Infrastructure as Code, 3rd Edition

Chapter 8. Configuring Stack Deployment Instances

A Note for Early Release Readers

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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, a leading reason that people create unmaintainable Snowflakes as Code is the need to customize different instances of the infrastructure. A simple example is provisioning a container cluster with fewer worker nodes in a development environment than in a production environment.

Making a copy of a stack’s code and customizing it is temptingly easy, especially if you need more complex differences than setting the size of a container cluster. But it quickly leads to an unmaintainable mess of code and infrastructure, falling afoul of pretty much everything mentioned in Chapter 2.

Ensuring stacks are configurable helps to get the most ...