infra-live

Using IAC with Terragrunt :)

How is the code in this repo organized?

The code in this repo uses the following folder hierarchy:

account
 └ _global
 └ region
    └ _global
    └ environment
       └ resource

Where:

• Account: At the top level are each of your AWS accounts, such as stage-account, prod-account, mgmt-account, etc. If you have everything deployed in a single AWS account, there will just be a single folder at the root (e.g. main-account).

• Region: Within each account, there will be one or more AWS regions, such as us-east-1, eu-west-1, and ap-southeast-2, where you've deployed resources. There may also be a _global folder that defines resources that are available across all the AWS regions in this account, such as IAM users, Route 53 hosted zones, and CloudTrail.

• Environment: Within each region, there will be one or more "environments", such as qa, stage, etc. Typically, an environment will correspond to a single AWS Virtual Private Cloud (VPC), which isolates that environment from everything else in that AWS account. There may also be a _global folder that defines resources that are available across all the environments in this AWS region, such as Route 53 A records, SNS topics, and ECR repos.

• Resource: Within each environment, you deploy all the resources for that environment, such as EC2 Instances, Auto Scaling Groups, ECS Clusters, Databases, Load Balancers, and so on. Note that the Terraform code for most of these resources lives in the terragrunt-infrastructure-modules-example repo.

Creating and using root (account) level variables

In the situation where you have multiple AWS accounts or regions, you often have to pass common variables down to each of your modules. Rather than copy/pasting the same variables into each terragrunt.hcl file, in every region, and in every environment, you can inherit them from the inputs defined in the root terragrunt.hcl file.