This is for CentOS6
Install EPEL repositories
$ RPMNAME=$(wget -qO- http://mirrors.kernel.org/fedora-epel/6/`uname -i`/ |grep epel |grep rpm |while read i ; do expr "$i" : '.*href="\(.*\)">epel.*'; done) $ rpm -Uvh http://mirrors.kernel.org/fedora-epel/6//`uname -i`/$RPMNAME
Install RBEL repositories
$ rpm -Uvh http://rbel.frameos.org/rbel6
Install Chef Server
$ yum -y --nogpgcheck install rubygem-chef-server
Login to the Web Administration Page
Now login to http://your-chef-server:4040
user: admin password: chef321go