9. RDS インスタンスのマルチ AZ 配置化

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作成

• 作成者： moritalous
• 作成日： 2023/08/14

参照元：9. RDS インスタンスのマルチ AZ 配置化

マルチAZ配置は、CloudFormation同様、パラメーターのMultiAZをtrueに指定するだけです。

const rdsInstance = new rds.DatabaseInstance(this, 'RdsDBInstance', {
  vpc: vpc,
  engine: rds.DatabaseInstanceEngine.MYSQL,
  instanceType: ec2.InstanceType.of(ec2.InstanceClass.T2, ec2.InstanceSize.MICRO),
  
  databaseName: 'wordpress',
  
  vpcSubnets: {
    subnetType: ec2.SubnetType.PRIVATE_ISOLATED
  },
  
  multiAz: true
  
})

課題

RDSをマルチAZ配置に変更してください。

回答

bin/handson-cdk.ts

import * as cdk from "aws-cdk-lib";
import { Construct } from "constructs";
// import * as sqs from 'aws-cdk-lib/aws-sqs';
import * as ec2 from "aws-cdk-lib/aws-ec2";
import { Asset } from 'aws-cdk-lib/aws-s3-assets';
import * as rds from "aws-cdk-lib/aws-rds";
import * as elb from "aws-cdk-lib/aws-elasticloadbalancingv2";
import * as targets from 'aws-cdk-lib/aws-elasticloadbalancingv2-targets';

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

    // The code that defines your stack goes here

    // example resource
    // const queue = new sqs.Queue(this, 'HandsonCdkQueue', {
    //   visibilityTimeout: cdk.Duration.seconds(300)
    // });

    const vpc = new ec2.Vpc(this, "VPC", {
      natGateways: 0,
    });
    
    const instance = new ec2.Instance(this, 'EC2Instance', {
      vpc: vpc, 
      instanceType: ec2.InstanceType.of(ec2.InstanceClass.T2, ec2.InstanceSize.MICRO),
      machineImage: ec2.MachineImage.latestAmazonLinux2023(),

      vpcSubnets: {
        subnetType: ec2.SubnetType.PUBLIC
      },
      
      associatePublicIpAddress: true,
      
      instanceName: 'webserver1-user1',
      
    })

    instance.connections.allowFromAnyIpv4(ec2.Port.tcp(80))
    
    const asset = new Asset(this, 'Asset', {
      path: './asset/install_wordpress.sh'
    })
    
    const localPath = instance.userData.addS3DownloadCommand({
      bucket: asset.bucket,
      bucketKey: asset.s3ObjectKey
    })
    
    instance.userData.addExecuteFileCommand({
      filePath: localPath
    })
    
    asset.grantRead(instance.role)
    
    new cdk.CfnOutput(this, 'EC2PublicIP', {
      value: instance.instancePublicIp
    })

    const instance2 = new ec2.Instance(this, 'EC2Instance2', {
      vpc: vpc, 
      instanceType: ec2.InstanceType.of(ec2.InstanceClass.T2, ec2.InstanceSize.MICRO),
      machineImage: ec2.MachineImage.genericLinux({
        "ap-northeast-1": "ami-066ce4a60894618ce"
      }),

      vpcSubnets: {
        subnetType: ec2.SubnetType.PUBLIC
      },
      
      associatePublicIpAddress: true,
      
      instanceName: 'webserver2-user1',
      
    })
    
    const rdsInstance = new rds.DatabaseInstance(this, 'RdsDBInstance', {
      vpc: vpc,
      engine: rds.DatabaseInstanceEngine.MYSQL,
      instanceType: ec2.InstanceType.of(ec2.InstanceClass.T2, ec2.InstanceSize.MICRO),
      
      databaseName: 'wordpress',
      
      vpcSubnets: {
        subnetType: ec2.SubnetType.PRIVATE_ISOLATED
      },
      
      multiAz: true
      
    })
    
    rdsInstance.connections.allowDefaultPortFrom(instance)
    rdsInstance.connections.allowDefaultPortFrom(instance2)
    
    new cdk.CfnOutput(this, 'RDSDomainName', {
      value: rdsInstance.dbInstanceEndpointAddress
    })

    const loadBalancer = new elb.ApplicationLoadBalancer(this, 'ELB', {
      vpc: vpc,
      internetFacing: true,
    })

    const listener = loadBalancer.addListener('Listener', {
      port: 80
    })
    
    listener.addTargets('instance', {
      targets: [
        new targets.InstanceTarget(instance),
        new targets.InstanceTarget(instance2)
        ],
      port: 80,
      healthCheck: {
        path: '/wp-includes/images/blank.gif'
      }
    })
    
    instance.connections.allowFrom(loadBalancer, ec2.Port.tcp(80))
    instance2.connections.allowFrom(loadBalancer, ec2.Port.tcp(80))
    
    new cdk.CfnOutput(this, 'ELBDomainName', {
      value: loadBalancer.loadBalancerDnsName
    })

  }
}

まとめ

CloudFormationでは314行のYAMLを記述しました。CDKでは更に短くなり、128行のTypeScriptを記述（出力は864行のYAML）しました。
AWSのベストプラクティスに従えることやプログラム言語なので入力補完や型の提案も可能で開発効率が高いというメリットを体感できたと思います。