KCNA Kubernetes Fundamentals Practice Test 16 — 15 Questions

Question 1

You want to create a new Namespace called 'staging' and apply a ResourceQuota to it. Which of the following YAML snippets correctly defines a ResourceQuota that limits total memory to 10Gi and total CPU to 5 cores in namespace 'staging'?

Accepted Answer

apiVersion: v1
kind: ResourceQuota
metadata:
  name: staging-quota
  namespace: staging
spec:
  hard:
    limits.cpu: "5"
    limits.memory: 10Gi. ResourceQuota uses 'spec.hard' with resource names like 'limits.cpu' and 'limits.memory'.

Answer

apiVersion: v1
kind: ResourceQuota
metadata:
  name: staging-quota
  namespace: staging
spec:
  hard:
    requests.cpu: "5"
    requests.memory: 10Gi

Answer

apiVersion: v1
kind: LimitRange
metadata:
  name: staging-limits
  namespace: staging
spec:
  limits:
  - default:
      cpu: 5
      memory: 10Gi
    defaultRequest:
      cpu: 1
      memory: 1Gi

Answer

apiVersion: v1
kind: ResourceQuota
metadata:
  name: staging-quota
spec:
  hard:
    cpu: 5
    memory: 10Gi

Question 2

Which two of the following are benefits of using Kubernetes for container orchestration? (Select TWO.)

Accepted Answer

Self-healing: automatically restarts failed containers. Kubernetes provides self-healing and automated scaling.

Answer

Integrated continuous integration pipeline

Answer

Automatic code compilation

Answer

Built-in database management

Question 3

Which two components are part of the Kubernetes control plane? (Select TWO.)

Accepted Answer

kube-apiserver. The Kubernetes control plane manages the cluster and makes global decisions. kube-apiserver is the front-end for the control plane, exposing the Kubernetes API for all interactions. etcd is a consistent and highly-available key-value store used as Kubernetes' backing store for all cluster data, making it a core control plane component.

Answer

container runtime

Answer

kube-proxy

Answer

kubelet

Question 4

Which three of the following are valid ways to interact with the Kubernetes API? (Select THREE.)

Accepted Answer

Using a Kubernetes client library (e.g., client-go). kubectl, curl, and client libraries are common API interaction methods.

Answer

Using the 'kubeadm' command

Answer

Using the Docker CLI

Question 5

A pod in the 'production' namespace is in a CrashLoopBackOff state. The pod has been running successfully for several days. You run 'kubectl describe pod app-pod -n production' and see the message: 'OOMKilled'. What is the MOST appropriate action to resolve this issue?

Accepted Answer

Increase the memory limit in the pod's container resource specification. Option B is correct. OOMKilled means the container exceeded its memory limit and was killed by the kernel OOM killer. The solution is to increase the memory limit in the container's resource specification. Option A would not help — restarting the pod without addressing the root cause will result in the same failure. Option C addresses CPU, not memory. Option D (deleting the namespace) is destructive and unnecessary.

Answer

Delete the namespace and redeploy all workloads

Answer

Delete and recreate the pod to clear the crash loop

Answer

Increase the CPU request for the container

Question 6

Which Kubernetes control plane component is responsible for maintaining the desired state of the cluster by running controller loops?

Accepted Answer

kube-controller-manager. The kube-controller-manager is the control plane component that runs controller loops, which are continuous processes that watch the shared state of the cluster through the kube-apiserver and make changes to drive the current state toward the desired state. Each controller (e.g., ReplicaSet, Node, Deployment) is a separate loop that handles a specific aspect of cluster management, ensuring that the actual cluster state matches the desired configuration defined in the API objects.

Answer

etcd

Answer

kube-apiserver

Answer

kube-scheduler

Question 7

You need to run a stateless web application with three replicas, and you want to ensure that if a pod fails, it is automatically replaced. Which Kubernetes resource should you use?

Accepted Answer

Deployment. A Deployment manages ReplicaSets and provides declarative updates, including self-healing by recreating failed pods. A DaemonSet runs a pod on each node, a Job runs a batch task, and a StatefulSet is for stateful applications.

Answer

DaemonSet

Answer

Job

Answer

StatefulSet

Question 8

A developer created a Deployment with 5 replicas. After applying the manifest, only 3 pods are Running; the other 2 are Pending. Which is the MOST likely cause?

Accepted Answer

The nodes do not have enough available CPU or memory to schedule the additional pods. Pending pods typically indicate that the scheduler cannot find a suitable node. The most common reason is insufficient resources (CPU or memory) on the nodes. Image pull errors or readiness probe failures would result in CrashLoopBackOff or not Ready, not Pending. Network policies do not prevent pod scheduling.

Answer

The readiness probe is failing

Answer

A NetworkPolicy is blocking traffic to the pods

Answer

The container image is misspelled

Question 9

What is the primary purpose of a Kubernetes Service?

Accepted Answer

To provide a stable network endpoint for a set of pods. A Service provides a stable IP address and DNS name for a set of pods, enabling load-balanced access even as pods are created and destroyed. It does not store configuration data, manage updates, or replace kube-proxy.

Answer

To implement network routing rules on each node

Answer

To manage rolling updates of applications

Answer

To store configuration data as key-value pairs

Question 10

You want to view the logs of a container named 'app' inside a pod named 'web-pod-7d4f8'. Which kubectl command should you use?

Accepted Answer

kubectl logs web-pod-7d4f8 -c app. kubectl logs is used to fetch container logs. When a pod has multiple containers, the -c flag specifies the container. Options A and B have incorrect syntax; option D is for running commands in a container, not viewing logs.

Answer

kubectl exec web-pod-7d4f8 -c app -- logs

Answer

kubectl log web-pod-7d4f8 --container app

Answer

kubectl logs web-pod-7d4f8 app

Question 11

A cluster administrator needs to ensure that a Deployment named 'frontend' in namespace 'web' is updated with a new image version using a rolling update strategy. The current deployment has 4 replicas. The administrator runs: kubectl set image deployment/frontend frontend=nginx:1.21 -n web. Which of the following describes the expected behavior?

Accepted Answer

The Deployment will create a new ReplicaSet and gradually replace old pods with new ones. The 'kubectl set image' command triggers a rolling update on the Deployment. By default, the Deployment's strategy is RollingUpdate, which updates pods gradually. The ReplicaSet is updated, and old pods are scaled down while new ones are scaled up. Option B incorrectly describes a Recreate update. Option C is false because the Deployment is updated in place. Option D is incorrect because the image is changed for the 'frontend' container.

Answer

All existing pods will be deleted immediately and new pods will be created with the new image

Answer

The command will fail because you cannot update a Deployment using kubectl set image

Answer

The Deployment's image will be updated, but only the container named 'app' will be affected

Question 12

Which of the following is a worker node component responsible for ensuring that containers are running in a pod as specified in the pod's spec?

Accepted Answer

kubelet. The kubelet is the primary node agent that runs on each worker node. It receives PodSpecs (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 as required.

Answer

kube-scheduler

Answer

kube-proxy

Answer

etcd

Question 13

You need to create a ConfigMap from a file named 'app.properties'. Which kubectl command should you use?

Accepted Answer

kubectl create configmap my-config --from-file=app.properties. kubectl create configmap supports the --from-file flag to create a ConfigMap from a file. Option A uses an invalid flag; option B has incorrect flag; option D uses --from-env-file which is for loading environment variables from a file, but the question asks for a ConfigMap from a file generally.

Answer

kubectl create configmap my-config --from-literal=app.properties

Answer

kubectl create configmap my-config --file=app.properties

Answer

kubectl create configmap my-config --from-env-file=app.properties

Question 14

A pod has resource requests: cpu: 250m, memory: 512Mi and limits: cpu: 500m, memory: 1Gi. If the container tries to use 600m CPU and 700Mi memory, what will happen?

Accepted Answer

The container will be throttled for CPU, but will not be killed because memory is within limits. If a container exceeds its CPU limit, it gets throttled (not killed). If it exceeds its memory limit, it is killed (OOMKilled). Here, CPU usage 600m exceeds limit 500m -> throttled; memory usage 700Mi is below limit 1Gi -> no OOM.

Answer

The container will be allowed to use the extra resources because limits are only soft constraints

Answer

The container will be throttled for CPU and may be terminated if it continues to exceed the limit

Answer

The container will be killed immediately because it exceeded its CPU limit

Question 15

Which component of the control plane is the only one that directly interacts with etcd?

Accepted Answer

kube-apiserver. The kube-apiserver is the only component that communicates with etcd. All other components (scheduler, controller-manager) interact with etcd indirectly through the API server.

Answer

kube-controller-manager

Answer

kube-scheduler

Answer

kubelet