I want to understand how spark takes care of data localisation in cluster mode when run on YARN.
1.Driver program asks ResourceManager for executors. Does it tell yarn's RM to check HDFS blocks of input data and then allocate executors to it. And executors remain fixed throughout application or driver program asks for new executors when it submits another job in same application , since in spark new job is created for each action . If executors are fixed then for second job achieving data localisation is impossible? 2.When executors are done with their processing, does they are marked as free in ResourceManager's resoruce queue and executors directly tell this to Rm instead of via driver's ? Thanks Shushant
