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https://issues.apache.org/jira/browse/HBASE-8545?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13662133#comment-13662133
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ramkrishna.s.vasudevan commented on HBASE-8545:
-----------------------------------------------
Going thro the code once again, it is bit difficult to know whether the new
connection is to the same server but with different host or entirely a new
server.
If the below code
{code}
if (isDeadServer(serverName)) {
throw new RegionServerStoppedException(serverName + " is dead.");
}
{code}
works then things will be fine. Will see if anything can be done here if not we
can go with the current patch itself.
> Meta stuck in transition when it is assigned to a just restarted dead region
> sever
> -----------------------------------------------------------------------------------
>
> Key: HBASE-8545
> URL: https://issues.apache.org/jira/browse/HBASE-8545
> Project: HBase
> Issue Type: Bug
> Components: Region Assignment
> Reporter: Jimmy Xiang
> Assignee: Jimmy Xiang
> Attachments: trunk-8545.patch, trunk-8545_v2.patch
>
>
> Support the meta region server is down, and the SSH tries to re-assign it.
> This could happen:
> 1. AM plans to assign meta to a region server (R_old);
> 2. Now R_old is dead, the new region server (R_new) starts up on the same
> host, port, but gets a different start code;
> 3. AM sends the open region request to R_new and the Meta is opened on it;
> 4. AM gets ZK event, but it is from a different region server instance
> (R_new), not the expected one (R_old), so it sends a close region request to
> R_new;
> 5. Now, the meta is stuck in transition and won't be assigned.
> This won't happen to a user region since the SSH for R_old will find out the
> user region stuck in transition and re-assign it. For meta, it is a little
> different. AM checks if a dead region server carries the meta based on the
> ZK info, which is changed to the new region server R_new at step 3 by the
> open region handler.
> The fix I was thinking about is:
> 1. In checking if a region server carries a region, uses the region
> transition information if it exists (which is the source of truth, to
> master), if not, checks the ZK data as before;
> 2. In open region handler, when transition assign zk node from offline to
> opening, make sure the current region server is the expected one
> (ZK#transitionNode, existing code doesn't check the target server name).
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