For AdminUI to work out of the box, it has some behaviour turned on by default that inserts the required data into the IdentityServer, Identity, and AdminUI database tables on the app start if missing. If the user table is empty, this also inserts a default user into the database on the first start-up.
You can disable this functionality in the app's configuration. Help for configuring AdminUI can be found here.
The bootstrapping in AdminUI is not concurrency safe, so if you were to have multiple instances of AdminUI running, you would need to disable bootstrapping to avoid running into errors when trying to start AdminUI for the first time.
If you disable Bootstrapping, we have added the ability to run it manually using the AdminUI binaries via the command line, which can also be done for migrations.
You can do this by navigating to your AdminUI install directory and locating the IdentityExpress.Manager.UI.dll; you can run the dll using
dotnet IdentityExpress.Manager.UI.dll -bootstrap