What is the impact of marking a variable as sensitive in Terraform?

Marking a variable as sensitive in Terraform has a significant impact on how that variable is handled throughout the lifecycle of a Terraform configuration. When a variable is designated as sensitive, it is specifically designed to prevent it from being displayed in Terraform's output, including the console or any log files, during commands like terraform plan or terraform apply. This is crucial for security reasons, as sensitive data often involves secrets, passwords, or tokens that should not be exposed publicly or logged, thereby helping to protect against unauthorized access.

However, even though marking a variable as sensitive prevents it from being printed in the outputs, it does not encrypt the variable or restrict its use in any comparisons. The variable remains usable within the configuration files and can be utilized wherever necessary, except in scenarios where the output is displayed. This distinction is important; it ensures security while maintaining functional flexibility in Terraform configurations.