Terraform for AWS Multi-Region Resource Creation

This article aims to guide you through the process of using Terraform for AWS multi-region resource creation, with a focus on defining AWS regions, creating resources and modules in different regions.

Defining AWS Regions in Terraform

AWS regions serve as geographical areas that consist of two or more Availability Zones. An AWS region is a separate geographic area and having resources in separate AWS regions provides a high degree of fault tolerance.

To work with multiple AWS regions, you would need to define each region separately in your Terraform configuration.

Here is an example of how you can specify AWS regions using the AWS provider in Terraform:

provider "aws" {
  region  = "ap-northeast-1"
}

provider "aws" {
  region  = "us-east-1"
  alias   = "virginia"
}

In the code above, the AWS provider is configured twice, each with a different region - ap-northeast-1 (Asia Pacific (Tokyo)) and us-east-1 (US East (N. Virginia)).

For the second provider, an alias attribute is added to distinguish it from the first.

Creating Resources in Different Regions

Once you have defined the different AWS regions as providers in your Terraform configuration, you can start creating resources in these regions.

To create resources in a different region, you can use the provider attribute to specify which provider (and hence which region) should be used for the resource.

Here is an example of how you can use the provider attribute to create an AWS S3 bucket in the us-east-1 region:

resource "aws_s3_bucket" "bucket_virginia" {
  bucket = "my_bucket"
  acl    = "private"
  provider = aws.virginia
}

In this example, the provider attribute is set to aws.virginia, indicating that the bucket should be created in the us-east-1 region.

Creating Modules in Different Regions

In addition to creating individual resources, you can also use modules to create groups of resources in different regions.

When declaring a module in a different region, you would use the providers attribute to specify which providers should be used for the resources within the module.

Here is an example of how you can use the providers attribute in a module declaration:

module "my_module_virginia" {
  source = "./path/to/module"
  variable_value = "my_value"
  providers = {
    aws = aws.virginia
  }
}

In this example, the providers attribute is set to aws.virginia, meaning that all resources within the module will be created in the us-east-1 region.

References

https://developer.hashicorp.com/terraform/language/providers/configuration