A new web application is launched on multiple EC2 instances behind an Application Load Balancer in an Auto Scaling group. Users complain they are being asked to log in repeatedly. What should the SysOps administrator do to stop frequent reauthentication?

Enabling session affinity (sticky sessions) on the ALB target group ensures that requests from a specific user are consistently routed to the same EC2 instance. This is crucial for applications that store session data locally on the instance, preventing users from being reauthenticated when their subsequent requests are routed to a different instance. Putting a CloudFront distribution in front of the ALB primarily caches content and improves performance, but it doesn't directly address session management across backend instances. Rebuilding EC2 instances in a spread placement group improves fault tolerance by distributing instances across underlying hardware, but it doesn't solve the session reauthentication issue. Replacing the Application Load Balancer with a Network Load Balancer would operate at Layer 4, losing the advanced routing capabilities, including sticky sessions, that an ALB provides.