Dear Wiki user, You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.
The "JobTracker" page has been changed by SteveLoughran. The comment on this change is: rephrase for better linking, crank back the SPOF claims on the JT. http://wiki.apache.org/hadoop/JobTracker?action=diff&rev1=2&rev2=3 -------------------------------------------------- 1. The TaskTracker nodes are monitored. If they do not submit heartbeat signals often enough, they are deemed to have failed and the work is scheduled on a different TaskTracker. - 1. The TaskTrackers notify the JobTracker when a task fails. The JobTracker decides what to do then: it may resubmit the job elsewhere, it may mark that specific record as something to avoid, and it may may even blacklist the TaskTracker as unreliable. + 1. A TaskTracker will notify the JobTracker when a task fails. The JobTracker decides what to do then: it may resubmit the job elsewhere, it may mark that specific record as something to avoid, and it may may even blacklist the TaskTracker as unreliable. 1. When the work is completed, the JobTracker updates its status. 1. Client applications can poll the JobTracker for information. - The JobTracker is a point of failure for the Map/Reduce infrastructure. If it goes down, all running jobs are lost. The fileystem remains live. + The JobTracker is a point of failure for the Hadoop MapReduce service. If it goes down, all running jobs are halted.
