- A
kubectl edit deployment my-deployment
Why wrong: This opens an editor and is less efficient for a simple image update.
- B
kubectl apply -f updated-deployment.yaml
Why wrong: This also works but requires a YAML file; the set image command is more direct.
- C
kubectl patch deployment my-deployment -p '{"spec":{"template":{"spec":{"containers":[{"name":"nginx","image":"nginx:1.23"}]}}}}'
Why wrong: While this works, it is not the simplest or most common approach.
- D
kubectl set image deployment/my-deployment nginx=nginx:1.23
This command updates the image and initiates a rolling update.
Question 906 of 997
How to Update a Deployment's Container Image with Rolling Update
This KCNA practice question tests your understanding of kubernetes fundamentals. 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 developer needs to update a running Deployment's container image from 'nginx:1.21' to 'nginx:1.23' with minimal downtime and the ability to roll back if the new version fails. Which kubectl command should be used?
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
✓
kubectl set image deployment/my-deployment nginx=nginx:1.23
Option D is correct because `kubectl set image` directly updates the container image of a running Deployment, triggering a rolling update that replaces pods gradually to minimize downtime. This command also preserves the Deployment's rollout history, enabling a simple `kubectl rollout undo` to roll back if the new image fails.
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 edit deployment my-deployment
Why it's wrong here
This opens an editor and is less efficient for a simple image update.
- ✗
kubectl apply -f updated-deployment.yaml
Why it's wrong here
This also works but requires a YAML file; the set image command is more direct.
- ✗
kubectl patch deployment my-deployment -p '{"spec":{"template":{"spec":{"containers":[{"name":"nginx","image":"nginx:1.23"}]}}}}'
Why it's wrong here
While this works, it is not the simplest or most common approach.
- ✓
kubectl set image deployment/my-deployment nginx=nginx:1.23
Why this is correct
This command updates the image and initiates a rolling update.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
This question tests the misconception that any imperative command (like `edit` or `patch`) is equivalent for updating images, but the trap here is that `kubectl set image` is the simplest, most reliable imperative command specifically designed for this task, while other options introduce unnecessary complexity or risk of configuration drift.
Trap categories for this question
Command / output trap
This also works but requires a YAML file; the set image command is more direct.
Detailed technical explanation
How to think about this question
Under the hood, `kubectl set image` updates the Deployment's `spec.template.spec.containers[].image` field and increments the `spec.template.metadata.labels` hash, triggering a new ReplicaSet. The Deployment controller then performs a rolling update with configurable `maxSurge` and `maxUnavailable` parameters (default 25% each), ensuring minimal downtime. In a real-world scenario, if the new image has a critical bug, `kubectl rollout undo deployment/my-deployment` reverts to the previous ReplicaSet, restoring the old image and pod template.
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.
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.
- →
Kubernetes Fundamentals — study guide chapter
Learn the concepts, then practise the questions
- →
Kubernetes Fundamentals practice questions
Targeted practice on this topic area only
- →
All KCNA questions
997 questions across all exam domains
- →
Kubernetes and Cloud Native Associate KCNA study guide
Full concept coverage aligned to exam objectives
- →
KCNA practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related KCNA practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Kubernetes Fundamentals practice questions
Practise KCNA questions linked to Kubernetes Fundamentals.
Container Orchestration practice questions
Practise KCNA questions linked to Container Orchestration.
Cloud Native Architecture practice questions
Practise KCNA questions linked to Cloud Native Architecture.
Cloud Native Observability practice questions
Practise KCNA questions linked to Cloud Native Observability.
Cloud Native Application Delivery practice questions
Practise KCNA questions linked to Cloud Native Application Delivery.
KCNA fundamentals practice questions
Practise KCNA questions linked to KCNA fundamentals.
KCNA scenario practice questions
Practise KCNA questions linked to KCNA scenario.
KCNA troubleshooting practice questions
Practise KCNA questions linked to KCNA troubleshooting.
Practice this exam
Start a free KCNA practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this KCNA question test?
Kubernetes Fundamentals — This question tests Kubernetes Fundamentals — 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/my-deployment nginx=nginx:1.23 — Option D is correct because `kubectl set image` directly updates the container image of a running Deployment, triggering a rolling update that replaces pods gradually to minimize downtime. This command also preserves the Deployment's rollout history, enabling a simple `kubectl rollout undo` to roll back if the new image fails.
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 →
Same concept, more angles
4 more ways this is tested on KCNA
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. You need to update a Deployment's container image from nginx:1.14 to nginx:1.16 and ensure zero downtime. Which kubectl command should you use?
medium- ✓ A.kubectl set image deployment/my-deployment nginx=nginx:1.16
- B.kubectl patch deployment my-deployment -p '{"spec":{"template":{"spec":{"containers":[{"name":"nginx","image":"nginx:1.16"}]}}}}'
- C.kubectl edit deployment my-deployment --image=nginx:1.16
- D.kubectl update deployment my-deployment --image=nginx:1.16
Why A: Option A is correct because `kubectl set image` directly updates the container image in the Deployment's pod template, triggering a rolling update. Kubernetes Deployments handle zero-downtime updates by default via a rolling update strategy, which gradually replaces old pods with new ones while keeping the service available.
Variation 2. You want to update a Deployment's container image from 'nginx:1.20' to 'nginx:1.21' and record the change. Which kubectl command should you use?
medium- A.kubectl edit deployment nginx
- B.kubectl apply -f deployment.yaml
- ✓ C.kubectl set image deployment/nginx nginx=nginx:1.21 --record
- D.kubectl set image deployment/nginx nginx=nginx:1.21
Why C: Option C is correct because the `kubectl set image` command directly updates the container image of a specified deployment, and the `--record` flag annotates the change in the rollout history, allowing you to track the change for auditing or rollback purposes. This is the most efficient way to update the image and record the change without editing the full deployment manifest or reapplying a file.
Variation 3. You need to update a running Deployment to use a new container image. Which kubectl command should you use?
medium- A.kubectl replace -f deployment.yaml
- ✓ B.kubectl set image deployment/<name> <container>=<new-image>
- C.kubectl edit deployment <name>
- D.kubectl patch deployment <name> -p '{"spec":{"template":{"spec":{"containers":[{"name":"<container>","image":"<new-image>"}]}}}}'
Why B: Option B is correct because `kubectl set image` is the dedicated command for updating the container image of a running Deployment without modifying the entire manifest. It directly updates the Deployment's pod template spec, triggering a rolling update to replace pods with the new image.
Variation 4. You want to update a Deployment's container image to v2 and perform a rolling update. Which kubectl command achieves this?
medium- A.kubectl update deployment my-deployment --image=myapp:v2
- B.kubectl replace -f updated-deployment.yaml
- C.kubectl patch deployment my-deployment -p '{"spec":{"template":{"spec":{"containers":[{"name":"my-container","image":"myapp:v2"}]}}}}'
- ✓ D.kubectl set image deployment/my-deployment my-container=myapp:v2 --record
Why D: Option D is correct because `kubectl set image` is the standard imperative command to update a container image in a Deployment and triggers a rolling update automatically. Options A uses an invalid `kubectl update` command. Option B (`kubectl replace`) requires a full updated YAML file and triggers a rollout, but it is a declarative approach that is not the direct answer to the question asking for a single command. Option C (`kubectl patch`) can also work, but it is more complex and error-prone, requiring a JSON patch; the question asks for the command that achieves this, and D is the simplest and intended command.
Keep practising
More KCNA practice questions
- Which CNCF project provides a graduated service mesh implementation that includes features like traffic management, secu…
- A pod in the 'production' namespace is in a CrashLoopBackOff state. The pod has been running successfully for several da…
- You need to ensure that a pod runs on a node with SSD storage. How can you achieve this?
- Match each Kubernetes resource to its primary purpose.
- Match each Kubernetes security concept to its definition.
- Which three of the following are valid methods to create or update resources in Kubernetes? (Choose three.)
Last reviewed: Jul 4, 2026
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.