Varnish is a web application accelerator. You install it in front of your web application and it will speed it up significantly.
To install varnish on CentOS 6, Install the Varnish Yum repository
rpm -Uvh http://repo.varnish-cache.org/redhat/varnish-3.0/el5/noarch/varnish-release/varnish-release-3.0-1.noarch.rpm
Now Install varnish
yum install varnish
Enable varnish at startup
chkconfig varnish on
Now start varnish
service varnish start
To install varnish on CentOS 6, Install the Varnish Yum repository
rpm -Uvh http://repo.varnish-cache.org/redhat/varnish-3.0/el5/noarch/varnish-release/varnish-release-3.0-1.noarch.rpm
Now Install varnish
yum install varnish
Enable varnish at startup
chkconfig varnish on
Now start varnish
service varnish start