What's the difference between YarnApplicationState and FinalStatus?

Question

According to Yarn document, YarnApplicationState is the state of application reported by ResourceManager, while FinalStatus is the final status of application reported by ApplicationMaster itself. Sometimes while YarnApplicationState is SUCCEEDED, FinalStatus of the application could be FAILED. So what's the difference between these two status? And which one can decide whether the task is executed successfully?

Answer 1

The Resource Manager reflects the Application's status regarding YARN answering the following question:

Did the application complete properly?  Did all the mapper and reducer tasks complete?

While the AM's FinalStatus can reflect whether the application's purpose succeeded answering the following question:

Did it produce the right output?  Was it able to write output to HDFS?