not invented here syndrome and dark debt the pagerduty
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Not Invented Here Syndrome and Dark Debt: The PagerDuty Story AISH RAJ DAHAL Section I Why are we here ? Not Invented Here Syndrome the tendency towards reinventing the wheel based on the belief that in-house developments are


  1. Not Invented Here Syndrome and Dark Debt: The PagerDuty Story AISH RAJ DAHAL 


  2. Section I Why are we here ?

  3. Not Invented Here Syndrome

  4. “… the tendency towards reinventing the wheel based on the belief that in-house developments are inherently better suited, more secure, more controlled, quicker to develop, and incur lower overall cost than using existing implementations…” –The English Wikipedia (2018)

  5. Dark Debt

  6. “….Dark debt was named to draw a parallel with dark matter. Dark matter has detectable effects on the world but cannot be seen or detected directly….Dark debt is found in complex systems and the anomalies it generates are complex system failures….Dark debt is not recognizable at the time of creation. Its impact is not to foil development but to generate anomalies….” – Woods DD, STELLA: Report from the SNAFU catchers Workshop on Coping With Complexity. 2017

  7. Comparison to technical debt

  8. Build vs Buy: The age old question

  9. Can building instead of buying lead to dark debt ?

  10. Where does Not Invented Here syndrome come in the mix ?

  11. Section II WorkQueue

  12. October 24, 2011

  13. WorkQueue

  14. Background

  15. High Availability

  16. Durability

  17. High Scalability

  18. Decent Queryability

  19. Flexible Schema

  20. Backups

  21. Synchronous Replication

  22. What were the options then?

  23. Kafka?

  24. Other options were actually considered

  25. Result: WorkQueue v1

  26. But it did not stop there…

  27. Host based partitioning

  28. Fair partitioning

  29. Time based row bucketing

  30. …there were more services using WorkQueue

  31. In the meanwhile…

  32. Other distributed queues like Kafka gained popularity

  33. PaaS based queues made their presence felt

  34. Cassandra’s API changed*

  35. Thrift RPC fell out of favor within the company

  36. WorkQueue’s nature and widespread use was slowly turning into dark debt.

  37. Section III Lessons learnt

  38. Dark debt is a product of complexity

  39. The development and use of in-house software for a task is not an indication dark debt

  40. However, the proliferation of such special purpose software to other areas is often an indication of Not Invented Here syndrome

  41. Not Invented Here syndrome is an indication of dark debt

  42. Proactive evaluation of past custom solutions before proliferation could help alleviate some of the problems

  43. Unless there is a really strong case for it, don’t go with build*

  44. When in doubt chose simplicity over complexity

  45. Epilogue The past, the present and the future

  46. Official support for WorkQueue was ended in 2016

  47. Cassandra based WorkQueue’s usage in PagerDuty has significantly reduced since 2017

  48. “Simplicity is a great virtue but it requires hard work to achieve it and education to appreciate it. And to make matters worse: complexity sells better.” –Edsger W. Dijkstra

  49. 谢谢 ありがとう مكل اركش Thank You Merci धन्रवाद Gracias Danke Asante @aishrajdahal

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