I do exactly this; my build system does its builds for most platforms inside docker containers. (I haven't figured out how to do OSX builds inside a docker co

I do exactly this; my build system does its builds for most platforms inside docker containers. (I haven't figured out how to do OSX builds inside a docker container yet, but I'll figure it out eventually!) One of my targets is SteamOS (i.e.: Linux with a particular set of pre-installed shared libraries), and the preferred build environment to target that is inside a chroot. So my SteamOS builds get built inside a chroot inside a docker container. And that was surprisingly tricky to get working! There are some gotchas to overcome around how chroots handle symbolic links inside a docker container. But I've got it all working now. :) The big benefit is that host-OS-upgrades-for-security-purposes no longer upgrade my build's toolchain as a side-effect, potentially breaking or changing the performance of my build artifacts; it's fine to keep running ancient software inside that docker container that's just going to be wiped out in 10 minutes and never gets directly connected to the Internet anyway. And the docker image can be copied around to wherever I need it, if I need extra build workers or whatever. Once you've got the thing set up once, it's fantastic for scaling up your build server if you eventually want to do that.