RDS Serverless V2 via CDK

[amarflybot]

Hi Team, Could someone please guide me creating Serverless V2 Via cdk.

I tried to create with ServerlessCluster CDK, Its throwing error because V2 needs a clsuter and instance separately.
Then I tried with DatabaseCluster CDK, but it did not had the scalling Option.

Tried with below CDK code:

        const databaseCluster = new rds.DatabaseCluster(this, 'DatabaseCluster', {
            clusterIdentifier: `test-db-cluster`,
            engine: rds.DatabaseClusterEngine.auroraPostgres({
                version: AuroraPostgresEngineVersion.VER_13_6
            }),
            parameterGroup: rds.ParameterGroup.fromParameterGroupName(
                this,
                'parametergroup',
                'default.aurora-postgresql13',
            ),
            credentials: rds.Credentials.fromSecret(secret),
            instanceProps: {
                instanceType: new InstanceType('serverless'),
                //instanceType: ec2.InstanceType.of(ec2.InstanceClass.BURSTABLE2, ec2.InstanceSize.SMALL),
                vpc,
                vpcSubnets: {
                    subnets: [
                        ec2.Subnet.fromSubnetAttributes(this, 'db-subnet1', {
                            subnetId: config.subnetIds[0],
                            availabilityZone: config.availabilityZones[0],
                        }),

                        ec2.Subnet.fromSubnetAttributes(this, 'db-subnet2', {
                            subnetId: config.subnetIds[1],
                            availabilityZone: config.availabilityZones[1],
                        }),
                    ],
                },
                securityGroups: [securityGroup],
            },
        });

But this did not help, giving the below error:

Set the Serverless v2 scaling configuration on the parent DB cluster before creating a Serverless v2 DB instance.

[skinny85]

What part is the RDS Aurora v2 difference in the code above?

It looks exactly like a v1 Aurora Cluster to me.

[amarflybot]

@skinny85 , This is where I have reached till now, Please have a look.

const cfnDBCluster = new rds.CfnDBCluster(this, "DBServerlessCluster", {
    engine: "aurora-postgresql",
    availabilityZones: config.availabilityZones,
    dbClusterIdentifier: `db-cluster-${config.environment}`,
    dbClusterParameterGroupName: "default.aurora-postgresql13",
    dbSubnetGroupName: rds.SubnetGroup.fromSubnetGroupName(
      this,
      "SubnetGroup",
      ssm.StringParameter.valueForStringParameter(
        this,
        "db-subnet-group-name"
      )
    ).subnetGroupName,
    deletionProtection: false,
    enableHttpEndpoint: false,
    engineMode: "provisioned",
    engineVersion: "13.6",
    kmsKeyId: encryptionKey.keyId,
    masterUsername: secret.secretValueFromJson("username").toString(),
    masterUserPassword: secret.secretValueFromJson("password").toString(),
    storageEncrypted: true,
    useLatestRestorableTime: false,
    vpcSecurityGroupIds: [securityGroup.securityGroupId],
  });

  const cfnDBInstance = new rds.CfnDBInstance(this, "MyCfnDBInstance", {
    dbInstanceClass: "db.serverless",
    dbClusterIdentifier: cfnDBCluster.dbClusterIdentifier,
    dbInstanceIdentifier: `db-instance-${config.environment}`,
    storageEncrypted: true,
    dbParameterGroupName: "default.aurora-postgresql13",
    dbSubnetGroupName: rds.SubnetGroup.fromSubnetGroupName(
        this,
        "SubnetGroupInstance",
        ssm.StringParameter.valueForStringParameter(
          this,
          getPath("db-subnet-group-name", config.environment)
        )
      ).subnetGroupName,
    engine: "aurora-postgresql",
    engineVersion: "13.6"
  });

  const modifyDBCluster = new cr.AwsCustomResource(this, 'modify-db-cluster', {
    onUpdate: {
      physicalResourceId: cr.PhysicalResourceId.of(cfnDBCluster.dbClusterIdentifier),
      service: 'RDS',
      action: 'modifyDBCluster',
      parameters: {
        DBClusterIdentifier: cfnDBCluster.dbClusterIdentifier,
        ServerlessV2ScalingConfiguration: {
            MaxCapacity: '16',
            MinCapacity: '1'
        }
      }
    },
    policy: cr.AwsCustomResourcePolicy.fromSdkCalls({
        resources: cr.AwsCustomResourcePolicy.ANY_RESOURCE,
      }),
  });

  cfnDBInstance.addDependsOn(cfnDBCluster);

modifyDBCluster step is not waiting for cfnDBCluster creation to complete.

[skinny85]

You probably need a dependency between modifyDBCluster and cfnDBCluster. You can do it using modifyDBCluster.node.addDependency(cfnDBCluster).

[amarflybot]

Sorry for not updating this, I tried it. Did not work. modifyDBCluster step did not run at all.

[skinny85]

You probably need to change it somehow to make it trigger again (since CloudFormation saw no changes to the resource, it didn't invoke your handler again).

[amarflybot]

I created an intermediate ssm parameter, It works now. Thanks a lot @skinny85

[github-actions[bot]]

Hello! Reopening this discussion to make it searchable.