AWS Certified Solutions Architect – Associate (SAA-C03) — Question 604

A company is building a new furniture inventory application. The company has deployed the application on a fleet ofAmazon EC2 instances across multiple Availability Zones. The EC2 instances run behind an Application Load Balancer (ALB) in their VPC.

A solutions architect has observed that incoming traffic seems to favor one EC2 instance, resulting in latency for some requests.

What should the solutions architect do to resolve this issue?

Answer options

• A. Disable session affinity (sticky sessions) on the ALB
• B. Replace the ALB with a Network Load Balancer
• C. Increase the number of EC2 instances in each Availability Zone
• D. Adjust the frequency of the health checks on the ALB's target group

Correct answer: A

Explanation

Enabling session affinity (sticky sessions) binds a user's session to a specific EC2 target, which can cause uneven traffic distribution if some sessions are more active than others. Disabling this feature allows the ALB to distribute incoming requests evenly across all registered targets using its default routing algorithm. Other options, like changing to a Network Load Balancer or adjusting health check frequency, do not address the root cause of session-based traffic imbalance.