KCNA Kubernetes Fundamentals Practice Test 11 — 15 Questions

Question 1

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

Accepted Answer

kubectl logs web-pod -c nginx. The `kubectl logs` command retrieves container logs from a Pod, and when a Pod contains multiple containers, the `-c` flag is required to specify which container's logs to view. Here, `kubectl logs web-pod -c nginx` explicitly targets the 'nginx' container within the 'web-pod' Pod, which is the standard Kubernetes API approach for fetching container stdout/stderr streams.

Answer

kubectl logs web-pod nginx

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kubectl describe pod web-pod

Answer

kubectl exec web-pod -- cat /var/log/nginx/access.log

Question 2

Which TWO of the following statements about Kubernetes Deployments are correct? (Select 2)

Accepted Answer

Deployments support rolling updates and rollbacks. A is correct because Deployments provide a declarative update mechanism that supports rolling updates, where Pods are gradually replaced with new ones, and rollbacks, which revert the Deployment to a previous revision. This is achieved through the Deployment controller managing ReplicaSets, allowing seamless transitions between versions without downtime.

Answer

Deployments ensure that a copy of a Pod runs on each node in the cluster

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Deployments are used for batch processing jobs that run to completion

Answer

Deployments provide stable network identities for Pods

Question 3

What is the primary purpose of Kubernetes?

Accepted Answer

To orchestrate containers across a cluster of machines. Kubernetes is a container orchestration platform designed to automate the deployment, scaling, and management of containerized applications across a cluster of machines. Its primary purpose is to abstract the underlying infrastructure and provide declarative management of container workloads, ensuring desired state convergence through controllers like the ReplicaSet and Deployment.

Answer

To provide a graphical user interface for managing containers

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To replace Docker as a container runtime

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To provide a virtual machine management platform

Question 4

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

Accepted Answer

etcd. etcd is the distributed key-value store that acts as the single source of truth for the entire Kubernetes cluster. It stores all cluster state data, including configuration, secrets, and the desired state of every object, ensuring consistency and durability. The kube-apiserver is the only component that directly interacts with etcd, enforcing a strict serialization of writes to prevent corruption.

Answer

kube-scheduler

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kube-controller-manager

Answer

kube-apiserver

Question 5

A pod is stuck in Pending state. Which of the following is the MOST likely reason?

Accepted Answer

There are insufficient resources on any available node. Pending means the pod has not been scheduled to a node, often due to insufficient resources or node constraints.

Answer

The pod is still being initialized

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The container image is missing

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The pod has crashed and is restarting

Question 6

What does the 'kubectl get pods' command display?

Accepted Answer

A list of all pods in the current namespace. The 'kubectl get pods' command lists all pods in the current namespace, providing a summary of their status, restarts, and age. This is the default behavior without specifying a namespace or pod name, making it the primary command for pod discovery and health checks.

Answer

Detailed information about a specific pod

Answer

The YAML definition of a pod

Answer

The logs of all pods

Question 7

A cluster administrator notices that a Deployment's pods are not receiving traffic as expected. The Service selector matches the pod labels. What is a possible cause?

Accepted Answer

The pods have a failing readiness probe. A failing readiness probe removes the pod's endpoint from the Service's EndpointSlice, so the Service stops routing traffic to that pod even though the pod is running and its labels match the Service selector. This is the most direct reason why a Deployment's pods would not receive traffic despite correct label matching.

Answer

The pods have a liveness probe that fails

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The Deployment replicas are set to zero

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The Service type is NodePort

Question 8

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

Accepted Answer

It implements part of the Kubernetes Service concept by managing network rules. kube-proxy runs on each worker node and is responsible for implementing the Kubernetes Service abstraction by managing network rules (e.g., iptables, IPVS, or userspace mode). It watches the API server for Service and EndpointSlice changes and configures local packet filtering or forwarding rules to route traffic to the correct backend pods, enabling load balancing and service discovery.

Answer

It ensures the desired number of pods are running

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It runs the container runtime

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It reports node status to the control plane

Question 9

What is the smallest deployable unit in Kubernetes?

Accepted Answer

Pod. The Pod is the smallest deployable unit in Kubernetes because it 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 wraps them into Pods, which are the atomic unit of scheduling and execution. This design ensures that co-located containers (e.g., a sidecar and its main app) can communicate via localhost and share resources without additional orchestration.

Answer

Node

Answer

Container

Answer

Deployment

Question 10

Which three of the following are valid methods to create or update resources in Kubernetes? (Choose three.)

Accepted Answer

kubectl apply -f manifest.yaml. `kubectl apply -f manifest.yaml` is correct because it uses a declarative approach to create or update resources by applying a configuration file, performing a three-way merge between the local file, the current live object, and the last-applied annotation. `kubectl create -f manifest.yaml` is also correct because it creates resources from a file or stdin, though it will fail if the resource already exists. Using the Kubernetes REST API directly (via HTTP requests like POST for create and PUT for update) is another valid method. `kubectl update` is not a valid kubectl command; the correct imperative commands for updates are `kubectl edit` or `kubectl patch`. `kubectl replace -f manifest.yaml` is an imperative command that will fail if the resource does not exist and is not recommended for general resource management.

Answer

kubectl update -f manifest.yaml

Answer

kubectl replace -f manifest.yaml

Question 11

Which two scenarios would benefit from using a StatefulSet instead of a Deployment? (Choose two.)

Accepted Answer

An application that requires persistent storage unique to each instance. StatefulSets are designed for applications that require unique, persistent storage per Pod. Each Pod in a StatefulSet gets its own PersistentVolumeClaim (PVC) that is not shared, ensuring data isolation and durability even if the Pod is rescheduled. This is essential for stateful workloads like databases or message queues.

Answer

A batch job that runs once and exits

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A stateless web application that can scale horizontally

Answer

A microservice that can use any available node

Question 12

What is the primary purpose of Kubernetes?

Accepted Answer

To orchestrate containers across a cluster of machines. Kubernetes is a container orchestration platform designed to automate the deployment, scaling, and management of containerized applications across a cluster of machines. Its primary purpose is to ensure that containers run reliably and efficiently by handling scheduling, load balancing, self-healing, and rolling updates, which is why option D is correct.

Answer

To provide a graphical interface for managing containers

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To replace virtual machines with containers

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To compile container images from source code

Question 13

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

Accepted Answer

Pod. Pod is the smallest deployable unit in Kubernetes because it 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 as atomic units, making the Pod the fundamental building block of deployment.

Answer

Service

Answer

Container

Answer

Node

Question 14

A pod has a liveness probe that returns failure. What action will Kubernetes take?

Accepted Answer

The container will be restarted. When a liveness probe fails, Kubernetes interprets this as the container being in a deadlock or unresponsive state from which it cannot recover without a restart. The kubelet on the node where the pod is running directly restarts the container according to the pod's restart policy (defaulting to Always). This is a container-level action, not a pod-level action, so the pod itself remains on the same node.

Answer

The service endpoint will be removed

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The pod will be deleted

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The pod will be rescheduled to another node

Question 15

Which Kubernetes object is used to store non-sensitive configuration data that can be consumed by pods?

Accepted Answer

ConfigMap. ConfigMap is the correct Kubernetes object for storing non-sensitive configuration data, such as environment variables, command-line arguments, or configuration files, that can be consumed by pods. Unlike Secrets, ConfigMaps store data in plaintext and are designed for configuration that does not require encryption, making them ideal for application settings that are not confidential.

Answer

Secret

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ServiceAccount

Answer

PersistentVolume