AWS Certified Solutions Architect – Associate (SAA-C02) — Question 24

A company has a multi-tier application that runs six front-end web servers in an Amazon EC2 Auto Scaling group in a single Availability Zone behind an
Application Load Balancer (ALB). A solutions architect needs to modify the infrastructure to be highly available without modifying the application.
Which architecture should the solutions architect choose that provides high availability?

Answer options

• A. Create an Auto Scaling group that uses three instances across each of two Regions.
• B. Modify the Auto Scaling group to use three instances across each of two Availability Zones.
• C. Create an Auto Scaling template that can be used to quickly create more instances in another Region.
• D. Change the ALB in front of the Amazon EC2 instances in a round-robin configuration to balance traffic to the web tier.

Correct answer: B

Explanation

The correct answer is B because utilizing multiple Availability Zones within a single region provides redundancy and fault tolerance, ensuring that if one zone fails, the application can still function using instances in another zone. Options A and C involve multiple regions, which adds complexity and doesn't address high availability within the same region. Option D does not improve availability; it merely changes the traffic distribution method without adding redundancy.