So far, we know how to codify our infrastructure into Terraform templates of varying sizes. We know how to structure templates and how to split and reuse them with modules. More that this, we already figured out important concepts behind how Terraform works. But there is an important piece we almost didn't look at: configuration.

A template with only hardcoded data in it is a bad template. You can't reuse it in other projects without modifying it. You always have to update it by hand if some value changes. And you have to store a lot of information that doesn't really belong to the infrastructure template.

In this chapter, we will learn how to make Terraform templates more configurable. First, we will take a lookup variables and all the possible ways to use them. Then, we will learn how to use data resources to retrieve information from outside Terraform template. Finally, we will use built-in provider's capabilities to generate random data...