I had the deep misfortune of being involved in finding a rather insane behavior in a semi-custom database high-availability solution.
The core bits were unremarkable. Red Hat Enterprise Linux, MySQL, DRBD, and the Linux-HA stuff. The configuration, however, was maintained by a completely custom puppet-like system (unsurprisingly, there are many other examples of insanity resulting from this system).
It turns out that the system was checking the install.log file that Kickstart leaves in the root directory for part of the information it needed to create the DRBD configuration. This in itself is evil, of course. You don't pull configuration from a log file whose format is not actually defined. It gets worse, though.
It didn't store this data anywhere else, and every time it ran, which was every 60 seconds, it consulted install.log.
I'll just let you guess what happened the first time somebody decided to delete this otherwise useless log file.
