How to install and configure Varnish cache on Ubuntu Linux 16.04 LTS

Here are the steps to install and configure Varnish cache on Ubuntu 16.04 LTS:

1. Install Varnish:

sudo apt-get update
sudo apt-get install varnish

1. Edit the default Varnish configuration:

sudo nano /etc/default/varnish

• Change the DAEMON_OPTS variable to listen on port 80:

DAEMON_OPTS="-a :80 n -T localhost:6082 n -f /etc/varnish/default.vcl n -S /etc/varnish/secret n -s malloc,256m"

1. Configure Varnish to use a backend server:

sudo nano /etc/varnish/default.vcl

• Replace the contents of the file with the following:

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

• Replace 127.0.0.1 with the IP address of your backend server, and replace 8080 with the port number of your backend server.

1. Restart Varnish:

sudo service varnish restart

1. Test Varnish by sending a request to the Varnish cache on port 80:

curl http://localhost

If the request returns a response from the backend server, Varnish is working correctly.

Note: These instructions are a basic guide for setting up Varnish. You may need to make additional configuration changes based on your specific requirements.