Amazon web services 如何在CDK中创建Aurora无服务器数据库

我正在尝试建立一个aurora无服务器数据库。在控制台中，它很简单，我只使用默认的子网组，一切都很好

但是，当我使用cdk时，会出现错误“Aurora Serverless不支持子网位于同一可用性区域的DB子网组。请选择子网位于不同可用性区域的DB子网组。”。我已经尝试过故障排除，但我真的不明白为什么它失败了，我想它使用的默认子网与我手动操作时使用的相同（而且它工作正常）？那么，为什么在使用cdk时突然出现了所有错误

const auroraDatabaseCluster = new rds.ServerlessCluster(this, 'Database', {
    engine: rds.DatabaseClusterEngine.AURORA_POSTGRESQL,
    credentials: rds.Credentials.fromSecret(masterSecret),
    parameterGroup: clusterParameterGroup,
    defaultDatabaseName: databaseName,
    vpc: vpc,
    securityGroups: [databaseSecurityGroup],
    storageEncryptionKey: databaseKey,
    deletionProtection: false
  });

有人知道怎么回事吗

我还可以使用区域极光数据库让它工作

const auroraDatabaseCluster = new rds.DatabaseCluster(this, 'Database', {
    engine: rds.DatabaseClusterEngine.auroraPostgres({version: rds.AuroraPostgresEngineVersion.VER_11_8}),
    instances: 2, // TODO should be 2
    credentials: rds.Credentials.fromSecret(masterSecret),
    defaultDatabaseName: databaseName,
    port: endpointPort,
    storageEncrypted: true,
    storageEncryptionKey: databaseKey,
    deletionProtection: false, // TODO enable in prod
    parameterGroup: clusterParameterGroup,
    instanceProps: {
      instanceType: ec2.InstanceType.of(ec2.InstanceClass.BURSTABLE3, ec2.InstanceSize.MEDIUM),
      securityGroups: [databaseSecurityGroup],
      vpcSubnets: {
        subnetType: ec2.SubnetType.PRIVATE,
      },
      vpc,
    },
  });

---

我通过手动添加onePerAZ=true的DB securityGroup解决了这个问题

const subnetGroup = new rds.SubnetGroup(this, "subnetGroup", {
        description: `Subnetgroup for serverless postgres aurora databasa`,
        vpc: vpc,
        vpcSubnets: {onePerAz: true},
      })

  const auroraDatabaseCluster = new rds.ServerlessCluster(this, 'Database', {
    engine: rds.DatabaseClusterEngine.AURORA_POSTGRESQL,
    credentials: rds.Credentials.fromSecret(masterSecret),
    parameterGroup: clusterParameterGroup,
    defaultDatabaseName: databaseName,
    vpc: vpc,
    subnetGroup: subnetGroup,
    securityGroups: [databaseSecurityGroup],
    storageEncryptionKey: databaseKey,
    deletionProtection: false
  });