rubber-docker/linux.c. rubber-docker is a workshop that talks through building a simply Docker clone from scratch in Python. I particularly liked this detail: linux.c is a Python extension written in C that exposes a small collection of Linux syscalls that are needed for the project—clone, mount, pivot_root, setns, umount, umount2 and unshare. Just reading through this module gives a really nice overview of how some of Docker’s underlying magic actually work.