CKAD Application Observability and Maintenance Practice Test 6 — 15 Questions

Question 1

You run 'kubectl get pods -o wide' and see that a pod's NODE column shows 'node-1'. You want to see more details about that node's resource usage. Which command should you use?

Accepted Answer

kubectl top node node-1. `kubectl top node node-1` directly displays real-time resource usage (CPU and memory) for the specified node, which is exactly what you need when you want to see more details about a node's resource consumption after identifying the node from `kubectl get pods -o wide`.

Answer

kubectl top pods --all-namespaces

Answer

kubectl describe node node-1

Answer

kubectl top pod node-1

Question 2

A container in your pod takes a long time to start (up to 5 minutes). You want to avoid the container being restarted by the liveness probe during this period. What should you configure?

Accepted Answer

Add a startup probe with a longer failure threshold. A startup probe is designed specifically for slow-starting containers. It runs at initialization and defers the liveness and readiness probes until it succeeds. By setting a high `failureThreshold` (e.g., 30) with a short `periodSeconds` (e.g., 10s), you allow up to 5 minutes for the container to start without the liveness probe killing it.

Answer

Set a long 'initialDelaySeconds' on the liveness probe

Answer

Add a readiness probe

Answer

Increase the failureThreshold on the liveness probe

Question 3

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 4

You need to debug a pod that has no running containers because it is in a CrashLoopBackOff state. You want to start an ephemeral container with debugging tools in the same namespace. Which command accomplishes this?

Accepted Answer

kubectl debug -it pod-name --image=busybox --target=container-name. `kubectl debug` allows you to start an ephemeral container in an existing pod that is in a CrashLoopBackOff state. The `--target` flag attaches the ephemeral container to the same Linux namespace as the specified container, enabling debugging without restarting the pod. This is the only command that works when the pod has no running containers and `kubectl exec` fails.

Answer

kubectl run debug --image=busybox -it --restart=Never

Answer

kubectl attach pod-name

Answer

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

Question 5

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

Answer

Display resource usage of a pod

Answer

Show the logs of a pod

Question 6

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 7

You have a Deployment that uses a ConfigMap. You update the ConfigMap, but the pods are not picking up the changes. What is the MOST efficient way to force the pods to use the new ConfigMap values without downtime?

Accepted Answer

Run 'kubectl rollout restart deployment/deployment-name'. A is correct because `kubectl rollout restart deployment/deployment-name` triggers a new ReplicaSet and gracefully terminates old pods while creating new ones, which will mount the updated ConfigMap. This avoids downtime by leveraging the Deployment's rolling update strategy, ensuring the new pods read the current ConfigMap data from the volume mount or environment variable reference.

Answer

Delete the pods manually and let the ReplicaSet recreate them

Answer

Delete the ConfigMap and recreate it with the same name

Answer

Edit the Deployment to add an annotation, triggering a rollout

Question 8

You want to ensure your application shuts down gracefully when a pod is terminated. The application needs 30 seconds to clean up. Which field should you set in the pod spec?

Accepted Answer

terminationGracePeriodSeconds: 30. `terminationGracePeriodSeconds` defines the time Kubernetes waits for a pod to shut down gracefully after sending a SIGTERM signal. Setting it to 30 seconds gives the application the required cleanup window before a SIGKILL is forced.

Answer

spec.containers[].livenessProbe.initialDelaySeconds: 30

Answer

spec.containers[].lifecycle.preStop.exec.command: ["sleep", "30"]

Answer

spec.containers[].readinessProbe.periodSeconds: 30

Question 9

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 10

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 11

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 12

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 13

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 14

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 15

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