Harpseal

The Harpseal API allows developers to create a cluster monitoring system for their Linux systems. The API can also be used to graph and analyze collected data. Harpseal was created to collect system resources, usage, and more via extendable plugins. It is provided as a light-weight alternative to munin, mrtg, etc. Harpseal is a 'A next generation linux monitoring tool based on plugins.' and is easy to install and free to use, even for commercial purposes.