Comment by volkadav

If you mean an isolated linux instance _including a linux kernel_, that would be provided by a virtual machine running under the bhyve hypervisor on freebsd (https://docs.freebsd.org/en/books/handbook/virtualization/#v...). You probably could frankenkludge something like linux-userland-on-a-frebsd-kernel using jails but that certainly seems like the path less traveled, haha. :)