During load testing, high CPU on EC2 instances behind an ALB causes the Auto Scaling group to scale out. You need to diagnose the high CPU issue on the instances before new instances are launched. What action will prevent additional scale-out events so you can troubleshoot?

Suspending the Launch and Terminate processes for the Auto Scaling group will prevent new instances from being launched and existing instances from being terminated, effectively pausing scaling activities. This allows you to troubleshoot the high CPU issue on the current instances without the Auto Scaling group interfering by adding or removing instances. Enabling instance scale-in protection would only prevent termination, not new launches. Putting an instance into Standby removes it from active service but doesn't stop the Auto Scaling group from launching new instances if the scaling policy is still met. Removing the listener from the ALB would stop traffic to all instances, which is too drastic and doesn't directly address preventing scale-out while troubleshooting.