KCNA Kubernetes Fundamentals Practice Test 7 — 15 Questions

Question 1

What is the primary purpose of the Kubernetes control plane component 'kube-apiserver'?

Accepted Answer

Expose the Kubernetes REST API and act as the entry point for all administrative tasks. The kube-apiserver is the front-end of the Kubernetes control plane, exposing the Kubernetes REST API. It validates and processes all administrative requests (e.g., creating pods, scaling deployments) and is the only component that directly interacts with the etcd datastore. This makes it the central entry point for all cluster management tasks, aligning with option D. Other options are incorrect: A describes the kubelet, B describes the kube-scheduler, and C describes etcd.

Answer

Run container runtime operations on nodes

Answer

Schedule pods onto nodes

Answer

Store cluster state and configuration

Question 2

Your application requires persistent storage that must be available across pod restarts and rescheduling. What is the recommended approach?

Accepted Answer

Use a PersistentVolumeClaim (PVC) and mount it into the pod. PersistentVolumeClaim (PVC) is the recommended approach because it decouples storage provisioning from pod lifecycle, ensuring data persists across pod restarts and rescheduling. PVCs request storage from a PersistentVolume (PV) that is backed by a physical storage system (e.g., NFS, cloud block storage), and the pod mounts this volume, allowing the data to survive even if the pod is deleted and recreated on a different node.

Answer

Store data in the container's writable layer

Answer

Use hostPath volume

Answer

Use an emptyDir volume

Question 3

A service of type ClusterIP is created but pods cannot reach it using the service name. The pods are in the same namespace. What is a likely cause?

Accepted Answer

CoreDNS is not running or misconfigured. When a ClusterIP service cannot be reached by its DNS name from pods in the same namespace, the most common cause is that CoreDNS (the cluster DNS resolver) is not running or is misconfigured. Kubernetes relies on CoreDNS to resolve service names to ClusterIP addresses; if CoreDNS is down or its configuration is incorrect, DNS queries for the service name will fail, even though the service itself and its endpoints are healthy.

Answer

The service is not exposed externally

Answer

The service port does not match the container port

Answer

The selector does not match any pod labels

Question 4

Which THREE of the following are valid apiVersions for Kubernetes resources?

Accepted Answer

batch/v1. (batch/v1) is correct because it is the stable API version for batch workloads like Jobs and CronJobs, which have been promoted to v1 after graduating from beta. Option B (v1) is correct as it is the core API group's stable version, used for fundamental resources like Pods, Services, and ConfigMaps. Option C (apps/v1) is correct because it is the stable API version for workload resources such as Deployments, StatefulSets, and DaemonSets, replacing the older apps/v1beta1 and apps/v1beta2 versions.

Answer

extensions/v1beta1

Answer

v1beta1

Question 5

Which kubectl command can be used to view detailed information about a specific pod, including its current state, events, and resource usage?

Accepted Answer

kubectl describe pod . The `kubectl describe pod ` command retrieves a detailed summary of the pod, including its current status (e.g., Running, Pending), lifecycle events (e.g., container restarts, scheduling decisions), and resource usage (e.g., CPU/memory requests and limits). It aggregates this information from the Kubernetes API server, providing a human-readable view of the pod's state and recent events, which is essential for debugging.

Answer

kubectl logs <pod-name>

Answer

kubectl exec <pod-name> -- /bin/sh

Answer

kubectl get pod <pod-name> -o yaml

Question 6

Two pods, 'app-v1' and 'app-v2', both have a label 'app: myapp'. A Service 'my-service' has a selector 'app: myapp'. How many endpoints will the Service initially have?

Accepted Answer

2. The Service's selector 'app: myapp' matches both pods 'app-v1' and 'app-v2', which both carry the label 'app: myapp'. The Service controller automatically creates endpoints for all pods matching the selector, regardless of their readiness state, unless a headless service or custom endpoint logic is involved. Initially, both pods are considered ready by default (unless a readiness probe fails), so the Service will have two endpoints.

Answer

1

Answer

0

Answer

Depends on pod readiness

Question 7

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. A Pod in 'Pending' state means the Pod has been accepted by the API server but is not yet running. The most common reason is that the scheduler cannot find a Node with sufficient CPU, memory, or other resources to place the Pod. This triggers the scheduler to continuously attempt to bind the Pod to a suitable Node, leaving it in Pending until resources become available or the Pod is deleted.

Answer

The container image is missing

Answer

The Service referencing the Pod does not exist

Answer

The application inside the container has crashed

Question 8

Which two statements about Pods are true? (Select TWO)

Accepted Answer

Containers in the same Pod share the same network namespace. Containers within the same Pod share the same network namespace, including IP address and port space. This allows them to communicate via localhost and is a fundamental design principle of Pods in Kubernetes, enabling sidecar patterns and efficient inter-process communication.

Answer

A Pod can only contain one container

Answer

A Pod is automatically recreated if its Node fails

Answer

Pods are always created directly by users

Question 9

A Deployment named 'web' has 3 replicas. You run 'kubectl scale deployment web --replicas=5'. What will happen?

Accepted Answer

Two additional Pods are created to reach a total of 5 replicas.. The `kubectl scale` command adjusts the replica count of a Deployment to the desired number. Since the Deployment currently has 3 replicas and the command sets `--replicas=5`, the ReplicaSet controller creates 2 additional Pods to match the desired state. No existing Pods are deleted or restarted unless the Pod template changes.

Answer

An error occurs because scaling a Deployment is not allowed.

Answer

The Deployment is updated and all Pods are restarted.

Answer

The existing Pods are deleted and 5 new Pods are created.

Question 10

Which THREE actions can be performed using kubectl without installing additional plugins?

Accepted Answer

Run 'kubectl edit deployment' to modify a Deployment in-place.. Options B, D, and E are built-in kubectl commands that work without any additional plugins. 'kubectl edit deployment' allows in-place editing of a Deployment by opening the manifest in an editor. 'kubectl cp' copies files between a local filesystem and a container. 'kubectl logs' retrieves logs from a container in a Pod. In contrast, 'kubectl debug' (A) is not a standard built-in command; it was introduced as an alpha feature and may require the EphemeralContainers feature gate. 'kubectl auth reconcile' (C) is a kubectl plugin, not a native command.

Answer

Run 'kubectl debug' to create a debugging Pod.

Answer

Run 'kubectl auth reconcile' to reconcile RBAC permissions.

Question 11

Which of the following is NOT a responsibility of the kubelet on a worker node?

Accepted Answer

Assign Pods to nodes based on resource requirements. Assigning Pods to nodes is the responsibility of the kube-scheduler, not the kubelet. The kubelet only runs on worker nodes and executes tasks related to managing the lifecycle of Pods assigned to that specific node by the scheduler.

Answer

Ensure containers are running as defined in the PodSpec

Answer

Report node and pod status to the API server

Answer

Execute liveness and readiness probes

Question 12

Which kubectl command would you use to view the logs of a container named 'web' inside a Pod named 'app-12345'?

Accepted Answer

kubectl logs app-12345 -c web. `kubectl logs app-12345 -c web` explicitly specifies the container name 'web' within the Pod 'app-12345' using the `-c` flag. Option C is also correct because `--container=web` is the long-form equivalent of `-c`, and it is a standard syntax accepted by kubectl. Options B and D are incorrect due to wrong order and flag usage.

Answer

kubectl logs -p web app-12345

Answer

kubectl logs web app-12345

Question 13

You apply the following YAML:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-deploy
spec:
  replicas: 3
  selector:
    matchLabels:
      app: web
  template:
    metadata:
      labels:
        app: web
    spec:
      containers:
      - name: nginx
        image: nginx:1.21

But the Deployment never creates any Pods. Which field is missing or incorrect?

Accepted Answer

The field 'spec.selector' is missing, which is required for Deployment. The provided YAML is valid. The 'spec.selector' field is present and correctly matches the template labels. The 'replicas' is set to 3, not 0. 'containers' is spelled correctly, and 'apiVersion: apps/v1' is correct for Deployment. Therefore, none of the listed options describe a real issue, and the Deployment should create Pods as expected.

Answer

The 'replicas' field is set to 0

Answer

The 'containers' field is misspelled as 'container'

Answer

The 'apiVersion' should be 'v1'

Question 14

Which Kubernetes primitive is the smallest and simplest unit in the Kubernetes object model that you can create or deploy?

Accepted Answer

Pod. B is correct because a Pod is the smallest and simplest unit in the Kubernetes object model. It represents a single instance of a running process in a cluster and can contain one or more containers that share the same network namespace, storage volumes, and lifecycle. You create and deploy Pods directly, while higher-level controllers like ReplicaSets and Deployments manage Pods as their fundamental building block.

Answer

ReplicaSet

Answer

Deployment

Answer

Container

Question 15

Which TWO of the following are responsibilities of the kubelet? (Select 2)

Accepted Answer

Registering the node with the cluster and reporting node status. The kubelet is the primary node agent that registers the node with the Kubernetes API server upon startup and continuously reports the node's status (e.g., conditions, capacity) via heartbeats (NodeStatus updates). This registration and status reporting are fundamental to the cluster's ability to manage and schedule workloads on that node.

Answer

Scheduling pods onto nodes based on resource availability

Answer

Creating and managing network iptables rules for Services

Answer

Storing cluster configuration data