06-19-2015 11:28 PM
In the definitive guide of Hadoop it is mentioned that:
"Sometimes the locality constraint cannot be met, in which case either no allocation is made or, optionally, the constraint can be loosened. For example, if a specific node was requested but it is not possible to start a container on it (because other containers are running on it), then YARN will try to start a container on a node in the same rack, or, if that’s not possible, on any node in the cluster."
I am not able to get this, because if my Application Manager needs a container on a particular node where my block resides and in case if the RM is not able to create a container on the particular node requested due to unavailability, it may create a container on another node according to the above sentence, how will it serve the purpose of localization?
06-20-2015 06:38 AM