I have used them maybe in a weird way. It might be a really stupid way too, but it made my life way simpler. I had some legacy code that was being repurposed a

I have used them maybe in a weird way. It might be a really stupid way too, but it made my life way simpler. I had some legacy code that was being repurposed and I couldn't touch the production environment, not even to build again. I could have tried building new VMs, but in the end I defined the build process with a Dockerfile. Environment variables, compilers, external dependencies, all of it done when you ran "docker build". There was a small script to orchestrate that and copy out the results too. The build environment was consistent, it was easy to tweak, and I could build for centos 6, centos 7, and suse 12 on any machines. That let me use my test box to implement and test any environment changes before it moved to production. It also let the primary developers build their own versions of it whenever they had made a change that needed testing. It's not at all like any of the use-cases I read about, but it made my life so much easier.