ubuntu에서 mysql 5.7 또는 mariadb 10 이상 root password reset

# Stop MySQL
sudo service mysql stop

# Make MySQL service directory.
sudo mkdir /var/run/mysqld

# Give MySQL user permission to write to the service directory.
sudo chown mysql: /var/run/mysqld

# Start MySQL manually, without permission checks or networking.
sudo mysqld_safe --skip-grant-tables --skip-networking &

# Log in without a password.
mysql -uroot mysql

Update the password for the root user.

UPDATE mysql.user SET authentication_string=PASSWORD('YOURNEWPASSWORD'), plugin='mysql_native_password' WHERE User='root' AND Host='%';
EXIT;

mysql 재시작

# Turn off MySQL.
sudo mysqladmin -S /var/run/mysqld/mysqld.sock shutdown

# Start the MySQL service normally.
sudo service mysql start