CDK / Cloudformation versioning error creating a serverless cluster from a snapshot

Question

I'm attempting to make a db replica from a snapshot and am getting this error from CloudFormation

```
The engine version you requested for your restored DB cluster (13.12) is
earlier than the engine version of the DB cluster snapshot (13.13). (Service: Rds, Status Code: 400, Request
ID: asdf-asdf-asdf-asdf)
```

But as far as I can tell both the snapshot and the cluster being created from the snapshot have their engine versions set to `13.13`

CDK
```
const cluster = new ServerlessClusterFromSnapshot(this, 'replica-db-cluster', {
  snapshotIdentifier: snapshotArn,
  engine: DatabaseClusterEngine.auroraPostgres({
      version: AuroraPostgresEngineVersion.VER_13_13,
  }),
  copyTagsToSnapshot: false,
  vpc,
  vpcSubnets: {
    subnets: [privateDbSubnet1, privateDbSubnet2],
  },
})
```

Resulting CloudFormation template:
```
"replicadbcluster31639306": {
  "Type": "AWS::RDS::DBCluster",
  "Properties": {
    "CopyTagsToSnapshot": true,
    "DBClusterParameterGroupName": {
      "Ref": "replicadbparametergroup4CE24352"
    },
    "DBSubnetGroupName": {...},
    "Engine": "aurora-postgresql",
    "EngineMode": "serverless",
    "EngineVersion": "13.13",
    "SnapshotIdentifier": "arn:asdfasdfasdfasdf",
    "StorageEncrypted": true,
    "VpcSecurityGroupIds": [
      ...
    ]
  },
  "UpdateReplacePolicy": "Snapshot",
  "DeletionPolicy": "Snapshot",
  "Metadata": {
    "aws:cdk:path": "db-replica/replica-db-cluster/Resource"
  }
},
"replicadbparametergroup4CE24352": {
  "Type": "AWS::RDS::DBClusterParameterGroup",
  "Properties": {
    "Description": "Cluster parameter group for aurora-postgresql13",
    "Family": "aurora-postgresql13",
    "Parameters": {}
  },
  "Metadata": {
    "aws:cdk:path": "db-replica/replica-db-parameter-group/Resource"
  }
},
...
```

Snapshot:

![Enter image description here](/media/postImages/original/IMfR9-JC1iSV2aK8x4GHsJPQ)

Am I missing something when specifying a version? Why does CloudFormation say the cluster version is `13.12`?

Leo K · Accepted Answer

The CDK code seems to show you are creating an Aurora Serverless v1 cluster. I'm not an expert on the old version, but I think v1 has limited support for engine versions and 13.13 simply may not be supported.

I believe you should use the CDK construct aws_cdk.aws_rds.DatabaseClusterFromSnapshot instead and specify the appropriate options for a Serverless v2 deployment, if that's what you are intending (and which I could be mistaken about):
https://docs.aws.amazon.com/cdk/api/v2/python/aws_cdk.aws_rds/DatabaseClusterFromSnapshot.html

If the source system isn't a Serverless deployment at all, you would also have the broader range of engine versions available on a classical fixed-capacity Aurora cluster, without using the Serverless deployment model.

CDK / Cloudformation versioning error creating a serverless cluster from a snapshot

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