AWS Certified SysOps Administrator – Associate — Question 278

A company hosts an internet web application on Amazon EC2 instances. The company is replacing the application with a new AWS Lambda function. During a transition period, the company must route some traffic to the legacy application and some traffic to the new Lambda function. The company needs to use the URL path of request to determine the routing.

Which solution will meet these requirements?

Answer options

• A. Configure a Gateway Load Balancer to use the URL path to direct traffic to the legacy application and the new Lambda function.
• B. Configure a Network Load Balancer to use the URL path to direct traffic to the legacy application and the new Lambda function.
• C. Configure a Network Load Balancer to use a regular expression to match the URL path to direct traffic to the new Lambda function.
• D. Configure an Application Load Balancer to use the URL path to direct traffic to the legacy application and the new Lambda function.

Correct answer: D

Explanation

An Application Load Balancer (ALB) operates at Layer 7 and natively supports path-based routing rules, allowing it to direct traffic to different target groups, including EC2 instances and AWS Lambda functions. Network Load Balancers and Gateway Load Balancers operate at lower layers of the OSI model (Layer 4 and Layer 3, respectively) and cannot inspect HTTP URL paths to make routing decisions. Thus, only an ALB can satisfy the requirement of routing traffic to EC2 and Lambda based on the URL path.