Book Image

Mastering AWS CloudFormation - Second Edition

By : Karen Tovmasyan
Book Image

Mastering AWS CloudFormation - Second Edition

By: Karen Tovmasyan

Overview of this book

The advent of DevOps and the cloud revolution has compelled software engineers and operations teams to rethink how to manage complex infrastructures and build resilient solutions. With this AWS book, you’ll find out how you can use Infrastructure as Code (IaC) to simplify infrastructure operations and manage the modern cloud with AWS CloudFormation. This guide covers AWS CloudFormation comprehensively, from template structures to developing complex and reusable infrastructure stacks. It takes you through template validation, stack deployment, and handling deployment failures. It also demonstrates the use of AWS CodeBuild and CodePipeline for automating resource delivery and implementing continuous integration and continuous delivery (CI/CD) practices. As you advance, you’ll learn how to modularize and unify your template on the fly using macros or by fixating the version using modules. You’ll create resources outside of AWS with custom resources and catalog them with the CloudFormation registry. Finally, you’ll improve the way you manage the modern cloud environment on AWS by extending CloudFormation through the AWS serverless application model (SAM) and the AWS cloud development kit (CDK). By the end of this book, you’ll have mastered key AWS CloudFormation concepts and will be able to extend its capabilities for developing and deploying your own infrastructure.
Table of Contents (19 chapters)
Free Chapter
1
Part 1: CloudFormation Internals
4
Part 2: Provisioning and Deployment at Scale
9
Part 3: Extending CloudFormation

The internals of the underlying Lambda function

A Lambda function is code that is triggered by an event. Once run, it receives event and context objects and runs internal code that will process these objects.

While the context object is just metadata of the Lambda function’s execution and can be used for self-maintenance and graceful shutdown, the event object contains the payload that we want to focus on.

In the case of CRs, we will need to parse the stack’s information, run our logic, and respond to CloudFormation. The response should contain the following fields:

  • Status (either SUCCESS/FAILED).
  • Physical resource ID (since it is custom, we need to come up with our own resource ID).
  • Stack ID (the same as from the CR request).
  • Request ID (the same as from the CR request).
  • Logical resource ID (the same as from the CR request).
  • Data (may or may not be unnecessary, used for the intrinsic Fn::GetAtt function).
  • After processing and running...