Google ACE Practice Question: Ensuring Successful Operation of a Cloud Solution
You notice that a deployment in your GKE cluster is running an outdated image. You need to update the deployment to use the new image 'gcr.io/my-project/my-app:v2'. Which kubectl command should you use?
⚠ Common exam trap
The trap is confusing commands that sound similar: 'kubectl set image' is the correct one, but candidates might choose 'rollout restart' thinking it updates the image, or 'replace' thinking it's a general update command.
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 my-app=gcr.io/my-project/my-app:v2
The correct command to update a deployment's container image is 'kubectl set image', which updates the image for a specific container within the deployment. The syntax 'deployment/my-deployment my-app=gcr.io/my-project/my-app:v2' specifies the deployment name and the container name with the new image. This triggers a rolling update.
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 set image deployment/my-deployment my-app=gcr.io/my-project/my-app:v2
Why this is correct
kubectl set image deployment/my-deployment my-app=gcr.io/my-project/my-app:v2 is the correct imperative command to update a container image inside a Deployment. The container name (my-app) must exactly match the container name defined in the Deployment's pod spec, and the command updates the pod template so the Deployment controller creates a new ReplicaSet and performs a rolling update. This is the canonical kubectl syntax for changing an image without editing a manifest.
- ✗
kubectl rollout restart deployment my-deployment --image gcr.io/my-project/my-app:v2
Why it's wrong here
kubectl rollout restart deployment my-deployment --image gcr.io/my-project/my-app:v2 is invalid and conceptually wrong: the rollout restart subcommand does not support an --image flag, and even without that flag it would only add an annotation to trigger a new ReplicaSet using the existing pod template image. It is useful for restarting pods to re-pull the same image or re-read ConfigMaps, but it cannot change the container image to v2. Use kubectl set image to actually update the image.
- ✗
kubectl update deployment my-deployment --image gcr.io/my-project/my-app:v2
Why it's wrong here
kubectl update deployment my-deployment --image gcr.io/my-project/my-app:v2 is incorrect because kubectl update is not a valid subcommand; kubectl uses edit, apply, patch, replace, and set to modify resources. This command would fail with an unknown command error, and even if a hypothetical update subcommand existed, the --image flag is not part of its syntax. The correct imperative image update is kubectl set image deployment/my-deployment my-app=<new-image>.
- ✗
kubectl replace deployment my-deployment --image gcr.io/my-project/my-app:v2
Why it's wrong here
kubectl replace deployment my-deployment --image gcr.io/my-project/my-app:v2 is wrong because kubectl replace requires a YAML/JSON manifest file passed with -f and does not accept an --image flag; it overwrites the entire existing resource definition with the specified file contents. This command would fail with an unknown flag error and would not perform an incremental image update. A proper kubectl replace -f deployments.yaml would require the file to already contain the new image, making it a declarative replacement, not a simple image update.
Go deeper
Related to this question
Learn chapter
Shared VPC for Multi-Project Networking
Key term
GKE
GKE is Google's managed Kubernetes service that automates deploying, scaling, and managing containerized applications in the cloud.
Key term
Container
A container is a lightweight, standalone software package that includes everything needed to run an application, such as code, runtime, system tools, and libraries.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Google Cloud exam blueprint
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