KCNA Cloud Native Observability Practice Question
You are an SRE managing a Kubernetes cluster with 200 nodes and 10,000 pods. The cluster runs a critical payment processing application. Users report that transactions are occasionally failing with a 'timeout' error. You have Prometheus and Grafana set up for monitoring, and you use Fluentd with Elasticsearch for logging. You notice that during peak hours, the CPU usage of the payment service pods spikes to 90%, but memory usage remains stable. The pod restart count is low. You also see that the response time of the payment service increases significantly during these spikes. You need to identify the root cause and propose a fix. Which course of action is most appropriate?
⚠ Common exam trap
CNCF often tests the misconception that scaling replicas always solves performance issues, but here the bottleneck is per-pod CPU limits, not overall load distribution.
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
✓
Increase the CPU limits for the payment service pods to allow more CPU resources during spikes
The CPU usage spikes to 90% during peak hours, indicating that the payment service pods are CPU-bound. Increasing CPU limits allows the pods to burst and utilize more CPU resources, reducing response times and preventing timeouts. This directly addresses the bottleneck without adding unnecessary replicas or changing memory settings.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Add more replicas of the payment service to distribute the load
Why it's wrong here
Horizontal scaling helps but may not address the root cause if the service is inefficient; also adds complexity.
- ✗
Increase the memory limits for the payment service pods to improve caching
Why it's wrong here
Memory is stable; increasing memory won't help CPU-bound issues.
- ✗
Implement a circuit breaker pattern to fail fast and avoid timeouts
Why it's wrong here
Circuit breaker prevents cascading failures but doesn't fix the underlying CPU issue.
- ✓
Increase the CPU limits for the payment service pods to allow more CPU resources during spikes
Why this is correct
This directly addresses the CPU bottleneck, reducing response time.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This KCNA practice question is part of Courseiva's free CNCF 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 KCNA exam.