managed_identity.md

Back to Chat with your data README

Overview

Chat with Your Data authenticates to Azure with a single user-assigned managed identity. Every service the workload calls is authorized through Azure role-based access control (RBAC) rather than connection strings or keys. There is no Key Vault and there are no application secrets to store or rotate.

One identity for the workload

The deployment creates one user-assigned managed identity and attaches it to the backend, the frontend, and the ingestion worker. Each Container App pulls its image and calls downstream services as that identity, so access is granted once and applies consistently across the three services. The following diagram shows the three services assuming the shared identity, which carries the least-privilege RBAC roles on each downstream Azure service.

flowchart LR
    Backend["Backend Container App"]
    Frontend["Frontend Container App"]
    Worker["Ingestion worker Container App"]
    UAMI["User-assigned managed identity<br/>one per deployment"]
    RBAC["Least-privilege RBAC roles"]
    Foundry["Azure AI Foundry"]
    Index["Azure AI Search or PostgreSQL"]
    Storage["Azure Storage"]
    History["Cosmos DB or PostgreSQL"]
    Support["Content Safety, Speech,<br/>Container Registry, Event Grid"]

    Backend --> UAMI
    Frontend --> UAMI
    Worker --> UAMI
    UAMI --> RBAC
    RBAC --> Foundry
    RBAC --> Index
    RBAC --> Storage
    RBAC --> History
    RBAC --> Support

Role assignments

The deployment assigns the managed identity the least-privilege roles it needs on each resource.

Target	Access
Azure AI Foundry	Call chat, embedding, and retrieval models.
Azure AI Search	Read and write the retrieval index (cosmosdb mode).
PostgreSQL	Read and write the index and chat history (postgresql mode).
Azure Storage	Read and write ingestion blobs and send messages to the processing queues.
Azure Cosmos DB	Read and write chat history (cosmosdb mode).
Content Safety	Screen prompts and responses.
Speech	Mint short-lived speech tokens.
Container Registry	Pull the container images.
Event Grid	Send blob events to the ingestion queue.

No application secrets

Application configuration is passed to the Container Apps as environment variables, and access to data services is granted through RBAC. Because there are no keys or connection strings in the application configuration, there is no secret store to manage.

Optional hardening

The deployment supports optional security features that you can enable at deployment time.

• Private networking adds a virtual network, private DNS zones, and a bastion host so data-plane traffic stays off the public internet. Enable it with the enablePrivateNetworking parameter.
• Enable Microsoft Defender for Cloud on the subscription to monitor the deployed resources.
• Enable secret scanning on your repository fork to catch accidental credential commits.

Related documentation

• Architecture overview
• App authentication setup
• Customizing azd parameters