Terraform does not deploy infrastructure from top to bottom.
Before any resources are created, Terraform builds a dependency graph during the planning phase. This graph determines the exact order in which infrastructure operations occur.
Every reference between resources becomes a graph edge. Terraform uses those edges to decide what must exist before another resource can be created.
The problem appears when dependencies are invisible to the planner.
Hard-coded IDs break Terraform’s ability to detect relationships. When that happens, the planner treats resources as independent. Terraform may then execute them in parallel, which can cause deployment failures that look random but are actually deterministic.
This lesson explains the planning pitfalls that occur when Terraform cannot see the dependency graph correctly, and how engineers restore order using explicit graph edges.
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