Greetings, all!

I'm trying to setup a kiosk-like, resettable environment using overlayroot. The standard configuration for overlayroot uses tmpfs, and that works great except I need my users to have more space than my machines have RAM. I seem to have overlayroot working with a separate partition, rather than tmpfs, with one small problem - I need to wipe out all changes on the upper filesystem between reboots.

I think the most reliable strategy would be to do this "wipe" on bootup as early as possible, but I'm not sure the right way to actually do that. Can anyone point me in the right direction?