JAVA _Home is not set in Hadoop

Question

I am a beginner with hadoop and trying to install and run hadoop in my Ubuntu as a single node cluster. This is my JAVA_HOME in my hadoop_env.sh

# The java          


        

Answer 1

It not know space between Program and Files: "Program Files". So, I copy folder of jdk to C: or folder which not contains space in name of folder and assign: export JAVA_HOME=Name_Path_Copied. I see it run ok

Answer 2

I debugged the code and found out that even though JAVA_HOME is set in the environment, the value is lost as ssh connections to other hosts is made inside the code, and the JAVA_HOME variable that was showing well set in start-dfs.sh became unset in hadoop-env.sh.

The solution to this problem will be to set JAVA_HOME variable in hadoop-env.sh and it should work properly.

Answer 3

Above answers should work as long as you are using default conf directory $HADOOP_HOME/conf or $HADOOP_HOME/etc/hadoop. Here are a few things you should do if you're using a different conf folder.

1. Copy the hadoop-env.sh file from the default conf directory to your conf folder, say /home/abc/hadoopConf.

2. Replace the line

   #export JAVA_HOME=${JAVA_HOME}
   

   with the following:

   export JAVA_HOME=/usr/lib/jvm/java-8-oracle
   export HADOOP_CONF_DIR=/home/abc/hadoopConf
   

Change the values appropriately. If you have any other environment variables related to hadoop configured in your .bashrc or .profile or .bash_profile consider adding them next to the above lines.

Answer 4

I had the same error and solved it with Soil Jain's remark, but to make it even a bit more clear: the hadoop-env.sh uses an expression such as

export JAVA_HOME=${JAVA_HOME}

if you hard-code the path to your JVM installation it works

export JAVA_HOME=/usr/lib/jvm/java...

this resolution by environmental variable as is seems to fail. Hard-coding fixed the problem for me.

Answer 5

Are you loading hadoop_env.sh? you may be refering to hadoop-env.sh ( dash instead of underscore - that is under conf directory)

BTW, This is a very useful guide for quick installation :

http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-single-node-cluster/

Answer 6

First, you must set JAVA_HOME in your hadoop_env.sh . (your local JAVA_HOME in .bashrc would likely to be ignore somehow)

# The java implementation to use.
export JAVA_HOME=/usr/lib/jvm/default-java

Then, set HADOOP_CONF_DIR point to directory of your hadoop_env.sh . In ~/.bashrc, add the following line:

HADOOP_CONF_DIR="/usr/local/hadoop/etc/hadoop"
export HADOOP_CONF_DIR

Where /usr/local/hadoop/etc/hadoop is the directory contained hadoop_env.sh