Installing Varnish on CentOS 7

Varnish is a caching HTTP reverse proxy that improves the performance of websites by storing a copy of the content served by the web server. When a user requests a page, Varnish retrieves it from the cache instead of forwarding the request to the web server, reducing the response time and server load.

To install Varnish on CentOS 7, follow the steps below:

1. Update the system:

   sudo yum update

2. Install the EPEL repository:

   sudo yum install epel-release

3. Install Varnish:

   sudo yum install varnish

4. Start and enable Varnish service:

   sudo systemctl start varnish sudo systemctl enable varnish

5. Configure Varnish to listen on port 80 (default HTTP port) by editing the default Varnish configuration file:

   sudo vi /etc/varnish/default.vcl

   Find the line that starts with "backend default" and replace "127.0.0.1" with the IP address or hostname of your web server.

6. Restart Varnish to apply the configuration changes:

   sudo systemctl restart varnish

After installing and configuring Varnish, it will act as an intermediary between the client and the web server. Clients will make requests to Varnish, which will serve cached content if available or forward the request to the web server if necessary.

Note: It's important to configure your web server to listen on a different port, such as 8080, and update any firewall rules accordingly to allow traffic on that port.