Hi Robert It could be because there are no free slots available in your cluster during job submission time to launch those tasks. Some other tasks may have already occupied the map/reduce slots.
When you experience this random issue please verify whether there are free task slots available. Regards Bejoy KS Sent from handheld, please excuse typos. -----Original Message----- From: Robert Dyer <psyb...@gmail.com> Date: Thu, 12 Jul 2012 23:03:02 To: <mapreduce-user@hadoop.apache.org> Reply-To: mapreduce-user@hadoop.apache.org Subject: Jobs randomly not starting I'm using Hadoop 1.0.3 on a small cluster (1 namenode, 1 jobtracker, 2 compute nodes). My input size is a sequence file of around 280mb. Generally, my jobs run just fine and all finish in 2-5 minutes. However, quite randomly the jobs refuse to run. They submit and appear when running 'hadoop job -list' but don't appear on the jobtracker's webpage. If I manually type in the job ID on the webpage I can see it is trying to run the setup task - the map tasks haven't even started. I've left them to run and even after several minutes it is still in this state. When I spot this, I kill the job and resubmit it and generally it works. A couple of times I have seen similar problems with reduce tasks that get stuck while 'initializing'. Any ideas?
