You run your application on 5 EC2 instances on one AZ and on 10 EC2 instances in another AZ. You distribute traffic between all of them using a network load balancer, but it seems that instances in one AZ have higher CPU rates than the instances in the other AZ. What might be the issue and how to solve it?
Answer
It's possible that traffic is distributed evenly between the AZs but that doesn't mean it's distributed equally across all instances evenly.
To distribute it evenly between all the instances, you have to enable cross-zone load balancing.