How do you put up a maintenance page in AWS when you want to deploy new versions of your application behind an ELB? We want to have the ELB route traffic to the maintenance inst
The simplest way on AWS is to use Route 53, their DNS service.
You can use the feature of Weighted Round Robin.
"You can use WRR to bring servers into production, perform A/B testing, or balance your traffic across regions or data centers of varying sizes."
More information in AWS documentations on this feature
EDIT: Route 53 recently added a new feature that allows DNS Failover to S3. Check their documentation for more details: http://docs.aws.amazon.com/Route53/latest/DeveloperGuide/dns-failover.html