Book Image

Apache Spark for Data Science Cookbook

By : Padma Priya Chitturi
Book Image

Apache Spark for Data Science Cookbook

By: Padma Priya Chitturi

Overview of this book

Spark has emerged as the most promising big data analytics engine for data science professionals. The true power and value of Apache Spark lies in its ability to execute data science tasks with speed and accuracy. Spark’s selling point is that it combines ETL, batch analytics, real-time stream analysis, machine learning, graph processing, and visualizations. It lets you tackle the complexities that come with raw unstructured data sets with ease. This guide will get you comfortable and confident performing data science tasks with Spark. You will learn about implementations including distributed deep learning, numerical computing, and scalable machine learning. You will be shown effective solutions to problematic concepts in data science using Spark’s data science libraries such as MLLib, Pandas, NumPy, SciPy, and more. These simple and efficient recipes will show you how to implement algorithms and optimize your work.
Table of Contents (17 chapters)
Apache Spark for Data Science Cookbook
Credits
About the Author
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface

Submitting applications to a cluster


This recipe shows how to run an application on distributed clusters. An application is launched on a set of machines using an external service called a cluster manager. There is a wide variety of cluster managers such as Hadoop YARN, Apache Mesos, and Spark's own built-in standalone cluster manager. Spark provides a single tool for submitting jobs across all cluster managers, called spark-submit. Through various options, spark-submit can connect to different cluster managers and control how many resources your application gets.

Getting ready

To step through this recipe, you will need a running Spark cluster either in pseudo distributed mode or in one of the distributed modes, that is, standalone, YARN, or Mesos.

How to do it…

  1. Let's create a word count application:

            package org.apache.spark.programs 
            object WordCount{ 
            def main(args:Array[String]) { 
            val conf = new SparkConf 
            conf.setAppName("WordCount") 
            val sc = new SparkContext(conf) 
            val input =     
            sc.parallelize(Array("this,is,a,ball","it,is,a,cat","john,is,
            in,town,hall")) 
            val words = input.flatMap{record => record.split(",")} 
            val wordPairs = words.map(word => (word,1)) 
            val wordCounts = wordPairs.reduceByKey{(a,b) => a+b} 
            val result = wordCounts.collect 
            println("Displaying the WordCounts:") 
            result.foreach(println) 
    
  2. Submit the application to Spark's standalone cluster manager:

          spark-submit --class org.apache.spark.programs.WordCount --master 
          spark://master:7077 WordCount.jar 
    
    
  3. Submit the application to YARN:

          spark-submit --class org.apache.spark.programs.WordCount --master 
          yarn WordCount.jar
    
  4. Submit the application to Mesos:

          spark-submit --class org.apache.spark.programs.WordCount --master       
          mesos://mesos-master:5050 WordCount.jar
    

How it works…

When spark-submit is called with the --master flag as spark://master:7077 submits the application to Spark's standalone cluster. Invoking with the --master flag as yarn runs the application in the YARN cluster, whereas specifying the --master flag as mesos://mesos-master:5050 runs the application on Mesos cluster.

There's more…

Whenever spark-submit is invoked, it launches the driver program. This driver program contacts the cluster manager and requests resources to launch executors. Once the executors are launched by the cluster manager, the driver runs through the user application. It delegates the work to executors in the form of tasks. When the driver's main() method exits, it will terminate the executors and releases resources from the cluster manager. spark-submit provides various options as well to control specific details.

See also

For more information on submitting applications to a cluster and the various options provided by Spark-submit, please visit: http://spark.apache.org/docs/latest/submitting-applications.html. Also, for detailed information about the different cluster managers, please refer to the following:

Also, to learn in details about the different cluster managers, please refer: