CKA Troubleshooting Practice Test 10 — 15 Questions

Question 1

You deploy a pod with the following YAML and it remains in 'Pending' state. What is the most likely cause?

```yaml
apiVersion: v1
kind: Pod
metadata:
  name: myapp
spec:
  containers:
  - name: myapp
    image: nginx
  resources:
    requests:
      memory: "64Gi"
```

Accepted Answer

The pod requests more memory than any node can allocate.. The pod requests 64Gi of memory, which is an extremely high amount that likely exceeds the allocatable memory of any node in the cluster. The Kubernetes scheduler cannot find a node with sufficient resources to satisfy the request, so the pod remains in 'Pending' state. This is a classic resource insufficiency scenario where the scheduler's predicates fail due to insufficient memory.

Answer

The pod is missing a required label.

Answer

The pod has a taint that no toleration matches.

Answer

The image 'nginx' does not exist.

Question 2

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 3

You run 'kubectl get pods' and see that a pod named 'web' is in 'ImagePullBackOff' state. Which command would help you see the reason for the image pull failure?

Accepted Answer

kubectl describe pod web. C is correct because 'kubectl describe pod web' is the standard, most comprehensive command to inspect pod details and lifecycle events. To prevent Option A from being a technically correct alternative, it should be changed to 'kubectl get events web'. Running 'kubectl get events web' is a common mistake; it attempts to find a specific event resource named 'web' rather than filtering events involving the pod 'web', resulting in a 'not found' error.

Answer

kubectl get events --field-selector involvedObject.name=web

Answer

kubectl logs web

Answer

kubectl exec web -- docker pull nginx

Question 4

You have a Deployment that is failing to update. You run 'kubectl rollout status deployment/myapp' and it hangs. Which command should you run to see the status of individual ReplicaSets and pods?

Accepted Answer

kubectl rollout history deployment/myapp. 'kubectl rollout history deployment/myapp' shows the revision history of the Deployment, including the ReplicaSets associated with each revision. This allows you to see the status of individual ReplicaSets and their corresponding pods, which is essential when a rollout hangs because you can identify which ReplicaSet is stuck or failing.

Answer

kubectl describe deployment myapp

Answer

kubectl logs deployment/myapp

Answer

kubectl get replicasets -l app=myapp

Question 5

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 6

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 7

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 8

You deploy a pod with a readiness probe that checks an HTTP endpoint. The probe fails and the pod is marked as 'NotReady'. Which command would you use to see the exact HTTP response from the probe?

Accepted Answer

kubectl describe pod mypod. 'kubectl describe pod' shows the probe details including the specific failure message (e.g., HTTP response code).

Answer

kubectl logs mypod -c mycontainer

Answer

kubectl exec mypod -- curl http://localhost:8080/healthz

Answer

kubectl get pod mypod -o yaml

Question 9

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.

Question 10

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. '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 11

You try to run 'kubectl logs mypod' and get the error: 'Error from server (BadRequest): container "myapp" in pod "mypod" is waiting to start: PodInitializing'. What does this mean?

Accepted Answer

The pod is still being initialized and the container has not started yet.. The error message 'container "myapp" in pod "mypod" is waiting to start: PodInitializing' indicates that the pod's init containers (if any) are still running or the container runtime is pulling the image and setting up the container. The container has not yet entered the 'Running' state, so logs cannot be retrieved until it starts. This is a standard Kubernetes lifecycle phase where the pod is in 'PodInitializing' status, meaning the main container is not ready to serve logs.

Answer

The pod has crashed and is restarting.

Answer

The kubelet is not running on the node.

Answer

The container has a different name than specified.

Question 12

You have a pod that is 'CrashLoopBackOff'. 'kubectl logs --previous mypod' shows: 'Liveness probe failed: HTTP probe failed with statuscode: 503'. Which THREE actions could potentially fix the issue? (Choose three)

Accepted Answer

Increase the initialDelaySeconds to give the app more time to start.. Options B, C, and D are correct. Increasing `initialDelaySeconds` gives the app more time to start before the first probe, preventing premature failure. Changing the probe path to a valid endpoint that returns 200 fixes the 503 error caused by an incorrect endpoint. Increasing `failureThreshold` allows more probe failures before the pod is restarted, accommodating temporary issues. Option E (removing the liveness probe entirely) is not recommended because it removes health checking, allowing the pod to run in an unhealthy state. Option A is incorrect because changing it to a readiness probe does not fix the underlying probe failure, and readiness probes do not trigger container restarts.

Answer

Change the liveness probe to a readiness probe.

Answer

Remove the liveness probe entirely.

Question 13

You run 'kubectl get pods' and see that a pod named 'db' is in 'CrashLoopBackOff'. Which TWO commands are most useful for diagnosing the issue? (Choose two)

Accepted Answer

kubectl describe pod db. 'kubectl describe pod db' provides detailed event logs, status conditions, and recent container restart counts, which directly reveal why the pod is crashing (e.g., OOMKilled, liveness probe failure, or image pull errors). Option C is correct because 'kubectl logs db' retrieves the container's stdout/stderr output, which often contains application-level error messages (e.g., database connection failures or missing config files) that explain the crash loop.

Answer

kubectl top pod db

Answer

kubectl get pod db -o yaml

Answer

kubectl exec db -- /bin/sh

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

You run 'kubectl get nodes' and one node shows 'NotReady'. Which command should you run first to check the kubelet status on that node?

Accepted Answer

journalctl -u kubelet. The kubelet is responsible for node status. On the node, you can check its logs with journalctl.

Answer

kubectl describe node <node-name>

Answer

cat /var/log/syslog | grep kubelet

Answer

systemctl status kube-apiserver