1. Highly Available Drupal
on a Raspberry Pi Cluster
Jeff Geerling, php[tek] 2016
(geerlingguy)
http://www.shockinglydelicious.com/dorothys-fresh-raspberry-pie-recipe/

2. http://www.shockinglydelicious.com/dorothys-fresh-raspberry-pie-recipe/

3. The Big Question
Can you run a Fortune 500
website in your basement?

4. Another Question
Why would you?

5. Gateway 2000 486 PC, RedHat Linux 6
1999

6. Whistle Interjet, running FreeBSD 4

7. Raspberry Pi 1 model B

9. Problems with one Pi

10. Problems with one Pi
• No redundancy

11. Problems with one Pi
• No redundancy
• microSD card reliability

12. Problems with one Pi
• No redundancy
• microSD card reliability
• No database backup

13. Problems with one Pi
• No redundancy
• microSD card reliability
• No database backup
• Limited resources

14. • No redundancy
• microSD card reliability
• No database backup
• Limited resources
High Availability
Single Pi Multi Pi

15. • Easy redundancy• No redundancy
• microSD card reliability
• No database backup
• Limited resources
High Availability
Single Pi Multi Pi

16. • Easy redundancy
• Can hot-swap a Pi
• No redundancy
• microSD card reliability
• No database backup
• Limited resources
High Availability
Single Pi Multi Pi

17. • Easy redundancy
• Can hot-swap a Pi
• Hot database backup
• No redundancy
• microSD card reliability
• No database backup
• Limited resources
High Availability
Single Pi Multi Pi

18. • Easy redundancy
• Can hot-swap a Pi
• Hot database backup
• Each server optimized
• No redundancy
• microSD card reliability
• No database backup
• Limited resources
High Availability
Single Pi Multi Pi

19. 2014

22. CPU 20 cores / 6 GHz
RAM 5 GB
Storage 80 GB microSD
Network 10/100 over Gig
www.pidramble.com
Raspberry Pi Cluster

24. Problem
How do you wrangle all these Pis?

25. “Configuration management for humans.”

26. “Configuration management for humans.”
___________
< And cows! >
-----------
^__^
(oo)_______
(__) )/
||----w |
|| ||

27. Source: https://flic.kr/p/nkcFoU

29. Demo

30. How did it do?

31. Benchmarks
Benchmark Standard
Uptime 99.95%
Max page loads/sec 1000
Power Consumption 0.5 Gflops/watt

32. Benchmarks - Uptime
(as measured by Server Check.in)

33. Benchmarks - Performance
Nginx, Cached Page 3160 req/s
Drupal, Cached Page 34 req/s
Drupal, Uncached Page 12 req/s
For comparison:
• My MacBook Air: 6x faster
• DigitalOcean droplets: 10x faster

34. Benchmarks - Power
Raspberry Pi 3 260 mA
Raspberry Pi 2 220 mA
Raspberry Pi Zero 80 mA
(power draw at idle)

35. Benchmarks - Power
Raspberry Pi 2 0.15 Gflops/watt
For comparison:
• Core i7: 0.5 Gflops/watt
Source: http://www.phoronix.com/scan.php?page=article&item=raspberry-pi-burst&num=3

36. *

37. Go Small or Go Home

39. Lessons Learned

40. Lessons Learned
Test one change at a time.
Rinse and repeat.

41. Lessons Learned
Networks are always reliable.

42. Lessons Learned
Networks are always reliable.
NEVER!

43. The Big Question
Can you run a Fortune 500
website in your basement?

44. Resources
• www.pidramble.com
• Jeff Geerling's Blog
• Win the Pi Zero! Subscribe on
www.ansiblefordevops.com