KCNA Cloud Native Application Delivery Practice Question
A team uses Flux with the Source Controller and Kustomize Controller. They update a YAML file in Git to change a Deployment's replica count. What describes the synchronization flow?
⚠ Common exam trap
KCNA often tests the separation of responsibilities between Flux controllers, and candidates incorrectly assume the Source Controller applies manifests or that HelmReleases are used for Kustomize-based deployments.
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
✓
The Kustomize Controller fetches the source and applies the rendered manifests
In Flux's GitOps model, the Source Controller is responsible for fetching artifacts from sources like Git repositories, and the Kustomize Controller watches those sources, renders the Kustomize overlays, and applies the resulting manifests to the cluster. When a YAML file changes in Git, the Source Controller detects the new revision, and the Kustomize Controller reconciles the cluster to match the rendered output. This separation of concerns is core to Flux's controller architecture.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The Source Controller directly applies the manifest to the cluster
Why it's wrong here
The Source Controller only fetches and stores artefacts from Git; it never applies manifests to the cluster. It is tempting because it retrieves the updated YAML, but the Kustomize Controller performs the actual apply, so this omits the build-and-apply stage entirely.
- ✗
Flux uses HelmReleases to apply changes
Why it's wrong here
HelmReleases apply only when a HelmRelease custom resource and Helm Controller are present; this scenario uses Kustomize, not Helm. It is tempting because Helm is a common Flux integration, but the Kustomize Controller, not HelmRelease, renders and applies the updated manifest here.
- ✓
The Kustomize Controller fetches the source and applies the rendered manifests
Why this is correct
The Kustomize Controller reconciles the Kustomization custom resource, fetching the Git source through the Source Controller's artefact and applying the rendered manifests to the cluster. This satisfies the stem's requirement that a Git commit changing replica count propagates without manual intervention, since the Kustomize Controller owns the apply step rather than the Source Controller.
- ✗
Flux requires a manual kubectl apply to sync
Why it's wrong here
Flux's controllers continuously reconcile cluster state with Git automatically; no manual kubectl apply is involved. It is tempting because manual application gives explicit control, which suits teams avoiding automation, but it contradicts the GitOps reconciliation the question describes.
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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 CNCF exam blueprint
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.