I&#x27;d say jails aren&#x27;t quite the same thing as Docker, they&#x27;re much closer to LXC. They&#x27;re really much closer to the &quot;chroot on steroids&quot; promise in that they&#x27;re basically lightweight virtual machines and are actually intended to be used as such. For instance jails usually run the full FreeBSD init system, while it&#x27;s [sort of] discouraged to do that with Docker.<p>On the other hand, I associate Docker more with the machinery it builds <i>on top of</i> containers. It&#x27;s got all the snapshotting and build&#x2F;distribution infrastructure. I think popular wisdom is also only to run a single process in a Docker container, whereas most people I&#x27;ve seen (myself included) treat jails a lot like a virtual machine.<p>Jails <i>are</i> really popular amongst FreeBSD users and I use them a lot myself, but FreeBSD is nowhere near as popular as Linux, so that&#x27;s one thing that held it back. Also, I think a big part of what has made Docker popular is all the deployment and distribution stuff on top of bare containers. The whole Docker philosophy of mostly immutable containers and microservices was what people wanted and FreeBSD jails aren&#x27;t really intended for that.