Question 809 of 997
Supply Chain SecurityhardMultiple ChoiceObjective-mapped

CKS Supply Chain Security Practice Question

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?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "best"

    Why it matters: Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.

Question 1hardmultiple choice
Read the full NAT/PAT explanation →

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.

    Clue confirmation

    The clue word "best" in the question point toward this answer.

    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 small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.

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.

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.

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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.

Are there clue words in this question I should notice?

Yes — watch for: "best". Signals that multiple options may be partially correct. Choose the option that most directly solves the exact problem described, not the one that sounds most complete.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 30, 2026

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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.