- `access_key` (string) - The access key used to communicate with AWS. [Learn how to set this] (/docs/builders/amazon.html#specifying-amazon-credentials). On EBS, this is not required if you are using `use_vault_aws_engine` for authentication instead. - `region` (string) - The name of the region, such as `us-east-1`, in which to launch the EC2 instance to create the AMI. When chroot building, this value is guessed from environment. - `secret_key` (string) - The secret key used to communicate with AWS. [Learn how to set this](amazon.html#specifying-amazon-credentials). This is not required if you are using `use_vault_aws_engine` for authentication instead.