title: How to use AWS roles with Packer to create AMIs
body: <p>I'm currently building AMIs via Packer without a problem, but I am baking the AWS credentials into my scripts which is not what I want. Reading the Packer documentation they specify that if no credentials are found it can use an AWS role. </p>
  
  <p>I have created the policy and the role, but it's unclear to me how to tell Packer to use this role. Do I have to pass the ARN in as a variable?</p>
  
  <p>Any thoughts?</p>