Now that you know how to configure a webserver and a load balancer, another commonly used component in an application hosting scenario is a caching server. To do this, we will use Varnish which is a web application accelerator also known as a caching HTTP reverse proxy. Varnish Cache is really, really fast. It typically speeds up delivery with a factor of 300 - 1000x, depending on your architecture.
Steps to manually configure Varnish:
- Ensure system is updated.
- Allow port 80 in the firewall, Varnish needs to run on port 80.
- Install the Varnish package.
- Start and enable the Varnish service.
- In the file /usr/lib/systemd/system/varnish.service you will find a line - " ExecStart=/usr/sbin/varnishd -a :6081 -f /etc/varnish/default.vcl -s malloc,256m" Replace this line with " ExecStart=/usr/sbin/varnishd -a :80 -f /etc/varnish/default.vcl -s malloc,256m "
- Perform a daemon-reload for the new service to be read.
- Copy the new default.vcl to /etc/varnish/default.vcl. Edit your webserver IP in the backend default section.
- Restart the service.
Navigating to the Varnish webserver should redirect you to your webserver. If you open the page console using a browser and check the properties, the request will be shown as delivered using Varnish Cache.
Diagram:
