Installing Hosting-Bundle with /norestart restarts IIS

Hi,

I'm running an old web application, one main service, 4 additional services (productive and test, so 10 applications), all IIS In-Process hostet / Minimal Api (Windows Server 2019). Additional, a collection of functions on the DbServer, same configuration (IIS-In-Process, minimal api).

Regular patch day: Installation of the newest SDK, two years NET.8, now NET.10. I'm using something like a green/blue / proxy solution, every service exists in 2 versions. Traffic goes to main system 1, system 2 stopped, restarted, runs with the new version, traffic switch to system 2, system 1 stopped, restarted, runs with new, switch back. So no interruption, if I update the SDK.

Update of the Hosting-Bundle: Sometimes, rare, not monthly.

Updated the hosting bundle last year without any switch: Oh, IIS and all services were restarted. Didn't expect that, didn't want that.

Updated the hosting bundle some months later, used the /norestart - switch: No IIS restart, good. That's not really a problem, I combine this with a regular patch, then follows a reboot, so the AspNetCoreModuleV2 is updated.

Now, NET.10.0.1: Installed the newest hosting bundle, again with /norestart. Result: All IIS services are restarted. Both servers.

Is this a bug? Or is there a hidden option to supress the IIS reload? I know that a IIS restart is required to replace the old AspNetCoreModuleV2 version with the newer one. But it's ok if this restart comes with the next reboot.

Can't and don't want to reproduce this / test it again. It's a productive system.

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Summary: It should be possible to install the newest hosting bundle without an immediate IIS-restart. A restart is required, but a following reboot will fix it.