The high-availability feature is not a scaling solution for read-only scenarios; you cannot use a standby
replica to serve read traffic. To service read-only traffic, you should use a Read Replica. For more
information, see Working with PostgreSQL, MySQL, and MariaDB Read Replicas.
Reference: http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Concepts.MultiAZ.html

Explanation
When you want to automate deployment, the automatic choice is Cloudformation. Below is the excerpt from
AWS on cloudformation.
AWS Cloud Formation gives developers and systems administrators an easy way to create and manage a
collection of related AWS resources, provisioning updating them in an orderly and predictable fashion.
You can use AWS Cloud Formation's sample templates or create your own templates to describe the AWS
resources, and any associated dependencies or runtime parameters, required to run your application. You don't
need to figure out the order for provisioning AWS services or the subtleties of making those dependencies
work. Cloud Formation takes care of this for you. After the AWS resources are deployed, you can modify and
update them in a controlled and predictable way, in effect applying version control to your AWS infrastructure
the same way you do with your software
For more information on Cloud Formation, please visit the link:
* https://aws.amazon.com/cloudformation/
As per AWS,
"AWS Clastic Beanstalk provides support for running Amazon Relational Database Service (Amazon RDS)
instances in your Clastic Beanstalk environment. This works great for development and testing environments.
However, it isn't ideal for a production environment because it ties the lifecycle of the database instance to the
lifecycleofyour application's environment."
* https://docs.aws.a mazon.com/elasticbeanstalk/latesWdg/AW SHowTo.RDS.htm I

Note: If you need access to a host's localhost resolver, you must modify your DNS service on the host to listen on a non-localhost address that is reachable from within the container.
Note: The DNS server is always at 127.0.0.11.
Reference: https://docs.docker.com/engine/userguide/networking/configure-dns/