How do I restore RDS snapshot into a cloudformation?

Question

I want to restore an RDS instance from a snapshot and have it replace an instance in a cloudformation.

Let's say I have one EC2 instance connected to one RDS instance in a cloud formation and I want to restore the RDS instance from a snapshot.

Since an RDS snapshot can only be restored into a new RDS instance, and that new RDS instance needs the domain name of the old instance for my EC2 to reach it, I have to let go of the old RDS instance by renaming or deleting before creating the new restore, but then the new RDS is not in my cloud formation stack anymore and does not have the proper tags. Instead the tags are in my old throw away instance.

This causes some negative side effects, like problems deleting the cloudformation stack and issues with taking a proper inventory.

Anyone know how to put the new restored instance into my cloudformation again?

Answer 1

If you support downtime, you can proceed to:

1. append the 'DBSnapshotIdentifier' to your RDS cloudformation template
2. update your CFN stack which will recreate your RDS DB from the snapshot.
3. update your DNS/hosts entries since the new RDS instance will have a new address.