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From: Ian Brooks <i.brooks@sensewhere.com>
To: user@hadoop.apache.org
Subject: Re: Upgrade to 2.4
Date: Fri, 30 May 2014 14:43:59 +0100
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Thanks,

Ill give it a try.

-Ian

On Friday 30 May 2014 19:43:00 Zesheng Wu wrote:
> Hi Ian,
> -rollingUpgrade is available since hadoop 2.4, so you can't use
> -rollingUpgrade to upgrade a 2.3 cluster to 2.4.
> Because HDFS 2.4 introduce protobuf formated fsimage, we must stop the
> whole cluster and then upgrade the cluster.
> I tried to upgrade a 2.0 HDFS cluster to 2.4 several days ago, following
> are some details, wish this can give some help to you:
> 
> 1. Put the active NN into safemode:  dfsadmin -safemode enter
> 2. Perform a saveNamespace operation: dfsadmin -saveNamespace
> 3. For each component you are using, back up configuration data, databases,
> and other important files
> 4. Shutdown hadoop serverice across your entire cluster
> 5. Check each host to make sure that there are no processes running
> hdfs/yarn
> 6. Back up your HDFS metadata
> 7. Upgrade and start the Journal Nodes and ZKFC
> 8. Make sure that all the journal nodes and zkfc have started normally
> 9. Execute this upgrade operation on active NN:  namenode -upgrade
> (Important)
> 10. Wait and make sure from ANN's log that upgrade is completed (from log)
> 11. Bootstrap standby NN: namenode -bootstrapStandby
> 12. Start standby NN: namenode start
> 13. Start each of the DNs: datanode start
> 14. Make sure that everything is running smoothly, this could take a matter
> of days, or even weeks
> 15. Finalize the hdfs metadata upgrade: dfsadmin -finalizeUpgrade
> 
> 
> 2014-05-30 17:54 GMT+08:00 Ian Brooks <i.brooks@sensewhere.com>:
> 
> > Hi,
> >
> > I though i'd give hadoop 2.4 a try as the improvements to rolling upgrades
> > would be useful to us. Unless i'm missing something, I can't see how to
> > upgrade from 2.3 to 2.4
> >
> > -rollingUpgrade doesnt work as the old namenode doesn't understand the
> > command and -upgrade is no longer available.
> >
> > I had a quick google and can't find any documentation on this upgrade,
> > does anyone know how its supposed to be done?
> >
> > -Ian
> >
> 
> 
> 
> 
-- 
-Ian Brooks
Senior server administrator - Sensewhere