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MapReduce >> mail # user >> About connection to NameNode in NameNode-HA


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Shinichi Yamashita 2012-11-01, 15:44
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Re: About connection to NameNode in NameNode-HA
Hi Yamashita,

Yes, the order in which the nodes are tried is indeed the order in which
your nodes are listed in the configuration.

We currently do write StandybException into the standby's logs, but I think
it's a good idea for an improvement to remove that, since it is an
"expected exception" and could cause too much log spew. Want to submit a
patch?

-Todd

On Thu, Nov 1, 2012 at 8:44 AM, Shinichi Yamashita <[EMAIL PROTECTED]>wrote:

> Hi,
>
> I write hdfs-site.xml of all nodes as follows in NameNode-HA.
>
> ----------
> ... snip  ...
>   <property>
>     <name>dfs.namenode.rpc-address.ns.nn1</name>
>     <value>nn1:8020</value>
>   </property>
>  <property>
>     <name>dfs.namenode.rpc-address.ns.nn2</name>
>     <value>nn2:8020</value>
>  </property>
>  <property>
>     <name>dfs.client.failover.proxy.provider.nn</name>
>
> <value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>
>  </property>
> ... snip ...
> ----------
> (nn : nameserviceID, nn1: NameNode1, nn2: NameNode2)
>
> Is the order of connection from DFSClient to NameNode always "(1) nn1"
> and "(2) nn2" ?
> And will "StandbyException" messages be written in the log of nn1 If
> the state of nn1 is standby?
>
> Regards,
> Shinichi
>

--
Todd Lipcon
Software Engineer, Cloudera
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Shinichi Yamashita 2012-11-04, 12:24