Linux Foundation Updated KCNA Exam Questions and Answers by jay

To retrieve CPU and memory consumption for nodes or Pods, you use kubectl top, so C is correct. kubectl top nodes shows per-node resource usage, and kubectl top pods shows per-Pod (and optionally per-container) usage. This data comes from the Kubernetes resource metrics pipeline, most commonly metrics-server, which scrapes kubelet/cAdvisor stats and exposes them via the metrics.k8s.io API.

It’s important to recognize that kubectl top provides current resource usage snapshots, not long-term historical trending. For long-term metrics and alerting, clusters typically use Prometheus and related tooling. But for quick operational checks—“Is this Pod CPU-bound?” “Are nodes near memory saturation?”—kubectl top is the built-in day-to-day tool.

Option A (kubectl cluster-info) shows general cluster endpoints and info about control plane services, not resource usage. Option B (kubectl version) prints client/server version info. Option D (kubectl api-resources) lists resource types available in the cluster. None of those report CPU/memory usage.

In observability practice, kubectl top is often used during incidents to correlate symptoms with resource pressure. For example, if a node is high on memory, you might see Pods being OOMKilled or the kubelet evicting Pods under pressure. Similarly, sustained high CPU utilization might explain latency spikes or throttling if limits are set. Note that kubectl top requires metrics-server (or an equivalent provider) to be installed and functioning; otherwise it may return errors like “metrics not available.”

So, the correct command for retrieving node/Pod CPU and memory usage is kubectl top.

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Distributed tracing is implemented primarily at the application layer, so B is correct. The reason is simple: tracing is about capturing the end-to-end path of a request as it traverses services, libraries, queues, and databases. That “request context” (trace ID, span ID, baggage) must be created, propagated, and enriched as code executes. While infrastructure components (proxies, gateways, service meshes) can generate or augment trace spans, the fundamental unit of tracing is still tied to application operations (an HTTP handler, a gRPC call, a database query, a cache lookup).

In Kubernetes-based microservices, distributed tracing typically uses standards like OpenTelemetry for instrumentation and context propagation. Application frameworks emit spans for key operations, attach attributes (route, status code, tenant, retry count), and propagate context via headers (e.g., W3C Trace Context). This is what lets you reconstruct “Service A → Service B → Service C” for one user request and identify the slow or failing hop.

Why other layers are not the best answer:

Network focuses on packets/flows, but tracing is not a packet-capture problem; it’s a causal request-path problem across services.

Database spans are part of traces, but tracing is not “implemented in the database layer” overall; DB spans are one component.

Infrastructure provides the platform and can observe traffic, but without application context it can’t fully represent business operations (and many useful attributes live in app code).

So the correct layer for “where tracing is implemented” is the application layer—even when a mesh or proxy helps, it’s still describing application request execution across components.

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Dynamic provisioning is the Kubernetes mechanism where storage is created on-demand when a user creates a PersistentVolumeClaim (PVC) that references a StorageClass, so A is correct. In this model, the user does not need to pre-create a PersistentVolume (PV). Instead, the StorageClass points to a provisioner (typically a CSI driver) that knows how to create a volume in the underlying storage system (cloud disk, SAN, NAS, etc.). When the PVC is created with storageClassName: , Kubernetes triggers the provisioner to create a new volume and then binds the resulting PV to that PVC.

This is why option B is incorrect: you do not put a StorageClass “in the Pod YAML” to request provisioning. Pods reference PVCs, not StorageClasses directly. Option C is incorrect because the PVC does not need the Pod name; binding is done via the PVC itself. Option D describes static provisioning: an admin pre-creates PVs and users claim them by creating PVCs that match the PV (capacity, access modes, selectors). Static provisioning can work, but it is not dynamic provisioning.

Under the hood, the StorageClass can define parameters like volume type, replication, encryption, and binding behavior (e.g., volumeBindingMode: WaitForFirstConsumer to delay provisioning until the Pod is scheduled, ensuring the volume is created in the correct zone). Reclaim policies (Delete/Retain) define what happens to the underlying volume after the PVC is deleted.

In cloud-native operations, dynamic provisioning is preferred because it improves developer self-service, reduces manual admin work, and makes scaling stateful workloads easier and faster. The essence is: PVC + StorageClass → automatic PV creation and binding.

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The correct answer is C: Retain. In Kubernetes persistent storage, a PersistentVolume (PV) has a persistentVolumeReclaimPolicy that determines what happens to the underlying storage asset after its PersistentVolumeClaim (PVC) is deleted. The reclaim policy options historically include Delete and Retain (and Recycle, which is deprecated/removed in many modern contexts). “Manual reclamation” refers to the administrator having to manually clean up and/or rebind the storage after the claim is released—this behavior corresponds to Retain.

With Retain, when the PVC is deleted, the PV moves to a “Released” state, but the actual storage resource (cloud disk, NFS path, etc.) is not deleted automatically. Kubernetes will not automatically make that PV available for a new claim until an administrator takes action—typically cleaning the data, removing the old claim reference, and/or creating a new PV/PVC binding flow. This is important for data safety: you don’t want to automatically delete sensitive or valuable data just because a claim was removed.

By contrast, Delete means Kubernetes (via the storage provisioner/CSI driver) will delete the underlying storage asset when the claim is deleted—useful for dynamic provisioning and disposable environments. Recycle used to scrub the volume contents and make it available again, but it’s not the recommended modern approach and has been phased out in favor of dynamic provisioning and explicit workflows.

So, the policy that implies manual intervention and manual cleanup/reuse is Retain, which is option C.

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