You have a web app that runs in Azure. You need to identify the amount of time it takes for web pages to load in a user's browser. What should you…

Application Insights, a feature of Azure Monitor, is an Application Performance Management (APM) service designed for web developers. It provides comprehensive monitoring for live web applications. By instrumenting your web app with the Application Insights JavaScript SDK, you can collect client-side telemetry directly from users' browsers. This includes crucial performance data such as the time it takes for web pages to load, browser exceptions, and AJAX call performance. This service directly addresses the need to identify and analyze user-side page load times, providing insights into the end-user experience.

A. Azure Monitor alerts: Alerts are a notification mechanism. They react to predefined conditions based on metrics or logs but do not perform the primary function of collecting the performance data itself.

C. Azure Network Watcher: This service provides tools to monitor and diagnose conditions at a network infrastructure level (e.g., VMs, virtual networks), not for application-level, client-side performance monitoring.

D. Log Analytics: Log Analytics is a tool for querying and analyzing log data from various sources. While Application Insights can send data to it, Application Insights is the specific service that collects the required telemetry.

1. Microsoft Learn | Application Insights for web pages: "Application Insights is an extensible Application Performance Management (APM) service... Use it to monitor your live web application. It will automatically detect performance anomalies... The SDK includes modules that collect different kinds of telemetry... Page views are sent by the client-side JavaScript in your web pages. They can be used to generate reports on page usage."

Source: Microsoft Learn, "Application Insights for web pages", Section: "How it works".

2. Microsoft Learn | Usage analysis with Application Insights: "Find out what users are doing with your app... Get page view, session, and user counts. Find out which pages are most popular. If you're using the JavaScript SDK, you can see how long it takes for pages to load in the user's browser."

Source: Microsoft Learn, "Usage analysis with Application Insights", Section: "Users, sessions, and page views".

3. Microsoft Learn | What is Azure Network Watcher?: "Azure Network Watcher provides tools to monitor, diagnose, view metrics, and enable or disable logs for resources in an Azure virtual network."

Source: Microsoft Learn, "What is Azure Network Watcher?", Introduction paragraph.

4. Microsoft Learn | Overview of alerts in Microsoft Azure: "This article describes what alerts are, their benefits, and how to get started using them. Alerts proactively notify you when important conditions are found in your monitoring data."

Source: Microsoft Learn, "Overview of alerts in Microsoft Azure", Section: "What are alerts in Microsoft Azure?".