Azure Monitor agent requirements

Article
07/15/2024

This article provides requirements and prerequisites for the Azure Monitor agent. Refer to the details in this article before you follow the guidance to install the agent in Install and manage Azure Monitor Agent.

Virtual machine extension details

Azure Monitor Agent is implemented as an Azure VM extension with the details in the following table. You can install it by using any of the methods to install virtual machine extensions. For version information, see Azure Monitor agent extension versions.

Property	Windows	Linux
Publisher	Microsoft.Azure.Monitor	Microsoft.Azure.Monitor
Type	AzureMonitorWindowsAgent	AzureMonitorLinuxAgent
TypeHandlerVersion	See Azure Monitor agent extension versions	Azure Monitor agent extension versions

Permissions

For methods other than using the Azure portal, you must have the following role assignments to install the agent:

Built-in role	Scopes	Reason
Virtual Machine Contributor Azure Connected Machine Resource Administrator	Virtual machines, scale sets, Azure Arc-enabled servers	To deploy the agent
Any role that includes the action Microsoft.Resources/deployments/* (for example, Log Analytics Contributor	Subscription and/or Resource group and/or	To deploy agent extension via Azure Resource Manager templates (also used by Azure Policy)

Managed identity must be enabled on Azure virtual machines. Both user-assigned and system-assigned managed identities are supported.

User-assigned: This managed identity should be used for large-scale deployments and can be configured with built-in Azure policies. You can create a user-assigned managed identity once and share it across multiple VMs making it more scalable than a system-assigned managed identity. If you use a user-assigned managed identity, you must pass the managed identity details to Azure Monitor Agent via extension settings:
```
{
    "authentication": {
    "managedIdentity": {
        "identifier-name": "mi_res_id" or "object_id" or "client_id",
        "identifier-value": "<resource-id-of-uai>" or "<guid-object-or-client-id>"
    }
    }
}
```

You should use mi_res_id as the identifier-name. The following sample commands only show usage with mi_res_id for the sake of brevity. For more information on mi_res_id, object_id, and client_id, see the Managed identity documentation.

System-assigned: This managed identity is suited for initial testing or small deployments. When used at scale, for all VMs in a subscription for example, it results in a substantial number of identities created and deleted in Microsoft Entra ID. To avoid this churn of identities, use user-assigned managed identities instead.

Important

System-assigned managed identity is the only supported authentication For Azure Arc-enabled servers and is enabled automatically as soon as you install the Azure Arc agent.

Disk space

Required disk space can vary significantly depending on how an agent is configured or if the agent is unable to communicate with the destinations and must cache data. By default the agent requires 10Gb of disk space to run. The following table provides guidance for capacity planning:

Purpose	Environment	Path	Suggested Space
Download and install packages	Linux	/var/lib/waagent/Microsoft.Azure.Monitor.AzureMonitorLinuxAgent-{Version}/	500 MB
Download and install packages	Windows	C:\Packages\Plugins\Microsoft.Azure.Monitor.AzureMonitorWindowsAgent	500 MB
Extension Logs	Linux (Azure VM)	/var/log/azure/Microsoft.Azure.Monitor.AzureMonitorLinuxAgent/	100 MB
Extension Logs	Linux (Azure Arc)	/var/lib/GuestConfig/extension_logs/Microsoft.Azure.Monitor.AzureMonitorLinuxAgent-{version}/	100 MB
Extension Logs	Windows (Azure VM)	C:\WindowsAzure\Logs\Plugins\Microsoft.Azure.Monitor.AzureMonitorWindowsAgent	100 MB
Extension Logs	Windows (Azure Arc)	C:\ProgramData\GuestConfig\extension_logs\Microsoft.Azure.Monitor.AzureMonitorWindowsAgent	100 MB
Agent Cache	Linux	/etc/opt/microsoft/azuremonitoragent, /var/opt/microsoft/azuremonitoragent	500 MB
Agent Cache	Windows (Azure VM)	C:\WindowsAzure\Resources\AMADataStore.{DataStoreName}	10.5 GB
Agent Cache	Windows (Azure Arc)	C:\Resources\Directory\AMADataStore. {DataStoreName}	10.5 GB
Event Cache	Linux	/var/opt/microsoft/azuremonitoragent/events	10 GB
Event Cache	Linux	/var/lib/rsyslog	1 GB

Next steps

Create a data collection rule to collect data from the agent and send it to Azure Monitor.

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