> systemctl stop mysqld.service

> systemctl set-environment MYSQLD_OPTS="--skip-grant-tables"

> systemctl start mysqld.service
> mysql -uroot

mysql> USE mysql
mysql> ALTER USER "root"@"localhost" IDENTIFIED BY "MyNewPassword";
mysql> FLUSH PRIVILEGES;
mysql> quit

> systemctl stop mysqld
> systemctl unset-environment MYSQLD_OPTS

> systemctl start mysqld

> mysql -uroot -p