anchor.diff:  
   -   `skip_region_validation` (boolean) - Set to `true` if you want to skip
       validation of the region configuration option. Defaults to `false`.
  -
  --   `snapshot_groups` (array of strings) - A list of groups that have access to
  -    create volumes from the snapshot(s). By default no groups have permission
  -    to create volumes from the snapshot(s). `all` will make the snapshot
  -    publicly accessible.
  -
  --   `snapshot_users` (array of strings) - A list of account IDs that have
  -    access to create volumes from the snapshot(s). By default no additional
  -    users other than the user creating the AMI has permissions to create
  -    volumes from the backing snapshot(s).
   
   -   `source_ami_filter` (object) - Filters used to populate the `source_ami`
       field. Example:
  
positive.code: 
  -   `associate_public_ip_address` (boolean) - If using a non-default VPC,
      public IP addresses are not provided by default. If this is `true`, your
      new instance will get a Public IP. default: `false`
  
  -   `availability_zone` (string) - Destination availability zone to launch
      instance in. Leave this empty to allow Amazon to auto-assign.
  
negative.code: -   `access_key` (string) - The access key used to communicate with AWS. [Learn
      how to set this.](/docs/builders/amazon.html#specifying-amazon-credentials)
  
  -   `instance_type` (string) - The EC2 instance type to use while creating
      the EBS volumes, such as `m1.small`.
  
  -   `region` (string) - The name of the region, such as `us-east-1`, in which
      to launch the EC2 instance to create the new EBS volumes.
  
  -   `secret_key` (string) - The secret key used to communicate with AWS. [Learn
      how to set this.](/docs/builders/amazon.html#specifying-amazon-credentials)
  