.. _Hadoop_Tutorial:
Running H\ :sub:`2`\ O on Hadoop
================================
The following tutorial will walk the user through the download or build of H\ :sub:`2`\ O and the parameters involved
in launching H\ :sub:`2`\ O from the command line.
**Step 1**
Either download the latest H\ :sub:`2`\ O release from our `download page `_ or download our
source code and build the code from git by running:
::
$ git clone https://github.com/0xdata/h2o.git
$ cd h2o
$ make
**Step 2**
Copy the build output or downloaded zip file to a Hadoop Node where the user will be running hadoop commands.
::
$ scp target/h2o-.zip
or
$ scp h2o-.zip
**Step 3**
Prepare job input on Hadoop Node by unzipping the build file and changing to the directory with the Hadoop and H\ :sub:`2`\ O's driver jar files.
::
$ unzip h2o-.zip
$ cd h2o-/hadoop
**Step 4**
To launch H\ :sub:`2`\ O nodes and form a cluster on the Hadoop cluster run:
::
$ hadoop jar water.hadoop.h2odriver [-jt ]
-libjars ../h2o.jar -mapperXmx 1g -nodes 1 -output hdfsOutputDirName
*Parameters*
h2o_driver_jar_file : For each major release of each distribution of hadoop, there is a driver jar file that the user will need to launch H\ :sub:`2`\ O with.
Currently available driver jar files in each build of H\ :sub:`2`\ O include h2odriver_cdh5.jar, h2odriver_hdp2.1.jar, and mapr2.1.3.jar.
jobtracker:port : The argument is optional and typically without it the jobtracker will be available at the default port of each distro.
mapperXmx : The mapper size or the amount of memory allocated to each node.
nodes : The number of nodes requested to form the cluster.
output : The name of the directory created for each mapper task which has to be unique to each instance of H\ :sub:`2`\ O since they cannot be overwritten.
**Step 5**
To monitor your job simply direct your web browser to your standard job tracker Web UI.
To access H\ :sub:`2`\ O's Web UI direct your web browser to one of the instances launched. If you are unsure where your port is launched
review the output from your command.
.. image:: hadoop_cmd_output.png
:width: 100 %