An Auto Scaling group has just scaled up after CloudWatch recorded a spike in the ALB RequestCount metric. The administrator wants to identify the source IP addresses for these requests. Where is this information logged?

Application Load Balancer (ALB) access logs record detailed information about requests sent to your load balancer, including the client's IP address, request type, and response sent. This makes them the definitive source for identifying the source IP addresses of requests that triggered the Auto Scaling event. Auto Scaling service logs track scaling activities, not individual request details. AWS CloudTrail logs API calls made to AWS services, not end-user requests to your application. Logs on the EC2 instances would show requests that reached the instance, but the ALB access logs provide a consolidated view of all traffic hitting the load balancer, including those that might not have been forwarded to an instance due to health checks or other reasons.