Keep ASP.NET core app running all the time in IIS

Question

I am hosting an ASP.NET Core (2.2) app in IIS.

The app is using a custom app pool with below settings:

.NET CLR version: No Managed Code
Start Mode: Always Running
Idle Time-out (minutes): 0

My startup code looks like:

WebHost.CreateDefaultBuilder(args)
  .UseStartup<MyStartup>() 
  .Build() 
  .Run();

I am expecting that the app will always run, but after some time the app stops after getting below request:

[Microsoft.AspNetCore.Hosting.Internal.WebHost] Request starting HTTP/1.1 POST http://127.0.0.1:43745/app/iisintegration 0 [Microsoft.AspNetCore.Hosting.Internal.WebHost] Request finished in 5.7107ms 202

The app is a sub app. The parent app is using different app pool, and does have idle time-out.

Is there some setting I am missing to keep the app up all the time ?

Answer 1

Found a solution which is working. You need to host your ASP.NET Core 2.2 app using in-process hosting model. Below steps can be followed for it.

1. Install Application Initialization Module (IIS)

Server Manager > Add roles and Features > Server Roles > Web Server (IIS) > Application Development > Application Initialization

2. IIS > Your App Pool > Start Mode > Always Running

3. IIS > Your App Pool > Idle Time-out > 0

4. IIS > Your App > Advanced Settings > Preload Enabled > True

5. Setup your app for In-Process hosting model (web.config changes for Asp.net core module and code changes to set correct current directory)

More information can be found at:

• https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/iis/?view=aspnetcore-2.2

• https://github.com/aspnet/AspNetCore.Docs/issues/12232

• https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/aspnet-core-module?view=aspnetcore-2.2

• https://github.com/aspnet/AspNetCore/issues/6075