[HBASE-18640] Move mapreduce out of hbase-server into separate hbase-mapreduce module

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.0.0-alpha-3, 2.0.0

Release Note

- Moves all org.apache.hadoop.hbase.mapreduce.* (except LoadIncrementalHFiles) and org.apache.hadoop.hbase.mapred.* classes from hbase-server module to new hbase-mapreduce module.
- Also moves following tools from hbase-server module to hbase-mapreduce module: CompactionTool, ExportSnapshot, PerformanceEvaluation, LoadTestTool
- Very minor breakages in LoadTestTool(LimitedPrivate HBaseInterfaceAudience.TOOLS)

• Assignee: Apekshit Sharma
• Reporter: Apekshit Sharma
• Created: 21/Aug/17 01:33
• Updated: 17/Jun/22 17:21
• Resolved: 28/Aug/17 14:40

Description

(Couldn't find another dedicated jira, so creating new one).
Uploaded patch which is moving ~60 files to the new module. Few notes:

• The classes remaining in hbase-server are the ones which are intensively coupled with visibility labels/wal/filesystem/hfile. These can not be migrated to new module until corresponding subcomponents are untangled out of hbase-server into their own separate modules.
• Almost all mapreduce tests uses HBaseTestingUtil, so they can't be moved to hbase-mapreduce module. Given these dependency constraints, one way would be having a separate module for tests:
  hbase-mapreduce <---- hbase-server <------- hbase-mapreduce-tests
  Imo, this makes sense and looks fine.
  The only issue is - yetus' pre-commit. It won't run tests in hbase-mapreduce-tests module if something changed in just hbase-mapreduce. However, yetus' limitation shouldn't warrant against the idea.
  So i'd say that we should go that way, unless there are better suggestions.

Issue Links

• breaks: HBASE-18696 Fix the problems when introducing the new hbase-mapreduce module
• is duplicated by: HBASE-11843 MapReduce classes shouldn't be in hbase-server
• relates to: HBASE-14910 Create base hbase-mapred and hbase-io modules, move HTableInputFormat and HTableOutputFormat
• links to: Review Board (master)