SAP-C02 Question 156
Select 2A company is running a highly available web application using an Auto Scaling group of Amazon EC2 instances behind an Application Load Balancer (ALB) in multiple Availability Zones. The company wants to reduce costs while ensuring consistent performance during peak hours. They also want to optimize costs during off-peak hours by scaling down to the minimum number of instances. What combination of actions should you recommend to achieve these requirements?
- A
Configure Auto Scaling policies with scheduled scaling to increase capacity during peak hours and decrease capacity during off-peak hours.
- B
Enable EC2 Spot Instances in the Auto Scaling group to handle peak traffic and reduce costs.
- C
Use AWS Lambda to replace the Auto Scaling group and dynamically manage traffic based on incoming requests.
- D
Set up an Auto Scaling group with target tracking scaling policies based on CPU utilization metrics.
- E
Move the application to a single Availability Zone to save costs on cross-AZ data transfer.
Show answer and explanation
Correct answers: A, D
Explanation
The company requires a cost-effective and scalable solution to handle both peak and off-peak traffic while maintaining high availability. Scheduled scaling (option 1) ensures predictable capacity adjustments, while target tracking scaling policies (option 4) dynamically optimize resources based on utilization. Spot Instances (option 2) are not reliable for applications requiring consistent performance, and AWS Lambda (option 3) is unsuitable for the described web application architecture. Moving to a single Availability Zone (option 5) sacrifices high availability, which is not acceptable in this scenario.
- A. Correct.
This is correct because scheduled scaling allows you to predefine scaling actions based on predictable traffic patterns, ensuring sufficient capacity during peak hours and cost savings during off-peak hours.
- B. Incorrect.
This option is incorrect because Spot Instances, while cost-effective, are not suitable for applications requiring consistent performance due to their potential for sudden interruptions.
- C. Incorrect.
This option is incorrect because AWS Lambda is not designed to replace EC2 instances for stateful or long-running web applications. It is better suited for event-driven tasks.
- D. Correct.
This is correct because target tracking scaling policies dynamically adjust the number of EC2 instances based on actual utilization, ensuring cost optimization and performance efficiency.
- E. Incorrect.
This option is incorrect because moving to a single Availability Zone compromises high availability and fault tolerance, which is critical for the given scenario.