Did you know Solaris zones at all before creating Docker?

Yes, of course. I was also an avid user of vserver and openvz on Linux, back when they required patching the kernel, and lxc didn't exist yet.

When we open sourced Docker, we had considerable experience running openvz in production, as well as migrating to lxc - a miserable experience in the early days because the paint was still so fresh. To my knowledge we were the very first production deployment of managed databases and multi-tenant application servers on lxc, back in 2010.

It's a common misconception that Docker was a naive reinvention of, or a thin wrapper around, pre-existing technology like solaris zones or lxc. In reality that is not the case. Those technologies were always intended as alternative forms of virtualization: a new way to slice up a machine. Docker was the first to use container and copy-on-write tech for the purpose of packaging and distributing applications, rather than provisioning machines. Before Docker, nobody would ever consider running a linux container or solaris zone on top of a VM: that would be nonsensical because they were considered to be at the same layer of the stack. Sun invented a lot of things, but they did not everything :)