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Explorer
Posts: 25
Registered: ‎07-21-2015

No daemons are running after formatting the namenode

After I format Namenode in singlenode cluster, I am not able to see any any java process or hadoop daemnos running in my cluster..I have restarted the cluster many times. But it didn't work.

 

 

Please help  me ASAP

Cloudera Employee
Posts: 435
Registered: ‎07-12-2013

Re: No daemons are running after formatting the namenode

Reformatting the NameNode deletes all the metadata - it won't automatically
delete all the data. When the DataNode tries to connect, it recognizes that
the "ClusterId" has changed and it acts as though it's connected to the
wrong NameNode. If this is the case your DataNode logs
(/var/lib/hadoop-hdfs/hadoop-hdfs-datanode-quickstart.cloudera.log) will
contain some error messages about "incompatible clusterIDs". To have your
DataNodes use the newly formatted NameNode, clear out the data directory
(this of course deletes all the underlying blocks of data, so if you wanted
to keep it I hope you backed up the data before formatting the NameNode).
On the QuickStart VM you can clear out the data directory as follows:

sudo rm -r /var/lib/hadoop-hdfs/cache/hdfs/dfs/data/current

Other services that run on top of HDFS may require certain directory
structures to be created. You can create all of these on the new HDFS
cluster by running 'sudo /usr/lib/hadoop/libexec/init-hdfs.sh'.

Explorer
Posts: 25
Registered: ‎07-21-2015

Re: No daemons are running after formatting the namenode

I am not able to see 'init-hdfs.sh' inside /usr/lib/hadoop/libexec . Iam running hadoop-2.3 version in ubuntu VM. Please Help me
Cloudera Employee
Posts: 435
Registered: ‎07-12-2013

Re: No daemons are running after formatting the namenode

How did you install Hadoop? If you're using any of the versions of CDH that were based on Hadoop 2.3, that file should exist. But if you used Cloudera Manager it may have installed using parcels, instead of Linux packages, in which case that file should be in /opt/cloudera/parcels/CDH/lib/hadoop/libexec/init-hdfs.sh. If you downloaded Hadoop direct from hadoop.apache.org or some other source, then here's a copy of the script for the last version of CDH that was based on Hadoop 2.3: https://github.com/cloudera/cdh-package/blob/cdh5-0.6.0_5.1.0/bigtop-packages/src/common/hadoop/init... It should set up everything the way YARN expects, but you might hit some minor differences between distributions.

Explorer
Posts: 25
Registered: ‎07-21-2015

Re: No daemons are running after formatting the namenode

In installed direclty from apache hadoop site hadoopp-2.3 is the version. I can see only these files inside /usr/lib/hadoop/hadoop-2.3.0/libexec

/usr/lib/hadoop/hadoop-2.3.0/libexec$ ls
hadoop-config.cmd hdfs-config.sh mapred-config.sh
hadoop-config.sh httpfs-config.sh yarn-config.cmd
hdfs-config.cmd mapred-config.cmd yarn-config.sh



Cloudera Employee
Posts: 435
Registered: ‎07-12-2013

Re: No daemons are running after formatting the namenode

Official releases of Apache Hadoop do not include that script. It's
included in CDH and probably any other distribution based on Apache Bigtop.
You can try the copy that I linked you to on Github, but remember that
Cloudera does not officially support upstream releases - you may find
little differences when using the official Apache releases that we don't
test for.

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Explorer
Posts: 25
Registered: ‎07-21-2015

Re: No daemons are running after formatting the namenode

Now I am getting
jps
6037 ResourceManager
8467 Jps
5893 SecondaryNameNode

None other daemons are running. Is there any other way that i can get back my cluster
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