title: Add custom header to Amazon AWS ELB response
body: <p>I would like to add a custom header to the responses generated by an Elastic Load Balancer. This custom header should contain the EC2 instance ID (something like X-EC2-Instance-ID=123456) corresponding to the backend who has handled the request.</p>
  
  <p>Is it possible to do this from the ELB itself, without configuring this header on each backend server?</p>
  
  <p>thanks!</p>