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From shashwat shriparv <dwivedishash...@gmail.com>
Subject Re: High Availability - second namenode (master2) issue: Incompatible namespaceIDs
Date Fri, 16 Nov 2012 07:53:28 GMT
It seems u have formatted the namenode twice. In this case the namespace id
is not replicated to the datanodes.

Stop all the hadoop daemons and then try the following :

1. vi $PATH_TO_HADOOP_DATASTORE/dfs/name/current/VERSION and copy the
namespaceID value.
2.Now open a terminal on every machine having a datanode and do the
following:
vi $PATH_TO_HADOOP_DATASTORE/dfs/data/current/VERSION
Delete the entry corresponding to namespaceID and paste the value copied in
Step 1.
Save and exit.

Restart the hadoop daemons without formatting the namenode.



∞
Shashwat Shriparv




On Fri, Nov 16, 2012 at 1:22 PM, shashwat shriparv <
dwivedishashwat@gmail.com> wrote:

> Delete the VERSION for the datanode before format.
>
>
>
> ∞
> Shashwat Shriparv
>
>
>
>
> On Fri, Nov 16, 2012 at 1:15 PM, hadoop hive <hadoophive@gmail.com> wrote:
>
>> Seems like you havn't format your cluster (if its 1st time made).
>>
>> On Fri, Nov 16, 2012 at 9:58 AM, ac@hsk.hk <ac@hsk.hk> wrote:
>>
>>> Hi,
>>>
>>> Please help!
>>>
>>> I have installed a Hadoop Cluster with a single master (master1) and
>>> have HBase running on the HDFS.  Now I am setting up the second master
>>>  (master2) in order to form HA.  When I used JPS to check the cluster, I
>>> found :
>>>
>>> 2782 Jps
>>> 2126 NameNode
>>> 2720 SecondaryNameNode
>>> i.e. The datanode on this server could not be started
>>>
>>> In the log file, found:
>>> 2012-11-16 10:28:44,851 ERROR
>>> org.apache.hadoop.hdfs.server.datanode.DataNode: java.io.IOException:
>>> Incompatible namespaceIDs in /app/hadoop/tmp/dfs/data: namenode namespaceID
>>> = 1356148070; datanode namespaceID = 1151604993
>>>
>>>
>>>
>>> One of the possible solutions to fix this issue is to:  stop the
>>> cluster, reformat the NameNode, restart the cluster.
>>> QUESTION: As I already have HBASE running on the cluster, if I reformat
>>> the NameNode, do I need to reinstall the entire HBASE? I don't mind to have
>>> all data lost as I don't have many data in HBASE and HDFS, however I don't
>>> want to re-install HBASE again.
>>>
>>>
>>> On the other hand, I have tried another solution: stop the DataNode,
>>> edit the namespaceID in current/VERSION (i.e. set namespaceID=1151604993),
>>> restart the datanode, it doesn't work:
>>> Warning: $HADOOP_HOME is deprecated.
>>> starting master2, logging to
>>> /usr/local/hadoop-1.0.4/libexec/../logs/hadoop-hduser-master2-master2.out
>>> Exception in thread "main" java.lang.NoClassDefFoundError: master2
>>> Caused by: java.lang.ClassNotFoundException: master2
>>> at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
>>> at java.security.AccessController.doPrivileged(Native Method)
>>>  at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
>>>  at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
>>> Could not find the main class: master2.  Program will exit.
>>> QUESTION: Any other solutions?
>>>
>>>
>>>
>>> Thanks
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>

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