A solutions architect is using an AWS CloudFormation template to deploy a three-tier web application.

Create an IAM role to read the DynamoDB tables. Associate the role with the application instances by referencing an instance profile.

Create an IAM role that has the required permissions to read and write from the DynamoDB tables. Add the role to the EC2 instance profile, and associate the instance profile with the application instances.

Use the parameter section in the AWS CloudFormation template to have the user input access and secret keys from an already-created IAM user that has the required permissions to read and write from the DynamoDB tables.

Create an IAM user in the AWS CloudFormation template that has the required permissions to read and write from the DynamoDB tables. Use the GetAtt function to retrieve the access and secret keys, and pass them to the application instances through the user data.