KCNA Kubernetes Fundamentals Practice Test 10 — 15 Questions

Question 1

Drag and drop the steps to create a Kubernetes Namespace and deploy an application into it into the correct order.

Accepted Answer

Create the namespace using 'kubectl create namespace my-namespace', then deploy the application using 'kubectl apply -f deployment.yaml -n my-namespace', then verify the deployment using 'kubectl get pods -n my-namespace'.. First create namespace, then deploy resources specifying that namespace, and verify.

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Deploy the application using 'kubectl apply -f deployment.yaml' without specifying a namespace, then create the namespace using 'kubectl create namespace my-namespace', then verify using 'kubectl get pods'.

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Verify the deployment using 'kubectl get pods', then create the namespace using 'kubectl create namespace my-namespace', then deploy the application using 'kubectl apply -f deployment.yaml -n my-namespace'.

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Create the namespace using 'kubectl create namespace my-namespace', then verify using 'kubectl get pods -n my-namespace', then deploy the application using 'kubectl apply -f deployment.yaml -n my-namespace'.

Question 2

Match each cloud native concept to its definition.

Accepted Answer

Microservices: An architectural style that structures an application as a collection of loosely coupled services.. The correct matches are: Microservices with loosely coupled services, Service Mesh with service-to-service communication, Serverless with cloud provider managing resources, and Orchestration with automated management. Common confusions include swapping definitions between Microservices and Service Mesh, or between Serverless and Orchestration.

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Microservices: A dedicated infrastructure layer for handling service-to-service communication.

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Serverless: The automated configuration, coordination, and management of computer systems.

Question 3

Which Kubernetes control plane component is responsible for storing the cluster state and configuration data?

Accepted Answer

etcd. etcd is the distributed key-value store that serves as Kubernetes' single source of truth for all cluster state and configuration data. It stores objects like Pods, Services, Deployments, and Secrets, and is the only component that holds persistent state. The kube-apiserver reads from and writes to etcd, but etcd itself is the storage backend.

Answer

kube-controller-manager

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kube-apiserver

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kube-scheduler

Question 4

What is the primary purpose of a Kubernetes Service object?

Accepted Answer

To provide a stable IP address and DNS name for a set of Pods. The primary purpose of a Kubernetes Service object is to provide a stable network endpoint (a fixed IP address and DNS name) that abstracts and load-balances traffic across a dynamic set of Pods. Pods are ephemeral and can be rescheduled with new IP addresses, so the Service ensures clients can reliably reach the application without needing to track individual Pod IPs.

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To store configuration data that can be consumed by Pods

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To manage rolling updates and rollbacks for Pods

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To persist data beyond the lifecycle of a Pod

Question 5

You have a Deployment named 'web-app' with 3 replicas. You need to scale it to 5 replicas. Which kubectl command should you use?

Accepted Answer

kubectl scale deployment web-app --replicas=5. The `kubectl scale` command is the correct way to adjust the replica count of an existing Deployment. It directly modifies the `spec.replicas` field in the Deployment's desired state, instructing the ReplicaSet controller to create or delete Pods to match the new count. Option B uses the correct syntax `kubectl scale deployment web-app --replicas=5` to achieve this.

Answer

kubectl create deployment web-app --replicas=5

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kubectl edit deployment web-app --replicas=5

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kubectl describe deployment web-app

Question 6

You need to run a batch job that processes data and then exits. Which Kubernetes resource type is most appropriate for this workload?

Accepted Answer

Job. A Kubernetes Job is designed for workloads that run to completion and then exit, such as batch processing, data transformation, or one-off tasks. Unlike controllers that maintain a desired number of running Pods (like Deployments), Jobs ensure that a specified number of Pods successfully terminate, making them the correct choice for this scenario.

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Deployment

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DaemonSet

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StatefulSet

Question 7

A pod is stuck in 'Pending' state. Which of the following is NOT a common cause for a pod to remain Pending?

Accepted Answer

The container runtime is not functioning on the node. A non-functioning container runtime on a node typically results in pod states like CrashLoopBackOff or Error, not prolonged 'Pending' state. Pending state occurs when a pod cannot be scheduled. Insufficient resources (A), node selector mismatch (B), and unbound PVCs (D) are common causes of scheduling failures that keep a pod in Pending. Container runtime issues affect pod execution after scheduling, not the scheduling process itself. Therefore, C is NOT a common cause for a pod to remain Pending.

Answer

Insufficient CPU or memory resources available in the cluster

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The node selector in the pod spec does not match any node labels

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The pod's PVC is not yet bound to a PV

Question 8

What is the smallest deployable unit in Kubernetes?

Accepted Answer

Pod. A Pod is the smallest and simplest unit in the Kubernetes object model, representing a single instance of a running process in the cluster. It encapsulates one or more containers, shared storage, and a unique network IP, making it the atomic unit of scheduling and deployment.

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Deployment

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Node

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Container

Question 9

Which component is responsible for ensuring that containers are running as specified in a Pod's specification on a node?

Accepted Answer

kubelet. The kubelet is the primary node agent that runs on each node in a Kubernetes cluster. It is responsible for ensuring that containers described in Pod specifications (PodSpecs) are running and healthy. The kubelet watches for Pod assignments from the API server, creates or terminates containers via the container runtime, and continuously reports the node and Pod status back to the control plane.

Answer

Container runtime

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kube-proxy

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kube-scheduler

Question 10

You need to store a database password securely and expose it to a Pod as an environment variable. Which Kubernetes resource should you use?

Accepted Answer

Secret. A Secret is the correct Kubernetes resource for storing sensitive data like database passwords because it encodes the value in base64 and can be injected into a Pod as an environment variable. Unlike ConfigMaps, Secrets are designed for confidential information and support optional encryption at rest when etcd is configured accordingly.

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Service

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PersistentVolumeClaim

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ConfigMap

Question 11

You have a Deployment with image: myapp:v1. You update the image to myapp:v2 using 'kubectl set image deployment/myapp myapp=myapp:v2'. The rollout status shows 'Waiting for rollout to finish: 0 out of 3 new replicas have been updated...'. What is the most likely cause of this behavior?

Accepted Answer

The new image myapp:v2 does not exist or cannot be pulled from the registry. The rollout is stuck waiting for new replicas to become ready, which typically happens when the container image cannot be pulled. The message '0 out of 3 new replicas have been updated' indicates that the ReplicaSet is attempting to create Pods with the new image, but the Pods are failing to start. The most common cause is that the image tag 'myapp:v2' does not exist in the registry or cannot be accessed due to authentication or network issues, preventing the kubelet from pulling it.

Answer

The command syntax is incorrect; you should use 'kubectl set image deployment/myapp myapp:v2'

Answer

The new Pods are crashing due to a missing command

Answer

The Deployment's update strategy is set to 'Recreate'

Question 12

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

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

Question 13

Which THREE of the following are valid use cases for Kubernetes Namespaces? (Select 3)

Accepted Answer

To enforce resource quotas and limits on the resources within the namespace. Option A is correct because Namespaces are the scope at which Kubernetes ResourceQuota and LimitRange objects are applied, letting administrators cap aggregate CPU/memory/storage consumption and enforce per-container defaults for all workloads inside that namespace. Option B is correct because a single cluster can host distinct dev, staging, and production environments as separate Namespaces, each with its own objects, RBAC, and quotas, without provisioning additional clusters. Option E is correct because Namespaces provide logical partitioning so multiple teams or projects can share one cluster while keeping their Pods, Services, ConfigMaps, and Secrets scoped and access-controlled independently. Option C is incorrect because Nodes and PersistentVolumes are cluster-scoped resources that live outside any Namespace and cannot be isolated by one. Option D is incorrect because Namespaces are purely a logical/API-scoping construct and have no effect on the data plane, so they do not reduce network latency between Pods.

Answer

To isolate cluster-wide resources such as Nodes and PersistentVolumes

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To improve performance by reducing network latency between Pods

Question 14

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

Accepted Answer

Deployments support rolling updates and rollbacks. Option A is correct because a Deployment's pod template can be updated declaratively, and the Deployment controller performs a rolling update by creating a new ReplicaSet and gradually scaling it up while scaling the old one down, with `kubectl rollout undo` providing rollback to a previous revision. Option D is correct because a Deployment does not manage Pods directly; it creates and manages ReplicaSets, which in turn maintain the desired number of Pod replicas, and each template change produces a new ReplicaSet revision. Option B is wrong because running one Pod copy per node is the job of a DaemonSet, not a Deployment. Option C is wrong because run-to-completion batch workloads are handled by Jobs (or CronJobs), whereas Deployments are intended for long-running stateless services. Option E is wrong because stable network identities and per-Pod DNS names are provided by a headless Service (typically with a StatefulSet), not by a Deployment.

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

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Deployments provide stable network identities for Pods

Question 15

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