KCNA Cloud Native Observability Practice Question
Which component is responsible for aggregating metrics from Kubernetes nodes and exposing them to the metrics API?
⚠ Common exam trap
A common mix-up: candidates confuse Prometheus (a full monitoring system) with the metrics-server (a lightweight, Kubernetes-native component for the Metrics API), assuming Prometheus is required for `kubectl top` or HPA when in fact the metrics-server is the dedicated and simpler solution.
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
✓
metrics-server
The metrics-server is the correct component because it is specifically designed to collect resource metrics (CPU and memory) from the kubelet on each node via the Summary API and expose them through the Kubernetes Metrics API. This allows tools like `kubectl top` and the Horizontal Pod Autoscaler to access real-time resource usage without requiring a full monitoring stack.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Prometheus Server
Why it's wrong here
Prometheus scrapes and stores time-series metrics, but the metrics API is served by metrics-server, which aggregates kubelet summaries; Prometheus does not populate it. Prometheus is tempting as the default Kubernetes monitoring tool, and would be correct if the question asked how metrics are collected and queried.
- ✗
Grafana
Why it's wrong here
Grafana queries and visualises metrics from data sources; it neither scrapes node metrics nor serves the metrics API. It is tempting because it is the familiar dashboard layer in Kubernetes monitoring stacks, and would be the answer if the question asked where metrics are graphed rather than aggregated.
- ✓
metrics-server
Why this is correct
metrics-server collects resource metrics from kubelets on each node, aggregates them, and serves them through the metrics API, which Horizontal Pod Autoscalers and kubectl top consume. It satisfies the requirement for node metric aggregation and API exposure.
- ✗
Fluentd
Why it's wrong here
Fluentd is a log collector and forwarder, handling neither metric aggregation nor the metrics API. It is tempting because it is a standard Kubernetes observability component, and would be the answer if the question concerned centralising container log output rather than exposing resource metrics.
Go deeper
Related to this question
About these practice questions
One of 930 original KCNA practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
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.