There are only two ways you can scale an Amazon RDS database. You can modify the
instance size and you can also independently modify the storage type and capacity
You cannot use EC2 Auto Scaling or AWS (Application) Auto Scaling to automatically
scale your RDS database. EC2 Auto Scaling is involved with launching additional
instances (scale out) and this is not a method of scaling an RDS database and
application auto scaling is involved with automatically adjusting the assignment of
resources to the database which is not supported with RDS (you can do it with
DynamoDB)
You cannot use Elastic Load Balancing with RDS because there is only ever one master
database serving writes. If you want to scale reads you can implement Read
Replicas