Use managed identities for App Service and Azure Functions

1. In the Azure portal, go to your app's page.

2. On the left menu, select Settings > Identity.

3. On the System assigned tab, switch Status to On. Then select Save.

Run the az webapp identity assign command:

az webapp identity assign --resource-group <group-name> --name <app-name> 

Run the Set-AzWebApp -AssignIdentity command:

Set-AzWebApp -AssignIdentity $true -ResourceGroupName <group-name>  -Name <app-name>

Run the Update-AzFunctionApp -IdentityType command:

Update-AzFunctionApp -ResourceGroupName <group-name> -Name <function-app-name>  -IdentityType SystemAssigned

You can use an Azure Resource Manager template to automate deployment of your Azure resources. To learn more, see Automate resource deployment in App Service and Automate resource deployment in Azure Functions.

You can create any resource of type Microsoft.Web/sites with an identity by including the following property in the resource definition:

"identity": {
    "type": "SystemAssigned"
}

Adding the system-assigned type tells Azure to create and manage the identity for your application.

For example, a web app's template might look like the following JSON:

{
    "apiVersion": "2022-03-01",
    "type": "Microsoft.Web/sites",
    "name": "[variables('appName')]",
    "location": "[resourceGroup().location]",
    "identity": {
        "type": "SystemAssigned"
    },
    "properties": {
        "name": "[variables('appName')]",
        "serverFarmId": "[resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName'))]",
        "hostingEnvironment": "",
        "clientAffinityEnabled": false,
        "alwaysOn": true
    },
    "dependsOn": [
        "[resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName'))]"
    ]
}

When the site is created, it includes the following properties:

"identity": {
    "type": "SystemAssigned",
    "tenantId": "<tenant-id>",
    "principalId": "<principal-id>"
}

The tenantId property identifies what Microsoft Entra tenant the identity belongs to. The principalId property is a unique identifier for the application's new identity. In Microsoft Entra ID, the service principal has the same name that you gave to your App Service or Azure Functions instance.

If you need to refer to these properties in a later stage in the template, use the reference() template function with the 'Full' option, as in this example:

{
    "tenantId": "[reference(resourceId('Microsoft.Web/sites', variables('appName')), '2018-02-01', 'Full').identity.tenantId]",
    "objectId": "[reference(resourceId('Microsoft.Web/sites', variables('appName')), '2018-02-01', 'Full').identity.principalId]",
}

1. Create a user-assigned managed identity resource according to these instructions.

2. On the left menu for your app's page, select Settings > Identity.

3. Select User assigned, then select Add.

4. Search for the identity that you created earlier, select it, and then select Add.

After you finish these steps, the app restarts.

1. Create a user-assigned identity:

   az identity create --resource-group <group-name> --name <identity-name>
   

2. Run the az webapp identity assign command to assign the identity to the app:

   az webapp identity assign --resource-group <group-name> --name <app-name> --identities <identity-id>
   

Adding a user-assigned identity in App Service by using Azure PowerShell is currently not supported.

1. Create a user-assigned identity:

   Install-Module -Name Az.ManagedServiceIdentity -AllowPrerelease
   $userAssignedIdentity = New-AzUserAssignedIdentity -Name <identity-name> -ResourceGroupName <group-name> -Location <region>
   

2. Run the Update-AzFunctionApp -IdentityType UserAssigned -IdentityId command to assign the identity in Functions:

   Update-AzFunctionApp -Name <app-name> -ResourceGroupName <group-name> -IdentityType UserAssigned -IdentityId $userAssignedIdentity.Id
   

You can use an Azure Resource Manager template to automate deployment of your Azure resources. To learn more, see Automate resource deployment in App Service and Automate resource deployment in Azure Functions.

You can create any resource of type Microsoft.Web/sites with an identity by including the following block in the resource definition. Replace <resource-id> with the resource ID of the desired identity.

"identity": {
    "type": "UserAssigned",
    "userAssignedIdentities": {
        "<resource-id>": {}
    }
}

Adding the user-assigned type tells Azure to use the user-assigned identity that you specified for your application.

For example, a web app's template might look like the following JSON:

{
    "apiVersion": "2022-03-01",
    "type": "Microsoft.Web/sites",
    "name": "[variables('appName')]",
    "location": "[resourceGroup().location]",
    "identity": {
        "type": "UserAssigned",
        "userAssignedIdentities": {
            "[resourceId('Microsoft.ManagedIdentity/userAssignedIdentities', variables('identityName'))]": {}
        }
    },
    "properties": {
        "name": "[variables('appName')]",
        "serverFarmId": "[resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName'))]",
        "hostingEnvironment": "",
        "clientAffinityEnabled": false,
        "alwaysOn": true
    },
    "dependsOn": [
        "[resourceId('Microsoft.Web/serverfarms', variables('hostingPlanName'))]",
        "[resourceId('Microsoft.ManagedIdentity/userAssignedIdentities', variables('identityName'))]"
    ]
}

When the site is created, it includes the following properties:

"identity": {
    "type": "UserAssigned",
    "userAssignedIdentities": {
        "<resource-id>": {
            "principalId": "<principal-id>",
            "clientId": "<client-id>"
        }
    }
}

The principalId property is a unique identifier for the identity that's used for Microsoft Entra administration. The clientId property is a unique identifier for the application's new identity. You use it to specify which identity to use during runtime calls.

A raw HTTP GET request uses the two supplied environment variables and looks like the following example:

GET /MSI/token?resource=https://vault.azure.cn&api-version=2019-08-01 HTTP/1.1
Host: <ip-address-:-port-in-IDENTITY_ENDPOINT>
X-IDENTITY-HEADER: <value-of-IDENTITY_HEADER>

A sample response might look like the following example:

HTTP/1.1 200 OK
Content-Type: application/json

{
    "access_token": "eyJ0eXAi…",
    "expires_on": "1586984735",
    "resource": "https://vault.azure.cn",
    "token_type": "Bearer",
    "client_id": "00001111-aaaa-2222-bbbb-3333cccc4444"
}

This response is the same as the response for the Microsoft Entra service-to-service access token request. To access Key Vault, add the value of access_token to a client connection with the vault.

For .NET apps and functions, the simplest way to work with a managed identity is through the Azure Identity client library for .NET. For more information, see Tutorial: Connect to Azure databases from App Service without secrets by using a managed identity.

For more information, see the respective documentation headings of the client library:

• Add the Azure Identity client library to your project
• Access an Azure service by using a system-assigned identity
• Access an Azure service by using a user-assigned identity

The linked examples use DefaultAzureCredential. The same pattern works in Azure with managed identities and on your local machine without managed identities.

For Node.js apps and JavaScript functions, the simplest way to work with a managed identity is through the Azure Identity client library for JavaScript. For more information, see Tutorial: Connect to Azure databases from App Service without secrets by using a managed identity.

For more information, see the respective documentation headings of the client library:

• Add an Azure Identity client library to your project
• Access an Azure service by using a system-assigned identity
• Access an Azure service by using a user-assigned identity

The linked examples use DefaultAzureCredential. The same pattern works in Azure with managed identities and on your local machine without managed identities.

For more code examples of the Azure Identity client library for JavaScript, see Azure Identity examples.

For Python apps and functions, the simplest way to work with a managed identity is through the Azure Identity client library for Python. For more information, see Tutorial: Connect to Azure databases from App Service without secrets by using a managed identity.

For more information, see the respective documentation headings of the client library:

• Add an Azure Identity client library to your project
• Access an Azure service by using a system-assigned identity
• Access an Azure service by using a user-assigned identity

The linked examples use DefaultAzureCredential. The same pattern works in Azure with managed identities and on your local machine without managed identities.

For Java apps and functions, the simplest way to work with a managed identity is through the Azure Identity client library for Java. For more information, see Tutorial: Connect to Azure databases from App Service without secrets by using a managed identity.

For more information, see the respective documentation headings of the client library:

• Add an Azure Identity client library to your project
• Access an Azure service by using a system-assigned identity
• Access an Azure service by using a user-assigned identity

The linked examples use DefaultAzureCredential. The same pattern works in Azure with managed identities and on your local machine without managed identities.

For more code examples of the Azure Identity client library for Java, see Azure Identity examples.

Use the following script to retrieve a token from the local endpoint by specifying a resource URI of an Azure service:

$resourceURI = "https://<Entra-resource-URI-for-resource-to-obtain-token>"
$tokenAuthURI = $env:IDENTITY_ENDPOINT + "?resource=$resourceURI&api-version=2019-08-01"
$tokenResponse = Invoke-RestMethod -Method Get -Headers @{"X-IDENTITY-HEADER"="$env:IDENTITY_HEADER"} -Uri $tokenAuthURI
$accessToken = $tokenResponse.access_token

1. On the left menu for your app's page, select Settings > Identity.

2. Follow the steps based on the identity type:

   • For a system-assigned identity: On the System assigned tab, switch Status to Off. Then select Save.
   • For a user-assigned identity: Select the User assigned tab, select the checkbox for the identity, and then select Remove. Select Yes to confirm.

To remove the system-assigned identity, use this command:

az webapp identity remove --resource-group <group-name> --name <app-name>

To remove one or more user-assigned identities, use this command:

az webapp identity remove --resource-group <group-name> --name <app-name> --identities <identity-id1> <identity-id2> ...

You can also remove the system-assigned identity by specifying [system] in --identities.

To remove a system-assigned identity for App Service, run the Set-AzWebApp -AssignIdentity command:

Set-AzWebApp -AssignIdentity $false -Name <app-name> -ResourceGroupName <group-name> 

To remove all identities in Azure PowerShell (Azure Functions only), run this command:

# Update an existing function app to have IdentityType "None".
Update-AzFunctionApp -Name <function-app-name> -ResourceGroupName <group-name> -IdentityType None

To remove all identities in an ARM template, use this code:

"identity": {
    "type": "None"
}