Comment 1 for bug 1388140

Relatedly, AutoScalingGroup doesn't validate before creation:

heat_template_version: 2013-05-23

resources:
  config:
    type: OS::Heat::AutoScalingGroup
    properties:
      resource:
        type: My::ConfiguredServer
      desired_capacity: 2
      max_size: 4
      min_size: 1

This ends up CREATE_FAILED if you forget to pass the environment mapping the My::ConfiguredServer type.