I currently have an elastic load balancer with some servers behind it. I want them to scale as traffic moves up and down.
I currently have a scaling policy to add instances whenever CPU util is over 50% for 60 seconds. This sort of works OK.
However, how can I trigger an auto scaling action when there are no healthy instances? So if there's a rush of traffic and the servers just die, they don't report CPU util over 50% and nothing happens to the auto scaling.
How can I set up ELB/auto scaling to jump in as soon as there are no healthy instances? Or is there a better way to achieve this?