AWS Certified DevOps Engineer – Professional — Question 92
A DevOps engineer is troubleshooting deployments to a new application that runs on Amazon EC2 instances behind an Application Load Balancer. The instances run in an EC2 Auto Scaling group across multiple Availability Zones. Instances sometimes come online before they are ready, which is leading to increased error rates among users. The current health check configuration gives instances a 60-second grace period and considers instances healthy after two 200 response codes from /index.php, a page that may respond intermittently during the deployment process. The development team wants instances to come online as soon as possible.
Which strategy would address this issue?
Answer options
- A. Increase the instance grace period from 60 seconds to 180 seconds, and the consecutive health check requirement from 2 to 3.
- B. Increase the instance grace period from 60 seconds to 120 seconds, and change the response code requirement from 200 to 204.
- C. Modify the deployment script to create a /health-check.php file when the deployment begins, then modify the health check path to point to that file.
- D. Modify the deployment script to create a /health-check.php file when all tasks are complete, then modify the health check path to point to that file.
Correct answer: D
Explanation
The correct answer is D because it ensures that the health check only verifies the instance's readiness after the deployment is fully complete, avoiding premature availability. Options A and B do not resolve the issue of instances becoming available too early by merely extending the grace period or changing response codes. Option C risks checking the health of instances before deployment completion, leading to potential errors.