KCNA Practice Exam 55 — 20 Questions

Question 1

A container image is being pushed to a private registry. What is the correct workflow?

Accepted Answer

Build, tag, push. The standard workflow is: build image, tag it with registry URL, then push to registry.

Answer

Push first, then build

Answer

Push, tag, build

Answer

Tag after push

Question 2

An organization wants to implement a serverless function that scales to zero when not in use. Which technology is specifically designed to achieve this on Kubernetes?

Accepted Answer

Knative. Knative Serving supports scale-to-zero, automatically scaling down pods when they are not receiving requests. This is a key feature of serverless on Kubernetes.

Answer

Prometheus

Answer

Istio

Answer

Kubernetes Horizontal Pod Autoscaler (HPA)

Question 3

Which of the following best describes 'Infrastructure as Code' (IaC)?

Accepted Answer

Defining infrastructure resources in a declarative configuration file. IaC is the practice of managing and provisioning infrastructure through machine-readable definition files, rather than manual processes.

Answer

Manually configuring servers via SSH

Answer

Using a scripting language to automate tasks

Answer

Running containers on a Kubernetes cluster

Question 4

A development team wants to adopt a cloud-native architecture for a new application. Which set of principles BEST describes the cloud-native approach?

Accepted Answer

Microservices, containers, dynamic orchestration, and DevOps. Cloud-native architectures leverage microservices, containers, dynamic orchestration, and DevOps to enable scalable, resilient applications.

Answer

Service-oriented architecture, bare-metal servers, static scaling, and Agile

Answer

Monolithic applications, virtual machines, manual scaling, and waterfall development

Answer

Serverless functions, virtual machines, manual provisioning, and ITIL

Question 5

A Kubernetes Deployment is configured with 'strategy.type: RollingUpdate'. The team wants to ensure that during an update, no more than 25% of pods are unavailable at any time. Which specification should be added?

Accepted Answer

strategy.rollingUpdate.maxUnavailable: 25%. The 'maxUnavailable' field in the rolling update strategy controls how many pods can be unavailable during the update. Setting it to 25% ensures at most 25% are down.

Answer

spec.minReadySeconds: 30

Answer

spec.replicas: 4

Answer

strategy.rollingUpdate.maxSurge: 25%

Question 6

Which TWO actions can improve the DORA metric 'Mean Time to Recovery (MTTR)'?

Accepted Answer

Using feature flags to disable faulty code quickly. Reducing MTTR involves quick detection and rollback or fix of failures.

Answer

Increasing deployment frequency

Answer

Slowing down the release cycle

Answer

Adding more manual approval steps

Question 7

What is the primary purpose of a container registry in a CI/CD pipeline?

Accepted Answer

To host container images for deployment. A container registry stores and distributes container images. After building and scanning, images are pushed to a registry so that deployment tools can pull them to run containers.

Answer

To manage Kubernetes secrets

Answer

To store source code and trigger builds

Answer

To run CI/CD pipelines

Question 8

In an event-driven architecture using a message broker, which component is responsible for receiving events and forwarding them to subscribed services?

Accepted Answer

Message broker. A message broker (like Kafka or RabbitMQ) receives and forwards events. An API gateway routes HTTP requests, a service mesh handles service-to-service communication, and a load balancer distributes network traffic.

Answer

Service mesh

Answer

API gateway

Answer

Load balancer

Question 9

Which of the following is a benefit of using a service mesh?

Accepted Answer

Enhanced observability and traffic control. A service mesh provides observability (metrics, tracing), traffic management (routing, load balancing), and security (mTLS) without requiring changes to application code. It does not directly manage storage or scaling.

Answer

Simplified storage management

Answer

Automatic scaling of applications

Answer

Direct database access

Question 10

Which THREE of the following are components of the OpenTelemetry project? (Select three)

Accepted Answer

OpenTelemetry API. The OpenTelemetry project includes the API, SDK, and Collector. The Agent (as a separate component) and Exporter are part of the SDK/Collector, not standalone components.

Answer

OpenTelemetry Agent

Answer

OpenTelemetry Exporter

Question 11

Which TWO of the following are valid Prometheus metric types? (Select two)

Accepted Answer

Counter. Prometheus has four metric types: Counter, Gauge, Histogram, and Summary. Counter and Gauge are two of them.

Answer

Set

Answer

Timer

Answer

Meter

Question 12

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.

Question 13

Drag and drop the steps to create a Kubernetes deployment using kubectl into the correct order.

Accepted Answer

Create a YAML definition file, then run kubectl apply, then verify the deployment, then check pods, then expose the deployment as a service.. First, define the deployment in a YAML file, then apply it, verify creation, check pods, and optionally expose it as a service.

Answer

Create a YAML definition file, then verify the deployment, then run kubectl apply, then check pods, then expose the deployment as a service.

Answer

Run kubectl apply, then create a YAML definition file, then verify the deployment, then expose the deployment as a service, then check pods.

Answer

Create a YAML definition file, then run kubectl apply, then expose the deployment as a service, then check pods, then verify the deployment.

Question 14

A development team deploys a microservice that crashes every few minutes. The deployment uses a single replica, and the pod restarts repeatedly. Which Kubernetes feature should be enabled to ensure the service remains available during failures?

Accepted Answer

Increase the replicas in the Deployment to at least 2. Increasing the replicas to at least 2 ensures that if one pod crashes, the other replica(s) can continue serving traffic, maintaining availability. With only a single replica, the service becomes unavailable every time the pod restarts. This is the most direct way to provide redundancy and fault tolerance for a stateless microservice.

Answer

Move the deployment to a separate namespace

Answer

Store the application configuration in a ConfigMap

Answer

Add a readiness probe to the pod

Question 15

Match each CNCF project to its primary function.

Accepted Answer

Kubernetes: Container orchestration. The correct matches are: Kubernetes → Container orchestration, Envoy → Service proxy, Fluentd → Log collection. Common confusions include mixing Prometheus (monitoring) with Fluentd (logging) and CoreDNS (DNS) with Prometheus.

Answer

Prometheus: Log collection

Answer

CoreDNS: Monitoring and alerting

Question 16

Drag and drop the steps to configure a Kubernetes Service of type LoadBalancer in a cloud environment into the correct order.

Accepted Answer

Step 1: Deploy the application. Step 2: Define and create the LoadBalancer service. Step 3: Retrieve the external IP. Step 4: Access the application using the IP.. First deploy the app, then define and create the LoadBalancer service, retrieve the IP, and access it.

Answer

Step 1: Define and create the LoadBalancer service. Step 2: Deploy the application. Step 3: Retrieve the external IP. Step 4: Access the application.

Answer

Step 1: Retrieve the external IP. Step 2: Deploy the application. Step 3: Define and create the LoadBalancer service. Step 4: Access the application.

Answer

Step 1: Deploy the application. Step 2: Retrieve the external IP. Step 3: Define and create the LoadBalancer service. Step 4: Access the application.

Question 17

You have a Kubernetes cluster with multiple nodes. You need to ensure that a pod runs on a node that has an SSD. How should you achieve this?

Accepted Answer

Use a nodeSelector with the label 'disktype: ssd'. NodeSelector is the simplest and most direct way to constrain a Pod to run only on nodes that have a specific label, such as 'disktype=ssd'. When you add a nodeSelector field to the Pod spec, the kube-scheduler filters nodes that do not have the matching label, ensuring the Pod lands on a node with an SSD.

Answer

Manually edit kube-scheduler configuration

Answer

Use a DaemonSet to run the pod on all nodes

Answer

Use a toleration for the node

Question 18

The exhibit shows pod status and logs. The web pod lmn34 has restarted 3 times. What is the root cause of the liveness probe failure?

Accepted Answer

The database service is not reachable, causing the application to fail its health check.. The liveness probe failure is caused by the database service being unreachable, which prevents the application from completing its health check. When the database is down or network connectivity is lost, the application's health endpoint returns a non-200 status code, causing Kubernetes to restart the container. The 3 restarts indicate repeated probe failures, and the logs show connection errors to the database, confirming this as the root cause.

Answer

The container is hitting a memory limit and being OOMKilled.

Answer

A network policy is blocking traffic to the database.

Answer

The readiness probe is misconfigured and not allowing traffic.

Question 19

Match each Kubernetes resource to its primary purpose.

Accepted Answer

Pod: The smallest and simplest Kubernetes object, representing a set of running containers.. Pods are the smallest deployable units; Services provide stable networking to Pods; Deployments manage Pod lifecycle. Common confusions involve swapping Pod with Service, Service with ConfigMap, and Deployment with storage resources.

Answer

Pod: A method to expose a set of Pods as a network service.

Answer

Service: A resource that stores non-sensitive configuration data.

Answer

Deployment: A storage abstraction that provides persistent storage to Pods.

Question 20

A development team is designing a new microservices application to run on a Kubernetes cluster. They want to ensure that each microservice can be developed, deployed, and scaled independently. Which cloud native architecture principle are they primarily applying?

Accepted Answer

Loose coupling. The principle of loose coupling ensures that each microservice can be developed, deployed, and scaled independently by minimizing dependencies between services. In Kubernetes, this is achieved through well-defined APIs and service boundaries, allowing teams to update or scale one service without affecting others. This directly supports the team's goal of independent lifecycle management for each microservice.

Answer

Immutable infrastructure

Answer

Statelessness

Answer

Service discovery