FreeBSD has supported nesting of jails natively since version 8.0, which dates back to 2009. Looking at the jail(8) man page, there is an entire paragraph named Hierarchical Jails that explains the concept of jail hierarchy well. It’s one of the many gems of FreeBSD that, although not widely known or used, is, in my opinion, extremely useful.
BastilleBSD plays a central role in this article, and that’s a project I’ve been hearing a lot about recently. I feel like the various BSDs are currently hitting a stride, and there seems to be a lot of movement from Linux to BSD at the moment.
There is a nice course on BastilleBSD on Udemy.
I wonder if the Docker company would be interested to create a driver, that would really make a difference.
I just don’t know about this kind a move. I get the benefits, but there are some real draw backs to having some of your servers VM’s and others Jails. I’m assuming they have limited orchestration, and aren’t really scaling this solution. You can’t do live migration on Jails. But everyone’s situation is different. And the performance in a Jail vs vm might justify it in some cases. Plus its already strange to have that kind of diversification of operating systems, and likely presents its own set of challenges.