Providers and Resource Identity

Memory hook: Provider talks; state remembers.

Must remember

• A provider is a plugin implementing resource and data-source operations for an API. Terraform Core handles language evaluation and the dependency graph; it delegates API behavior to providers.
• required_providers declares source addresses and allowed versions. A provider block supplies a configuration such as region or endpoint. required_version constrains Terraform itself, not a provider.
• terraform init installs providers. Commit .terraform.lock.hcl so colleagues reuse selected provider versions and verified checksums. The lock file does not lock remote module versions.
• ~> 6.2 permits later 6.x releases; ~> 6.2.0 permits later 6.2.x patches. init -upgrade reselects versions within constraints, so review the lock-file diff.
• Multiple configurations of one provider use alias; select one with provider = aws.secondary. Child modules receive aliases through an explicit providers mapping and declare expected aliases.
• A Terraform resource address identifies a configured instance, such as module.web.aws_instance.node["blue"]. State connects that address to the remote object identifier. Renaming an address without a move declaration can look like delete-and-create.

Choose under exam pressure

Traps

• A provider alias is not a separate state file.
• An omitted default provider configuration can produce an empty default configuration, which may lack required settings.

Active recall

Sources

• language · providers · requirements
• language · providers · configuration
• language · files · dependency-lock