A Professional Educational Institution maintains a dedicated web server and database cluster that hosts an exam results portal undertaken by its students. The resource is idle for most of the learning cycle and becomes excessively busy when exam results are released. How can this architecture with servers be improved to be cost-efficient?

Answer options:

A.Configure AWS Elastic load-balancing between the webserver and database cluster.
B.Configure RDS multi-availability zone for performance optimization.
C.Configure serverless architecture leveraging AWS Lambda functions.
D.Migrate the web servers onto Amazon EC2 Spot Instances.

Correct Answer – C
Leveraging AWS Lambda functions will remove the need to run a dedicated web server for the organization. During periods of high requests to the database cluster, AWS lambda back-end infrastructure will automatically scale out resources to meet the demand adequately. AWS Lambda provides a platform to run code without provisioning or managing any servers. The organization pays only for the compute time they consume. There is no charge when your code is not running. Lambda functions can reduce the cost significantly.
https://aws.amazon.com/lambda/
Option A INCORRECT because the premise of the scenario is about cost-efficiency more than load and server responsiveness. The addition of Elastic load balancing will increase the cost based on the number of instances. So this option is not cheaper.
https://aws.amazon.com/elasticloadbalancing/
Option B is INCORRECT because RDS Multi-AZ helps with disaster recovery, enhanced availability, and durability. However, the scenario requires a solution that reduces the cost of maintaining the organization`s infrastructure.
https://aws.amazon.com/rds/details/multi-az/
Option D is INCORRECT because migrating to Amazon EC2 Spot Instances may negatively impact the service during periods of high traffic. Instances could be terminated mid-transaction that would have adverse effects on the overall user experience. This would not be a cost-effective solution. Spot Instances let you to take advantage of unused EC2 capacity in the AWS cloud. Spot Instances are available at up to a 90% discount compared to On-Demand prices. Spot Instances can reclaim the capacity back with two minutes of notice.
https://aws.amazon.com/ec2/spot/
Note: You can test the pricing of different AWS services by using Pricing Calculator.
https://calculator.aws/#/