Eddie! Eddie!

The EDDIE Tool:

a system monitoring, security and performance analysis agent developed entirely in Python.

Looks nice: you can add extra rules which can arbitrary python expressions (and thus arbitrarily complex), and it does all the usual stuff you’d expect, such as SNMP. The author also suggests Pythonistas might find it interesting as…

an example of a threaded, multi-platform software package, providing easy access to system statistics and using Python’s power to offer a dynamic and programmable rules engine.

Well, I wouldn’t know about that sir.