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https://issues.apache.org/jira/browse/HBASE-3909?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13037255#comment-13037255
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Andrew Purtell commented on HBASE-3909:
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Given that Hadoop does not require ZooKeeper, but we do anyway, I wonder if it
makes more sense to go our own route and host all of configuration in the
ZooKeeper namespace. It would therefore be possible to make one edit (committed
into ZK) and watches on all processes would automatically pull it.
The access controller on HBASE-3025 uses this approach for ACLs. Upon cold boot
they are loaded from META into znodes. Then all processes open watches on the
znode(s). Upon update, the znode is updated, firing the watchers, propagating
the change cluster wide.
For supporting dynamic configuration, the first process up could populate
znode(s) from Configuration; otherwise if the znodes exist configuration would
be read from there. Whenever the znode(s) are updated, the changes can be
applied to running state by the watcher.
How/if the updated configuration should be written back to the config xml files
on local disk may be a subject of debate.
> Add dynamic config
> ------------------
>
> Key: HBASE-3909
> URL: https://issues.apache.org/jira/browse/HBASE-3909
> Project: HBase
> Issue Type: Bug
> Reporter: stack
>
> I'm sure this issue exists already, at least as part of the discussion around
> making online schema edits possible, but no hard this having its own issue.
> Ted started a conversation on this topic up on dev and Todd suggested we
> lookd at how Hadoop did it over in HADOOP-7001
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