AWS Config pode ser o serviço correto para você. Aqui está a sinopse da AWS
AWS Config is a service that enables you to assess, audit, and evaluate the configurations of your AWS resources. Config continuously monitors and records your AWS resource configurations and allows you to automate the evaluation of recorded configurations against desired configurations. With Config, you can review changes in configurations and relationships between AWS resources, dive into detailed resource configuration histories, and determine your overall compliance against the configurations specified in your internal guidelines. This enables you to simplify compliance auditing, security analysis, change management, and operational troubleshooting.
Você também pode usar metadados de instância . Ele retorna uma variedade de dados, mas o principal que você quer é "região".
curl http://169.254.169.254/latest/dynamic/instance-identity/document
{
"region" : "us-west-2"
}