feat(rds): dual-stack mode support (#22596)

This PR adds dual-stack mode support to RDS instances and clusters.

### Aurora
- Working with a DB cluster in a VPC  
  https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/USER_VPC.WorkingWithRDSInstanceinaVPC.html
- CloudFormation AWS::RDS::DBCluster  
  https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-rds-dbcluster.html#cfn-rds-dbcluster-networktype

```ts
declare const vpc: ec2.Vpc; // VPC and subnets must have IPv6 CIDR blocks
const cluster = new rds.DatabaseCluster(this, 'Database', {
  engine: rds.DatabaseClusterEngine.auroraMysql({ version: rds.AuroraMysqlEngineVersion.VER_3_02_1 }),
  instanceProps: {
    vpc,
    publiclyAccessible: false,
  },
  networkType: rds.NetworkType.DUAL,
});
```

### RDS
- Working with a DB instance in a VPC  
  https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_VPC.WorkingWithRDSInstanceinaVPC.html
- CloudFormation AWS::RDS::DBInstance  
  https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-rds-dbinstance.html#cfn-rds-dbinstance-networktype

```ts
declare const vpc: ec2.Vpc; // VPC and subnets must have IPv6 CIDR blocks
const instance = new rds.DatabaseInstance(this, 'Instance', {
  engine: rds.DatabaseInstanceEngine.postgres({ version: rds.PostgresEngineVersion.VER_14_4 }),
  vpc,
  networkType: rds.NetworkType.DUAL,
  publiclyAccessible: false,
});
```

Note: CDK cannot check whether the specified VPC and subnets have actually IPv6 CIDR blocks because `ec2.IVpc` and `ec2.ISubnet` does not have ipv6 attributes. (cf. #19525)

----

### All Submissions:

* [x] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md)

### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [x] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/main/INTEGRATION_TESTS.md)?
	* [x] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-rds/README.md

@@ -50,6 +50,22 @@ By default, the master password will be generated and stored in AWS Secrets Mana
 Your cluster will be empty by default. To add a default database upon construction, specify the
 `defaultDatabaseName` attribute.
 
+To use dual-stack mode, specify `NetworkType.DUAL` on the `networkType` property:
+
+```ts
+declare const vpc: ec2.Vpc; // VPC and subnets must have IPv6 CIDR blocks
+const cluster = new rds.DatabaseCluster(this, 'Database', {
+  engine: rds.DatabaseClusterEngine.auroraMysql({ version: rds.AuroraMysqlEngineVersion.VER_3_02_1 }),
+  instanceProps: {
+    vpc,
+    publiclyAccessible: false,
+  },
+  networkType: rds.NetworkType.DUAL,
+});
+```
+
+For more information about dual-stack mode, see [Working with a DB cluster in a VPC](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/USER_VPC.WorkingWithRDSInstanceinaVPC.html).
+
 Use `DatabaseClusterFromSnapshot` to create a cluster from a snapshot:
 
 ```ts
@@ -129,6 +145,20 @@ const instance = new rds.DatabaseInstance(this, 'Instance', {
 });
 ```
 
+To use dual-stack mode, specify `NetworkType.DUAL` on the `networkType` property:
+
+```ts
+declare const vpc: ec2.Vpc; // VPC and subnets must have IPv6 CIDR blocks
+const instance = new rds.DatabaseInstance(this, 'Instance', {
+  engine: rds.DatabaseInstanceEngine.postgres({ version: rds.PostgresEngineVersion.VER_14_4 }),
+  vpc,
+  networkType: rds.NetworkType.DUAL,
+  publiclyAccessible: false,
+});
+```
+
+For more information about dual-stack mode, see [Working with a DB instance in a VPC](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_VPC.WorkingWithRDSInstanceinaVPC.html).
+
 Use `DatabaseInstanceFromSnapshot` and `DatabaseInstanceReadReplica` to create an instance from snapshot or
 a source database respectively:
 

packages/@aws-cdk/aws-rds/lib/cluster.ts

@@ -11,6 +11,7 @@ import { IClusterEngine } from './cluster-engine';
 import { DatabaseClusterAttributes, IDatabaseCluster } from './cluster-ref';
 import { DatabaseSecret } from './database-secret';
 import { Endpoint } from './endpoint';
+import { NetworkType } from './instance';
 import { IParameterGroup, ParameterGroup } from './parameter-group';
 import { applyDefaultRotationOptions, defaultDeletionProtection, renderCredentials, setupS3ImportExport, helperRemovalPolicy, renderUnless } from './private/util';
 import { BackupProps, Credentials, InstanceProps, PerformanceInsightRetention, RotationSingleUserOptions, RotationMultiUserOptions, SnapshotCredentials } from './props';
@@ -280,6 +281,13 @@ interface DatabaseClusterBaseProps {
    * @default - true
    */
   readonly copyTagsToSnapshot?: boolean;
+
+  /**
+   * The network type of the DB instance.
+   *
+   * @default - IPV4
+   */
+  readonly networkType?: NetworkType;
 }
 
 /**
@@ -481,6 +489,7 @@ abstract class DatabaseClusterNew extends DatabaseClusterBase {
       associatedRoles: clusterAssociatedRoles.length > 0 ? clusterAssociatedRoles : undefined,
       deletionProtection: defaultDeletionProtection(props.deletionProtection, props.removalPolicy),
       enableIamDatabaseAuthentication: props.iamAuthentication,
+      networkType: props.networkType,
       // Admin
       backtrackWindow: props.backtrackWindow?.toSeconds(),
       backupRetentionPeriod: props.backup?.retention?.toDays(),

packages/@aws-cdk/aws-rds/lib/instance.ts

@@ -274,6 +274,21 @@ export enum StorageType {
   IO1 = 'io1'
 }
 
+/**
+ * The network type of the DB instance.
+ */
+export enum NetworkType {
+  /**
+   * IPv4 only network type.
+   */
+  IPV4 = 'IPV4',
+
+  /**
+   * Dual-stack network type.
+   */
+  DUAL = 'DUAL'
+}
+
 /**
  * Construction properties for a DatabaseInstanceNew
  */
@@ -617,6 +632,13 @@ export interface DatabaseInstanceNewProps {
    * @default - `true` if `vpcSubnets` is `subnetType: SubnetType.PUBLIC`, `false` otherwise
    */
   readonly publiclyAccessible?: boolean;
+
+  /**
+   * The network type of the DB instance.
+   *
+   * @default - IPV4
+   */
+  readonly networkType?: NetworkType;
 }
 
 /**
@@ -759,6 +781,7 @@ abstract class DatabaseInstanceNew extends DatabaseInstanceBase implements IData
       maxAllocatedStorage: props.maxAllocatedStorage,
       domain: this.domainId,
       domainIamRoleName: this.domainRole?.roleName,
+      networkType: props.networkType,
     };
   }
 

packages/@aws-cdk/aws-rds/test/cluster-dual.integ.snapshot/aws-cdk-rds-cluster-dual-integ.assets.json

@@ -0,0 +1,19 @@
+{
+  "version": "21.0.0",
+  "files": {
+    "b5ff1147ce210b6a8be6120310d71e1a1bcb6c64b802b268e0b994bb80eb9ced": {
+      "source": {
+        "path": "aws-cdk-rds-cluster-dual-integ.template.json",
+        "packaging": "file"
+      },
+      "destinations": {
+        "current_account-current_region": {
+          "bucketName": "cdk-hnb659fds-assets-${AWS::AccountId}-${AWS::Region}",
+          "objectKey": "b5ff1147ce210b6a8be6120310d71e1a1bcb6c64b802b268e0b994bb80eb9ced.json",
+          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-file-publishing-role-${AWS::AccountId}-${AWS::Region}"
+        }
+      }
+    }
+  },
+  "dockerImages": {}
+}