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https://issues.apache.org/jira/browse/MAPREDUCE-3098?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13116126#comment-13116126
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Vinod Kumar Vavilapalli commented on MAPREDUCE-3098:
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bq. True however what this actually represents is the state of the current
attempt's AM.
That's not true and which I am trying to impress upon. ApplicationState.New and
ApplicationState.SUBMITTED don't even represent any state of the AM.
ApplicationState.RUNNING means multiple things: it may be that an AM is
running, or it may also mean that AM is down and in the process of restarting.
ApplicationState.FAILED may actually mean that the platform is not even able to
launch the AM for some reason.
To be semantically correct, RMAppAttemptState represents the AM state,
ApplicationState is much more than RMAppAttemptState, it subsumes the whole
application including any and all app-attempts.
bq. A submitted/running/completed AM only really implies the state of the AM
and it would be better if we changed this from ApplicationState to
ApplicationMasterState to avoid confusion as to what it really implies.
Ditto. Like I pointed above, ApplicationState.Running doesn't map directly to a
running AM, neither does ApplicationState.FAILED represent actual job-failure.
bq. From the perspective of a client, a client would prefer to assume that the
application 'finish' state is whether my "job" completed successfully or not.
Not sure if you worked with other resource-managers which give you an ability
to run your own code. In torque, for example, the corresponding state for
ApplicationState.FINISHED only means the app has finished. To know what
happened to your actual job, you need a separate state.
bq. The RM does not need to act on it today so a string should work. However,
the question is whether using a flexible string/blob based approach is the way
to go? I, in particular, do not have any preference over string/enum.
I prefer the blob approach as having an enum is stricter and obviously we
cannot have an enum representing final-states for all possible frameworks.
bq. A client would monitoring AppMasterState for completion (
succeeded/failed/killed ) and if succeeded, look at the ApplicationFinishState
to actually verify that the work was done successfully.
Given above, a client would be instead monitoring for ApplicationState, if it
is one of the final states SUCCEEDED, FAILED or KILLED, it will look at the
corresponding ApplicationReport.FinalFrameworkState to see what actually
happened to the job.
Apologies if I am giving an impression of creating a storm. But honestly all of
this was thought through earlier end-to-end and I firmly belive that the
current states and records represent the correct abstraction.
> Report Application status as well as ApplicationMaster status in
> GetApplicationReportResponse
> ----------------------------------------------------------------------------------------------
>
> Key: MAPREDUCE-3098
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-3098
> Project: Hadoop Map/Reduce
> Issue Type: Sub-task
> Components: mrv2
> Affects Versions: 0.23.0
> Reporter: Hitesh Shah
> Assignee: Hitesh Shah
> Priority: Blocker
> Fix For: 0.23.0
>
>
> Currently, an application report received by the client from the RM/ASM for a
> given application returns the status of the application master. It does not
> return the status of the application i.e. whether that particular job
> succeeded or failed.
> The AM status would be one of FINISHED (SUCCEEDED should be renamed to
> FINISHED as AM state does not indicate overall success/failure), FAILED or
> KILLED.
> The final state sent by the AM to the RM in the
> FinishApplicationMasterRequest should be exposed to the client as
> ApplicationState.
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