What feature stops multiple admins from changing the Terraform state at the same time?

State locking is a critical feature in Terraform that prevents multiple administrators from making simultaneous changes to the Terraform state file. When a user starts a plan or apply operation, Terraform creates a lock on the state file, ensuring that no other operations can modify it until the current operation is completed. This mechanism helps avoid race conditions and potential conflicts that could arise if multiple changes were attempted at the same time.

For example, if two users were to apply changes to the infrastructure concurrently without state locking, they could inadvertently overwrite each other's changes, leading to an inconsistent state. By using state locking, Terraform ensures that the integrity of the state is maintained and that operations are executed in a controlled manner, which is essential for the reliability and stability of the infrastructure management process.

State versioning provides a history of changes, allowing users to roll back to previous states, but it does not prevent concurrent access to the state. State mirroring refers to duplicating the state across different backends for redundancy and availability but does not address the issue of simultaneous modifications. State auditing tracks changes made to the state for accountability but still allows for multiple changes without coordination. Thus, state locking is the key feature that safeguards against concurrent modifications, maintaining a single source of truth for the Terraform-managed infrastructure.