KCNA Practice Test 48 — 15 Questions

Question 1

A company deploys a microservice application on Kubernetes. They notice that one of the services is returning 5xx errors intermittently. Which observability tool should they use to correlate the errors with resource usage across all pods of that service?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Prometheus. Prometheus is the correct choice because it is a monitoring and alerting toolkit designed to collect and store time-series metrics, such as CPU, memory, and request error rates. By querying Prometheus with PromQL, you can correlate 5xx error spikes with resource usage across all pods of a service, as it scrapes metrics from each pod's /metrics endpoint. This direct correlation of application-level errors with infrastructure metrics is not natively provided by the other tools listed.

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Grafana

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Fluentd

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Jaeger

Question 2

Which two of the following are valid ways to set resource constraints on a container in a Pod spec?

Accepted Answer

Specify 'resources.limits.memory' for maximum memory. 'resources.limits.memory' is the valid Kubernetes field to set the maximum amount of memory a container can use. When a container exceeds this limit, it may be terminated or OOM-killed by the kubelet. This is a core concept in Kubernetes resource management for ensuring predictable application behavior.

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Specify 'resources.guarantees.cpu' for CPU guarantees

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Specify 'resources.min.memory' for minimum memory

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Specify 'resources.max.cpu' for CPU limits

Question 3

Which TWO of the following are essential components of a GitOps workflow? (Select two.)

Accepted Answer

An operator that synchronizes the cluster state with the Git repository. A GitOps workflow relies on an operator (such as Argo CD or Flux) that continuously reconciles the actual cluster state with the desired state declared in a Git repository. This operator automatically detects drift and applies changes to ensure the cluster matches the Git source, which is the core feedback loop of GitOps.

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A separate database for storing desired state

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A monitoring dashboard for visualizations

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A CI/CD pipeline that manually applies changes

Question 4

Which command creates a Deployment named 'nginx-deployment' from the image 'nginx:1.25' and exposes it on port 80?

Accepted Answer

kubectl create deployment nginx-deployment --image=nginx:1.25 --port=80. The `kubectl create deployment` command is the standard way to create a Deployment resource in Kubernetes. The `--image=nginx:1.25` flag specifies the container image, and the `--port=80` flag sets the container port in the pod template spec, which allows the Deployment to expose the container on port 80.

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kubectl run nginx-deployment --image=nginx:1.25 --port=80

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kubectl apply -f nginx-deployment.yaml

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kubectl expose deployment nginx-deployment --type=ClusterIP

Question 5

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.

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kubectl describe pod my-pod

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kubectl run my-pod -- logs

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kubectl attach my-pod

Question 6

Which TWO of the following are valid container runtimes that implement the CRI? (Choose two.)

Accepted Answer

CRI-O. CRI-O is a lightweight container runtime specifically designed to implement the Kubernetes Container Runtime Interface (CRI), allowing Kubernetes to use OCI-compliant runtimes directly without relying on Docker. It is a valid CRI implementation because it provides the gRPC-based CRI API server and manages container lifecycle using runc or Kata Containers as the underlying OCI runtime.

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Kata Containers

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Docker

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rkt

Question 7

Which TWO are benefits of using a service mesh in cloud-native applications?

Accepted Answer

Advanced traffic management capabilities. A service mesh provides advanced traffic management capabilities such as fine-grained routing, canary deployments, and circuit breaking through sidecar proxies (e.g., Envoy). These capabilities allow operators to control traffic flow between microservices without modifying application code, enabling resilient and observable communication patterns.

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Eliminates need for application monitoring

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Simplified persistent storage management

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Reduced network latency

Question 8

Which of the following is a core component of the three pillars of observability?

Accepted Answer

Logs. The three pillars of observability are logs, metrics, and traces. Alerting is derived from metrics, not a pillar itself.

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Alerting

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SLIs

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Dashboards

Question 9

Which Prometheus metric type is best suited to count the number of HTTP requests received?

Accepted Answer

Counter. A counter is a cumulative metric that only increases, ideal for counting requests.

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Gauge

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Histogram

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Summary

Question 10

You need to update a running Deployment to use a new container image. Which kubectl command should you use?

Accepted Answer

kubectl set image deployment/ =. `kubectl set image` is the dedicated command for updating the container image of a running Deployment without modifying the entire manifest. It directly updates the Deployment's pod template spec, triggering a rolling update to replace pods with the new image.

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kubectl replace -f deployment.yaml

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kubectl edit deployment <name>

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kubectl patch deployment -p '{"spec":{"template":{"spec":{"containers":[{"name":"","image":""}]}}}}'

Question 11

A development team wants to implement a GitOps workflow for their Kubernetes deployments. Which tool is specifically designed for GitOps on Kubernetes?

Accepted Answer

ArgoCD. ArgoCD is a declarative GitOps tool built specifically for Kubernetes.

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Helm

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Jenkins

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Terraform

Question 12

A Kubernetes cluster runs a critical application that must be updated with zero downtime. The team wants to gradually shift traffic from the old version to the new version over a period of time. Which deployment pattern is MOST appropriate?

Accepted Answer

Canary deployment. Canary deployment involves rolling out the new version to a small subset of users initially and gradually increasing traffic while monitoring for issues. This minimizes risk and provides control over the rollout.

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Rolling update

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Recreate deployment

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Blue-green deployment

Question 13

Which of the following is NOT one of the three pillars of observability?

Accepted Answer

Alerts. The three pillars are logs, metrics, and traces. Alerts are derived from these pillars but not considered a pillar themselves.

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Metrics

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Logs

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Traces

Question 14

Which of the following is an example of Infrastructure as Code (IaC) tool?

Accepted Answer

Terraform. Terraform is a widely used IaC tool that allows declarative definition of infrastructure across multiple cloud providers.

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Kubernetes

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Docker

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Prometheus

Question 15

What is the concept of 'immutable infrastructure' as applied to Kubernetes?

Accepted Answer

Pods are replaced with new versions rather than being modified. Immutable infrastructure in Kubernetes means that instead of modifying running Pods or their containers (e.g., patching a binary or updating a config file in place), you replace the entire Pod with a new version. This is enforced by Kubernetes' declarative model: when you update a Deployment's Pod template, the controller creates new Pods with the new image and terminates the old ones. This ensures consistency, repeatability, and eliminates configuration drift, as every change results in a fresh, identical instance from the same image.

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Configuration is stored in environment variables only

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Containers are rebuilt from the same base image every time

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Infrastructure components are never replaced; they are updated in place