CDK VPC Subnets with CIDR Addresses

network-stack.ts

import cdk = require('@aws-cdk/cdk');
import ec2 = require('@aws-cdk/aws-ec2');
import { SubnetType } from '@aws-cdk/aws-ec2';

const region = 'us-east';
const azA = `${region}-1a`;
const azB = `${region}-1b`;
const azC = `${region}-1c`;
const availabilityZones = [azA, azB, azC];
const publicCidrs = ['10.1.192.0/24', '10.1.194.0/24', '10.1.196.0/24']
const privateCidrs = ['10.1.193.0/24', '10.1.195.0/24', '10.1.197.0/24']

export class KhCdkInfrastructureStack extends cdk.Stack {
  constructor(scope: cdk.App, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    const vpc = new ec2.VpcNetwork(this, 'VPC', {
      maxAZs: 3,
      cidr: '10.1.192.0/18',
      enableDnsHostnames: true,
      enableDnsSupport: true,
      vpnGateway: true, // export bug: https://github.com/awslabs/aws-cdk/issues/2339 - will remove when fixed
      subnetConfiguration: [
        {
          cidrMask: 24,
          name: 'Public',
          subnetType: SubnetType.Public,
        },
        {
          cidrMask: 24,
          name: 'Private',
          subnetType: SubnetType.Private,
        }
      ],
    });

    const vpcResource = vpc.node.findChild('Resource') as ec2.CfnVPC;
    vpcResource.addPropertyOverride('Tags', {
      "Key" : 'Application',
      "Value" : 'HeyKind'
    });

    // Iterate the public subnets
    for (let [key, subnet] of vpc.publicSubnets.entries()) {
      const subnetSource = subnet.node.findChild('Subnet') as ec2.CfnSubnet;
      subnetSource.addPropertyOverride('CidrBlock', publicCidrs[key]);
      subnetSource.addPropertyOverride('AvailabilityZone', availabilityZones[key]);
    }

    // Iterate the private subnets
    for (let [key, subnet] of vpc.privateSubnets.entries()) {
      const subnetSource = subnet.node.findChild('Subnet') as ec2.CfnSubnet;
      subnetSource.addPropertyOverride('CidrBlock', privateCidrs[key]);
      subnetSource.addPropertyOverride('AvailabilityZone', availabilityZones[key]);
    }

    /* Outputs to be for App Stack.
    *  Will be imported with: cdk.Fn.importValue('VpcId')
    * @see {@link: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-importvalue.html}
    * @see {@link: https://awslabs.github.io/aws-cdk/refs/_aws-cdk_cdk.html?highlight=importvalue#@aws-cdk/cdk.Fn.importValue}
    * @see {@link: https://awslabs.github.io/aws-cdk/refs/_aws-cdk_aws-ec2.html#@aws-cdk/aws-ec2.VpcNetwork.importFromContext}
    */
    vpc.export();

  }
}