Configuring Managed Identity for Azure Functions involves using either System Assigned Managed Identity or User Assigned Managed Identity. Here's how you can set up both types:
Enabling System Assigned Managed Identity
1. Navigate to Azure Portal: Go to your Azure Function App in the Azure portal.
2. Select Identity Option: In the left menu, select Settings and then click on Identity.
3. Enable System Assigned Identity: On the System assigned tab, toggle the status to On and click Save. This creates a managed identity with the same name as your function app.
4. Assign Permissions: Navigate to the resource (e.g., Azure Storage or SQL Database) you want your function to access. Assign the appropriate roles to the managed identity by going to Access Control (IAM), then Role assignments, and adding the managed identity to the required roles[1][3][7].
Enabling User Assigned Managed Identity
1. Create a User Assigned Identity: First, create a user-assigned managed identity resource in Azure. This identity can be used across multiple resources.
2. Assign to Function App: In the Azure portal, navigate to your Function App's Identity settings. Switch to the User assigned tab and click Add. Search for and select the user-assigned identity you created[1][6].
3. Configure App Settings: For certain services like Key Vault, you might need to set additional properties (e.g., `keyVaultReferenceIdentity`) via REST API calls, as these settings are not available in the UI[1].
4. Assign Permissions: Similar to system-assigned identities, assign the necessary roles to the user-assigned identity for the target resources[6].
Using Managed Identity in Code
When using managed identities, your Azure Functions can leverage libraries like `Azure.Identity` to authenticate with Azure services without handling secrets directly. For example, you can use `DefaultAzureCredential` to connect to Azure Storage or SQL Database[5][9].
Benefits of Managed Identities
- Security: Avoids the need to store secrets in code or configuration files.
- Flexibility: Allows for easy management of access permissions via Azure RBAC.
- Scalability: Supports both system-assigned and user-assigned identities for different scenarios[4][6].
Citations:
[1] https://www.red-gate.com/simple-talk/cloud/azure/azure-function-and-user-assigned-managed-identities/
[2] https://codebankblog.wordpress.com/2020/06/27/azure-function-with-managed-identity-and-azure-sql-db/
[3] https://kumarashwinhubert.com/secure-your-azure-functions-use-managed-identity-for-azurewebjobsstorage
[4] https://docs.azure.cn/en-us/azure-functions/functions-identity-based-connections-tutorial
[5] https://www.linkedin.com/pulse/how-use-managed-identities-app-service-azure-ali-khan-
[6] https://learn.microsoft.com/en-us/azure/app-service/overview-managed-identity
[7] https://docs.azure.cn/en-us/azure-functions/functions-identity-access-azure-sql-with-managed-identity
[8] https://learn.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-configure-managed-identity
[9] https://www.transparity.com/app-innovation/azure-functions-with-managed-identity-storage-access/