For example my latest drama with rocks was that I just needed subversion, to convert one of my BinBase images to a development image for BinBase.
Little did I know, that in the rocks 5.4 version, the installer fails to provide you with the base repository. Quality control anyone?
Anyway, to get your yum to work, as exspected. Just open your
file and add the following section
name=CentOS-$releasever - Base
at the end of the file and than you can install subversion like always using:
yum -y install subversion