[
https://issues.apache.org/jira/browse/HBASE-21444?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16678808#comment-16678808
]
Josh Elser commented on HBASE-21444:
------------------------------------
bq. Could you describe more about the case? Then we can decide if it is a
normal case HBase should cover or it is abnormal, should be fixed externally
like delete the meta node or by HBCK2.
I've talked to Ankit about this one once or twice now. The Ambari Metrics case
is definitely "odd-ball". Getting a super-old ZK root znode that doesn't jive
with meta or HDFS contents isn't something we'd want to "plan for" in HBase.
However, we have been noticing a trend of issues that cause meta to be
"orphaned" in an unassigned state. I think we can (greatly) improve the
user-experience by accepting that we will have more bugs like this ("for some
reason, meta is offline and we don't have an SCP which will get it assigned"),
and do some extra work to try to get it online ourselves. That's my take,
anyways :)
I need to read up on HBASE-21035 too. Thanks for the pointer!
> Recover meta in case of long ago dead region server appear in meta znode
> ------------------------------------------------------------------------
>
> Key: HBASE-21444
> URL: https://issues.apache.org/jira/browse/HBASE-21444
> Project: HBase
> Issue Type: Bug
> Affects Versions: 2.0.2
> Reporter: Ankit Singhal
> Assignee: Ankit Singhal
> Priority: Major
> Attachments: HBASE-21444.branch-2.0.001.patch,
> HBASE-21444.branch-2.0.002.patch
>
>
> Ambari metric server uses HBase as storage and currently have different
> znodes (/hbase-unsecure and /hbase-secure) to differentiate secure/unsecure
> deployment of HBase.
> As it also supports the rollback of the cluster from kerberised to
> non-kerberised (includes step of changing znode from /hbase-secure to
> /hbase-unsecure) , but with HBase 2.0 , meta-region-server znode from old
> zookeeper znodes will have regionserver which was long ago gone and there
> will be no procedure to transition it, resulting it to get stuck for lifetime.
> One option is to clear the znodes before rollingback but as it used to work
> with prior releases due to RecoverMetaProcedure, the ask is if we can fix
> meta assignment in case the wrong state is available in znode.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
