CKA Practice Question: Cluster Architecture, Installation and Configuration
Which component is responsible for running containers on a Kubernetes node?
⚠ Common exam trap
It's easy for candidates to confuse the kubelet with the kube-scheduler or kube-controller-manager, thinking that scheduling or managing controllers is equivalent to running containers, but the kubelet is the only component that directly interacts with the container runtime to execute containers on a 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
✓
kubelet
The kubelet is the primary node agent that runs on each Kubernetes node. It is responsible for ensuring that containers are running in a Pod as expected by interacting with the container runtime (e.g., Docker, containerd, CRI-O) via the Container Runtime Interface (CRI). It receives Pod specifications from the API server and manages the lifecycle of the containers accordingly.
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 it's wrong here
kube-proxy is a network proxy that maintains rules on nodes to handle Service traffic, using iptables or IPVS to route packets to backing pods. It doesn't interact with the container runtime or create any containers; its sole focus is network connectivity and load balancing. The kubelet remains the node agent that actually launches and manages the containers.
- ✗
kube-scheduler
Why it's wrong here
The kube-scheduler is a control-plane component that selects an appropriate node for pending pods based on resource requests, node affinity, taints, and tolerations, then writes a binding decision to the API server. Its work is purely logical and occurs before any container ever exists; it never invokes runtimes or executes processes. Therefore, it is not responsible for running containers on a node.
- ✓
kubelet
Why this is correct
The kubelet is the core node agent that takes PodSpecs from the API server or local manifests and uses the Container Runtime Interface to instruct a runtime such as containerd or CRI-O to pull images, create sandboxes, and start containers. It also monitors container health, enforces pod resources, and reports status back to the control plane. Because it is the component that directly drives the runtime, the kubelet is responsible for running containers.
- ✗
kube-controller-manager
Why it's wrong here
The kube-controller-manager bundles control loops such as ReplicationManager and DeploymentController that reconcile desired state by creating or deleting Pod objects through the API server. These controllers never open a socket or start a process on any node; they only mutate the cluster's desired state. Actual container execution is delegated from the API server to the kubelet, making the controller manager only an indirect orchestrator.
Go deeper
Related to this question
Learn chapter
Kubernetes Architecture Overview
Key term
Container Runtime
A container runtime is software that runs containers by using the host operating system's kernel to isolate processes, manage filesystem layers, and handle networking.
Key term
Ingress Resources
Ingress Resources are Kubernetes API objects that manage external access to services inside a cluster, typically HTTP and HTTPS traffic, by defining rules for routing requests based on hostnames and paths.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CKA 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 CKA exam.