This is true but containers for mortals have lagged behind. Especially in management tools. There was cloudvz. Then cgmanage that couldn't run au pid 1 which has security concerns of its own. It wasn't until systemd that a small team could stand up containers with any type of scale. Basically everything before, more or less, took a proprietary config management setup.
We stood up containers, on very large scale, in a PaaS, with a very small team, in 2012 (long before systemd, or Docker for that matter, became a major force).
This was made possible by the work done by Serge Hallyn, Stephane Graber, and others at Canonical. They delivered LXC and its integration with AppArmor, which in turn stood on top of the cgroups/namespaces work that Google contributed to the kernel. Ubuntu 12.04 was the release where the ability to securely run containers at scale became available to mere mortals.
