This post contains the information I have missed when I have started to use iocage for jails management on FreeBSD.

Disclaimer: I am relatively new to FreeBSD and while what is written below works for me it is most probably not the only (or even a right) way to do things.

Jails

Jails is a killer feature of FreeBSD. One can think about jail as about chroot on steroids, or as about a very light-weight virtual machine. A jail provides an environment isolated from the rest of the system where FreeBSD is running (usually; one can run, for example, Linux in a jail).