Why Application Insights?
Monitoring infrastructure is important, but if applications fail or perform poorly, end users feel the pain first. Application Insights (part of Azure Monitor) provides Application Performance Monitoring (APM) to track availability, performance, and usage of apps.
It’s especially useful for developers and architects to detect issues early, understand dependencies, and optimize performance.
Application Insights Overview
Definition:
A service within Azure Monitor for collecting application telemetry (performance, availability, usage, exceptions).
What It Monitors:
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Request rates, response times, failure rates.
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Exceptions and error logs.
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Dependency calls (SQL, APIs, storage).
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Availability via synthetic tests (pings from global test agents).
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User behavior (page views, sessions, funnels).
Key Features
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APM (Application Performance Monitoring)
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Track app responsiveness (latency, exceptions).
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Drill down into slow API calls or failing dependencies.
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Dependency Tracking
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Map application components and dependencies.
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Example: Web app → SQL DB → Storage → External API.
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Live Metrics Stream
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Near real-time monitoring of requests, failures, CPU, memory.
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Availability Testing
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Synthetic tests simulate user traffic from multiple regions.
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Detect outages before customers report them.
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Smart Detection
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AI-based anomaly detection (e.g., sudden increase in failed logins).
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Example Enterprise Scenario
A global e-commerce app requires:
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Track checkout failures in real-time.
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Monitor API latency between app and SQL DB.
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Run availability tests from EU and US to ensure 24/7 uptime.
Correct design:
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Enable Application Insights SDK in app code.
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Use dependency tracking to pinpoint SQL latency.
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Create synthetic availability tests from EU/US.
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Set up alerts for checkout error spikes.
Confusion Buster
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Application Insights vs Log Analytics
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App Insights = application-level telemetry (APM).
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Log Analytics = infrastructure + system logs.
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Synthetic Testing vs Real User Monitoring
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Synthetic = simulated traffic (test availability).
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Real User = actual telemetry from real sessions.
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App Insights vs Azure Monitor (umbrella)
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App Insights = specialized APM service.
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Azure Monitor = covers metrics, logs, APM, alerts.
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Exam Tips
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“Which service provides application-level telemetry in Azure?” → Application Insights.
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“Which feature detects SQL latency in apps?” → Dependency Tracking.
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“Which feature simulates global user traffic to test availability?” → Synthetic tests.
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“Which feature detects anomalies with AI?” → Smart Detection.
What to Expect in the Exam
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Direct Q: “Which Azure service is used for APM?” → Application Insights.
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Scenario Q: “Company wants to monitor checkout failures in an e-commerce app.” → Application Insights with alerts.
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Scenario Q: “Company requires global uptime tests for their app.” → Synthetic availability testing.
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Trick Q: “Log Analytics can provide dependency tracking for SQL calls.” → False (App Insights does).