- A
containers: - name: app securityContext: runAsNonRoot: true volumeMounts: - mountPath: /tmp name: scratch volumes: - name: scratch emptyDir: {}
Why wrong: runAsNonRoot does not make filesystem read-only.
- B
containers: - name: app securityContext: readOnlyRootFilesystem: true volumeMounts: - mountPath: /tmp name: scratch volumes: - name: scratch emptyDir: {}
readOnlyRootFilesystem makes rootfs read-only; emptyDir provides writable tmpfs.
- C
containers: - name: app securityContext: readOnlyRootFilesystem: false
Why wrong: This allows writes to rootfs, not immutable.
- D
containers: - name: app securityContext: readOnlyRootFilesystem: true volumeMounts: - mountPath: /tmp name: scratch volumes: - name: scratch hostPath: path: /tmp
Why wrong: hostPath is not temporary and may have security implications.
Configuring readOnlyRootFilesystem with emptyDir for Temporary Writes
This CKS practice question tests your understanding of monitoring, logging and runtime security. 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.
You need to ensure a container's filesystem is immutable at runtime except for a temporary volume. Which Pod spec configuration achieves this?
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
containers: - name: app securityContext: readOnlyRootFilesystem: true volumeMounts: - mountPath: /tmp name: scratch volumes: - name: scratch emptyDir: {}
Option B is correct because setting `readOnlyRootFilesystem: true` in the container's securityContext makes the container's filesystem immutable at runtime, preventing any writes to the root filesystem. By mounting an `emptyDir` volume at `/tmp`, the container gets a writable temporary volume for scratch data, satisfying the requirement of a temporary writable area while keeping the rest of the filesystem read-only.
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.
- ✗
containers: - name: app securityContext: runAsNonRoot: true volumeMounts: - mountPath: /tmp name: scratch volumes: - name: scratch emptyDir: {}
Why it's wrong here
runAsNonRoot does not make filesystem read-only.
- ✓
containers: - name: app securityContext: readOnlyRootFilesystem: true volumeMounts: - mountPath: /tmp name: scratch volumes: - name: scratch emptyDir: {}
Why this is correct
readOnlyRootFilesystem makes rootfs read-only; emptyDir provides writable tmpfs.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
containers: - name: app securityContext: readOnlyRootFilesystem: false
Why it's wrong here
This allows writes to rootfs, not immutable.
- ✗
containers: - name: app securityContext: readOnlyRootFilesystem: true volumeMounts: - mountPath: /tmp name: scratch volumes: - name: scratch hostPath: path: /tmp
Why it's wrong here
hostPath is not temporary and may have security implications.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The CKS exam often tests the distinction between `runAsNonRoot` and `readOnlyRootFilesystem`, where candidates mistakenly think `runAsNonRoot` provides filesystem immutability, or they overlook that `hostPath` volumes are not temporary and violate the requirement for a temporary volume.
Detailed technical explanation
How to think about this question
When `readOnlyRootFilesystem: true` is set, the container's root filesystem is mounted with the `MS_RDONLY` flag at the kernel level, preventing any write, create, or delete operations on the root filesystem. The `emptyDir` volume is created on the node's local storage (typically a tmpfs if backed by memory) and is ephemeral—it is deleted when the Pod is removed, making it ideal for temporary scratch space. In real-world scenarios, this pattern is critical for security-hardened containers (e.g., in PCI-DSS or SOC2 environments) to prevent attackers from modifying binaries or writing malicious files to the container image.
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.
- →
Monitoring, Logging and Runtime Security — study guide chapter
Learn the concepts, then practise the questions
- →
Monitoring, Logging and Runtime 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
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?
Monitoring, Logging and Runtime Security — This question tests Monitoring, Logging and Runtime Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: containers: - name: app securityContext: readOnlyRootFilesystem: true volumeMounts: - mountPath: /tmp name: scratch volumes: - name: scratch emptyDir: {} — Option B is correct because setting `readOnlyRootFilesystem: true` in the container's securityContext makes the container's filesystem immutable at runtime, preventing any writes to the root filesystem. By mounting an `emptyDir` volume at `/tmp`, the container gets a writable temporary volume for scratch data, satisfying the requirement of a temporary writable area while keeping the rest of the filesystem read-only.
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.