feat(rds): add ability to specify PreferredMaintenanceWindow to RDS cluster database instances

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

@@ -1371,6 +1371,7 @@ function legacyCreateInstances(cluster: DatabaseClusterNew, props: DatabaseClust
       autoMinorVersionUpgrade: instanceProps.autoMinorVersionUpgrade,
       allowMajorVersionUpgrade: instanceProps.allowMajorVersionUpgrade,
       deleteAutomatedBackups: instanceProps.deleteAutomatedBackups,
+      preferredMaintenanceWindow: instanceProps.preferredMaintenanceWindow,
     });
 
     // For instances that are part of a cluster:

packages/aws-cdk-lib/aws-rds/lib/props.ts

@@ -101,6 +101,17 @@ export interface InstanceProps {
    * @default - `true` if `vpcSubnets` is `subnetType: SubnetType.PUBLIC`, `false` otherwise
    */
   readonly publiclyAccessible?: boolean;
+
+  /**
+   * A preferred maintenance window day/time range. Should be specified as a range ddd:hh24:mi-ddd:hh24:mi (24H Clock UTC).
+   *
+   * Example: 'Sun:23:45-Mon:00:15'
+   *
+   * @default - 30-minute window selected at random from an 8-hour block of time for
+   * each AWS Region, occurring on a random day of the week.
+   * @see https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/USER_UpgradeDBInstance.Maintenance.html#Concepts.DBMaintenance
+   */
+  readonly preferredMaintenanceWindow?: string;
 }
 
 /**

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

@@ -209,6 +209,30 @@ describe('cluster new api', () => {
         ],
       });
     });
+
+    test('preferredMaintenanceWindow provided in InstanceProps', () => {
+      // GIVEN
+      const stack = testStack();
+      const vpc = new ec2.Vpc(stack, 'VPC');
+
+      const PREFERRED_MAINTENANCE_WINDOW: string = 'Sun:12:00-Sun:13:00';
+
+      // WHEN
+      new DatabaseCluster(stack, 'Database', {
+        engine: DatabaseClusterEngine.AURORA,
+        instanceProps: {
+          vpc: vpc,
+          preferredMaintenanceWindow: PREFERRED_MAINTENANCE_WINDOW,
+        },
+      });
+
+      // THEN
+      const template = Template.fromStack(stack);
+      // maintenance window is set
+      template.hasResourceProperties('AWS::RDS::DBInstance', Match.objectLike({
+        PreferredMaintenanceWindow: PREFERRED_MAINTENANCE_WINDOW,
+      }));
+    });
   });
 
   describe('migrate from instanceProps', () => {