Drupal 7 + HTTPS + Nginx + Varnish + Apache + Boost + APC + Securepages + Drupal

If you happen to develop large sites in Drupal, you might fall upon a case like this one, where different servers (namely at least one reverse proxy and one web server) interact, causing a series of chain reactions every time you change something. It might be frustrating, at times, to try and boost a coordinated system like this, and end up getting your users frustrated because part of it doen't work, when the rest (the part that *does* work) is super-fast.

Munin nginx_status fails on HTTPS

This must appear in one opportunity in 1000, but it happened to me, so I bet it might have just happened to you... Munin is great, Nginx is great, and SSL is great, but when you mix all of them together, you might get some frustrating behaviour. If you don't know it already, you can test the results of a Munin plugin on Debian-based systems with the command
sudo munin-run [plugin]
For example, if your nginx_status graph in the Munin web interface is empty, you can try
sudo munin-run nginx_status
The name of the plugin will auto-complete with the TAB key, with any plugin

Renew expired self-signed SSL certificate

For some reason, it might be very difficult to find information on how to renew a self-signed certificate. This is a nice (and short) explanation: http://linux.togaware.com/survivor/Renew_SSL.html. Please note that a .pem file is in fact (as you can guess from the small guide) a combined .key and .crt. In short and only for the purpose of not loosing this reference (as has happened many times before with sites referenced on this blog), here is the procedure (just adapt to your case, i.e.