In 2015, after the Raspberry Pi Foundation released the second generation of Raspberry Pi computers, with a 4-core ARM processor (which is more than 6x faster than the processor used in its predecessors), I decided to buy a bunch of them to use for local Ansible testing and for presentation purposes.
The fruit of this effort is the Raspberry Pi Dramble, a 6-node cluster of Raspberry Pi 2 computers that runs a demonstration Drupal 8 website. Software is deployed using Ansible, since it works great with Raspbian out of the box, and my roles on Ansible Galaxy install and configure Nginx (for load balancing and as the web server), PHP, Redis, and MySQL, among other software.
The cluster runs a high-performance/high-availability instance of a Drupal 8 website, and is meant to demonstrate the resiliency of this setup, plus the power and ease of using Ansible to deploy Drupal and other software to multiple servers.
You can view all the code and configuration, along with a detailed Wiki, in the Raspberry Pi Dramble project on GitHub.
Presentations with the Raspberry Pi Dramble:
- 6-node Raspberry Pi 2 cluster
- Cluster controlled through Ansible
- Capable of 2000+ req/s
- Runs Drupal w/ Nginx, PHP, Redis, and MySQL