4. Terraform Configuration (~22%)

This is the largest objective on the exam — the actual language you write. Everything here is built on the reconciliation model: you're describing desired state, and the constructs in this phase are how you describe it precisely, reuse it, and keep it safe. We'll move from the two block types that describe infrastructure (resource and data), through how blocks reference each other and form dependencies, to the tools that make configuration flexible (variables, outputs, locals, types, expressions, functions), and finally to the features 004 emphasizes for correctness and security: custom conditions, check blocks, and the newer ephemeral/write-only mechanisms for secrets.