Do you have a creative use for nagios?

I'm looking for inspirations on nonstandard uses of monitoring systems like nagios, which is normally used to check whether HTTP is reponding etc. I'm curious how people have taken the simple nagios framework and run with it in unexpected ways, so I can steal borrow them.

Solution 1:

I used to store a copy of my Facebook friends and Twitter followers list, and send Nagios alerts if I got unfriended / unfollowed.

Solution 2:

I use nagios to monitor a high-performance-computing Linux cluster of 1100 nodes. Nagios is used to check the sshd process, hard drive SMART status, Infiniband network status, shared filesystem and disk usage. If any of these tests fail, the node is automatically taken out of the job scheduler's production pool so it may be serviced. So far, this has worked fairly well. Before Nagios was implemented on the cluster, we had many complains that programs would fail to start or they would crash immediately. After it was implemented, we almost no complains.

I also use Nagios to monitor some Xen dom-U instances. If a dom-U VM would crash, Nagios would automatically reboot the VM.