chroot is a filesystem namespace, and containers are basically just that plus some other namespaces. Prior to containers getting really popular I was using debi

chroot is a filesystem namespace, and containers are basically just that plus some other namespaces. Prior to containers getting really popular I was using debian's schroot project and prior to that I was using solaris zones. There were other similar technologies prior to that but I wasn't really technical or even alive at the time. It's not new. Here's what's made them so popular lately IMO. Docker improved the usability by adding the container registry and adding some better tooling around running a container. Compare installing schroot plus configuring a new container plus running debootstrap plus potentially configuring lvm/btrfs/directory snapshotting to: docker run ubuntu:lts /bin/bash