There is the possibility to define admin user/password with environment variables for Keycloak 20.0.3.

During the very first initial startup, Keycloak will create this admin user successfully.

During the future startup's of Keycloak, I get the following error message:

ERROR [org.keycloak.services] (main) KC-SERVICES0010: Failed to add user 'admin' to realm 'master': user with username exists

I get this error message, because this admin user were already created during the very first initial startup.

Is it really necessary to define this behaviour as a "ERROR", is it not enough to define it as a "WARN"?

Thank you for your feedback!