When using a data source for an AWS AMI, which value should be used for the ami argument in a resource?

When using a data source for an AWS AMI, which value should be used for the ami argument in a resource?

• A. aws_ami.ubuntu
• B. data.aws_ami.ubuntu
• C. aws_ami.ubuntu.id
• D. data.aws_ami.ubuntu.id

Answer: (D)

Data sources fetch real-world information so your Terraform configuration can reference up-to-date values. The ami argument on an AWS resource expects the AMI ID string. When you query an AMI with a data source like data.aws_ami.ubuntu, the id attribute contains the actual AMI ID. Therefore the correct reference is data.aws_ami.ubuntu.id, which yields a string you can pass to ami. Using the data source object itself would not match the expected type, and using a resource reference would point to a resource rather than the data retrieved from AWS.

Data sources fetch real-world information so your Terraform configuration can reference up-to-date values. The ami argument on an AWS resource expects the AMI ID string. When you query an AMI with a data source like data.aws_ami.ubuntu, the id attribute contains the actual AMI ID. Therefore the correct reference is data.aws_ami.ubuntu.id, which yields a string you can pass to ami. Using the data source object itself would not match the expected type, and using a resource reference would point to a resource rather than the data retrieved from AWS.