Implement varnish with apache, and drupal

[jeff1evesque]

We will implement varnish with apache, as well as integrate it with drupal. Specifically, we will integrate the drupal varnish module, with the following varnish configurations:

• https://devops.profitbricks.com/tutorials/install-and-configure-varnish-with-apache-on-centos-7/

Note: this issue is intended to resolve the invalid duplicate #144.

[jeff1evesque]

Unfortunately, varnish cannot run on https, which is a problem since we are forwarding all http requests to https. So, we need to implement the following solution model:

Note: in our case the Backend Cluster should just be a single apache webserver instance. However, we can replace the above nginx implementation, for the ssl termination proxy, with the following alternatives:

• HAProxy
• Squid
• Apache

Note: if nginx is the chosen solution, then the corresponding approach would be as follows:

• configure apache to listen on port 8080 for example, and nginx as reverse proxy listening on 80 & 443 and passing traffic to port 8080