Once your application is deployed in a production environment, you want to make sure everything is working fine with it. You would like to analyze how many exceptions and errors are being thrown, how many requests are being handled, how many requests are being made, what is memory and CPU usage, and so on. In Azure, you can do all this by using the Application Insights tool.
You can see in the above image that your application components will publish the data to Application Insights service, from where you can create alerts, reports, or trigger other actions based on your need.
Setting up Application Insights need some instrumentation on your application side. Mostly it is as simple as importing the SDK and adding a config file. Here is a detailed explanation of how to implement it for a Java Project https://docs.microsoft.com/en-us/azure/azure-monitor/app/java-get-started?tabs=maven.
You can gather following information from Applications Insights.
- Request rates, response times, and failure rates
- Dependency rates, response times, and failure rates
- Pageviews and load performance
- AJAX calls
- User and session counts
- Performance counters
- Host diagnostics
- Diagnostic trace logs
- Custom events and metrics
For more information on Application Insights and usage with different languages – https://docs.microsoft.com/en-us/azure/azure-monitor/app/app-insights-overview