AWS Certified DevOps Engineer Professional (DOP-C02) Review Material – CDK

Overview

• AWS Cloud Development Kit (AWS CDK) – an open-source software development framework for defining cloud infrastructure in code and provisioning it through AWS CloudFormation
• Consists of two(2) parts:
  1. CDK Construct Library
     • A collection of pre-written modular and reusable pieces of code, called constructs, that you can use, modify, and integrate to develop your infrastructure quickly. 
  2. CDK CLI
     • A command-line tool for interacting with CDK apps
• Supports the following programming languages:
  • TypeScript,
  • JavaScript
  • Python
  • Java
  • C#/.Net
  • Go
• Difference between Cfn and CDK
  • Cfn defines infrastructure declaratively
  • CDK defines infrastructure imperatively

Core Concepts

• Projects:
  • Represents the files and folders that contain your CDK code.
  • Vary based on your programming language.
  • Universal Files and Folders:
    • .git
    • .gitignore
    • README.md
    • cdk.json – Configuration file for the AWS CDK. This file provides instructions to the AWS CDK CLI regarding how to run your app.
• Apps:
  • A collection of one or more CDK stacks.
  • You create an app by defining an app instance in the application file of your project.
  • Stack ‘constructs’ are defined within the scope of an App construct.
  • Stacks within a single app can easily refer to each other’s resources and properties.
  • The overall grouping of your stacks and constructs is known as your CDK App
• Stacks:
  • The smallest single unit of deployment
  • It represents a collection of AWS resources that you define using CDK constructs.
  • When you deploy CDK apps, the resources within a CDK stack are deployed together as an AWS CloudFormation stack.
  • You define a stack by extending or inheriting from the Stack construct.
  • Stack constructs are defined within the scope of an App construct
  • Stacks are deployed as an AWS CloudFormation stack
  • When you run the 'cdk synth' command for an app with multiple stacks, the cloud assembly includes a separate template for each stack instance.
• Stages:
  • Represents a group of one or more CDK stacks that are configured to deploy together.
  •  Use stages to deploy the same grouping of stacks to multiple environments, such as development, testing, and production.
• Constructs:
  • The basic building blocks of AWS Cloud Development Kit (AWS CDK) applications.
  • A construct is a component within your application that represents one or more AWS CloudFormation resources and their configuration.
  • Constructs are classes that you import into your CDK applications from the AWS Construct Library
  • Construct Levels:
    • Level 1 (L1):
      • Also known as CFN resources.
      • The lowest-level construct offers no abstraction.
      • Each L1 construct maps directly to a single AWS CloudFormation resource. 
    • Level 2 (L2):
      • Also known as curated constructs.
      • Developed by the CDK team and are usually the most widely used construct type.
      • Maps directly to single AWS CloudFormation resources but with higher abstraction.
    • Level 3 (L3):
      • Also known as patterns.
      • The highest level of abstraction.
      • Contains a collection of resources that are configured to work together to accomplish a specific task or service within your application.
      • Used to create entire AWS architectures for particular use cases in your application.
• Context Values:
  • Key-value pairs that can be associated with an app, stack, or construct.
  • Supplied to your app either from a file (usually either cdk.json or cdk.context.json in your project directory) or on the command line.
  • Visible to child constructs, but not to parents or siblings
• Feature Flags:
• Aspects: