How to Install ‘Varnish’ (HTTP Accelerator)

Install ‘Varnish’

On Debian and Ubuntu

aptitude update && aptitude install varnish

On RHEL, CentOS and Fedora

yum update && yum install varnish

Enter the following command to display the version of Varnish you are running

varnishd -V

Enable it to start on boot

On Debian, Ubuntu
service varnish start
service varnish status
chkconfig --level 345 varnish on
On CentOS/RHEL 7.x and Fedora 21
systemctl start varnish
systemctl status varnish
system enable varnish

Source
Install Varnish
Configure and use Varnish
How to Install ‘Varnish’ (HTTP Accelerator) and Perform Load Testing Using Apache Benchmark