This CKS practice question tests your understanding of system hardening. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 cluster has enabled the NodeRestriction admission controller. A developer is trying to create a pod with hostNetwork: true but is getting an error. What is the most likely reason?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The error is unrelated to NodeRestriction; the issue is likely a missing PodSecurityPolicy or Pod Security Admission that denies hostNetwork
The NodeRestriction admission controller only limits node self-updates to kubelet nodes, preventing them from modifying their own labels, taints, or other node objects. It does not block pods with `hostNetwork: true`. The error is most likely caused by a missing PodSecurityPolicy or Pod Security Admission (PSA) that denies pods with `hostNetwork: true`, as these are the mechanisms that enforce host namespace restrictions.
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.
✓
The error is unrelated to NodeRestriction; the issue is likely a missing PodSecurityPolicy or Pod Security Admission that denies hostNetwork
Why this is correct
NodeRestriction does not affect pod creation; the error likely comes from PSP/PSA.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The NodeRestriction admission controller blocks pods with hostNetwork
Why it's wrong here
NodeRestriction does not block hostNetwork; it restricts Node object modifications.
✗
The nodeSelector on the pod conflicts with NodeRestriction
Why it's wrong here
NodeRestriction does not affect nodeSelector.
✗
The developer lacks RBAC permissions to create pods
Why it's wrong here
RBAC is separate; the question states NodeRestriction is the context.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse NodeRestriction (which restricts kubelet node updates) with PodSecurityPolicy or Pod Security Admission (which restrict pod security contexts like hostNetwork), leading them to incorrectly attribute the error to NodeRestriction.
Detailed technical explanation
How to think about this question
NodeRestriction works by mutating or rejecting requests from kubelets to modify node objects, ensuring they can only change labels with a `node-restriction.kubernetes.io/` prefix and cannot modify taints or other node fields. In contrast, PodSecurityPolicy (deprecated in 1.21, removed in 1.25) or Pod Security Admission (the replacement) enforce host namespace settings like `hostNetwork` via the `privileged` or `host-namespaces` profiles. A real-world scenario is a cluster with PSA set to `restricted` in the namespace, which denies `hostNetwork: true` unless the pod explicitly opts into a higher privilege level.
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.
System Hardening — This question tests System Hardening — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The error is unrelated to NodeRestriction; the issue is likely a missing PodSecurityPolicy or Pod Security Admission that denies hostNetwork — The NodeRestriction admission controller only limits node self-updates to kubelet nodes, preventing them from modifying their own labels, taints, or other node objects. It does not block pods with `hostNetwork: true`. The error is most likely caused by a missing PodSecurityPolicy or Pod Security Admission (PSA) that denies pods with `hostNetwork: true`, as these are the mechanisms that enforce host namespace restrictions.
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.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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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