KCNA Practice Test 50 — 15 Questions

Question 1

You want to ensure that a Pod runs on every Node in the cluster. Which resource should you use?

Accepted Answer

DaemonSet. A DaemonSet ensures that a copy of a Pod runs on every Node in the cluster, including when new Nodes are added. This is the correct resource for cluster-wide services like log collectors, monitoring agents, or kube-proxy, as it automatically schedules a Pod on each Node and respects node taints and tolerations.

Answer

Deployment

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ReplicaSet

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StatefulSet

Question 2

Which two of the following are benefits of using Kubernetes for container orchestration? (Select TWO.)

Accepted Answer

Self-healing: automatically restarts failed containers. Option C is correct because Kubernetes provides self-healing through controllers such as ReplicaSets and Deployments: when a container or Pod fails, the kubelet and control-plane reconciliation loop detect the deviation from the desired state and automatically restart or replace the failed container to maintain the declared replica count. Option E is correct because Kubernetes supports automated rollouts and rollbacks via Deployment objects, where changes to the Pod template trigger a rolling update (using maxSurge/maxUnavailable) and `kubectl rollout undo` reverts to a previous ReplicaSet revision. The unmarked options do not belong: A is incorrect because Kubernetes is an orchestration platform, not a CI system (CI is handled by tools like Jenkins, GitLab CI, or Tekton), B is incorrect because Kubernetes does not compile source code—it runs pre-built container images, and D is incorrect because Kubernetes does not provide built-in database management; stateful databases require operators or external services.

Answer

Integrated continuous integration pipeline

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Automatic code compilation

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Built-in database management

Question 3

An organization wants to implement a serverless function that scales to zero when not in use. Which technology is specifically designed to achieve this on Kubernetes?

Accepted Answer

Knative. Knative is a Kubernetes-based platform specifically designed to run serverless workloads, and its Serving component includes scale-to-zero as a core feature — pods are removed when there is no traffic and recreated on demand. It builds on Kubernetes primitives but adds the autoscaling and request-driven activation needed for true serverless behavior. This makes it the purpose-built answer for scale-to-zero functions on Kubernetes.

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Prometheus

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Istio

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Kubernetes Horizontal Pod Autoscaler (HPA)

Question 4

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?

Accepted Answer

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

The Source Controller directly applies the manifest to the cluster

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Flux uses HelmReleases to apply changes

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Flux requires a manual kubectl apply to sync

Question 5

Which TWO of the following are examples of context propagation mechanisms used in distributed tracing?

Accepted Answer

HTTP headers. HTTP headers, such as the `traceparent` and `tracestate` headers defined in the W3C Trace Context specification, are the standard mechanism for propagating trace context across service boundaries in distributed tracing. When a service receives an incoming HTTP request, it extracts the trace ID and span ID from these headers to continue the same trace. This allows trace data to be correlated across multiple microservices as the request flows through the system.

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Environment variables

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Database queries

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Shared filesystem

Question 6

A developer wants to view the logs of a specific container named 'sidecar' inside a pod named 'app-pod'. Which command should they use?

Accepted Answer

kubectl logs app-pod -c sidecar. The -c flag specifies the container name. The correct command is 'kubectl logs app-pod -c sidecar'.

Answer

kubectl log app-pod --container sidecar

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kubectl logs app-pod sidecar

Answer

kubectl logs -c sidecar app-pod

Question 7

Which two of the following are characteristics of container images built using OCI standards? (Choose two.)

Accepted Answer

They are portable across different container runtimes. Option A is correct because OCI (Open Container Initiative) image specifications define a runtime-agnostic format, so an image built to OCI standards can be pulled and executed by any OCI-compliant runtime such as containerd, CRI-O, or Docker, not just one vendor's engine. Option B is correct because OCI images are built as a stack of content-addressable layers, each identified by a digest, which allows runtimes and registries to cache and reuse unchanged layers across builds and pulls, reducing storage and transfer overhead. Option C is incorrect because containers share the host kernel and do not bundle a full guest operating system; that characteristic belongs to virtual machines. Option D is incorrect because OCI compliance explicitly enables portability beyond Docker to other runtimes like containerd and CRI-O. Option E is incorrect because containers run directly on the host kernel via namespaces and cgroups, requiring no hypervisor (except in specialized VM-isolated setups, which are not the norm for OCI images).

Answer

They include a full guest operating system

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They can only be run by Docker

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They require a hypervisor to run

Question 8

A development team wants to adopt a cloud-native architecture for a new application. Which set of principles BEST describes the cloud-native approach?

Accepted Answer

Microservices, containers, dynamic orchestration, and DevOps. Cloud-native is defined by the CNCF as combining containers, microservices, service meshes, immutable infrastructure, and declarative APIs — with dynamic orchestration (Kubernetes) and DevOps culture as the operational backbone. Option A bundles all four pillars correctly: microservices for decomposition, containers for packaging, dynamic orchestration for scheduling/scaling, and DevOps for the cultural/process model. These four elements reinforce each other: containers enable microservices, orchestration makes containers manageable at scale, and DevOps provides the feedback loops.

Answer

Service-oriented architecture, bare-metal servers, static scaling, and Agile

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Monolithic applications, virtual machines, manual scaling, and waterfall development

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Serverless functions, virtual machines, manual provisioning, and ITIL

Question 9

An administrator needs to expose a set of pods running a web application on a static port on each node's IP address. Which Service type should they use?

Accepted Answer

NodePort. A NodePort service exposes the application on a static port (30000–32767) on every node's IP address, making the pods accessible externally via :. This matches the requirement to expose pods on a static port on each node's IP address without needing an external load balancer.

Answer

ClusterIP

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ExternalName

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LoadBalancer

Question 10

What is the primary purpose of the sidecar container in a service mesh?

Accepted Answer

To intercept and manage network traffic for the main container. In a service mesh, the sidecar container (typically an Envoy or Linkerd proxy) is injected alongside the main application container to intercept and manage all inbound and outbound network traffic. This allows the service mesh to enforce traffic policies, handle service discovery, implement retries and circuit breaking, and collect telemetry without modifying the application code. The sidecar operates at the network layer (L4/L7), decoupling communication concerns from business logic.

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To run application business logic

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To handle logging and monitoring of the main container

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To provide persistent storage for the main container

Question 11

A team wants to deploy a batch job that runs once to process a large dataset. The job should run to completion and then terminate. Which Kubernetes resource should be used?

Accepted Answer

Job. A Job resource is designed for batch processing tasks that run to completion and then terminate. It creates one or more Pods and ensures they successfully finish their work, making it the correct choice for a one-time data processing job.

Answer

DaemonSet

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CronJob

Answer

Deployment

Question 12

A development team deploys a microservice that crashes every few minutes. The deployment uses a single replica, and the pod restarts repeatedly. Which Kubernetes feature should be enabled to ensure the service remains available during failures?

Accepted Answer

Increase the replicas in the Deployment to at least 2. Increasing the replicas to at least 2 ensures that if one pod crashes, the other replica(s) can continue serving traffic, maintaining availability. With only a single replica, the service becomes unavailable every time the pod restarts. This is the most direct way to provide redundancy and fault tolerance for a stateless microservice.

Answer

Move the deployment to a separate namespace

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Store the application configuration in a ConfigMap

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Add a readiness probe to the pod

Question 13

Which THREE of the following are characteristics of a microservices architecture? (Select 3)

Accepted Answer

Loose coupling between services. Microservices architecture emphasizes loose coupling, where each service communicates via well-defined APIs (e.g., REST, gRPC) and does not share internal implementation details. This allows services to evolve independently without affecting others, which is a core principle of the architecture.

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Services share the same database schema

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All services are packaged in a single monolithic deployment

Question 14

Which GitOps tool is specifically designed for Kubernetes and follows the declarative GitOps pattern, continuously reconciling the desired state from a Git repository?

Accepted Answer

ArgoCD. ArgoCD is a declarative GitOps continuous delivery tool for Kubernetes that syncs application state with a Git repository.

Answer

Helm

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Terraform

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Jenkins

Question 15

An organization uses GitOps with ArgoCD to manage Kubernetes deployments. What is the PRIMARY advantage of this approach over traditional imperative deployment methods?

Accepted Answer

It provides a single source of truth for cluster state through Git. GitOps uses a Git repository as the single source of truth, enabling declarative configuration, version control, and automated reconciliation. This is the primary advantage over traditional imperative methods. Option A is incorrect because manual approval processes can still be part of a GitOps workflow. Option C is incorrect because GitOps does not eliminate the need for access controls. Option D is incorrect because GitOps does not directly reduce container count.

Answer

It eliminates the need for any manual approval processes

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It allows developers to directly access the Kubernetes cluster

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It reduces the number of containers needed in a deployment