CKA Practice Test 5 — 10 Questions

Question 1

A Kubernetes cluster has been running for months. Recently, some pods are reporting 'FailedScheduling' due to insufficient memory. The administrator wants to add a new node with 32GB RAM. However, after joining the node, the new node shows 'NotReady' and the kubelet logs indicate 'Failed to update node status: context deadline exceeded'. What is the most likely cause?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

There is a network connectivity issue between the new node and the control plane.. The 'context deadline exceeded' error in the kubelet logs indicates that the kubelet on the new node is unable to communicate with the API server within the expected timeout. This is typically caused by network connectivity issues between the node and the control plane, such as firewall rules, incorrect DNS resolution, or a broken CNI plugin. Without successful node-to-API-server communication, the kubelet cannot post its status, leaving the node in 'NotReady' state.

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The kubelet is not configured with the correct node IP.

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The new node does not have enough disk space for container images.

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The API server is overloaded and cannot handle the node update request.

Question 2

A user reports that a pod is stuck in 'ContainerCreating' state. Which command would you run first to diagnose the issue?

Accepted Answer

kubectl describe pod <pod-name>. The 'ContainerCreating' state indicates the pod has been scheduled but the container runtime is failing to start the container. `kubectl describe pod` provides detailed events, status conditions, and error messages from the kubelet, such as image pull failures, volume mount errors, or CNI plugin issues, which are the most direct source of diagnostic information for this state.

Answer

kubectl logs <pod-name>

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kubectl get events --watch

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kubectl exec -it <pod-name> -- /bin/sh

Question 3

An administrator runs 'kubectl cordon node1' and then 'kubectl drain node1 --ignore-daemonsets'. What is the effect on node1?

Accepted Answer

Node1 is marked as unschedulable and all pods except DaemonSets are evicted. The `kubectl cordon node1` command marks node1 as unschedulable, preventing new pods from being scheduled onto it. The subsequent `kubectl drain node1 --ignore-daemonsets` command evicts all pods from node1 except DaemonSets (which are ignored because they are managed by the DaemonSet controller and typically need to run on every node). This combination makes node1 unschedulable and removes all non-DaemonSet pods, preparing the node for maintenance.

Answer

Node1 is marked as unschedulable but no pods are evicted

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New pods are scheduled onto node1 and existing pods are evicted

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Node1 is marked as schedulable and all pods are evicted

Question 4

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

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The kubelet on the controller node is down

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The scheduler is overloading the API server

Question 5

You run 'kubectl get events --sort-by='.lastTimestamp'' and see repeated events: 'Failed to pull image "myimage:v2": rpc error: code = Unknown desc = Error response from daemon: manifest for myimage:v2 not found'. What is the issue?

Accepted Answer

The image tag 'myimage:v2' does not exist in the registry.. The error 'manifest not found' means the image tag does not exist in the registry. The pod is in ImagePullBackOff because the image is missing.

Answer

The pod has insufficient privileges to pull the image.

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The image registry is down.

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The container runtime is not running.

Question 6

Which command shows resource usage for pods and nodes in the cluster?

Accepted Answer

kubectl top pods and kubectl top nodes. The metrics server must be installed. 'kubectl top pods' shows pod CPU/memory usage, and 'kubectl top nodes' shows node usage.

Answer

kubectl cluster-info

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kubectl get --sort-by=.status.capacity

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kubectl describe pods and kubectl describe nodes

Question 7

You run 'kubectl get pods -n default' and see a pod named 'backend' in ImagePullBackOff state. What is the most likely cause?

Accepted Answer

The image name or tag is incorrect. ImagePullBackOff indicates Kubernetes cannot pull the container image, often due to a tag typo or non-existent image.

Answer

The node is out of disk space

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The container's memory limit is too low

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The pod's service account lacks permissions

Question 8

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

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You do not have permission to view node metrics

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The kubelet is not running on the nodes

Question 9

A Pod is stuck in CrashLoopBackOff. You run `kubectl logs <pod-name>` but see no output. What is the most likely cause?

Accepted Answer

The container crashes before writing to stdout/stderr.. When a container crashes before it can write any output to stdout or stderr, `kubectl logs` returns no output because there is no log data to retrieve. This is a common symptom of a container that fails during initialization or immediately upon entry point execution, before any logging occurs.

Answer

The pod has no container defined.

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The kubelet is not forwarding logs.

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The pod is in a different namespace.

Question 10

A user creates a Deployment with replicas=3. Two Pods are running, but the third is stuck in ContainerCreating. 'kubectl describe pod' shows 'Failed to create pod sandbox: rpc error: code = Unknown desc = failed to create containerd task: OCI runtime create failed: container_linux.go:349: starting container process caused: exec: "/app": stat /app: no such file or directory'. What is the most likely cause?

Accepted Answer

The container image does not have the /app executable at the specified path.. The error message 'exec: "/app": stat /app: no such file or directory' indicates that the container runtime (containerd) successfully created the sandbox and started the container process, but the command specified in the container's entrypoint or command tried to execute '/app', which does not exist inside the container image. This is a classic misconfiguration where the image lacks the expected binary or script at the given path, causing the container to fail immediately after creation.

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The container image is not pulled due to authentication failure.

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The container exceeds its memory limit and is killed.

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The node is not schedulable due to taints.