Deployment Stage Fails with DefaultAzureCredential Error – Authentication Succeeds

[Shiva3]

I’m a DevOps engineer automating CI/CD deployments to a Microsoft Fabric Dev/Test workspace using Azure DevOps. We are using a service principal (service account) for authentication.

✅ Authentication completes successfully, but during the deployment stage, we receive the following error:

DefaultAzureCredential failed to retrieve a token from the included credentials.

This happens when the deployment script (deploy.py) runs, even though the service principal is authenticated earlier in the pipeline.

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❓ What We Need

1. Why would DefaultAzureCredential fail during deployment even after successful authentication?
2. Are there any Fabric-specific configurations or SDK requirements we should be aware of?
3. Can you provide a working example or best practices for deploying to Fabric using Azure DevOps?

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🛠️ Our Goal

To build a secure, automated Azure DevOps pipeline that:

• Deploys artifacts to a Fabric workspace
• Works reliably across environments (Dev, Test, Prod)

[burakkaragoz · Accepted solution]

Hi @Shiva3 ,

Great question—this is a common stumbling block when automating Fabric deployments with Azure DevOps and service principals. Here’s a detailed breakdown and best practices:

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1. Why does DefaultAzureCredential fail during deployment even after successful authentication?

• Different Contexts in Pipeline:
  Authentication might succeed during the initial stages (e.g., in Azure DevOps tasks), but when the deployment script (deploy.py) runs, it could be executed in a different context or environment variable scope. The DefaultAzureCredential flow checks multiple credential sources and may not pick up your service principal as expected during the script run.

• Missing Environment Variables:
  Ensure that all required environment variables (AZURE_CLIENT_ID, AZURE_TENANT_ID, AZURE_CLIENT_SECRET) are available in the context where deploy.py executes—not just in the pipeline, but for any subprocesses as well.

• Token Caching/Expiration:
  If there’s a delay or context switch, the acquired token may expire or not be forwarded properly between steps.

• User vs. Service Principal Permissions:
  Sometimes, the initial authentication uses a user identity, but the deploy script is forced to use a service principal, which may lack certain permissions on the Fabric workspace or resources.

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2. Fabric-Specific Configurations or SDK Requirements

• Required Permissions:
  Double-check that your service principal has all the necessary permissions on the Fabric workspace (Contributor or higher, Data Admin roles if needed).

• Supported SDK/CLI:
  Make sure you’re using the latest Azure SDKs compatible with Microsoft Fabric, and that your service principal is granted necessary RBAC roles both in Azure and in Fabric itself.

• Service Connection in Azure DevOps:
  If using an Azure Resource Manager service connection, verify that it’s set to use the correct service principal and that it’s available to all pipeline tasks and scripts.

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3. Working Example / Best Practice

Best Practice:
Set the required environment variables explicitly in the pipeline before running your Python deployment script, so DefaultAzureCredential always picks up the correct credentials.

Example YAML snippet:

YAML

- task: Bash@3
  env:
    AZURE_CLIENT_ID: $(servicePrincipalId)
    AZURE_TENANT_ID: $(tenantId)
    AZURE_CLIENT_SECRET: $(servicePrincipalKey)
  inputs:
    targetType: 'inline'
    script: |
      python deploy.py

Python (deploy.py) snippet:

Python

from azure.identity import DefaultAzureCredential
from azure.mgmt.resource import ResourceManagementClient

credential = DefaultAzureCredential()
client = ResourceManagementClient(credential, "<subscription_id>")
# ... your deployment logic ...

• Make sure the pipeline variables (servicePrincipalId, tenantId, servicePrincipalKey) are populated from your Azure DevOps service connection.

Extra Tips:

• If you’re using managed identities (e.g., Microsoft-hosted agent with Managed Identity enabled), ensure the identity has permissions in both Azure and Fabric.
• Use az login with service principal before script runs to confirm credentials are valid (for debugging).
• Log the current principal in your script to be sure which identity is being used.

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Let me know if you need a full working pipeline example or if you hit any other errors—happy to help you troubleshoot further!