As mentioned already, our Docker Compose file is quite a simple example. Let's take a look at a more complex Docker Compose file and see how we can introduce building containers and multiple networks.
In the repository for this book, which is available at https://github.com/russmckendrick/mastering-docker/, you will find a folder in the chapter06 directory called example-voting-app. This is a fork of the voting application from the official Docker sample repository, which can be found at https://github.com/dockersamples/.
As you can see, the application is made up of five containers, two networks, and a single volume. Let's walk through the YAML file as there is a lot going on:
Our first container ...