Adding encryption to aws RDS AURORA postgresql pre create database

hi, Lay

First, You can't convert an unencrypted DB cluster to an encrypted one. You can check the detail on the document (https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/Overview.Encryption.html).

Also, you can't use blue/green deployment to convert cluster from unencrypted to encrypt. https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/blue-green-deployments-overview.html#blue-green-deployments-limitations-general

But, you can restore a new cluster from unencrypted snapshot.