There’s a geeky title for you! But it might help anyone Googling for those keywords…
Recent versions of Docker have many nice new facilities. Here’s a demo of how you can use the service-scaling to run multiple instances of your app back-end, and Nginx as a front-end proxy, while keeping track of them using the round-robin DNS facility built in to the Docker engine.
All demonstrated in a few lines of code on my laptop, using the new Docker for Mac.
Also available on YouTube.
Update, spring 2017: Do note that if you’re using Docker Swarm, you may want to adopt a more complex approach, perhaps based on Interlock.