SOA-C02 Question 55
Select 3Your company runs a web application hosted on multiple Amazon EC2 instances behind an Application Load Balancer (ALB). During peak hours, the application experiences high traffic, causing delays and timeouts for users. The application must handle fluctuations in traffic seamlessly without manual intervention. Which combination of actions should you take to implement scalability and elasticity for this application?
- A
Enable Auto Scaling for the EC2 instances by configuring a target tracking scaling policy.
- B
Add more EC2 instances manually during peak hours to handle increased traffic.
- C
Create an Amazon CloudWatch alarm to monitor CPU utilization and trigger scaling actions.
- D
Configure an Auto Scaling group with minimum, maximum, and desired capacity settings.
- E
Migrate the application to a single EC2 instance with a larger instance size to handle peak loads.
Show answer and explanation
Correct answers: A, C, D
Explanation
To implement scalability and elasticity, you should enable Auto Scaling with policies and alarms, allowing the system to dynamically adjust the number of instances based on demand. This ensures seamless handling of fluctuating traffic without manual intervention. Manually adding instances or using a single, larger instance conflicts with the principles of elasticity and scalability.
- A. Correct.
Correct. Enabling Auto Scaling with a target tracking scaling policy ensures that the number of instances dynamically adjusts based on traffic and resource utilization metrics.
- B. Incorrect.
Incorrect. Manually adding instances does not provide the required scalability and elasticity to handle traffic fluctuations automatically.
- C. Correct.
Correct. A CloudWatch alarm can monitor key metrics like CPU utilization, triggering scaling actions automatically based on thresholds.
- D. Correct.
Correct. Configuring an Auto Scaling group with appropriate capacity values ensures that the application can scale out and in effectively based on demand.
- E. Incorrect.
Incorrect. Migrating to a single large instance reduces fault tolerance and elasticity, which are key principles of scalable and elastic architectures.