[coder543]

> Sure, but usual practice with containers is to put each thing in its own, unless they are very tightly coupled. Web-app with a SQL database and a memory cache? Three containers. You can do otherwise, but that's typical. Usually each container ends up with one main, important running process, and not much else.

I agree, but... getting all the application dependencies in there is more than just getting a single binary in there. If it's just a single-binary Go program, then a Jail works just fine, but it's not that simple for a Ruby application. I'm definitely not talking about databases running in the same container as the application. That's where Kubernetes and docker-compose come in for multi-container orchestration, which are things that FreeBSD Jails don't have as far as I know.

> These are exactly the kinds of things I was thinking of when I noted that the OS itself has been seriously diminished in importance

Yes, but... these are all the things that FreeBSD doesn't offer. These are the real reasons that people don't talk about FreeBSD Jails in the same breath as Docker. The Docker container itself (or the FreeBSD Jail) as a unit of isolation is the least interesting part of the ecosystem. All of the developer tools, orchestration tools, and prebuilt images are what make the Docker universe so interesting, and make FreeBSD Jails... less interesting.

You said you were confused why Jails don't have more mindshare. It has absolutely nothing to do with people being able to invent useless tools and write blog posts about them, and it has absolutely nothing to do with FreeBSD Jails being too well documented. You kind of implied those were the best explanations you could come up with. Those are not the problems at all, and it seems disingenuous to me to say you think those are the problems unless you really didn't know the things I mentioned in my first reply.

[handrous]

My personal favorite thing about Docker, and the part I'd most miss if I switched to Jails (which I'm fairly confident could meet my needs with some fairly simple scripts and aliases that wouldn't take me long to arrive at, which is why I think there's so much less of an "ecosystem" there, even a nascent and under-developed one) is the way it forces projects to un-fuck their configuration.

500-line config, much of which few people ever care about, with all kinds of ill-conceived nesting? Better put the ~20 options that 99% of users ever touch in environment variables, and document them. Weird state garbage that's not captured in your config-on-disk? Better figure it out and get it into env vars, and have your startup script use those to transparently manage whatever bad decisions you made re: state in the past. Shit files all over the system? Better get that sorted out so people can handle persistence with at the very most three total mounts—and oh, gee, look, now your simple example docker-compose also serves to document where exactly you store files. And so on.

(my second-favorite thing is that it's a de-facto cross-distro package manager with very up-to-date packages that are trivial to completely and cleanly uninstall)

[oarsinsync]

FreeBSD introduced Jails in 1999.

I used my first Jail in 2001.

Docker was started over a decade later in 2013.

It’s reasonable to be confused why Jails lacks the mindshare. “Because it lacks all these other over-the-top features that we need” might be reasonable in response, except that Docker didn’t have any of these things on day 0 either.

Jails had a 14 year head start, Docker reinvents the wheel, and nor particularly well at first. Why did it succeed more than Jails did? It wasn’t because of the piss-poor native Mac support.

[tptacek]

It seems pretty obvious that the big thing here is that most people ship apps on Linux, not on FreeBSD.