KCNA Kubernetes Fundamentals Practice Test 12 — 15 Questions

Question 1

Which THREE of the following are valid Kubernetes resource types?

Accepted Answer

Deployment. Deployment is a core Kubernetes resource that manages the lifecycle of Pods and ReplicaSets, providing declarative updates, scaling, and rollback capabilities. It is one of the most commonly used workload resources in Kubernetes, making option B correct.

Answer

DockerImage

Answer

VirtualMachine

Question 2

Which TWO statements about Namespaces are correct?

Accepted Answer

Resource names must be unique within a namespace. Kubernetes enforces that resource names must be unique within a namespace. This is a fundamental constraint: within a given namespace, you cannot have two resources of the same type (e.g., two Pods) with the same name. This uniqueness allows the API server to resolve resource references unambiguously when using namespaced resources.

Answer

Namespaces provide network isolation by default

Answer

All Kubernetes resources are namespaced

Answer

You can delete a namespace without affecting the resources inside it

Question 3

Which Kubernetes object provides stable network endpoints and load balancing for a set of pods?

Accepted Answer

Service. A Kubernetes Service provides a stable virtual IP (ClusterIP) and DNS name that remains constant even as Pods are created or destroyed. It uses label selectors to identify target Pods and performs TCP/UDP load balancing across them, ensuring reliable network access without requiring clients to track ephemeral Pod IPs.

Answer

Deployment

Answer

ConfigMap

Answer

Pod

Question 4

Which TWO of the following are responsibilities of the kube-controller-manager? (Select 2)

Accepted Answer

Ensuring the desired number of pod replicas are running. The kube-controller-manager is responsible for running controller processes that regulate the state of the cluster. Option A is correct because the ReplicaSet controller, which runs inside the kube-controller-manager, continuously monitors the number of running pods and ensures it matches the desired replica count defined in the ReplicaSet or Deployment object. If a pod fails or is deleted, the controller creates a replacement to maintain the desired state.

Answer

Implementing service networking rules

Answer

Storing the cluster state

Answer

Scheduling pods onto nodes

Question 5

Which component is the primary entry point for all administrative tasks and API requests in a Kubernetes control plane?

Accepted Answer

kube-apiserver. The kube-apiserver is the front-end of the Kubernetes control plane and the only component that directly interacts with etcd. All administrative tasks (via kubectl), API requests from pods, and internal control plane components (scheduler, controller-manager) must pass through the kube-apiserver, which validates and processes them before persisting state or triggering actions.

Answer

etcd

Answer

kube-scheduler

Answer

kube-controller-manager

Question 6

What is the smallest deployable unit in Kubernetes that can be created, scheduled, and managed?

Accepted Answer

Pod. A Pod is the smallest and simplest unit in the Kubernetes object model that can be created, scheduled, and managed. It represents a single instance of a running process in the cluster and encapsulates one or more containers with shared storage and network resources. While containers are the underlying runtime, Kubernetes does not schedule containers directly; it schedules Pods as the atomic unit of deployment.

Answer

Deployment

Answer

Node

Answer

Container

Question 7

A developer wants to run a stateless web application with 5 replicas and ensure that when a new version is released, Pods are updated one by one with no downtime. Which Kubernetes resource is best suited?

Accepted Answer

Deployment. A Deployment is the correct resource because it is designed for managing stateless, replicated applications with declarative updates. It supports rolling updates (configurable via `strategy.type: RollingUpdate`), which update Pods one by one, ensuring zero downtime by gradually replacing old Pods with new ones while maintaining the desired replica count.

Answer

Job

Answer

DaemonSet

Answer

StatefulSet

Question 8

You have a web application that needs to read configuration from a file and also access a database password. Which combination of resources should you use to manage these configurations securely?

Accepted Answer

Use ConfigMap for configuration file and Secret for database password. ConfigMap is designed for storing non-confidential configuration data like configuration files, while Secret is specifically for sensitive data such as database passwords. Secrets are base64-encoded and can be encrypted at rest using etcd encryption or KMS, providing a security boundary that ConfigMaps lack. This combination follows Kubernetes best practices for separating configuration from secrets.

Answer

Use ConfigMap for both

Answer

Use PersistentVolume for configuration and environment variables for the password

Answer

Use Secret for both

Question 9

A Pod is in 'CrashLoopBackOff' state. You run 'kubectl logs <pod>' and see an error that the application cannot bind to port 8080 because the port is already in use. What is the most likely cause?

Accepted Answer

Another process inside the container is already using port 8080. The 'CrashLoopBackOff' state indicates the container repeatedly starts, fails, and is restarted by the kubelet. The error message 'port is already in use' means the application inside the container cannot bind to port 8080 because another process within the same container's network namespace is already listening on that port. This is a classic application-level conflict, not a Kubernetes configuration issue.

Answer

The container's health check is misconfigured

Answer

The container runtime is not installed

Answer

The Pod's resource limits are too low

Question 10

A Deployment has a strategy of RollingUpdate with maxSurge=1 and maxUnavailable=0. The Deployment manages 3 replicas. The image is updated. What happens during the update?

Accepted Answer

One new Pod is created, and once it is ready, one old Pod is terminated. This repeats until all Pods are updated.. The RollingUpdate strategy with maxSurge=1 and maxUnavailable=0 ensures that during the update, exactly one new Pod is created above the desired replica count (surge of 1) while keeping all existing Pods running (maxUnavailable=0). Once the new Pod reaches the Ready state, one old Pod is terminated, maintaining the desired 3 replicas throughout the process. This cycle repeats until all Pods are updated, guaranteeing zero downtime.

Answer

All 3 new Pods are created, and then the old ones are terminated all at once

Answer

All 3 old Pods are terminated simultaneously before new ones start

Answer

The update fails because maxUnavailable cannot be 0

Question 11

Which component runs on each worker node and ensures that containers are running as specified in the Pod spec?

Accepted Answer

kubelet. The kubelet is the primary node agent that runs on every worker node in a Kubernetes cluster. It receives PodSpec definitions (via the API server or a file) and ensures that the containers described in those PodSpecs 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 node and pod status back to the control plane.

Answer

kube-proxy

Answer

kube-scheduler

Answer

kube-controller-manager

Question 12

Which TWO of the following are true about Kubernetes Services? (Select 2)

Accepted Answer

Services can distribute traffic across Pods using labels and selectors.. Kubernetes Services use label selectors to identify a set of Pods and then distribute incoming traffic to those Pods. This is the core mechanism that decouples the Service from the specific Pod instances, enabling load balancing and dynamic routing.

Answer

Services automatically handle Pod replication and scaling.

Answer

Services can only expose Pods internally within the cluster.

Answer

Services are required for Pods to have persistent storage.

Question 13

Which TWO of the following components are part of the Kubernetes control plane? (Select 2)

Accepted Answer

kube-apiserver. The Kubernetes control plane is responsible for maintaining the desired state of the cluster and making global decisions. The kube-apiserver is the front-end for the control plane, exposing the Kubernetes API, and etcd is the consistent and highly-available key-value store used as the backing store for all cluster data. Both are essential control plane components.

Answer

container runtime

Answer

kubelet

Answer

kube-proxy

Question 14

What is the purpose of a Service in Kubernetes?

Accepted Answer

To expose a set of pods as a network service with a stable endpoint. A Service in Kubernetes provides a stable network endpoint (IP address and DNS name) to access a set of Pods, which are ephemeral and can be created or destroyed dynamically. It decouples the client from the Pods' IPs by using label selectors to route traffic, enabling reliable communication within the cluster or externally. This is defined in the Kubernetes API as a Service resource, with types like ClusterIP, NodePort, and LoadBalancer.

Answer

To provide persistent storage volumes

Answer

To manage rolling updates of pods

Answer

To store configuration data as key-value pairs

Question 15

A pod is stuck in 'Pending' state. After running 'kubectl describe pod', you see the event: '0/3 nodes are available: 3 Insufficient cpu'. What is the most likely cause?

Accepted Answer

The pod's CPU request exceeds the available CPU on all nodes. The pod is stuck in 'Pending' state because the Kubernetes scheduler cannot find a node that satisfies the pod's resource requirements. The event '0/3 nodes are available: 3 Insufficient cpu' explicitly indicates that every node in the cluster lacks sufficient allocatable CPU capacity to meet the pod's CPU request. This means the sum of CPU requests across all pods on each node, plus the new pod's request, exceeds the node's CPU capacity, causing the scheduler to leave the pod unscheduled.

Answer

The pod is exceeding its memory limit

Answer

The network plugin is not installed

Answer

The container image is too large