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.
