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About connection to NameNode in NameNode-HA
Shinichi Yamashita 2012-11-01, 15:44
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
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Re: About connection to NameNode in NameNode-HA
Todd Lipcon 2012-11-01, 16:43
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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Re: About connection to NameNode in NameNode-HA
Shinichi Yamashita 2012-11-04, 12:24
Hi Todd,
Thank you for your answer. I will submit a patch whitch does not output log by some operation.
Regards, Shinichi 2012/11/2 Todd Lipcon <[EMAIL PROTECTED]>: > 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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