This KCNA practice question tests your understanding of container orchestration. Compare every option against the stated constraints before choosing — the best answer satisfies all requirements, not just the most obvious one. 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 Kubernetes cluster has a Deployment running three replicas of an application. You need to update the container image to a new version with zero downtime. Which approach is most appropriate?
Use 'kubectl set image deployment/<name> <container>=<new-image>' to trigger a rolling update
This command updates the image and initiates a rolling update, ensuring zero downtime.
B
Manually delete each pod and rely on the ReplicaSet to recreate them with the new image
Why wrong: Deleting pods does not automatically update the image; the ReplicaSet would create pods with the old image unless the Deployment template is updated first.
C
Delete the Deployment and recreate it with the new image
Why wrong: This would cause downtime as all pods are deleted before the new ones are created.
D
Scale the Deployment to zero and then scale back up with the new image
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use 'kubectl set image deployment/<name> <container>=<new-image>' to trigger a rolling update
Option A is correct because `kubectl set image deployment/<name> <container>=<new-image>` triggers a rolling update, which is the default update strategy for Deployments. This gradually replaces old pods with new ones, ensuring that the desired number of replicas is always available, thus achieving zero downtime.
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.
✓
Use 'kubectl set image deployment/<name> <container>=<new-image>' to trigger a rolling update
Why this is correct
This command updates the image and initiates a rolling update, ensuring zero downtime.
Related concept
Read the scenario before looking for a memorised answer.
✗
Manually delete each pod and rely on the ReplicaSet to recreate them with the new image
Why it's wrong here
Deleting pods does not automatically update the image; the ReplicaSet would create pods with the old image unless the Deployment template is updated first.
✗
Delete the Deployment and recreate it with the new image
Why it's wrong here
This would cause downtime as all pods are deleted before the new ones are created.
✗
Scale the Deployment to zero and then scale back up with the new image
Why it's wrong here
Scaling to zero would cause downtime.
Common exam traps
Common exam trap: answer the scenario, not the keyword
CNCF often tests the misconception that manually deleting pods or scaling to zero is a valid zero-downtime strategy, but these actions cause service disruption because they do not maintain the desired number of available replicas during the update.
Detailed technical explanation
How to think about this question
The rolling update strategy works by creating a new ReplicaSet with the updated pod template and gradually scaling it up while scaling down the old ReplicaSet. The `kubectl set image` command updates the Deployment's pod template, which triggers this process. The `kubectl rollout status` command can be used to monitor progress, and `kubectl rollout undo` can roll back if needed. In real-world scenarios, readiness probes are critical to ensure new pods are ready to serve traffic before old ones are terminated.
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 KCNA 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 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: Use 'kubectl set image deployment/<name> <container>=<new-image>' to trigger a rolling update — Option A is correct because `kubectl set image deployment/<name> <container>=<new-image>` triggers a rolling update, which is the default update strategy for Deployments. This gradually replaces old pods with new ones, ensuring that the desired number of replicas is always available, thus achieving zero downtime.
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.
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.