AWS Certified Solutions Architect – Associate (SAA-C03) — Question 719

A company wants to migrate its three-tier application from on premises to AWS. The web tier and the application tier are running on third-party virtual machines (VMs). The database tier is running on MySQL.

The company needs to migrate the application by making the fewest possible changes to the architecture. The company also needs a database solution that can restore data to a specific point in time.

Which solution will meet these requirements with the LEAST operational overhead?

Answer options

• A. Migrate the web tier and the application tier to Amazon EC2 instances in private subnets. Migrate the database tier to Amazon RDS for MySQL in private subnets.
• B. Migrate the web tier to Amazon EC2 instances in public subnets. Migrate the application tier to EC2 instances in private subnets. Migrate the database tier to Amazon Aurora MySQL in private subnets.
• C. Migrate the web tier to Amazon EC2 instances in public subnets. Migrate the application tier to EC2 instances in private subnets. Migrate the database tier to Amazon RDS for MySQL in private subnets.
• D. Migrate the web tier and the application tier to Amazon EC2 instances in public subnets. Migrate the database tier to Amazon Aurora MySQL in public subnets.

Correct answer: B

Explanation

Option B is correct because it adheres to the standard secure three-tier architecture by placing the web tier in public subnets and the application and database tiers in private subnets. Amazon Aurora MySQL minimizes operational overhead compared to standard RDS MySQL because it features automatic, continuous, and incremental backups to Amazon S3 with point-in-time recovery (PITR) down to the second. Options A and D are incorrect as they either isolate the web tier from public traffic or unnecessarily expose private application and database components to the public internet.