How to create a chain of Hadoop job without using OOzie

Question

I want to create a chain of three Hadoop jobs, where the output of one job is fed as the input to the second job and so on. I would like to do this without using Oozie.

I have written the following code to acheive it :-

public class TfIdf {
    public static void main(String args[]) throws IOException, InterruptedException, ClassNotFoundException
    {
        TfIdf tfIdf = new TfIdf();
        tfIdf.runWordCount();
        tfIdf.runDocWordCount();
        tfIdf.TFIDFComputation();
    }

    public void runWordCount() throws IOException, InterruptedException, ClassNotFoundException
    {
        Job job = new Job();


        job.setJarByClass(TfIdf.class);
        job.setJobName("Word Count calculation");

        job.setMapperClass(WordFrequencyMapper.class);
        job.setReducerClass(WordFrequencyReducer.class);

        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(IntWritable.class);

        FileInputFormat.setInputPaths(job, new Path("input"));
        FileOutputFormat.setOutputPath(job, new Path("ouput"));

        job.waitForCompletion(true);
    }

    public void runDocWordCount() throws IOException, InterruptedException, ClassNotFoundException
    {
        Job job = new Job();

        job.setJarByClass(TfIdf.class);
        job.setJobName("Word Doc count calculation");

        job.setMapperClass(WordCountDocMapper.class);
        job.setReducerClass(WordCountDocReducer.class);

        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);

        FileInputFormat.setInputPaths(job, new Path("output"));
        FileOutputFormat.setOutputPath(job, new Path("ouput_job2"));

        job.waitForCompletion(true);
    }

    public void TFIDFComputation() throws IOException, InterruptedException, ClassNotFoundException
    {
        Job job = new Job();

        job.setJarByClass(TfIdf.class);
        job.setJobName("TFIDF calculation");

        job.setMapperClass(TFIDFMapper.class);
        job.setReducerClass(TFIDFReducer.class);

        job.setOutputKeyClass(Text.class);
        job.setOutputValueClass(Text.class);

        FileInputFormat.setInputPaths(job, new Path("output_job2"));
        FileOutputFormat.setOutputPath(job, new Path("ouput_job3"));

        job.waitForCompletion(true);
    }
}

However I get the error:

Input path does not exist: hdfs://localhost.localdomain:8020/user/cloudera/output

Could anyone help me out with this?

Answer 1

This answer is coming a little late, but... It's just a simple typo in your dir names. You've written your 1st job's output to dir "ouput", and your 2nd job is looking for it in "output".