Which file format does Terraform primarily use to define infrastructure?

Terraform primarily uses HCL, or HashiCorp Configuration Language, to define infrastructure. HCL is a domain-specific language designed specifically for configuration files, making it both human-readable and machine-friendly. This syntax allows users to express their infrastructure as code more understandably and intuitively, which is particularly advantageous when working with complex configurations.

HCL's design emphasizes readability, with a focus on simplicity and clarity. The structure is hierarchical and supports comments, making it easier for users to manage and document their infrastructure setups. This feature is crucial for collaboration among team members, enhancing the code's maintainability and understanding.

In contrast, while JSON is a format that could technically be used with Terraform, it is less favored because it is more verbose and harder to read compared to HCL. YAML also offers readability benefits but is not used as the primary format for Terraform configurations. XML is even less common in this context, as it is more complex and not geared towards infrastructure as code scenarios. By utilizing HCL, Terraform provides a user-friendly approach to infrastructure management that aligns well with modern DevOps practices.