This should be easy, because there's a squillion questions about it, but seemingly I'm missing something. I have a script that creates some directories that I need to run at boot time. It's way too simple to bother with figuring out upstart or anything - it's not a service, it doesn't need monitoring, it just needs to run at boot time, with superuser privileges. I've tried putting the script directly in /etc/rc2.d - it ran once, at one boot, and never again. Does the system somehow remember it ran and didn't get shut down or whatever? I've also added a cron job as root and added the script as an @reboot task, still no dice. This is on an s3 Ubuntu instance - do s3 instances have some bizarre way of booting up that is causing these simple things not to work?
edit: I should mention that I need this script to run as early as possible at boot, since among other things it sets up /tmp, which is a bit important to a number of parts of the system.