This KCNA practice question tests your understanding of container orchestration. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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 DevOps engineer wants to update a Deployment's container image from 'v1' to 'v2' with zero downtime. Which kubectl command should they use?
Why wrong: This also works but is more complex; however, the question asks for the 'most appropriate' command, and kubectl set image is simpler and standard.
C
kubectl set image deployment/<name> <container>=<image>:v2
This command triggers a rolling update, which by default updates pods gradually with zero downtime.
D
kubectl edit deployment <name>
Why wrong: This opens an editor but does not guarantee zero downtime if the user makes incorrect changes.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
kubectl set image deployment/<name> <container>=<image>:v2
Option C is correct because `kubectl set image` directly updates the container image in a Deployment's pod template, triggering a rolling update that replaces pods incrementally with zero downtime. Kubernetes Deployments manage ReplicaSets to ensure availability during the update, making this the simplest and most reliable command for a controlled image change.
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 rollout restart deployment/<name>
Why it's wrong here
This restarts pods with the same image, not updating the image.
This also works but is more complex; however, the question asks for the 'most appropriate' command, and kubectl set image is simpler and standard.
✓
kubectl set image deployment/<name> <container>=<image>:v2
Why this is correct
This command triggers a rolling update, which by default updates pods gradually with zero downtime.
Related concept
Read the scenario before looking for a memorised answer.
✗
kubectl edit deployment <name>
Why it's wrong here
This opens an editor but does not guarantee zero downtime if the user makes incorrect changes.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse `kubectl rollout restart` (which only restarts pods with the same image) with `kubectl set image` (which actually changes the image), or assume that any command modifying the Deployment (like patch or edit) inherently provides zero downtime without considering the rolling update mechanism.
Trap categories for this question
Command / output trap
This also works but is more complex; however, the question asks for the 'most appropriate' command, and kubectl set image is simpler and standard.
Detailed technical explanation
How to think about this question
Under the hood, `kubectl set image` modifies the `spec.template.spec.containers[].image` field in the Deployment's manifest, which triggers the Deployment controller to create a new ReplicaSet with the updated image and gradually scale down the old ReplicaSet based on the `rollingUpdate` strategy (default: 25% max surge and 25% max unavailable). In real-world CI/CD pipelines, this command is often used with `--record` to annotate the change reason, and it respects the `minReadySeconds` and `progressDeadlineSeconds` settings to ensure the update completes without service disruption.
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
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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: kubectl set image deployment/<name> <container>=<image>:v2 — Option C is correct because `kubectl set image` directly updates the container image in a Deployment's pod template, triggering a rolling update that replaces pods incrementally with zero downtime. Kubernetes Deployments manage ReplicaSets to ensure availability during the update, making this the simplest and most reliable command for a controlled image change.
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.
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Question Discussion
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