This could be a much longer answer, but jails have nowhere near the level of control and isolation a &quot;real&quot; VM does even with the relatively recent additions of things like vimage and HRL&#x27;s.  Jails are awesome and I have used them for many years, but they are not a replacement for a hypervisor for many(most) use cases.<p>That said, when a young upstart was trying to sell me on Linux superiority and described Docker to me, all I could do was snicker.