How to recreate aws_rds_cluster in Terraform - amazon-web-services

Question

I am trying to create an encrypted version of my currently existing unencrypted aws_rds_cluster by updating my resource, I added:
kms_key_id = "mykmskey"
storage_encrypted = true
This is how my resource should look like:
resource "aws_rds_cluster" "my_rds_cluster" {
cluster_identifier = "${var.service_name}-rds-cluster"
database_name = var.db_name
master_username = var.db_username
master_password = random_password.db_password.result
engine = var.db_engine
engine_version = var.db_engine_version
kms_key_id = "mykmskey"
storage_encrypted = true
db_subnet_group_name = aws_db_subnet_group.fleet_service_db_subnet_group.name
vpc_security_group_ids = [aws_security_group.fleet_service_service_db_security_group.id]
skip_final_snapshot = true
backup_retention_period = var.environment != "prod" ? null : 7
# snapshot_identifier = "my-rds-instance-snapshot"
tags = { Name = "${var.service_name}-rds-cluster" }
}
The problem is that the original resource had delete_protection = true defined, which I also removed but, even though I removed it the original cluster cannot be deleted by any means in order for the new one to be created, neither through changes in Terraform, nor manually in AWS console, it just throws an error like:
error creating RDS cluster: DBClusterAlreadyExistsFault: DB Cluster already exists
Any ideas what to do in such cases?

Answer 1

To do that purely through Terraform, you would have to:
Remove deletion protection from the original Terraform resource
Run terraform apply, which will remove deletion protection from the actual resource in AWS
Make the modifications to the Terraform resource that will result in a delete or replace of the current resource
Run terraform apply again, during which time Terraform will now delete and/or replace the resource.
The key thing here being that you can't remove deleting protection at the same time you are actually deleting a resource, because Terraform isn't going to update an existing resource to modify an attribute before attempting to delete the resource.