An Auto Scaling group has two nearly identical scaling policies: one adds 5 instances when average CPU reaches 80%, and the other adds 10 instances at the same 80% threshold. When the CPU hits 80%, what will the Auto Scaling group do?

When multiple scaling policies are triggered simultaneously by the same alarm, Amazon EC2 Auto Scaling applies the policy that results in the largest capacity change. In this scenario, both policies are triggered when the average CPU reaches 80%. One policy adds 5 instances, and the other adds 10 instances. Since adding 10 instances represents a larger capacity change than adding 5 instances, Auto Scaling will execute the policy that adds 10 instances. It does not add both (15 instances) and does not fail due to conflict; it intelligently chooses the most impactful scaling action.