HBase is used to serve online facing traffic in Pinterest. It means no downtime is allowed. However, we were on HBase 94. To upgrade to latest version, we need to figure out a way to live upgrade while keeping Pinterest site live. Recently, we successfully upgrade 94 HBase cluster to 1.2 with no downtime. We made change to both Asynchbase and HBase server side. We will talk about what we did and how we did it. We will also talk about the finding in config and performance tuning we did to achieve low latency.

2. Tian-Ying Chang
Storage & Caching, Engineering @ Pinterest
Removable Singularity
AStoryof HBaseUpgradeatPinterest

3. 1
2
3
4
5
Agenda Usage of HBase in Pinterest
Upgrading Situation and Challenges
Migration Steps
Performance Tuning
Final Notes

4. HBase @ Pinterest
§Early applications: homefeed, search & discovery
§UserMetaStore: a generic store layer for all applications using user
KV data
§Zen: a graph service layer
• Many applications can be modeled as graph
• Usage of HBase flourished after Zen release
§Other misc. use cases, e.g., analytics, OpenTSDB

5. 40+ HBase clusters on 0.94

6. Need Upgrading
§HBase 0.94 is not supported by community anymore
§Newer version has better reliability, availability and
performance
§Easier to contribute back to community

7. Singularity of HBase 0.96
§RPC protocol changes
§Data format changes
§HDFS folder structure changes
§API changes
§Generally considered “impossible” to live upgrade without
downtime
http://blog.cloudera.com/blog/2012/06/the-singularity-hbase-compatibility-and-extensibility/

8. The Dilemma
§Singularity: cannot live upgrade from HBase 0.94 to later
version
• Need downtime
§Pinterest hosts critical online real time services on HBase
• Cannot afford downtime
§Stuck?

9. Fast Forward
§Successfully upgraded production clusters last
year
• Chose one of the most loaded clusters as pilot
• No application redeploy needed on the day of switching
to 1.2 cluster
• Live switch with no interrupt to Pinterest site
§Big performance improvement

10. P99LatencyofDifferentAPIs
Pointof LiveSwitch

11. How did we do it?

12. ZK
Client
read/write
HBase 0.94

13. ZK
Client
read/write
HBase 0.94 HBase 0.94
native
replication

14. ZK
Client
read/write
HBase 0.94 HBase 0.94
native
replication

15. ZK
Client
read/write
HBase 0.94

16. ZK
Client
read/write
HBase 0.94 HBase 0.94
1. Build empty cluster

17. ZK
Client
read/write
HBase 0.94 HBase 0.94
native
replication
1. Build empty cluster
2. Setup replication

18. ZK
Client
read/write
HBase 0.94 HBase 0.94
native
replication
1. Build empty cluster
2. Setup replication
3. Export snapshot

19. ZK
Client
read/write
HBase 0.94 HBase 0.94
native
replication
1. Build empty cluster
2. Setup replication
3. Export snapshot
4. Recover table from snapshot

20. ZK
Client
read/write
HBase 0.94 HBase 0.94
native
replication
1. Build empty cluster
2. Setup replication
3. Export snapshot
4. Recover table from snapshot
5. Replication drain

21. ZK
Client
read/write
HBase 0.94 HBase 0.94
native
replication

22. ZK
Client
read/write
HBase 0.94 HBase 1.2replication

23. ZK
Client
read/write
HBase 0.94 HBase 1.2replication

24. ZK
Client
read/write
HBase 0.94HBase 0.94

25. ZK
Client
read/write
HBase 0.94 HBase 1.2
1. Build empty cluster
HBase 0.94

26. ZK
Client
read/write
HBase 0.94 HBase 1.2
non-native
replication
1. Build empty cluster
2. Setup replication
HBase 0.94

27. ZK
Client
read/write
HBase 0.94 HBase 1.2
non-native
replication
1. Build empty cluster
2. Setup replication
3. Export snapshot
HBase 0.94

28. ZK
Client
read/write
HBase 0.94 HBase 1.2
non-native
replication
1. Build empty cluster
2. Setup replication
3. Export snapshot
4. Recover 1.2 table from 0.94 snapshot
HBase 0.94

29. ZK
Client
read/write
HBase 0.94 HBase 1.2
non-native
replication
1. Build empty cluster
2. Setup replication
3. Export snapshot
4. Recover table from snapshot
5. Replication drain
HBase 0.94

30. ZK
Client
read/write
HBase 0.94 HBase 1.2
non-native
replicationHBase 0.94

31. Major Problems to Solve
Client able to talk to both 0.94 and 1.2 automatically
Data can be replicated between HBase 0.94 and 1.2 bi-
directional

32. AsyncHBase Client
§Chose AsyncHBase due to better throughput and latency
• Stock AsyncHBase 1.7 can talk to both 0.94 and later version by
detecting the HBase version and use different protocol
§But cannot directly use stock AsyncHBase 1.7
• We made many private improvements internally
• Need to make those private features work with 1.2 cluster

33. AsyncHBase Client Improvements
§ BatchGet (open sourced in tsdb 2.4)
§ SmallScan
§ Ping feature to handle AWS network issue
§ Pluggable metric framework
§ Metrics broken down by RPC/region/RS
• Useful for debugging issues with better slice and dice
§ Rate limiting feature
• Automatically throttle/blacklist requests based on, e.g., latency
• Easier and better place to do throttling than at HBase RS side
§ In progress to open source

34. Live Data Migration
§Export snapshots from 0.94, recover tables in 1.2
• Relatively easy since we were already doing it between 0.94 and 0.94
• Modifying our existing DR/backup tool to work between 0.94 and
1.2
§Bidirectional live replication between 0.94 and 1.2
• Breaking changes in RPC protocol means native replication does not
work
• Using thrift replication to overcome the issue

35. Thrift Replication
§Patch from Flurry HBASE-12814
§Fixed a bug in the 0.98/1.2 version
• Threading bug exposed during prod data testing with high write QPS
• Fixed by implementing thrift client connection pool for each replication sink
• Fix also made the replication more performant
§Bidirectional is needed for potential rollback
§Verification!!
• Chckr: tool for checking data replication consistency between 0.94 and 1.2 cluster
• Used a configurable timestamp parameter to eliminate false positive caused by
replication delay

36. Upgrade Steps (Recap)
§Build new 1.2 empty cluster
§Set up master/master thrift replication between 0.94 and 1.2
§Export snapshot from 0.94 into 1.2 cluster
§Recover table in 1.2 cluster
§Replication draining
§Monitor health metrics
§Switch client to use 1.2 cluster

37. Performance
§Use production dark read/write traffic to verify performance
§Measured round trip latency from AsyncHBase layer
• Cannot do server latency compare since 1.2 has p999 server side
latency, while 0.94 does not
• Use metric breakdown by RPS/region/RS with Ostrich
implementation to compare performance

38. Get
BatchGet
Put
CompAndSet
Delete

39. Read Performance
§Default config has worse p99 latency **
• Bucket cache hurts p99 latency due to bad GC
§Short circuit read helps latency
§Use CMS instead of G1GC
§Native checksum helps latency
**The read path off-heap feature from 2.0 should help a lot. HBASE-17138

40. Write Performance
§Use write heavy load user case to expose perf issues
§Metrics shows much higher wal sync ops than 0.94
§Disruptor based wal sync implementation caused too much wal
sync operation
§hbase.regionserver.hlog.syncer.count default is 5, changed to 1

41. Thanks!
Community helps from Michael Stack and Rahul Gidwani

42. © Copyright, All Rights Reserved, Pinterest Inc. 2017
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