Common DBA Tasks for PostgreSQL

https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Appendix.PostgreSQL.CommonDBATasks.html

Amazon RDS for PostgreSQL Supports User Authentication with Kerberos and Microsoft Active Directory

https://aws.amazon.com/ru/about-aws/whats-new/2019/10/amazon-rds-for-postgresql-supports-user-authentication-with-kerberos-and-microsoft-active-directory/
Posted On: Oct 29, 2019

PostgreSQL versions 11.4, 10.9 and above are supported with Active Directory integration.
Требуется именно Microsoft Active Directory, и тогда в настройках датасета можно будет включить AD. Но тут есть нюанс, ИЛИ IAM, ИЛИ AD.