Chaining multiple MapReduce jobs in Hadoop

Question

Hi, I am using MapReduce and there are so many steps in it. I want the value of the last reduced step as that is what is needed. Can anyone suggest me a method to get rid of chaining multiple MapReduce Jobs in Hadoop? Please give an example (if possible) for cleanup of these P.s. Thank you in advance. Select the correct answer from above options questions and answers, questions pdf, question bank, questions and answers pdf, mcq on pdf, questions and solutions, mcq Test , Interview questions, Questions for Interview, MCQ (Multiple Choice Questions),Core Questions, Core Hadoop MCQ,core interview questions for experienced

Answer 1

There are multiple methods for the same, I’ll explain one of them here, you will be able to easily chain jobs together in this manner by writing multiple driver methods, one for each of them. First Call the first driver method, that uses JobClient.runJob() to run the job and wait for its completion. When the job has completed, then call next driver method, which will create a new JobConf object referring to different instances. Create the JobConf object "one" for the first job. Execute this job: JobClient.run(one). Then, create another JobConf object "two" for the next job. Execute this job: JobClient.run(two).