There seems to be no definitive solution for this, either in Ubuntu's official documentation or other sources of information.
In some places systemctl is suggested but I think Ubuntu does not support it for the moment.
Other suggestions include manually creating the links, but I feel there should be a better way. On the other hand there are graphical programs to achieve this, but what about servers without GUI?
In Fedora I don't think this is an issue. You can use chkconfig to add/remove a service from the startup sequence.
The equivalent of chkconfig for Ubuntu seems update-rc.d, but:
# update-rc.d modemmanager enable
update-rc.d: /etc/init.d/modemmanager: file does not exist
Since Ubuntu is the most used GNU/Linux distribution, I believe there must be a way to do this in the command line with a specific command.
