Azure Function App: Test/Run with payload works on Flex Consumption but fails on Elastic Premium

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Azure Function App: Test/Run with payload works on Flex Consumption but fails on Elastic Premium

Varsha Vishwakarma (AVANADE INC) 40 Microsoft External Staff

I have an Azure Function App deployed using Run From Package.

Hosting Plan: Elastic Premium
Deployment Method: ZIP package
App Setting: WEBSITE_RUN_FROM_PACKAGE = 1

On Flex Consumption, I can use the Test/Run feature in the Azure Portal to send a payload and validate the API without modifying files. However, on Elastic Premium, the same Test/Run action fails (or does not behave as expected).

I am getting notification in elastic premium functionapp "Your app is currently in read only mode because you are running from a package file. To make any changes update the content in your zip file and WEBSITE_RUN_FROM_PACKAGE app setting."

Pravallika KV 2,690 Reputation points Microsoft External Staff Moderator

2025-12-04T19:17:22.6766667+00:00
Hi Varsha Vishwakarma (AVANADE INC) ,

Thanks for reaching out to Microsoft Q&A.

When your Function App is running from a package(by setting WEBSITE_RUN_FROM_PACKAGE = 1), it is indeed restricted in terms of making changes directly through the portal, which is a behavior tied to how Elastic Premium handles packaged deployments

Could you please share below details:

Have you checked the Kudu logs for any errors when you attempt to use the Test/Run feature?

What specific error message are you receiving when the Test/Run action fails?
Varsha Vishwakarma (AVANADE INC) 40 Reputation points Microsoft External Staff

2025-12-04T19:47:29.7166667+00:00

Pravallika KV

I can’t check the Kudu logs because I’m unable to test the deployed function by passing a payload in the request body of test/run. I believe this is due to the read-only file system caused by the WEBSITE_RUN_FROM_PACKAGE setting.
Pravallika KV 2,690 Reputation points Microsoft External Staff Moderator

2025-12-04T20:01:36.8866667+00:00

To resolve the error encountered an error (InternalServerError) from host runtime when running your Azure Function, please make sure that all the required application settings in your function app are properly defined and verified the usage section, as missing or incorrect settings can lead to a 500 error.

Review the function's configuration and code to ensure everything is structured and set up correctly. If the issue continues, try redeploying the function, as this can sometimes fix deployment related issues. Make sure you're using the latest version of the Azure Functions extension in Visual Studio Code to avoid compatibility problems.

There could be multiple reasons for 500 errors, so I would recommend validating the Diagnose and solve problems on your function app to get detailed insights into any issues and to view suggested actions for resolution.

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Pravallika KV 2,690 Reputation points Microsoft External Staff Moderator

2025-12-04T19:17:22.6766667+00:00

Hi Varsha Vishwakarma (AVANADE INC) ,

Thanks for reaching out to Microsoft Q&A.

When your Function App is running from a package(by setting WEBSITE_RUN_FROM_PACKAGE = 1), it is indeed restricted in terms of making changes directly through the portal, which is a behavior tied to how Elastic Premium handles packaged deployments

Could you please share below details:

Have you checked the Kudu logs for any errors when you attempt to use the Test/Run feature?

What specific error message are you receiving when the Test/Run action fails?
Varsha Vishwakarma (AVANADE INC) 40 Reputation points Microsoft External Staff

2025-12-04T19:47:29.7166667+00:00

Pravallika KV

I can’t check the Kudu logs because I’m unable to test the deployed function by passing a payload in the request body of test/run. I believe this is due to the read-only file system caused by the WEBSITE_RUN_FROM_PACKAGE setting.
Pravallika KV 2,690 Reputation points Microsoft External Staff Moderator

2025-12-04T20:01:36.8866667+00:00

To resolve the error encountered an error (InternalServerError) from host runtime when running your Azure Function, please make sure that all the required application settings in your function app are properly defined and verified the usage section, as missing or incorrect settings can lead to a 500 error.

Review the function's configuration and code to ensure everything is structured and set up correctly. If the issue continues, try redeploying the function, as this can sometimes fix deployment related issues. Make sure you're using the latest version of the Azure Functions extension in Visual Studio Code to avoid compatibility problems.

There could be multiple reasons for 500 errors, so I would recommend validating the Diagnose and solve problems on your function app to get detailed insights into any issues and to view suggested actions for resolution.

Answer 1

Hi Varsha Vishwakarma (AVANADE INC),

Thanks for our offline conversation, Glad your issue is resolved.

Upon investigating further, it was identified that the issue was due to missing roles required for the Function App to run using its Managed Identity.

Solution:

Go to the Storage Account => IAM => Add Role Assignment
Assign the following roles to the Function App's Managed Identity:

Storage Blob Data Contributor
Storage Queue Data Contributor

Hope it helps!

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Azure Function App: Test/Run with payload works on Flex Consumption but fails on Elastic Premium

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