- A
Set the container image to use a root user
Why wrong: This would run as root.
- B
Set runAsNonRoot: true in the pod securityContext
This enforces that the container cannot run as root.
- C
Use a PodSecurityPolicy (PSP)
Why wrong: PSP is deprecated and removed in v1.25; not a valid current method.
- D
Use a Kyverno policy to validate runAsNonRoot
Kyverno can enforce policies for non-root.
- E
Set runAsUser: 0 in the container securityContext
Why wrong: This runs as root (uid 0).
Question 111 of 997
How to Enforce a Container Runs as Non-Root: runAsNonRoot, Kyverno, and More
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.
Which TWO of the following are valid ways to enforce that a container runs as a non-root user?
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
✓
Set runAsNonRoot: true in the pod securityContext
Option B is correct because setting `runAsNonRoot: true` in the pod's `securityContext` explicitly instructs the kubelet to validate that the container's user ID is not 0 (root) before starting the container. If the container attempts to run as root, the kubelet will refuse to start it, providing a strong enforcement mechanism at the Kubernetes level.
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.
- ✗
Set the container image to use a root user
Why it's wrong here
This would run as root.
- ✓
Set runAsNonRoot: true in the pod securityContext
Why this is correct
This enforces that the container cannot run as root.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Use a PodSecurityPolicy (PSP)
Why it's wrong here
PSP is deprecated and removed in v1.25; not a valid current method.
- ✓
Use a Kyverno policy to validate runAsNonRoot
Why this is correct
Kyverno can enforce policies for non-root.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Set runAsUser: 0 in the container securityContext
Why it's wrong here
This runs as root (uid 0).
Common exam traps
Common exam trap: answer the scenario, not the keyword
The CKS exam often tests the misconception that PodSecurityPolicy (PSP) is still a valid option, but it has been removed since Kubernetes v1.25, so candidates must know that Kyverno or OPA/Gatekeeper policies are the modern replacements for enforcing non-root execution.
Detailed technical explanation
How to think about this question
Under the hood, `runAsNonRoot: true` leverages the container runtime's user namespace capabilities and the kubelet's admission control to check the container's configured user ID against the image's default user. If the image specifies a user with UID 0 or no user is set (defaulting to root), the kubelet will fail the pod creation with an event like 'container has runAsNonRoot and image will run as root'. This is critical in multi-tenant clusters where a compromised container could otherwise escape to the host.
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.
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Minimize Microservice Vulnerabilities — study guide chapter
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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: Set runAsNonRoot: true in the pod securityContext — Option B is correct because setting `runAsNonRoot: true` in the pod's `securityContext` explicitly instructs the kubelet to validate that the container's user ID is not 0 (root) before starting the container. If the container attempts to run as root, the kubelet will refuse to start it, providing a strong enforcement mechanism at the Kubernetes level.
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 →
Same concept, more angles
2 more ways this is tested on CKS
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which field must be set in a Pod's security context to prevent the container from running as the root user?
easy- A.runAsUser: 1000
- B.readOnlyRootFilesystem: true
- C.allowPrivilegeEscalation: false
- ✓ D.runAsNonRoot: true
Why D: The `runAsNonRoot: true` field in a Pod's security context enforces that the container's entrypoint cannot run as UID 0 (root). If the container image attempts to run as root, the container runtime (e.g., containerd) will reject the container from starting, ensuring compliance with the principle of least privilege and mitigating root-based container escapes.
Variation 2. Which TWO of the following are valid Pod Security Context settings to harden a container? (Select 2)
medium- A.privileged: true
- B.runAsUser: 0
- ✓ C.runAsNonRoot: true
- ✓ D.readOnlyRootFilesystem: true
- E.allowPrivilegeEscalation: true
Why C: Option C is correct because setting `runAsNonRoot: true` in the Pod Security Context forces the container to run with a user ID (UID) other than 0 (root). This is a fundamental hardening measure that prevents an attacker who gains code execution inside the container from having root privileges, thereby limiting the blast radius of a compromise. It is a recommended practice in the CIS Benchmark for Kubernetes and directly addresses the principle of least privilege.
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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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