Overview of the Azure Monitor agents

Compute resources such as virtual machines generate data to monitor their performance and availability just like other cloud resources. Compute resources though also have a guest operating system and workloads that need to be monitored. Collecting this monitoring data from inside the resource requires an agent. This article describes the agents used by Azure Monitor and helps you determine which you need to meet the requirements for your particular environment.

Summary of agents

Note

Azure Monitor currently has multiple agents because of recent consolidation of Azure Monitor and Log Analytics. Both agents share some capabilities while other features are unique to a particular agent. Depending on your requirements, you may need one of the agents or both.

Azure Monitor has three agents that each provide specific functionality. Depending on your requirements, you may install a single agent or multiple on your virtual machines and other compute resources.

The following table provides a quick comparison of the different agents. See the rest of this article for details on each.

Azure Diagnostic Extension Log Analytics agent Dependency agent
Environments supported Azure Azure
Other cloud
On-premises
Azure
Other cloud
On-premises
Operating systems Windows
Linux
Windows
Linux
Windows
Linux
Agent dependencies None None Requires Log Analytics agent
Data collected Event Logs
ETW events
Syslog
Performance
IIS logs
.NET app tracing output logs
Crash dumps
Event Logs
Syslog
Performance
IIS logs
Custom logs
Data from solutions
Process details and dependencies
Network connection metrics
Data sent to Azure Storage
Azure Monitor Metrics
Event Hub
Azure Monitor Logs Azure Monitor Logs

Azure Diagnostic extension

The Azure Diagnostics extension collects monitoring data from the guest operating system and workloads of Azure compute resources. It primarily collects data into Azure Storage. You can configure Azure Monitor to copy the data from storage to a Log Analytics workspace. You can also collect guest performance data into Azure Monitor Metrics.

Azure Diagnostic Extension is often referred to as the Windows Azure Diagnostic (WAD) or Linux Azure Diagnostic (LAD) extension.

Scenarios supported

Scenarios supported by the Azure Diagnostics extension include the following:

Log Analytics agent

The Log Analytics agent collects monitoring data from the guest operating system and workloads of virtual machines in Azure, other cloud providers, and on-premises. It collects data into a Log Analytics workspace.

The Log Analytics agent is the same agent used by System Center Operations Manager, and you multihome agent computers to communicate with your management group and Azure Monitor simultaneously. This agent is also required by certain solutions in Azure Monitor.

The Log Analytics agent for Windows is often referred to as Microsoft Management Agent (MMA). The Log Analytics agent for Linux is often referred to as OMS agent.

Scenarios supported

Scenarios supported by the Log Analytics agent include the following:

Dependency agent

The Dependency agent collects discovered data about processes running on the virtual machine and external process dependencies. This agent is required for Service Map and the Map feature Azure Monitor for VMs. The Dependency agent requires the Log Analytics agent and writes data to a Log Analytics workspace in Azure Monitor.

Using multiple agents

You may have specific requirements to use either the Azure Diagnostic Extension or Log Analytics agent for a particular virtual machine. For example, you may want to use metric alerts which requires Azure Diagnostic Extension. But you may also want to use the Map feature of Azure Monitor for VMs which requires the Dependency agent and the Log Analytics agent. In this case, you can use multiple agents, and this is a common scenario for customers who require functionality from each.

Considerations

  • The Dependency agent requires the Log Analytics agent to be installed on the same virtual machine.
  • On Linux VMs, the Log Analytics agent must be installed before the Azure Diagnostic Extension.

Next steps

  • See Overview of the Log Analytics agent to review requirements and supported methods to deploy the agent to machines hosted in Azure, in your datacenter, or other cloud environment.