Terraform at Scale

Chapter 2. Input Variables

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It’s not possible to talk seriously about enterprise scale TF and not discuss input variables. Often, they will begin to be introduced early on in any project that is intended to be preserved. Typically, they are introduced to provide abstraction to TF projects, enabling reusability of configuration and easy updates to modifiable resource attributes.

Because this book is primarily about writing high quality, highly scalable TF projects, input variables are a natural starting place to begin the discussion. In this chapter, you will review the various ways in which variability may be introduced, focusing on the input variable component itself, and gain exposure to the other governance capabilities that input variables provide such as type constraints and validation{} blocks. By the end of this chapter, you will understand how to create high quality input variables that optimize the balance between expressiveness and control.

Variability of TF Configuration

As an Infrastructure ...