How to manage multiple regions in AWS provider configuration?

Difficulty: unrated

Source: bregman-arie/devops-exercises by Arie Bregman

Answer

provider "aws" {
  region = "us-west-1"
  alias = "west_region"
}

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

data "aws_region" "west_region" {
  provider = aws.west_region
}

data "aws_region" "east_region" {
  provider = aws.east_region
}

To use it:

resource "aws_instance" "west_region_instance" {
  provider = aws.west_region
  instance_type = "t2.micro"
  ...
}