No the datanodes are running on different sets of machines. The configuration
looks like this:
The problem is that datanodes in clusterA are trying to connect to namenodes in
clusterB (and this seems random.. like it trying to randomly select from the 4
namenodes)
property
namedfs.nameservices/name
valueclusterA,clusterB/value
description
Comma-separated list of nameservices.
/description
finaltrue/final
/property
property
namedfs.nameservice.id/name
valueclusterA/value
description
The ID of this nameservice. If the nameservice ID is not
configured or more than one nameservice is configured for
dfs.nameservices it is determined automatically by
matching the local node's address with the configured address.
/description
finaltrue/final
/property
property
namedfs.ha.namenodes.clusterA/name
valueclusterAnn1,clusterAnn2/value
description
The prefix for a given nameservice, contains a comma-separated
list of namenodes for a given nameservice (eg EXAMPLENAMESERVICE).
/description
finaltrue/final
/property
property
namedfs.namenode.rpc-address.clusterA.clusterAnn1/name
valueclusterAnn1:8000/value
description
Set the full address and IPC port of the NameNode process
/description
finaltrue/final
/property
property
namedfs.namenode.rpc-address.clusterA.clusterAnn2/name
valueclusterAnn1:8000/value
description
Set the full address and IPC port of the NameNode process
/description
finaltrue/final
/property
property
namedfs.ha.namenodes.clusterB/name
valueclusterBnn1,clusterBnn2/value
description
The prefix for a given nameservice, contains a comma-separated
list of namenodes for a given nameservice (eg EXAMPLENAMESERVICE).
/description
finaltrue/final
/property
property
namedfs.namenode.rpc-address.clusterB.clusterBnn1/name
valueclusterBnn1:8000/value
description
Set the full address and IPC port of the NameNode process
/description
finaltrue/final
/property
property
namedfs.namenode.rpc-address.clusterB.clusterBnn2/name
valueclusterBnn2:8000/value
description
Set the full address and IPC port of the NameNode process
/description
finaltrue/final
/property
property
namedfs.client.failover.proxy.provider.clusterA/name
valueorg.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider/value
description
Configure the name of the Java class which the DFS Client will
use to determine which NameNode is the current Active,
and therefore which NameNode is currently serving client requests.
/description
finaltrue/final
/property
property
namedfs.client.failover.proxy.provider.clusterB/name
valueorg.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider/value
description
Configure the name of the Java class which the DFS Client will
use to determine which NameNode is the current Active,
and therefore which NameNode is currently serving client requests.
/description
finaltrue/final
/property
Regards,
Dhaval
From: Suresh Srinivas sur...@hortonworks.com
To: hdfs-u...@hadoop.apache.org user@hadoop.apache.org; Dhaval Shah
prince_mithi...@yahoo.co.in
Sent: Tuesday, 29 January 2013 6:03 PM
Subject: Re: Using distcp with Hadoop HA
Currently, as you have pointed out, client side configuration based failover is
used in HA setup. The configuration must define namenode addresses for the
nameservices of both the clusters. Are the datanodes belonging to the two
clusters running on the same set of nodes? Can you share the configuration you
are using, to diagnose the problem?
- I am trying to do a distcp from cluster A to cluster B. Since no operations
are supported on the standby namenode, I need to specify either the active
namenode while using distcp or use the failover proxy provider
(dfs.client.failover.proxy.provider.clusterA) where I can specify the two
namenodes for cluster B and the failover code inside HDFS will figure it out.
- If I use the failover proxy provider, some of my datanodes on cluster A would
connect to the namenode on cluster B and vice versa. I am assuming that is
because I have configured both nameservices in my hdfs-site.xml for distcp to
work.. I have configured dfs.nameservice.id to be the right one but the
datanodes do not seem to respect that.
What is the best way to use distcp with Hadoop HA configuration without having
the datanodes to connect to the remote namenode? Thanks
Regards,
Dhaval
--
http://hortonworks.com/download/
