KCNA Practice Test 24 — 15 Questions

Question 1

What is the main advantage of using OpenTelemetry over vendor-specific instrumentation libraries?

Accepted Answer

It provides a single, vendor-agnostic instrumentation standard. OpenTelemetry provides a unified standard that avoids vendor lock-in, allowing data to be sent to any backend.

Answer

It eliminates the need for logging

Answer

It automatically reduces latency

Answer

It is the only tool that supports traces

Question 2

Which GitOps tool is specifically designed for Kubernetes and follows the declarative GitOps pattern, continuously reconciling the desired state from a Git repository?

Accepted Answer

ArgoCD. ArgoCD is a declarative GitOps continuous delivery tool for Kubernetes that syncs application state with a Git repository.

Answer

Helm

Answer

Terraform

Answer

Jenkins

Question 3

Which THREE of the following are features provided by a service mesh like Istio? (Select THREE.)

Accepted Answer

Traffic routing and load balancing. Service mesh provides traffic management (routing), observability (metrics, tracing), and security (mTLS, policies).

Answer

Container image building

Answer

Database schema migrations

Question 4

In a serverless architecture using Knative, what happens when a function finishes processing an event and there are no pending events?

Accepted Answer

The function instance is automatically scaled down to zero replicas. Knative scales the function to zero replicas when idle, which is a key feature of serverless platforms.

Answer

The function instance is terminated and the container image is deleted

Answer

The function continues to run but stops listening for events

Answer

The function instance remains running for a configurable idle timeout

Question 5

Which of the following is a resiliency pattern that limits the number of concurrent requests to a service to prevent overload?

Accepted Answer

Bulkhead. Bulkhead isolates resources into pools (e.g., thread pools) so that a failure in one pool does not cascade. Circuit breaker stops calls after failures, retry repeats failed calls, and timeout limits wait time.

Answer

Retry

Answer

Timeout

Answer

Circuit breaker

Question 6

What is the primary benefit of using an API gateway in a microservices architecture?

Accepted Answer

It provides a single entry point for client requests and handles cross-cutting concerns. An API gateway acts as a single entry point for clients, providing request routing, composition, and cross-cutting concerns like authentication and rate limiting.

Answer

It replaces the need for service meshes

Answer

It stores application state

Answer

It performs service-to-service communication

Question 7

What is the role of an API gateway in a microservices architecture?

Accepted Answer

To provide a single entry point for external clients to access multiple backend services. An API gateway acts as a single entry point for client requests, handling routing, authentication, rate limiting, and other cross-cutting concerns.

Answer

To schedule pods on nodes

Answer

To store application configuration

Answer

To monitor container resource usage

Question 8

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.

Answer

Grafana

Answer

Fluentd

Answer

Prometheus

Question 9

In the context of resiliency patterns, which pattern is designed to prevent a cascade of failures by isolating each component so that a failure in one component does not affect others?

Accepted Answer

Bulkhead. The bulkhead pattern isolates resources (e.g., thread pools, connections) so that a failure in one part of the system doesn't bring down other parts. Circuit breaker is for handling failures of external calls, not isolation.

Answer

Retry

Answer

Circuit breaker

Answer

Timeout

Question 10

Which THREE of the following are components of the GitOps workflow? (Choose three.)

Accepted Answer

A CI/CD pipeline that validates changes before merging. GitOps relies on a Git repository as single source of truth, a CI/CD pipeline to validate changes, and an operator to sync the cluster.

Answer

A configuration management database (CMDB)

Answer

A manual approval process for every change

Question 11

Which Helm command is used to upgrade a release to a newer version of a chart?

Accepted Answer

helm upgrade. The 'helm upgrade' command upgrades an existing release with a new chart version or configuration.

Answer

helm rollback

Answer

helm update

Answer

helm install

Question 12

An application is instrumented with OpenTelemetry to export traces to Jaeger. The team notices that some traces are incomplete. What is the most likely cause?

Accepted Answer

Context propagation is not correctly implemented. Incomplete traces often occur when context propagation is not implemented correctly, causing spans to be disconnected.

Answer

Span attributes are missing

Answer

Sampling rate is too high

Answer

Jaeger database is full

Question 13

Which TWO of the following are valid PromQL functions? (Select two.)

Accepted Answer

histogram_quantile(). rate() and histogram_quantile() are common PromQL functions. avg_over_time() is also valid but avg is not a function, it's an aggregation operator.

Answer

topk()

Answer

avg()

Answer

sum()

Question 14

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

Accepted Answer

kubectl logs app-pod -c sidecar. The -c flag specifies the container name. The correct command is 'kubectl logs app-pod -c sidecar'.

Answer

kubectl log app-pod --container sidecar

Answer

kubectl logs app-pod sidecar

Answer

kubectl logs -c sidecar app-pod

Question 15

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