Question #1658
A gaming platform is experiencing performance issues due to uneven traffic distribution across its backend servers. The platform uses an Application Load Balancer (ALB) to route traffic to Amazon EC2 instances deployed in multiple Availability Zones within a VPC. Monitoring shows that one EC2 instance is handling a disproportionate share of requests, leading to increased latency. What should the solutions architect recommend to address this issue?
Disable session affinity (sticky sessions) on the ALB
Replace the ALB with a Gateway Load Balancer
Increase the number of EC2 instances in each Availability Zone
Modify the health check thresholds on the ALB's target group
Explanation
The correct answer is A because session affinity (sticky sessions) routes requests from the same client to the same EC2 instance, which can lead to uneven traffic distribution if some clients generate more requests. Disabling this feature allows the ALB to use its default round-robin or least-connections algorithm, balancing traffic more effectively.
Why other options are incorrect:
- B: Gateway Load Balancers (GWLB) are designed for deploying third-party network appliances, not general traffic distribution.
- C: Adding more instances may not resolve the issue if the ALB's routing logic (e.g., sticky sessions) is causing imbalance.
- D: Health check thresholds determine instance availability but do not affect traffic distribution logic.
Key Points:
- Sticky sessions can cause uneven load if client request patterns vary.
- ALB's default routing algorithms (round-robin/least-connections) ensure balanced traffic when sticky sessions are disabled.
Answer
The correct answer is: A