KCNA Practice Test 25 — 15 Questions

Question 1

Which THREE of the following are benefits of using a service mesh for observability? (Select three.)

Accepted Answer

Distributed tracing across services. A service mesh provides visibility into inter-service communication, adds distributed tracing without code changes, and collects metrics like request latency.

Answer

Reduced network latency

Answer

Centralized logging of all application logs

Question 2

A developer wants to view the logs of a specific container named 'sidecar' in a pod called 'web-app'. Which command should they use?

Accepted Answer

kubectl logs web-app -c sidecar. The -c flag specifies the container name when a pod has multiple containers.

Answer

kubectl logs sidecar --pod web-app

Answer

kubectl logs -c sidecar web-app

Answer

kubectl logs sidecar web-app

Question 3

Which THREE of the following are components of the OpenTelemetry project?

Accepted Answer

Collector. OpenTelemetry includes specification, SDKs, Collector, and instrumentations. Prometheus and Jaeger are separate projects.

Answer

Prometheus

Answer

Jaeger

Question 4

In Kustomize, what is the purpose of an overlay?

Accepted Answer

To apply patches and modifications on top of a base. Overlays in Kustomize allow you to define environment-specific customizations (e.g., dev, prod) on top of a common base configuration.

Answer

To template values using Go templates

Answer

To define the base set of Kubernetes resources shared across environments

Answer

To manage Helm releases

Question 5

Which of the following is considered one of the three pillars of observability?

Accepted Answer

Metrics. The three pillars of observability in cloud native environments are logs, metrics, and traces.

Answer

Events

Answer

Alerts

Answer

Profiles

Question 6

In the context of DORA metrics, which metric measures how often an organization successfully releases to production?

Accepted Answer

Deployment frequency. Deployment frequency is a DORA metric that measures how often an organization deploys code to production or an operational environment.

Answer

Lead time for changes

Answer

Mean time to restore (MTTR)

Answer

Change failure rate

Question 7

Which DORA metric measures the percentage of deployments that cause a failure in production?

Accepted Answer

Change failure rate. Change failure rate is the percentage of deployments that result in degraded service or require remediation.

Answer

Lead time for changes

Answer

Mean time to recover (MTTR)

Answer

Deployment frequency

Question 8

In Flux, which controller is responsible for reconciling the desired state defined in a Git repository to the cluster?

Accepted Answer

Kustomize Controller. Flux's Source Controller fetches artifacts (e.g., Git repositories, Helm repos) but does not apply changes. The Kustomize Controller is the primary controller that reconciles the desired state from those sources to the cluster.

Answer

Image Automation Controller

Answer

Source Controller

Answer

Helm Controller

Question 9

In a blue-green deployment strategy, at any given time, only one environment (blue or green) is active. What is the primary advantage of this approach?

Accepted Answer

Instant rollback by switching traffic back to the previous environment. Blue-green deployments allow instant rollback by switching traffic back to the previous environment. This is the primary advantage: if issues arise in the new version, you can immediately revert by pointing the router/load balancer to the old environment. Option A describes gradual traffic shifting, which is characteristic of canary deployments, not blue-green. Option C is incorrect because blue-green requires two full environments, doubling resource consumption. Option D is false because a load balancer or ingress controller is essential to switch traffic between the two environments.

Answer

Gradual traffic shifting to detect issues early

Answer

Minimal resource consumption by using only one environment

Answer

No need for load balancers or ingress controllers

Question 10

What is the primary purpose of continuous integration (CI) in a cloud-native application delivery pipeline?

Accepted Answer

To automatically build and test code changes upon commit. CI automates building and testing code changes upon commit to catch integration issues early. Option A correctly describes this. Option B refers to infrastructure provisioning, which is typically managed by Infrastructure as Code (IaC) tools. Option C refers to managing container images and registries, which is part of container management. Option D describes continuous deployment (CD), which automatically deploys code to production after passing CI.

Answer

To manage infrastructure provisioning

Answer

To manage container images and registries

Answer

To automatically deploy code changes to production

Question 11

Which THREE of the following are key capabilities of progressive delivery tools like Argo Rollouts?

Accepted Answer

Integration with feature flag systems. Progressive delivery tools enable traffic splitting, automated rollbacks based on metrics, and integration with feature flags.

Answer

Automatic image vulnerability scanning

Answer

Replacing the need for CI/CD pipelines

Question 12

Which command is used to rollback a Helm release to a previous revision?

Accepted Answer

helm rollback . The `helm rollback` command rolls back a release to a specified revision. Option B (helm rollback ) is the correct command. Option A (helm history) shows revision history, not a rollback. Option C (helm install) installs a new release. Option D (helm upgrade) upgrades to a new version, not a rollback.

Answer

helm history <release-name>

Answer

helm install <release-name>

Answer

helm upgrade <release-name>

Question 13

In a multi-cloud architecture, what is a common use case for a service mesh?

Accepted Answer

To enable secure service-to-service communication across clusters. A service mesh, such as Istio or Linkerd, provides a dedicated infrastructure layer for handling service-to-service communication. In a multi-cloud architecture, its common use case is to enable secure, observable, and resilient communication between services running in different Kubernetes clusters across clouds, using mutual TLS (mTLS) for encryption and traffic policies for routing.

Answer

To synchronize Kubernetes resources across clouds

Answer

To provide cloud-agnostic block storage

Answer

To provide a single ingress gateway for all clouds

Question 14

Match each Kubernetes object to its typical use case.

Accepted Answer

Deployment: Manage stateless applications with rolling updates and rollbacks. Correct matches: Deployment manages stateless apps with rolling updates; StatefulSet handles stateful apps with stable identities; DaemonSet runs a pod on every node. Common confusions: mixing Deployment with DaemonSet (one per node vs. stateless management) and StatefulSet with Jobs (stateful vs. batch).

Answer

Deployment: Ensure one pod per node in the cluster

Answer

StatefulSet: Run a batch job to completion

Question 15

An application requires a unique identifier per replica, stored in an environment variable. Which Kubernetes resource should be used to inject this identifier into each pod without manual updates?

Accepted Answer

StatefulSet with an environment variable derived from the pod name.. A StatefulSet provides stable, unique network identities and ordered pod naming (e.g., pod-0, pod-1). The pod name can be exposed as an environment variable using the Downward API or Kubernetes hostname field, giving each replica a unique identifier without manual updates. Deployments create identical pods with no ordering, DaemonSets run one pod per node, and Jobs are for batch processing, so only a StatefulSet meets the requirement.

Answer

Deployment with pod anti-affinity to schedule each pod on a different node.

Answer

DaemonSet with a node name environment variable.

Answer

Job with a completion index environment variable.