KCNA Kubernetes Fundamentals Practice Test 13 — 15 Questions

Question 1

A user wants to run a one-time batch job that runs to completion. Which Kubernetes resource should they use?

Accepted Answer

Job. A Kubernetes Job is the correct resource for a one-time batch job that runs to completion. Unlike controllers designed for long-running processes, a Job creates one or more Pods and ensures they successfully terminate, making it ideal for finite tasks like data processing or backups.

Answer

StatefulSet

Answer

DaemonSet

Answer

Deployment

Question 2

A developer creates a Service of type ClusterIP in namespace 'default'. They attempt to reach the Service from another pod in the same namespace using the Service name 'my-svc'. The connection fails. What is the most likely cause?

Accepted Answer

The cluster DNS service (CoreDNS) is not running or misconfigured. The most likely cause is that the cluster DNS service (CoreDNS) is not running or misconfigured. When a pod attempts to reach a Service by its DNS name (e.g., 'my-svc'), Kubernetes relies on CoreDNS to resolve that name to the ClusterIP. If CoreDNS is down, misconfigured, or the pod's DNS resolver is not pointing to it, the name resolution fails, causing the connection to fail even if the Service itself is correctly configured.

Answer

The Service port does not match the container port

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The Service type should be NodePort

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The Service selector does not match any pod labels

Question 3

Which of the following is a correct way to assign a pod to a specific node using a nodeSelector?

Accepted Answer

spec: nodeSelector: disktype: ssd. `nodeSelector` is a simple pod scheduling constraint that uses a key-value pair in the `spec.nodeSelector` field to match node labels. The correct YAML syntax is `spec: nodeSelector: disktype: ssd`, where `disktype` is the label key and `ssd` is the value, ensuring the pod is scheduled only on nodes with that exact label.

Answer

spec: affinity: nodeAffinity: requiredDuringSchedulingIgnoredDuringExecution: nodeSelectorTerms: ...

Answer

spec: nodeName: "node1"

Answer

spec: nodeSelector: [disktype: ssd]

Question 4

A pod has resource requests set to 'cpu: 500m' and 'memory: 256Mi'. The node has 2 CPU cores and 4Gi memory. How many pods with the same resource requests can be scheduled on that node, assuming no other pods?

Accepted Answer

4. Each pod requests 0.5 CPU cores (500m) and 256 MiB of memory. The node has 2 CPU cores, so the CPU limit allows 2 / 0.5 = 4 pods. The node has 4 GiB of memory (4096 MiB), so the memory limit allows 4096 / 256 = 16 pods. The tighter constraint is CPU, which permits exactly 4 pods. Option B is correct.

Answer

2

Answer

8

Answer

16

Question 5

Which of the following kubectl commands would you use to apply a manifest file and also save it for later updates?

Accepted Answer

kubectl apply -f manifest.yaml. `kubectl apply` uses a declarative approach: it creates the resource if it doesn't exist and updates it if it does, while also storing the last-applied configuration as an annotation (`kubectl.kubernetes.io/last-applied-configuration`). This allows future `apply` calls to perform a three-way merge diff (current live state, last-applied config, and new manifest) to intelligently update the resource, making it the standard for managing manifests that need ongoing updates.

Answer

kubectl create -f manifest.yaml

Answer

kubectl patch -f manifest.yaml

Answer

kubectl replace -f manifest.yaml

Question 6

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

Accepted Answer

etcd. etcd is a distributed key-value store that holds the cluster's state and configuration data, making it a core control plane component. The kube-apiserver is the front-end for the Kubernetes control plane, exposing the Kubernetes API and handling all RESTful requests to manage the cluster. Both are essential for cluster management and orchestration, not for running application workloads.

Answer

kube-proxy

Answer

kubelet

Answer

Container runtime

Question 7

Which THREE of the following are valid types of Kubernetes Services? (Select THREE)

Accepted Answer

LoadBalancer. (LoadBalancer) is correct because it exposes the Service externally using a cloud provider's load balancer, which automatically routes external traffic to the NodePort and ClusterIP Services. This is one of the four standard Kubernetes Service types defined in the core API.

Answer

InternalIP

Answer

ExternalName

Question 8

Which TWO of the following are true about Pod resource limits? (Select TWO)

Accepted Answer

CPU limits are enforced using CFS quotas. Kubernetes enforces CPU limits using Completely Fair Scheduler (CFS) quotas. When a CPU limit is set, the kubelet configures the container's cgroup `cpu.cfs_quota_us` parameter, which restricts the total CPU time the container can consume over a CFS period (default 100ms). This ensures the container cannot exceed its specified CPU limit, even if the node has idle CPU resources.

Answer

A container can use more memory than its limit if the node has free memory

Answer

Memory limits are soft and can be exceeded temporarily

Answer

Setting CPU limits guarantees that a container will always get that much CPU

Question 9

A Deployment named 'web-app' is configured with replicas: 3. You update the container image. Which Kubernetes object directly manages the pods during the rolling update?

Accepted Answer

ReplicaSet. When a Deployment is updated (e.g., container image change), it creates a new ReplicaSet to manage the new pods and scales down the old ReplicaSet. The ReplicaSet is the Kubernetes object that directly owns and manages the pods during the rolling update, ensuring the desired number of replicas are running at each step.

Answer

StatefulSet

Answer

DaemonSet

Answer

Job

Question 10

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

Accepted Answer

Pod. The Pod is the smallest and simplest unit in the Kubernetes object model. It represents a single instance of a running process in the cluster and encapsulates one or more containers, shared storage, and a unique network IP. While containers are the runtime units, Kubernetes does not manage containers directly; it manages Pods, which are the atomic deployable and schedulable entities.

Answer

Deployment

Answer

Node

Answer

Container

Question 11

A Service of type ClusterIP has been created, but pods in the same namespace cannot reach it by its DNS name. The Service selector matches the pods. What is a likely cause?

Accepted Answer

The kube-dns or CoreDNS pod is not running. The DNS name resolution for a ClusterIP Service relies on the cluster's DNS service (kube-dns or CoreDNS). If the DNS pod is not running, the Service's DNS record (e.g., ..svc.cluster.local) cannot be resolved, even if the Service itself is properly configured and the pods match the selector. Without DNS, pods must use the Service's ClusterIP directly, which is not the expected behavior for name-based access.

Answer

The Service YAML does not specify a port

Answer

The Service is not exposed on a node port

Answer

The pods are using an incorrect container runtime

Question 12

You need to store a sensitive database password in Kubernetes. Which 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 data in base64 and is designed to be consumed securely by pods, with access controlled via RBAC. Unlike ConfigMaps, Secrets are not intended for non-sensitive configuration and provide a layer of separation for confidential information.

Answer

PersistentVolume

Answer

ConfigMap

Answer

ServiceAccount

Question 13

What is the purpose of a Namespace in Kubernetes?

Accepted Answer

To logically isolate resources like pods and services. Namespaces in Kubernetes provide a mechanism for logically isolating resources such as Pods, Services, and Deployments within a cluster. They enable multiple virtual clusters to coexist on the same physical cluster, allowing for resource scoping, access control, and organization by team or environment (e.g., dev, staging, prod). This isolation is fundamental to multi-tenancy and resource management in Kubernetes.

Answer

To assign IP addresses to services

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To limit the number of pods that can be created

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To provide DNS names for pods

Question 14

You create a Pod with a liveness probe that uses an HTTP GET on port 8080, path /healthz. The probe fails after the container starts. What will happen to the Pod?

Accepted Answer

The container will be restarted automatically. A liveness probe is designed to determine if a container is still running properly. When an HTTP GET liveness probe fails, kubelet considers the container unhealthy and automatically restarts it according to the Pod's restart policy (defaulting to Always). This ensures the container can recover from transient failures without manual intervention.

Answer

The Pod will be marked as Unhealthy and removed from Service endpoints

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The Pod will be evicted from the node

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The Pod will be deleted and recreated on a different node

Question 15

Which API version is correct for a Deployment in modern Kubernetes (v1.29+)?

Accepted Answer

apiVersion: apps/v1. In modern Kubernetes (v1.29+), the `apps/v1` API version is the stable and recommended version for the Deployment resource. The `apps/v1` API has been the default since Kubernetes 1.9, and all older beta versions (e.g., `apps/v1beta2`, `extensions/v1beta1`) have been removed as of Kubernetes 1.16. Using `apps/v1` ensures compatibility with current cluster features and avoids deprecation warnings.

Answer

apiVersion: extensions/v1beta1

Answer

apiVersion: v1

Answer

apiVersion: apps/v1beta2