How To Configure Your .Net Core Web App to Run OutOfProcess and Publish It That Way

I put a .Net Core web site on my new webhost, SmarterASP.Net and published it from within Visual Studio 2019 with no problems. A few weeks later I added a second .Net Core web site to my account and published it the same way then discovered my sites were returning 500.34 and/or 500.35 errors.

Both of my sites are running in the same App Pool on IIS and are using the defaults for .Net Core 3.1 which means they are runnning “inprocess”. But we can only have one .Net Core 3.1 app running “inprocess”. I needed to move both of them to run “outofprocess”, which means they will run on Kestrel instead of IIS. I have no concerns about that, but I had trouble figuring out how to tell my “publish” profile in Visual Studio that I wanted the deployed site to run OutOfProcess. There is an option in the Project Properties Debug tab, but that does not carry over to the web.config that gets created when I publish my app through Visual Studio using FTP.

To change a .Net Core 3.1 app to OutOfProcess so that when you publish it the web.config for the published site also uses OutOfProcess, you need to manually edit your .csproj file and add an attribute AspNetCoreHostingModel in the Property Group that has your TargetFramework:

  <PropertyGroup>

    <TargetFramework>netcoreapp3.1</TargetFramework>

    <AspNetCoreHostingModel>OutOfProcess</AspNetCoreHostingModel>

  </PropertyGroup>

A few helpful links with more info if needed: https://www.smarterasp.net/support/kb/a1999/what-should-we-do-when-get-http-error-500_34-ancm-mixed-hosting-models-not-supported.aspx?KBSearchID=717082

http://binaryintellect.net/articles/bb086279-ed2a-4628-85f2-7e91125fbe57.aspx