I am using RDS Postgresql db instance - v11.12 (not Aurora) and I cannot see option "Create Aurora read replica" as expected. Any config I need to update? I checked and see the region us-east-1 have that Aurora matching version with Postgres 11.12. But not sure why I cannot see replica option. Appreciate any help :)
This happened for me as well, I didn't see the obvious reason why I can't create an Aurora Read Replica, so I tried creating it via CLI and it worked:
To create cluster
aws rds create-db-cluster
--db-cluster-identifier <new cluster name>
--db-subnet-group-name <subnet: same as original db>
--vpc-security-group-ids <security group id: like sg-12345678>
--engine aurora-postgresql
--engine-version <same as original db>
--replication-source-identifier <arn of original db: like arn:aws:rds:eu-west-1:065414729932:db:my-database>
<if encrypted>
--storage-encrypted
--kms-key-id <kms key arn, like: arn:aws:kms:eu-west-1:065514443312:key/195dff9f-0ee3-1024-b61f-3e19e4523495>
and instance in it
aws rds create-db-instance
--db-cluster-identifier <cluster name>
--db-instance-class <desired instnace class>
--db-instance-identifier <id of new instance>
--engine aurora-postgresql
and you will get Aurora Read Replica cluster (which will be read-only unless you promote it)
Commands are taken from official guide "Migrating data to Amazon Aurora"