KCNA Practice Test 26 — 15 Questions

Question 1

A Deployment is configured with 'replicas: 3'. After a node failure, only 2 pods are running. What component ensures that a new pod is scheduled to restore the desired replica count?

Accepted Answer

kube-controller-manager. The kube-controller-manager runs the ReplicaSet controller, which detects the mismatch and creates a new pod.

Answer

kube-scheduler

Answer

kubelet

Answer

kube-proxy

Question 2

You have a Deployment with three replicas. You want to update the container image but ensure that only one pod is updated at a time, and the update proceeds only if the new pod becomes healthy. Which update strategy should you configure?

Accepted Answer

RollingUpdate with maxSurge=1 and maxUnavailable=0. A RollingUpdate strategy with maxSurge=1 and maxUnavailable=0 ensures that exactly one new pod is created before any old pod is terminated, and the update only proceeds when the new pod passes its readiness probe (i.e., becomes healthy). This guarantees that at all times during the update, the desired number of replicas (3) are available, and only one pod is updated at a time, matching the requirement.

Answer

RollingUpdate with maxSurge=3 and maxUnavailable=1

Answer

Canary deployment via Ingress

Answer

Recreate strategy

Question 3

Which of the following is a key principle of microservices architecture?

Accepted Answer

Loose coupling and independent deployability. Microservices architecture emphasizes breaking an application into small, independently deployable services that communicate over well-defined APIs. The correct answer is C: Loose coupling and independent deployability are key principles. Option A (shared database) contradicts the principle of service autonomy. Option B (tight coupling) is the opposite of what microservices aim for. Option D (monolithic codebase) is what microservices avoid.

Answer

Shared database schema for all services

Answer

Tight coupling between services

Answer

Building a large, monolithic codebase

Question 4

Which THREE of the following are valid ways to expose a Service to external traffic? (Select exactly three.)

Accepted Answer

Ingress. Ingress (A) is correct because an Ingress resource defines HTTP/HTTPS routing rules that expose Services externally through an Ingress controller acting as a layer-7 entry point. NodePort (D) is correct because it allocates a static port on every node's IP (default range 30000-32767), making the Service reachable from outside the cluster via :. LoadBalancer (E) is correct because it provisions an external load balancer (e.g., via a cloud provider) that distributes traffic to the Service from outside the cluster. ExternalName (B) is not a way to expose a Service; it merely maps a Service to an external DNS name via a CNAME record without proxying traffic. ClusterIP (C) is not externally accessible since it only assigns an internal virtual IP reachable within the cluster.

Answer

ExternalName

Answer

ClusterIP

Question 5

Which of the following are core components of the Flux GitOps toolkit?

Accepted Answer

Helm Controller. The Flux GitOps toolkit is built from a set of Kubernetes controllers, and the Helm Controller (A) is one of them: it reconciles HelmRelease custom resources to install, upgrade, and roll back Helm charts declaratively. The Source Controller (C) is also a core Flux component, providing GitRepository, HelmRepository, Bucket, and OCIRepository sources that other Flux controllers consume. The Kustomize Controller (E) is likewise core, reconciling Kustomization resources to build and apply manifests from those sources. Helm (B) is a package manager tool that Flux's Helm Controller uses, but it is not itself a Flux toolkit component, and the ArgoCD Application Controller (D) belongs to Argo CD, a competing GitOps tool, not Flux.

Answer

Helm

Answer

ArgoCD Application Controller

Question 6

Match each Kubernetes object to its typical use case.

Accepted Answer

Deployment: Manage stateless applications with rolling updates and rollbacks. Correct matches: Deployment manages stateless apps with rolling updates; StatefulSet handles stateful apps with stable identities; DaemonSet runs a pod on every node. Common confusions: mixing Deployment with DaemonSet (one per node vs. stateless management) and StatefulSet with Jobs (stateful vs. batch).

Answer

Deployment: Ensure one pod per node in the cluster

Answer

StatefulSet: Run a batch job to completion

Question 7

Which THREE of the following are components of the OpenTelemetry project?

Accepted Answer

Collector. The OpenTelemetry project is composed of several core deliverables, and the Collector (B) is one of them: it is a vendor-neutral agent/gateway that receives, processes, and exports telemetry (traces, metrics, logs) via receivers, processors, and exporters. The Specification (C) is also a core component, defining the cross-language API, SDK, protocol (OTLP), and semantic conventions that all implementations must follow. SDKs (E) are likewise a core component, providing language-specific implementations (e.g., Java, Go, Python, .NET) that generate and export telemetry according to the specification. Prometheus (A) is a separate CNCF monitoring system and time-series database, not a component of OpenTelemetry, though OTel can export metrics to it. Jaeger (D) is a separate distributed tracing backend (also CNCF) that predates and is independent of OpenTelemetry, even though it can receive OTLP data.

Answer

Prometheus

Answer

Jaeger

Question 8

What is the primary purpose of a Namespace in Kubernetes?

Accepted Answer

To isolate resources and provide a scope for names. Namespaces in Kubernetes provide a mechanism for isolating groups of resources within a single cluster. They create separate scopes for resource names, meaning that resource names (like Pods or Services) only need to be unique within a Namespace, not across the entire cluster. This allows multiple teams or projects to share a cluster without naming conflicts, and it also enables cluster administrators to apply policies (like ResourceQuotas) and network policies at the Namespace level.

Answer

To set resource quotas for the entire cluster

Answer

To define network policies for pods

Answer

To manage node affinity rules

Question 9

A company is adopting a multi-cloud strategy to avoid vendor lock-in. Which pattern BEST supports deploying applications across different cloud providers with minimal changes?

Accepted Answer

Deploy applications using Kubernetes on each cloud. Deploying applications using Kubernetes on each cloud provides a consistent orchestration and API layer across providers, so workloads can be moved with minimal changes. Kubernetes abstracts compute, networking, and storage through standard primitives (Pods, Services, PVCs), reducing provider-specific coupling. This is the core pattern for portable multi-cloud deployments.

Answer

Use a hybrid cloud approach with a single cloud for all workloads

Answer

Use each cloud provider's native services directly

Answer

Write application code that checks the cloud provider and adapts

Question 10

Which Kubernetes component is the primary entry point for all administrative tasks and exposes the REST API?

Accepted Answer

kube-apiserver. The kube-apiserver is the front-end of the Kubernetes control plane and the sole component that exposes the Kubernetes REST API. All administrative tasks—whether performed via kubectl, the Kubernetes dashboard, or direct API calls—must go through the API server, which validates and processes requests before storing state in etcd. Without the API server, no other component (scheduler, controller-manager, etc.) can interact with the cluster state.

Answer

kube-controller-manager

Answer

etcd

Answer

kube-scheduler

Question 11

Which two scenarios would benefit from using a StatefulSet instead of a Deployment? (Choose two.)

Accepted Answer

An application that requires persistent storage unique to each instance. Option A is correct because a StatefulSet provides each Pod with a stable, unique identity and its own PersistentVolumeClaim via volumeClaimTemplates, so each replica keeps dedicated persistent storage that survives rescheduling — something a Deployment cannot guarantee since its Pods share no ordinal-based PVC binding. Option B is correct because StatefulSet Pods get predictable, stable DNS names through a headless Service (e.g., pod-0.svc.namespace.svc.cluster.local), which database clusters such as MySQL, PostgreSQL, or etcd need for peer discovery and quorum. Option C is wrong because run-once batch workloads are better handled by a Job (or CronJob), not a StatefulSet or Deployment. Option D is wrong because stateless horizontally scalable web apps are the canonical use case for a Deployment, which offers rolling updates and replica management without per-Pod identity. Option E is wrong because node-agnostic microservices are stateless by nature and gain nothing from StatefulSet's stable identity or storage guarantees.

Answer

A batch job that runs once and exits

Answer

A stateless web application that can scale horizontally

Answer

A microservice that can use any available node

Question 12

Which component runs on each worker node and ensures that containers are running as specified in the Pod spec?

Accepted Answer

kubelet. The kubelet is the primary node agent that runs on every worker node in a Kubernetes cluster. It receives PodSpec definitions (via the API server or a file) and ensures that the containers described in those PodSpecs are running and healthy. It does this by interacting with the container runtime (e.g., containerd or CRI-O) to start, stop, and monitor containers, and it reports the node and pod status back to the control plane.

Answer

kube-proxy

Answer

kube-scheduler

Answer

kube-controller-manager

Question 13

An application is deployed across multiple cloud providers (AWS and GCP) to avoid vendor lock-in. This is an example of which pattern?

Accepted Answer

Multi-cloud. Multi-cloud refers to using services from multiple cloud providers simultaneously.

Answer

Public cloud

Answer

Federated cloud

Answer

Hybrid cloud

Question 14

In PromQL, which function would you use to calculate the per-second rate of increase of a counter over a specified time window?

Accepted Answer

rate(). The rate() function calculates the per-second average rate of increase of a counter over a time range.

Answer

delta()

Answer

avg_over_time()

Answer

increase()

Question 15

In a CI/CD pipeline, what is the difference between continuous delivery and continuous deployment?

Accepted Answer

Continuous delivery requires manual approval for production deployment; continuous deployment automates it. Continuous delivery automates the build, test, and staging deployment so that every change is release-ready, but the final push to production requires a manual approval or button click. Continuous deployment goes one step further and automatically releases every validated change to production without human intervention. The distinction is purely about whether production deployment is gated by a human.

Answer

Continuous delivery automatically deploys to production; continuous deployment does not

Answer

There is no difference; the terms are used interchangeably

Answer

Continuous deployment runs tests; continuous delivery does not