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Not Invented Here Syndrome and Dark Debt: The PagerDuty Story
AISH RAJ DAHAL
Not Invented Here Syndrome and Dark Debt: The PagerDuty Story AISH - - PowerPoint PPT Presentation
Not Invented Here Syndrome and Dark Debt: The PagerDuty Story AISH - - PowerPoint PPT Presentation
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
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Not Invented Here Syndrome
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–The English Wikipedia (2018)
“… 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…”
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Dark Debt
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– Woods DD, STELLA: Report from the SNAFU catchers Workshop on Coping With Complexity. 2017
“….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….”
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Comparison to technical debt
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Build vs Buy: The age old question
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Can building instead of buying lead to dark debt ?
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Where does Not Invented Here syndrome come in the mix ?
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WorkQueue
Section II
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October 24, 2011
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WorkQueue
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Background
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High Availability
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Durability
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High Scalability
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Decent Queryability
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Flexible Schema
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Backups
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Synchronous Replication
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What were the options then?
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Kafka?
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Other options were actually considered
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Result: WorkQueue v1
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But it did not stop there…
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Host based partitioning
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Fair partitioning
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Time based row bucketing
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…there were more services using WorkQueue
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In the meanwhile…
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Other distributed queues like Kafka gained popularity
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PaaS based queues made their presence felt
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Cassandra’s API changed*
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Thrift RPC fell out of favor within the company
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WorkQueue’s nature and widespread use was slowly turning into dark debt.
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Lessons learnt
Section III
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Dark debt is a product of complexity
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The development and use of in-house software for a task is not an indication dark debt
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However, the proliferation of such special purpose software to
- ther areas is often an indication of Not Invented Here syndrome
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Not Invented Here syndrome is an indication of dark debt
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Proactive evaluation of past custom solutions before proliferation could help alleviate some of the problems
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Unless there is a really strong case for it, don’t go with build*
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When in doubt chose simplicity over complexity
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The past, the present and the future
Epilogue
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Official support for WorkQueue was ended in 2016
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Cassandra based WorkQueue’s usage in PagerDuty has significantly reduced since 2017
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–Edsger W. Dijkstra
“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.”
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