AWS Certified Solutions Architect – Professional (SAP-C02) — Question 341

A solutions architect is reviewing an application's resilience before launch. The application runs on an Amazon EC2 instance that is deployed in a private subnet of a VPC. The EC2 instance is provisioned by an Auto Scaling group that has a minimum capacity of 1 and a maximum capacity of 1. The application stores data on an Amazon RDS for MySQL DB instance. The VPC has subnets configured in three Availability Zones and is configured with a single NAT gateway.

The solutions architect needs to recommend a solution to ensure that the application will operate across multiple Availability Zones.

Which solution will meet this requirement?

Answer options

• A. Deploy an additional NAT gateway in the other Availability Zones. Update the route tables with appropriate routes. Modify the RDS for MySQL DB instance to a Multi-AZ configuration. Configure the Auto Scaling group to launch the instances across Availability Zones. Set the minimum capacity and maximum capacity of the Auto Scaling group to 3.
• B. Replace the NAT gateway with a virtual private gateway. Replace the RDS for MySQL DB instance with an Amazon Aurora MySQL DB cluster. Configure the Auto Scaling group to launch instances across all subnets in the VPC. Set the minimum capacity and maximum capacity of the Auto Scaling group to 3.
• C. Replace the NAT gateway with a NAT instance. Migrate the RDS for MySQL DB instance to an RDS for PostgreSQL DB instance. Launch a new EC2 instance in the other Availability Zones.
• D. Deploy an additional NAT gateway in the other Availability Zones. Update the route tables with appropriate routes. Modify the RDS for MySQL DB instance to turn on automatic backups and retain the backups for 7 days. Configure the Auto Scaling group to launch instances across all subnets in the VPC. Keep the minimum capacity and the maximum capacity of the Auto Scaling group at 1.

Correct answer: A

Explanation

To achieve true Multi-AZ resilience, high availability must be configured across the network, compute, and database layers. Option A accomplishes this by deploying redundant NAT gateways in each Availability Zone to prevent a single network point of failure, enabling RDS Multi-AZ for synchronous database replication, and scaling the Auto Scaling group to 3 instances to ensure active compute resources exist across all zones. Other options either fail to address database redundancy (Option D), propose incorrect network architectures such as virtual private gateways (Option B), or introduce single points of failure and manual processes (Option C).