This CKA practice question tests your understanding of workloads & scheduling. 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. The 'kubectl describe pod' output shows the event: '0/4 nodes are available: 3 node(s) had taint {node.kubernetes.io/unreachable: }, and 1 node(s) had taint {node.kubernetes.io/not-ready: }.' What is the most likely reason?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The pod does not have tolerations for the node taints
The pod is stuck in 'Pending' because none of the available nodes can schedule it. The events explicitly show taints: 'node.kubernetes.io/unreachable' on 3 nodes and 'node.kubernetes.io/not-ready' on 1 node. By default, pods do not tolerate these taints, so the scheduler cannot place the pod unless it has matching tolerations. Option B correctly identifies that the pod lacks the required tolerations.
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 has resource requests that exceed available capacity
Why it's wrong here
Resource insufficiency would show 'Insufficient memory' or 'Insufficient cpu' events, not taint-related messages.
✓
The pod does not have tolerations for the node taints
Why this is correct
The events explicitly mention taints, indicating missing tolerations.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The nodes are cordoned
Why it's wrong here
Cordoning would show 'node(s) cordoned' event.
✗
The kube-scheduler is not running
Why it's wrong here
If scheduler is down, no scheduling events would appear.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse taint-based scheduling failures with resource insufficiency or node cordoning, but the specific taint names in the event message directly point to node health issues rather than capacity or manual unschedulability.
Trap categories for this question
Command / output trap
Resource insufficiency would show 'Insufficient memory' or 'Insufficient cpu' events, not taint-related messages.
Detailed technical explanation
How to think about this question
Kubernetes taints and tolerations are a mechanism to control which pods can be scheduled on which nodes. The 'node.kubernetes.io/unreachable' taint is automatically added by the node controller when a node becomes unreachable (e.g., network partition), and 'node.kubernetes.io/not-ready' is added when the kubelet reports NotReady. By default, pods have no tolerations for these taints, so they are excluded from such nodes. In a real-world scenario, if a cluster experiences node failures, pods without tolerations will remain pending until the nodes recover or the taints are removed.
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 CKA 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 CKA question in full detail.
Workloads & Scheduling — This question tests Workloads & Scheduling — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The pod does not have tolerations for the node taints — The pod is stuck in 'Pending' because none of the available nodes can schedule it. The events explicitly show taints: 'node.kubernetes.io/unreachable' on 3 nodes and 'node.kubernetes.io/not-ready' on 1 node. By default, pods do not tolerate these taints, so the scheduler cannot place the pod unless it has matching tolerations. Option B correctly identifies that the pod lacks the required tolerations.
What should I do if I get this CKA 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This CKA 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 CKA exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.