Quick guide on how to create a lightweight systemd container for Arch Linux, using systemd-nspawn and pacstrap, in under 1 minute!
pacman -S arch-install-scripts mkdir /srv/subarch pacstrap -c -d /srv/subarch base systemd-nspawn -bD /srv/subarch
And that's it! Log in as "root" with no password.
You can remove the kernel to save space within the container. DO NOT RUN THIS ON THE HOST!
pacman -Rsn linux
Once you're done with the container just shut it down with poweroff