- A
kubectl taint nodes control-plane node-role.kubernetes.io/control-plane-
Why wrong: This removes the taint, which may be undesirable for security.
- B
kubectl cordon control-plane
Why wrong: Cordoning marks a node as unschedulable, which would not help.
- C
Edit the pod YAML to add tolerations for node-role.kubernetes.io/control-plane
Adding the appropriate toleration allows the pod to schedule on tainted nodes.
- D
kubectl delete pod --all
Why wrong: Deleting pods does not resolve scheduling constraints.
Question 667 of 997
Resolve Pod Pending Due to Control-Plane Taint with Tolerations
This CKS practice question tests your understanding of supply chain security. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 pod is stuck in Pending state. 'kubectl describe pod' shows the event: '0/4 nodes are available: 1 node had taint {node-role.kubernetes.io/control-plane: }, that the pod didn't tolerate, 3 Insufficient memory.' The pod YAML does not specify any tolerations. Which command would allow the pod to schedule on the control-plane node?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"which command"Why it matters: Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
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
✓
Edit the pod YAML to add tolerations for node-role.kubernetes.io/control-plane
Option C is correct because the pod is failing to schedule on the control-plane node due to the `node-role.kubernetes.io/control-plane` taint, which by default prevents pods without a matching toleration from being scheduled. Since the pod YAML does not specify any tolerations, editing it to add a toleration for that taint (e.g., `tolerations: - key: node-role.kubernetes.io/control-plane operator: Exists`) explicitly allows the pod to run on the control-plane node, resolving the Pending state.
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 taint nodes control-plane node-role.kubernetes.io/control-plane-
Why it's wrong here
This removes the taint, which may be undesirable for security.
- ✗
kubectl cordon control-plane
Why it's wrong here
Cordoning marks a node as unschedulable, which would not help.
- ✓
Edit the pod YAML to add tolerations for node-role.kubernetes.io/control-plane
Why this is correct
Adding the appropriate toleration allows the pod to schedule on tainted nodes.
Clue confirmation
The clue word "which command" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
kubectl delete pod --all
Why it's wrong here
Deleting pods does not resolve scheduling constraints.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose to remove the taint (Option A) because it seems like a quick fix, but the CKS exam emphasizes security best practices—taints are a security mechanism to isolate control-plane components, and removing them globally is insecure and unnecessary when a toleration can be added to the specific pod.
Detailed technical explanation
How to think about this question
Taints and tolerations work as a scheduling constraint: a taint on a node (e.g., `node-role.kubernetes.io/control-plane:NoSchedule`) repels pods that do not have a matching toleration. The `kube-scheduler` evaluates taints during the filtering phase; if a pod lacks the toleration, the node is marked as unfit. In production, control-plane nodes are intentionally tainted to prevent user workloads from running on them, so adding a toleration to a specific pod (rather than removing the taint) is the targeted and secure approach.
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.
Visual reference
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
- →
Supply Chain Security practice questions
Targeted practice on this topic area only
- →
All CKS questions
997 questions across all exam domains
- →
Certified Kubernetes Security Specialist CKS study guide
Full concept coverage aligned to exam objectives
- →
CKS practice test 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: Edit the pod YAML to add tolerations for node-role.kubernetes.io/control-plane — Option C is correct because the pod is failing to schedule on the control-plane node due to the `node-role.kubernetes.io/control-plane` taint, which by default prevents pods without a matching toleration from being scheduled. Since the pod YAML does not specify any tolerations, editing it to add a toleration for that taint (e.g., `tolerations: - key: node-role.kubernetes.io/control-plane operator: Exists`) explicitly allows the pod to run on the control-plane node, resolving the Pending state.
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: "which command". Tests specific CLI syntax. Recall the exact command and its required context — near-synonyms and partial matches are common distractors.
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: 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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