docdb: Cannot delete the subnet group because at least one database cluster

[rantoniuk]

Describe the bug

Stack deployed from:

export class MongoDbStack extends cdk.Stack {
  constructor(scope: Construct, id: string, props: MongoStackProps) {
    super(scope, id, props);

    new docdb.DatabaseCluster(this, 'MongoCluster', {
      dbClusterName: 'MongoCluster',
      masterUser: {
        username: `${props.envv.db.mongo.dbUserName}`,
        excludeCharacters: "\"@/:!^;,~%+&()?<>*[]{}_-.#?'`\\|",
      },
      instanceType: ec2.InstanceType.of(props.envv.db.mongo.instance, props.envv.db.mongo.instanceSize),
      // instances: 1,
      vpc: props.vpc,
      securityGroup: props.dbSecurityGroup,
      storageEncrypted: true,
      deletionProtection: true,
      removalPolicy: cdk.RemovalPolicy.RETAIN,
      vpcSubnets: { subnetType: ec2.SubnetType.PRIVATE_ISOLATED },
    });

  }
}

Now, there are two bugs here:

• instances are supposed to be by default == 1 , but when instances: 1 is commented out, the cluster is created without any instances
• when I try to destroy the stack, I get:

6:47:47 PM | DELETE_FAILED        | AWS::DocDB::DBSubnetGroup                   | MongoClusterSubnets57E68960
Got InvalidDBInstanceStateException with error: Cannot delete the subnet group 'mongoclustersubnets57e68960-jxuv00nfliql' because at least one database cluster: mongocluster is still using
it.

Expected Behavior

as above.

Current Behavior

as above.

Reproduction Steps

As above.

Possible Solution

No response

Additional Information/Context

No response

CDK CLI Version

2.128.0 (build d995261)

Framework Version

No response

Node.js Version

v18.18.2

OS

MacOS

Language

TypeScript

Language Version

No response

Other information

No response

[tim-finnigan]

It looks like the second issue is a duplicate of a one opened last week: #29054. There is already a PR up to fix it: #29059. Regarding the first issue - it looks like the logic here doesn't allow for deploying less than one instance.

[rantoniuk]

Well, maybe the logic doesn't allow, but Cloudformation apparently does. My AWS Console shows 0/0 instances in that cluster ;-)

[github-actions]

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