title: Is it possible to specify which takstrackers to use in a MapReduce job?
body: <p>We have two types of jobs in our Hadoop cluster. One job uses MapReduce HBase scanning, the other one is just pure manipulation of raw files in HDFS. Within our HDFS cluster, part of the datanodes are also HBase regionservers, but others aren't. We would like to run the HBase scans only in the regionservers (to take advantage of the data locality), and run the other type of jobs in all the datanodes. Is this idea possible at all? Can we specify which tasktrackers to use in the MapReduce job configuration?</p>
  
  <p>Any help is appreciated. </p>