Connect to Azure Storage using a managed identity (Azure AI Search)

Artikel
06/05/2024

This article explains how to configure a search service connection to an Azure Storage account using a managed identity instead of providing credentials in the connection string.

You can use a system-assigned managed identity or a user-assigned managed identity. Managed identities are Microsoft Entra logins and require role assignments for access to Azure Storage.

Prerequisites

Azure AI Search, Basic tier or higher, with a managed identity.

Note

If storage is network-protected and in the same region as your search service, you must use a system-assigned managed identity and either one of the following network options: connect as a trusted service, or connect using the resource instance rule.

Create a role assignment in Azure Storage

Sign in to Azure portal and find your storage account.
Select Access control (IAM).
Select Add and then select Role assignment.

From the list of job function roles, select the roles needed for your search service:

Task	Role assignment
Blob indexing using an indexer	Add Storage Blob Data Reader
ADLS Gen2 indexing using an indexer	Add Storage Blob Data Reader
Table indexing using an indexer	Add Reader and Data Access
File indexing using an indexer	Add Reader and Data Access
Write to a knowledge store	Add Storage Blob DataContributor for object and file projections, and Reader and Data Access for table projections.
Write to an enrichment cache	Add Storage Blob Data Contributor
Save debug session state	Add Storage Blob Data Contributor

Select Next.
Select Managed identity and then select Members.
Filter by system-assigned managed identities or user-assigned managed identities. If you don't have a managed identity, see Configure search to use a managed identity. If you already set one up but it's not available, give it a few minutes.
Select the identity and save the role assignment.

Specify a managed identity in a connection string

Once you have a role assignment, you can set up a connection to Azure Storage that operates under that role.

Indexers use a data source object for connections to an external data source. This section explains how to specify a system-assigned managed identity or a user-assigned managed identity on a data source connection string. You can find more connection string examples in the managed identity article.

Tip

You can create a data source connection to Azure Storage in the Azure portal, specifying either a system or user-assigned managed identity, and then view the JSON definition to see how the connection string is formulated.

System-assigned managed identity

You must have a system-assigned managed identity already configured, and it must have a role-assignment on Azure Storage.

For connections made using a system-assigned managed identity, the only change to the data source definition is the format of the credentials property.

Provide a ResourceId that has no account key or password. The ResourceId must include the subscription ID of the storage account, the resource group of the storage account, and the storage account name.

POST https://[service name].search.windows.net/datasources?api-version=2023-11-01

{
    "name" : "blob-datasource",
    "type" : "azureblob",
    "credentials" : { 
        "connectionString" : "ResourceId=/subscriptions/00000000-0000-0000-0000-00000000/resourceGroups/MY-DEMO-RESOURCE-GROUP/providers/Microsoft.Storage/storageAccounts/MY-DEMO-STORAGE-ACCOUNT/;" 
    },
    "container" : { 
        "name" : "my-container", "query" : "<optional-virtual-directory-name>" 
    }
}

User-assigned managed identity

You must have a user-assigned managed identity already configured and associated with your search service, and the identity must have a role-assignment on Azure Storage.

Connections made through user-assigned managed identities use the same credentials as a system-assigned managed identity, plus an extra identity property that contains the collection of user-assigned managed identities. Only one user-assigned managed identity should be provided when creating the data source. Set userAssignedIdentity to the user-assigned managed identity..

Provide an identity using the syntax shown in the following example.

POST https://[service name].search.windows.net/datasources?api-version=2023-11-01

{
    "name" : "blob-datasource",
    "type" : "azureblob",
    "credentials" : { 
        "connectionString" : "ResourceId=/subscriptions/00000000-0000-0000-0000-00000000/resourceGroups/MY-DEMO-RESOURCE-GROUP/providers/Microsoft.Storage/storageAccounts/MY-DEMO-STORAGE-ACCOUNT/;" 
    },
    "container" : { 
        "name" : "my-container", "query" : "<optional-virtual-directory-name>" 
    },
    "identity" : { 
        "@odata.type": "#Microsoft.Azure.Search.DataUserAssignedIdentity",
        "userAssignedIdentity" : "/subscriptions/00000000-0000-0000-0000-00000000/resourcegroups/MY-DEMO-RESOURCE-GROUP/providers/Microsoft.ManagedIdentity/userAssignedIdentities/MY-DEMO-USER-MANAGED-IDENTITY" 
    }
}

Connection information and permissions on the remote service are validated at run time during indexer execution. If the indexer is successful, the connection syntax and role assignments are valid. For more information, see Run or reset indexers, skills, or documents.

Accessing network secured data in storage accounts

Azure storage accounts can be further secured using firewalls and virtual networks. If you want to index content from a storage account that is secured using a firewall or virtual network, see Make indexer connections to Azure Storage as a trusted service.

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