Is not your MapReduce AppMaster occupying one slot? Sent from my iPhone
> On 8 jul 2014, at 13:01, Tomasz Guziałek <[email protected]> wrote: > > Hello all, > > I am running a 4-nodes CDH5 cluster on Amazon EC2 . The instances used are > m1.large, so I have 4 cores (2 core x 2 unit) per node. My HBase table has 8 > regions, so I expected at least 8 (if not 16) mapper tasks to run > simultaneously. However, only 7 are running and 1 is waiting for an empty > slot. Why this surprising number came up? I have checked that the regions are > equally distributed on the region servers (2 per node). > > My properties in the job: > Configuration mapReduceConfiguration = HBaseConfiguration.create(); > mapReduceConfiguration.set("hbase.client.max.perregion.tasks", "4"); > mapReduceConfiguration.set("mapreduce.tasktracker.map.tasks.maximum", "16"); > > My properties in the CDH: > yarn.scheduler.minimum-allocation-vcores = 1 > yarn.scheduler.maximum-allocation-vcores = 4 > > Do I miss some property? Please share your experience. > > Best regards > Tomasz
