Migrate Azure function from in-process model to isolated model

Question

I have an Azure function app running on the in-process model. Now I'm migrating it to the isolated model. I did the code change required and changed the FUNCTIONS_WORKER_RUNTIME to dotnet-isolated and .NET Version change to .NET Isolated.

Project cs file has Sdk="Microsoft.NET.Sdk.Worker" and property group is as below

<Project Sdk="Microsoft.NET.Sdk.Worker">

<PropertyGroup>

<TargetFramework>net8.0</TargetFramework>

  <AzureFunctionsVersion>v4</AzureFunctionsVersion>

  <OutputType>Exe</OutputType>

  <Nullable>enable</Nullable>

  <ImplicitUsings>enable</ImplicitUsings>

  <EnableDefaultContentItems>false</EnableDefaultContentItems>

<FunctionsWorkerRuntime>dotnet-isolated</FunctionsWorkerRuntime>

</PropertyGroup>

And when deployed on azure it shows a warning.
"The 'FUNCTIONS_WORKER_RUNTIME' is set to 'dotnet-isolated', which does not match the worker runtime metadata found in the deployed function app artifacts. The deployed artifacts are for 'dotnet'."

Kindly share suggestions.

Answer 1

The warning you're seeing means that Azure is detecting in-process (dotnet) function artifacts, even though your environment variable FUNCTIONS_WORKER_RUNTIME is set to dotnet-isolated. To fix this, try the following:

1. Ensure your project is fully converted to isolated
   • Project SDK should be:

          <Project Sdk="Microsoft.NET.Sdk.Worker">
     

   • Confirm that the entry point uses Host.CreateDefaultBuilder() and UseFunctionsWorker() instead of FunctionStartup or in-process patterns.
   • You should not be referencing Microsoft.NET.Sdk.Functions — only Microsoft.Azure.Functions.Worker.
2. Remove any bin / obj folders
   • Leftover build artifacts from the in-process model can confuse the deployment:

          dotnet clean
          rm -rf bin obj
     

3. Verify the function bindings are compatible
   • Ensure that you're using the Microsoft.Azure.Functions.Worker.* packages for bindings (e.g. Http, Timer, etc.), not the Microsoft.Azure.WebJobs.* or Microsoft.Azure.Functions.Extensions.
4. Check dependencies
   • In .csproj, dependencies should look something like this:

          <ItemGroup>
            <PackageReference Include="Microsoft.Azure.Functions.Worker" Version="1.16.0" />
            <PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="1.16.0" OutputItemType="Analyzer" />
            <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http" Version="3.1.0" />
          </ItemGroup>
     

5. Set EnableDefaultContentItems to true or remove it
   • You currently have:

          <EnableDefaultContentItems>false</EnableDefaultContentItems>
     

     This might prevent required function metadata files from being included in the build output. Try either removing this or setting it to true.
6. Check deployment artifacts
   • Make sure the function.json files being generated are from isolated worker functions. They should be auto-generated at build time by the worker SDK, and not manually included.
7. Perform a fresh publish
   • Clean and rebuild:

          dotnet build
     

   • Publish locally to verify outputs:

          dotnet publish -c Release -o ./publish
     

   • Deploy only from that publish folder. If you're using Azure DevOps, GitHub Actions, or any CI/CD, ensure it is not reusing previous build artifacts or pointing to a dotnet-style function app.

If this doesn't help, try redeploying into a fresh Function App (or delete the existing one and recreate it). Sometimes stale runtime metadata can cause Azure to interpret your deployment incorrectly.

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hth

Marcin