KCNA Cloud Native Observability Practice Test 4 — 15 Questions

Question 1

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 2

Which TWO of the following are examples of context propagation mechanisms used in distributed tracing?

Accepted Answer

HTTP headers. HTTP headers, such as the `traceparent` and `tracestate` headers defined in the W3C Trace Context specification, are the standard mechanism for propagating trace context across service boundaries in distributed tracing. When a service receives an incoming HTTP request, it extracts the trace ID and span ID from these headers to continue the same trace. This allows trace data to be correlated across multiple microservices as the request flows through the system.

Answer

Environment variables

Answer

Database queries

Answer

Shared filesystem

Question 3

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 4

A DevOps team wants to collect logs from all Kubernetes nodes and forward them to a central log storage system. Which tool is specifically designed for lightweight log aggregation and forwarding on Kubernetes nodes?

Accepted Answer

Fluent Bit. Fluent Bit is a lightweight log processor and forwarder, designed for resource-constrained environments like Kubernetes nodes.

Answer

Elasticsearch

Answer

Prometheus

Answer

Grafana

Question 5

A company uses OpenTelemetry to instrument their microservices. They want to ensure that traces from one service can be correlated with those from another service across network calls. Which OpenTelemetry concept enables this correlation?

Accepted Answer

Context propagation. Context propagation allows trace context to be passed between services, enabling distributed tracing correlation.

Answer

Exporter configuration

Answer

Span attributes

Answer

Sampling

Question 6

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 a metric that can go up and down, like memory usage or temperature.

Answer

Histogram

Answer

Summary

Answer

Counter

Question 7

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 8

A team wants to set up alerts when a Kubernetes pod consumes more than 90% of its memory limit for over 5 minutes. They use Prometheus and Alertmanager. Which Prometheus query would trigger an alert for a specific pod named 'web-app' in the 'default' namespace?

Accepted Answer

container_memory_usage_bytes{pod='web-app'} / container_spec_memory_limit_bytes{pod='web-app'} > 0.9. The correct query divides container memory usage by its limit and compares to 0.9.

Answer

container_memory_usage_bytes{pod='web-app'} > 0.9

Answer

avg(container_memory_usage_bytes{pod='web-app'}) > 0.9

Answer

container_memory_limit_bytes{pod='web-app'} > 0.9

Question 9

Which component of the OpenTelemetry architecture is responsible for receiving data from instrumented applications and processing it before export?

Accepted Answer

OpenTelemetry Collector. The OpenTelemetry Collector receives, processes, and exports telemetry data.

Answer

OpenTelemetry SDK

Answer

OpenTelemetry API

Answer

OpenTelemetry exporter

Question 10

What is the purpose of the metrics-server in Kubernetes?

Accepted Answer

To provide resource usage metrics for pods and nodes. The metrics-server provides resource metrics (CPU and memory) per pod and node, used by kubectl top and the Horizontal Pod Autoscaler.

Answer

To manage service meshes

Answer

To collect application logs

Answer

To store historical metrics

Question 11

A team wants to visualize metrics from Prometheus in a dashboard. Which tool is commonly used for this purpose?

Accepted Answer

Grafana. Grafana is the most popular visualization tool for Prometheus metrics, offering rich dashboards.

Answer

Alertmanager

Answer

Jaeger UI

Answer

Kibana

Question 12

A company defines an SLO that 99.9% of requests to a service should complete in under 200ms. Which metric type is used to measure this SLO?

Accepted Answer

Histogram. The SLO is based on latency, which is typically measured using a histogram to track request durations.

Answer

Summary

Answer

Gauge

Answer

Counter

Question 13

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 14

What does the 'kubectl logs' command retrieve?

Accepted Answer

Container logs. kubectl logs fetches the standard output and standard error logs from a container in a pod.

Answer

Audit logs

Answer

Cluster events

Answer

Node logs

Question 15

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