- A
spec.readOnlyRootFilesystem
Why wrong: The field is under securityContext, not directly under spec.
- B
securityContext.privileged: false
Why wrong: This disables privileged mode but does not enforce a read-only root filesystem.
- C
container.readOnly
Why wrong: There is no such field; the correct field is readOnlyRootFilesystem under securityContext.
- D
securityContext.readOnlyRootFilesystem
Correct. Setting this field to true enforces a read-only root filesystem for the container.
Question 731 of 997
Read-Only Root Filesystem
This CKS practice question tests your understanding of minimize microservice vulnerabilities. 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.
You need to ensure that all pods in a cluster run with read-only root filesystems. Which Pod Security Standard (PSS) control field should be set to true?
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
✓
securityContext.readOnlyRootFilesystem
Option D is correct because the Pod Security Standard (PSS) control field `securityContext.readOnlyRootFilesystem` must be set to `true` at the pod or container security context level to enforce a read-only root filesystem. This setting prevents containers from writing to their root filesystem, reducing the attack surface by limiting the ability to drop malicious binaries or modify system files. It is a key control under the 'Restricted' PSS profile for minimizing microservice vulnerabilities.
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.
- ✗
spec.readOnlyRootFilesystem
Why it's wrong here
The field is under securityContext, not directly under spec.
- ✗
securityContext.privileged: false
Why it's wrong here
This disables privileged mode but does not enforce a read-only root filesystem.
- ✗
container.readOnly
Why it's wrong here
There is no such field; the correct field is readOnlyRootFilesystem under securityContext.
- ✓
securityContext.readOnlyRootFilesystem
Why this is correct
Correct. Setting this field to true enforces a read-only root filesystem for the container.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The CKS exam often tests the distinction between pod-level and container-level security context fields, and candidates mistakenly look for a field under `spec` (like `spec.readOnlyRootFilesystem`) instead of the correct nested path `securityContext.readOnlyRootFilesystem` at the container level.
Detailed technical explanation
How to think about this question
The `readOnlyRootFilesystem` field, when set to `true`, mounts the container's root filesystem as read-only using the `MS_RDONLY` mount flag, preventing any writes to the overlay filesystem. However, containers can still write to volumes mounted via `emptyDir` or persistent volumes, so this control must be combined with volume restrictions for full immutability. In practice, this is often used with `securityContext.capabilities.drop: ['ALL']` and `runAsNonRoot: true` to achieve a 'Restricted' PSS profile.
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 junior network technician can log in to a core router but cannot reach the enable prompt or configuration mode. The AAA server is authenticating the login — but the authorisation policy only grants privilege level 1, not 15. Authentication (who you are) is working; authorisation (what you can do) is not.
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.
- →
Minimize Microservice Vulnerabilities — study guide chapter
Learn the concepts, then practise the questions
- →
Minimize Microservice Vulnerabilities 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
Related practice questions
Related CKS practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Monitoring Logging and Runtime Security practice questions
Practise CKS questions linked to Monitoring Logging and Runtime Security.
Cluster Setup and Hardening practice questions
Practise CKS questions linked to Cluster Setup and Hardening.
System Hardening practice questions
Practise CKS questions linked to System Hardening.
Minimize Microservice Vulnerabilities practice questions
Practise CKS questions linked to Minimize Microservice Vulnerabilities.
Supply Chain Security practice questions
Practise CKS questions linked to Supply Chain Security.
Monitoring, Logging and Runtime Security practice questions
Practise CKS questions linked to Monitoring, Logging and Runtime Security.
Cluster Setup practice questions
Practise CKS questions linked to Cluster Setup.
Cluster Hardening practice questions
Practise CKS questions linked to Cluster Hardening.
CKS fundamentals practice questions
Practise CKS questions linked to CKS fundamentals.
CKS scenario practice questions
Practise CKS questions linked to CKS scenario.
CKS troubleshooting practice questions
Practise CKS questions linked to CKS troubleshooting.
Practice this exam
Start a free CKS practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this CKS question test?
Minimize Microservice Vulnerabilities — This question tests Minimize Microservice Vulnerabilities — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: securityContext.readOnlyRootFilesystem — Option D is correct because the Pod Security Standard (PSS) control field `securityContext.readOnlyRootFilesystem` must be set to `true` at the pod or container security context level to enforce a read-only root filesystem. This setting prevents containers from writing to their root filesystem, reducing the attack surface by limiting the ability to drop malicious binaries or modify system files. It is a key control under the 'Restricted' PSS profile for minimizing microservice vulnerabilities.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
More CKS practice questions
- Which flag is used to restrict the kubelet's ability to modify node status and pods?
- A Falco rule has priority `WARNING` and output: `Sensitive file opened (user=%user.name command=%proc.cmdline file=%fd.n…
- Falco detects a shell being opened inside a container. Which Falco rule field is used to specify the syscall condition f…
- A security audit reveals that a ServiceAccount named 'monitor' has a ClusterRoleBinding to the cluster-admin role. What…
- Match each Kubernetes security component to its description.
- Match each Kubernetes certificate type to its usage.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.