Linkerd Observability Quiz
This quiz tests your understanding of Linkerd observability features.
Quiz Questions
1. Which is NOT a golden metric automatically collected by Linkerd?
A. Success rate B. Request rate (RPS) C. Latency D. CPU usage
Show Answer
Answer: D. CPU usage
Explanation: Linkerd automatically collects three golden metrics: success rate, request rate (RPS), and latency (p50, p95, p99). CPU usage is a Kubernetes metric that must be collected separately.
2. What is NOT included in the linkerd viz stat command output?
A. SUCCESS (success rate) B. RPS (request rate) C. LATENCY_P99 D. ERROR_TYPE
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Answer: D. ERROR_TYPE
Explanation:linkerd viz stat shows MESHED, SUCCESS, RPS, LATENCY_P50/P95/P99. Error types must be checked via linkerd viz tap or logs.
3. What is the purpose of the linkerd viz tap command?
A. Network packet capture B. View real-time request stream C. Change proxy configuration D. Renew certificates
Show Answer
Answer: B. View real-time request stream
Explanation:linkerd viz tap streams requests in real-time. It shows request method, path, status code, latency, mTLS status, and more.
4. What additional metrics can be obtained by defining a ServiceProfile?
A. Pod resource usage B. Per-route metrics C. Network bandwidth D. Disk I/O
Show Answer
Answer: B. Per-route metrics
Explanation: Defining a ServiceProfile enables collection of per-route (e.g., GET /api/users, POST /api/orders) success rate, request rate, and latency metrics. View with linkerd viz routes command.
5. What is the default method to access the Viz extension's Prometheus?
A. NodePort service B. LoadBalancer service C. kubectl port-forward D. Public URL
Show Answer
Answer: C. kubectl port-forward
Explanation: Viz's Prometheus is deployed as a ClusterIP service. Access via kubectl port-forward -n linkerd-viz svc/prometheus 9090:9090. External exposure is not recommended for security.
6. Which header is NOT required for distributed tracing propagation?
A. x-b3-traceid B. x-request-id C. x-linkerd-proxy D. x-b3-spanid
Show Answer
Answer: C. x-linkerd-proxy
Explanation: Headers needed for distributed tracing: x-request-id, x-b3-traceid, x-b3-spanid, x-b3-parentspanid, x-b3-sampled, b3, etc. x-linkerd-proxy doesn't exist.
7. What does the linkerd viz top command show?
A. Pods using most resources B. Most active request paths C. Top error messages D. Latest log entries
Show Answer
Answer: B. Most active request paths
Explanation:linkerd viz top shows the most active request paths in real-time. It displays Source, Destination, Method, Path, Count, Latency, Success Rate, etc.
8. What annotation sets the proxy log level?
A. config.linkerd.io/log-level B. config.linkerd.io/proxy-log-level C. linkerd.io/proxy-log D. proxy.linkerd.io/log-level
Show Answer
Answer: B. config.linkerd.io/proxy-log-level
Explanation: The config.linkerd.io/proxy-log-level annotation sets the proxy log level. Example: "warn,linkerd=info,linkerd_proxy=debug"
9. What is the correct Prometheus query to calculate Linkerd success rate?
A. sum(response_total{classification="success"}) / sum(response_total) B. rate(success_total[5m]) / rate(request_total[5m]) C. sum(rate(response_total{classification="success"}[5m])) / sum(rate(response_total[5m])) D. avg(success_rate)
Show Answer
Answer: C. sum(rate(response_total{classification="success"}[5m])) / sum(rate(response_total[5m]))
Explanation: Success rate is calculated by dividing successful response rate by total response rate. The rate() function calculates per-second rate within the time range, and sum() aggregates.
10. What is the main function of the Jaeger extension?
A. Metrics collection B. Log aggregation C. Distributed tracing D. Traffic splitting
Show Answer
Answer: C. Distributed tracing
Explanation: The Jaeger extension provides distributed tracing. It visualizes the complete path of requests through multiple services and analyzes latency at each step.
11. Which view is NOT provided by the linkerd viz dashboard command?
A. Topology B. Deployments C. Pod Logs D. Routes
Show Answer
Answer: C. Pod Logs
Explanation: The Viz dashboard provides Namespace, Deployments, Pods, TCP, Routes, Topology, and Tap views. Pod logs must be checked via kubectl logs or a separate logging system.
12. What Viz installation option is used when integrating with external Grafana?
A. --set grafana.external=true B. --set grafana.enabled=false C. --set grafana.url=external D. --set monitoring=external
Show Answer
Answer: B. --set grafana.enabled=false
Explanation: When using external Grafana, disable Viz's built-in Grafana. Use helm install linkerd-viz linkerd/linkerd-viz --set grafana.enabled=false or configure in values file.