Create diagnostic settings in Azure Monitor

Create and edit diagnostic settings in Azure Monitor to send Azure platform metrics and logs to different destinations like Azure Monitor Logs, Azure Storage, or Azure Event Hubs. You can use different methods to work with the diagnostic settings, such as the Azure portal, the Azure CLI, PowerShell, and Azure Resource Manager.

Important

The Retention Policy as set in the Diagnostic Setting settings is now deprecated and can no longer be used. Use the Azure Storage Lifecycle Policy to manage the length of time that your logs are retained. For more information, see Migrate diagnostic settings storage retention to Azure Storage lifecycle management

Azure portal

You can configure diagnostic settings in the Azure portal either from the Azure Monitor menu or from the menu for the resource.

1. Where you configure diagnostic settings in the Azure portal depends on the resource:

   • For a single resource, select Diagnostic settings under Monitoring on the resource's menu.

     

   • For one or more resources, select Diagnostic settings under Settings on the Azure Monitor menu and then select the resource.

     

   • For the activity log, select Activity log on the Azure Monitor menu and then select Export Activity Logs. Make sure you disable any legacy configuration for the activity log. For instructions, see Disable existing settings.

     

2. If no settings exist on the resource you select, you're prompted to create a setting. Select Add diagnostic setting.

   

   If there are existing settings on the resource, you see a list of settings already configured. Select Add diagnostic setting to add a new setting. Or select Edit setting to edit an existing one. Each setting can have no more than one of each of the destination types.

   

3. Give your setting a name if it doesn't already have one.

   

4. Logs and metrics to route: For logs, either choose a category group or select the individual checkboxes for each category of data you want to send to the destinations specified later. The list of categories varies for each Azure service. Select AllMetrics if you want to store metrics in Azure Monitor Logs too.

5. Destination details: Select the checkbox for each destination. Options appear so that you can add more information.

   

   1. Send to Log Analytics workspace: Select your Subscription and the Log Analytics workspace where you want to send the data. If you don't have a workspace, you must create one before you proceed.

   2. Archive to a storage account: Select your Subscription and the Storage account where you want to store the data.

      

      Tip

      Use the Azure Storage Lifecycle Policy to manage the length of time that your logs are retained. The Retention Policy as set in the Diagnostic Setting settings is now deprecated.

   3. Stream to an event hub: Specify the following criteria:

      • Subscription: The subscription that the event hub is part of.
      • Event hub namespace: If you don't have one, you must create one.
      • Event hub name (optional): The name to send all data to. If you don't specify a name, an event hub is created for each log category. If you're sending to multiple categories, you might want to specify a name to limit the number of event hubs created. For more information, see Azure Event Hubs quotas and limits.
      • Event hub policy name (also optional): A policy defines the permissions that the streaming mechanism has. For more information, see Event Hubs features.

   4. Send to partner solution: You must first install Azure Native ISV Services into your subscription. Configuration options vary by partner. For more information, see Azure Native ISV Services overview.

6. If the service supports both resource-specific and Azure diagnostics mode, then an option to select the destination table displays when you select Log Analytics workspace as a destination. You should usually select Resource specific since the table structure allows for more flexibility and more efficient queries.

   

7. Select Save.

After a few moments, the new setting appears in your list of settings for this resource. Logs are streamed to the specified destinations as new event data is generated. It might take up to 15 minutes between when an event is emitted and when it appears in a Log Analytics workspace.

PowerShell

Use the New-AzDiagnosticSetting cmdlet to create a diagnostic setting with Azure PowerShell. See the documentation for this cmdlet for descriptions of its parameters.

Important

You can't use this method for an activity log. Instead, use Create diagnostic setting in Azure Monitor by using an Azure Resource Manager template to create a Resource Manager template and deploy it with PowerShell.

The following example PowerShell cmdlet creates a diagnostic setting for all logs, or for audit logs, and metrics for a key vault by using Log Analytics Workspace.

$KV = Get-AzKeyVault -ResourceGroupName <resource group name> -VaultName <key vault name>
$Law = Get-AzOperationalInsightsWorkspace -ResourceGroupName <resource group name> -Name <workspace name>  # LAW name is case sensitive

$metric = New-AzDiagnosticSettingMetricSettingsObject -Enabled $true -Category AllMetrics
# For all available logs, use:
$log = New-AzDiagnosticSettingLogSettingsObject -Enabled $true -CategoryGroup allLogs  
# or, for audit logs, use:
$log = New-AzDiagnosticSettingLogSettingsObject -Enabled $true -CategoryGroup audit    
New-AzDiagnosticSetting -Name 'KeyVault-Diagnostics' -ResourceId $KV.ResourceId -WorkspaceId $Law.ResourceId -Log $log -Metric $metric -Verbose

CLI

Use the az monitor diagnostic-settings create command to create a diagnostic setting with the Azure CLI. See the documentation for this command for descriptions of its parameters.

Important

You can't use this method for an activity log. Instead, use Create diagnostic setting in Azure Monitor by using a Resource Manager template to create a Resource Manager template and deploy it with the Azure CLI.

The following example command creates a diagnostic setting by using all three destinations. The syntax is slightly different depending on your client.

To specify resource-specific mode if the service supports it, add the export-to-resource-specific parameter with a value of true.`

az monitor diagnostic-settings create  \
--name KeyVault-Diagnostics \
--resource /subscriptions/<subscription ID>/resourceGroups/<resource group name>/providers/Microsoft.KeyVault/vaults/mykeyvault \
--logs    '[{"category": "AuditEvent","enabled": true}]' \
--metrics '[{"category": "AllMetrics","enabled": true}]' \
--storage-account /subscriptions/<subscription ID>/resourceGroups/<resource group name>/providers/Microsoft.Storage/storageAccounts/<storage account name> \
--workspace /subscriptions/<subscription ID>/resourcegroups/<resource group name>/providers/microsoft.operationalinsights/workspaces/<log analytics workspace name> \
--event-hub-rule /subscriptions/<subscription ID>/resourceGroups/<resource group name>/providers/Microsoft.EventHub/namespaces/<event hub namespace>/authorizationrules/RootManageSharedAccessKey \
--event-hub <event hub name> \
--export-to-resource-specific true

Resource Manager

The following JSON template provides an example for creating a diagnostic setting to send all audit logs to a log analytics workspace. Keep in mind that the apiVersion can change depending on the resource in the scope.

Template file

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "scope": {
        "type": "string"
    },
    "workspaceId": {
        "type": "string"
    },
    "settingName": {
        "type": "string"
    }
},
  "resources": [
    {
      "type": "Microsoft.Insights/diagnosticSettings",
      "apiVersion": "2021-05-01-preview",
      "scope": "[parameters('scope')]",
      "name": "[parameters('settingName')]",
      "properties": {
       "workspaceId": "[parameters('workspaceId')]",
      "logs": [
             {
            "category": null,
            "categoryGroup": "audit",
            "enabled": true
          }
        ]
      }
    }
  ]
  }

Parameter file

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "settingName": {
        "value": "audit3"
    },
    "workspaceId": {
      "value": "/subscriptions/<subscription id>/resourcegroups/<resourcegroup name>/providers/microsoft.operationalinsights/workspaces/<workspace name>"
    },
    "scope": {
      "value": "Microsoft.<resource type>/<resourceName>"
    }
  }
}

REST API

To create or update diagnostic settings by using the Azure Monitor REST API, see Diagnostic settings.

Azure Policy

For details on using Azure Policy to create diagnostic settings at scale, see Create diagnostic settings at scale by using Azure Policy.

Troubleshooting

Here are some troubleshooting tips.

Metric category isn't supported

When you deploy a diagnostic setting, you receive an error message similar to "Metric category 'xxxx' isn't supported." You might receive this error even though your previous deployment succeeded.

The problem occurs when you use a Resource Manager template, REST API, the CLI, or Azure PowerShell. Diagnostic settings created via the Azure portal aren't affected because only the supported category names are presented.

The problem occurs because of a recent change in the underlying API. Metric categories other than AllMetrics aren't supported and never were except for a few specific Azure services. In the past, other category names were ignored when deploying a diagnostic setting. The Azure Monitor back end redirected these categories to AllMetrics. As of February 2021, the back end was updated to specifically confirm the metric category provided is accurate. This change can cause some deployments to fail.

If you receive this error, update your deployments to replace any metric category names with AllMetrics to fix the issue. If the deployment was previously adding multiple categories, only keep one with the AllMetrics reference. If you continue to have the problem, contact Azure support through the Azure portal.

Setting disappears because of non-ASCII characters in resourceID

Diagnostic settings don't support resource IDs with non-ASCII characters. For example, consider the term "Preproducción." Because you can't rename resources in Azure, your only option is to create a new resource without the non-ASCII characters. If the characters are in a resource group, you can move the resources under it to a new one. Otherwise, you need to re-create the resource.

Possibility of duplicated or dropped data

Every effort is made to ensure all log data is sent correctly to your destinations, however it's not possible to guarantee 100% data transfer of logs between endpoints. Retries and other mechanisms are in place to work around these issues and attempt to ensure log data arrives at the endpoint.

Inactive resources

When a resource is inactive and exporting zero-value metrics, the diagnostic settings export mechanism backs off incrementally to avoid unnecessary costs of exporting and storing zero values. The back-off may lead to a delay in the export of the next non-zero value.

When a resource is inactive for one hour, the export mechanism backs off to 15 minutes. This means that there is a potential latency of up to 15 minutes for the next nonzero value to be exported. The maximum backoff time of two hours is reached after seven days of inactivity. Once the resource starts exporting nonzero values, the export mechanism reverts to the original export latency of three minutes.

This behavior only applies to exported metrics and doesn't affect metrics-based alerts or autosacle.

Next steps

• Review how to work with diagnostic settings in Azure Monitor
• Migrate diagnostic settings storage retention to Azure Storage lifecycle management
• Read more about Azure platform logs