Hi,
I previously wrote here about a jail-like feature for NetBSD. Unfortunately, I'm not coming with such software (yet). However, I did create my own "chroot management system" over the last few months. If some of you might be interested in such a thing have a look here:
https://gitlab.com/jusavard/captain/.
It"s all shell scripts inspired by "sailor" with some behavior from Solaris Zones and some terminology from docker. Nothing too much complicated (well in my opinion).
Feel free to send me your comments or even contribute if you want but please keep in mind it is still under development.