This KCNA practice question tests your understanding of container orchestration. 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 the Pending state. Running 'kubectl describe pod <pod-name>' shows the event: '0/3 nodes are available: 1 node had taint {node.kubernetes.io/disk-pressure: }, 2 nodes had taint {node.kubernetes.io/memory-pressure: }'. What is the most likely cause?
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
✓
All nodes have taints that the pod does not have tolerations for
The pod is stuck in Pending because the scheduler cannot find a node that satisfies its scheduling constraints. The events show that all three nodes have taints (disk-pressure and memory-pressure), and the pod does not have corresponding tolerations to allow it to be scheduled on those nodes. Without tolerations, the pod is not permitted to run on any of the available nodes, leaving it in 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.
✓
All nodes have taints that the pod does not have tolerations for
Why this is correct
The event indicates that each node has a taint (disk-pressure or memory-pressure) and the pod lacks corresponding 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 container image is not found in the registry
Why it's wrong here
Image pull issues would result in ErrImagePull or ImagePullBackOff, not Pending with taint events.
✗
The pod has a resource request that exceeds available capacity on all nodes
Why it's wrong here
While possible, the specific error message points to taints, not resource requests.
✗
The pod's liveness probe is failing
Why it's wrong here
Liveness probe failures occur after the pod is running, not during scheduling (Pending state).
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the distinction between taints/tolerations and resource constraints, where candidates mistakenly attribute a Pending state to resource exhaustion when the actual cause is missing tolerations for node taints.
Detailed technical explanation
How to think about this question
Taints and tolerations are a Kubernetes scheduling mechanism that restricts which pods can run on which nodes. Taints are applied to nodes (e.g., via `kubectl taint nodes`), and pods must have matching tolerations in their spec to be scheduled. The scheduler evaluates taints during the predicate phase; if no node has all taints tolerated, the pod remains Pending. This is distinct from resource-based scheduling, which uses the 'fit' algorithm to check requests against allocatable resources.
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 security administrator must allow nursing staff to reach a patient records server while blocking access from the guest Wi-Fi VLAN. After applying an extended ACL, traffic is still blocked from nursing workstations. The ACL was applied outbound instead of inbound on the wrong interface. Questions like this test ACL direction and placement rules.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this KCNA question in full detail.
Container Orchestration — This question tests Container Orchestration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: All nodes have taints that the pod does not have tolerations for — The pod is stuck in Pending because the scheduler cannot find a node that satisfies its scheduling constraints. The events show that all three nodes have taints (disk-pressure and memory-pressure), and the pod does not have corresponding tolerations to allow it to be scheduled on those nodes. Without tolerations, the pod is not permitted to run on any of the available nodes, leaving it in the Pending state.
What should I do if I get this KCNA 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 KCNA 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 KCNA 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.