HADOOP_HOME and hadoop streaming - hadoop

Hi I am trying to run hadoop on a server that has hadoop installed but I have no idea the directory where hadoop resides. The server was configure by the server admin.
In order to load hadoop I use the use command from the dotkit package.
There may be several solutions but wanted to know where the hadoop package was installed, how to set up the $HADOOP_HOME variable, and how to approp run a hadoop streaming job, such as $HADOOP_HOME/bin/hadoop jar $HADOOP_HOME/mapred/contrib/streaming/hadoop-streaming.jar, aka, http://wiki.apache.org/hadoop/HadoopStreaming.
Thanks! any help would be greatly appreciated!

If you're using a cloudera distribution then it's most probably in /usr/lib/hadoop, otherwise it could be anywhere (at the discretion of your system admin).
There are some tricks you can use to try and locate it:
locate hadoop-env.sh (assuming that locate has been installed and updatedb has been run recently)
If the machine you're running this on is running a hadoop service (such as data node, job tracker, task tracker, name node), then you can perform a process list and grep for the hadoop command: ps axww | grep hadoop
Failing the above two, look for the hadoop root directory in some common locations such as: /usr/lib, /usr/local, /opt
Failing all this, and assuming your current user has the permissions: find / -name hadoop-env.sh

If you're install with rpm then it's most probably in /etc/hadoop.

Why don't you try:
echo $HADOOP_HOME
Obiviously the above env variable has to be set before you could even issue hadoop executables from anywhere on the box.

Related

Spark installed but no command 'hdfs' or 'hadoop' found

I am a new pyspark user.
I just downloaded and installed a spark cluster ("spark-2.0.2-bin-hadoop2.7.tgz")
after installation I wanted to access the file system (upload local files to cluster). But when I tried to type hadoop or hdfs in command it will say "no command found".
Am I gonna install hadoop/HDFS (I thought it's built in the spark, I don't get)?
Thanks in advance.
You have to install hadoop first to access HDFS.
Follow this http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-single-node-cluster/
Choose the latest version of hadoop from the apache site.
Once you done with hadoop setup go to spark http://d3kbcqa49mib13.cloudfront.net/spark-2.0.2-bin-hadoop2.7.tgz download this, Extract files. Setup java_home and hadoop_home in spark-env.sh.
You don't have hdfs or hadoop on classpath so this is the reason why you are getting message: "no command found".
If you run \yourparh\hadoop-2.7.1\bin\hdfs dfs -ls / it should works and show root content.
But, You can add your hadoop/bin (hdfs, hadoop ...) commands to classpath with something like this:
export PATH $PATH:$HADOOP_HOME/bin
where HADOOP_HOME is your env. variable with path to hadoop installation folder (download and install is required)

Install spark on yarn cluster

I am looking for a guide regarding how to install spark on an existing virtual yarn cluster.
I have a yarn cluster consisting of two nodes, ran map-reduce job which worked perfect. Looked for results in log and everything is working fine.
Now I need to add the spark installation commands and configurations files in my vagrantfile. I can't find a good guide, could someone give me a good link ?
I used this guide for the yarn cluster
http://www.alexjf.net/blog/distributed-systems/hadoop-yarn-installation-definitive-guide/#single-node-installation
Thanks in advance!
I don't know about vagrant, but I have installed Spark on top of hadoop 2.6 (in the guide referred to as post-YARN) and I hope this helps.
Installing Spark on an existing hadoop is really easy, you just need to install it only on one machine. For that you have to download the one pre-built for your hadoop version from it's official website (I guess you can use the without hadoop version but you need to point it to the direction of hadoop binaries in your system). Then decompress it:
tar -xvf spark-2.0.0-bin-hadoop2.x.tgz -C /opt
Now you only need to set some environment variables. First in your ~/.bashrc (or ~/.zshrc) you can set SPARK_HOME and add it to your PATH if you want:
export SPARK_HOME=/opt/spark-2.0.0-bin-hadoop-2.x
export PATH=$PATH:$SPARK_HOME/bin
Also for this changes to take effect you can run:
source ~/.bashrc
Second you need to point Spark to your Hadoop configuartion directories. To do this set these two environmental variables in $SPARK_HOME/conf/spark-env.sh:
export HADOOP_CONF_DIR=[your-hadoop-conf-dir usually $HADOOP_PREFIX/etc/hadoop]
export YARN_CONF_DIR=[your-yarn-conf-dir usually the same as the last variable]
If this file doesn't exist, you can copy the contents of $SPARK_HOME/conf/spark-env.sh.template and start from there.
Now to start the shell in yarn mode you can run:
spark-shell --master yarn --deploy-mode client
(You can't run the shell in cluster deploy-mode)
----------- Update
I forgot to mention that you can also submit cluster jobs with this configuration like this (thanks #JulianCienfuegos):
spark-submit --master yarn --deploy-mode cluster project-spark.py
This way you can't see the output in the terminal, and the command exits as soon as the job is submitted (not completed).
You can also use --deploy-mode client to see the output right there in your terminal but just do this for testing, since the job gets canceled if the command is interrupted (e.g. you press Ctrl+C, or your session ends)

How to start Datanode? (Cannot find start-dfs.sh script)

We are setting up automated deployments on a headless system: so using the GUI is not an option here.
Where is start-dfs.sh script for hdfs in Hortonworks Data Platform? CDH / cloudera packages those files under the hadoop/sbin directory. However when we search for those scripts under HDP they are not found:
$ pwd
/usr/hdp/current
Which scripts exist in HDP ?
[stack#s1-639016 current]$ find -L . -name \*.sh
./hadoop-hdfs-client/sbin/refresh-namenodes.sh
./hadoop-hdfs-client/sbin/distribute-exclude.sh
./hadoop-hdfs-datanode/sbin/refresh-namenodes.sh
./hadoop-hdfs-datanode/sbin/distribute-exclude.sh
./hadoop-hdfs-nfs3/sbin/refresh-namenodes.sh
./hadoop-hdfs-nfs3/sbin/distribute-exclude.sh
./hadoop-hdfs-secondarynamenode/sbin/refresh-namenodes.sh
./hadoop-hdfs-secondarynamenode/sbin/distribute-exclude.sh
./hadoop-hdfs-namenode/sbin/refresh-namenodes.sh
./hadoop-hdfs-namenode/sbin/distribute-exclude.sh
./hadoop-hdfs-journalnode/sbin/refresh-namenodes.sh
./hadoop-hdfs-journalnode/sbin/distribute-exclude.sh
./hadoop-hdfs-portmap/sbin/refresh-namenodes.sh
./hadoop-hdfs-portmap/sbin/distribute-exclude.sh
./hadoop-client/sbin/hadoop-daemon.sh
./hadoop-client/sbin/slaves.sh
./hadoop-client/sbin/hadoop-daemons.sh
./hadoop-client/etc/hadoop/hadoop-env.sh
./hadoop-client/etc/hadoop/kms-env.sh
./hadoop-client/etc/hadoop/mapred-env.sh
./hadoop-client/conf/hadoop-env.sh
./hadoop-client/conf/kms-env.sh
./hadoop-client/conf/mapred-env.sh
./hadoop-client/libexec/kms-config.sh
./hadoop-client/libexec/init-hdfs.sh
./hadoop-client/libexec/hadoop-layout.sh
./hadoop-client/libexec/hadoop-config.sh
./hadoop-client/libexec/hdfs-config.sh
./zookeeper-client/conf/zookeeper-env.sh
./zookeeper-client/bin/zkCli.sh
./zookeeper-client/bin/zkCleanup.sh
./zookeeper-client/bin/zkServer-initialize.sh
./zookeeper-client/bin/zkEnv.sh
./zookeeper-client/bin/zkServer.sh
Notice: there are ZERO start/stop sh scripts..
In particular I am interested in the start-dfs.sh script that starts the namenode(s) , journalnode, and datanodes.
How to start DataNode
su - hdfs -c "/usr/lib/hadoop/bin/hadoop-daemon.sh --config /etc/hadoop/conf start datanode";
Github - Hortonworks Start Scripts
Update
Decided to hunt for it myself.
Spun up a single node with Ambari, installed HDP 2.2 (a), HDP 2.3 (b)
sudo find / -name \*.sh | grep start
Found
(a) /usr/hdp/2.2.8.0-3150/hadoop/src/hadoop-hdfs-project/hadoop-hdfs/src/main/bin/s‌​tart-dfs.sh
Weird that it doesn't exist in /usr/hdp/current, which should be symlinked.
(b) /hadoop/yarn/local/filecache/10/mapreduce.tar.gz/hadoop/sbin/start-dfs.sh
The recommended way to administer your hadoop cluster would be via the administrator panel. Since you are working on Hotronworks distribution, it makes more sense for you to use Ambari instead.

Spark: Run Spark shell from a different directory than where Spark is installed on slaves and master

I have a small cluster (4 machines) set up with 3 slaves and a master node, all installed to /home/spark/spark. (I.e, $SPARK_HOME is /home/spark/spark)
When I use the spark shell: /home/spark/spark/bin/pyspark --master spark://192.168.0.11:7077 everything works fine. However I'd like for my colleagues to be able to connect to the cluster from a local instance of spark on their machine installed in whatever directory they wish.
Currently if somebody has spark installed in say /home/user12/spark and run /home/user12/spark/bin/pyspark --master spark://192.168.0.11:7077 the spark shell will connect to the master without problems but fails with an error when I try to run code:
class java.io.IOException: Cannot run program
"/home/user12/bin/compute-classpath.sh"
(in directory "."): error=2, No such file or directory)
The problem here is that Spark is looking for the spark installation in /home/user12/spark/, where as I'd like to just tell spark to look in /home/spark/spark/ instead.
How do I do this?
You need to edit three files, spark-submit, spark-class and pyspark (all in the bin folder).
Find the line
export SPARK_HOME = [...]
Then change it to
SPARK_HOME = [...]
Finally make sure you set SPARK_HOME to the directory where spark is installed on the cluster.
This works for me.
Here you can find a detailed explanation.
http://apache-spark-user-list.1001560.n3.nabble.com/executor-failed-cannot-find-compute-classpath-sh-td859.html

Hadoop on Mesos fails with "Could not find or load main class org.apache.hadoop.mapred.MesosExecutor"

I have a Mesos cluster setup -- I have verified that the master can see the slaves -- but when I attempt to run a Hadoop job, all tasks wind up with a status of LOST. The same error is present in all the slave stderr logs:
Error: Could not find or load main class org.apache.hadoop.mapred.MesosExecutor
and that is the only line in the stderr logs.
Following the instructions on http://mesosphere.io/learn/run-hadoop-on-mesos/, I have put a modified Hadoop distribution on HDFS which each slave can access.
In the lib directory of the Hadoop distribution, I have added hadoop-mesos-0.0.4.jar and mesos-0.14.2.jar.
I have verified that each slave does in fact download this Hadoop distribution, and that hadoop-mesos-0.0.4.jar contains the class org.apache.hadoop.mapred.MesosExecutor, so I cannot figure out why the class cannot be found.
I am using Hadoop from CDH4.4.0 and mesos-0.15.0-rc4.
Does any one have any suggestions as to what might be the problem? I know I would always start with a CLASSPATH problem, but, in this case, the mesos-slave is downloading, unpacking, and attempting to run a Hadoop TaskTracker so I would imagine any CLASSPATH would be setup by the mesos-slave.
In the stdout of the slave logs, the environment is printed. There is a MESOS_HADOOP_HOME which is empty. Should this be set to something? If it is supposed to be set to the downloaded Hadoop distribution, I cannot set it in advance because the Hadoop distribution is downloaded to a new location every time.
In the event that is related (some permissions issue maybe), when attempting to browse slave logs via the master UI, I get the error Error browsing path: ....
The user running mesos-slave can browse to the correct directory when I do so manually.
I found the problem. bin/hadoop of the downloaded Hadoop distribution attempts to find its location by running which $0. However, that will find a current Hadoop installation if one exists (i.e. /usr/lib/hadoop), and will load the jars under that installation's lib directory instead of the downloaded one's lib directory.
I had to modify bin/hadoop of the downloaded distribution to find its own location with dirname $0 instead of which $0.

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