upon failure of the condition. Mon keeps the testing and
action-taking tasks as separate, stand-alone programs.
Mon is very extensible. Monitors and alerts are not a part of mon, but
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
required, the mon server will not need to be changed.