Q67 — AWS DOP-C02 Ch.1
Question 67 of 100 | ← Chapter 1
A DevOps engineer is troubleshooting deployment of a new application running on Amazon EC2 instances behind an Application Load Balancer. The instances run in an EC2 Auto Scaling group spanning multiple Availability Zones. Instances register with the load balancer before becoming fully ready, causing increased customer error rates. Current health check configuration grants a 60-second grace period and marks an instance healthy after a single 200 response from /index.php — a page that may intermittently respond during deployment. The development team wants instances to become available as quickly as possible. Which strategy resolves this issue?
- A. Increase the instance grace period from 60 seconds to 180 seconds and increase the consecutive health check requirement from 2 to 3.
- B. Increase the instance grace period from 60 seconds to 120 seconds and change the expected HTTP response code from 200 to 204.
- C. Modify the deployment script to create a /health-check.php file at the start of deployment, then update the health check path to point to that file.
- D. Modify the deployment script to create a /health-check.php file only after all deployment tasks complete, then update the health check path to point to that file. ✓
Correct Answer: D. Modify the deployment script to create a /health-check.php file only after all deployment tasks complete, then update the health check path to point to that file.
Explanation
The core issue is premature registration of instances before full readiness, increasing error rates. To balance rapid availability with reliability, health checks must reflect actual readiness. Option A extends delays without guaranteeing readiness. Option B changes timing and status codes but still risks false positives. Option C creates the health check file too early, allowing registration before completion. Option D ensures the health check endpoint only becomes available after all deployment tasks finish — guaranteeing readiness before registration. This satisfies both correctness and speed requirements. Thus, Option D is correct.