Book Image

Mastering AWS CloudFormation

By : Karen Tovmasyan
Book Image

Mastering AWS CloudFormation

By: Karen Tovmasyan

Overview of this book

DevOps and the cloud revolution have forced software engineers and operations teams to rethink how to manage infrastructures. With this AWS book, you'll understand how you can use Infrastructure as Code (IaC) to simplify IT operations and manage the modern cloud infrastructure effectively with AWS CloudFormation. This comprehensive guide will help you explore AWS CloudFormation from template structures through to developing complex and reusable infrastructure stacks. You'll then delve into validating templates, deploying stacks, and handling deployment failures. The book will also show you how to leverage AWS CodeBuild and CodePipeline to automate resource delivery and apply continuous integration and continuous delivery (CI/CD) practices to the stack. As you advance, you'll learn how to generate templates on the fly using macros and create resources outside AWS with custom resources. Finally, you'll improve the way you manage the modern cloud in AWS by extending CloudFormation using AWS serverless application model (SAM) and AWS cloud development kit (CDK). By the end of this book, you'll have mastered all the major AWS CloudFormation concepts and be able to simplify infrastructure management.
Table of Contents (17 chapters)
1
Section 1: CloudFormation Internals
4
Section 2: Provisioning and Deployment at Scale
9
Section 3: Extending CloudFormation

Using cfn-signal to inform CloudFormation about resource readiness

CloudFormation reports resource readiness as soon as it retrieves a response from AWS's API that the resource is created. By this, we understand that if we create an RDS instance and CloudFormation tells us that it's created, then we can connect to it right away.

While this is applicable for most of the managed services at AWS, it doesn't work on services that we run based on EC2. You see, CloudFormation is not aware that EC2 has a job to run and reports Done once the instance is in a Running state.

For small development environments this might be fine, but imagine running a web application on an AutoScaling group. While the instance takes time to install packages and start services, AutoScaling reports that the instance is unhealthy and terminates it. A new one starts, time passes, and then gets terminated. The worst thing here is that CloudFormation will tell you that your AutoScaling group is...