KCNA Kubernetes Fundamentals Practice Test 29 — 15 Questions

Question 1

Which TWO components run on every worker node in a Kubernetes cluster?

Accepted Answer

kubelet. The kubelet is the primary node agent that runs on every worker node, responsible for managing pod lifecycle and ensuring containers are running as expected. kube-proxy runs on every node to handle network routing and load balancing for Kubernetes services, implementing rules via iptables or IPVS.

Answer

kube-scheduler

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etcd

Answer

kube-apiserver

Question 2

An administrator wants to perform a rolling update of a Deployment. Which TWO actions will achieve this?

Accepted Answer

Run 'kubectl set image deployment/myapp myapp=myapp:v2'. 'kubectl set image deployment/myapp myapp=myapp:v2' directly updates the container image in the Deployment's pod template, which triggers a rolling update by default. The Deployment controller then creates a new ReplicaSet with the updated image and gradually scales it up while scaling down the old ReplicaSet, ensuring zero downtime.

Answer

Run 'kubectl scale deployment myapp --replicas=0' then 'kubectl scale deployment myapp --replicas=5'

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Run 'kubectl delete deployment' and then 'kubectl create deployment' with the new image

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Run 'kubectl rollout undo deployment/myapp'

Question 3

Which THREE statements about Labels and Selectors are correct?

Accepted Answer

Services use selectors to determine which Pods receive traffic. A Kubernetes Service uses a label selector to identify which Pods should receive traffic. When a Service is created with a selector matching certain labels, the endpoint controller dynamically updates the Service's Endpoints object to include the IP addresses of all Pods with those labels, enabling traffic routing.

Answer

Labels must be unique within a namespace

Answer

Annotations are used for identification and selection

Question 4

Which TWO of the following are characteristics of a Namespace in Kubernetes?

Accepted Answer

Resource names must be unique within a namespace, but can be reused across namespaces. Namespaces in Kubernetes provide a mechanism for logical grouping and scoping of resources. Two key characteristics are: (1) resource names must be unique within a namespace but can be reused across different namespaces (option C), and (2) namespaces allow multiple virtual clusters (logical clusters) within a single physical cluster (option D). While deleting a namespace does delete all its contained objects (option E), this is a consequence of namespace lifecycle management rather than a defining characteristic of what a namespace is. Network isolation is not provided by default; it requires explicit NetworkPolicy resources.

Answer

Namespaces are required for all Kubernetes objects

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Namespaces provide network isolation by default

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Deleting a namespace deletes all objects inside it

Question 5

A user reports that a web application is not accessible via its Service. The Service is of type ClusterIP. Which TWO steps should be taken to troubleshoot?

Accepted Answer

Verify that the kube-proxy is running on the node. Kube-proxy is the component responsible for implementing the ClusterIP Service abstraction by managing iptables or IPVS rules on each node. If kube-proxy is not running, traffic destined for the Service's ClusterIP will not be forwarded to the backend pods, making the Service unreachable from within the cluster.

Answer

Check that the container runtime is working

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Check the kube-apiserver status

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Restart all nodes in the cluster

Question 6

Which TWO of the following are valid ways to view the logs of a pod named 'my-pod'?

Accepted Answer

kubectl exec my-pod -- cat /var/log/app.log. `kubectl exec my-pod -- cat /var/log/app.log` runs the `cat` command inside the container of the pod, allowing you to read a specific log file directly from the filesystem. This is a valid method when the application writes logs to a file rather than stdout/stderr, or when you need to inspect a log file that is not captured by the standard logging driver.

Answer

kubectl describe pod my-pod

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kubectl run my-pod -- logs

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kubectl attach my-pod

Question 7

Which THREE of the following are responsibilities of the kube-controller-manager?

Accepted Answer

Creating Endpoints objects for Services. The kube-controller-manager includes the EndpointSlice controller (or the legacy Endpoints controller), which is responsible for creating and updating Endpoints (and EndpointSlice) objects to reflect the IP addresses and ports of Pods that match a Service's label selector. This ensures that the Service's DNS or iptables rules point to healthy Pods.

Answer

Assigning Pods to Nodes

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Serving the Kubernetes API

Question 8

Which Kubernetes component is responsible for maintaining the desired state of the cluster by running controller loops?

Accepted Answer

kube-controller-manager. The kube-controller-manager is the component that runs controller loops to regulate the state of the cluster. Each controller (e.g., Node Controller, Replication Controller) watches the shared state via the API server and makes changes to drive the actual cluster state toward the desired state defined in the control plane. This is the core mechanism for self-healing and maintaining declarative configuration.

Answer

etcd

Answer

kube-apiserver

Answer

kube-scheduler

Question 9

A pod in the 'production' namespace is in a CrashLoopBackOff state. The pod has been running successfully for several days. You run 'kubectl describe pod app-pod -n production' and see the message: 'OOMKilled'. What is the MOST appropriate action to resolve this issue?

Accepted Answer

Increase the memory limit in the pod's container resource specification. The pod is in CrashLoopBackOff due to OOMKilled, which means the container's memory usage exceeded its configured memory limit. The most appropriate action is to increase the memory limit in the pod's container resource specification, allowing the container to use more memory without being terminated by the Out-Of-Memory (OOM) killer. This directly addresses the root cause—insufficient memory allocation—while preserving the existing pod configuration and data.

Answer

Delete and recreate the pod to clear the crash loop

Answer

Delete the namespace and redeploy all workloads

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Increase the CPU request for the container

Question 10

You have a Deployment that runs a web application. You need to expose this application externally on a fixed port using a cloud load balancer. Which Service type should you use?

Accepted Answer

LoadBalancer. A LoadBalancer Service type provisions an external cloud load balancer (e.g., AWS ELB, GCP TCP/UDP Load Balancer) that exposes the application on a fixed port (typically 80/443) and distributes traffic to the Pods. This is the correct choice because the requirement explicitly asks for a cloud load balancer with a fixed external port, which is exactly what LoadBalancer provides by integrating with the underlying cloud provider's API.

Answer

NodePort

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ExternalName

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ClusterIP

Question 11

When creating a Deployment, you want to ensure that only a certain number of pods run at a time across all nodes. Which field in the Deployment spec controls this?

Accepted Answer

spec.replicas. The `spec.replicas` field in a Deployment spec defines the desired number of identical Pod replicas that should be running at any given time. This field directly controls the count of Pods across all nodes in the cluster, ensuring that exactly that many Pods are maintained by the ReplicaSet controller. Option A is correct because it is the only field that sets the target Pod count.

Answer

spec.selector

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spec.minReadySeconds

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spec.template

Question 12

You are asked to schedule a pod on a node that has SSD storage. Which mechanism should you use to achieve this?

Accepted Answer

Add a nodeSelector with a label matching the node, e.g., disktype: ssd. NodeSelector is the built-in Kubernetes mechanism for constraining a pod to nodes with specific labels. By labeling a node with disktype=ssd and adding that same label selector to the pod spec, the scheduler will only place the pod on nodes that have that label, ensuring it lands on SSD-equipped nodes.

Answer

Use a resource request for SSD storage capacity

Answer

Set an annotation on the pod specifying the disk type

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Add a toleration for a taint on SSD nodes

Question 13

Which TWO components are part of a Kubernetes worker node?

Accepted Answer

kubelet. The kubelet is the primary node agent that runs on every worker node. It registers the node with the cluster, receives Pod specifications from the API server, and ensures that the containers described in those Pods are running and healthy. Without the kubelet, a node cannot participate in the cluster as a worker.

Answer

kube-scheduler

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container runtime

Answer

etcd

Question 14

Which THREE of the following are valid options for the 'kubectl get' command to display output in different formats?

Accepted Answer

-o wide. `kubectl get -o wide` is a valid output format that displays additional details such as node names and internal IPs for pods, or cluster IPs and ports for services, beyond the default summary columns. This is a standard kubectl output flag for human-readable extended output.

Answer

-o verbose

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--describe

Question 15

Which THREE statements about Kubernetes Services are correct?

Accepted Answer

A Service provides a stable IP address and DNS name for a set of Pods.. A is correct because a Kubernetes Service provides a stable virtual IP address and a DNS name (via CoreDNS) that remains constant even as the underlying Pods are created, destroyed, or scaled. This decouples clients from the ephemeral nature of Pod IPs, ensuring reliable connectivity.

Answer

A Service can only route traffic to Pods within the same namespace.

Answer

The default Service type is NodePort.