Varnish is an HTTP accelerator designed for content-heavy dynamic web sites. In contrast to other HTTP accelerators, many of which began life as client-side proxies or origin servers, Varnish was designed from the ground up as an HTTP accelerator.

Performance

While Varnish is designed to reduce contention between threads to a minimum, its performance will only be as good as that of the system's pthreads implementation. Additionally, a poor malloc implementation may add unnecessary contention and thereby limit performance.

When the requested document is in cache, response time is typically measured in microseconds. This is significantly better than most HTTP servers, so even sites consisting mostly of static content will benefit from Varnish.

Software requirements

• WHM/cPanel (11.28+)
• CentOS 5.5
• Apache 2.x

Plugin Features

• Installer for (Varnish, Mod_RPAF)
• Configuration for Varnish Cache to work in Front of Apache
• Configure Apache 2.x to work as Backend Web Server
• Installing Mod_RPAF for Apache 2.x to handle the reverse Proxy IPs
• Advance Varnish Configuration
• Added to WHM Services Manager

Benchmark

• Dual-Core Opteron
• 1GB RAM
• 10GB Disk space
• WordPress 3.0

I've created this blog to share my first cPanel Plugin which will be provide Varnish Installation/Configuration
I will keep updated this blog until I've finished the release version.

hope that I can create something helpful.