How to configure client secret for admin-cli in master realm on keycloak docker

Im trying to setup keycloak docker. By default keycloak creates master realm with few clients. The admin-cli has all rights in all the realms, So is it possible to configure to stop public access and have client secret on startup.

As per the documentation I can configure admin user/password through KEYCLOAK_USER and KEYCLOAK_PASSWORD environment variables. But I don’t see any configuration to provide client secret to admin-cli client on keycloak startup