Ubuntu 18.04 mysql install
sudo apt install mysql-server
sudo mysql -u root
mysql> FLUSH PRIVILEGES;
mysql> use mysql;
mysql> UPDATE user SET plugin="mysql_native_password" WHERE User='root';
mysql> UPDATE user SET authentication_string=PASSWORD("***") WHERE User='root';
# *** is your password
# *** is your password
mysql>UNINSTALL COMPONENT "file://component_validate_password";
mysql> quit
sudo service mysql restart
mysql> quit
sudo service mysql restart