Many engineers first encounter Terraform Stacks and assume they are another way to separate environments.
They solve a different problem.
Workspaces select different state instances. Stacks coordinate multiple infrastructure components and deployments.
This lesson introduces the hierarchy that makes Stacks easier to understand:
Stack → Components → Deployments → Inputs → Outputs → Dependency Graph
Using a simple network and application example, we follow how one component publishes data, how another component consumes it, and how Terraform automatically determines deployment order from those relationships.
Understanding this mental model helps explain why Terraform Stacks exist and what problem they were designed to solve.