> I took a look and I think it requires software running on
> each guest to report the data back to the centralized
> system.  Is that correct?
Yes
> If so, I am looking for a solution that does not require
> any software on the guest machines.
Oh well, it is not for you then.  But it is a pretty sweet system for
monitoring your boxes - easy to write your own plugins so the only
limit is your imagination.
-- 
“Don't eat anything you've ever seen advertised on TV”
         - Michael Pollan, author of "In Defense of Food"