Crear un usuario raíz específico y un nombre de host que no funcione

Uso de la image del docker de wordpress / mariadb Deseo instalar WordPress localmente con la siguiente configuration pnetworkingeterminada,

DB_NAME: mysite_wp DB_USER: myuser DB_PASSWORD: mypw DB_HOST: localhost 

Usando el file docker-componse.yml

 version: '2' services: wordpress: image: wordpress ports: - 8080:80 environment: WORDPRESS_DB_NAME: mysite_wp WORDPRESS_DB_USER: myuser WORDPRESS_DB_PASSWORD: mypw volumes: - ./src:/var/www/html mysql: image: mariadb environment: MYSQL_ROOT_PASSWORD: mypw MYSQL_USER: myuser MYSQL_PASSWORD: mypw volumes: - ./db/mysite_wp.sql:/docker-entrypoint-initdb.d/mysite_wp.sql 

Estoy recibiendo un error

 wordpress_1 | MySQL Connection Error: (1045) Access denied for user 'myuser'@'172.18.0.3' (using password: YES)