Is there any way to grant RDSADMIN USER privileges to a user?

Question

GRANT APPLICATION_PASSWORD_ADMIN,BACKUP_ADMIN,FLUSH_OPTIMIZER_COSTS,FLUSH_STATUS,FLUSH_TABLES,FLUSH_USER_RESOURCES,
INNODB_REDO_LOG_ARCHIVE,PASSWORDLESS_USER_ADMIN,SHOW_ROUTINE

I want to grant these to another user, but this caused error and it says

[ERROR 1227 (42000): Access denied; you need (at least one of) the RDSADMIN USER privilege(s) for this operation]

Is there any way?

Answer 1

No.

The RDSADMIN user is how AWS manages the Amazon RDS database.

From MySQL security on Amazon RDS - Amazon Relational Database Service:

To provide management services for each DB instance, the rdsadmin user is created when the DB instance is created. Attempting to drop, rename, change the password, or change privileges for the rdsadmin account will result in an error.

Some (or all) of those are restricted permissions. Some might be granted to the 'Master' user of the database, but you are not able to assign them to other users.