unionfs and diskless linux

Back to work, today I helped my coworkers setup a diskless linux system. As usual, it mounts root over NFS. But in our case, there's a nice twist; each host nfs-mounts both a shared readonly filesystem and a private writable one. We then use unionfs to overlay the two filesystems. I actually spent most of the afternoon tweaking initramfs to accomplish this effect, but the result pays off. We now can instantly boot any machine we want just by configuring the DHCP server, and each PC can customize its own filesystem, or else just inherit from the shared one. We get the best of both worlds: installing software once on the server makes it available to all clients, but clients can still be easily customized (unlike, say, lessdisks).