This CKS practice question tests your understanding of cluster setup and hardening. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Which TWO of the following are valid methods to restrict etcd access? (Choose two.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use TLS client certificates for authentication
Option B is correct because etcd supports mutual TLS (mTLS) authentication, where the client (e.g., kube-apiserver) presents a client certificate signed by the etcd CA. This ensures that only authenticated clients can communicate with etcd, effectively restricting access. Option C is correct because etcd has its own Role-Based Access Control (RBAC) system, which can be enabled to restrict read/write operations to specific users or roles, providing fine-grained access control.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Use firewall rules to restrict access to etcd port 2379
Why it's wrong here
While helpful, this is not an etcd-specific access control; it's network-level.
✓
Use TLS client certificates for authentication
Why this is correct
TLS client certificates authenticate clients to etcd.
Related concept
Read the scenario before looking for a memorised answer.
✓
Enable etcd RBAC
Why this is correct
etcd RBAC provides fine-grained access control.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use etcd's built-in password authentication
Why it's wrong here
etcd does not support password authentication.
✗
Set the --etcd-certfile flag on kube-apiserver
Why it's wrong here
This flag is for API server to present a certificate to etcd, not for restricting access.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse network-level controls (firewall rules) or API server flags with actual etcd authentication/authorization mechanisms, or mistakenly believe etcd supports password authentication like traditional databases.
Detailed technical explanation
How to think about this question
etcd's mTLS authentication uses X.509 certificates, where the server verifies the client certificate against a trusted CA, and optionally the client verifies the server certificate. etcd RBAC is implemented via etcd's v3 API, where roles and users are managed using etcdctl commands (e.g., etcdctl user add, etcdctl role grant-permission). In production, both mTLS and RBAC are often combined for defense-in-depth: mTLS authenticates the client, and RBAC authorizes specific operations (e.g., read-only access to /registry/secrets).
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CKS question in full detail.
Cluster Setup and Hardening — This question tests Cluster Setup and Hardening — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use TLS client certificates for authentication — Option B is correct because etcd supports mutual TLS (mTLS) authentication, where the client (e.g., kube-apiserver) presents a client certificate signed by the etcd CA. This ensures that only authenticated clients can communicate with etcd, effectively restricting access. Option C is correct because etcd has its own Role-Based Access Control (RBAC) system, which can be enabled to restrict read/write operations to specific users or roles, providing fine-grained access control.
What should I do if I get this CKS question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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