Is it within the intended purpose of docker to serve live installations of Wordpress, OpenVPN, Django, or other apps, each in their own container, on a single droplet?
I'd like to combine some services on a single droplet but use docker to make them easy to spin off to their own droplet someday, not sure if this is the right use of Docker, thanks in advance.
Yes, this is right usage for Docker! =)
This is one of main purposes of Docker. You can look at Docker like a Virtual Machine, it's just much more lightweight, and is much easier to manage once you get into it.
You have many prebuilt images, that will let you run app very fast. You can also build your own images, there are many way to do it like Dockerfile or Docker Compose.
Helpful resources:
Docker image for WordPress.
Docker image for Django.
DigitalOcean - How To Install Wordpress and PhpMyAdmin with Docker Compose on Ubuntu 14.04.
DigitalOcean - How To Run OpenVPN in a Docker Container on Ubuntu 14.04.
DigitalOcean released new Docker tutorials, which are great and should help you to start with it. You can find all Docker tutorials under Docker tag.
If you get into any problem, feel free to ask anything, we'll try to help you.
