KCNA Practice Test 5 — 10 Questions

Question 1

Which service mesh component is responsible for handling inter-service communication as a sidecar proxy?

Accepted Answer

Envoy. Envoy is the correct answer because it is the sidecar proxy component in Istio that handles all inter-service communication. It intercepts traffic between microservices and applies routing, load balancing, and security policies defined by the control plane. Envoy runs as a sidecar container alongside each service instance, managing inbound and outbound traffic at the L4/L7 layer.

Answer

Mixer

Answer

Pilot

Answer

Citadel

Question 2

What is the smallest deployable unit in Kubernetes that can be created, scheduled, and managed?

Accepted Answer

Pod. A Pod is the smallest and simplest unit in the Kubernetes object model that can be created, scheduled, and managed. It represents a single instance of a running process in the cluster and encapsulates one or more containers with shared storage and network resources. While containers are the underlying runtime, Kubernetes does not schedule containers directly; it schedules Pods as the atomic unit of deployment.

Answer

Deployment

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Node

Answer

Container

Question 3

Which THREE of the following are benefits of structured logging? (Select three.)

Accepted Answer

Easier querying and filtering. Structured logging emits events as key-value pairs (typically JSON), so option A is correct because fields like level, service, or trace_id can be queried and filtered directly in tools such as Elasticsearch, Loki, or CloudWatch Logs Insights without fragile regex parsing. Option D is correct because that same machine-parseable format lets log processors, SIEMs, and observability pipelines ingest and index records programmatically and reliably. Option E is correct because adopting a shared schema with consistent field names across services enables correlation and aggregation across distributed systems, which is a core goal of structured logging. Option B is not a benefit: structured logs are usually less human-readable than free-form plain text, which is why pretty-printers exist. Option C is not a benefit either: JSON key-value output typically increases log size versus terse plain-text lines due to repeated field names and delimiters, so storage requirements usually grow rather than shrink.

Answer

More human-readable than plain text

Answer

Reduced storage requirements

Question 4

A company is deploying a microservices application on Kubernetes. They want to ensure that configuration data, such as database URLs and feature flags, can be updated without rebuilding container images. Which Kubernetes resource should they use?

Accepted Answer

ConfigMaps. ConfigMaps are the correct Kubernetes resource for decoupling configuration data (like database URLs and feature flags) from container images. They allow you to inject configuration as environment variables or mounted volumes without rebuilding or redeploying the container image, enabling runtime updates.

Answer

Secrets

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Services

Answer

Deployments

Question 5

Which Prometheus metric type is used to represent a value that can increase or decrease over time, such as memory usage?

Accepted Answer

Gauge. A gauge is the Prometheus metric type designed to represent a value that can arbitrarily go up or down, such as memory usage, temperature, or current connections. Unlike counters, gauges are not monotonic and can be set to any value, making them ideal for instantaneous measurements. Memory usage fluctuates as processes allocate and free memory, so a gauge accurately captures this behavior.

Answer

Histogram

Answer

Summary

Answer

Counter

Question 6

A Deployment named 'app-deploy' is configured with strategy type: RollingUpdate. You want to update the container image to a new version. What kubectl command should you use?

Accepted Answer

kubectl set image deployment/app-deploy app=new:tag. `kubectl set image` is the dedicated command for updating the container image of an existing deployment without modifying other fields. It directly modifies the deployment's pod template spec to use the new image, triggering a rolling update as defined by the deployment's strategy type.

Answer

kubectl apply -f updated-deployment.yaml

Answer

kubectl edit deployment app-deploy

Answer

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

Question 7

Which Prometheus metric type is best suited for counting the total number of HTTP requests received by a service?

Accepted Answer

Counter. A counter is a cumulative metric that only increases (or resets to zero). It is ideal for counting events like HTTP requests.

Answer

Summary

Answer

Gauge

Answer

Histogram

Question 8

A pod is stuck in 'Pending' state. You run 'kubectl describe pod mypod' and see the event '0/4 nodes are available: 4 Insufficient cpu'. What is the most likely cause?

Accepted Answer

None of the nodes have enough CPU resources to satisfy the pod's request. The '0/4 nodes are available: 4 Insufficient cpu' event directly indicates that the Kubernetes scheduler attempted to place the pod on each of the four nodes but found that none had enough allocatable CPU capacity to satisfy the pod's CPU request (specified in the container's `resources.requests.cpu`). This causes the pod to remain in 'Pending' state because the scheduler cannot find a feasible node.

Answer

The pod has exceeded its memory limit

Answer

The pod's image pull is failing

Answer

The pod's liveness probe is failing

Question 9

Which of the following is a core principle of the 12-factor app methodology?

Accepted Answer

Treat logs as event streams. The 12-factor app methodology, a set of best practices for building modern, scalable applications, includes the principle 'Treat logs as event streams.' This means an app should not concern itself with routing or storage of its output stream; instead, it writes logs to stdout/stderr, and the execution environment captures and routes them. This decouples log management from the application, enabling flexibility and scalability.

Answer

Store configuration in the application code

Answer

Store logs in the local filesystem of each container

Answer

Use shared filesystems for persistent storage

Question 10

Which of the following describes the Open Container Initiative (OCI) image specification?

Accepted Answer

A standard for container images and runtimes. The Open Container Initiative (OCI) image specification defines a standard format for container images, ensuring that any OCI-compliant image can be run by any OCI-compliant runtime (e.g., runc, crun). This specification covers the image manifest, filesystem layers, and configuration, enabling interoperability across different container platforms like Docker, Podman, and containerd. Option A is correct because the OCI specifically standardizes both the image format and the runtime behavior, not higher-level orchestration or infrastructure concerns.

Answer

A specification for container orchestration

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A specification for container storage

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A specification for container networking