This is a project I made over the weekend. What if when you SSH'd into a machine, instead of giving you a user login, it would provision a new microVM just for you?

It's like a little SimCity for VMs.

This turned out to be a lot of fun, and I've wanted to make my own custom SSH server for a while now, with its fancy progress bars and color animations. The hardest part was definitely debugging VM setup, boot, and networking though! Compiling the Linux kernel with all the right configs was difficult. For a while I had issues with silent hangs on boot due to lack of available system entropy, on Linux <4.19. Anyway, I wrote a bit about my struggles. :D

I managed to bundle everything (vmlinux 6.1, firecracker, SSH server, iptables/bridge/masquerade) into a single, statically-linked binary for x86_64/aarch64. It takes the kernel rootfs as a command-line argument.