When running cerebro's docker image the following environment variable must be set.
AUTH_TYPE: must be set tobasicBASIC_AUTH_USERBASIC_AUTH_PWD
This docker-compose shows how to configure cerebro with basic auth and the user admin/admin.
In order to configure basic auth with admin/admin user just run the following command:
./bin/cerebro -DAUTH_TYPE=basic -DBASIC_AUTH_USER=admin -DBASIC_AUTH_PWD=admin
If overriding more settings is needed, it might be more convenient to create your application.conf file as explainded here