Question

A SysOps administrator manages an Application Load Balancer (ALB) that distributes traffic to an Auto Scaling group spanning three Availability Zones. After a recent scaling event, the group has 6 instances in us-east-1a, 2 in us-east-1b, and 2 in us-east-1c. Users report that the instances in us-east-1b and us-east-1c are receiving noticeably higher CPU utilization than those in us-east-1a. What is the most likely cause of this uneven load?

Accepted Answer

Cross-zone load balancing is disabled, so each AZ receives an equal share of traffic regardless of instance count

Answer

The ALB health checks are failing for instances in us-east-1a, removing them from rotation

Answer

Target tracking scaling is misconfigured and only launching instances in us-east-1a

Answer

Connection draining (deregistration delay) is set too high on the target group