From this discussion: http://openstack.redhat.com/forum/discussion/519/puppet-fails-to-set-openvswitch-from-absent-to-present/p1 It's clear that the current error messages from yum when package installation fails are not really good enough. Yum will just say "Nothing to do" which doesn't tell the user what really happened. What we should do is have Packstack catch that sort of error from Yum/Puppet and let the user know that the issue is that the package in question was a dependency and it failed to install for some reason.
*** This bug has been marked as a duplicate of bug 1003959 ***