Some of my colleagues at Pivotal are running iOS builds with it. That is, they're running builds on a Mac which has an iOS device plugged into it. The workers are run using Houdini, which is a container management daemon that, er doesn't use containers:
https://github.com/vito/houdini
There's a blog post by someone else at Pivotal, although the details are probably a bit out of date by now:
https://blog.pivotal.io/labs/tech-talks/on-device-open-sourc...