This page exists to document OpenStack configuration.
Note that the current approach is to use devstack, which is not a good way to learn OpenStack. So much of this document will be about doing a devstack-like configuration for Funtoo.
This document will split OpenStack configuration into each architectural component, describing configuration steps for each component separately.
Devstack uses MySQL as its deployment database. However, it appears that OpenStack as a whole uses SQLAlchemy behind the scenes, which is a re-targetable database API. Thus, it should be possible to use Postgres, etc, by simply using different connection strings. A list of SQLAlchemy connection types can be found on this SQLAlchemy documentation page.
The Glance project provides services for discovering, registering, and retrieving virtual machine images. Glance has a RESTful API that allows querying of VM image metadata as well as retrieval of the actual image.
Glance uses a MySQL database called glance.
SQL connection settings might be stored in a glance configuration file located at /opt/stack/glance/etc/glance-registry.conf. In the devstack installation process, /opt/stack/glance contains a git checkout of the glance software.
The SQL connection configuration string might look something like this:
sql_connection = mysql://glance:email@example.com/glance
More info on glance configuration is available here.
Nova, the compute service, has its SQL connection specified in /etc/nova/nova.conf, using the --sql_connection=connection format. Connection string is identical to Glance. These are all SQLAlchemy connection strings :)