ANS-C01 Network Management and Operations Practice Question
A company has deployed a web application on EC2 instances behind an Application Load Balancer (ALB). The application is experiencing intermittent timeouts. CloudWatch metrics show that the ALB's RequestCount is within normal limits, but TargetResponseTime occasionally spikes to 10 seconds. What is the most likely cause?
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 EC2 instances are experiencing high CPU utilization during peak periods.
High CPU utilization on the EC2 instances can cause slow response times, leading to timeouts. The ALB distributes requests, so RequestCount may appear normal while individual instances struggle.
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 configured with an incorrect idle timeout value.
Why it's wrong here
Idle timeout affects idle connections, not request processing time.
- ✗
The ALB's cross-zone load balancing is disabled.
Why it's wrong here
Disabling cross-zone can cause uneven load, but RequestCount would show imbalance.
- ✓
The EC2 instances are experiencing high CPU utilization during peak periods.
Why this is correct
High CPU leads to slow responses, matching the symptom of occasional spikes in TargetResponseTime.
- ✗
The security group for the EC2 instances is blocking traffic from the ALB.
Why it's wrong here
A blocking security group would cause outright failures, not intermittent timeouts.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ANS-C01 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 ANS-C01 exam.