We are trying to put up a maintenance webpage for our customers, when our application is down for whatever reason.
Say we have an Application Load Balancer on AWS.
How do we setup an ALB to re-route to a different target group if all checks are failing? Say there are 2 target groups, one is the "primary" target group. And if all instances in that TG are unhealthy, is there a way to then route to a different target group, or a different URL or something?