How to Install Varnish 3 On CentOS by lifeLinux on November 3, 2011 Varnish is an HTTP accelerator designed for content-heavy dynamic web sites. In contrast to other HTTP accelerators, such as Squid, which began life as a client-side cache, or Apache and nginx, which are primarily origin servers, Varnish was designed from the ground up as an HTTP accelerator. Installation on CentOS / RedHat Varnis