Deep Learning on Apache Spark - Deeplearning4j: Open-source, Distributed Deep Learning for the JVM

Spark has a number of configuration options for how it controls execution. One important component of this is the settings around locality. Locality, simply put, refers to where data is relative to where data can be processed. Suppose an executor is free, but data would have to be copied across the network, in order to process it. Spark must decide whether it should execute that network transfer, or if instead it should wait for an executor that has local access to the data to become free.