CKAD Application Observability and Maintenance Practice Test 10 — 15 Questions

Question 1

A pod uses a liveness probe with exec command 'cat /tmp/healthy'. The file /tmp/healthy exists initially but is deleted by the application after 60 seconds. Which behavior will occur?

Accepted Answer

The liveness probe will fail and the container will be restarted. The liveness probe in Kubernetes periodically checks the health of a container by executing the specified command. When the file /tmp/healthy is deleted, the 'cat /tmp/healthy' command fails (returns non-zero exit code), causing the liveness probe to fail. After consecutive failures (default threshold is 3), kubelet restarts the container to attempt recovery, which is the expected behavior for a failing liveness probe.

Answer

The pod will continue running because the liveness probe only checks at startup

Answer

The pod will be deleted and recreated by the Deployment

Answer

The pod will be marked as NotReady and removed from the Service

Question 2

You need to view the logs of a container that previously crashed and has been restarted. Which flag do you use with 'kubectl logs'?

Accepted Answer

--previous. The `--previous` flag is used with `kubectl logs` to view logs from the previous instance of a container that has crashed and been restarted. This allows you to inspect the logs of the terminated container before the restart, which is essential for debugging crash loops.

Answer

--all-containers

Answer

--tail

Answer

-f

Question 3

A pod has a readiness probe using tcpSocket on port 3306. The application listens on port 3306 but returns errors on database queries. What is the effect of the readiness probe?

Accepted Answer

The pod will be considered ready as long as the TCP port is open, even if the application is not fully functional. A readiness probe with tcpSocket only checks whether the TCP port is open and accepting connections. It does not verify application-level health, such as whether the application can process queries or return valid responses. Since port 3306 is open, the probe succeeds, and the pod is considered ready, even though the application returns errors on database queries.

Answer

The pod will be evicted from the node

Answer

The pod will be marked not ready because the application returns errors

Answer

The container will be restarted due to readiness probe failure

Question 4

Which command outputs the pod's full YAML specification including status?

Accepted Answer

kubectl get pod -o yaml. `kubectl get pod -o yaml` outputs the full YAML specification of the pod, including its status (e.g., conditions, container statuses, phase). The `-o yaml` flag retrieves the complete Kubernetes resource object from the API server, which includes both the desired spec and the current status, as stored in etcd.

Answer

kubectl describe pod <pod-name>

Answer

kubectl get pod <pod-name> --export

Answer

kubectl get pod <pod-name> -o json

Question 5

Which THREE of the following are valid types of probes in Kubernetes? (Select 3)

Accepted Answer

Liveness probe. Liveness, Readiness, and Startup probes are all valid probe types in Kubernetes. Liveness probes check if a container is still running and can restart it if needed. Readiness probes determine if a container is ready to serve traffic. Startup probes delay liveness and readiness checks until the container has started successfully. Options B (Survival) and D (Health) are not valid Kubernetes probe types.

Answer

Survival probe

Answer

Health probe

Question 6

Which THREE of the following are valid parameters for configuring probes? (Select 3)

Accepted Answer

timeoutSeconds. In Kubernetes, probe configuration parameters are defined in the container spec within a Pod. `timeoutSeconds` is a valid parameter that specifies the number of seconds after which the probe times out, defaulting to 1 second if not set. It is used in liveness, readiness, and startup probes to control how long kubelet waits for a probe response before considering it failed.

Answer

retryIntervalSeconds

Answer

cooldownSeconds

Question 7

Which THREE of the following are true about the 'kubectl describe pod' output? (Select 3)

Accepted Answer

It shows the exact resource requests and limits of each container. kubectl describe pod provides static configuration details and recent events. It shows resource requests and limits per container (A), recent pod events (C), and the node name where the pod is scheduled (E). It does not show container logs (B) or current CPU/memory usage (D).

Answer

It shows the last few lines of the container logs

Answer

It shows the current CPU and memory usage of the pod

Question 8

Which kubectl command can you use to stream the logs from a pod in real-time?

Accepted Answer

kubectl logs -f. The `-f` flag (short for `--follow`) in `kubectl logs` streams the log output in real-time, similar to `tail -f` on a Linux system. This allows you to observe new log entries as they are written by the pod's containers, which is essential for debugging live issues or monitoring application behavior.

Answer

kubectl logs --previous

Answer

kubectl logs

Answer

kubectl logs --tail=10

Question 9

You need to configure a liveness probe for a container that starts a web server on port 8080. The probe should check the '/healthz' endpoint. Which YAML snippet correctly defines this probe?

Accepted Answer

livenessProbe:
  httpGet:
    path: /healthz
    port: 8080. It defines an HTTP GET liveness probe that checks the '/healthz' endpoint on port 8080, which is the standard way to verify the health of a web server. The `httpGet` probe sends an HTTP GET request to the specified path and port, and the container is considered healthy if the response status code is between 200 and 399.

Answer

livenessProbe:
  exec:
    command: ["curl", "http://localhost:8080/healthz"]

Answer

livenessProbe:
  httpGet:
    port: 8080

Answer

livenessProbe:
  tcpSocket:
    port: 8080

Question 10

A pod is running but not receiving traffic from a Service. The readiness probe is failing. What is the likely effect on the pod?

Accepted Answer

The pod will remain running but will not be included in the Service's endpoints. When a readiness probe fails, Kubernetes marks the pod as not ready. The pod continues running, but the associated Service removes the pod's IP from its Endpoints (or EndpointSlice) list. This ensures the Service does not route traffic to a pod that is not prepared to handle requests, while allowing the pod to remain alive for debugging or other internal operations.

Answer

The pod will be marked as CrashLoopBackOff

Answer

The pod will be terminated and restarted

Answer

The pod will be evicted from the node

Question 11

You have a pod that takes 2 minutes to start its application. You want to avoid the liveness probe from killing the pod during startup, but still have it active afterward. Which probe should you add to the pod spec?

Accepted Answer

Add a startup probe with a failureThreshold high enough to cover the startup time. A startup probe is designed specifically for slow-starting containers. It runs before the liveness probe and, if it fails, the container is killed. By setting a high failureThreshold (e.g., 12 with a 10-second period gives 120 seconds), you allow the application up to 2 minutes to start without the liveness probe interfering. Once the startup probe succeeds, the liveness probe takes over normally.

Answer

Increase the timeoutSeconds on the liveness probe

Answer

Set periodSeconds on the liveness probe to 120

Answer

Set initialDelaySeconds on the liveness probe to 120

Question 12

You want to see detailed information about a node's resource usage. Which command should you run?

Accepted Answer

kubectl top node. `kubectl top node` retrieves real-time CPU and memory usage metrics for nodes from the metrics server, which is essential for monitoring resource consumption. This command directly answers the question about detailed resource usage, unlike other options that provide configuration or log data.

Answer

kubectl describe node

Answer

kubectl logs node

Answer

kubectl get nodes -o wide

Question 13

Which field in the container spec controls the time Kubernetes waits after sending SIGTERM before sending SIGKILL during pod shutdown?

Accepted Answer

terminationGracePeriodSeconds. `terminationGracePeriodSeconds` is the field in the Pod spec that defines the duration Kubernetes waits after sending SIGTERM to the main process in each container before forcefully sending SIGKILL. This grace period allows the application to perform clean shutdown tasks, such as closing connections or flushing data. The default value is 30 seconds if not specified.

Answer

timeoutSeconds

Answer

periodSeconds

Answer

activeDeadlineSeconds

Question 14

You have a Deployment with a liveness probe that fails intermittently, causing the pod to restart. You want to reduce the sensitivity of the probe so that it only restarts after 3 consecutive failures. Which probe parameter should you adjust?

Accepted Answer

failureThreshold. The `failureThreshold` parameter defines the number of consecutive probe failures required before Kubernetes considers the probe to have failed and triggers the configured action (e.g., restarting the container). By default, this value is 3, but if it is set lower (e.g., 1), a single failure causes a restart. Increasing `failureThreshold` to 3 (or higher) ensures that the liveness probe only restarts the pod after three consecutive failures, thereby reducing sensitivity to transient issues.

Answer

initialDelaySeconds

Answer

periodSeconds

Answer

successThreshold

Question 15

You run 'kubectl get pods' and see that a pod is in 'Pending' state. What is the most likely cause?

Accepted Answer

The node has insufficient resources to run the pod. A pod in 'Pending' state indicates that the pod has been accepted by the Kubernetes API server but is not yet scheduled to a node. The most common cause is insufficient resources (CPU, memory, or ephemeral storage) on any available node, which prevents the scheduler from binding the pod. This is confirmed by running 'kubectl describe pod <pod-name>' and checking the 'Events' section for messages like '0/1 nodes are available: Insufficient cpu'.

Answer

The readiness probe is failing

Answer

The container command exited with an error

Answer

The pod's imagePullPolicy is set to Never