Linux Foundation CKA Online Practice Questions and Exam Preparation

Linux Foundation CKA Online Questions & Answers

• Question 41:

  SIMULATION

  Ensure a single instance of pod nginx is running on each node of the Kubernetes cluster where nginx also represents the Image name which has to be used. Do not override any taints currently in place. Use DaemonSet to complete this task and use ds-kusc00201 as DaemonSet name.

  Correct Answer. Check the answer in explanation.
  Check the answer in explanation.

  ---

  Solution:

  

  

  

  

• Question 42:

  SIMULATION

  You must connect to the correct host.

  Failure to do so may result in a zero score.

  [candidate@base] $ ssh cka000059

  Context

  A kubeadm-provisioned cluster was migrated to a new machine. It needs configuration changes to run successfully.

  Task

  Fix a single-node cluster that got broken during machine migration.

  First, identify the broken cluster components and investigate what breaks them.

  The decommissioned cluster used an external etcd server.

  Next, fix the configuration of all broken cluster components.

  Correct Answer. Check the answer in explanation.
  Check the answer in explanation.

  ---

  Explanation Task Summary

  SSH into node: cka000059

  Cluster was migrated to a new machine

  It uses an external etcd server

  Identify and fix misconfigured components

  Bring the cluster back to a healthy state

  Step-by-Step Solution:

  Step 1: SSH into the correct host

  ssh cka000059

  Step 2: Check the cluster status

  Run:

  kubectl get nodes

  If it fails, the kubelet or kube-apiserver is likely broken.

  Check kubelet status:

  sudo systemctl status kubelet

  Also, check pod statuses in the control plane:

  sudo crictl ps -a | grep kube

  or:

  docker ps -a | grep kube

  Look especially for failures in kube-apiserver or kube-controller-manager.

  Step 3: Inspect the kube-apiserver manifest

  Since this is a kubeadm-based cluster, manifests are in:

  ls /etc/kubernetes/manifests

  Open kube-apiserver.yaml:

  sudo nano /etc/kubernetes/manifests/kube-apiserver.yaml

  Look for the --etcd-servers= flag. If the external etcd endpoint has changed (likely, due to migration), this needs to be fixed.

  Example of incorrect configuration:

  --etcd-servers=https://192.168.1.100:2379

  If the IP has changed, update it to the correct IP or hostname of the external etcd server.

  Also ensure the correct client certificate and key paths are still valid:

  --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt

  --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key If the files are missing or the path is wrong due to migration, correct those as well.

  Step 4: Save and exit, and let the static pod restart

  Static pod changes will be picked up automatically by the kubelet (watch for /etc/kubernetes/manifests changes).

  Check again:

  docker ps | grep kube-apiserver # or crictl ps | grep kube-apiserver

  Step 5: Confirm API is healthy

  Once kube-apiserver is up, try:

  kubectl get componentstatuses kubectl get nodes If these commands work and return valid statuses, the control plane is functional again.

  Step 6: Check controller-manager and scheduler (optional)

  If still broken, check the other static pods in /etc/kubernetes/manifests/ and correct paths if necessary. Also verify that /etc/kubernetes/kubelet.conf and /etc/kubernetes/admin.conf are present and valid.

  Command Summary

  ssh cka000059

  # Check system and kubelet sudo systemctl status kubelet

  docker ps -a | grep kube # or crictl ps -a | grep kube

  # Check manifests ls /etc/kubernetes/manifests sudo nano /etc/kubernetes/manifests/kube-apiserver.yaml

  # Fix --etcd-servers and certificate paths if needed

  # Watch pods restart and confirm: kubectl get nodes kubectl get componentstatuses

• Question 43:

  SIMULATION

  Create a busybox pod that runs the command "env" and save the output to "envpod" file

  Correct Answer. Check the answer in explanation.
  Check the answer in explanation.

  ---

  kubectl run busybox --image=busybox --restart=Never -rm -it -- env>; envpod.yaml

• Question 44:

  SIMULATION

  Create a pod as follows: Name: non-persistent-redis container Image: redis Volume with name: cache-control Mount path: /data/redis The pod should launch in the staging namespace and the volume must not be persistent.

  Correct Answer. Check the answer in explanation.
  Check the answer in explanation.

  ---

  Solution:

  

  

  

• Question 45:

  SIMULATION

  Given a partially-functioning Kubernetes cluster, identify symptoms of failure on the cluster.

  Determine the node, the failing service, and take actions to bring up the failed service and restore the health of the cluster. Ensure that any changes are made permanently.

  You can ssh to the relevant I nodes (bk8s-master-0 or bk8s-node-0) using:

  [student@node-1] $ ssh

  You can assume elevated privileges on any node in the cluster with the following command:

  [student@nodename] $ | sudo -i

  Correct Answer. Check the answer in explanation.
  Check the answer in explanation.

  ---

  Solution:

  

  

• Question 46:

  SIMULATION

  

  Task

  First, create a snapshot of the existing etcd instance running at https://127.0.0.1:2379, saving the snapshot to /srv/data/etcd-snapshot.db.

  

  Next, restore an existing, previous snapshot located at /var/lib/backup/etcd-snapshot-previous.db

  

  Correct Answer. Check the answer in explanation.
  Check the answer in explanation.

  ---

  Solution:

  

• Question 47:

  SIMULATION

  

  Task

  Create a new HorizontalPodAutoscaler (HPA) named apache-server in the autoscale namespace.

  This HPA must target the existing Deployment called apache-server in the same autoscale namespace.

  Set the HPA to:

  Target 50% CPU usage per Pod

  Have at least 1 Pod

  Have no more than 4 Pods

  Set the downscale stabilization window to 30 seconds

  Correct Answer. Check the answer in explanation.
  Check the answer in explanation.

  ---

  Step 1: SSH into the node

  ssh cka000050

  Step 2: Create the HPA with required CPU target and min/max pods

  kubectl autoscale deployment apache-server \

  --cpu-percent=50 \

  --min=1 \

  --max=4 \

  -n autoscale

  Step 3: Patch to add the downscale stabilization window (30s)

  kubectl patch hpa apache-server \

  -n autoscale \

  --type='merge' \

  -p '{"spec": {"behavior": {"scaleDown": {"stabilizationWindowSeconds": 30}}}}'

  Step 4: Verify

  kubectl get hpa apache-server -n autoscale kubectl describe hpa apache-server -n autoscale Confirm:

  Target deployment is apache-server CPU utilization target: 50% Min pods: 1 Max pods: 4 scaleDown.stabilizationWindowSeconds: 30 is present

• Question 48:

  SIMULATION

  

  Schedule a Pod as follows:

  1. Name: kucc1

  2. App Containers: 2

  3. Container Name/images: redis consul

  Correct Answer. Check the answer in explanation.
  Check the answer in explanation.

  ---

  apiVersion: v1 kind: Pod metadata:

  name: kucc1 spec:

  containers:

  name: redis

  image: redis

  name: consul

  image: hashicorp/consul:latest

• Question 49:

  SIMULATION

  You must connect to the correct host.

  Failure to do so may result in a zero score.

  [candidate@base] $ ssh cka000054

  Context:

  Your cluster's CNI has failed a security audit. It has been removed. You must install a new CNI that can enforce network policies.

  Task

  Install and set up a Container Network Interface (CNI) that meets these requirements:

  Pick and install one of these CNI options:

  Flannel version 0.26.1

  Manifest:

  https://github.com/flannel-io/flannel/releases/download/v0.26.1/kube-flannel.yml

  Calico version 3.28.2

  Manifest:

  https://raw.githubusercontent.com/projectcalico/calico/v3.28.2/manifests/tigera-operator.yaml

  Correct Answer. Check the answer in explanation.
  Check the answer in explanation.

  ---

  Solution:

  

  

• Question 50:

  SIMULATION

  

  Task

  Given an existing Kubernetes cluster running version 1.20.0, upgrade all of the Kubernetes control plane and node components on the master node only to version 1.20.1.

  Be sure to drain the master node before upgrading it and uncordon it after the upgrade.

  

  You are also expected to upgrade kubelet and kubectl on the master node.

  

  Correct Answer. Check the answer in explanation.
  Check the answer in explanation.

  ---

  Solution: