Azure Monitor

Azure Monitor is a platform for collecting data on your resources, analyzing that data, visualizing the information, and even acting on the results.
Azure Monitor can monitor Azure resources, your on-premises resources, and even multi-cloud resources like virtual machines hosted with a different cloud provider.
Data can be collected from application to operating system and network.
The logging and metric data are stored in central repositories.
You can view real-time and historical performances
You can view aggregated and detailed information.
You can view high-level reports on the Azure Monitor Dashboard or create custom views by using Power BI and Kusto queries.
You can use the data to help you react to critical events in real time
You can use thresholds to trigger autoscaling functionality to scale to meet the demand.

Azure Log Analytics

Azure Log Analytics is the tool in the Azure portal where you’ll write and run log queries on the data gathered by Azure Monitor.
Log Analytics is a robust tool that supports both simple, complex queries, and data analysis.
You can write a simple query that returns a set of records and then use features of Log Analytics to sort, filter, and analyze the records.
You can write an advanced query to perform statistical analysis and visualize the results in a chart to identify a particular trend.

Azure Monitor Alerts are an automated way to stay informed when Azure Monitor detects a threshold being crossed.
You set the alert conditions, the notification actions, and then Azure Monitor Alerts notifies when an alert is triggered.
Depending on your configuration, Azure Monitor Alerts can also attempt corrective action.
Alerts can be set up to monitor the logs or metrics
Azure Monitor, Service Health, and Azure Advisor all use actions groups to notify you when an alert has been triggered.
An action group is simply a collection of notification and action preferences that you associate with one or multiple alerts.

Application Insights, an Azure Monitor feature, monitors your web applications.
Application Insights is capable of monitoring applications that are running in Azure, on-premises, or in a different cloud environment.
There are two ways to configure Application Insights to help monitor your application. You can either install an SDK in your application, or you can use the Application Insights agent.
The Application Insights agent is supported in C#.NET, VB.NET, Java, JavaScript, Node.js, and Python.
Once Application Insights is up and running, you can use it to monitor a broad array of information, such as:
- Request rates, response times, and failure rates
- Dependency rates, response times, and failure rates, to show whether external services are slowing down performance
- Page views and load performance reported by users' browsers
- AJAX calls from web pages, including rates, response times, and failure rates
- User and session counts
- Performance counters from Windows or Linux server machines, such as CPU, memory, and network usage
You can also configure it to periodically send synthetic requests to your application, allowing you to check the status and monitor your application even during periods of low activity.