The Essex OpenStack release is being packaged for Debian GNU/Linux wheezy upcoming release. Each new release of a package is committed to a git repository ( the keystone is an example ) by a member of the OpenStack Debian GNU/Linux release team and uploaded to Debian GNU/Linux : a process that can require a few weeks before it is available in the Debian GNU/Linux worldwide mirror sites. In the meantime, a temporary repository is setup with packaging-farm to host the packages being processed so that they can be used immediately by adding the following line to the source list of packages.
deb http://wheezy.the.re/packaging-farm/openstack/gnulinux/debian wheezy main