[HBASE-16060] 1.x clients cannot access table state talking to 2.0 cluster - ASF JIRA

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Details

Type: Bug
Status: Closed
Priority: Blocker
Resolution: Fixed
Affects Version/s: None
Fix Version/s: 2.0.0-beta-2, 2.0.0
Component/s: None
Labels:
None

Release Note:

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By default, we mirror table state to zookeeper so hbase-1.x clients will work against an hbase-2 cluster (With this patch, hbase-1.x clients can do most Admin functions including table create; hbase-1.x clients can do all Table/DML against hbase-2 cluster).

Flag to disable mirroring is hbase.mirror.table.state.to.zookeeper; set it to false in Configuration.

Related, Master on startup will look to see if there are table state znodes left over by an hbase-1 instance. If any found, it will migrate the table state to hbase-2 setting the state into the hbase:meta table where table state is now kept. We will do this check on every Master start. Notion is that this will be overall beneficial with low impediment. To disable the migration check, set hbase.migrate.table.state.from.zookeeper to false.

Show
By default, we mirror table state to zookeeper so hbase-1.x clients will work against an hbase-2 cluster (With this patch, hbase-1.x clients can do most Admin functions including table create; hbase-1.x clients can do all Table/DML against hbase-2 cluster). Flag to disable mirroring is hbase.mirror.table.state.to.zookeeper; set it to false in Configuration. Related, Master on startup will look to see if there are table state znodes left over by an hbase-1 instance. If any found, it will migrate the table state to hbase-2 setting the state into the hbase:meta table where table state is now kept. We will do this check on every Master start. Notion is that this will be overall beneficial with low impediment. To disable the migration check, set hbase.migrate.table.state.from.zookeeper to false.

Description

Since table state is migrated to meta instead of zk in 2.0, 1.x clients talking to 2.0 cluster cannot access the table state. This causes some weird behavior since from a client perspective, Admin.isTableEnabled() and Admin.isTableDisabled() both return false.

One option we can do is to add code in 1.x clients so that they can access the table state in meta if needed. Otherwise, we can mirror the table state in zk (while keeping meta as the source of truth) during 2.x lifecycle so that any 1.x client can still work correctly.