How to disable GDM user list in Fedora 21 (GNOME 3)

If you need to disable the default user list in Fedora 21, the approach is slightly different than it was before (again)…

You have to run this command in the terminal (within running X session) as root:

[root@universe ~]# sudo -u gdm gsettings set org.gnome.login-screen disable-user-list true

This change will take effect after the next reboot or after gdm restart, and user will have to input their username in order to log in.