AWS Certified SysOps Administrator – Associate (legacy) — Question 575

A company uses multiple accounts for its applications. Account A manages the company's Amazon Route 53 domains and hosted zones. Account B uses a load balancer fronting the company's web servers.
How can the company use Route 53 to point to the load balancer in the MOST cost-effective and efficient manner?

Answer options

• A. Create an Amazon EC2 proxy in Account A that forwards requests to Account B.
• B. Create a load balancer in Account A that points to the load balancer in Account B.
• C. Create a CNAME record in Account A pointing to an alias record for the load balancer in Account B.
• D. Create an alias record in Account A pointing to the DNS name for the load balancer in Account B.

Correct answer: D

Explanation

Creating an alias record in Account A that points to the DNS name of the load balancer in Account B is the most cost-effective and efficient solution because Route 53 does not charge for alias queries to AWS resources, and it resolves without extra network hops. Options A and B introduce unnecessary infrastructure costs, complexity, and latency by deploying proxy servers or additional load balancers. Option C is less efficient and more expensive because CNAME queries are billed by Route 53 and require an additional DNS lookup step.