SAP-C02 Continuous Improvement for Existing Solutions Practice Question
A company runs a containerized application on Amazon ECS with Fargate. The application uses an Application Load Balancer (ALB) to distribute traffic. The company has configured a target tracking scaling policy based on average memory utilization. During a traffic spike, the ECS service scales out, but the new tasks are immediately deregistered and replaced. The CloudWatch logs show that the new tasks are failing the ALB health check. The health check is configured to ping the '/health' endpoint on the container. The solutions architect verifies that the application container correctly responds to the '/health' endpoint with a 200 status code. What is the MOST likely cause of the health check failures?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The security group attached to the ECS tasks does not allow inbound traffic from the ALB on the health check port.
Since the application container correctly responds to the '/health' endpoint with a 200 status code, the health check failures are likely due to network connectivity. For Fargate tasks, each task gets an ENI, and the security group attached to the tasks must allow inbound traffic from the ALB on the health check port. If this rule is missing, the ALB cannot reach the health check endpoint, causing tasks to be deregistered. Option A is incorrect because the ALB listener rule is for routing traffic, not health checks. Option C is incorrect because a high deregistration delay would cause slow draining, not immediate health check failures. Option D is incorrect because the health check path is confirmed correct by the architect.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The ALB is not configured with a proper listener rule to forward traffic to the target group.
Why it's wrong here
If there were no listener rule, no traffic would reach the tasks, but the task would still be healthy from the ALB's perspective if the health check succeeds.
- ✓
The security group attached to the ECS tasks does not allow inbound traffic from the ALB on the health check port.
Why this is correct
Without inbound rules allowing traffic from the ALB, health checks will fail.
- ✗
The deregistration delay (connection draining) is set too high, causing the ALB to think the tasks are unhealthy.
Why it's wrong here
Deregistration delay affects in-flight requests, not health checks.
- ✗
The health check path is incorrect; it should be '/index.html' instead of '/health'.
Why it's wrong here
The architect confirmed the application correctly responds to '/health'.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SAP-C02 exam.