Instiq
Chapter 5 · Troubleshooting and Optimization·v2.1.0·Updated 6/28/2026·~9 min

What's changed: In-scope service coverage (axis B): added Athena/OpenSearch Service large-scale log-analysis definitions, roles, and selection criteria to s1 (CloudWatch).

5.1Observability with CloudWatch

Key points

Understand observability basics: CloudWatch Logs / Logs Insights, metrics and alarms, and custom metrics. The starting point for "Troubleshooting and Optimization" in DVA-C02.

To find and fix problems fast, you must see your app’s logs, metrics, and traces. The AWS core is Amazon CloudWatch.

5.1.1Logs, metrics, and traces

Diagram of three pillars: logs (CloudWatch Logs; app/Lambda output; query with Logs Insights), metrics & alarms (numeric time-series; alarm on thresholds; custom metrics too), and traces (AWS X-Ray; end-to-end request path; find slow segments).
CloudWatch observability
  • Logs: CloudWatch Logs aggregates app/Lambda output; query/analyze with Logs Insights.
  • Metrics/alarms: collect numeric time-series and alarm on threshold breaches (notify, autoscale).
  • Custom metrics: send app-specific metrics (e.g., order count) to monitor.
Exam point

Common on DVA: aggregate/query logs = CloudWatch Logs / Logs Insights, notify/auto-respond on thresholds = CloudWatch alarms, app-specific = custom metrics. Lambda logs go to CloudWatch Logs automatically.

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