[HBASE-19172] [rolling upgrade] Migrate region state from zk to hbase:meta

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Duplicate
• Fix Version/s: 2.0.0-beta-2, 2.0.0
• Component/s: migration
• Assignee: Unassigned
• Reporter: Michael Stack
• Created: 03/Nov/17 22:12
• Updated: 24/Jun/22 18:05
• Resolved: 10/Feb/18 00:04

Description

HBASE-19165 is about starting a branch-2 over branch-1 dataset. The Master when it comes up, goes to read the 'state' of the region from hbase:meta because this is how region state is kept now by AMv2 only, there is no state in hbase:meta on a fresh start. In hbase1, region state was kept in master memory persisted to zk (rather than hbase:meta) while the region was in transition.

We need to add to master a self-migration facility. If a region has no state in hbase:meta, then look in zk to see if it RIT. If nothing in RIT, ask the pertinent regionserver if it has the region.