How to resolve Invalid Hadoop Yarn Home error - hadoop

I'm trying to install Hadoop on CentOS7, following steps here - https://www.vultr.com/docs/how-to-install-hadoop-in-stand-alone-mode-on-centos-7 (Only difference Hadoop version is 3.2.1 instead of 2.7.3 in article)
I followed everything precisely until at step 4 when i type in "hadoop" in terminal it gives me an error - ERROR: Invalid HADOOP_YARN_HOME
Is there any setup related to Yarn thats needed? I read the Apache doc and other links on the web but they all mention only JAVA_HOME path is needed which I did set as per above link.
Any help appreciated.
Thanks!

Open ~/.bashrc
add
export HADOOP_HOME=path_to_your_hadoop_package
export HADOOP_YARN_HOME=$HADOOP_HOME

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I am trying to install kylo 0.8.4.
There is a step to install kylo specific components after installing Nifi using command,
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but getting follwing error.
Creating symlinks for NiFi version 1.4.0.jar compatible nars
ERROR: spark-submit not on path. Has spark been installed?
I have spark installed.
need help.
The script calls which spark-submit to check if Spark is available. If available, it uses spark-submit --version to determine the version of Spark that is installed.
The error indicates that spark-submit is not available on system path. Can you please execute which spark-submit on the command line and check the result? Please refer to the screenshot below for expected result on Kylo sandbox.
If spark-submit is not available on the system path, you can fix it by updating the PATHvariable in .bash_profile file by providing the location of your Spark installation.
As a next step, you can also verify the installed version of Spark by running spark-submit --version. Please refer to screenshot below for an example result.

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I am installing predictionIO from source code. I have downloaded and done the predictionIO installation successfully. I am now trying to install the dependencies (Spark, Elasticsearch, HBase) but I am running into errors for each of them. Below are the issues I am facing when I execute pio status:
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2 - It is also unable to find metadata files.
I have not changed any default settings. I'm using windows 8.1. On localhost, I have running IIS. On 127.0.0.1:8888 I run ipython notebook.
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Thanks
If you are on Windows, you can install with Vagrant.
http://docs.prediction.io/community/projects/#vagrant-installation-for-predictionio
I believe the discussion has moved to the google group.
https://groups.google.com/forum/#!searchin/predictionio-user/SAS/predictionio-user/ZamBr1ZaQ3o/fyNkXh3zsv0J
https://groups.google.com/forum/#!searchin/predictionio-user/SAS/predictionio-user/0awaASUR8lE/JkLtPeRrNt4J
This is the relevant thread.
https://groups.google.com/forum/#!searchin/predictionio-user/SAS/predictionio-user/0awaASUR8lE/JkLtPeRrNt4J
Moreover, PredictionIO docs had a few errors. Below are some of them and their corrected versions.
1 - Actual line: PATH=$PATH:/home/yourname/predictionio/bin; export PATH
Corrected Version PATH=$PATH:/home/yourname/PredictionIO/bin; export PATH
2 - Actual Line: $ pio eventserver
Corrected Version: $ pio eventserver --ip 0.0.0.0
3 - Actual Line pio template get PredictionIO/templates-scala-parallel-recommendation MyRecommendation
Corrected Version pio template get PredictionIO/template-scala-parallel-recommendation MyRecommendation

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cygwin warning:
MS-DOS style path detected: c:\pig/conf/pig.properties
Preferred POSIX equivalent is: /cygdrive/c/pig/conf/pig.properties
CYGWIN environment variable option "nodosfilewarning" turns off this warning.
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http://cygwin.com/cygwin-ug-net/using.html#using-pathnames
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To resolve the above error, I have rebuild pig for hadoop-2.2.0 as described in the below link and able to get rid of the exception.
http://javatute.com/javatute/faces/post/hadoop/2014/installing-pig-11-for-hadoop-2-on-ubuntu-12-lts.xhtml

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export HADOOP_OPTS="-Djava.security.krb5.realm=OX.AC.UK -Djava.security.krb5.kdc=kdc0.ox.ac.uk:kdc1.ox.ac.uk"
to your hadoop-env.sh file, which I have.
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java[1548:1703] Unable to load realm info from SCDynamicStore
amongst the outputs.
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export JAVA_HOME=`/usr/libexec/java_home -v 1.6`
(Note the grave quotes here.) This fixed the problem for me.
I had the same issue with java 7. works with java 6

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