AWS CDK Overview

1. Overview

  • AWS CDK

    • Open source software development framework

    • Model and provision your cloud application resources

    • To resolve what issue?

      • provision cloud applications is challenging cause require
        • manual actions
        • custom scripts
        • maintain templates
        • domain specific languages
    • How does CDK resolve the issue?

      • Provides with high level component that pre-configure cloud resources with proven defaults
      • Provision your resources through AWS CloudFormation

1.1 Workflow

  • Creating an Amazon ECS service with AWS Fargate launch type
public class MyEcsConstructStack extends Stack {

    public MyEcsConstructStack(final Construct scope, final String id) {
        this(scope, id, null);
    }

    public MyEcsConstructStack(final Construct scope, final String id,
            StackProps props) {
        super(scope, id, props);

        Vpc vpc = Vpc.Builder.create(this, "MyVpc").maxAzs(3).build();

        Cluster cluster = Cluster.Builder.create(this, "MyCluster")
                .vpc(vpc).build();

        ApplicationLoadBalancedFargateService.Builder.create(this, "MyFargateService")
                .cluster(cluster)
                .cpu(512)
                .desiredCount(6)
                .taskImageOptions(
                       ApplicationLoadBalancedTaskImageOptions.builder()
                               .image(ContainerImage
                                       .fromRegistry("amazon/amazon-ecs-sample"))
                               .build()).memoryLimitMiB(2048)
                .publicLoadBalancer(true).build();
    }
}
  • Basic workflow

    • create the app from a template provided by the AWS CDK
    • add code to the app to create resources within stacks
    • build the app
    • synthesize one or more stacks in the app to create an AWS CloudFormation template
    • deploy one or more stacks to your AWS account
  • Benefits

    • Could use logic when defining infrastructure
    • Use object-oriented techniques to create a model of system
    • Define high level abstractions
  • Tools

    • CDK Toolkit

      • CLI for interacting with CDK apps
      • Enable developers to synthesize artifacts such as AWS CloudFormation templates, deploy stacks to development AWS accounts, and diff against a deployed stack to understand the impact of a code change
    • AWS Construct Library

      • contains constructs representing AWS resources
      • encapsulate the details of how to create resources for an Amazon or AWS service

1.1.1 Create and build the app

mkdir hello-cdk && cd hello-cdk
cdk init TEMPLATE --language LANGUAGE 

cdk init app --language java
// In your IDE, import it as maven project 

mvn compile 

cdk ls 

1.1.2 Add an Amazon S3 Bucket

// Add dependencies to pom.xml 
<dependency>
    <groupId>software.amazon.awscdk</groupId>
    <artifactId>s3</artifactId>
    <version>${cdk.version}</version>
</dependency>

Define an Amazon S3 bucket in the stack using L2 construct

package com.myorg;

import software.amazon.awscdk.core.*;
import software.amazon.awscdk.services.s3.Bucket;

public class HelloCdkStack extends Stack {
    public HelloCdkStack(final Construct scope, final String id) {
        this(scope, id, null);
    }

    public HelloCdkStack(final Construct scope, final String id, final StackProps props) {
        super(scope, id, props);

        Bucket.Builder.create(this, "MyFirstBucket")
            .versioned(true).build();
    }
}

1.1.3 Systhesize an AWS CloudFormation Template

cdk synth

1.1.4 Deploying the stack

cdk deploy

1.1.5 Modifying the stack

// after make your change 
cdk diff 
cdk deploy 

// Possibly destroy 
cdk destroy 
  • Synthesize before deploying

    2. Basic concepts

2.1 Constructs

2.1.1 Basics

  • Constructs

    • Basic building blocks

    • represents a cloud component, encapsulates everything AWS CloudFormation needs to create the component

    • [AWS Construct Library](https://docs.aws.amazon.com/cdk/api/latest/docs/aws-construct-library.html

    • defferent level of constructs

      • CFN Resources/ L1

        • directly represent all of the AWS resources that are available in AWS CloudFormation
        • named as CfnXyz, where xyz is name of the resource
        • When you use CFN resources, you must explicitly configure all resource properties, which requires a complete understanding of the details of the underlying AWS CloudFormation resource model
      • AWS Reousources/ L2 Constrcuts

        • higher level, intent based API
        • provide defaults, boilerplate, and glue logic you’d be writing with a CFN resource construct
        • Offer convenient defaults thus reduce the need for the detail of AWS resources
      • Patterns - higher level constructs

        • designed to help you complete common tasks in AWS, often involving multiple kinds of resources
// L1 Construct
CfnBucket bucket = CfnBucket.Builder.create(this, "MyBucket")
                        .bucketName("MyBucket")
                        .corsConfiguration(new CfnBucket.CorsConfigurationProperty.Builder()
                            .corsRules(Arrays.asList(new CfnBucket.CorsRuleProperty.Builder()
                                .allowedOrigins(Arrays.asList("*"))
                                .allowedMethods(Arrays.asList("GET"))
                                .build()))
                            .build())
                        .build();

// L2 Construct
import software.amazon.awscdk.services.s3.*;

public class HelloCdkStack extends Stack {
    public HelloCdkStack(final Construct scope, final String id) {
        this(scope, id, null);
    }

    public HelloCdkStack(final Construct scope, final String id, final StackProps props) {
        super(scope, id, props);

        Bucket.Builder.create(this, "MyFirstBucket")
                .versioned(true).build();
    }
}

2.1.2 Hierarchy - Composition

  • Composition

    • High level construct can be composed from any number of lower level constructs
    • In turn, those could be composed from even lower level constructs
    • Scoping pattern results in a hierarchy of constructs known as a construct tree
  • Composition means you can define reusable components and share them like any other code

2.1.3 Initialization

  • Being implemented in classes that extend the Construct base class

  • 3 parameters

    • scope

      • the construct within which this construct is defined
    • id

      • an identifier that much be unique within this scope
      • serves as a namespace for everything that’s encapsulated within the scope’s subtree
      • used to allocate unique identities such as resource names and AWS CloudFormation logical IDs
    • props

      • a set of properties or keyword arguments
      • define the construct’s initial configuration

3. Java Related

3.1 AWS CDK idioms in Java

  • Props
    • expressed with Builder pattern
    • define a bundle of key/ value pairs that the construct uses to configure the resources it creates
Bucket bucket = new Bucket(this, "MyBucket", new BucketProps.Builder()
                           .versioned(true)
                           .encryption(BucketEncryption.KMS_MANAGED)
                           .build());
  • missing values
    • it will be represented by null

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文章标题:AWS CDK Overview

文章字数:911

本文作者:Leilei Chen

发布时间:2020-08-13, 20:17:35

最后更新:2020-08-13, 20:18:06

原始链接:https://www.llchen60.com/AWS-CDK-Overview/

版权声明: "署名-非商用-相同方式共享 4.0" 转载请保留原文链接及作者。

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