Datanode process not running in Hadoop

Question

I set up and configured a multi-node Hadoop cluster using this tutorial.

When I type in the start-all.sh command, it shows all the processes initializing properly as

Answer 1

This is for newer version of Hadoop (I am running 2.4.0)

• In this case stop the cluster sbin/stop-all.sh
• Then go to /etc/hadoop for config files.

In the file: hdfs-site.xml Look out for directory paths corresponding to dfs.namenode.name.dir dfs.namenode.data.dir

• Delete both the directories recursively (rm -r).
• Now format the namenode via bin/hadoop namenode -format
• And finally sbin/start-all.sh

Hope this helps.

Answer 2

1. I configured hadoop.tmp.dir in conf/core-site.xml

2. I configured dfs.data.dir in conf/hdfs-site.xml

3. I configured dfs.name.dir in conf/hdfs-site.xml

4. Deleted everything under "/tmp/hadoop-/" directory

5. Changed file permissions from 777 to 755 for directory listed under dfs.data.dir

   And the data node started working.

Answer 3

Follow these steps and your datanode will start again.

1. Stop dfs.
2. Open hdfs-site.xml
3. Remove the data.dir and name.dir properties from hdfs-site.xml and -format namenode again.
4. Then remove the hadoopdata directory and add the data.dir and name.dir in hdfs-site.xml and again format namenode.
5. Then start dfs again.

Answer 4

Instead of deleting everything under the "hadoop tmp dir", you can set another one. For example, if your core-site.xml has this property:

<property>
  <name>hadoop.tmp.dir</name>
  <value>/home/hduser/data/tmp</value>
</property>

You can change this to:

<property>
  <name>hadoop.tmp.dir</name>
  <value>/home/hduser/data/tmp2</value>
</property>

and then scp core-site.xml to each node, and then "hadoop namenode -format", and then restart hadoop.

Answer 5

Error in datanode.log file

$ more /usr/local/hadoop/logs/hadoop-hduser-datanode-ubuntu.log

Shows:

java.io.IOException: Incompatible clusterIDs in /usr/local/hadoop_tmp/hdfs/datanode: namenode clusterID = CID-e4c3fed0-c2ce-4d8b-8bf3-c6388689eb82; datanode clusterID = CID-2fcfefc7-c931-4cda-8f89-1a67346a9b7c

Solution: Stop your cluster and issue the below command & then start your cluster again.

sudo rm -rf  /usr/local/hadoop_tmp/hdfs/datanode/*

Answer 6

Stop all the services - ./stop-all.sh Format all the hdfs tmp directory from all the master and slave. Don't forget to format from slave.

Format the namenode.(hadoop namenode -format)

Now start the services on namenode. ./bin/start-all.sh

This made a difference for me to start the datanode service.