To enable gnome for proxmox the process is very simple. First setup proxmox, and then run the following shell commands in proxmox
tasksel install desktop gnome-desktop #Then enable gnome on startup sudo systemctl set-default graphical.target #Now disable gdm-password for root login check sed -i 's/.*pam_succeed_if/#&/' /etc/pam.d/gdm-password reboot #Now login with console !