- A
ServiceAccount
Why wrong: Not an admission controller.
- B
PodSecurity
PodSecurity enforce allows setting profiles with predefined restrictions including read-only root filesystem.
- C
MutatingAdmissionWebhook
Why wrong: Would require custom code, not built-in.
- D
ImagePolicyWebhook
Why wrong: ImagePolicyWebhook deals with image registries, not pod security contexts.
Question 405 of 997
Read-Only Root Filesystem — PodSecurity Admission Controller
This CKS practice question tests your understanding of supply chain security. 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.
An administrator wants to enforce that all pods run with read-only root filesystem. Which admission controller can achieve this without writing custom code?
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
✓
PodSecurity
Option B is correct because the PodSecurity admission controller enforces the Pod Security Standards (PSS), which include a policy to restrict pods to a read-only root filesystem. Specifically, the 'Restricted' profile sets `readOnlyRootFilesystem: true` as a required field, preventing pods from writing to their root filesystem without custom code.
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.
- ✗
ServiceAccount
Why it's wrong here
Not an admission controller.
- ✓
PodSecurity
Why this is correct
PodSecurity enforce allows setting profiles with predefined restrictions including read-only root filesystem.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
MutatingAdmissionWebhook
Why it's wrong here
Would require custom code, not built-in.
- ✗
ImagePolicyWebhook
Why it's wrong here
ImagePolicyWebhook deals with image registries, not pod security contexts.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The CKS exam often tests the distinction between built-in admission controllers (like PodSecurity) and webhook-based controllers (like MutatingAdmissionWebhook) that require custom code, leading candidates to mistakenly choose the webhook option when the question explicitly prohibits custom code.
Detailed technical explanation
How to think about this question
The PodSecurity admission controller replaces the deprecated PodSecurityPolicy (PSP) and evaluates pods against three profiles (Privileged, Baseline, Restricted) defined in the Kubernetes documentation. The 'Restricted' profile enforces `readOnlyRootFilesystem: true` as a mandatory field, and the controller can be configured in warn, audit, or enforce mode via namespace labels like `pod-security.kubernetes.io/enforce: restricted`. Under the hood, it validates the pod spec against a set of predefined checks during admission, rejecting non-compliant pods without custom code.
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.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Supply Chain Security — study guide chapter
Learn the concepts, then practise the questions
- →
Supply Chain Security practice questions
Targeted practice on this topic area only
- →
All CKS questions
997 questions across all exam domains
- →
Certified Kubernetes Security Specialist CKS study guide
Full concept coverage aligned to exam objectives
- →
CKS practice test guide
How to use practice tests most effectively before exam day
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FAQ
Questions learners often ask
What does this CKS question test?
Supply Chain Security — This question tests Supply Chain Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: PodSecurity — Option B is correct because the PodSecurity admission controller enforces the Pod Security Standards (PSS), which include a policy to restrict pods to a read-only root filesystem. Specifically, the 'Restricted' profile sets `readOnlyRootFilesystem: true` as a required field, preventing pods from writing to their root filesystem without custom code.
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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Last reviewed: Jul 4, 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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