What does terraform plan do and why should you always review it before applying?

terraform plan creates an execution plan — a preview of what Terraform will do before it actually makes changes. It shows additions, modifications, and destructions.

Always review the plan because:

• It may show unexpected destructions (e.g., a stateful database being replaced instead of modified)
• It catches misconfiguration before real infrastructure is affected
• In a CI/CD pipeline, save the plan output and apply that exact plan in the next step to ensure consistency

terraform plan -out=tfplan
terraform apply tfplan