Change the Passwords
Don’t forget to change the passwords for the root and unknown users:
/opt/mysql/mysql/bin/mysqladmin -u root password 'new-password'
/opt/mysql/mysql/bin/mysqladmin -u root -h unknown password 'new-password'
Alternatively you can run:
which will also give you the option of removing the test databases and anonymous user created by default. This is strongly recommended for production servers.