Infrastructure as Code, 3rd Edition

Chapter 8. Configuring Infrastructure Stack Instances

A Note for Early Release Readers

With Early Release ebooks, you get books in their earliest form—the author’s raw and unedited content as they write—so you can take advantage of these technologies long before the official release of these titles. This will be the 8th chapter of the final book. Please note that the GitHub repo will be made active later on. If you have comments about how we might improve the content and/or examples in this book, or if you notice missing material within this chapter, please reach out to the editor at [e-mail].

The previous chapter introduced the Reusable Stack pattern as a way to use infrastructure code to create multiple instances of the same infrastructure. The Reusable Stack is a core pattern for keeping infrastructure consistent across an estate. However, people often find it easier to create new infrastructure by copying or branching code to create a new project, the Snowflakes as Code antipattern. The most common reason people copy a stack project is because it’s the easiest way to customize different instances of a stack.

Different stack instances inevitably need to be customized. A simple example is a container cluster that needs fewer worker nodes in a development environment and more in a production environment. Copying and customizing a stack’s code is temptingly easy, especially if you need more complex differences than setting the size of a container cluster. But it ...