KCNA Kubernetes Fundamentals Practice Test 23 — 15 Questions

Question 1

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 2

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 3

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 PersistentVolumeClaim (PVC) stays in 'Pending' state until a suitable PersistentVolume (PV) is available to bind. Two common reasons are: (1) No existing PV matches the PVC's storage class and size requirements (static provisioning failure), and (2) The PVC references a StorageClass that does not exist, preventing dynamic provisioning. Other reasons like pod scheduling or dynamic provisioner unavailability are not among the two correct answers.

Answer

The pod that references the PVC is not scheduled yet

Answer

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

Answer

The cluster's dynamic provisioner is unavailable or misconfigured

Question 4

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 5

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

Accepted Answer

etcd. etcd is the distributed key-value store that serves as Kubernetes' single source of truth for cluster state, including all object definitions, configurations, and statuses. The control plane components (kube-apiserver, scheduler, controller-manager) are stateless and rely on etcd to persist and retrieve cluster data. Without etcd, the cluster cannot recover its state after a restart.

Answer

kube-scheduler

Answer

kube-apiserver

Answer

kube-controller-manager

Question 6

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 7

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 8

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. 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 9

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. 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 10

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 11

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

Accepted Answer

kubectl create deployment nginx --image=nginx:1.19. 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 12

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. 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 13

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

Accepted Answer

resources.requests.cpu. 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

Question 14

What is the role of the kubelet on a worker node?

Accepted Answer

It ensures containers are running in a Pod as specified. The kubelet is the primary node agent that runs on every worker node. Its core responsibility is to ensure that containers described in Pod specs (received from the API server via the kube-apiserver) 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 Pod and node status back to the control plane.

Answer

It stores cluster state

Answer

It manages network rules for Services

Answer

It runs the container runtime

Question 15

Which two of the following are valid ways to expose a Deployment externally to the internet? (Select TWO)

Accepted Answer

Create a Service of type LoadBalancer. A Service of type LoadBalancer provisions an external load balancer (e.g., in cloud environments like AWS, GCP, or Azure) that assigns a public IP or DNS name, making the Deployment directly accessible from the internet. This is a standard method for exposing services externally in Kubernetes.

Answer

Create a Service of type ClusterIP

Answer

Create an Ingress resource

Answer

Create a Headless Service