Sparkling Water

Sparkling Water integrates H₂O's fast scalable machine learning engine with Spark. It provides:

• utilities to publish Spark data structures (RDDs, DataFrames) as H2O's frames and vice versa.
• DSL to use Spark data structures as input for H2O's algorithms
• basic building blocks to create ML applications utilizing Spark and H2O APIs
• Python interface enabling use of Sparkling Water directly from pyspark

Getting Started

Select right version

The Sparkling Water is developed in multiple parallel branches. Each branch corresponds to Spark major release (e.g., branch rel-1.5 provides implementation of Sparkling Water for Spark 1.5).

Please, switch to the right branch:

• For Spark 1.5 use branch rel-1.6
• For Spark 1.5 use branch rel-1.5
• For Spark 1.4 use branch rel-1.4
• For Spark 1.3 use branch rel-1.3

Note: The master branch includes the latest changes for the latest Spark version. They are back-ported into older Sparkling Water versions.

Requirements

• Linux/OS X/Windows
• Java 7+
• Spark 1.3+
  • SPARK_HOME shell variable must point to your local Spark installation

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Build

Download Spark installation and point environment variable SPARK_HOME to it. Then use the provided gradlew to build project:

./gradlew build

To avoid running tests, use the -x test -x integTest option.

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Download Binaries

• Sparkling Water - Latest version

Note: For each version of Spark there is a corresponding Sparkling Water version (i.e., for Spark 1.5 we provide Sparkling water and Maven artifacts with version 1.5.X)

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Run Sparkling shell

The Sparkling shell provides a regular Spark shell that supports creation of an H₂O cloud and execution of H₂O algorithms.

First, build a package containing Sparkling water:

./gradlew assemble

Configure the location of Spark cluster:

export SPARK_HOME="/path/to/spark/installation"
export MASTER="local-cluster[3,2,1024]"

In this case, local-cluster[3,2,1024] points to embedded cluster of 3 worker nodes, each with 2 cores and 1G of memory.

And run Sparkling Shell:

bin/sparkling-shell

Sparkling Shell accepts common Spark Shell arguments. For example, to increase memory allocated by each executor, use the spark.executor.memory parameter: bin/sparkling-shell --conf "spark.executor.memory=4g"

And initialize H2OContext

import org.apache.spark.h2o._
val hc = H2OContext.getOrCreate(sc)

H2OContext start H2O services on top of Spark cluster and provides primitives for transformations between H2O and Spark datastructures.

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Run examples

Build a package that can be submitted to Spark cluster:

./gradlew assemble

Set the configuration of the demo Spark cluster (for example, local-cluster[3,2,1024])

export SPARK_HOME="/path/to/spark/installation"
export MASTER="local-cluster[3,2,1024]"

In this example, the description local-cluster[3,2,1024] causes creation of a local cluster consisting of 3 workers.

And run the example:

bin/run-example.sh

For more details about the demo, please see the README.md file in the examples directory.

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Additional Examples

You can find more examples in the examples folder.

Running (Scala) Sparkling Water in IntelliJ IDEA

• In IDEA, install the Scala plugin for IDEA
• In a Terminal:

git clone https://github.com/h2oai/sparkling-water.git
cd sparkling-water
./gradlew idea
open sparkling-water.ipr

• In IDEA, open the file sparkling-water/core/src/main/scala/water/SparklingWaterDriver.scala
• [ Wait for IDEA indexing to complete so the Run and Debug choices are available ]
• In IDEA, Run or Debug SparklingWaterDriver (via right-click)

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PySparkling

Sparkling Water can be also used directly from pySpark

First, build a package:

./gradlew build -x check

Configure the location of Spark distribution and cluster:

export SPARK_HOME="/path/to/spark/installation"
export MASTER="local-cluster[3,2,1024]"

And run pySparkling shell:

bin/pysparkling

The pysparkling shell accepts common pyspark arguments.

And initialize H2OContext

import pysparkling
hc = H2OContext(sc).start()

To run pysparkling on top of Spark cluster, H2O Python package is required. You can install it via pip or point to it via PYTHONPATH shell variable: export PYTHONPATH=$PYTHONPATH:$H2O_HOME/h2o-py

To use Python notebook with pysparkling you need to specify IPYTHON_OPTS shell variable: IPYTHON_OPTS="notebook" bin/pysparkling

To use iPython with pysparkling you need to specify PYSPARK_PYTHON shell variable: PYSPARK_PYTHON="ipython" bin/pysparkling

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Sparkling Water as Spark Package

Sparkling Water is also published as a Spark package. You can use it directly from your Spark distribution.

For example, if you have Spark version 1.5 and would like to use Sparkling Water version 1.5.2 and launch example CraigslistJobTitlesStreamingApp, then you can use the following command:

$SPARK_HOME/bin/spark-submit --packages ai.h2o:sparkling-water-core_2.10:1.5.2,ai.h2o:sparkling-water-examples_2.10:1.5.2 --class org.apache.spark.examples.h2o.CraigslistJobTitlesStreamingApp /dev/null

The Spark option --packages points to published Sparkling Water packages in Maven repository.

The similar command works for spark-shell:

$SPARK_HOME/bin/spark-shell --packages ai.h2o:sparkling-water-core_2.10:1.5.2,ai.h2o:sparkling-water-examples_2.10:1.5.2 

The same command works for Python programs:

$SPARK_HOME/bin/spark-submit --packages ai.h2o:sparkling-water-core_2.10:1.5.2,ai.h2o:sparkling-water-examples_2.10:1.5.2 example.py

Note: When you are using Spark packages you do not need to download Sparkling Water distribution! Spark installation is sufficient!

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Docker Support

See docker/README.md to learn about Docker support.

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Contributing

Look at our list of JIRA tasks for new contributors or send your idea to [email protected].

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Issues

To report issues, please use our JIRA page at http://jira.h2o.ai/.

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Mailing list

Follow our H2O Stream.

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FAQ

• Where do I find the Spark logs?

Spark logs are located in the directory $SPARK_HOME/work/app-<AppName> (where <AppName> is the name of your application.

• Spark is very slow during initialization or H2O does not form a cluster. What should I do?

Configure the Spark variable SPARK_LOCAL_IP. For example:

export SPARK_LOCAL_IP='127.0.0.1'

• How do I increase the amount of memory assigned to the Spark executors in Sparkling Shell?

Sparkling Shell accepts common Spark Shell arguments. For example, to increase the amount of memory allocated by each executor, use the spark.executor.memory parameter: bin/sparkling-shell --conf "spark.executor.memory=4g"

• How do I change the base port H2O uses to find available ports?

  The H2O accepts spark.ext.h2o.port.base parameter via Spark configuration properties: bin/sparkling-shell --conf "spark.ext.h2o.port.base=13431". For a complete list of configuration options, refer to Devel Documentation.

• How do I use Sparkling Shell to launch a Scala test.script that I created?

Sparkling Shell accepts common Spark Shell arguments. To pass your script, please use -i option of Spark Shell: bin/sparkling-shell -i test.script

• How do I increase PermGen size for Spark driver?

Specify --conf spark.driver.extraJavaOptions="-XX:MaxPermSize=384m"

• How do I add Apache Spark classes to Python path?

Configure the Python path variable PYTHONPATH:

export PYTHONPATH=$SPARK_HOME/python:$SPARK_HOME/python/build:$PYTHONPATH
export PYTHONPATH=$SPARK_HOME/python/lib/py4j-0.8.2.1-src.zip:$PYTHONPATH

• Trying to import a class from the hex package in Sparkling Shell but getting weird error:

  error: missing arguments for method hex in object functions;
  follow this method with '_' if you want to treat it as a partially applied
  

  In this case you are probably using Spark 1.5 which is importing SQL functions into Spark Shell environment. Please use the following syntax to import a class from the hex package:

  import _root_.hex.tree.gbm.GBM
  

#Diagram of Sparkling Water on YARN

The following illustration depicts the topology of a Sparkling Water cluster of three nodes running on YARN: