I'm wondering if MacOS has the requisite system calls to have its own native containers, I imagine it does, Darwin being based on BSD. Are there any products that use that functionality?
Kind of but with limitations. You have chroot, which may or may not be secure, app sandbox which is quite powerful (but best used without chroot). No process namespaces or jails, very limited network isolation. No bind mounts. Overall very limited, you could do something but it woild be quite different.
Not sure how you get from Darwin being based on BSD to Darwin should be able to support something which heavily relies on Linux specific functionality to the point where even Freebsd having trouble https://wiki.freebsd.org/Docker
Sure with enough changes MacOS could support it, but then with enough changes to anything, so that is not really a sensible measure.
The question wasn't about running docker on *BSD or macOS, but rather running some form of native container. Native containers don't rely on linux, they rely on the kernel having some form of containerization primitive.
FreeBSD has jails, which are a native type of container on freebsd.
However, BSD operating systems are really different from each other. OpenBSD doesn't have jails or anything too like containers, and macOS does have sandboxes (which are kinda like a container in some way), but no proper containers.
Docker isn't really related to the question of whether a native container solution exists on non-linux platforms.
