Most of the examples we have looked at so far have been static in nature. This is fine for the simplest playbook examples, but in many cases, it is desirable to be able to either store values or define them easily in a central place, rather than having to go hunting through a playbook (and tree of roles) for a specific hardcoded value. As in other languages, it is also desirable to capture values somehow, for reuse later.
There are many different types of variables in Ansible, and it is important to know that they have a strict order of precedence. Although we won't encounter this much in this book, it is important to be aware of this, as you might otherwise receive unexpected results from your variables.
