Summary
In this chapter, we introduced Terraform modules. Modules are at the heart of IaC as they are the key component to reusing code quickly and efficiently. The structure of a module follows the same structure we have been using to write Terraform code. We declare variables in variables.tf, place our main code in main.tf, and use the outputs.tf file to expose information to the root module.
However, it’s important to use modules wisely. A module should not be a thin wrapper to existing resource definitions. A well-designed module adds value by providing a layer of abstraction. This can include provisioning multiple resources in a single module and adding organizational patterns and policies. In our albeit simple example, we provisioned not only a server but also a static IP address, and we added a layer of abstraction by providing a mapping of simple server size to instance types.
When you start writing Terraform code, always think about modules. Local modules help...
