Installed Percona Server / Mysql 5.7 and cannot start without root password.
To fix this:
Make sure your data dir is empty. mysqld --initialize-insecure --datadir=/path-to-datadir --user=youruserDone. Now you have root user with no password
Make sure your data dir is empty. mysqld --initialize-insecure --datadir=/path-to-datadir --user=youruserDone. Now you have root user with no password