Building modules
Note
The code for this section is under the chap04/local-module directory in the GitHub repo of this book.
A module in Terraform serves the same purpose as a function in traditional programming languages. A module is a self-contained chunk of code that can be called repeatedly to create cloud infrastructure. Actually, we have already created modules. The Terraform configuration we wrote and executed is known as a root module. Modules called from other modules and stored locally are also known as child modules. So the root module can call a child module, which can call other modules.
The basic structure of a module is simple. By convention, we have three files: main.tf, which contains the main code, variables.tf, which defines the variables that need to be passed to the module, and outputs.tf, which contains the information passed back to the calling module. Do remember Terraform itself only cares about file extensions, here, .tf. Thus, as far as Terraform...
