Scott, as far as I can tell, CentOS does have the GlusterFS packages, they are listed here:
glusterfs-3.4.0.36rhs-1.el6.x86_64.rpm 24-Nov-2013 13:31 1.8M
glusterfs-api-3.4.0.36rhs-1.el6.x86_64.rpm 24-Nov-2013 13:31 44K
glusterfs-api-devel-3.4.0.36rhs-1.el6.x86_64.rpm 24-Nov-2013 13:31 19K
glusterfs-devel-3.4.0.36rhs-1.el6.x86_64.rpm 24-Nov-2013 13:31 100K
glusterfs-fuse-3.4.0.36rhs-1.el6.x86_64.rpm 24-Nov-2013 13:31 90K
glusterfs-libs-3.4.0.36rhs-1.el6.x86_64.rpm 24-Nov-2013 13:31 226K
glusterfs-rdma-3.4.0.36rhs-1.el6.x86_64.rpm 24-Nov-2013 13:31 44K