Azure App Service Monitoring - MSDN Documentation

Monitoring Azure App Service

This document provides a comprehensive guide to monitoring your Azure App Service applications, covering key metrics, tools, and best practices for ensuring optimal performance and availability.

Introduction to App Service Monitoring

Azure App Service offers a robust set of tools and features to monitor the health, performance, and usage of your web applications, APIs, and mobile backends. Effective monitoring is crucial for identifying and resolving issues proactively, optimizing resource utilization, and maintaining a high-quality user experience.

Key Monitoring Metrics

Several metrics are essential for understanding the behavior of your App Service. These can be viewed directly in the Azure portal or accessed programmatically.

CPU Time: The total amount of CPU time consumed by your application instances. High CPU usage can indicate performance bottlenecks or resource exhaustion.
Memory Working Set: The amount of physical memory currently used by your application processes. Excessive memory usage can lead to application slowdowns or crashes.
HTTP Server Errors (5xx): The number of server-side errors returned by your application. These often indicate application bugs or infrastructure issues.
HTTP Requests: The total number of HTTP requests processed by your application.
Data In/Out: The amount of data sent to and received from your application.
Average Response Time: The average time it takes for your application to respond to HTTP requests.

Azure Monitor Integration

Azure Monitor is the unified monitoring solution for Azure resources. It collects and analyzes telemetry from your App Service, allowing you to gain deep insights into its operation.

Application Insights

Application Insights, part of Azure Monitor, provides powerful Application Performance Management (APM) capabilities. It automatically detects performance anomalies, includes rich application mapping, and allows for code-level diagnostics.

To enable Application Insights:

Navigate to your App Service in the Azure portal.
Under the "Monitoring" section, select "Application Insights".
Click "Turn on Application Insights" and follow the prompts to create or link an existing Application Insights resource.

Once enabled, Application Insights offers features like:

Live Metrics Stream: Real-time performance data.
Performance Analysis: Identifying slow requests and dependencies.
Failure Analysis: Pinpointing exceptions and error rates.
Usage Analytics: Understanding user behavior and traffic patterns.

Azure Monitor Metrics and Alerts

You can also leverage Azure Monitor's core metrics and alerting features:

Metrics Explorer: Visualize trends for key metrics over time.
Alert Rules: Configure alerts based on metric thresholds or activity logs. For example, you can set an alert if CPU time exceeds 80% for 15 minutes.

To set up alerts:

Navigate to your App Service and select "Alerts" under "Monitoring".
Click "+ Create alert rule".
Define the condition (e.g., "HTTP Server Errors > 5 in the last 5 minutes").
Specify the action group (e.g., send an email or trigger a webhook).

Diagnostic Logs

App Service generates various diagnostic logs that provide detailed information for troubleshooting.

Application Logs: Logs generated by your application code.
Web Server Logs: Logs from the underlying web server (IIS for Windows, Nginx/Apache for Linux).
Detailed Error Messages: Captures detailed error information for HTTP status codes like 400 or 500.
Failed Request Tracing: Detailed tracing of failed HTTP requests.

You can configure diagnostic settings to send these logs to Log Analytics workspaces, Storage accounts, or Event Hubs for long-term storage and analysis.

Best Practices for Monitoring

To effectively monitor your App Service:

Set up comprehensive alerts: Don't just monitor, be notified. Configure alerts for critical metrics and error conditions.
Use Application Insights: Leverage its APM capabilities for deep application insights.
Establish baseline performance: Understand what normal performance looks like for your application to easily spot deviations.
Monitor dependencies: If your app relies on other services (databases, external APIs), monitor those as well.
Regularly review logs: Proactively analyze logs to identify potential issues before they impact users.
Utilize auto-scale: Configure auto-scaling rules based on monitoring metrics to handle fluctuating demand.

Tip: Regularly check the "Diagnose and solve problems" blade in the Azure portal. It offers automated troubleshooting for common App Service issues.

Important: Ensure your application is configured to emit meaningful logs. Logging is the foundation of effective monitoring.

Conclusion

Effective monitoring of your Azure App Service is a continuous process that involves understanding key metrics, utilizing powerful tools like Azure Monitor and Application Insights, and adhering to best practices. By implementing these strategies, you can ensure your applications remain performant, reliable, and available to your users.