The following app setting Site.SiteConfig.AppSettings.FUNCTION_WORKER_RUNTIME for flex consumptition sites is invalid

Question

The following app setting Site.SiteConfig.AppSettings.FUNCTION_WORKER_RUNTIME for flex consumptition sites is invalid

Mirra Artificial Intelligence 0

Hello,

I am trying to upload code to my function app on flex cunsomption plan. Doing it using core tools didn't work, so I am trying using Azure Cli.

The following command returns a success code:

az functionapp deployment source config-zip -g {my_resource_group} -n {my_application} --src {my_zip_file}.zip

But no functions are displayed in the "functions" tab (they are successfully displaed and called when running locally).

I suspect the reason is that the "FUNCTIONS_WORKER_RUNTIME" is not set among the environment variables. My functions runs in the "dotnet-isolated" runtime. So I try to set this variable to "dotnet-isolated" and get the following error:

"The following app setting (Site.SiteConfig.AppSettings.FUNCTIONS_WORKER_RUNTIME) for Flex Consumption sites is invalid. Please remove or rename it before retrying."

Any help would be appreciated.

Sai Prabhu Naveen Parimi 2,510 Reputation points Microsoft External Staff Moderator

2025-04-08T05:09:00.4166667+00:00
@Mirra Artificial Intelligence

Thanks for sharing the issue you're encountering with the FUNCTIONS_WORKER_RUNTIME setting on your Azure Function App using the Flex Consumption plan.

To help address it, I’d recommend the following:

Remove the FUNCTIONS_WORKER_RUNTIME app setting, as it's not supported in the Flex Consumption plan:

az functionapp config appsettings delete \ --name <your-app-name> \ --resource-group <your-resource-group> \ --setting-names FUNCTIONS_WORKER_RUNTIME

Make sure the app was created using the correct runtime stack (such as dotnet-isolated, if that's what you're using). This is specified during creation and can't be changed afterward. If needed, re-creating the app with the right runtime settings might be the simpler option.

References:

Flex Consumption plan deprecations

Azure Functions Flex Consumption plan hosting

Let me know if this helps resolve the issue or if you're still running into problems
Mirra Artificial Intelligence 0 Reputation points

2025-04-08T13:53:39.7833333+00:00

Hello! Thanks for your response.

If I delete this setting, no function appears after my deploy, as I mentioned.

I can guarantee the functions exist, as they appear normally when I deploy this same function to a windows function app.
Sai Prabhu Naveen Parimi 2,510 Reputation points Microsoft External Staff Moderator

2025-04-10T09:32:30.1733333+00:00
@Mirra Artificial Intelligence

Thanks for your update. Since you're deploying to a Function App on the Flex Consumption plan and not seeing any functions after deployment, here are two quick things to check:

1. Confirm the app was created with the correct runtime (dotnet-isolated) Run this command:

az functionapp show --name <your-app-name> --resource-group <your-resource-group> --query siteConfig.linuxFxVersion

If it doesn't return something like "DOTNET-ISOLATED|8.0", the app was created with the wrong runtime and will need to be re-created.

2. Ensure the zip structure is correct Unzip your deployment file and check that the .dll and function.json files are at the root or directly inside function folders — not nested too deep.

Structure should look like:

FunctionApp.dll /MyFunction/function.json

If the zip contains folders like /release/net8.0/publish, it won’t work.

Let me know what you find — happy to help further!
Sopori, Ayush 0 Reputation points

2025-04-11T09:51:37.49+00:00

I am facing similar kind of issue as mentioned above. I have build a function app using python script and now I am trying to deploy the function app under Flex Consumption plan in azure. The deployment is successful but I am unable to see my function app and also there are no logs recorded under deployment center.
Mirra Artificial Intelligence 0 Reputation points

2025-04-11T14:50:43.3766667+00:00

Hello,

The function has the correct runtime, as stated by the image.

Following your feedback, I have tried to zip the release/bin file instead of the root file, but still didn't work.

Do you have any documentation on the proper way of mounting this zip?

Thanks!
Sai Prabhu Naveen Parimi 2,510 Reputation points Microsoft External Staff Moderator

2025-04-14T09:31:09.4833333+00:00

@Mirra Artificial Intelligence

Thanks for following up!

If you're looking for some official docs that cover ZIP deployments and .NET isolated functions, these two should be helpful:

Deploy code with ZIP push – this one explains how ZIP deploy works using the Azure CLI.

.NET Isolated Process Functions Guide – good reference for building and publishing .NET isolated apps the right way.

Hope these helps point you in the right direction.
Mirra Artificial Intelligence 0 Reputation points

2025-04-14T15:23:47.2266667+00:00

Hello,

The documentation states zip deployment does not work with flex consumption instances.

As an alternative, I tried to deploy using Core tools:

func azure functionapp publish {my_application}

It just creates an "wamrUp" default function, but can't find any of the functions actually inside the code:

Deploying through Visual Studio also don't show me my functions.

What am I missing here?

Thanks!
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-16T12:17:47.9866667+00:00
Have you added below setting under Function App=>Environment Variables=>App Settings?

SCM_DO_BUILD_DURING_DEPLOYMENT=true
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-17T05:49:23.2533333+00:00

Mirra Artificial Intelligence, Just checking in to see if the issue is resolved. If you have any further queries, do let us know.
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-18T04:30:15.85+00:00

Mirra Artificial Intelligence, Just checking in to see if the provided answer helped. Kindly consider upvoting the comment if the information provided is helpful. This can assist other community members in resolving similar issues. If any other further queries - feel free to reach out!
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-21T03:36:51.58+00:00

Mirra Artificial Intelligence, We still have not heard back from you. Could you please let us know if the information provided was helpful? If it resolves your query, Kindly consider upvoting the comment. This can assist other community members in resolving similar issue. Additionally, if you have any further questions, please let us know.

1 answer

Your answer

Sai Prabhu Naveen Parimi 2,510 Reputation points Microsoft External Staff Moderator

2025-04-08T05:09:00.4166667+00:00

@Mirra Artificial Intelligence

Thanks for sharing the issue you're encountering with the FUNCTIONS_WORKER_RUNTIME setting on your Azure Function App using the Flex Consumption plan.

To help address it, I’d recommend the following:

Remove the FUNCTIONS_WORKER_RUNTIME app setting, as it's not supported in the Flex Consumption plan:

az functionapp config appsettings delete \ --name <your-app-name> \ --resource-group <your-resource-group> \ --setting-names FUNCTIONS_WORKER_RUNTIME

Make sure the app was created using the correct runtime stack (such as dotnet-isolated, if that's what you're using). This is specified during creation and can't be changed afterward. If needed, re-creating the app with the right runtime settings might be the simpler option.

References:

Flex Consumption plan deprecations

Azure Functions Flex Consumption plan hosting

Let me know if this helps resolve the issue or if you're still running into problems
Mirra Artificial Intelligence 0 Reputation points

2025-04-08T13:53:39.7833333+00:00

Hello! Thanks for your response.

If I delete this setting, no function appears after my deploy, as I mentioned.

I can guarantee the functions exist, as they appear normally when I deploy this same function to a windows function app.
Sai Prabhu Naveen Parimi 2,510 Reputation points Microsoft External Staff Moderator

2025-04-10T09:32:30.1733333+00:00

@Mirra Artificial Intelligence

Thanks for your update. Since you're deploying to a Function App on the Flex Consumption plan and not seeing any functions after deployment, here are two quick things to check:

1. Confirm the app was created with the correct runtime (dotnet-isolated) Run this command:

az functionapp show --name <your-app-name> --resource-group <your-resource-group> --query siteConfig.linuxFxVersion

If it doesn't return something like "DOTNET-ISOLATED|8.0", the app was created with the wrong runtime and will need to be re-created.

2. Ensure the zip structure is correct Unzip your deployment file and check that the .dll and function.json files are at the root or directly inside function folders — not nested too deep.

Structure should look like:

FunctionApp.dll /MyFunction/function.json

If the zip contains folders like /release/net8.0/publish, it won’t work.

Let me know what you find — happy to help further!
Sopori, Ayush 0 Reputation points

2025-04-11T09:51:37.49+00:00

I am facing similar kind of issue as mentioned above. I have build a function app using python script and now I am trying to deploy the function app under Flex Consumption plan in azure. The deployment is successful but I am unable to see my function app and also there are no logs recorded under deployment center.
Mirra Artificial Intelligence 0 Reputation points

2025-04-11T14:50:43.3766667+00:00

Hello,

The function has the correct runtime, as stated by the image.

Following your feedback, I have tried to zip the release/bin file instead of the root file, but still didn't work.

Do you have any documentation on the proper way of mounting this zip?

Thanks!
Sai Prabhu Naveen Parimi 2,510 Reputation points Microsoft External Staff Moderator

2025-04-14T09:31:09.4833333+00:00

@Mirra Artificial Intelligence

Thanks for following up!

If you're looking for some official docs that cover ZIP deployments and .NET isolated functions, these two should be helpful:

Deploy code with ZIP push – this one explains how ZIP deploy works using the Azure CLI.

.NET Isolated Process Functions Guide – good reference for building and publishing .NET isolated apps the right way.

Hope these helps point you in the right direction.
Mirra Artificial Intelligence 0 Reputation points

2025-04-14T15:23:47.2266667+00:00

Hello,

The documentation states zip deployment does not work with flex consumption instances.

As an alternative, I tried to deploy using Core tools:

func azure functionapp publish {my_application}

It just creates an "wamrUp" default function, but can't find any of the functions actually inside the code:

Deploying through Visual Studio also don't show me my functions.

What am I missing here?

Thanks!
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-16T12:17:47.9866667+00:00

Have you added below setting under Function App=>Environment Variables=>App Settings?

SCM_DO_BUILD_DURING_DEPLOYMENT=true
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-17T05:49:23.2533333+00:00

Mirra Artificial Intelligence, Just checking in to see if the issue is resolved. If you have any further queries, do let us know.
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-18T04:30:15.85+00:00

Mirra Artificial Intelligence, Just checking in to see if the provided answer helped. Kindly consider upvoting the comment if the information provided is helpful. This can assist other community members in resolving similar issues. If any other further queries - feel free to reach out!
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-21T03:36:51.58+00:00

Mirra Artificial Intelligence, We still have not heard back from you. Could you please let us know if the information provided was helpful? If it resolves your query, Kindly consider upvoting the comment. This can assist other community members in resolving similar issue. Additionally, if you have any further questions, please let us know.

Answer 1

Pravallika Kothaveeranna Gari 955 Microsoft External Staff Moderator

Hi Mirra Artificial Intelligence,

Make sure you have below settings added in Azure function App with Flex Consumption under Settings=>Environment Variables=>App Settings.


"DEPLOYMENT_STORAGE_CONNECTION_STRING"

"AzureWebJobsStorage"

"APPLICATIONINSIGHTS_CONNECTION_STRING(If needed)

enter image description here

Validate the Storage configuration of function App under Deployment Settings.

enter image description here

You can zip deploy the function to flex consumption plan using Azure CLI.

I have tested the same and able to perform zip deploy using command az functionapp deployment source config-zip -g "Resourcegroup" -n FunctionappName --src "FunctionProject.zip" --build-remote true.


D:\a\_work\1\s\build_scripts\windows\artifacts\cli\Lib\site-packages\cryptography/hazmat/backends/openssl/backend.py:17: UserWarning: You are using cryptography on a 32-bit Python on a 64-bit Windows Operating System. Cryptography will be significantly faster if you switch to using a 64-bit Python.

Getting scm site credentials for zip deployment
Starting zip deployment. This operation can take a while to complete ...
Deployment endpoint responded with status code 202 for deployment id "6643302e-9612-4d6b-b6e4-72881fb048af"
Waiting for sync triggers...
Checking the health of the function app
"Deployment was successful.

Portal:

Deployed function is available under FunctionApp=>Overview.

enter image description here Hope it helps!

Please do not forget to click "Accept the answer” and Yes wherever the information provided helps you, this can be beneficial to other community members.

User's image

If you have any other questions or still running into more issues, let me know in the "comments" and I would be happy to help you.

Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-21T10:03:37.1866667+00:00

Mirra Artificial Intelligence, Just checking in to see if the provided answer helped. If it did, please click "Accept the answer” and Yes for the answer . So it can benefit other community members reading this thread. If you have any further queries, do let us know.
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-22T03:44:09.1833333+00:00

Mirra Artificial Intelligence, We still have not heard back from you. Please click "Accept the answer” and Yes for the answer. So, it can benefit other community members reading this thread. If you have any further queries, do let us know.
Mirra Artificial Intelligence 0 Reputation points

2025-04-22T20:04:48.24+00:00
Hello Pravallika,

Thanks for your time!

All of these variables are configured correctly, as I checked.

When I try to run the command with the --build-remote true sufix, I get the following error:

Failed during oryx build due to \\n/opt/Kudu/Scripts/starter.sh oryx build /tmp/zipdeploy/extracted -o /home/site/wwwroot --platform dotnet

My current zip structure looks like this:

*{src_folders}* *bin* *obj* *{my_project}.csproj* *program.cs host.json* *local.settings.json*

Is everything correct?

Thank you again!
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-25T03:36:39.71+00:00

Hi Mirra Artificial Intelligence,

Apologies for the delay in response. Could you please share your local.settings.json?

Mirra Artificial Intelligence 0

Hello Pravallika,

No problems! Here is my local.settings:

{
  "IsEncrypted": false,
  "Values": {
    "AzureWebJobsStorage": "UseDevelopmentStorage=true",
    "FUNCTIONS_WORKER_RUNTIME": "dotnet-isolated"

  },

  "TokenConfigurations": {
    "Audience": "MyAudience",
    "FinalExpiration": 129600,
    "Issuer": "MyIssuer",
    "Seconds": 86400
  },
  "Host": {
    "CORS": "*", 
    "CORS_AllowedOrigins": "*" 
  }
}

Thanks!

Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-28T10:53:15.0133333+00:00
Mirra Artificial Intelligence, Make sure FunctionProject.zip file contains the contents of the project, not a parent folder.

Open the project folder, select all the files and zip it.

For example:

Correct structure inside ZIP:

- host.json - bin/ - FunctionName/

Incorrect structure:

- FunctionProject/ - host.json
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-04-30T04:58:24.0833333+00:00

Mirra Artificial Intelligence, Just checking in to see if the provided information helped. If you have any further queries, do let us know.
Mirra Artificial Intelligence 0 Reputation points

2025-04-30T17:53:44.0133333+00:00
Hello Pravallika,

Correct, the zip folder contains the content of the project! It's exact composition is the following:

bin/

{src_folders}/

Obj

Properties

host.json

local.settings.json

Program.cs

{my_project}.csproj

{my_project}.csproj.user

After retrying the deploy, it shows a successful message:

"Getting scm site credentials for zip deployment Starting zip deployment. This operation can take a while to complete ... Deployment endpoint responded with status code 202 for deployment id "a2712c20-70d7..." Waiting for sync triggers... Checking the health of the function app"

However, it continues to only show a default "Http WarmUp" function on azure:

When running locally, I can see all my functions:

Thanks again!
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-05-05T03:47:35.3366667+00:00

Can you create a new function app with different plan and check if you are facing the same issue with deployment?
Mirra Artificial Intelligence 0 Reputation points

2025-05-06T19:12:43.1266667+00:00

Hello Pravallika,

I can deploy it succesfully on a consumption plan (in a windows machine) using Visual Studio Deployment or Azure DevOps pipelines deployment.

I cannot deploy it anywhere using zip deployment. I also cannot deploy it to this Linux machine on my Flex Consumption plan using Visual Studio Deployment (basically due to the same error of not listing my functions) or Azure Pipelines DevOps deployment (there seems to be no azure function pipeline for Linux machines).

Thanks!
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-05-08T06:42:56.4833333+00:00

Hi Mirra Artificial Intelligence, lets continue the discussion in private chat. Here is the reference link on How to access & Data Privacy policy of private messages in Microsoft QnA.
Mirra Artificial Intelligence 0 Reputation points

2025-05-12T13:51:10.15+00:00

Ok! How can we do it? The "How to access" link is giving me a Bad Request.
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-05-13T14:11:44.95+00:00

Click on the Private messages option below the question.
Pravallika Kothaveeranna Gari 955 Reputation points Microsoft External Staff Moderator

2025-05-15T06:41:34.9633333+00:00

Hi Mirra Artificial Intelligence, Please check the private messages.

Share via

The following app setting Site.SiteConfig.AppSettings.FUNCTION_WORKER_RUNTIME for flex consumptition sites is invalid

1 answer

Your answer