In Terraform, what does the 'terraform apply' command do?

The 'terraform apply' command is primarily used to apply changes to your infrastructure. When this command is executed, Terraform goes through the necessary steps to create, update, or delete resources as defined in the configuration files. It assesses the current state of the existing infrastructure, compares that state with the desired state outlined in the Terraform configuration, and then implements the necessary changes to achieve that desired state.

This process can involve creating new resources that are specified in the configuration, updating existing resources to match any modifications made, or even destroying resources that are no longer needed. It not only facilitates the creation of resources but also ensures that the infrastructure is aligned with the user's specifications across the board.

Understanding this function is critical for managing infrastructure as code effectively, as it allows users to implement their planned changes in a controlled manner while also providing an opportunity to review what will occur before the actual changes are performed. This ensures that users maintain control over their infrastructure and can prevent unintended consequences.