- A
kubectl apply -f validatingwebhook.yaml where the webhook's service reference points to the gatekeeper-validating-webhook service.
Gatekeeper registers a ValidatingWebhookConfiguration that points to its service.
- B
kubectl apply -f constraint.yaml with a ConstraintTemplate.
Why wrong: ConstraintTemplate and Constraint are Gatekeeper custom resources, not the webhook itself.
- C
kubectl create validatingwebhook gatekeeper --from-file=webhook.yaml
Why wrong: kubectl does not have a create validatingwebhook command.
- D
kubectl run gatekeeper-webhook --image=openpolicyagent/gatekeeper:v3.14.0
Why wrong: This runs a pod but does not configure the webhook.
Question 309 of 997
How to Create a ValidatingWebhookConfiguration for OPA Gatekeeper
This CKS practice question tests your understanding of minimize microservice vulnerabilities. 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.
Which of the following commands creates a ValidatingWebhookConfiguration that uses an OPA Gatekeeper webhook?
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
✓
kubectl apply -f validatingwebhook.yaml where the webhook's service reference points to the gatekeeper-validating-webhook service.
Option A is correct because a ValidatingWebhookConfiguration in Kubernetes must reference a service that handles the admission review request. OPA Gatekeeper exposes its webhook via the `gatekeeper-validating-webhook` service, which listens for `AdmissionReview` requests on the `/v1/admit` endpoint. Applying a YAML manifest that correctly specifies this service reference in the `clientConfig.service` field creates the necessary webhook configuration to integrate Gatekeeper.
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 apply -f validatingwebhook.yaml where the webhook's service reference points to the gatekeeper-validating-webhook service.
Why this is correct
Gatekeeper registers a ValidatingWebhookConfiguration that points to its service.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
kubectl apply -f constraint.yaml with a ConstraintTemplate.
Why it's wrong here
ConstraintTemplate and Constraint are Gatekeeper custom resources, not the webhook itself.
- ✗
kubectl create validatingwebhook gatekeeper --from-file=webhook.yaml
Why it's wrong here
kubectl does not have a create validatingwebhook command.
- ✗
kubectl run gatekeeper-webhook --image=openpolicyagent/gatekeeper:v3.14.0
Why it's wrong here
This runs a pod but does not configure the webhook.
Common exam traps
Common exam trap: answer the scenario, not the keyword
This exam often tests the distinction between creating the Kubernetes resource that registers the webhook (ValidatingWebhookConfiguration) versus deploying the webhook server itself (Pod/Deployment), and candidates mistakenly think running the Gatekeeper container alone is sufficient to enable admission control.
Trap categories for this question
Command / output trap
kubectl does not have a create validatingwebhook command.
Detailed technical explanation
How to think about this question
Under the hood, a ValidatingWebhookConfiguration defines a `clientConfig` that can point to a Kubernetes service (via `service`) or an external URL (via `url`). Gatekeeper's webhook service typically runs on port 443 and handles `AdmissionReview` objects with `apiVersion: admission.k8s.io/v1`. A subtle behavior is that the `failurePolicy` field (defaulting to `Fail`) can cause cluster-wide admission failures if the webhook is unreachable, so in production it's often set to `Ignore` during initial deployment. Real-world scenarios include using multiple `rules` to scope the webhook to specific API groups or resources, preventing unnecessary calls to Gatekeeper for unrelated operations.
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.
- →
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: kubectl apply -f validatingwebhook.yaml where the webhook's service reference points to the gatekeeper-validating-webhook service. — Option A is correct because a ValidatingWebhookConfiguration in Kubernetes must reference a service that handles the admission review request. OPA Gatekeeper exposes its webhook via the `gatekeeper-validating-webhook` service, which listens for `AdmissionReview` requests on the `/v1/admit` endpoint. Applying a YAML manifest that correctly specifies this service reference in the `clientConfig.service` field creates the necessary webhook configuration to integrate Gatekeeper.
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
1 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 kubectl command would you use to create a ValidatingWebhookConfiguration from a YAML file?
easy- A.kubectl run webhook --image=webhook --restart=Never
- ✓ B.kubectl apply -f webhook.yaml
- C.kubectl create -f webhook.yaml
- D.kubectl expose deployment webhook --port=443
Why B: Option B is correct because `kubectl apply -f webhook.yaml` is the standard command to create or update Kubernetes resources from a YAML file, including a ValidatingWebhookConfiguration. This command uses declarative management, applying the configuration defined in the file to the cluster, which is the recommended approach for creating admission webhooks.
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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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