Install MariaDB without password prompt in Ubuntu
A mixture of the mysql/mariadb-Nameing has worked for me:

export DEBIAN_FRONTEND=noninteractive
debconf-set-selections &lt;&lt;&lt; 'mariadb-server-5.5 mysql-server/root_password password rootpass'
debconf-set-selections &lt;&lt;&lt; 'mariadb-server-5.5 mysql-server/root_password_again password rootpass'