CKAD Application Deployment Practice Question
Which TWO of the following are true about Kustomize overlays? (Select 2)
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
✓
Overlays are used to customize resources for different environments.
Option B is correct because Kustomize overlays exist precisely to adapt a shared base for distinct environments such as dev, staging, and prod, applying environment-specific settings without duplicating the base manifests. Option D is correct because overlays use patches (strategic merge patches, JSON 6902 patches, or JSON merge patches) to modify resources declared in the base, and they can also add new resources. Option A is wrong because overlays can both add and modify labels, for example via the labels and commonLabels fields, so they are not limited to additions. Option C is wrong because overlays are typically placed in separate directories that reference the base via a relative path in kustomization.yaml, not in the same directory. Option E is wrong because Kustomize works with plain Kubernetes YAML manifests and is not restricted to Helm charts.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Overlays can only add labels, not modify existing ones.
Why it's wrong here
Overlays apply strategic-merge and JSON 6902 patches, which can add, replace or delete any field, including existing labels. The misconception arises because common examples only append labels, and label-only addition would be correct where the base manifest is immutable and no field may be overwritten.
- ✓
Overlays are used to customize resources for different environments.
Why this is correct
Overlays layer environment-specific patches on top of a shared base, letting one set of manifests serve development, staging and production without duplication. This directly satisfies the stem's requirement that overlays customise resources per environment, since each overlay directory supplies only the differing values while inheriting the base.
- ✗
Overlays must be stored in the same directory as the base.
Why it's wrong here
Overlays reference bases by relative or absolute path, so they may sit in sibling or entirely separate directories, including separate repositories. Co-location is tempting because simple examples place both under one root, and that layout would be correct where a single repository holds the base and every environment overlay.
- ✓
Overlays can patch resources defined in a base.
Why this is correct
Overlays apply strategic-merge or JSON 6902 patches to resources inherited from a base, letting you customise them per environment without editing the originals. This satisfies the stem's requirement that overlays patch base-defined resources, since the base remains the single source of truth while overlays layer environment-specific changes on top.
- ✗
Overlays can only be used with Helm charts.
Why it's wrong here
Kustomize overlays are a native, chart-independent mechanism; they patch plain Kubernetes YAML bases and require no Helm release or templating. The confusion arises because Helm values files also customise deployments per environment, and Helm would be the right tool where packaging and release management across clusters is the actual requirement.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CKAD 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 CKAD exam.