How to change data location on Ubuntu
I've done that on ubuntu, I don't use apparmor but these are the settings I've changed, all under [mysqld] (I think mysql_safe also uses these settings)

datadir = /mysql_data
innodb_data_home_dir = /mysql_data
innodb_log_group_home_dir = /mysql_data


I've also put my log files there but that is not needed.