FreeBSD has had jails since version 4 (~year 2000), fwiw.
Much of the technology was there, but Docker was able to achieve a critical mass, with streamlined workflows. Perhaps as much a social phenomenon as a technical one?
Much of the technology was there, but Docker was able to achieve a critical mass, with streamlined workflows. Perhaps as much a social phenomenon as a technical one?
They're way closer to the usual "Unix" tool feel too. Docker feels 100% like an attempt to get rich by engineering a monolith rather than be a few helper C tools. Docker was so annoying to learn.
Fortunately with the end of ZIRP and SaaS deflation (in real user terms, not fake investment to project we still live in the 2010s heyday), software engineers are focused on engineering more than hype generation. Am excited about energy based models, capture of electromagnetic geometry of the machine as it runs programs.
60s style lexical state management systems dragged forward in time because of social momentum have little to do with engineering. Are hardly high tech in 2025.
The big pain with jails for me was the tooling. There was a number of non-trivial steps needed to get a jail that could host a networked service, with a lot that could go wrong along the way.
Sure a proper sysadmin would learn and internalize these steps, but as someone who just used it now and again it was a pain.
Way down the line things like iocage came along, but it was fragile and not reliable when I tried it, leading to jails in weird states and such.
So I gave up and moved to Linux so I could use Docker.
Super easy to spin up a new service, and fairly self-documenting as you just configure everything in a script or compose file so much less to remember.
Initially in a VM on Bhyve, now on bare metal.
It feels a bit sad though, as jails had some nice capabilities due to the extra isolation.
The effort to introduce the concepts to the mainstream can’t be understated. It seems mundane now but it took a lot of grassroots effort and marketing to hit that critical mass.