AWS Elastic Beanstalk change RDS Endpoint

Question

How do I change the configured RDS endpoint of an AWS Elastic Beanstalk environment? E.g. after the RDS database was deleted or should be replaced with a new RDS database.

Answer 1

Update

The topic remains complex and the AWS Elastic Beanstalk (EB) documentation could still do a better job to clarify available options. The question has been about how to change an RDS endpoint, which seems to be read in two different ways:

1. One could interpret it about how to attach an existing externally managed RDS endpoint to an existing (not new!) EB environment - this is indeed not possible, rather one would need to resort to handling this scenario from within the app itself as e.g. outlined in section Using an Existing Amazon RDS DB Instance with Python within Using Amazon RDS with Python.
2. Rather, the OP asked about how to do that after the RDS database was deleted or should be replaced with a new RDS database, i.e. the RDS endpoint change is implied in the process of creating a new RDS database for an existing EB environment that already had one - this is indeed possible by means of the DBSnapshotIdentifier Option Value, which denotes The identifier for the DB snapshot to restore from. Once again the EB docs aren't exactly conclusive what this means, however, EB is using AWS CloudFormation under the hood, and the resp. entry for AWS::RDS::DBInstance - DBSnapshotIdentifier provides more details:
   

By specifying this property, you can create a DB instance from the specified DB snapshot. If the DBSnapshotIdentifier property is an empty string or the AWS::RDS::DBInstance declaration has no DBSnapshotIdentifier property, the database is created as a new database. If the property contains a value (other than empty string), AWS CloudFormation creates a database from the specified snapshot. If a snapshot with the specified name does not exist, the database creation fails and the stack rolls back.