Why Application Monitoring Matters
Traditional infrastructure monitoring (CPU, memory, network) isn’t enough for cloud-native applications. Modern apps are distributed across APIs, services, and databases — failures may occur at any layer.
Azure Application Insights is an Application Performance Monitoring (APM) service that provides deep visibility into how applications behave. It helps detect performance bottlenecks, diagnose issues, and improve user experience.
For a Solution Architect, the design decision is not about writing queries but about when and how to use Application Insights in solution designs.
Core Features of Application Insights
1. Request and Dependency Tracking
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Monitors incoming HTTP requests to your app.
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Tracks outgoing calls to dependencies like SQL, Storage, REST APIs.
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Helps identify which service is slowing down the overall response.
2. Performance Metrics
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Page load times, server response times, dependency latency.
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Identifies slow database queries or failing endpoints.
3. Exception and Failure Monitoring
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Captures exceptions, stack traces, and failure rates.
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Alerts when error thresholds are exceeded.
4. Usage Analytics
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Tracks number of users, sessions, geography.
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Helps align business goals (user engagement, adoption).
5. Distributed Tracing
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Correlates requests across microservices.
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Critical in containerized (AKS) or service-based apps.
6. Integration with DevOps
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Works with Azure DevOps and GitHub Actions.
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Enables continuous monitoring in CI/CD pipelines.
Designing Application Insights into Solutions
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Instrumentation
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Embed SDKs into application code (Java, .NET, Node.js, Python).
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Alternatively, enable “agent-based” monitoring (no code changes).
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Data Retention and Storage
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Logs are sent to a Log Analytics Workspace (LAW).
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Retention must be designed based on compliance.
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Alerting and Dashboards
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Create alerts based on application performance thresholds.
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Use dashboards to give developers and business teams visibility.
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Global Apps Consideration
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For multi-region apps, deploy multiple Application Insights instances near users to reduce latency in telemetry collection.
Example Enterprise Scenario
A global e-commerce website wants to:
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Track checkout failures.
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Monitor API response time across regions.
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Correlate front-end issues with back-end service failures.
Correct design:
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Enable Application Insights in the web app and APIs.
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Use distributed tracing to follow requests across services.
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Configure alerts for error rates above 5% in checkout API.
Confusion Buster
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Application Insights vs Azure Monitor
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Application Insights = APM for apps.
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Azure Monitor = umbrella platform for all telemetry.
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Application Insights vs Log Analytics
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App Insights collects telemetry from apps.
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Log Analytics stores/query logs from multiple sources.
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App Insights vs Metrics
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Metrics = CPU/Memory.
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App Insights = app performance and user behavior.
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Exam Tips
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“Which service monitors app performance and dependencies?” → Application Insights.
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“Company wants to trace requests across multiple services.” → App Insights with distributed tracing.
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“Business team wants usage analytics (sessions, geography).” → App Insights.
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“Company wants real-time CPU utilization of VM” → Azure Monitor metrics, not App Insights.
What to Expect in the Exam
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Direct Q: “Which Azure service is best for monitoring distributed app performance?” → Application Insights.
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Scenario Q: “Company wants to detect checkout failures and correlate across services.” → App Insights.
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Trick Q: “Application Insights and Azure Monitor are separate, unrelated tools.” → False (App Insights is part of Azure Monitor).