This CKS practice question tests your understanding of supply chain security. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
A DevOps team wants to ensure that only signed images from a trusted registry are deployed in the cluster. They plan to use a webhook to intercept pod creation. Which tool is best suited for this task?
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.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Kyverno with a verifyImages rule
Kyverno is a Kubernetes-native policy engine that can enforce image signature verification via its `verifyImages` rule. It intercepts pod creation through a dynamic admission webhook, checking that container images are signed with a trusted key (e.g., using Sigstore/Cosign) before the pod is admitted. This directly meets the requirement to only allow signed images from a trusted registry.
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.
✗
kubectl with --validate flag
Why it's wrong here
kubectl does not enforce admission policies.
✗
Helm with signed charts
Why it's wrong here
Helm charts are for packaging, not runtime verification.
✗
etcd with encryption at rest
Why it's wrong here
etcd stores cluster data, not admission control.
✓
Kyverno with a verifyImages rule
Why this is correct
Kyverno supports image signature verification via cosign.
Clue confirmation
The clue word "best" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Prometheus with alerting rules
Why it's wrong here
Prometheus monitors metrics, not admission control.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse Helm chart signing (which verifies chart provenance) with container image signing, leading them to select Option B, even though Helm does not verify the images inside the chart at pod creation time.
Detailed technical explanation
How to think about this question
Kyverno's `verifyImages` rule leverages Cosign (part of the Sigstore project) to validate image signatures using public keys or keyless signing (e.g., Fulcio/OIDC). Under the hood, Kyverno acts as a MutatingAdmissionWebhook or ValidatingAdmissionWebhook, parsing the image reference and checking the signature against the specified trust root before the pod manifest is persisted. A subtle behavior is that Kyverno can also mutate images to ensure they come from a specific registry, adding an extra layer of supply chain security.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CKS question in full detail.
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: Kyverno with a verifyImages rule — Kyverno is a Kubernetes-native policy engine that can enforce image signature verification via its `verifyImages` rule. It intercepts pod creation through a dynamic admission webhook, checking that container images are signed with a trusted key (e.g., using Sigstore/Cosign) before the pod is admitted. This directly meets the requirement to only allow signed images from a trusted registry.
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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Question Discussion
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