KCNA Practice Test 34 — 15 Questions

Question 1

Which Kubernetes control plane component is responsible for maintaining the desired state of the cluster, such as ensuring the correct number of pods are running?

Accepted Answer

kube-controller-manager. The kube-controller-manager is the control plane component that runs controller processes, including the Replication Controller, which is responsible for ensuring that the desired number of pod replicas are running at all times. It continuously watches the state of the cluster via the kube-apiserver and makes adjustments to reconcile the current state with the desired state defined in the cluster's configuration.

Answer

kube-apiserver

Answer

kube-scheduler

Answer

etcd

Question 2

Which kubectl command would you use to view the logs of a specific container named 'app' in a multi-container Pod named 'web-pod'?

Accepted Answer

kubectl logs web-pod -c app. The `kubectl logs` command uses the `-c` flag to specify a container name within a multi-container Pod. The correct syntax is `kubectl logs -c `, which targets the 'app' container inside 'web-pod'.

Answer

kubectl log web-pod container app

Answer

kubectl logs web-pod app

Answer

kubectl logs app web-pod

Question 3

An administrator wants to ensure that a specific pod only runs on nodes that have solid-state drives (SSDs). Nodes with SSDs are labeled with 'disktype=ssd'. Which pod specification field should be used?

Accepted Answer

nodeSelector. The `nodeSelector` field in a Pod spec is the simplest and most direct way to constrain a Pod to nodes with specific labels. By setting `nodeSelector: { disktype: ssd }`, the scheduler will only place the Pod on nodes that have the label `disktype=ssd`, which matches the administrator's requirement exactly. This field is a hard constraint that does not support complex expressions, but it is ideal for straightforward label-based node selection.

Answer

container resource limits

Answer

tolerations

Answer

nodeAffinity

Question 4

What is the primary purpose of a Namespace in Kubernetes?

Accepted Answer

To isolate resources and provide a scope for names. Namespaces in Kubernetes provide a mechanism for isolating groups of resources within a single cluster. They create separate scopes for resource names, meaning that resource names (like Pods or Services) only need to be unique within a Namespace, not across the entire cluster. This allows multiple teams or projects to share a cluster without naming conflicts, and it also enables cluster administrators to apply policies (like ResourceQuotas) and network policies at the Namespace level.

Answer

To set resource quotas for the entire cluster

Answer

To define network policies for pods

Answer

To manage node affinity rules

Question 5

Which Kubernetes object provides stable network endpoints and load balancing for a set of pods?

Accepted Answer

Service. A Service is the correct Kubernetes object because it provides a stable virtual IP (ClusterIP) and DNS name that remains constant even as pods are created or destroyed. It automatically load-balances traffic across the set of pods matching its label selector using iptables or IPVS rules, ensuring reliable network endpoints for clients.

Answer

Deployment

Answer

ConfigMap

Answer

Pod

Question 6

Which component of the Kubernetes control plane is responsible for persisting the cluster state?

Accepted Answer

etcd. etcd is the distributed key-value store that acts as the single source of truth for the entire Kubernetes cluster. It stores all cluster state data, including configuration, secrets, and the desired state of every object, ensuring consistency and durability. The kube-apiserver is the only component that directly interacts with etcd, enforcing a strict serialization of writes to prevent corruption.

Answer

kube-scheduler

Answer

kube-controller-manager

Answer

kube-apiserver

Question 7

Which THREE are typical characteristics of a cloud-native application?

Accepted Answer

Packaged as lightweight containers. Cloud-native applications are typically packaged as lightweight containers (e.g., Docker) that encapsulate the application and its dependencies, enabling fast startup, portability, and efficient resource utilization. Containers share the host OS kernel and have minimal overhead compared to virtual machines, which aligns with the cloud-native principle of agility and scalability.

Answer

Long startup times due to heavy initialization

Answer

Vulnerable to cascading failures

Question 8

Drag and drop the steps to perform a backup of etcd in a Kubernetes cluster into the correct order.

Accepted Answer

Access the node, Save snapshot, Verify, Store securely. Access the node, save snapshot, verify, store securely, and restore when necessary.

Answer

Save snapshot, Verify, Access the node, Store securely

Answer

Access the node, Store securely, Save snapshot, Verify

Answer

Verify, Access the node, Save snapshot, Store securely

Question 9

A team is designing a cloud-native system that must maintain high availability across multiple cloud regions. The application uses Kubernetes clusters in each region. Which approach best ensures that the system can tolerate a full region failure while minimizing complexity?

Accepted Answer

Use a global load balancer with active-passive regional failover. A global load balancer with active-passive regional failover provides a straightforward way to route traffic to a healthy secondary region when the primary fails, without the complexity of multi-region Kubernetes control planes or synchronous replication. This approach leverages DNS-based or anycast routing to detect region failure and redirect traffic, ensuring high availability while keeping the operational overhead low.

Answer

Deploy a single Kubernetes cluster spanning all regions

Answer

Run active-active in all regions with synchronous data replication

Answer

Implement manual failover procedures documented in runbooks

Question 10

A team wants to implement cost monitoring for their Kubernetes clusters. Which approach is most effective?

Accepted Answer

Use cloud provider billing APIs combined with resource utilization data. Cloud provider billing APIs provide actual cost data per resource (e.g., per node, per persistent volume, per network egress), and combining this with resource utilization data (e.g., CPU/memory requests and actual usage from metrics) enables accurate cost allocation per namespace, pod, or workload. This approach directly maps infrastructure spend to Kubernetes abstractions, which is essential for chargeback or showback in multi-tenant clusters.

Answer

Use kubectl top to get resource usage

Answer

Estimate costs based on node count

Answer

Monitor CPU and memory usage with Prometheus

Question 11

You have a Pod with a container that needs to read sensitive data such as a database password. Which Kubernetes resource should you use to store this data?

Accepted Answer

Secret. A Secret is the correct Kubernetes resource for storing sensitive data like database passwords because it encodes the data in base64 and is designed to be consumed by Pods via environment variables or volume mounts. Unlike ConfigMaps, Secrets are intended for confidential information and can be encrypted at rest using etcd encryption providers or KMS.

Answer

PersistentVolume

Answer

ServiceAccount

Answer

ConfigMap

Question 12

You have a Deployment that manages 3 replicas. You want to perform a rolling update with a maximum of 2 Pods unavailable during the update. Which field should you set in the Deployment spec?

Accepted Answer

spec.strategy.rollingUpdate.maxUnavailable. The `maxUnavailable` field in `spec.strategy.rollingUpdate.maxUnavailable` specifies the maximum number of Pods that can be unavailable during a rolling update. Setting it to 2 allows up to 2 Pods to be taken down at a time, ensuring that at least 1 Pod remains available (since the Deployment has 3 replicas). This field directly controls the availability tolerance during the update process.

Answer

spec.minReadySeconds

Answer

spec.strategy.rollingUpdate.maxSurge

Answer

spec.replicas

Question 13

Which TWO of the following are benefits of using a container orchestration platform like Kubernetes? (Select 2)

Accepted Answer

Self-healing of failed containers. Kubernetes includes a built-in controller loop that continuously monitors the desired state of workloads. If a container or pod fails, the ReplicaSet or StatefulSet controller automatically replaces it by rescheduling a new pod, ensuring application availability without manual intervention.

Answer

Manual deployment of containers to servers

Answer

Requirement for a hypervisor on every node

Answer

Static infrastructure that never changes

Question 14

Which THREE are benefits of using a container orchestration platform? (Select 3)

Accepted Answer

Declarative configuration management. Options B, C, and E are correct. Declarative configuration management (B) allows you to define the desired state and the platform ensures it. Automated scaling based on demand (C) adjusts resources automatically. High availability through automatic failover (E) ensures minimal downtime. Option A is incorrect—orchestration does not guarantee zero downtime. Option D is incorrect—orchestration does not eliminate the need for infrastructure.

Answer

Guarantees zero downtime during deployments

Answer

Eliminates the need for cloud infrastructure

Question 15

What is the purpose of a readiness probe in a Kubernetes pod?

Accepted Answer

To determine if the container is ready to serve traffic. A readiness probe in Kubernetes determines whether a container inside a pod is ready to start accepting 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 distinct from a liveness probe, which checks if the container is healthy and should be restarted.

Answer

To check if the pod has been scheduled on a node

Answer

To measure the CPU and memory usage of the container

Answer

To determine if the container is healthy and should be restarted