fix(rds): readers not always be created after the writer

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

@@ -772,6 +772,8 @@ abstract class DatabaseClusterNew extends DatabaseClusterBase {
         subnetGroup: this.subnetGroup,
       });
       readers.push(clusterInstance);
+      // this makes sure the readers would always be created after the writer
+      clusterInstance.node.addDependency(writer);
 
       if (clusterInstance.tier < 2) {
         this.validateReaderInstance(writer, clusterInstance);

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

@@ -554,6 +554,42 @@ describe('cluster new api', () => {
         PromotionTier: 0,
       });
     });
+
+    test('readers always to be created after the writer', () => {
+      // GIVEN
+      const stack = testStack();
+      const vpc = new ec2.Vpc(stack, 'VPC');
+
+      // WHEN
+      new DatabaseCluster(stack, 'Database', {
+        engine: DatabaseClusterEngine.AURORA,
+        vpc,
+        vpcSubnets: vpc.selectSubnets({ subnetType: ec2.SubnetType.PUBLIC }),
+        writer: ClusterInstance.serverlessV2('writer'),
+        readers: [
+          ClusterInstance.serverlessV2('reader1', { instanceIdentifier: 'reader1' }),
+          ClusterInstance.serverlessV2('reader2', { instanceIdentifier: 'reader2' }),
+        ],
+      });
+
+      // THEN
+      const template = Template.fromStack(stack);
+      Array.isArray(template);
+      // reader1 should depend on the writer
+      template.hasResource('AWS::RDS::DBInstance', {
+        Properties: {
+          DBInstanceIdentifier: 'reader1',
+        },
+        DependsOn: Match.arrayWith(['Databasewriter2462CC03']),
+      });
+      // reader2 should depend on the writer
+      template.hasResource('AWS::RDS::DBInstance', {
+        Properties: {
+          DBInstanceIdentifier: 'reader2',
+        },
+        DependsOn: Match.arrayWith(['Databasewriter2462CC03']),
+      });
+    });
   });
 
   describe('instanceIdentifiers', () => {