The Joyent guys are running docker in smartos by so called "branded zones". They emulate the Linux Kernel ABI. This works surprisingly well, as they say. See: https://www.joyent.com/developers/videos/docker-and-the-futu...
The cool thing is, that they open sourced the SDC in November 2014.
http://www.openmirage.org/
http://osv.io/