AWS Certified Solutions Architect – Associate (SAA-C03) — Question 854

A company wants to migrate an application to AWS. The company wants to increase the application's current availability. The company wants to use AWS WAF in the application's architecture.

Which solution will meet these requirements?

Answer options

• A. Create an Auto Scaling group that contains multiple Amazon EC2 instances that host the application across two Availability Zones. Configure an Application Load Balancer (ALB) and set the Auto Scaling group as the target. Connect a WAF to the ALB.
• B. Create a cluster placement group that contains multiple Amazon EC2 instances that hosts the application. Configure an Application Load Balancer and set the EC2 instances as the targets. Connect a WAF to the placement group.
• C. Create two Amazon EC2 instances that host the application across two Availability Zones. Configure the EC2 instances as the targets of an Application Load Balancer (ALB). Connect a WAF to the ALB.
• D. Create an Auto Scaling group that contains multiple Amazon EC2 instances that host the application across two Availability Zones. Configure an Application Load Balancer (ALB) and set the Auto Scaling group as the target. Connect a WAF to the Auto Scaling group.

Correct answer: A

Explanation

AWS WAF can be integrated directly with an Application Load Balancer (ALB), but it cannot be attached to an Auto Scaling group or a placement group, ruling out options B and D. To ensure high availability, deploying an Auto Scaling group across multiple Availability Zones (Option A) is superior to deploying fixed EC2 instances (Option C) because it allows for automatic recovery and scaling. Therefore, using an Auto Scaling group with an ALB and attaching AWS WAF to the ALB is the correct solution.