public class GiraphApplicationMaster
The YARN Application Master for Giraph is launched when the GiraphYarnClient
successfully requests an execution container from the Resource Manager. The
Application Master is provided by Giraph to manage all requests for resources
(worker nodes, memory, jar files, job configuration metadata, etc.) that
Giraph will need to perform the job. When Giraph runs in a non-YARN context,
the role of the Application Master is played by Hadoop when it launches our
GraphMappers (worker/master task nodes) to run the job.