KCNA Cloud Native Application Delivery Practice Question
When using Kustomize, how do you apply a common label to all resources in the base?
⚠ Common exam trap
Test-takers frequently confuse Kustomize's `patches` field with label application; candidates often assume any modification requires a patch, when `commonLabels` is the dedicated mechanism.
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
✓
By setting 'commonLabels' in the kustomization.yaml
Kustomize's `commonLabels` field in kustomization.yaml applies the specified labels to every resource rendered from the base, including selectors on Deployments and Services, without editing individual manifests. This is the idiomatic way to enforce consistent labeling across a set of resources.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
By editing each YAML file individually
Why it's wrong here
Editing each YAML file individually duplicates the label across manifests and defeats Kustomize's declarative overlay model, so drift appears as resources are added. It is tempting for small bases, but it is correct only when a manifest is managed outside any Kustomize base.
- ✓
By setting 'commonLabels' in the kustomization.yaml
Why this is correct
Setting `commonLabels` in `kustomization.yaml` makes Kustomize inject the specified labels into every resource's metadata during the build, satisfying the requirement to label all base resources uniformly. Kustomize applies this transformation automatically across the entire base, so no per-resource edits are needed.
- ✗
By using the 'patches' field to add labels
Why it's wrong here
The patches field applies targeted JSON6902 or strategic-merge edits to named resources; it does not propagate a label across every object in the base. It is tempting because patches do modify metadata, but it is correct when overriding specific fields on identified resources.
- ✗
By using a Helm chart instead of Kustomize
Why it's wrong here
Helm replaces Kustomize entirely, so the base's kustomization.yaml labels transformer is never applied. It is tempting because Helm also supports common labels, but it is correct when packaging templated charts rather than layering overlays onto an existing Kustomize base.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CNCF exam blueprint
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