Nova uses a configuration file containing flags located in /etc/nova/nova.conf. You can get the most recent listing of avaialble flags by running nova-(servicename) --help, for example:
A script for generating a sample nova.conf file is located in <nova_root>/tools/conf/run.sh. This script traverses through the source code and retrieves information of every option that is defined. A file named nova.conf.sample will be placed in the same directory.
The OpenStack wiki has a page with the flags listed by their purpose and use at http://wiki.openstack.org/FlagsGrouping.