[kyptin]

Author here. Thanks for your comment. I figured this would be obvious to some.

Question: do you know of a good resource that describes docker in these terms, such that what I wrote about isn't surprising?

The official architecture page [1] doesn't illuminate this issue. To be fair, it isn't super relevant—so long as you run Linux, OS X, or Windows. When you run alternative OS's, though, it becomes pretty important.

[1] https://docs.docker.com/engine/understanding-docker/

[brudgers]

On Linux, Docker uses cgroups to isolate resources. Cgroups is a feature of the Linux kernel. Cgroups are almost ten years old.

Docker on FreeBSD utilizes the Linux compatibility layer. It was introduced in 2015. It is officially experimental.

https://wiki.freebsd.org/Docker

To me, none of this is obvious and my limited understanding has taken several years and many hours of podcast listening and technical reading. I still don't know squat.

[ibotty]

> Docker on FreeBSD utilizes the Linux compatibility layer. It was introduced in 2015. It is officially experimental.

Huh!? I remember running unmodified Linux binaries on FreeBSD (and other BSDs) in the late 90s. Maybe it was not suitable for most docker images and that started last year...

[brudgers]

Per the link, Docker [the subject of the thread] is experimental on FreeBSD.

[loukrazy]

All OSes that are not Linux are alternative OSes. Even Windows and OS X are running docker under virtualization one way or another (docker machine or the more recent virtualization shims).

[justincormack]

No, Docker can run Windows containers natively, although this has not been officially released quite yet it is a preview.