$ sudo apt-get install software-properties-common
$ sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com 0xcbcb082a1bb943db
$ sudo add-apt-repository 'deb http://ftp.osuosl.org/pub/mariadb/repo/10.2/ubuntu trusty main'
$ sudo apt-get update
$ sudo apt-get install mariadb-server
$ sudo mysql_upgrade
Ref: https://mariadb.com/kb/en/library/installing-mariadb-deb-files/