Punch clock for debugging apache storm
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The document proposes a "Punch Clock" concept to help debug Apache Storm transactional topologies. A Punch Clock would record when batches of tuples enter and exit spouts and bolts. Each spout/bolt would have a Punch Card ID to track the batch. Punching in would add the ID to a data structure, punching out would remove it. This would help identify batches stuck in specific spouts/bolts on hosts. It could be exposed via JMX to aggregate data across worker JVMs running the spouts/bolts. The goal is to determine batch flow through the topology and find any that are stuck.
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Punch clock for debugging apache storm
- 1. Punch clock for Apache storm <just an idea>
- 2. Punch clock (a.ka. time clock)
- 3. Punch clock (a.ka. time clock) ● You have a card per person.
- 4. Punch clock (a.ka. time clock) ● You have a card per person. ● The person punches IN with the card when he/she enters the office.
- 5. Punch clock (a.ka. time clock) ● You have a card per person. ● The person punches IN with the card when he/she enters the office. ● The person punches OUT with the card when he/she leaves the office.
- 6. Punch clock (a.ka. time clock) ● You have a card per person. ● The person punches IN with the card when he/she enters the office. ● The person punches OUT with the card when he/she leaves the office. ● The punch clock records the time of entry/exit on the card
- 8. Motivation To Find out … 1. When did the Person enter / exit the office ?
- 9. Motivation To Find out … 1. When did the Person enter / exit the office ? 2. Who is still in office ?
- 10. Change of Context …
- 11. “Apache Storm” Tuples going In & Out of Spouts/Bolts
- 12. Motivation Debugging Apache Storm* * Debugging Storm Transactional Topologies
- 14. Debugging Transactional Topologies 1. Spout emits a batch of data(tuples) which forms a transaction.
- 15. Debugging Transactional Topologies 1. Spout emits a batch of data(tuples) which forms a transaction. 2. Every Bolt in the topology processes that batch of data (tuples).
- 16. Motivation To Find out …
- 17. Motivation To Find out … 1. When did the batch enter/exit the Spout/Bolt ?
- 18. Motivation To Find out … 1. When did the batch enter/exit the Spout/Bolt ? 2. Which batch is still in the Spout/Bolt? i.e. are any batches STUCK ?
- 19. Motivation To Find out … 1. When did the batch enter/exit the Spout/Bolt ? 2. Which batch is still in the Spout/Bolt? i.e. are any batches STUCK ? a. On which host are they stuck ? b. In which Spout/Bolt are they stuck ?
- 21. Possible Solution(s): Add a log statement before and after the critical section.
- 22. Possible Solution(s): Add a log statement before and after the critical section. log.info(“Inserting data into database ….”); // ← entering datasource.insert(table, tuples); // ←the real work log.info(“Inserted data into database.”); //← exiting
- 23. Possible Solution(s): Add a log statement before and after the critical section. log.info(“Inserting data into database ….”); // ← entering datasource.insert(table, tuples); // ←the real work log.info(“Inserted data into database.”); //← exiting ------------------------------------------------------------------ Cons: Logs distributed over multiple hosts, need to aggregate logs. needs a bit of work, Elastic Search Kibana ?
- 24. Possible Solution(s): Use http://riemann.io/index.html This was Suggested by my friend angad. I have not looked at this though.
- 25. My Idea Batch of Tuples Punch IN and Punch Out in a bolt / spout.
- 26. My Idea Batch of Tuples Punch IN and Punch Out in a bolt / spout. Punch In - Put into hashmap (or any other suitable data structure) Punch Out - Remove from hashmap (or any other suitable data structure)
- 27. My Idea: Batch of Tuples Punch In and Punch Out in a spout. In the emitBatch of Transactional Spout: PunchClock.getInstance().punchIn(punchCardId); // ←Punch In collector.emit(tuples); // ←Emit tuple(s) PunchClock.getInstance().punchOut(punchCardId); // ←Punch Out
- 28. Batch of Tuples Punch IN and Punch Out in a bolt . In the prepare method of Transactional Bolt: punchCardId ="Bolt__"+Thread.currentThread().getId()+"__"+System.currentTimeMillis(); // ←Create Punch Card for txn In the execute method of Transactional Bolt: PunchClock.getInstance().punchIn(punchCardId); // ← Punch In In the finishBatch method of Transactional Bolt: PunchClock.getInstance().punchOut(punchCardId); // ← Punch Out My Idea:
- 29. Yes, but it’s a simple Put / Remove call to a hashmap. When compared to logging it’s cheaper Is it intrusive ?
- 30. Punch Clocks
- 31. Punch Clocks ● Spouts / Bolts housed in a storm worker jvm.
- 32. Punch Clocks ● Spouts / Bolts housed in a storm worker jvm. ● One Punch Clock per JVM.
- 33. Punch Clocks ● Spouts / Bolts housed in a storm worker jvm. ● One Punch Clock per JVM. ● Since we have multiple JVM we have multiple Punch Clocks.
- 34. Punch Clocks ● Spouts / Bolts housed in a storm worker jvm. ● One Punch Clock per JVM. ● Since we have multiple JVM we have multiple Punch Clocks. ● Batches move across storm workers & we have multiple JVM, ○ We need to aggregate the data across Punch Clocks. ○ Expose Punch Clock via JMX.
- 36. demo: