ASP.Net Core Identity login status lost after deploy

Question

I am using ASP.Net Core and MS Identity, I try to understand why after each deployment the login users are logged out. I am running on a IIS 8.5

I have been trying t

Answer 1

(solution split into a separate answer following Chris comment)

I found a solution to keep the login status, it survives website stop/start, and an update of the website source folder:

public void ConfigureServices(IServiceCollection services)
{
    services.AddDataProtection()
            // This helps surviving a restart: a same app will find back its keys. Just ensure to create the folder.
            .PersistKeysToFileSystem(new DirectoryInfo("\\MyFolder\\keys\\"))
            // This helps surviving a site update: each app has its own store, building the site creates a new app
            .SetApplicationName("MyWebsite")
            .SetDefaultKeyLifetime(TimeSpan.FromDays(90));
}

With these additional lines and the machine key set, the login data stays after site stop/start and IIS server restart, and if the site is rebuilt.

More information there: https://docs.microsoft.com/en-us/aspnet/core/security/data-protection/configuration/overview

More proposed by justserega: https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/iis/?tabs=aspnetcore2x#data-protection