KCNA Practice Test 45 — 15 Questions

Question 1

What is a key benefit of using containers over virtual machines for application deployment?

Accepted Answer

Containers are more lightweight and start faster than VMs. Containers share the host OS kernel and run as isolated processes, requiring no separate guest OS per instance. This makes them significantly more lightweight and faster to start than VMs, which must boot a full guest OS. For application deployment, this translates to higher density, lower resource overhead, and near-instant startup times.

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Containers can only run on Linux

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Containers require a hypervisor to run

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Containers provide stronger isolation than VMs

Question 2

Which of the following is the correct definition of a Service Level Indicator (SLI)?

Accepted Answer

A quantitative measure of a specific aspect of the service's reliability. An SLI is a quantitative measure of a specific aspect of a service's reliability — for example, request latency, error rate, or availability — expressed as a ratio of good events to total events. It is the raw measurement that feeds into SLOs and error budgets, not a contract or a target.

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A formal contract between a service provider and a customer

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A target value or range for a metric, agreed upon with stakeholders

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A tool for aggregating logs from multiple sources

Question 3

A DevOps team wants to adopt a deployment pattern where a new version of an application is gradually rolled out to a small subset of users before full deployment. Which progressive delivery technique should they use?

Accepted Answer

Canary deployment. Canary deployment is the progressive delivery technique that routes a small percentage of live traffic to the new version while the majority continues to hit the stable version. This allows the team to observe real-user metrics (error rates, latency, business KPIs) on a limited blast radius before promoting the release to 100% of users. It is the canonical pattern for gradual, risk-controlled rollouts.

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Rolling update

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Blue-green deployment

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Recreate deployment

Question 4

Which Kubernetes object provides a stable IP address and DNS name to access a set of pods, and can perform load balancing?

Accepted Answer

Service. A Service is the correct Kubernetes object because it provides a stable virtual IP (ClusterIP) and a DNS name (via CoreDNS) that remains constant even as pods are created or destroyed. It performs layer 4 (TCP/UDP) load balancing across the set of pods selected by its label selector, using iptables or IPVS rules to distribute traffic.

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Ingress

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Deployment

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Pod

Question 5

Which tool is specifically designed for distributed tracing and is a Cloud Native Computing Foundation (CNCF) graduated project?

Accepted Answer

Jaeger. Jaeger is a CNCF graduated project focused on distributed tracing.

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Grafana

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Fluentd

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Prometheus

Question 6

Which TWO of the following are best practices for structuring log output in cloud-native applications to maximize observability?

Accepted Answer

Output logs in structured format such as JSON. Option C is correct because emitting logs as structured data such as JSON lets log processors and observability backends parse fields programmatically, enabling reliable filtering, aggregation, and indexing by attributes like severity, service, and trace context rather than relying on fragile regex over free text. Option D is correct because including a unique request or correlation ID (for example a W3C traceparent trace ID or an application-generated correlation ID) in every entry allows distributed traces and logs to be stitched together across microservices, which is essential for root-cause analysis in cloud-native systems. The remaining options are not best practices: A floods storage and cost with low-value debug noise and can obscure real signals, B breaks line-oriented log collectors and parsers that expect one event per line, and E removes timestamps that are required to order events and correlate them across services and time zones.

Answer

Include verbose debug-level information in every log line

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Use multi-line log entries for detailed error information

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Avoid timestamps to reduce log size

Question 7

A team uses a Deployment with 3 replicas and a RollingUpdate strategy. They update the container image. During the update, one of the new pods fails to start. What will happen by default?

Accepted Answer

The update pauses, keeping the remaining old replicas running. By default, a Deployment with a RollingUpdate strategy uses a `maxUnavailable` of 25% and a `maxSurge` of 25%. When a new pod fails to start (e.g., CrashLoopBackOff or ImagePullBackOff), the ReplicaSet controller will not create additional new pods beyond the surge limit, and the update will effectively pause because the new ReplicaSet cannot reach its desired replica count. The old ReplicaSet remains running with its existing pods, ensuring availability is maintained.

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The entire update is rolled back and all old pods are deleted

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The Deployment automatically rolls back to the previous image

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The failed pod is terminated and not retried

Question 8

A retail company runs its e-commerce platform on Kubernetes. During a flash sale, the application experiences high latency. The team notices that the database pods are CPU-bound and the application pods are waiting on database responses. Which architectural change would best address this bottleneck?

Accepted Answer

Implement read replicas for the database and configure the application to use them for read operations.. The bottleneck is caused by the database being CPU-bound, meaning it cannot process requests fast enough. Implementing read replicas offloads read queries from the primary database, reducing its CPU load and allowing it to handle write operations more efficiently. The application can be configured to route read operations to the replicas, which directly addresses the latency caused by waiting on database responses.

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Change the database service type from ClusterIP to NodePort.

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Increase the number of application pod replicas.

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Store database configuration in a ConfigMap to improve startup time.

Question 9

Which Kubernetes object should you use to store non-sensitive configuration data that can be consumed by Pods as environment variables or mounted files?

Accepted Answer

ConfigMap. ConfigMap is the correct Kubernetes object for storing non-sensitive configuration data, such as key-value pairs or configuration files. It is designed to decouple configuration artifacts from container images, allowing Pods to consume this data as environment variables, command-line arguments, or mounted files in a volume. Unlike Secrets, ConfigMaps do not provide encryption or base64 encoding by default, making them suitable only for non-sensitive information.

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Secret

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PersistentVolume

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Service

Question 10

A pod is stuck in the 'Pending' state. Which command would you use to get more details about why the pod cannot be scheduled?

Accepted Answer

kubectl describe pod . `kubectl describe pod ` provides detailed event logs and status information, including scheduler decisions, resource constraints, and node conditions that explain why a pod remains in 'Pending' state. The 'Pending' state typically indicates the pod has not been scheduled, and `kubectl describe` surfaces the exact reason, such as insufficient CPU/memory, persistent volume claims not bound, or node selector mismatches.

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kubectl logs <pod-name>

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kubectl exec -it <pod-name> -- sh

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kubectl get pod <pod-name> -o yaml

Question 11

Which TWO of the following are principles of the 12-factor app methodology? (Choose two.)

Accepted Answer

Ensure fast startup and graceful shutdown (disposability). Option C is correct because the 12-factor methodology's Disposability factor explicitly requires processes to start fast and shut down gracefully, enabling rapid scaling, quick deployment of new code, and resilience to sudden termination. Option E is correct because the Config factor mandates storing configuration in the environment (environment variables) rather than in code, so the same build can be deployed across environments without modification. Option A is wrong because 12-factor apps favor automated, repeatable deployments and CI/CD, not manual deployment. Option B is wrong because 12-factor apps should be stateless processes, storing any needed state in backing services such as databases or caches, not in sticky sessions. Option D is wrong because 12-factor apps are typically decomposed into smaller, independent services rather than built as a single monolith.

Answer

Perform manual deployment to avoid automation errors

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Maximize robustness through stateful sessions

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Build monolithic applications for simplicity

Question 12

Which TWO statements about Namespaces are correct?

Accepted Answer

Resource names must be unique within a namespace. Option A is correct because within a single namespace, resource names (for a given resource type) must be unique — for example, you cannot have two Pods both named 'web' in the same namespace, though the same name can exist in different namespaces. Option D is correct because namespaces are intended to divide cluster resources among multiple users or teams, commonly combined with ResourceQuota and RBAC to scope access and limit consumption per namespace. Option B is not correct because namespaces do not provide network isolation by default; Pods across namespaces can communicate freely unless NetworkPolicies are applied. Option C is not correct because not all resources are namespaced — cluster-scoped resources such as Nodes, PersistentVolumes, and ClusterRoles exist outside any namespace. Option E is not correct because deleting a namespace deletes all resources contained within it, so it does affect the resources inside.

Answer

Namespaces provide network isolation by default

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All Kubernetes resources are namespaced

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You can delete a namespace without affecting the resources inside it

Question 13

You want to deploy a stateless web application that should maintain 5 running instances at all times. You need to support rolling updates and rollbacks. Which Kubernetes resource is most appropriate?

Accepted Answer

Deployment. A Deployment is the correct choice because it is designed to manage stateless applications with a desired replica count (5 instances), supports rolling updates to update pods gradually without downtime, and enables rollbacks to a previous revision if an update fails. Deployments internally create ReplicaSets to manage pod scaling and versioning, making them ideal for stateless workloads requiring high availability and update flexibility.

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DaemonSet

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ReplicaSet

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StatefulSet

Question 14

Which TWO components are part of the Kubernetes control plane? (Choose two.)

Accepted Answer

kube-apiserver. The Kubernetes control plane consists of components that make global cluster decisions and manage cluster state, and kube-apiserver (C) is the central control plane component that exposes the Kubernetes API and is the front end through which all other components communicate. kube-controller-manager (D) is also a control plane component; it runs the built-in controllers (such as node, replication, endpoints, and service account controllers) that continuously reconcile the desired state stored in etcd with the actual cluster state. By contrast, kube-proxy (A) is a node-level component that maintains network rules (iptables/IPVS) for Service load balancing, the container runtime (B) is node software like containerd or CRI-O that actually runs containers, and kubelet (E) is the node agent that registers the node and manages pods on it — all three run on worker nodes rather than as part of the control plane.

Answer

kube-proxy

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container runtime

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kubelet

Question 15

You need to create a ConfigMap from a file named 'app.properties'. Which kubectl command should you use?

Accepted Answer

kubectl create configmap my-config --from-file=app.properties. `kubectl create configmap` with the `--from-file` flag creates a ConfigMap from a file, using the filename as the key and its content as the value. This is the standard way to import a properties file into a ConfigMap in Kubernetes.

Answer

kubectl create configmap my-config --from-literal=app.properties

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kubectl create configmap my-config --file=app.properties

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kubectl create configmap my-config --from-env-file=app.properties