OpenVZ is dead (RIP) so it's lxc or micro containers (Docker has been ported to arm - although I haven't tested it).
The isoloation issues still exist, although lots of workloads don't need to be privileged. In those cases isolation is a non issue.
If you want isolation, you'll need to use something else, like qemu. It should run ok on arm, although without kvm you'll take a performance hit (software virtualization on a low speed machine...). Apparently rpi 2 onwards supports kvm in theory, but I think it involves some hackery.