Invalid configuration for blue/green configuration after promoting RDS green replica to standalone

Question

I played around with blue/green configuration in my dev environment and saw the UI allows to "Promote" the green staging replica to be standalone in the Actions menu.
So I decided to test it and after it finished I saw the Status on its parent row in the UI changed to "Invalid configuration".

Is that a bug or a feature?
Shouldn't RDS gray out the "Promote" action for the green environment as long as blue/green config exists?

rePost-User-9101779 · Answer

The PromoteReadReplicaDBCluster requests promote the green cluster as a standalone DB cluster, and it becomes no longer a read replica of the blue cluster. The replication breaks and as a result, Blue/Green Deployment shows an "INVALID_CONFIGURATION" status. Please use the Switchover process in Blue/Green Deployment to automatically perform the switchover without using the PromoteReadReplicaDBCluster request.

Since you might have seen in the B/G deployment that it uses the keyword "promote" to describe the processing of making a green deployment to replace a blue deployment, So you might have used the "Promote" button on the green cluster to do so. But it turns out that you should use the switch-over button.

Invalid configuration for blue/green configuration after promoting RDS green replica to standalone

Relevant content