- A
Update the image tag in each Deployment's spec to point to the new patched image, then perform a rolling update. The admission controller will verify signatures and attestations for the new image.
This ensures all pods are updated with a verified, patched image in a controlled manner.
- B
SSH into each node, pull the new image, and use kubectl exec to update the library inside running containers.
Why wrong: This violates best practices, is error-prone, and changes are lost on restart.
- C
Temporarily disable the admission controller that verifies signatures and then update the image tags.
Why wrong: Disabling admission control weakens security; updates should be done with verification.
- D
Delete all running pods and let the ReplicaSets recreate them from the existing image.
Why wrong: The ReplicaSets still reference the old image; pods will be recreated with the vulnerable image.
How to Update Microservices with Patched Images While Preserving Signature Verification
This CKS practice question tests your understanding of supply chain security. 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 are the lead security engineer for a large financial institution. The organization runs a Kubernetes cluster with 500+ microservices. The supply chain security team has implemented the following measures: (1) All images are built from a minimal base image (distroless) and scanned with Trivy before being pushed to a private registry. (2) Images are signed using cosign with a key stored in a hardware security module (HSM). (3) Kyverno policies enforce that only signed images from the private registry can run, and also enforce that containers run as non-root. (4) A binary authorization (binauthz) style admission controller verifies attestations. Recently, a critical vulnerability (CVE-2024-0001) was discovered in a popular open-source library used by several microservices. The library is included as a dependency in the base image. The vulnerability is remotely exploitable and has a CVSS score of 9.8. The security team needs to remediate this quickly. They have already patched the library and updated the base image. What is the BEST course of action to ensure all running pods use the new image?
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
Update the image tag in each Deployment's spec to point to the new patched image, then perform a rolling update. The admission controller will verify signatures and attestations for the new image.
Option A is correct because updating the image tag in each Deployment triggers a rolling update, which creates new pods with the patched image. The admission controller (Kyverno) will verify the cosign signature and binary authorization attestation for the new image, ensuring supply chain security is maintained. This approach is the standard Kubernetes method for deploying image updates while preserving security controls.
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.
- ✓
Update the image tag in each Deployment's spec to point to the new patched image, then perform a rolling update. The admission controller will verify signatures and attestations for the new image.
Why this is correct
This ensures all pods are updated with a verified, patched image in a controlled manner.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
SSH into each node, pull the new image, and use kubectl exec to update the library inside running containers.
Why it's wrong here
This violates best practices, is error-prone, and changes are lost on restart.
- ✗
Temporarily disable the admission controller that verifies signatures and then update the image tags.
Why it's wrong here
Disabling admission control weakens security; updates should be done with verification.
- ✗
Delete all running pods and let the ReplicaSets recreate them from the existing image.
Why it's wrong here
The ReplicaSets still reference the old image; pods will be recreated with the vulnerable image.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the misconception that manual intervention (SSH, exec) or disabling security controls is acceptable for urgent fixes, when in fact the correct path is to update the deployment manifest and let Kubernetes orchestrate the change while keeping all security checks active.
Detailed technical explanation
How to think about this question
Cosign uses keyless signing or HSM-stored keys to produce a signature stored in an OCI registry alongside the image. Kyverno's verifyImages rule checks the signature against a trusted public key and can also validate attestations (e.g., from in-toto attestations) via binary authorization style checks. A rolling update (kubectl set image or patch) ensures zero-downtime deployment by gradually replacing pods, while the admission controller validates each new pod's image at creation time.
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.
- →
Supply Chain Security — study guide chapter
Learn the concepts, then practise the questions
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Supply Chain Security practice questions
Targeted practice on this topic area only
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Certified Kubernetes Security Specialist CKS study guide
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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: Update the image tag in each Deployment's spec to point to the new patched image, then perform a rolling update. The admission controller will verify signatures and attestations for the new image. — Option A is correct because updating the image tag in each Deployment triggers a rolling update, which creates new pods with the patched image. The admission controller (Kyverno) will verify the cosign signature and binary authorization attestation for the new image, ensuring supply chain security is maintained. This approach is the standard Kubernetes method for deploying image updates while preserving security controls.
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 →
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Last reviewed: Jun 30, 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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