Many engineers first think of CI pipelines as a way to automate Terraform commands.
The deeper change is not automation.
Terraform running on a laptop uses a human identity. Terraform running in a CI pipeline uses a machine identity. The infrastructure code may remain unchanged, but the authorization boundary, execution process, and security model become different.
This lesson explores how commits trigger deployments, why shared state is required for ephemeral runners, how plan files create review checkpoints, and why modern pipelines increasingly rely on OIDC and temporary credentials instead of long-lived access keys.
Understanding this identity shift helps explain what CI actually changes—and what it does not.