CKA Practice Test 47 — 15 Questions

Question 1

A node in the cluster is showing status 'NotReady'. You run 'kubectl describe node worker1' and see that the kubelet has not posted node status for more than 1 minute. Which command should you run on the node to check the kubelet logs?

Accepted Answer

journalctl -u kubelet. On systemd-based systems, 'journalctl -u kubelet' is the standard command to view kubelet logs. 'journalctl -f -u kubelet' follows the log, but the question asks for checking logs, not following.

Answer

cat /var/log/kubelet/kubelet.log

Answer

kubectl logs kubelet -n kube-system

Answer

systemctl restart kubelet

Question 2

You have a Deployment with three replicas. After a rolling update, all pods are in 'CrashLoopBackOff'. You want to revert to the previous revision. Which command accomplishes this?

Accepted Answer

kubectl rollout undo deployment/myapp. Option C is correct. 'kubectl rollout undo deployment myapp' reverts to the previous revision. Option A is incorrect because --to-revision=1 would roll back to the first revision, not the previous one.

Answer

kubectl rollout undo deployment/myapp --to-revision=1

Answer

kubectl delete deployment/myapp --cascade=foreground

Answer

kubectl rollout status deployment/myapp --revision=2

Question 3

A node is NotReady. Which THREE conditions could cause this?

Accepted Answer

Network plugin (e.g., Calico) is not functioning. Kubelet stopped, network plugin issues, and disk pressure can all cause a node to become NotReady.

Answer

A pod is in CrashLoopBackOff

Answer

The API server is overloaded

Question 4

You need to check the logs of a kubelet on a node. Which command should you run on the node?

Accepted Answer

journalctl -u kubelet. Option A is correct. 'journalctl -u kubelet' is the standard command to view kubelet logs on systemd-based systems. Option B is for Docker daemon. Option C is for kernel messages. Option D is for Apache access logs.

Answer

journalctl -u docker

Answer

dmesg

Answer

tail -f /var/log/apache2/access.log

Question 5

A Deployment has 3 replicas. One pod is in CrashLoopBackOff. You run 'kubectl logs <pod> --previous' and see only a single line: 'Error: failed to start container'. What is the most likely cause?

Accepted Answer

The application crashes immediately due to a misconfiguration. The --previous flag shows logs from the previous container instance. A single line about failing to start container indicates the application exited immediately before the container runtime could capture logs; usually due to a configuration issue that causes a crash on startup.

Answer

The container registry is not accessible

Answer

The container image is missing an entrypoint

Answer

The pod is exceeding its memory limit

Question 6

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 7

You suspect a DNS issue inside a pod. Which command can you run to test DNS resolution from within a pod?

Accepted Answer

kubectl exec <pod-name> -- nslookup kubernetes.default. Option A is correct. Using kubectl exec to run nslookup inside an existing pod tests DNS resolution. Option B is for logs. Option C shows service info. Option D creates a new pod, not using the existing one.

Answer

kubectl logs coredns -n kube-system

Answer

kubectl describe svc kubernetes

Answer

kubectl run test --image=busybox -- nslookup kubernetes.default

Question 8

A pod is stuck in Pending state. You run 'kubectl describe pod my-pod' and see the event: '0/4 nodes are available: 1 node(s) had taint {node.kubernetes.io/not-ready: }, 3 node(s) had taint {node-role.kubernetes.io/control-plane: }, that the pod didn't tolerate'. What is the most likely cause?

Accepted Answer

The pod does not tolerate the control-plane taint. The pod does not tolerate the control-plane taint, so it cannot be scheduled on control-plane nodes. Adding a toleration or removing the taint from a worker node would help.

Answer

The pod has a nodeSelector that doesn't match any node

Answer

The persistent volume claim is not bound

Answer

The pod has a resource request that exceeds available node capacity

Question 9

You run 'kubectl top nodes' and get an error: 'error: metrics not available yet'. What is the most likely cause?

Accepted Answer

The metrics-server is not installed or not running. The metrics server is not deployed or not ready; kubectl top requires the metrics server to collect resource usage data.

Answer

The nodes do not have enough resources to run the metrics collection

Answer

You do not have permission to view node metrics

Answer

The kubelet is not running on the nodes

Question 10

You are troubleshooting a pod that is in 'CrashLoopBackOff' state. You run 'kubectl logs mypod' and get no output. You then run 'kubectl logs mypod --previous' and see an error: 'Error: failed to start container: context deadline exceeded'. What is the MOST likely cause?

Accepted Answer

The container runtime is unable to start the container due to a timeout. Option B is correct. 'context deadline exceeded' indicates that the container runtime timed out while trying to start the container. This is often due to the container image being large and the pull taking too long, or the container runtime being slow. Option A would show a different error. Option C would show an application error in the logs. Option D would show a different error like 'executable file not found'.

Answer

The container image is missing the entrypoint

Answer

The application inside the container is crashing immediately

Answer

The container command is incorrectly specified

Question 11

A pod in the 'production' namespace is in CrashLoopBackOff state. Running 'kubectl describe pod web-app -n production' shows the event 'OOMKilled'. What is the most appropriate action to resolve this issue?

Accepted Answer

Increase the memory limit in the container spec. OOMKilled means the container exceeded its memory limit. Increasing the memory limit is the correct fix.

Answer

Increase the CPU request for the container

Answer

Delete the namespace and redeploy

Answer

Delete and recreate the pod

Question 12

You have a Deployment with 3 replicas. One pod is in CrashLoopBackOff. The other two are Running. You run 'kubectl get events' and see 'Liveness probe failed: HTTP probe failed with statuscode: 503'. What should you do?

Accepted Answer

Check the application health endpoint and fix it to return 200. Liveness probe failure causes container restart. The fix could be adjusting the probe or fixing the app to respond correctly.

Answer

Increase the initialDelaySeconds of the liveness probe

Answer

Scale down the deployment

Answer

Remove the liveness probe

Question 13

A user reports that they cannot access a service running in the cluster from within another pod. They run 'kubectl exec -it pod-a -- curl http://service-b:8080' and get a connection timeout. What is the first thing you should check?

Accepted Answer

Check if the target service's pods have the correct labels.. Since curl from within the pod times out, the issue might be that the service does not have any endpoints (no pods matching the selector). Checking endpoints is a quick way to verify if the service is backed by running pods.

Answer

Check if the service has a ClusterIP assigned.

Answer

Check if the kube-dns pod is running.

Answer

Check if the pod-a has network connectivity by pinging the node IP.

Question 14

A pod is stuck in Pending state. You run 'kubectl describe pod my-pod' and see the event '0/1 nodes are available: 1 Insufficient cpu'. What is the most likely cause?

Accepted Answer

The pod's CPU request exceeds available node CPU. The event indicates that no node has enough free CPU to satisfy the pod's CPU request.

Answer

The pod's memory limit is too low

Answer

The pod is trying to use a GPU that is not available

Answer

The kubelet on the node is not running

Question 15

Which command shows resource usage (CPU/memory) of all pods in the default namespace?

Accepted Answer

kubectl top pods. kubectl top pod shows CPU and memory metrics for pods.

Answer

kubectl describe pods

Answer

kubectl logs pods

Answer

kubectl get pods -o wide