Achieving High Availability and Efficient Load Distribution Using AWS Cross-Zone Load Balancing

AMJ Cloud Technologies collaborated with a fast-growing e-commerce company to optimize their AWS-based web application using Cross-Zone Load Balancing. This case study showcases how we achieved balanced traffic distribution, improved performance, and ensured high availability.

Situation

The client, an e-commerce company serving thousands of users across multiple regions, hosted their web application on AWS with an Application Load Balancer (ALB) and EC2 instances across two Availability Zones (AZ-A and AZ-B). Despite the multi-AZ setup, they faced inconsistent server performance and slowdowns during peak traffic. With cross-zone load balancing disabled, AZ-A (with two instances) handled 50% of traffic, causing CPU spikes, while AZ-B (with four instances) was underutilized, leading to latency and timeouts.

Task

Our team was tasked with designing a solution to meet the following objectives:

• Distribute traffic evenly across all EC2 instances, regardless of AZ.
• Reduce latency and eliminate performance degradation during peak traffic.
• Ensure high availability during AZ-specific incidents.
• Optimize resource utilization to improve cost-efficiency.
• Implement changes with minimal disruption to operations.

The project was executed by a team of cloud architects and DevOps engineers over a one-month timeline.

Action

To achieve these objectives, we enabled Cross-Zone Load Balancing on the client’s Application Load Balancer and validated the setup for performance and resilience:

1. Load Balancer Reconfiguration:

   • Enabled Cross-Zone Load Balancing on the AWS Application Load Balancer using the AWS Console and AWS CLI.
   • Ensured traffic was distributed evenly across all registered EC2 instances, regardless of their AZ location.

2. Instance Scaling Validation:

   • Verified that all EC2 instances in target groups were healthy and properly registered with the ALB.
   • Validated EC2 Auto Scaling configurations to ensure instances scaled appropriately during traffic surges.

3. Testing Load Distribution:

   • Conducted simulated traffic tests to confirm even distribution across the six EC2 instances (two in AZ-A, four in AZ-B).
   • Monitored CPU utilization and response times to ensure balanced performance.

4. Failover Testing:

   • Simulated an AZ-A failure to test the ALB’s ability to route traffic to healthy instances in AZ-B.
   • Confirmed seamless failover without manual intervention, ensuring high availability.

The team collaborated with the client to monitor metrics during rollout and fine-tuned configurations to optimize performance.

Result

The Cross-Zone Load Balancing implementation delivered significant outcomes:

• Even Traffic Distribution Across All EC2 Instances: Each instance received ~16.7% of traffic, eliminating AZ-A overload.
• 25% Reduction in Latency During Peak Periods: Improved response times and lower CPU utilization enhanced user experience.
• Seamless Failover During AZ Failures: Maintained application uptime during simulated outages.
• Optimized Infrastructure Costs with No Idle Servers: Improved resource utilization for predictable scaling.
• Operational Simplicity: Quick implementation with minimal disruption.

This solution has become a reference for AMJ Cloud Technologies’ load balancing projects, showcasing our expertise in AWS high-availability architectures.

Technologies Used

• AWS Application Load Balancer (ALB): Managed incoming traffic.
• Cross-Zone Load Balancing: Enabled even traffic distribution.
• EC2 Auto Scaling: Scaled instances dynamically.
• Multi-AZ Architecture: Enhanced fault tolerance.
• AWS CLI: Configured load balancer settings.

Key Use Cases

This architecture is suitable for:

• E-commerce platforms with multi-AZ deployments.
• Web applications requiring consistent performance during traffic spikes.
• Enterprises seeking cost-efficient, high-availability solutions.

Ready to optimize your load balancing? Contact us to explore how AMJ Cloud Technologies can help.

Key Takeaways

This case study highlights the impact of AWS Cross-Zone Load Balancing in achieving efficient traffic distribution and high availability. By enabling a simple yet powerful feature, we enhanced performance, optimized resources, and ensured resilience for an e-commerce client. AMJ Cloud Technologies is dedicated to delivering practical cloud solutions for scalable architectures.

Architectural Diagram