How to Install Varnish 4 on CentOS 7

Varnish is a proxy and cache, or HTTP accelerator, designed to improve performance for busy, dynamic websites. By redirecting traffic to static pages whenever possible, varnish reduces the number of dynamic page calls, thus reducing the load.

• These instructions are intended specifically for installing the Varnish on CentOS 7.
• I’ll be working from a Liquid Web Self Managed CentOS 7 server, and I’ll be logged in as root.

Varnish is part of Extra Packages for Enterprise Linux (EPEL), which is a community repository of non-standard packages for the RHEL distribution. First, we’ll install the EPEL repository, for directions see How to enable EPEL repository?

First, you’ll follow a simple best practice: ensuring the list of available packages is up to date before installing anything new.

yum -y update

At this point, installing Varnish is as simple as running just one command:

yum -y install varnish

To configure varnish to start at boot, run the following command:

systemctl enable varnish

To start varnish, run the following command as root:

systemctl start varnish

To check the status of varnish, run the following command as root:

systemctl status varnish

Check the version of Varnish that is running:

varnishd -V

Varnish is configured to listen on port 6081 by default. It expects your web server to be local, or on the same serve,r and listening on port 8080.

A basic and default configuration file can be found at:

/etc/varnish/default.vcl

An example configuration can be found in example.vcl:

/usr/share/doc/varnish-4.0.1/example.vcl

For a refresher on editing files with vim see: New User Tutorial: Overview of the Vim Text Editor

To view or edit example.vcl:

vim /usr/share/doc/varnish-4.0.1/example.vcl