can't install DB with the command: mysql_install_db --user=mysql

The Error: Installation of system tables failed! Examine the logs in
/var/log/mariadb/mariadb.log or /var/lib/mysql for more information.

The problem could be conflicting information in an external
my.cnf files. You can ignore these by doing:

shell> /usr/bin/mysql_install_db --defaults-file=~/.my.cnf

You can also try to start the mysqld daemon with:

shell> /usr/libexec/mysqld --skip-grant-tables --general-log &

and use the command line tool /usr/bin/mysql
to connect to the mysql database and look at the grant tables:

shell> /usr/bin/mysql -u root mysql
mysql> show tables;

Try 'mysqld --help' if you have problems with paths. Using
--general-log gives you a log in /var/lib/mysql that may be helpful.

The latest information about mysql_install_db is available at
https://mariadb.com/kb/en/installing-system-tables-mysql_install_db
You can find the latest source at https://downloads.mariadb.org and
the maria-discuss email list at https://launchpad.net/~maria-discuss

Please check all of the above before submitting a bug report
at http://mariadb.org/jira