CKA Practice Question: Cluster Architecture, Installation and Configuration
Which control plane component stores the entire cluster state?
⚠ Common exam trap
A common mix-up: candidates confuse the kube-apiserver as the storage layer because it is the only component that interacts with etcd, but the apiserver is merely a gateway and does not persist data itself.
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
✓
etcd
Etcd because it is the distributed key-value store that serves as the single source of truth for the entire cluster state, including all objects, configurations, and secrets. The kube-apiserver is the only component that directly interacts with etcd, but it does not store the state itself—it reads from and writes to etcd on behalf of other components.
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-controller-manager
Why it's wrong here
While the kube-controller-manager is a crucial control plane component, its primary role is to run controller processes that regulate the state of the cluster. It continuously monitors the shared state of the cluster through the apiserver and makes changes attempting to move the current state towards the desired state. It does not actually store any persistent state itself.
- ✗
kube-scheduler
Why it's wrong here
The kube-scheduler is responsible for detecting newly created pods that have no node assigned and selecting the optimal node for them to run on. It makes these scheduling decisions based on resource requirements, policy constraints, and affinity specifications. However, it relies entirely on the API server to read and write this state, possessing no storage capabilities of its own.
- ✗
kube-apiserver
Why it's wrong here
The kube-apiserver acts as the front end for the Kubernetes control plane, exposing the API and validating all incoming requests. Although all other components communicate with it to query or update cluster configuration, the API server is stateless. It does not persist the cluster state directly, instead delegating all storage operations to the backing datastore.
- ✓
etcd
Why this is correct
etcd is a strongly consistent, highly available, distributed key-value store used as Kubernetes' secure registry for all cluster data. Every single object, configuration, and status detail in the cluster is persisted within etcd. It serves as the single source of truth, ensuring that the cluster state can be reliably recovered in the event of a control plane failure.
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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.