Silo-Based Architectures for High Availability Applications @PhpUk2017

High availability is becoming a de-facto requirement of today's applications. Customer-facing IT failures mean directly losing customer revenue and trust, as users have grown accustomed to easily switching service providers for more reliable ones. Lack of internal systems availability block employee productivity and add to the financial burden. Thus, it is critical to have a healthy, performant, resilient IT structure serving as a backbone of conducting your business. But there are no textbook solutions to achieving five 9s availability. Data redundancy, computing clusters, load balancing, fail-over mechanisms, each of these individually addresses one potential issue, but none treats systems in your organisation holistically for maximising business revenue. Silos are a clever method of grouping servers in such a way that they can be scaled both horizontally and vertically, depending on the actual application needs. Most importantly, it frees you from over-optimizing the architecture upfront, by allowing fine adjustments easy to integrate in your Agile workflow.

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1. FOR HIGH AVAILABILITY APPLICATIONS SILO-BASED ARCHITECTURES Georgiana Gligor / Tekkie Consulting / @gbtekkie February 2017 PHP UK
2. 2 Georgiana Gligor ✤ Geek. Mother. Do-er. ✤ Crafting enterprise apps ✤ Large-Scale Application Architect ✤ PHP Cluj Meetup Organiser ✤ Systems Engineering PhD Student @gbtekkie gb@tekkie.ro
4. 4 https://youtu.be/MQm5BnhTBEQ
5. 5 advantages and disadvantages AGENDA silos: a possible approach the need for high availability what is high availability (HA)?
6. Software industry is built around anticipating change. 6
7. TYPICAL APPLICATION
8. 8 SIMPLE ARCHITECTURE
11. master Frontend Business Logic Frontend Frontend Browser internet Load balancer slave reads writes 11 ADJUSTING
12. master Frontend Business Logic Frontend Frontend Browser internet Load balancer slave reads writes 12 ADJUSTING redundancy
13. master Frontend Business Logic Frontend Frontend Browser internet Load balancer slave reads writes 13 ADJUSTING resilience
14. 14 TYPICAL LAYERING
15. 15 APPLICATION ARCHITECTURE
16. HIGH AVAILABILITY
17. 17 AVAILABILITY Ability to access the system: ✤ retrieve information ✤ alter information ✤ send new data
18. https:/ /flic.kr/p/dkasBz
19. 19 THE 9s DANCE Uptime Downtime (per year) 90.000 % 36.50 days one nine 99.000 % 3.65 days two nines 99.900 % 8.76 hrs three nines 99.950 % 4 hrs 23 mins 99.990 % 52.56 mins four nines 99.999 % 5.26 mins five nines
20. 20 THE 9s DANCE Uptime Downtime (per year) 90.000 % 36.50 days 99.000 % 3.65 days 99.900 % 8.76 hrs 99.950 % 4 hrs 23 mins Amazon SLA 99.990 % 52.56 mins four nines 99.999 % 5.26 mins five nines
21. 21 IMPACT $ 144,000 / hour 3600 $ 40 / sec * =
22. 22 USER BEHAVIOUR amazon facebook youtube Alexa Rank 6 3 2 daily time on site 12:07 mins 19:27 mins 23:44 mins daily pageviews / visitor 11.83 9.38 12.84 bounce rate 21% 29% 33%
23. 23 HIGH AVAILABILITY TRIANGLE cost complexity risk
24. 24 DOWNTIME ✤ scheduled ➡ you ✤ unscheduled ➡ you ➡ others
25. 25 HAPPENS TO THE BEST
26. 26 MICHAEL JACKSON
27. HA SYSTEM CHARACTERISTICS
28. https://flic.kr/p/quMmFw NO SINGLE POINT OF FAILURE
29. https://en.wikipedia.org/wiki/Point_of_sale#/media/File:Cash_Registers.JPG RELIABLE CROSSOVER
30. https://flic.kr/p/4S4uDz DETECT FAILURES AS THEY OCCUR
31. 31 HA BEST PRACTICES 1. no single points of failure 2. stateless application design 3. automate infrastructure for consistency & reliability 4. clever monitoring and alerting 5. geographically distribute your machines 6. keep spare capacity to meet increasing demand
32. 32 A man’s got to know his limitations. - Dirty Harry
33. SILOS
34. 34 Departments inside a company don’t work together. - Silo Mentality https://flic.kr/p/7Sp6Wg
35. 35 TRY UPGRADE TO PHP7
36. 36 WHAT IS A SILO? ✤ frontend (e.g. Javascript SPAs) ✤ backend (e.g. PHP services) ✤ cache 1 silo = full setup of servers that deliver the end-to-end functionality
37. 37 WHAT IS A SILO?
38. 38 SILO-BASED ARCHITECTURE
39. 39 MULTIPLE CACHES
40. 40 A/B TESTING
41. 41 GEOGRAPHICAL DISTRIBUTION
42. 42 LIVE UPGRADES
43. 43 ADVANTAGES ✤ reuse familiar technology ✤ real A/B testing ✤ no BHUF requirements ✤ no disruption => brand loyalty ✤ lower Total Cost of Ownership ✤ simplify scalability
44. 44 DISADVANTAGES ✤ needs razor-sharp DevOps team ✤ small increase in hardware costs on kick-off ✤ adds complexity to the monitoring layer ✤ reconsider traceability ✤ different bug reproducing and hunting
45. TAKEAWAYS
47. 47 ✤ build situational awareness with clever monitoring ✤ automate outage detection ✤ powerful A/B testing TAKEAWAYS
48. 48 FURTHER READING ✤ Wikipedia HA page ✤ OpenStack’s HA concepts ✤ Merge Hemo report from FDA ✤ USA Presidential Policy Directive 21 ✤ “Beyond Legacy Code” book ✤ TechCrunch’s summary of sites affected by Michael Jackson’s death ✤ Netflix lessons learned after AWS outage ✤ Netflix Chaos Monkey source code ✤ Brian Adler’s talk on “Architecting for High Availability and Multi-Cloud”
49. ‹#› THANK YOU GEORGIANA GLIGOR @gbtekkie } Affordable quality system architecture. In-house PHP trainings.