Query data across Log Analytics workspaces, applications, and resources in Azure Monitor
There are two ways to query data from multiple workspaces, applications, and resources:
- Explicitly by specifying the workspace, app, or resource information using the workspace(), app(), or resource() expressions, as described in this article.
- Implicitly by using resource-context queries. When you query in the context of a specific resource, resource group, or a subscription, the query retrieves relevant data from all workspaces that contain data for these resources. Resource-context queries don't retrieve data from classic Application Insights resources.
This article explains how to use the workspace(), app(), and resource() expressions to query data from multiple Log Analytics workspaces, applications, and resources.
If you manage subscriptions in other Microsoft Entra tenants through Azure Lighthouse, you can include Log Analytics workspaces created in those customer tenants in your queries.
Important
If you're using a workspace-based Application Insights resource, telemetry is stored in a Log Analytics workspace with all other log data. Use the workspace() expression to query data from applications in multiple workspaces. You don't need a cross-workspace query to query data from multiple applications in the same workspace.
Permissions required
- You must have
Microsoft.OperationalInsights/workspaces/query/*/readpermissions to the Log Analytics workspaces you query, as provided by the Log Analytics Reader built-in role, for example. - To save a query, you must have
microsoft.operationalinsights/querypacks/queries/actionpermisisons to the query pack where you want to save the query, as provided by the Log Analytics Contributor built-in role, for example.
Limitations
- Cross-resource and cross-service queries don’t support parameterized functions and functions whose definition includes other cross-workspace or cross-service expressions, including
adx(),arg(),resource(),workspace(), andapp(). - You can include up to 100 Log Analytics workspaces or classic Application Insights resources in a single query.
- Querying across a large number of resources can substantially slow down the query.
- Cross-resource queries in log alerts are only supported in the current scheduledQueryRules API. If you're using the legacy Log Analytics Alerts API, you'll need to switch to the current API.
- References to a cross resource, such as another workspace, should be explicit and can't be parameterized.
Query across workspaces, applications, and resources using functions
This section explains how to query workspaces, applications, and resources using functions with and without using a function.
Query without using a function
You can query multiple resources from any of your resource instances. These resources can be workspaces and apps combined.
Example for a query across three workspaces:
union
Update,
workspace("00000000-0000-0000-0000-000000000001").Update,
workspace("00000000-0000-0000-0000-000000000002").Update
| where TimeGenerated >= ago(1h)
| where UpdateState == "Needed"
| summarize dcount(Computer) by Classification
For more information on the union, where, and summarize operators, see union operator, where operator, and summarize operator.
Query by using a function
When you use cross-resource queries to correlate data from multiple Log Analytics workspaces and Application Insights components, the query can become complex and difficult to maintain. You should make use of functions in Azure Monitor log queries to separate the query logic from the scoping of the query resources. This method simplifies the query structure. The following example demonstrates how you can monitor multiple Application Insights components and visualize the count of failed requests by application name.
Create a query like the following example that references the scope of Application Insights components. The withsource= SourceApp command adds a column that designates the application name that sent the log. Save the query as a function with the alias applicationsScoping.
// crossResource function that scopes my Application Insights components
union withsource= SourceApp
app('00000000-0000-0000-0000-000000000000').requests,
app('00000000-0000-0000-0000-000000000001').requests,
app('00000000-0000-0000-0000-000000000002').requests,
app('00000000-0000-0000-0000-000000000003').requests,
app('00000000-0000-0000-0000-000000000004').requests
You can now use this function in a cross-resource query like the following example. The function alias applicationsScoping returns the union of the requests table from all the defined applications. The query then filters for failed requests and visualizes the trends by application. The parse operator is optional in this example. It extracts the application name from the SourceApp property.
applicationsScoping
| where timestamp > ago(12h)
| where success == 'False'
| parse SourceApp with * '(' applicationId ')' *
| summarize count() by applicationId, bin(timestamp, 1h)
| render timechart
Note
This method can't be used with log alerts because the access validation of the alert rule resources, including workspaces and applications, is performed at alert creation time. Adding new resources to the function after the alert creation isn't supported. If you prefer to use a function for resource scoping in log alerts, you must edit the alert rule in the portal or with an Azure Resource Manager template to update the scoped resources. Alternatively, you can include the list of resources in the log alert query.
Query across Log Analytics workspaces using workspace()
Use the workspace() expression to retrieve data from a specific workspace in the same resource group, another resource group, or another subscription. You can use this expression to include log data in an Application Insights query and to query data across multiple workspaces in a log query.
Syntax
workspace(Identifier)
Arguments
*Identifier*: Identifies the workspace by using one of the formats in the following table.
| Identifier | Description | Example |
|---|---|---|
| ID | GUID of the workspace | workspace("00000000-0000-0000-0000-000000000000") |
| Azure Resource ID | Identifier for the Azure resource | workspace("/subscriptions/00000000-0000-0000-0000-000000000000/resourcegroups/Contoso/providers/Microsoft.OperationalInsights/workspaces/contosoretail") |
Examples
workspace("00000000-0000-0000-0000-000000000000").Update | count
workspace("/subscriptions/00000000-0000-0000-0000-000000000000/resourcegroups/Contoso/providers/Microsoft.OperationalInsights/workspaces/contosoretail").Event | count
union
( workspace("00000000-0000-0000-0000-000000000000").Heartbeat | where Computer == "myComputer"),
(app("00000000-0000-0000-0000-000000000000").requests | where cloud_RoleInstance == "myRoleInstance")
| count
union
(workspace("00000000-0000-0000-0000-000000000000").Heartbeat), (app("00000000-0000-0000-0000-000000000000").requests) | where TimeGenerated between(todatetime("2023-03-08 15:00:00") .. todatetime("2023-04-08 15:05:00"))
Query across classic Application Insights applications using app()
Use the app expression to retrieve data from a specific classic Application Insights resource in the same resource group, another resource group, or another subscription. If you're using a workspace-based Application Insights resource, telemetry is stored in a Log Analytics workspace with all other log data. Use the workspace() expression to query data from applications in multiple workspaces. You don't need a cross-workspace query to query data from multiple applications in the same workspace.
Syntax
app(Identifier)
Arguments
*Identifier*: Identifies the app using one of the formats in the table below.
| Identifier | Description | Example |
|---|---|---|
| ID | GUID of the app | app("00000000-0000-0000-0000-000000000000") |
| Azure Resource ID | Identifier for the Azure resource | app("/subscriptions/00000000-0000-0000-0000-000000000000/resourcegroups/Fabrikam/providers/microsoft.insights/components/fabrikamapp") |
Examples
app("00000000-0000-0000-0000-000000000000").requests | count
app("/subscriptions/00000000-0000-0000-0000-000000000000/resourcegroups/Fabrikam/providers/microsoft.insights/components/fabrikamapp").requests | count
union
(workspace("00000000-0000-0000-0000-000000000000").Heartbeat | where Computer == "myComputer"),
(app("00000000-0000-0000-0000-000000000000").requests | where cloud_RoleInstance == "myColumnInstance")
| count
union
(workspace("00000000-0000-0000-0000-000000000000").Heartbeat), (app("00000000-0000-0000-0000-000000000000").requests)
| where TimeGenerated between(todatetime("2023-03-08 15:00:00") .. todatetime("2023-04-08 15:05:00"))
Correlate data between resources using resource()
The resource expression is used in a Azure Monitor query scoped to a resource to retrieve data from other resources.
Syntax
resource(Identifier)
Arguments
*Identifier*: Identifies the resource, resource group, or subscription from which to correlate data.
| Identifier | Description | Example |
|---|---|---|
| Resource | Includes data for the resource. | resource("/subscriptions/xxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourcesgroups/myresourcegroup/providers/microsoft.compute/virtualmachines/myvm") |
| Resource Group or Subscription | Includes data for the resource and all resources that it contains. | resource("/subscriptions/xxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourcesgroups/myresourcegroup) |
Examples
union (Heartbeat),(resource("/subscriptions/xxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourcesgroups/myresourcegroup/providers/microsoft.compute/virtualmachines/myvm").Heartbeat) | summarize count() by _ResourceId, TenantId
union (Heartbeat),(resource("/subscriptions/xxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx/resourcesgroups/myresourcegroup).Heartbeat) | summarize count() by _ResourceId, TenantId
Next steps
See Analyze log data in Azure Monitor for an overview of log queries and how Azure Monitor log data is structured.
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