Thank you. This explains why they appear to be running - they are queued. Mark
On Tue, Dec 29, 2009 at 11:30 AM, abhishek sharma <[email protected]>wrote: > Hi Mark, > > When you submit multiple jobs to the same cluster, these jobs are > queued up at the jobtracker, and executed in FIFO order. > > Based on my understanding of the Hadoop FIFO scheduler, the order in > which jobs get executed is determined by two things: (1) priority of > the job. All jobs have the NORMAL priority by default, (2) the start > time of the job. So in a scenario where all jobs have the same > priority, they will be executed in the order in which they arrive at > the cluster. > > If you submit multiple jobs, there is some initial processing that is > done before the job gets executed at the end of which a message > "Running job"+JOBID is printed. At this point, the job has been queued > up at the jobtracker awaiting execution. > > Hadoop also comes with other types of scheduler, for example, the Fair > Scheduler ( > http://hadoop.apache.org/common/docs/current/fair_scheduler.html). > > Hope this helps, > Abhishek > > On Tue, Dec 29, 2009 at 12:16 PM, Mark Kerzner <[email protected]> > wrote: > > Hi, > > > > what happens when I submit a few jobs on the cluster? To me, it seems > like > > they all are running - which I know can't be, because I only have 2 > slaves. > > Where do I read about this? > > > > I am using Cloudera with EC2. > > > > Thank you, > > Mark > > >
