How to Install Varnish Cache with Apache on CentOS 7

Posted in Windows Servers on Oct 09, 2020

How to Install Varnish Cache with Apache on CentOS 7

Varnish is a proxy server focused on HTTP caching. It's designed as an HTTP accelerator and can act as reverse proxy for your web server Apache or Nginx. Varnish has been used for high-profile and high-traffic websites,

Step 1 - Install and configure Apache on CentOS 7

We will install Apache/httpd web server from the CentOS 7 repository, and then configure the server that will be running on port 8080. Install Apache/httpd using the yum command below.

yum -y install httpd

After the installation is complete, start the httpd service and enable it to run at system boot using the commands below.

systemctl start httpd
systemctl enable httpd

So the httpd service is now running. Check it using netstat or curl command as shown below.

netstat -plntu
curl -I localhost

Step 2 - Configure Apache on port 8080

Vi /etc/httpd/conf/httpd.conf

Change the default port 80 to 8080 on the 'Listen' line.

Listen 8080

Now test the configuration and make sure there is no error. Then restart the apache/httpd service.

apachectl configtest

Step 3 - Install Varnish on CentOS 7

Install EPEL repository using the following command.

yum -y install epel-release

Now install Varnish from the EPEL repository using yum command below.

yum -y install varnish

After the installation is complete, start Varnish and add it to launch at system boot using the systemctl commands below

systemctl start varnish
systemctl enable varnish

Step 4 - Configure Varnish as a reverse proxy for Apache

So Varnish is installed, and now we will configure it as a reverse proxy for the Apache web server. Varnish will run on HTTP port 80 by default. Go to the Varnish configuration directory and edit the default configuration in 'default.vcl'.

cd /etc/varnish
vim default.vcl

Define the default backend section. We are using Apache web server running on port 8080, so the configuration as below.

backend default {
     .host = "127.0.0.1";
     .port = "8080";
 }

Step 5 Save and exit. Now restart Varnish

Next, configure Varnish to run with HTTP port 80. Edit the 'varnish.params' file present in the Varnish configuration directory. In this file, change the value of the 'VARNISH_LISTEN_PORT' line to HTTP port 80. VARNISH_LISTEN_PORT=80