Automated installation is available as well aside of manual pairing.
A cloud-init of the following form can be supplied as a datasource (CDROM, cos.setup bootarg):
#cloud-config
install:
device: "/dev/sda"
reboot: true
poweroff: true
auto: true # Required, for automated installations
c3os:
network_token: ....
# extra configuration
which will drive the installation automatically on first boot.
The installer will kick in automatically and reboot/poweroff if specified. Note, to trigger the automatic installation the offline field must be enabled.