KCNA Kubernetes Fundamentals Practice Test 20 — 15 Questions

Question 1

You run 'kubectl logs my-pod' and see: "Error from server (BadRequest): container "my-container" in pod "my-pod" is waiting to start: PodInitializing". What does this mean?

Accepted Answer

The Pod is in the process of initializing and logs are not yet available. The error 'PodInitializing' indicates that the pod's init containers are still running or the main container is waiting for init containers to complete. During this phase, the container has not started, so logs are not yet available. Option D correctly identifies that the pod is initializing and logs cannot be retrieved until the container enters the 'Running' state.

Answer

The container is running but producing no output

Answer

The container runtime is failing to start the container

Answer

The container has crashed and is restarting

Question 2

You have a Pod that needs to run a one-time batch job to completion. Which resource type should you use?

Accepted Answer

Job. A Job resource is designed for running a finite task to completion, such as a batch job or a one-time computation. Unlike controllers that maintain a desired number of replicas indefinitely, a Job creates one or more Pods and tracks their successful termination. Once the specified number of completions is reached, the Job is considered finished and no further Pods are created.

Answer

StatefulSet

Answer

DaemonSet

Answer

Deployment

Question 3

Which TWO of the following are responsibilities of the kubelet on a worker node?

Accepted Answer

Ensuring containers are running as specified in the PodSpec. Option D is correct because the kubelet is the node agent that watches for PodSpecs assigned to its node and actively reconciles the actual container state to match the desired state, restarting or starting containers via the container runtime (e.g., containerd or CRI-O) so they run as specified. Option E is correct because the kubelet registers its node with the control plane by creating/updating the Node object through the API server, and it periodically reports node status and heartbeats. Option A is wrong because etcd is the cluster's distributed key-value store, written to by the API server, not by the kubelet. Option B is wrong because Pod scheduling is performed by the kube-scheduler, which selects a node and binds the Pod; the kubelet only runs Pods already assigned to it. Option C is wrong because Service network rules (iptables/IPVS or eBPF load-balancing) are implemented by the kube-proxy, not the kubelet.

Answer

Storing cluster state in etcd

Answer

Scheduling Pods onto the node

Answer

Implementing network rules for Services

Question 4

Which TWO of the following are valid ways to expose a Service to external traffic?

Accepted Answer

LoadBalancer. NodePort (D) is correct because it exposes a Service on each cluster node's IP at a static port in the 30000–32767 range, allowing external clients to reach the Service via :. LoadBalancer (C) is correct because it builds on NodePort and provisions an external load balancer (e.g., via a cloud provider) that routes external traffic to the Service's endpoints. ExternalName (A) is not a way to expose a Service to external traffic; it simply returns a CNAME DNS record pointing to an external hostname without proxying traffic. Headless (B) sets clusterIP: None and returns pod IPs directly via DNS, which is used for direct pod discovery, not external exposure. ClusterIP (E) is the default internal-only Service type, reachable only from within the cluster, so it does not expose the Service externally.

Answer

ExternalName

Answer

Headless

Answer

ClusterIP

Question 5

Which Kubernetes control plane component is the primary entry point for all administrative tasks and serves the Kubernetes API?

Accepted Answer

kube-apiserver. The kube-apiserver is the front-end of the Kubernetes control plane and the sole entry point for all administrative operations. It exposes the Kubernetes REST API, validates and processes requests (including authentication, authorization, and admission control), and updates the corresponding objects in etcd. Without the API server, no kubectl command, automation, or internal component communication can occur.

Answer

kube-scheduler

Answer

kube-controller-manager

Answer

etcd

Question 6

Which component runs on every worker node and is responsible for ensuring that containers are running in a pod according to the pod specification?

Accepted Answer

kubelet. The kubelet is the primary node agent that runs on every worker node in a Kubernetes cluster. It registers the node with the API server, watches for PodSpecs assigned to its node, and ensures the containers described in those PodSpecs are running and healthy. It does this by interacting with the container runtime to create, start, and stop containers as needed, and it reports the node and pod status back to the control plane.

Answer

kube-scheduler

Answer

container runtime

Answer

kube-proxy

Question 7

You have a Deployment defined with replicas: 3. You run 'kubectl scale deployment my-deployment --replicas=5'. What happens?

Accepted Answer

The Deployment is updated to have 5 replicas, and the ReplicaSet creates 2 additional pods.. `kubectl scale` directly updates the `.spec.replicas` field of the Deployment, which in turn instructs the existing ReplicaSet to adjust its pod count. The ReplicaSet controller then creates 2 additional Pods to reach the desired 5 replicas, without recreating existing Pods or triggering a rollout.

Answer

The Deployment is updated to have 5 replicas, but existing pods are recreated to match.

Answer

The command fails because you cannot scale a Deployment directly.

Answer

The Deployment rolls out a new version with 5 replicas.

Question 8

A developer needs to update a running Deployment's container image from 'nginx:1.21' to 'nginx:1.23' with minimal downtime and the ability to roll back if the new version fails. Which kubectl command should be used?

Accepted Answer

kubectl set image deployment/my-deployment nginx=nginx:1.23. `kubectl set image` directly updates the container image of a running Deployment, triggering a rolling update that replaces pods gradually to minimize downtime. This command also preserves the Deployment's rollout history, enabling a simple `kubectl rollout undo` to roll back if the new image fails.

Answer

kubectl edit deployment my-deployment

Answer

kubectl apply -f updated-deployment.yaml

Answer

kubectl patch deployment my-deployment -p '{"spec":{"template":{"spec":{"containers":[{"name":"nginx","image":"nginx:1.23"}]}}}}'

Question 9

You want to expose a set of pods running a web application on port 80 internally within the cluster, with a stable IP address, so that other services can reach them. Which Kubernetes resource should you create?

Accepted Answer

Service (ClusterIP). A Service of type ClusterIP provides a stable virtual IP address and DNS name that load-balances traffic to a set of pods. Since the requirement is internal cluster access with a stable IP, ClusterIP is the correct choice — it exposes the pods on a cluster-internal IP that other services can reach reliably, without needing external exposure.

Answer

Ingress

Answer

Deployment

Answer

Pod

Question 10

A DevOps engineer has created a ConfigMap named 'app-config' and wants to use it to set environment variables in a pod. Which field in the pod spec should reference the ConfigMap?

Accepted Answer

spec.containers[].envFrom. `spec.containers[].envFrom` allows you to inject all key-value pairs from a ConfigMap (or Secret) as environment variables into a container in a single declaration. This field supports a `configMapRef` that references the ConfigMap by name, making it the appropriate spec field for bulk environment variable injection.

Answer

spec.containers[].command

Answer

spec.containers[].env.name

Answer

spec.containers[].volumeMounts

Question 11

You notice that a pod is in 'Pending' state for a long time. Which of the following is the most likely cause?

Accepted Answer

No node has enough CPU or memory to meet the pod's requests.. A pod remains in 'Pending' state when the scheduler cannot find a node that satisfies its resource requests. The most common reason is insufficient CPU or memory capacity across all available nodes, preventing the pod from being bound to a node. Unlike probe failures or missing images, which cause 'Running' or 'ImagePullBackOff' states, resource constraints block scheduling entirely.

Answer

The pod's liveness probe is failing.

Answer

The pod's readiness probe is not configured.

Answer

The container image does not exist.

Question 12

You create a Deployment with 'replicas: 3' and update the pod template to use a new image. After the rollout, you notice that the new ReplicaSet has 3 pods but they are all failing with 'CrashLoopBackOff'. You want to rollback to the previous working revision. Which command should you run?

Accepted Answer

kubectl rollout undo deployment/my-deployment. `kubectl rollout undo deployment/my-deployment` reverts the Deployment to the previous revision, which is the standard Kubernetes method to roll back a failed rollout. This command restores the pod template from the last working ReplicaSet, effectively undoing the change that caused the CrashLoopBackOff.

Answer

kubectl set image deployment/my-deployment nginx=nginx:1.21

Answer

kubectl delete deployment/my-deployment --cascade=false

Answer

kubectl rollout pause deployment/my-deployment

Question 13

A pod is running but you need to view the contents of a file '/var/log/app.log' inside the container to debug an issue. Which kubectl command allows you to do this without modifying the pod?

Accepted Answer

kubectl exec pod-name -- cat /var/log/app.log. `kubectl exec pod-name -- cat /var/log/app.log` runs the `cat` command inside the container without modifying the pod or its state. This allows you to view the file contents directly from the container's filesystem, which is essential for debugging when the application logs are not written to stdout/stderr and thus not accessible via `kubectl logs`.

Answer

kubectl logs pod-name -c container-name --tail=100

Answer

kubectl cp pod-name:/var/log/app.log -

Answer

kubectl attach pod-name

Question 14

You need to ensure that a pod runs on a specific node that has an SSD. The node has the label 'disktype=ssd'. How should you configure the pod to target this node?

Accepted Answer

Set spec.nodeSelector with disktype: ssd.. `spec.nodeSelector` is the simplest and most direct way to constrain a Pod to run only on nodes that have a specific label. By setting `disktype: ssd` in the nodeSelector, the scheduler will only consider nodes with that exact label key-value pair, ensuring the Pod lands on an SSD-equipped node.

Answer

Set spec.affinity.nodeAffinity with requiredDuringSchedulingIgnoredDuringExecution.

Answer

Set spec.tolerations with key=disktype, value=ssd.

Answer

Set spec.nodeName to the node's name.

Question 15

Which two of the following are benefits of using Kubernetes for container orchestration? (Select TWO.)

Accepted Answer

Self-healing: automatically restarts failed containers. Option C is correct because Kubernetes provides self-healing through controllers such as ReplicaSets and Deployments: when a container or Pod fails, the kubelet and control-plane reconciliation loop detect the deviation from the desired state and automatically restart or replace the failed container to maintain the declared replica count. Option E is correct because Kubernetes supports automated rollouts and rollbacks via Deployment objects, where changes to the Pod template trigger a rolling update (using maxSurge/maxUnavailable) and `kubectl rollout undo` reverts to a previous ReplicaSet revision. The unmarked options do not belong: A is incorrect because Kubernetes is an orchestration platform, not a CI system (CI is handled by tools like Jenkins, GitLab CI, or Tekton), B is incorrect because Kubernetes does not compile source code—it runs pre-built container images, and D is incorrect because Kubernetes does not provide built-in database management; stateful databases require operators or external services.

Answer

Integrated continuous integration pipeline

Answer

Automatic code compilation

Answer

Built-in database management