Last description at (Working in progress): http://acacha.org/mediawiki/index.php/Fog#FOGDHCPDUpdater_Service
This service is based on FOGImageReplicator. The goal of DHCPDUpdater is to create a section in DHCPD Server configuration file with an static assigment of IPs (based on MAC).
This service is by default executed every 600 seconds (10 minuts). First time it is executed, the service obtains information of all hosts in fog database and creates a section in DHCPD server configuration file (by default /etc/dhcp3/dhcpd.conf) and reloads DHCP server . Next execution only reload DHCP server if file dhcpd.conf is changed (be careful if you edit dhcp server, you previously have to stop this service if you don't want automatica reloads every 10 minutes).
IMPORTANT NOTE: This service doesn't change any previous DHCP server configuration. It only changes an specific section of file. The section have a Header and a
footer taht you can configure at service/etc/config.php.