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Kubernetes FundamentalsmediumMultiple ChoiceObjective-mapped

KCNA Kubernetes Fundamentals Practice Question

Which component on a worker node is responsible for enforcing the network rules and implementing Service abstractions?

⚠ Common exam trap

A common misconception is that kubelet or the container runtime handles Service networking, but kube-proxy is the dedicated component for implementing network rules and Service abstractions on each node.

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

kube-proxy

kube-proxy is the component on each worker node that implements Service abstractions by maintaining network rules (iptables, IPVS, or userspace) that allow traffic to reach Pods from inside or outside the cluster. It watches the Kubernetes API server for changes to Services and EndpointSlices, then updates the node's packet filtering rules to forward traffic to the correct backend Pods, handling load balancing and session affinity.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • kube-proxy

    Why this is correct

    kube-proxy maintains network rules for Service connectivity.

  • kubelet

    Why it's wrong here

    kubelet manages containers on the node.

  • container runtime

    Why it's wrong here

    The runtime runs containers, not network rules.

  • kube-scheduler

    Why it's wrong here

    The scheduler runs on the control plane, not the worker node.

Visual reference

Source Router + ACL permit 10.0.0.0/8 deny any Server 10.0.0.5 ✓ 192.168.1.1 ✗ dropped ACLs evaluate top-down; first match wins — implicit deny all at end

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Same concept, more angles

1 more way this is tested on KCNA

These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.

Variation 1. Which component runs on every node and is responsible for maintaining network rules that allow communication to Pods from network endpoints?

medium
  • A.kube-controller-manager
  • B.kube-proxy
  • C.container runtime
  • D.kubelet

Why B: B is correct because kube-proxy is the component that runs on every node in a Kubernetes cluster and is responsible for maintaining network rules (e.g., iptables, IPVS, or userspace proxy) that allow network communication to Pods from network endpoints, both inside and outside the cluster. It implements the Kubernetes Service concept by managing the mapping of Service IPs to backend Pod IPs and performing load balancing.

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.