Infrastructure as Code, 2nd Edition

Chapter 6. Building Environments with Stacks

Chapter 5 described an infrastructure stack as a collection of infrastructure resources that you manage as a single unit. An environment is also a collection of infrastructure resources. So is a stack the same thing as an environment? This chapter explains that maybe it is, but maybe it isn’t.

An environment is a collection of software and infrastructure resources organized around a particular purpose, such as to support a testing phase, or to provide service in a geographical region. A stack, or set of stacks, is a means of defining and managing a collection of infrastructure resources. So you use a stack, or multiple stacks, to implement an environment. You might implement an environment as a single stack, or you might compose an environment from multiple stacks. You could even create several environments in one stack, although you shouldn’t.

What Environments Are All About

The concept of an environment is one of those things that we take for granted in IT. But we often mean slightly different things when we use the term in different contexts. In this book, an environment is a collection of operationally related infrastructure resources. That is, the resources in an environment support a particular activity, such as testing or running a system. Most often, multiple environments exist, each running an instance of the same system.

There are two typical use cases for having multiple environments running instances of the same system. ...