AWS Certified Solutions Architect – Associate (SAA-C02) — Question 421

A solutions architect is designing the architecture for a new web application. The application will run on AWS Fargate containers with an Application Load
Balancer (ALB) and an Amazon Aurora PostgreSQL database. The web application will perform primarily read queries against the database.
What should the solutions architect do to ensure that the website can scale with increasing traffic? (Choose two.)

Answer options

• A. Enable auto scaling on the ALB to scale the load balancer horizontally.
• B. Configure Aurora Auto Scaling to adjust the number of Aurora Replicas in the Aurora cluster dynamically.
• C. Enable cross-zone load balancing on the ALB to distribute the load evenly across containers in all Availability Zones.
• D. Configure an Amazon Elastic Container Service (Amazon ECS) cluster in each Availability Zone to distribute the load across multiple Availability Zones.
• E. Configure Amazon Elastic Container Service (Amazon ECS) Service Auto Scaling with a target tracking scaling policy that is based on CPU utilization.

Correct answer: B, E

Explanation

To handle scaling for a read-heavy application, both the compute layer (Fargate) and the database layer (Aurora) must scale. Configuring Amazon ECS Service Auto Scaling based on CPU utilization (Option E) ensures that the Fargate container tasks scale horizontally as traffic increases, while configuring Aurora Auto Scaling (Option B) dynamically adds Aurora Replicas to handle the increased read query load. ALB scaling is managed automatically by AWS without manual auto-scaling configuration (Option A), and ECS clusters are regional resources that span multiple Availability Zones automatically (Option D).