[Bug]: Can't create RDS instances when default account CA isn't supported by engine

[williamlord-wise]

Terraform Core Version

1.9.5

AWS Provider Version

5.67.0

Affected Resource(s)

• aws_db_instance

Expected Behavior

It should be possible to create RDS instances with specific CAs that are specified with ca_cert_identifier , for example SQL Server with rds-ca-rsa4096-g1. It's not possible to create these instances current when the RDS default CA is overridden (https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_ModifyCertificates.html) to one that isn't supported by the engine and/or engine version, eg aws rds modify-certificates --certificate-identifier rds-ca-ecc384-g1.

Actual Behavior

The RDS instance can't be created because the RDS default CA is used, and then the ca_cert_identifier is applied afterwards https://github.com/hashicorp/terraform-provider-aws/blob/main/internal/service/rds/instance.go#L1802-L1806.

Relevant Error/Panic Output Snippet

> │ Error: creating RDS DB Instance (redacted): operation error RDS: CreateDBInstance, https response error StatusCode: 400, RequestID: c9daeb75-abbb-47be-8e53-afb637b875f0, api error InvalidParameterCombination: Version 15.00.4236.7.v1 for DB engine sqlserver-se doesn't support certificate rds-ca-ecc384-g1. Specify a different DB engine version or a different certificate.

Terraform Configuration Files

resource "aws_db_instance" "default" {
  engine             = "sqlserver-se"
  engine_version     = "15.00.4236.7.v1"
  ca_cert_identifier = "rds-ca-rsa4096-g1"
  ...
}

Steps to Reproduce

1. aws rds modify-certificates --certificate-identifier rds-ca-ecc384-g1
2. Apply Terraform

Debug Output

No response

Panic Output

No response

Important Factoids

No response

References

No response

Would you like to implement a fix?

None

[github-actions]

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