kill `cat /mysql-data-directory/host_name.pid`
vim /tmp/mysql-init
для версии 5.7.6 и более новой
ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass';
для версии 5.7.5 и более старой
SET PASSWORD FOR 'root'@'localhost' = PASSWORD('MyNewPass');
mysqld_safe --init-file=/tmp/mysql-init
rm -f /tmp/mysql-init