I have a bunch (hundreds) of low-end machines running Linux (mostly Ubuntu and CentOS distributions) spread out all over the world that I don't like to SSH into very often. I would like, however, to be able to go to a webpage and get a view of each machine's individual health. Things like memory usage, CPU usage, network usage, if updates are available, etc. I'd also like a big button to click that has them perform any upgrades.
Nagios looks like it does a lot of what I want, but it also looks pretty heavy. Is there a more light-weight solution that I can use?