Even though they are outside the topic of this book, virtual machines are a powerful tool and a first-class citizen in a good development environment. They provide dynamic and easy-to-use resources in isolated systems so they can be used and dropped at the time we need them. This helps developers to focus on their tasks instead of wasting their time creating or installing required services from scratch. This is the reason why virtual machines have found room in here. We want to take advantage of them to keep you focused on the code.

In order to have the same environment no matter the OS you're using, we'll be creating virtual machines with Vagrant and deploying required applications with Docker. We chose Ubuntu as a base operating system in our examples, just because it is a popular, commonly used Unix-like distribution. Most of these technologies are platform-independent, but occasionally you won't be able to follow the instructions found here because you might be using some other operating system. In that case, your task is to find what the differences are between Ubuntu and your operating system and act accordingly.