Azure Monitor is a monitoring solution in the Azure portal that delivers a comprehensive solution for collecting, analyzing, and acting on telemetry from the cloud and on-premises environments. It can be used to monitor various aspects (for instance, the performance of applications) and identify issues affecting those applications and other resources that depend on them.

The data that is collected by Azure Monitor fits into two fundamental types: metrics and logs. Metrics describe an aspect of a system at a particular point in time and are displayed in numerical values. They are capable of supporting near real-time scenarios. Logs are different from metrics. They contain data that is organized into records, with different sets of properties for each type. Data such as events, traces, and performance data are stored as logs. They can then be combined for analysis purposes.

Azure Monitor supports data collection from a variety of Azure resources, which are all displayed on the overview page in the Azure portal. Azure Monitor provides the following metrics and logs:

• Application monitoring data: This will consist of data about the functionality and performance of the application and the code that is written, regardless of its platform.
• Guest OS monitoring data: This will consist of data about the operating system on which your application is running. This could be running in any cloud or on-premises environment.
• Azure resource monitoring data: This will consist of data about the operation of an Azure resource.
• Azure subscription monitoring data: This will consist of data about the operation and management of an Azure subscription, as well as data about the health and operation of Azure itself.
• Azure tenant monitoring data: This will consist of data about the operation of tenant-level Azure services, such as Azure Active Directory.

The following diagram gives a high-level view of Azure Monitor. On the left, there are the sources of monitoring data, in the center are the data stores, and on the right are the different functions that Azure Monitor performs with this collected data, such as analysis, alerting, and streaming to external systems:

Now that we have some basic knowledge about Azure Monitor, we are going to look at how to analyze alerts and metrics across subscriptions.