KCNA Practice Test 13 — 15 Questions

Question 1

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

Accepted Answer

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

Answer

ServiceAccount

Answer

Secret

Answer

PersistentVolume

Question 2

What is the smallest deployable unit in Kubernetes that you can create and manage?

Accepted Answer

Pod. A Pod is the smallest and simplest unit in the Kubernetes object model that you can create and deploy. It represents a single instance of a running process in your cluster and encapsulates one or more containers with shared storage and network resources. While containers are the actual runtime environments, Kubernetes does not manage containers directly; it manages Pods, which are the atomic unit of scheduling and lifecycle management.

Answer

Service

Answer

Container

Answer

Deployment

Question 3

Which THREE of the following are correct statements about Kubernetes Deployments?

Accepted Answer

A Deployment manages ReplicaSets. A Deployment manages ReplicaSets, which in turn manage Pods. This is the core abstraction: the Deployment controller creates and updates ReplicaSets to achieve the desired state, and each ReplicaSet ensures a specified number of Pod replicas are running. This layered architecture enables features like rolling updates and rollbacks without the Deployment directly interacting with individual Pods.

Answer

Deployments support canary deployments natively

Answer

A Deployment directly manages Pods

Question 4

You have a Service of type ClusterIP named 'my-svc' in the 'default' namespace. A Pod in the same cluster wants to reach this Service using DNS. What is the fully qualified domain name (FQDN) that resolves to the Service's cluster IP?

Accepted Answer

my-svc.default.svc.cluster.local. The standard DNS naming convention for a Kubernetes Service is `..svc.cluster.local`. This FQDN resolves to the ClusterIP of the Service, allowing Pods to discover and communicate with the Service using DNS. The `svc` subdomain is a fixed part of the cluster domain, and `cluster.local` is the default cluster domain suffix.

Answer

my-svc.default.cluster.local

Answer

default.my-svc.svc.cluster.local

Answer

my-svc.svc.default.cluster.local

Question 5

A developer wants to deploy a stateful application that requires stable network identities and persistent storage. Which Kubernetes resource is best suited for this workload?

Accepted Answer

StatefulSet. StatefulSet is the correct choice because it is designed specifically for stateful applications that require stable, unique network identities (via headless Services and ordinal hostnames) and persistent storage (via PersistentVolumeClaims that are retained across Pod rescheduling). Unlike Deployments, StatefulSets guarantee ordered deployment, scaling, and termination, which is essential for databases or message queues.

Answer

Deployment

Answer

DaemonSet

Answer

Job

Question 6

A team runs a stateless web application in Kubernetes. They have a Deployment named 'web-app' with 5 replicas. They want to ensure that a Service named 'web-svc' distributes traffic evenly to all healthy pods. Which type of Service should they use?

Accepted Answer

ClusterIP. A ClusterIP Service is the correct choice because it provides a stable virtual IP address and round-robin load balancing across healthy pods in the Deployment. By default, kube-proxy uses iptables or IPVS rules to distribute traffic evenly to all ready pod endpoints, ensuring stateless web application requests are balanced without requiring external exposure.

Answer

Headless Service

Answer

ExternalName Service

Answer

NodePort

Question 7

What is the smallest deployable unit in Kubernetes?

Accepted Answer

Pod. A 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. While containers are the runtime processes, Kubernetes schedules and manages Pods as atomic units, meaning you cannot deploy a container directly without a Pod wrapper.

Answer

Node

Answer

Container

Answer

Deployment

Question 8

Which TWO of the following are principles of the 12-factor app? (Choose two.)

Accepted Answer

Config. Config is a core principle of the 12-factor app methodology, which mandates strict separation of configuration from code. Configuration (such as database URLs, credentials, or hostnames) must be stored in environment variables, not hardcoded in the application source. This allows the same codebase to be deployed across different environments (development, staging, production) without modification, adhering to the principle of config-driven behavior.

Answer

Monolithic deployment

Answer

Stateful sessions

Answer

Manual provisioning

Question 9

A developer deploys a CronJob that runs a batch job every 5 minutes. After a while, they notice that the job fails with 'DeadlineExceeded' and the pod is stuck in 'PodInitializing' state. What is the most likely reason?

Accepted Answer

A pre-existing InitContainer is failing or stuck. The 'PodInitializing' state indicates that the pod is stuck before its main containers can start, which is typically caused by an InitContainer that is failing or hanging. Since the job fails with 'DeadlineExceeded', the pod's activeDeadlineSeconds (or the CronJob's startingDeadlineSeconds) has been reached while the InitContainer is still running, preventing the main container from executing. This is the most likely reason because InitContainers run sequentially to completion before any main containers start, and a stuck InitContainer blocks the entire pod lifecycle.

Answer

The CronJob schedule is misconfigured

Answer

The container runtime is not installed on the node

Answer

The job's backoffLimit is set too low

Question 10

Which TWO of the following are valid ways to expose a set of pods to traffic from outside the Kubernetes cluster?

Accepted Answer

Service of type NodePort. A Service of type NodePort exposes the service on a static port on each node's IP address. Traffic sent to that port on any cluster node is forwarded to the underlying service, making it accessible from outside the cluster without requiring a cloud load balancer.

Answer

Ingress

Answer

Service of type ExternalName

Answer

Service of type ClusterIP

Question 11

Which TWO of the following are benefits of using containers over virtual machines? (Choose 2)

Accepted Answer

Containers are more lightweight and start faster than VMs. Containers share the host OS kernel and run as isolated processes, making them lightweight and able to start in milliseconds, unlike VMs which require booting a full guest OS. This efficiency stems from container images being mere megabytes compared to gigabytes for VM images, and containers using cgroups and namespaces for resource management rather than a hypervisor.

Answer

Containers require hypervisor software to run

Answer

Containers include a full guest operating system

Answer

Containers provide stronger isolation than VMs

Question 12

Which of the following best describes the purpose of the Cloud Native Computing Foundation (CNCF)?

Accepted Answer

To promote cloud native technologies and host open source projects. The CNCF's primary purpose is to foster the adoption of cloud native technologies by hosting and governing open source projects like Kubernetes, Prometheus, and Envoy. It provides a neutral home for these projects, ensuring they are developed collaboratively under a vendor-neutral governance model. This aligns directly with option A, which captures both the promotional and hosting roles of the foundation.

Answer

To define the 12-factor app methodology

Answer

To provide cloud infrastructure services for enterprises

Answer

To develop and maintain the Kubernetes project exclusively

Question 13

Which control plane component is responsible for assigning pods to nodes?

Accepted Answer

kube-scheduler. The kube-scheduler is the control plane component responsible for assigning pods to nodes. It watches for newly created pods that have no node assignment and selects an optimal node for each pod based on resource requirements, constraints, policies, and data locality. The scheduler does not actually run the pod; it updates the pod's `nodeName` field via the API server, which then triggers the kubelet on the chosen node to launch the pod.

Answer

etcd

Answer

kube-apiserver

Answer

kube-controller-manager

Question 14

A pod is stuck in 'Pending' state. Which of the following is a likely cause?

Accepted Answer

Insufficient cluster resources (CPU/memory) to schedule the pod. A pod stuck in 'Pending' state indicates that the pod has not been scheduled to a node. The most common cause is insufficient cluster resources (CPU/memory), as the Kubernetes scheduler cannot find a node that meets the pod's resource requests. This is a scheduling failure, not a runtime issue.

Answer

The pod's liveness probe failed

Answer

The pod's readiness probe failed

Answer

The container image is missing

Question 15

A developer wants to run a containerized application locally for development. Which tool is most appropriate?

Accepted Answer

Docker Compose. Docker Compose is the most appropriate tool for running a containerized application locally during development because it allows you to define and manage multi-container applications using a simple YAML file. It handles container lifecycle, networking, and volume mounts with a single `docker compose up` command, making it ideal for local development workflows where rapid iteration and simplicity are key.

Answer

CRI-O

Answer

containerd

Answer

Kubernetes