AWS::RDS::Cluster unable to upgrade major Engine Version with a Custom Parameter Group directly

[ZalmnS]

Name of the resource

AWS::RDS::DBCluster

Resource name

AWS::RDS::DBCluster

Description

When attempting a major engine version upgrade via CloudFormation for an AWS::RDS::Cluster that is using a Custom Parameter Group, where the Custom Parameter Group is set to the family of the destination Engine Version, we are met with the following error:

"The current DB instance parameter group <old Parameter Group> is custom. You must explicitly specify a new DB instance parameter group, either default or custom, for the engine version upgrade."

The only way to upgrade your Engine version DB Cluster via CloudFormation that is using a Custom Parameter Group is to perform 3 updates:

1. <Skip if you are using the default parameter group> First, update the Db Cluster Parameter Group to the Default Parameter Group for your specific Engine and Engine Version within your Stack. (Example, for aurora-postgres version 13: "default.aurora-postgresql13")
2. Second, update the DB Cluster Version, and Parameter group to the default parameter group for the destination Engine version.(Example, if I were upgrading from aurora-postgres version 13 to 14, I would need to set the Parameter group "default.aurora-postgresql14" within this update)
3. Third, in the last update, update your DB Cluster Parameter Group to the desired custom DB Cluster Parameter Group.

The idealized way of upgrading the DB Cluster Parameter Group would be:

Upgrade the Engine Version, and DB Cluster Parameter Group to the new Custom Parameter Group that is under the destination engine versions family.

Other Details

No response