KCNA Kubernetes Fundamentals Practice Test 28 — 15 Questions

Question 1

Which of the following is the smallest deployable unit in Kubernetes?

Accepted Answer

Pod. The Pod is the smallest deployable unit in Kubernetes because it represents a single instance of a running process in the cluster and encapsulates one or more containers that share the same network namespace, storage volumes, and lifecycle. Containers are not directly scheduled onto Nodes; instead, Kubernetes always schedules and manages Pods, making the Pod the atomic unit of deployment.

Answer

Container

Answer

Node

Answer

Deployment

Question 2

A pod is stuck in 'Pending' state. Which of the following is a likely cause?

Accepted Answer

Insufficient CPU or memory resources on any available node. A pod remains in 'Pending' state when the scheduler cannot find a suitable node to run it. The most common reason is insufficient CPU or memory resources on any available node, as the scheduler checks resource requests against node allocatable resources before binding the pod. If no node meets the pod's resource requirements, the pod stays pending until resources become available.

Answer

The pod's command returned a non-zero exit code

Answer

The container image is invalid

Answer

The pod's liveness probe failed

Question 3

Which of the following kubectl commands would you use to update a Deployment's image to 'nginx:1.21' and record the change in the rollout history?

Accepted Answer

kubectl set image deployment/nginx nginx=nginx:1.21 --record. `kubectl set image deployment/nginx nginx=nginx:1.21 --record` updates the container image of the specified deployment and, with the `--record` flag, annotates the change in the rollout history (stored in the `kubernetes.io/change-cause` annotation). This allows you to later inspect the change with `kubectl rollout history deployment/nginx`.

Answer

kubectl edit deployment nginx --image=nginx:1.21

Answer

kubectl set image deployment/nginx nginx=nginx:1.21

Answer

kubectl patch deployment nginx -p '{"spec":{"template":{"spec":{"containers":[{"name":"nginx","image":"nginx:1.21"}]}}}}' --record

Question 4

What is the purpose of kube-proxy on a worker node?

Accepted Answer

To implement network rules and handle service traffic routing. Kube-proxy is the component responsible for implementing network rules on each worker node, enabling service abstraction by managing IP tables or IPVS rules to route traffic to the appropriate pods. It handles service discovery and load balancing for ClusterIP, NodePort, and LoadBalancer service types, ensuring that traffic destined for a service is correctly forwarded to healthy pod endpoints.

Answer

To run the container runtime

Answer

To store cluster configuration data

Answer

To monitor pod health and restart unhealthy containers

Question 5

Which of the following is used to logically isolate resources within a Kubernetes cluster?

Accepted Answer

Namespaces. Namespaces provide logical isolation for resources. Option C is correct.

Answer

Annotations

Answer

Selectors

Answer

Labels

Question 6

Which two of the following are responsibilities of the kubelet? (Select TWO.)

Accepted Answer

Reporting the node's status to the control plane. The kubelet is the primary node agent that registers the node with the Kubernetes control plane and periodically reports the node's status, including conditions like Ready, DiskPressure, and MemoryPressure, via the NodeStatus API. This heartbeat mechanism allows the control plane to maintain an accurate view of cluster health and node availability.

Answer

Implementing network rules for services

Answer

Assigning pods to nodes based on resource availability

Answer

Storing cluster state in a key-value store

Question 7

Which two of the following are true about ConfigMaps? (Select TWO.)

Accepted Answer

ConfigMaps are namespace-scoped. ConfigMaps are namespace-scoped objects (B) and can be mounted as volumes or exposed as environment variables (D).

Answer

ConfigMaps are automatically encrypted at rest

Answer

ConfigMaps can hold binary data

Answer

ConfigMaps are used to store sensitive configuration data

Question 8

What is the primary purpose of Kubernetes?

Accepted Answer

To orchestrate containers across a cluster. Kubernetes is a container orchestration platform designed to automate the deployment, scaling, and management of containerized applications across a cluster of nodes. Its primary purpose is to abstract the underlying infrastructure and provide a declarative way to run and manage containers, ensuring desired state and self-healing. This directly corresponds to orchestrating containers across a cluster, not compiling code, running VMs, or managing physical servers.

Answer

To compile source code

Answer

To run virtual machines

Answer

To manage physical servers

Question 9

Which TWO components are part of the Kubernetes control plane?

Accepted Answer

kube-apiserver. The Kubernetes control plane manages the cluster's state and scheduling decisions. The kube-apiserver (C) is the front-end for the control plane, exposing the Kubernetes API, while etcd (D) is the distributed key-value store that holds all cluster data, including configuration and state. Both are essential control plane components.

Answer

container runtime

Answer

kubelet

Answer

kube-proxy

Question 10

Which TWO of the following are true about Kubernetes Pods?

Accepted Answer

A Pod is the smallest deployable unit in Kubernetes. A Pod is the smallest and most basic deployable unit in Kubernetes. It represents a single instance of a running process and encapsulates one or more containers, storage resources, and a unique network IP. You cannot deploy a container directly; you must always wrap it in a Pod.

Answer

A Pod always runs exactly one container

Answer

Pods are automatically rescheduled if a node fails

Answer

Pods are directly created by the kube-scheduler

Question 11

Which THREE of the following are valid ways to create a Kubernetes resource using kubectl?

Accepted Answer

kubectl run nginx --image=nginx. `kubectl run nginx --image=nginx` creates a Pod imperatively, which is a valid way to create a Kubernetes resource directly from the command line without a manifest file. This command generates a Pod named 'nginx' using the specified container image, and it is a supported method for quick testing or ad-hoc resource creation.

Answer

kubectl exec -it pod-name -- /bin/bash

Answer

kubectl logs pod-name

Question 12

Which TWO statements about Kubernetes Services are correct?

Accepted Answer

A Service provides a stable IP address for Pods. A Kubernetes Service provides a stable virtual IP address that remains constant even as the underlying Pods are created, destroyed, or rescheduled. This decouples clients from the ephemeral nature of Pod IPs, ensuring reliable connectivity within the cluster.

Answer

A Service can only route traffic to Pods in the same namespace

Answer

A Service can only be of type ClusterIP

Answer

A Service automatically scales Pods based on load

Question 13

A pod is stuck in Pending state. Which THREE of the following are possible causes?

Accepted Answer

The pod specifies a nodeSelector that does not match any node. A pod enters a Pending state when it cannot be scheduled onto a node. A `nodeSelector` constraint requires the node to have specific labels; if no node matches, the scheduler cannot place the pod, leaving it Pending. This is a common scheduling failure cause.

Answer

The container image does not exist

Answer

The pod has a liveness probe that is failing

Question 14

Which TWO resources can be used to store configuration data separately from container images?

Accepted Answer

Secret. ConfigMaps and Secrets are Kubernetes API objects designed specifically to decouple configuration data and sensitive information from container images. ConfigMaps store non-sensitive key-value pairs (e.g., environment variables, command-line arguments, or configuration files), while Secrets store sensitive data (e.g., passwords, tokens, or SSH keys) in base64-encoded or encrypted form. Both can be mounted into pods as volumes or injected as environment variables, allowing image reuse across different environments without rebuilding.

Answer

Service

Answer

PersistentVolume

Answer

Deployment

Question 15

Which THREE fields are required in a Kubernetes manifest YAML file?

Accepted Answer

kind. The 'kind' field is required because it tells Kubernetes which type of object to create (e.g., Pod, Deployment, Service). Without it, the API server cannot route the manifest to the correct resource handler. It must be a valid Kubernetes resource kind from the core API or a custom resource definition.

Answer

status

Answer

spec