ANCM (In-proc) can cause IIS worker process to become unhealthy

[HaoK]

We've seen various reports of IIS worker processes becoming unresponsive/returning 503s until things are iisreset. Out-of-Process hosting seems to fix many of these issues.

From older bugs like (#14719) it seems like background exceptions are maybe expected to cause the worker process to crash?

This issue will track investigating and resolving the root cause:

Potentially related issues:

• Blazor running under IIS starts throwing 503 without any error.  #42661
• Blazor hosted site thorw 503 on IIS and IIS Express, works fine in kestrel #40494
• IIS In Process aspnetcore process failing to start under load #41770
• SPA running under IIS go to 503 but w3wp dont stop #44108
• IIS does not recover from a broken web.config in v6 hosting bundle where it used to in v3 and v5 #40194
• IIS InProcess-hosting not restarting the process after unhandled exception occurred #22507
• IIS Express 503 after working fine for days with blazor app #17781
• 3.0. When the application pool is recycled, it crashes directly #14719

[ghost]

Thanks for contacting us.

We're moving this issue to the .NET 8 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.

[HaoK]

Looks like at least for some of the SQL related issues we were seeing, it was indeed a bug in Sql Client: dotnet/SqlClient#1418