CKA Troubleshooting Practice Test 16 — 15 Questions

Question 1

You are troubleshooting a node that is 'NotReady'. Which THREE of the following are possible causes? (Choose three.)

Accepted Answer

The kubelet cannot contact the API server. The kubelet is the primary node agent that communicates with the API server to report node status, heartbeats, and pod lifecycle events. If the kubelet cannot reach the API server (e.g., due to network partition, TLS certificate issues, or API server downtime), it cannot send the periodic NodeStatus updates, and the control plane marks the node as 'NotReady' after the `node-monitor-grace-period` (default 40 seconds) expires.

Answer

The node has disk pressure

Answer

A pod on the node is consuming excessive memory

Question 2

Which TWO of the following kubectl commands can be used to view the logs of a container in a pod? (Choose two.)

Accepted Answer

kubectl logs pod-name. Option B, `kubectl logs pod-name`, is correct because the `kubectl logs` command is the dedicated subcommand for retrieving the stdout/stderr output of a container in a pod, and with a single container it defaults to that container. Option E, `kubectl logs pod-name --previous`, is also correct because the `--previous` (or `-p`) flag retrieves the logs from the previous, terminated instance of the container in the pod, which is still a valid way to view container logs. Option A, `kubectl describe pod pod-name`, is not correct because describe shows pod metadata, events, and status, not the container's log stream. Option C, `kubectl exec pod-name -- logs`, is not correct because it attempts to run a `logs` binary inside the container rather than using the Kubernetes logs API. Option D, `kubectl get pod pod-name -o yaml`, is not correct because it only outputs the pod's YAML manifest/status, not its container logs.

Answer

kubectl describe pod pod-name

Answer

kubectl exec pod-name -- logs

Answer

kubectl get pod pod-name -o yaml

Question 3

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 4

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

Answer

The container's memory limit is too low

Answer

The pod's service account lacks permissions

Question 5

Which command shows the logs of a pod that has crashed and restarted?

Accepted Answer

kubectl logs pod-name --previous. kubectl logs --previous shows logs from the previous container instance.

Answer

kubectl logs pod-name

Answer

kubectl logs pod-name -c container-name

Answer

kubectl describe pod pod-name

Question 6

You run 'kubectl get nodes' and one node shows 'NotReady'. You SSH into the node and run 'systemctl status kubelet'. Kubelet is active but 'journalctl -u kubelet -n 50' shows 'network plugin is not ready: cni config uninitialized'. What is the most likely cause?

Accepted Answer

The CNI configuration file is missing or incorrect. The CNI plugin configuration is missing, causing the network plugin to be unready.

Answer

The container runtime is not installed

Answer

Kubelet is not running

Answer

The node's IP address has changed

Question 7

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

Accepted Answer

The Metrics Server is not deployed. Metrics server is not deployed or not ready, so resource metrics are unavailable.

Answer

kubectl top requires root access

Answer

Nodes have insufficient CPU

Answer

Kubelet is not running on nodes

Question 8

Which command shows events sorted by timestamp for troubleshooting recent issues?

Accepted Answer

kubectl get events --sort-by=.lastTimestamp. The correct option is B, `kubectl get events --sort-by=.lastTimestamp`, because `kubectl get events` lists cluster events and the `--sort-by=.lastTimestamp` flag sorts them by the time each event last occurred, making it easy to spot the most recent events for troubleshooting. The `.lastTimestamp` field is the exact sortable field on Event objects that reflects when the event was last observed. Option A is invalid because `kubectl logs` retrieves container logs and has no `--events` flag. Option C is invalid because `kubectl describe` operates on a specific resource and does not accept `events` as a resource type in that form. Option D is incomplete: `kubectl get events` lists events but does not sort them by timestamp, so recent issues may not appear first.

Answer

kubectl logs --events

Answer

kubectl describe events

Answer

kubectl get events

Question 9

You run 'kubectl get pods' and see a pod named 'db' in CrashLoopBackOff. 'kubectl logs db' shows nothing. 'kubectl logs db --previous' shows 'Error: database connection failed'. What is the most likely cause?

Accepted Answer

The environment variable for database host is incorrect. The 'kubectl logs db --previous' output shows 'Error: database connection failed', which indicates the application inside the container is failing to connect to a database. Since the current logs are empty (the container restarted), the previous logs reveal the root cause: a configuration issue, most likely an incorrect database host environment variable. This is a classic application-level startup failure, not a resource or probe issue.

Answer

The node is out of memory

Answer

The pod's liveness probe is misconfigured

Answer

The container image is missing

Question 10

A pod is stuck in Pending state. 'kubectl describe pod' shows '0/1 nodes are available: 1 node(s) had taint {key=value: NoSchedule}, 1 node(s) had taint {node.kubernetes.io/unreachable: }. What does this indicate?

Accepted Answer

The pod does not tolerate the taints on the available nodes. The pod cannot tolerate the taints. One node has a custom taint, another is unreachable.

Answer

The nodes are all in NotReady state

Answer

The pod requires at least 2 nodes

Answer

The pod has insufficient resources

Question 11

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 12

A pod is in CrashLoopBackOff. 'kubectl logs my-pod --previous' shows: 'Error: failed to start: exec: "/app/start.sh": stat /app/start.sh: no such file or directory'. What is the most likely cause?

Accepted Answer

The container image is missing the startup script.. The error indicates the specified entrypoint script is missing. This is often due to the container image not containing the script at the expected path, or the command/args in the pod spec referencing a non-existent file.

Answer

The pod's service account lacks permissions.

Answer

The pod's liveness probe is misconfigured.

Answer

The pod has run out of memory.

Question 13

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.

Answer

The image registry is down.

Answer

The container runtime is not running.

Question 14

A pod is stuck in 'Pending' state. You run 'kubectl describe pod mypod' and see: '0/4 nodes are available: 4 node(s) didn't match pod anti-affinity constraints'. What does this mean?

Accepted Answer

The pod's anti-affinity rule conflicts with all existing pods on every node.. The error message '4 node(s) didn't match pod anti-affinity constraints' directly indicates that the pod's anti-affinity rule (defined in the pod spec under `affinity.podAntiAffinity`) prevents it from being scheduled on any node because the rule conflicts with the labels of existing pods on all nodes. Anti-affinity ensures the pod is not co-located with certain pods, and if every node already hosts a pod matching the anti-affinity selector, no node is eligible. This is distinct from taints, node selectors, or resource shortages.

Answer

The pod has a taint that no node tolerates.

Answer

The pod has a node selector that doesn't match any node.

Answer

The cluster is out of resources.

Question 15

You run 'kubectl top nodes' and it returns an error: 'error: metrics not available yet'. What does this indicate?

Accepted Answer

The Metrics Server is not installed or not functioning.. The 'top' command relies on the metrics server to provide resource usage data. The error means the metrics server is not deployed or not ready.

Answer

The kubelet is not running on the nodes.

Answer

The cluster is using an older version of Kubernetes.

Answer

The nodes are under heavy load.