Using the job tracker node
DataStax Enterprise schedules a series of tasks on the analytics nodes for each MapReduce job that is submitted to the job tracker.
For each MapReduce job submitted to the job tracker, DataStax Enterprise schedules a series of tasks on the analytics nodes. One task tracker service per node handles the map and reduce tasks scheduled for that node. Within a data center, the job tracker monitors the execution and status of distributed tasks that comprise a MapReduce job.
You can use multiple job tracker nodes in a cluster, one per data center. In deployments having multiple data centers far away from each other, using multiple job trackers and multiple file systems can improve performance by taking advantage of data locality on each cluster.
Tasks related to the job tracker are: