KCNA Practice Test 26 — 15 Questions

Question 1

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

Answer

ExternalName

Answer

LoadBalancer

Question 2

A company is deploying a microservices application on Kubernetes. They want to ensure that configuration data, such as database URLs and feature flags, can be updated without rebuilding container images. Which Kubernetes resource should they use?

Accepted Answer

ConfigMaps. ConfigMaps are the correct Kubernetes resource for decoupling configuration data (like database URLs and feature flags) from container images. They allow you to inject configuration as environment variables or mounted volumes without rebuilding or redeploying the container image, enabling runtime updates.

Answer

Secrets

Answer

Services

Answer

Deployments

Question 3

Which tool is specifically designed for log aggregation and is built by Grafana Labs as a lightweight, cost-effective alternative to traditional log systems?

Accepted Answer

Loki. Loki is a log aggregation system optimized for Kubernetes, designed to be cost-effective and easy to operate.

Answer

Zipkin

Answer

Prometheus

Answer

Jaeger

Question 4

You create a Pod with the following YAML. What will happen when you apply it?

Accepted Answer

The Pod will be created with memory limit of 128Mi and CPU limit of 500m. The YAML defines resource limits and requests using standard Kubernetes units: '128Mi' for memory (mebibytes) and '500m' for CPU (millicores). These are valid and will be applied to the container, creating the Pod with the specified limits.

Answer

The Pod will fail to create because memory and CPU are in the wrong unit

Answer

The Pod will be created without resource limits because the syntax is incorrect

Answer

The Pod will be created but requests and limits will be ignored because they are not valid for Pods

Question 5

A user wants to ensure that a Deployment undergoes a rolling update with zero downtime, and that new Pods are fully ready before old Pods are terminated. Which field in the Deployment spec controls this behavior?

Accepted Answer

spec.strategy.rollingUpdate.maxUnavailable and maxSurge. `spec.strategy.rollingUpdate.maxUnavailable` and `maxSurge` control how many Pods can be unavailable and how many can be created above the desired count during a rolling update. Setting `maxUnavailable=0` ensures no old Pods are terminated until new Pods are fully ready, achieving zero-downtime updates. `maxSurge` allows extra Pods to be created before old ones are removed, enabling a controlled rollout.

Answer

spec.minReadySeconds

Answer

spec.replicas

Answer

spec.template.spec.containers[].resources

Question 6

Which of the following is a graduated CNCF project?

Accepted Answer

Prometheus. Prometheus is a graduated CNCF project, having reached the graduation maturity level in August 2018. It is a core monitoring and alerting toolkit widely adopted in cloud-native environments, and its graduation status reflects its stability, widespread use, and strong governance within the CNCF ecosystem.

Answer

OpenTelemetry

Answer

K3s

Answer

KubeEdge

Question 7

An administrator wants to perform a rolling update of a Deployment. Which TWO actions will achieve this?

Accepted Answer

Run 'kubectl set image deployment/myapp myapp=myapp:v2'. 'kubectl set image deployment/myapp myapp=myapp:v2' directly updates the container image in the Deployment's pod template, which triggers a rolling update by default. The Deployment controller then creates a new ReplicaSet with the updated image and gradually scales it up while scaling down the old ReplicaSet, ensuring zero downtime.

Answer

Run 'kubectl scale deployment myapp --replicas=0' then 'kubectl scale deployment myapp --replicas=5'

Answer

Run 'kubectl delete deployment' and then 'kubectl create deployment' with the new image

Answer

Run 'kubectl rollout undo deployment/myapp'

Question 8

Which component is responsible for managing the lifecycle of containers on a Kubernetes node?

Accepted Answer

kubelet. The kubelet is the primary node agent that runs on each Kubernetes node. It is responsible for ensuring that containers are running in a Pod as expected by interacting with the container runtime (e.g., Docker, containerd) to manage the container lifecycle—starting, stopping, and monitoring containers based on PodSpecs received from the API server.

Answer

kube-scheduler

Answer

kube-controller-manager

Answer

kube-apiserver

Question 9

Match each Kubernetes scheduler concept to its description.

Accepted Answer

NodeAffinity: Constraints on which nodes a pod can be scheduled based on node labels.. NodeAffinity and NodeSelector both use node labels but differ in expressiveness. PodAffinity schedules relative to other pods. Taints/Tolerations control which pods can be placed on nodes. Common confusion: swapping NodeAffinity with PodAffinity or Taints/Tolerations.

Answer

NodeAffinity: Ensures pods are scheduled together with other pods on the same node.

Answer

PodAffinity: Repels pods from nodes unless they have a specific label.

Question 10

Drag and drop the steps for a rolling update of a Kubernetes Deployment into the correct order.

Accepted Answer

1. Change the image, 2. Apply the change, 3. Monitor the rollout, 4. Verify the health, 5. Rollback if issues. Change the image, apply, monitor rollout, verify health, and rollback if issues arise.

Answer

1. Change the image, 2. Monitor the rollout, 3. Apply the change, 4. Verify the health, 5. Rollback if issues

Answer

1. Apply the change, 2. Change the image, 3. Monitor the rollout, 4. Verify the health, 5. Rollback if issues

Answer

1. Change the image, 2. Apply the change, 3. Verify the health, 4. Monitor the rollout, 5. Rollback if issues

Question 11

Match each Kubernetes networking concept to its description.

Accepted Answer

ClusterIP: Exposes the Service on a cluster-internal IP. Only reachable from within the cluster.. Common confusions arise between ClusterIP (internal-only) and NodePort (node-level external access), and between LoadBalancer (cloud-integrated external LB) and Ingress (HTTP routing with rules).

Answer

ClusterIP: Exposes the Service on each Node's IP at a static port.

Answer

NodePort: Exposes the Service on a cluster-internal IP.

Question 12

Which Kubernetes object provides a stable IP address and DNS name for a set of Pods?

Accepted Answer

Service. A Service provides a stable virtual IP address and a DNS name (e.g., my-svc.namespace.svc.cluster.local) that remains constant even as Pods are created or destroyed. This enables reliable network access to a dynamic set of Pods selected via labels, abstracting away Pod IP volatility.

Answer

Ingress

Answer

ConfigMap

Answer

Deployment

Question 13

Which TWO of the following are benefits of using a container orchestration platform like Kubernetes? (Select 2)

Accepted Answer

Automated scaling based on demand. Kubernetes includes a Horizontal Pod Autoscaler (HPA) that automatically adjusts the number of pod replicas based on observed CPU, memory, or custom metrics. This enables applications to scale out during traffic spikes and scale in during low demand, improving resource utilization and responsiveness without manual intervention.

Answer

Single-node deployment for simplicity

Answer

Manual scaling of applications

Answer

Elimination of all application bugs

Question 14

A developer needs to deploy a stateless application with three replicas and ensure that updates are rolled out with zero downtime. Which Kubernetes resource is most appropriate?

Accepted Answer

Deployment. A Deployment is the correct resource because it manages a ReplicaSet to ensure the desired number of pod replicas (three) are running, and it supports rolling updates with configurable strategies (e.g., maxSurge and maxUnavailable) to achieve zero-downtime updates. Stateless applications are ideal for Deployments since pods are interchangeable and can be replaced without data loss.

Answer

StatefulSet

Answer

Job

Answer

DaemonSet

Question 15

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.

Answer

Environment variables

Answer

Database queries

Answer

Shared filesystem