[masom]

yup! FreeBSD jails are essentially what OP wants with chroot++.

I was pretty puzzled when Docker and LXC came around as this whole new thing believed to have "never been done before"; FreeBSD had supported a very similar concept for years before security groups were added in Linux.

Jails and ezjail were stellar to make mini no-overhead containers when running various services on a server. Being able to archive them and expand them on a new machine was also pretty cool (as long as the BSD version was the same.)

[microtonal]

this whole new thing believed to have "never been done before";

Nobody with knowledge of sandboxing believed this, Virtuozzo and later OpenVZ had been on Linux for a long time after all. Virtuozzo was even from a similar time frame as FreeBSD jails (2000-ish).

The key innovation of Docker was to provide a standardized way to build, distribute, and run container images.

[alfiedotwtf]

Virsh had worked for a long time before docker came around, but yeah… you essentially had to build your own Docker-like infrastructure that only you were using

[tonyarkles]

Solaris Zones too. Absolute magic, many years before Docker and friends.