CKA Troubleshooting Practice Test 13 — 15 Questions

Question 1

Which TWO of the following are valid causes for a pod to be in CrashLoopBackOff?

Accepted Answer

The livenessProbe fails causing a restart. CrashLoopBackOff occurs when a container exits repeatedly. Common causes include application errors and misconfigured probes.

Answer

The node is out of memory

Answer

The image pull secret is missing

Answer

The container is using too much CPU

Question 2

Which THREE of the following are valid steps to troubleshoot DNS issues in a Kubernetes cluster?

Accepted Answer

Run 'kubectl exec <pod> -- nslookup kubernetes.default'. To troubleshoot DNS, you can check the DNS pod logs, test resolution from a pod, and verify the DNS service endpoints.

Answer

Check the /etc/resolv.conf on the host

Answer

Restart all nodes in the cluster

Question 3

Which TWO of the following could cause a Node to be in NotReady state?

Accepted Answer

The kubelet process has stopped. A Node is NotReady if the kubelet is not reporting healthy. Common causes include kubelet failure and network plugin issues.

Answer

The node has a taint that prevents scheduling

Answer

The node has insufficient disk space

Answer

The node's IP address has changed

Question 4

A node in your cluster is marked as NotReady. You SSH into the node and run 'systemctl status kubelet'. The output shows the kubelet is inactive (dead). What should you do FIRST to restore the node?

Accepted Answer

Run 'systemctl start kubelet'. The kubelet service is stopped. The first step is to start it with 'systemctl start kubelet'. If it fails to start, further investigation with journalctl is needed.

Answer

Reboot the node

Answer

Delete the node object from the cluster

Answer

Reinstall the kubelet package

Question 5

Which command can you use to view the logs of a container that has crashed and been restarted?

Accepted Answer

kubectl logs pod-name --previous. The --previous flag retrieves logs from the previous instance of the container.

Answer

kubectl describe pod pod-name

Answer

kubectl exec pod-name -- cat /var/log/crash.log

Answer

kubectl logs pod-name

Question 6

A Deployment named 'web' is failing to schedule pods. You run 'kubectl describe pod web-xyz' and see the event: '0/3 nodes are available: 3 Insufficient cpu.' What is the most likely cause?

Accepted Answer

The CPU request in the pod spec is too high. The error indicates that CPU requests are too high for the available node resources. Reducing CPU requests or adding more nodes can fix it.

Answer

The network plugin is misconfigured

Answer

The nodes have insufficient memory

Answer

The kubelet is not running on the nodes

Question 7

You deploy a pod with image 'nginx:1.21'. It stays in ImagePullBackOff. You run 'kubectl describe pod nginx-pod' and see the event: 'Failed to pull image "nginx:1.21": rpc error: code = Unknown desc = Error response from daemon: manifest for nginx:1.21 not found'. What is the most likely fix?

Accepted Answer

Change the image tag to a valid one, e.g., nginx:1.21.6. The tag '1.21' does not exist in the registry. Use a valid tag like '1.21.6' or 'latest'.

Answer

Use a different container runtime

Answer

Add imagePullSecrets to the pod

Answer

Restart the kubelet on the node

Question 8

Which command shows resource usage (CPU and memory) for nodes in a cluster?

Accepted Answer

kubectl top nodes. kubectl top nodes displays resource usage if metrics-server is installed.

Answer

kubectl describe nodes

Answer

kubectl logs nodes

Answer

kubectl get nodes -o wide

Question 9

You cannot reach a service by its DNS name from within a pod. Running 'kubectl exec -it dnsutils -- nslookup myservice' returns 'server can't find myservice: NXDOMAIN'. Which of the following is the MOST probable cause?

Accepted Answer

The service is in a different namespace and you are not using the fully qualified name. The service exists but DNS resolution fails, often because the service is in a different namespace and the DNS query uses only the bare name.

Answer

The pod's resolv.conf is missing the cluster domain

Answer

CoreDNS is configured with a custom upstream DNS server

Answer

The kube-dns pod is not running

Question 10

The controller-manager logs show repeated errors: 'Failed to list *v1.Pod: connection refused'. What is the most likely cause?

Accepted Answer

The API server is down or not reachable. The controller-manager communicates with the API server. 'connection refused' indicates the API server is not reachable or not running.

Answer

The kube-controller-manager is not running

Answer

The kubelet on the controller node is down

Answer

The scheduler is overloading the API server

Question 11

A pod is in CrashLoopBackOff. You run 'kubectl logs pod-name' and see nothing. You suspect the app is failing due to a missing environment variable. Which command can you use to verify environment variables inside the container?

Accepted Answer

kubectl exec pod-name -- env. kubectl exec allows running commands inside a container. 'env' will list environment variables.

Answer

kubectl get pod pod-name -o yaml

Answer

kubectl logs pod-name --previous

Answer

kubectl describe pod pod-name

Question 12

Which command would you use to view all events in the cluster sorted by timestamp?

Accepted Answer

kubectl get events. `kubectl get events` retrieves all cluster events, which are Kubernetes API objects that record state changes and errors. By default, events are sorted by their `lastTimestamp` field, making this the direct command to view events ordered by timestamp.

Answer

kubectl top events

Answer

kubectl logs --events

Answer

kubectl describe events

Question 13

A pod is in ImagePullBackOff. Which TWO of the following are possible causes? (Select 2)

Accepted Answer

The image is in a private registry and no imagePullSecrets are defined. Common causes: invalid image tag (typo) and authentication failure when the image is in a private registry.

Answer

The node has insufficient memory

Answer

The pod has a resource limit that is too low

Answer

The kubelet is not running

Question 14

A pod is stuck in Pending state. Which TWO of the following could be causes? (Select 2)

Accepted Answer

The pod requires a PersistentVolumeClaim that is not bound. Pending pods often lack resources or have unscheduled taints. PVC binding is also a common cause.

Answer

The pod's container image is invalid

Answer

The kube-apiserver is down

Answer

The pod has a taint that no node tolerates

Question 15

Which THREE of the following are valid commands to troubleshoot network connectivity between pods? (Select 3)

Accepted Answer

kubectl exec pod-a -- nslookup service-name. kubectl exec can run networking tools inside a pod. curl is a common tool. nslookup tests DNS. ping tests basic connectivity.

Answer

kubectl describe node | grep Network

Answer

kubectl logs pod-a | grep network