This CKS practice question tests your understanding of cluster setup and hardening. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A security policy requires that all communication to etcd be encrypted. Which two components must be configured with TLS certificates to achieve this? (Select two)
kubelet
Why wrong: kubelet communicates with the API server.
kube-apiserver
The API server connects to etcd as a client.
kube-scheduler
Why wrong: kube-scheduler communicates with the API server.
kube-controller-manager
Why wrong: kube-controller-manager communicates with the API server, not directly with etcd.
etcd
etcd server presents a TLS certificate to clients.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
kube-apiserver
The kube-apiserver is the only Kubernetes control plane component that directly communicates with etcd. To encrypt this communication, TLS certificates must be configured on both the kube-apiserver (as the client) and etcd (as the server). The kube-apiserver presents its client certificate to etcd, and etcd presents its server certificate to the kube-apiserver, establishing a mutually authenticated TLS session.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
kubelet
Why it's wrong here
kubelet communicates with the API server.
kube-apiserver
Why this is correct
The API server connects to etcd as a client.
Related concept
Read the scenario before looking for a memorised answer.
kube-scheduler
Why it's wrong here
kube-scheduler communicates with the API server.
kube-controller-manager
Why it's wrong here
kube-controller-manager communicates with the API server, not directly with etcd.
etcd
Why this is correct
etcd server presents a TLS certificate to clients.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates often assume all control plane components (scheduler, controller-manager) communicate directly with etcd, but in reality only the kube-apiserver interacts with etcd, while the others only talk to the apiserver.
Detailed technical explanation
Under the hood, etcd supports both client-to-server and peer-to-peer TLS encryption. The kube-apiserver acts as an etcd client using the etcd v3 API over gRPC, which requires TLS mutual authentication if `--etcd-certfile` and `--etcd-keyfile` are specified on the apiserver and `--client-cert-auth` is enabled on etcd. A real-world scenario is when etcd is deployed externally to the cluster; misconfiguring these certificates can cause the apiserver to fail to start or silently fall back to unencrypted communication, violating the security policy.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the CKS exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Cluster Setup and Hardening — This question tests Cluster Setup and Hardening — Read the scenario before looking for a memorised answer..
The correct answer is: kube-apiserver — The kube-apiserver is the only Kubernetes control plane component that directly communicates with etcd. To encrypt this communication, TLS certificates must be configured on both the kube-apiserver (as the client) and etcd (as the server). The kube-apiserver presents its client certificate to etcd, and etcd presents its server certificate to the kube-apiserver, establishing a mutually authenticated TLS session.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 24, 2026
This CKS 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 CKS exam.
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