Book Image

Getting Started with Terraform - Second Edition

By : Kirill Shirinkin
1 (1)
Book Image

Getting Started with Terraform - Second Edition

1 (1)
By: Kirill Shirinkin

Overview of this book

Terraform is a tool used to efficiently build, configure, and improve the production infrastructure. It can manage the existing infrastructure as well as create custom in-house solutions. This book shows you when and how to implement infrastructure as a code practices with Terraform. It covers everything necessary to set up the complete management of infrastructure with Terraform, starting with the basics of using providers and resources. It is a comprehensive guide that begins with very small infrastructure templates and takes you all the way to managing complex systems, all using concrete examples that evolve over the course of the book. The book ends with the complete workflow of managing a production infrastructure as code—this is achieved with the help of version control and continuous integration. The readers will also learn how to combine multiple providers in a single template and manage different code bases with many complex modules. It focuses on how to set up continuous integration for the infrastructure code. The readers will be able to use Terraform to build, change, and combine infrastructure safely and efficiently.
Table of Contents (15 chapters)
Title Page
About the Author
About the Reviewer
Customer Feedback

Handling resource updates

Let's change our instance's name to be hello-updated-instance:

resource "aws_instance" "hello-instance" {  ami = "ami-9bf712f4"  instance_type = "t2.micro"  subnet_id = "subnet-5f22f536"  tags {    Name = "hello-update-instance"  }}

Before we actually run the update, wouldn't it be useful to see what exactly Terraform do when we run the terraform apply command again? Luckily, there is the terraform plan command that does exactly the same, that is, it shows you what applying do by checking the template, state file, and actual state of the resource:

$> terraform planRefreshing Terraform state in-memory prior to plan...The refreshed state will be used to calculate this plan, butwill not be persisted to local or remote state storage.aws_instance.hello-instance: Refreshing state... (ID: i-119a10ac)The Terraform execution plan has been generated and is shown below.Resources are shown in alphabetical order for quick scanning. Green resourceswill be created (or destroyed...