AWS Certified DevOps Engineer – Professional — Question 6

A DevOps Engineer must track the health of a stateless RESTful service sitting behind a Classic Load Balancer. The deployment of new application revisions is through a CI/CD pipeline. If the service's latency increases beyond a defined threshold, deployment should be stopped until the service has recovered.
Which of the following methods allow for the QUICKEST detection time?

Answer options

• A. Use Amazon CloudWatch metrics provided by Elastic Load Balancing to calculate average latency. Alarm and stop deployment when latency increases beyond the defined threshold.
• B. Use AWS Lambda and Elastic Load Balancing access logs to detect average latency. Alarm and stop deployment when latency increases beyond the defined threshold.
• C. Use AWS CodeDeploy's MinimumHealthyHosts setting to define thresholds for rolling back deployments. If these thresholds are breached, roll back the deployment.
• D. Use Metric Filters to parse application logs in Amazon CloudWatch Logs. Create a filter for latency. Alarm and stop deployment when latency increases beyond the defined threshold.

Correct answer: A

Explanation

Option A is the correct answer because using Amazon CloudWatch metrics allows for real-time monitoring and quick detection of latency issues directly tied to the Elastic Load Balancer. Options B and D rely on logs, which typically have higher latency in processing compared to metrics. Option C does not focus on immediate latency detection but rather on rollback criteria, which is not as proactive in addressing latency issues.