RDS DatabaseClusterEngine.AURORA_MYSQL missing Defaults

[konstantinj]

❓ General Issue

It's hard to get a working Aurora/Mysql stack out of the box currently. It's a bit confusing that there is DatabaseClusterEngine.AURORA_MYSQL and DatabaseClusterEngine.AURORA while the latter one seems to be old version 5.6 and the other one is 5.7?

It seems it's still required to set engineVersion and parameterGroup and still I don't get a working stack with this code:

        const database = new DatabaseCluster(this, 'DatabaseCluster', {
            removalPolicy: RemovalPolicy.DESTROY,
            defaultDatabaseName: 'test',
            masterUser: {
                username: 'root',
                password: SecretValue.secretsManager(databaseSecret.secretArn),
            },
            instances: 1,
            engine: DatabaseClusterEngine.AURORA_MYSQL,
            parameterGroup: ParameterGroup.fromParameterGroupName(this, 'ParameterGroup', 'default.aurora-mysql5.7'),
            engineVersion: '5.7',
            port: 3306,
            instanceProps: {
                instanceType: InstanceType.of(InstanceClass.R5, InstanceSize.XLARGE8),
                vpc: vpc,
                vpcSubnets: {
                    subnetType: SubnetType.PRIVATE,
                },
                securityGroup: securityGroupDB,
            },
            backup: {
                preferredWindow: '00:00-01:00',
                retention: Duration.days(14),
            },
        })

Cloudformation error is:

RDS does not support creating a DB instance with the following combination: DBInstanceClass=db.r5.8xlarge, Engine=aurora-mysql, EngineVersion=5.7.12, LicenseModel=general-public-license

This might be due to Cloudformation being imprecise but I was expecting CDK to compensate this and set sensible defaults automatically.

Environment

• CDK CLI Version: 1.31.0
• Module Version: 1.31.0
• OS: OSX
• Language: Typescript

[nija-at]

@konstantinj - we apologize for this poor experience with RDS.

We have recognized the need that the RDS module needs a complete overhaul to fix this experience - #6713.

Upvotes on this issue will help us prioritize this.