Question Set 1 – Explanation of wrong answer seems incorrect

[Luke Wacholtz]

Here is the question with the correct answer and the wrong answer with the confusing explanation.

Category: CSAP – Design for New Solutions

A company is hosting its flagship product page on a three-tier web application in its on-premises data center. The popularity of the last product launch attracted a sudden surge of traffic to their site, which caused some downtime that resulted in a significant impact on the product’s sales volume. The management decided to move the application to AWS. The application uses a MySQL database and is written in .NET framework. The Solutions Architect must design a highly available and scalable infrastructure to handle the demand of 300,000 peak users.

Which of the following design options would satisfy the above requirements while being cost-effective?

Correct Answer

Launch a CloudFormation stack that contains an Auto Scaling Group of Amazon EC2 instances spanning multiple Availability Zones that are behind an Application Load Balancer. Use the stack to launch an Amazon Aurora MySQL database cluster in a Multi-AZ configuration with a “retain” deletion policy. Create a Route 53 zone entry for the company’s domain name with an Alias-record pointed to the ALB.

Wrong Answer

Create an AWS Elastic Beanstalk application that contains a web server tier and an Amazon RDS MySQL Multi-AZ database tier. The web server tier should launch a fleet of Amazon EC2 Auto Scaling Group spanning multiple Availability Zones and behind a Network Load Balancer. Create a Route 53 zone entry for the company’s domain name with an Alias-record pointed to the NLB is incorrect. You do not need an expensive Network Load Balancer (NLB) to handle the expected peak traffic. An NLB is a good choice if you expect millions of requests per second.

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The explanation of the wrong answer is confusing to me because it appears that NLBs are generally cheaper than ALBs (and an ALB is used in the correct answer).

https://aws.amazon.com/elasticloadbalancing/pricing/?nc=sn&loc=3

I’m not disputing the correctness of the correct answer, only that the explanation of the wrong answer is confusing.

Am I mistaken about the pricing on the NLBs somehow or should the explanation of the wrong answer be updated?

[Kenneth-Samonte-Tutorials-Dojo]

Hi Luke,

Thank you for the feedback.

I would generally choose an Application Load Balancer (ALB) for general load balancing questions. I would only choose a Network Load Balancer for specific scenarios that have specific requirements such as:

– need to be able to handle millions of requests per second, with very minimal latency

– Application requires TCP/UDP connections (ALB is limited to only HTTP/HTTPS connections)

– Requires ultra low latency connections.

– preserves the client-side source IP allowing the back-end to see the IP address of the client

– Load Balancer requires a static or elastic IP.

As for the pricing for ALB vs. NLB, AWS pricing changes may have lowered the pricing for using an NLB. AWS usually changes the prices popular services, depending on region, without any further notice. Our team will review the explanation and will update it accordingly.

Thank you.

Let us know if you need further assistance. The Tutorials Dojo team is dedicated to helping you pass your AWS exam!

Regards,

Kenneth Samonte @ Tutorials Dojo