Terraform often confuses new engineers for one simple reason.
The files look ordered.
But Terraform does not read them that way.
Instead, Terraform builds an internal dependency graph before it does anything else. That graph determines what can be created, what must wait, and what can run in parallel. This is why rearranging .tf files never fixes real problems.
The dependency graph Terraform builds is a Directed Acyclic Graph (DAG).
That phrase sounds academic, but it explains almost every “why did Terraform do that?” moment you will encounter.
In this lesson, we focus on:
- Why Terraform needs a graph at all
- What “directed” and “acyclic” mean in real infrastructure terms
- How dependencies are created through information and identity flow
- Why hard-coded values quietly break safety
- Why Terraform stops immediately when a loop exists
This is not about syntax or commands.
It is about understanding how Terraform thinks.
Once the graph clicks, planning output becomes predictable.
Apply behavior makes sense.
And debugging becomes calm instead of frustrating.
🎥 Watch the full lesson below to build the correct mental model.