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Majid Azimi
Asked: 2011-10-16 10:04:24 +0800 CST

JAVA_HOME for Hadoop

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I want to configure hadoop to run in pseudo-distributed mode. My configuration files:

core-site.xml:

<configuration>
    <property>
        <name>fs.default.name</name>
        <value>hdfs://localhost/</value>
    </property>
</configuration>

hdfs-site.xml:

<configuration>
    <property>
        <name>dfs.replication</name>
        <value>1</value>
    </property>
</configuration>

mapred-site.xml:

<configuration>
    <property>
        <name>mapred.job.tracker</name>
        <value>localhost:8021</value>
    </property>
</configuration>

the hadoop version I'm using command hadoop version is:

Hadoop 0.20.203.0
Subversion http://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.20-security-203 -r 1099333
Compiled by oom on Wed May  4 07:57:50 PDT 2011

I have set the JAVA_HOME environmental variable to:(I'm using fedora 15)

/usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x86_64

the output of export $JAVA_HOME is:

/usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x86_64

But when I run start-dfs.sh it says:

localhost: Error: JAVA_HOME is not set.

The only thing that log files show is the above statement. Could anyone help?

hadoop

1 Answers

  1. Best Answer

    Check the hadoop-env.sh file in the Hadoop conf directory. Ensure the line exporting JAVA_HOME has been uncommented and set appropriately.

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