RUN apk add mariadb mariadb-client \  /* 1. install mariadb                   */
&& mysql_install_db --user=mysql \    /* 2. install database                  */
&& sh -c 'mysqld_safe& sleep 1' \     /* 3. Start mysql for password changing */
&& mysqladmin -u root password 'root' /* 4. set arbitrary root password       */