gistfile1.txt

   CGroup: /system.slice/mariadb.service
           └─2454 /usr/sbin/mysqld
+ sudo journalctl -lxn 100 --no-pager
+ grep mysqld
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: 
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: Installation of system tables failed!  Examine the logs in
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: /var/lib/mysql for more information.
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: 
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: The problem could be conflicting information in an external
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: my.cnf files. You can ignore these by doing:
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: 
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]:     shell> /usr/bin/mysql_install_db --defaults-file=~/.my.cnf
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: 
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: You can also try to start the mysqld daemon with:
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: 
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]:     shell> /usr/sbin/mysqld --skip-grant-tables --general-log &
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: 
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: and use the command line tool /usr/bin/mysql
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: to connect to the mysql database and look at the grant tables:
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: 
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]:     shell> /usr/bin/mysql -u root mysql
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]:     mysql> show tables;
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: 
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: Try 'mysqld --help' if you have problems with paths.  Using
Apr 01 12:46:22 debian-9-stretch-amd64 mysqld_safe[1894]: --general-log gives you a log in /var/lib/mysql that may be helpful.