I still think that Solaris zones are / were a superior technology. Sadly it died with the demise of Solaris as an operating system. Still in use in some "must have enterprise" types of companies.
I would not run anything serious on docker (definitely not yet) if I would not be heavily invested in understanding and contributing to the technology (docker codebase + related).
Docker is a nice to have but absolutely abstracts too much and takes control from you. I am wondering what people like Brendand Gregg think about docker.
Solaris within Oracle is as good as dead from the latest reports. However, Illumos is a Solaris descendant that is very much alive. It has all the good systems stuff that came out of Sun (zones, ZFS, DTrace) and is backed by Joyent (now part of Samsung).
There's also FreeBSD jails that can be used to contain applications. I'm not sure about the timeline, but I think jails came first. Sun engineers wanted to achieve the same so they ported the same technology over to Solaris.
