FreeBSD, linux container, mount lin* filesystems instead of native BSD filesystems

[gizahNL]

What is the problem you're trying to solve
FreeBSD has the "linuxulator" which allows running Linux ELF binaries by using syscall redirection. This, in theory, should allow running Linux containers on FreeBSD, provided they do not depend on syscalls not provided by the FreeBSD linuxulator.
Unfortunately Linux binaries depend on a bit more than just syscall redirection, also some emulated filesystems need to be mounted for the best compatibility (see: https://wiki.freebsd.org/LinuxJails) for a list with mount options.

Describe the solution you'd like
Ideally containerd should recognize that it's running on FreeBSD, but the container is Linux based and modify the mount points accordingly.

Additional context
If someone could point me to what parts of containerd would have responsibility in creating the list of FS's to mount and have ideally access to the containers platform definition I might be able to create a POC.

[gizahNL]

Would be fixed with PR #5480

[emaste]

#7000 is now merged, should this be closed?

[icodeforyou-dot-net]

Do I get this correctly that via #7000 we can now actually run Linux containers on FreeBSD via the linux compatibility layer? I was researching this topic when I found this issue here. I haven't found any documentation of this so far.

[kzys]

@samuelkarp Can we close this one now?

[samuelkarp]

@kzys I think so. Closing.