3.1.2. terraform init
💡 First Principle: init is the command that makes a working directory operational — it gathers everything the directory depends on (backend, providers, modules) so that later commands have what they need; nothing else runs correctly until it has.
terraform init performs several setup tasks: it initializes the backend (where state lives), downloads and installs the providers named in required_providers, installs modules referenced in the configuration, and writes or verifies the dependency lock file. It's safe to run repeatedly — it's idempotent and won't touch real infrastructure.
Common situations that require a fresh init: cloning a new repo, adding or changing a provider version, adding a module, or changing the backend configuration. Useful flags include -upgrade (re-resolve provider/module versions to the newest allowed) and -reconfigure / -migrate-state (when changing backends).
⚠️ Exam Trap: terraform validate and terraform plan both require a successful init first, because they need the provider schemas that init downloads. A frequent trap is a scenario where validate "fails" simply because the directory was never initialized.
Reflection Question: Why must init run before validate, given that validate doesn't contact any real infrastructure?
