KCNA Kubernetes Fundamentals Practice Test 22 — 15 Questions

Question 1

A developer deploys a CronJob that runs a batch job every 5 minutes. After a while, they notice that the job fails with 'DeadlineExceeded' and the pod is stuck in 'PodInitializing' state. What is the most likely reason?

Accepted Answer

A pre-existing InitContainer is failing or stuck. The 'PodInitializing' state indicates that the pod is stuck before its main containers can start, which is typically caused by an InitContainer that is failing or hanging. Since the job fails with 'DeadlineExceeded', the pod's activeDeadlineSeconds (or the CronJob's startingDeadlineSeconds) has been reached while the InitContainer is still running, preventing the main container from executing. This is the most likely reason because InitContainers run sequentially to completion before any main containers start, and a stuck InitContainer blocks the entire pod lifecycle.

Answer

The CronJob schedule is misconfigured

Answer

The container runtime is not installed on the node

Answer

The job's backoffLimit is set too low

Question 2

Which TWO of the following are functions of the kube-controller-manager?

Accepted Answer

Running the node controller to monitor node health. The kube-controller-manager is a core control plane component that runs controller processes, including the node controller, which monitors node health by checking the NodeStatus and NodeLease objects. If a node becomes unreachable (e.g., the node controller fails to receive a heartbeat within the --node-monitor-grace-period, default 40 seconds), it marks the node as Unhealthy and eventually taints it to trigger pod eviction. This makes option D correct because the node controller is a built-in controller within the kube-controller-manager.

Answer

Serving the Kubernetes API

Answer

Implementing network rules for Services

Answer

Scheduling pods to nodes

Question 3

Which THREE of the following are valid ways to expose a set of pods as a network service in Kubernetes?

Accepted Answer

ClusterIP. A ClusterIP service exposes the set of pods on a cluster-internal IP address, making it reachable only from within the cluster. This is the default service type in Kubernetes and is valid for internal communication between workloads. It does not provide external access, but it is a core method for exposing pods as a network service.

Answer

Ingress

Answer

ExternalName

Question 4

Which TWO of the following are valid reasons that a PersistentVolumeClaim (PVC) may remain in 'Pending' state?

Accepted Answer

No PersistentVolume exists that matches the PVC's storage class and size requirements. A PVC stays Pending if no matching PV exists that satisfies its requirements (storage class, access mode, size) or if there are insufficient resources on available nodes to bind the PV. The PV must be manually bound or dynamically provisioned.

Answer

The pod that references the PVC is not scheduled yet

Answer

The PVC is using a StorageClass that does not exist

Answer

The PVC's access mode is 'ReadWriteMany' but the underlying storage only supports 'ReadWriteOnce'

Question 5

What is the primary purpose of a Kubernetes Service?

Accepted Answer

To provide a stable network endpoint for a set of Pods. A Service provides a stable endpoint for a set of Pods, enabling discovery and load balancing across them.

Answer

To manage rolling updates of Pods

Answer

To schedule Pods onto Nodes

Answer

To store configuration data for Pods

Question 6

Which component of the Kubernetes control plane is responsible for storing the cluster state?

Accepted Answer

etcd. etcd is a distributed key-value store that holds all cluster data, including configuration, state, and metadata.

Answer

kube-scheduler

Answer

kube-apiserver

Answer

kube-controller-manager

Question 7

You have a Deployment defined with replicas: 5. You run 'kubectl scale deployment myapp --replicas=3'. Which component is responsible for ensuring the actual number of Pods matches the desired 3?

Accepted Answer

Deployment controller in kube-controller-manager. The Deployment controller, which runs as part of the kube-controller-manager, is responsible for reconciling the desired state of a Deployment. When you run 'kubectl scale deployment myapp --replicas=3', the Deployment controller detects the change in the Deployment's replica count and creates or deletes Pods via the ReplicaSet controller to match the desired 3 replicas.

Answer

etcd

Answer

kubelet

Answer

kube-scheduler

Question 8

Which Kubernetes object should you use to store non-sensitive configuration data that can be consumed by Pods as environment variables or mounted files?

Accepted Answer

ConfigMap. ConfigMap is the correct Kubernetes object for storing non-sensitive configuration data, such as key-value pairs or configuration files. It is designed to decouple configuration artifacts from container images, allowing Pods to consume this data as environment variables, command-line arguments, or mounted files in a volume. Unlike Secrets, ConfigMaps do not provide encryption or base64 encoding by default, making them suitable only for non-sensitive information.

Answer

Secret

Answer

PersistentVolume

Answer

Service

Question 9

A Pod is in the 'Pending' state. What is the most likely cause?

Accepted Answer

The Pod is still being scheduled because no Node has enough resources. Pending typically means the Pod has been accepted but not yet scheduled, often due to insufficient resources or node availability.

Answer

The container image is missing

Answer

The Service referencing the Pod does not exist

Answer

The application inside the container has crashed

Question 10

Which kubectl command would you use to view the logs of a specific container named 'app' in a multi-container Pod named 'web-pod'?

Accepted Answer

kubectl logs web-pod -c app. Option C is correct because the `kubectl logs` command uses the `-c` flag to specify a container name within a multi-container Pod. The correct syntax is `kubectl logs -c `, which targets the 'app' container inside 'web-pod'.

Answer

kubectl log web-pod container app

Answer

kubectl logs web-pod app

Answer

kubectl logs app web-pod

Question 11

A Deployment is rolling out a new version. The rollout has stalled, and 'kubectl rollout status deployment/myapp' shows 'Waiting for deployment rollout to finish: 2 out of 5 new replicas have been updated...'. The Deployment's spec.strategy.rollingUpdate.maxUnavailable is set to 25% and maxSurge is 25%. What is the maximum number of Pods that could be unavailable during this rollout?

Accepted Answer

2. Option C is correct because with maxUnavailable=25% and maxSurge=25%, the maximum number of unavailable Pods during a rolling update is calculated as the ceiling of 25% of the desired replicas (5), which is 2. This means up to 2 Pods can be unavailable at any time, ensuring the rollout can proceed while maintaining availability.

Answer

1

Answer

3

Answer

0

Question 12

You need to run a batch job that processes a queue and then terminates. Which Kubernetes resource is most appropriate?

Accepted Answer

Job. A Job is the correct resource because it is designed to run a specified number of pods to completion and then terminate, making it ideal for batch processing tasks like processing a queue. Unlike controllers that maintain a desired state indefinitely, a Job ensures the pod runs successfully to completion, even if the pod fails and needs to be restarted, and then stops.

Answer

StatefulSet

Answer

Deployment

Answer

DaemonSet

Question 13

Which command creates a Deployment named 'nginx' from the 'nginx:1.19' image?

Accepted Answer

kubectl create deployment nginx --image=nginx:1.19. Option B is correct because the `kubectl create deployment` command is the standard Kubernetes imperative method to create a Deployment resource, and specifying `--image=nginx:1.19` directly sets the container image for the pod template. This command generates a Deployment object that manages a ReplicaSet with the specified image, ensuring declarative updates and rollback capabilities.

Answer

kubectl run nginx --image=nginx:1.19

Answer

kubectl start deployment nginx --image=nginx:1.19

Answer

kubectl apply -f nginx-deployment.yaml

Question 14

A developer reports that a Pod cannot reach another Service in the same namespace via its DNS name. The Service name is 'api'. What is the correct DNS query for a Pod to resolve this Service?

Accepted Answer

api. Option C is correct because when a Pod and a Service are in the same namespace, Kubernetes DNS resolves the Service using just the Service name (e.g., 'api'). The DNS search domain configured in the Pod's resolv.conf (e.g., <namespace>.svc.cluster.local) appends the namespace and cluster suffix automatically, so a short query like 'api' resolves correctly without needing the full FQDN.

Answer

api.svc.cluster.local

Answer

api.namespace.svc.cluster.local

Answer

api.default.svc.cluster.local

Question 15

Which field in a Pod's container specification defines the minimum amount of CPU guaranteed to the container?

Accepted Answer

resources.requests.cpu. Option B is correct because in Kubernetes, the `resources.requests.cpu` field specifies the minimum amount of CPU guaranteed to a container. This value is used by the scheduler to ensure the node has enough allocatable CPU, and by the kubelet to enforce CPU shares via the Completely Fair Scheduler (CFS) in the Linux kernel.

Answer

spec.containers.cpu

Answer

resources.limits.cpu

Answer

spec.nodeSelector