What is the purpose of the terraform apply command?

The terraform apply command is specifically designed to apply the changes necessary to bring the infrastructure to the desired state as defined in the Terraform configuration files. When this command is executed, Terraform evaluates the current state of the infrastructure and compares it against the desired state outlined in the configuration. It then generates an execution plan, which details the actions required—such as creating, modifying, or destroying resources—to align the actual state with the desired configuration. After reviewing the plan, the user can confirm and proceed, at which point Terraform takes the necessary actions to make those changes in the infrastructure.

This process is fundamental to Terraform's functionality, enabling infrastructure as code, where infrastructure resources can be managed and updated efficiently. It facilitates version control and collaborative workflows, making it easier to maintain complex environments and automate deployments.