CKAD Application Observability and Maintenance Practice Test 4 — 15 Questions

Question 1

You want to run a command inside a running container to check environment variables. Which command should you use?

Accepted Answer

kubectl exec pod-name -- env. `kubectl exec pod-name -- env` runs the `env` command inside the specified container, which prints all environment variables set in the container's runtime environment. This is the most direct and efficient way to inspect environment variables without entering an interactive shell.

Answer

kubectl logs pod-name

Answer

kubectl describe pod pod-name

Answer

kubectl exec -it pod-name -- /bin/bash

Question 2

What is the purpose of the 'kubectl describe pod' command?

Accepted Answer

Display detailed information about a pod, including recent events. The 'kubectl describe pod' command retrieves detailed metadata about a specific pod, including its current state, labels, annotations, container specifications, volumes, and a chronological list of recent events (e.g., image pull failures, container restarts, scheduling decisions). This aggregated information is essential for debugging pod lifecycle issues because it surfaces both static configuration and dynamic cluster-level events that are not shown in the pod's YAML manifest or logs.

Answer

Execute a command inside a pod

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Display resource usage of a pod

Answer

Show the logs of a pod

Question 3

A pod named 'web' is in a CrashLoopBackOff state. You suspect the application is failing due to a configuration error. You want to see the logs from the previous instance of the container. Which command should you use?

Accepted Answer

kubectl logs web --previous. The `--previous` flag in `kubectl logs` retrieves logs from the previous instance of a container in a pod that has restarted. Since the pod is in CrashLoopBackOff, the current container has likely crashed and a new one has started; `--previous` shows the logs from the terminated container that caused the crash, helping diagnose the configuration error.

Answer

kubectl logs web

Answer

kubectl logs -f web

Answer

kubectl describe pod web

Question 4

Which command shows the CPU and memory usage of all pods in the current namespace?

Accepted Answer

kubectl top pod. `kubectl top pod` without a specific pod name retrieves CPU and memory usage metrics for all pods in the current namespace, as the command defaults to listing all pods when no pod name is provided. This relies on the metrics-server collecting resource usage data from the kubelet's cAdvisor endpoint via the Resource Metrics API.

Answer

kubectl top node

Answer

kubectl top --all

Answer

kubectl top pod pod-name

Question 5

You have a pod that is in a 'Pending' state. You run 'kubectl describe pod' and see the event: '0/3 nodes are available: 3 Insufficient cpu'. What is the most likely cause?

Accepted Answer

The pod's CPU request is larger than the available CPU on any node. The event '0/3 nodes are available: 3 Insufficient cpu' indicates that the Kubernetes scheduler attempted to place the pod on each of the three nodes but found that none had enough allocatable CPU capacity to satisfy the pod's CPU request. This means the sum of CPU requests across all pods on each node, plus the new pod's request, exceeds the node's CPU capacity. The pod remains in 'Pending' because the scheduler cannot find a suitable node until CPU resources are freed or the request is reduced.

Answer

The pod requires more memory than any node can provide

Answer

The pod's liveness probe is failing

Answer

All nodes are tainted and the pod does not tolerate the taints

Question 6

You need to configure a liveness probe for a container that listens on TCP port 8080. The probe should wait 5 seconds before starting, check every 10 seconds, and timeout after 2 seconds. Which YAML snippet correctly configures this?

Accepted Answer

livenessProbe:
  tcpSocket:
    port: 8080
  initialDelaySeconds: 5
  periodSeconds: 10
  timeoutSeconds: 2. It uses the `tcpSocket` probe type to check TCP port 8080, which is appropriate for a container that listens on TCP. The fields `initialDelaySeconds: 5`, `periodSeconds: 10`, and `timeoutSeconds: 2` match the required timing parameters exactly as specified in the Kubernetes API.

Answer

livenessProbe:
  exec:
    command:
    - echo
    - ok
  initialDelaySeconds: 5
  periodSeconds: 10
  timeoutSeconds: 2

Answer

livenessProbe:
  tcpSocket:
    port: 8080
  initialDelay: 5
  period: 10
  timeout: 2

Answer

livenessProbe:
  httpGet:
    path: /
    port: 8080
  initialDelaySeconds: 5
  periodSeconds: 10
  timeoutSeconds: 2

Question 7

You are troubleshooting a service connectivity issue. You have a pod named 'client' and a service named 'server'. You want to check if the service's endpoints are populated. Which command should you run?

Accepted Answer

kubectl get endpoints server. `kubectl get endpoints server` directly retrieves the Endpoints object associated with the service named 'server'. Endpoints are automatically managed by Kubernetes and list the IP addresses and ports of pods that match the service's selector. If the endpoints list is empty, it indicates that no pods are matching the service's selector, which is a common cause of connectivity issues.

Answer

kubectl describe pod client

Answer

kubectl get pods -l app=server

Answer

kubectl get svc server

Question 8

Which TWO of the following are valid types of probes in Kubernetes? (Select 2)

Accepted Answer

Readiness probe. A is correct because a Readiness probe determines whether a Pod is ready to serve traffic. If the probe fails, the Pod is removed from the Service's endpoints, preventing traffic from being routed to an unready container. This is essential for rolling updates and graceful shutdowns.

Answer

HTTP probe

Answer

Exec probe

Answer

TCP probe

Question 9

Which THREE of the following are valid fields for configuring a probe in Kubernetes? (Select 3)

Accepted Answer

initialDelaySeconds. `initialDelaySeconds` is a valid field in a Kubernetes probe configuration (e.g., livenessProbe, readinessProbe, startupProbe). It defines the number of seconds after the container has started before the probe is initiated, allowing the application time to initialize before health checks begin.

Answer

retrySeconds

Answer

intervalSeconds

Question 10

Which TWO of the following are valid reasons to use a readiness probe? (Select 2)

Accepted Answer

To prevent traffic from being sent to a pod that is not ready due to a dependency. A readiness probe is used to determine whether a pod is ready to serve traffic. Option A is correct because it prevents traffic from being sent to a pod that is not ready due to a dependency, such as a database or cache that hasn't fully initialized. The kubelet uses the probe's success or failure to control whether the pod's IP address is added to the endpoints of a Service, ensuring only ready pods receive requests.

Answer

To monitor resource usage and scale the pod

Answer

To delay the start of the application until a database is available

Answer

To restart the container if it becomes unresponsive

Question 11

Which THREE of the following are correct statements about the terminationGracePeriodSeconds field? (Select 3)

Accepted Answer

The default value is 30 seconds. The Kubernetes documentation specifies that the default value for terminationGracePeriodSeconds is 30 seconds. This field is part of the PodSpec and controls the duration between sending SIGTERM to the container and forcefully killing it with SIGKILL. If not set, Kubernetes applies this default to ensure a reasonable window for graceful shutdown.

Answer

The default value is 0 seconds

Answer

It is used to configure the readiness probe timeout

Question 12

Which TWO of the following are valid approaches to debug a pod that is in a CrashLoopBackOff state? (Select 2)

Accepted Answer

Use 'kubectl debug' to start an ephemeral container for troubleshooting. 'kubectl debug' can start an ephemeral container in the same pod as the crashing container, allowing you to inspect the environment (e.g., filesystem, network, processes) without the main container running. This is especially useful when the main container crashes immediately and you cannot exec into it. Ephemeral containers share the pod's namespaces (e.g., network, PID) and can mount the same volumes, giving you a live debugging environment.

Answer

Exec into the pod with 'kubectl exec -it' to inspect the environment

Answer

Check resource usage with 'kubectl top pod'

Answer

Create a new pod with 'kubectl run' using the same image

Question 13

You need to view the logs of a container named 'sidecar' inside a pod named 'app'. Which command should you use?

Accepted Answer

kubectl logs app -c sidecar. `kubectl logs app -c sidecar` explicitly targets the 'sidecar' container within the 'app' pod. In Kubernetes, when a pod runs multiple containers, you must use the `-c` flag to specify which container's logs to retrieve; otherwise, the command fails or returns ambiguous output.

Answer

kubectl logs app --previous -c sidecar

Answer

kubectl logs app sidecar

Answer

kubectl logs app -c sidecar -p

Question 14

You have a Deployment with a liveness probe using an exec command. The probe currently runs 'cat /tmp/healthy' and fails after 3 failures. You notice the pod is being restarted even though the application is healthy. What is the most likely cause?

Accepted Answer

The file /tmp/healthy does not exist or is not being updated by the application. The liveness probe executes 'cat /tmp/healthy' and fails after 3 consecutive failures. If the file /tmp/healthy does not exist or is not being updated by the application, the command returns a non-zero exit code, causing the probe to fail and Kubernetes to restart the container even though the application process itself is running and healthy.

Answer

The readiness probe is misconfigured and is shutting down the pod

Answer

The liveness probe is using the wrong HTTP endpoint

Answer

The probe timeoutSeconds is set too low, causing the probe to fail before the command completes

Question 15

You want to debug a pod that is not responding. You need to run an interactive shell inside a running container. Which command should you use?

Accepted Answer

kubectl exec -it -- /bin/bash. `kubectl exec -it -- /bin/bash` attaches an interactive terminal session to an already-running container within the specified pod. The `-it` flags combine `--stdin` (keep STDIN open) and `--tty` (allocate a pseudo-TTY), which are required for an interactive shell. This is the standard command for debugging a running pod without creating a new container.

Answer

kubectl run -it <pod> --image=busybox -- /bin/sh

Answer

kubectl exec -i <pod> -- /bin/bash

Answer

kubectl debug -it <pod> --image=busybox -- /bin/sh