SAP-C02 Question 473
Select 3Your organization has a highly available, critical web application running on AWS. The application is deployed across multiple Availability Zones (AZs) within a single AWS Region using an Auto Scaling group behind an Application Load Balancer (ALB). During a recent outage in one of the AZs, users reported significant latency and intermittent access issues. As a Solutions Architect, how can you improve the reliability of the application while ensuring minimal latency in the event of a similar outage?
- A
Enable cross-zone load balancing on the Application Load Balancer.
- B
Increase the cooldown period for the Auto Scaling group to reduce rapid scaling events.
- C
Configure the Auto Scaling group to launch instances in all available AZs and use weighted target groups for traffic distribution.
- D
Implement an additional Auto Scaling group in another AWS Region and configure Route 53 for active-active failover.
- E
Use Amazon CloudFront with the ALB as the origin to cache content and reduce the load on the backend application.
Show answer and explanation
Correct answers: A, C, D
Explanation
To improve the reliability of the application, you need to ensure traffic is evenly distributed across healthy instances across multiple AZs and regions. Cross-zone load balancing ensures traffic distribution across all instances, even when one AZ is unavailable. Configuring the Auto Scaling group to utilize all AZs and using weighted target groups ensures that healthy instances handle traffic efficiently. Adding an Auto Scaling group in another Region with Route 53 active-active failover extends fault tolerance to the regional level, ensuring continued availability in case of a regional failure.
- A. Correct.
Enabling cross-zone load balancing ensures that the Application Load Balancer can distribute traffic evenly across all available instances, regardless of the AZ they are in, which improves reliability and reduces latency during an AZ outage.
- B. Incorrect.
Increasing the cooldown period for the Auto Scaling group does not directly address reliability or latency issues caused by an AZ outage and may delay the scaling of instances to handle increased traffic.
- C. Correct.
Configuring the Auto Scaling group to launch instances in all available AZs and using weighted target groups ensures that traffic can be better distributed among healthy instances across multiple AZs, improving fault tolerance and reliability.
- D. Correct.
Implementing an additional Auto Scaling group in another AWS Region and configuring Route 53 for active-active failover ensures regional fault tolerance, enabling the application to remain available even during a complete regional failure.
- E. Incorrect.
Using Amazon CloudFront can improve performance and reduce load on the backend, but it does not directly address the reliability issues caused by an AZ outage.