aws rds add-role-to-db-instance
Associates an Amazon Web Services Identity and Access Management (IAM) role with a DB instance. AWS CLI reference
3 options Its page in the AWS CLI reference
Options
--db-instance-identifierThe name of the DB instance to associate the IAM role with.--feature-nameThe name of the feature for the DB instance that the IAM role is to be associated with.--role-arnThe Amazon Resource Name (ARN) of the IAM role to associate with the DB instance, for example arn:aws:iam::123456789012:role/AccessRole.