This is specific to how AWS RDS specifies the ARN of the instance vs the ARN of the cluster.

When creating a Report in the console for RDS Aurora the cluster gets an ARN made up not of the cluster name, but of the cluster ID. The cluster ID is not obvious and must be searched in the AWS console or gotten via 2 API calls.
It would be great if the DoiT console could automatically include the cluster ARN whenever an instance ARN is given, since the storage and backup SKUs (at least) are under the cluster ID ARN instead of the instance ARN.

See for example this report:
https://console.doit.com/customers/yplJpzAvfOabLT98x41E/analytics/reports/n9MCbG19DoLYUM9lkN6S

To get the cluster ID from the Instance name you need to run 2 APIs
- describe-db-instances
- describe-db-clusters

for example:
```

Get DbClusterResourceId shown in Resource in Doit report from DB instance name

INSTANCE_NAME=reader1

CLUSTERID=$(aws rds describe-db-instances --db-instance-identifier $INSTANCENAME --query 'DBInstances[*].DBClusterIdentifier' --output text)

aws rds describe-db-clusters --db-cluster-identifier $CLUSTER_ID --query 'DBClusters[*].DbClusterResourceId' --output text
```
output:

cluster-G2AKAT4P3JCOQDWPH6CSFTQPKQ

With this information in the console, we could provide more "Insights" Eg “switch this cluster to I/O optimized”

See also the thread: https://doitintl.slack.com/archives/C010V5SE3T5/p1733133308618059