This CKS practice question tests your understanding of system hardening. 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.
Network Topology
Given the exhibit, what will happen when a user creates a pod with an image from an untrusted registry?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The pod is created and the image is pulled
Option C is correct because, by default, Kubernetes does not enforce any restrictions on image registries. The kubelet will attempt to pull the image from any registry, including untrusted ones, unless an admission controller like ImagePolicyWebhook or a runtime-specific policy (e.g., containerd's `untrusted_workload` mode) is explicitly configured. In this scenario, no such policy is mentioned, so the pod is created and the image is pulled.
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.
✗
The pod is rejected by NodeRestriction admission
Why it's wrong here
NodeRestriction only restricts node kubelet actions.
✗
The pod is rejected by PodSecurity admission
Why it's wrong here
PodSecurity does not validate image registries.
✓
The pod is created and the image is pulled
Why this is correct
AlwaysPullImages forces image pull but does not block untrusted registries.
Related concept
Read the scenario before looking for a memorised answer.
✗
The pod is created but the image is not pulled because it's untrusted
Why it's wrong here
There is no mechanism to block untrusted registries in the given configuration.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the misconception that Kubernetes has a built-in 'untrusted registry' blocker, when in reality it requires explicit admission control or runtime configuration to enforce such policies.
Detailed technical explanation
How to think about this question
Under the hood, the kubelet's container runtime (e.g., containerd or CRI-O) handles image pulling via the CRI (Container Runtime Interface). To enforce trust, you would need to configure an ImagePolicyWebhook admission controller that queries an external service (e.g., Portieris or OPA) to evaluate registry signatures or policies. Alternatively, containerd's `untrusted_workload` runtime class can isolate untrusted images by running them in a separate runtime (e.g., gVisor or Kata Containers), but this does not block the pull itself.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CKS question in full detail.
System Hardening — This question tests System Hardening — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The pod is created and the image is pulled — Option C is correct because, by default, Kubernetes does not enforce any restrictions on image registries. The kubelet will attempt to pull the image from any registry, including untrusted ones, unless an admission controller like ImagePolicyWebhook or a runtime-specific policy (e.g., containerd's `untrusted_workload` mode) is explicitly configured. In this scenario, no such policy is mentioned, so the pod is created and the image is pulled.
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.
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Question Discussion
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