Book Image

Terraform Cookbook

By : Mikael Krief
Book Image

Terraform Cookbook

By: Mikael Krief

Overview of this book

HashiCorp Configuration Language (HCL) has changed how we define and provision a data center infrastructure with the launch of Terraform—one of the most popular and powerful products for building Infrastructure as Code. This practical guide will show you how to leverage HashiCorp's Terraform tool to manage a complex infrastructure with ease. Starting with recipes for setting up the environment, this book will gradually guide you in configuring, provisioning, collaborating, and building a multi-environment architecture. Unlike other books, you’ll also be able to explore recipes with real-world examples to provision your Azure infrastructure with Terraform. Once you’ve covered topics such as Azure Template, Azure CLI, Terraform configuration, and Terragrunt, you’ll delve into manual and automated testing with Terraform configurations. The next set of chapters will show you how to manage a balanced and efficient infrastructure and create reusable infrastructure with Terraform modules. Finally, you’ll explore the latest DevOps trends such as continuous integration and continuous delivery (CI/CD) and zero-downtime deployments. By the end of this book, you’ll have developed the skills you need to get the most value out of Terraform and manage your infrastructure effectively.
Table of Contents (10 chapters)

Zero-downtime deployment with Terraform

As discussed in the previous recipe, changing certain properties on resources described in the Terraform configuration can lead to their destruction and subsequent recreation. Resources are destroyed and recreated in the order in which they are run in Terraform. In other words, the first resource to be run will first be destroyed and then it will be recreated, and in a production context, during this time period, it will lead to downtime, that is, a service interruption. This downtime can be greater or smaller depending on the type of resources that will have to be destroyed and then recreated.

For example, in Azure, a VM takes much longer to destroy and rebuild than a web app or a Network Security Group (NSG) rule.

In Terraform, there is a mechanism that allows for zero downtime and therefore avoids this service interruption when deleting a resource.

In this recipe, we will study how to implement zero downtime on a resource described in a Terraform...