When multiple Blazor apps are published to IIS we get HTTP Error 500.35 - ASP.NET Core does not support multiple apps in the same app pool

Question

We currently have an IIS server with 50 ASP.NET applications that are all in the same app pool. Our plan is to upgrade them all to Blazor with .NET 5. When we publish two different Blazor applications on our server, the first application that we open works but we get this error after opening the second one: ASP.NET Core does not support multiple apps in the same app pool

This error makes sense but to solve it, I've only been able to find this on Google: https://codepattern.net/Blog/post/dot-net-core-specific-production-issues Which just says to create new app pools. It doesn't appear that we can do that for every single one of our 50 applications, it would take up too many resources. Is there anything else we can do?

Some more googling finds this: HTTP Error 500.35 - ANCM Multiple In-Process Applications in same Process ASP.NET Core 3 But this has different wording and I tried the solution they gave and it didn't work.

I also tried looking through the solution's applicationhost.config but I don't really know where to start with that.

score 2 · Answer 1 · answered Jun 08 '21 at 08:15

2

The worker process can't run both an in-process app and an out-of-process app in the same process. To fix this error, I recommend to run apps in separate IIS application pools.

Change to use OutOfProcess mode.
Order several hosting plan to run inprocess and outprocess app separately.

answered Jun 08 '21 at 08:15

samwu

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I've been told by the people over me that more application pools use more resources. I suppose it's not as bad as it sounded? – CuriousCarnivore Jun 08 '21 at 13:34
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Yes, but i think it is necessary. – samwu Jun 09 '21 at 09:13

When multiple Blazor apps are published to IIS we get HTTP Error 500.35 - ASP.NET Core does not support multiple apps in the same app pool

1 Answers1