[ 
https://issues.apache.org/jira/browse/HBASE-10367?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16212231#comment-16212231
 ] 

Jerry He commented on HBASE-10367:
----------------------------------

Yes, the AC hooks are added.

For the recommission, the region list is optional. (I tried to use the 
Optional, but in the other JIRA we try to avoid using Optional as parameter.)  
It is up to the user/caller.  If it is not provided, then no region move.  
decommission and recommission need to pair up.
But a normal graceful stop sequence would be:
0. get regions for the region server.
1. decommission call with offloading of the regions.
2. Stop the region server. 
3. Start the region server (after patching, e.g.).
4. recommission call with the last list of regions.

The current graceful-stop script does similar steps, but with manual region 
mover.  We can get it to use the new APIs.

> RegionServer graceful stop / decommissioning
> --------------------------------------------
>
>                 Key: HBASE-10367
>                 URL: https://issues.apache.org/jira/browse/HBASE-10367
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Enis Soztutar
>            Assignee: Jerry He
>             Fix For: 3.0.0, 2.0.0-alpha-4
>
>         Attachments: HBASE-10367-master-2.patch, HBASE-10367-master.patch, 
> HBASE-10367-master.patch
>
>
> Right now, we have a weird way of node decommissioning / graceful stop, which 
> is a graceful_stop.sh bash script, and a region_mover ruby script, and some 
> draining server support which you have to manually write to a znode 
> (really!). Also draining servers is only partially supported in LB operations 
> (LB does take that into account for roundRobin assignment, but not for normal 
> balance) 
> See 
> http://hbase.apache.org/book/node.management.html and HBASE-3071
> I think we should support graceful stop as a first class citizen. Thinking 
> about it, it seems that the difference between regionserver stop and graceful 
> stop is that regionserver stop will close the regions, but the master will 
> only assign them after the znode is deleted. 
> In the new master design (or even before), if we allow RS to be able to close 
> regions on its own (without master initiating it), then graceful stop becomes 
> regular stop. The RS already closes the regions cleanly, and will reject new 
> region assignments, so that we don't need much of the balancer or draining 
> server trickery. 
> This ties into the new master/AM redesign (HBASE-5487), but still deserves 
> it's own jira. Let's use this to brainstorm on the design. 



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

Reply via email to