SAA-C03 Question 367
Single answerA company is hosting a web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The application receives unpredictable traffic that can spike suddenly. The company wants to ensure the application performs well during traffic spikes while minimizing costs during low traffic periods. Which configuration meets these requirements?
- A
Use a fixed size Auto Scaling group with a set number of EC2 instances.
- B
Configure an Auto Scaling group with step scaling policies based on CPU utilization thresholds.
- C
Deploy the application on On-Demand Instances only and manually scale the EC2 instances during traffic spikes.
- D
Use Spot Instances to run the application and scale manually during peak traffic.
Show answer and explanation
Correct answer: B
Explanation
Step scaling policies in an Auto Scaling group dynamically adjust the number of EC2 instances based on predefined CPU utilization thresholds. This ensures sufficient capacity during traffic spikes while reducing costs during low traffic by scaling down. This approach aligns with the requirement for performance and cost optimization.
- A. Incorrect.
A fixed size Auto Scaling group does not adapt to changes in traffic, leading to under-provisioning during traffic spikes or over-provisioning during low traffic periods.
- B. Correct.
Step scaling policies in an Auto Scaling group allow EC2 instances to scale in or out dynamically based on CPU utilization thresholds, meeting performance requirements during traffic spikes while minimizing costs during low traffic.
- C. Incorrect.
Manually scaling EC2 instances is inefficient and error-prone, especially with unpredictable traffic. This approach does not meet the requirement for automated scaling.
- D. Incorrect.
Spot Instances are cost-effective but are not suitable for unpredictable traffic spikes because they can be interrupted with very little notice. Manual scaling also adds operational overhead and does not fulfill the requirement for dynamic scaling.