Hadoop Common
  1. Hadoop Common
  2. HADOOP-3412

Refactor the scheduler out of the JobTracker

    Details

    • Type: Improvement Improvement
    • Status: Closed
    • Priority: Minor Minor
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 0.19.0
    • Component/s: None
    • Labels:
      None
    • Hadoop Flags:
      Reviewed
    • Release Note:
      Added the ability to chose between many schedulers, and to limit the number of running tasks per job.

      Description

      First I would like warn you that my proposition is assumed to be very naive. I just hope that reading it won't make you lose time.

      The aim

      It seems to me that improving Hadoop scheduling could be very profitable. But, it is hard to implement and compare schedulers, because the scheduling logic is mixed within the rest of the JobTracker.
      This bug is the first step of an attempt to improve the Hadoop scheduler. It re-implements the current scheduling algorithm in a separate class called JobScheduler. This new class is instantiated in the JobTracker.

      Bug fixed as a side effects

      This patch probably cannot be submited as it is.
      A first difficulty is that it does not have exactly the same behaviour than the current JobTracker. More precisely, it doesn't re-implement things like code that seems to be never called or concurency problems.
      I wrote TOCONFIRM where my proposition differ from the current implementation, so you can find them easily.
      I know that fixing bugs silently is bad. So, independently of what you decide about this patch, I will open issues for bugs that you confirm.

      Other side effects

      Another side effect of this patch is to add documentation about each step of the scheduling. I hope that it will help future improvement by lowering the level required to contribute to the scheduler.
      It also reduces the complexity and the granularity of the JobTracker (making it more parallel).

      The future

      If you feel that this is a step the right direction, I will try to propose a JobSchedulerInterface that many JobSchedulers could implement and to propose alternatives to the current « FifoJobScheduler ». If some of you have ideas about that please tell ^^ I will also open issues for things marked as FIXME in the patch.

      1. JobScheduler-v12.1.patch
        67 kB
        Tom White
      2. JobScheduler-v12.patch
        67 kB
        Tom White
      3. JobScheduler-v11.patch
        60 kB
        Tom White
      4. JobScheduler-v10.patch
        46 kB
        Tom White
      5. JobScheduler-v9.2.patch
        29 kB
        Matei Zaharia
      6. JobScheduler-v9.1.patch
        37 kB
        Tom White
      7. JobScheduler-v9.patch
        37 kB
        Tom White
      8. JobScheduler_v8.patch
        57 kB
        Brice Arnould
      9. JobScheduler_v7.1.patch
        52 kB
        Brice Arnould
      10. JobScheduler_v7.patch
        50 kB
        Brice Arnould
      11. JobScheduler_v6.4.patch
        49 kB
        Brice Arnould
      12. JobScheduler_v6.3.patch
        50 kB
        Brice Arnould
      13. SimpleResourceAwareJobScheduler.java
        8 kB
        Brice Arnould
      14. JobScheduler_v6.2.patch
        46 kB
        Brice Arnould
      15. JobScheduler_v6.1.patch
        41 kB
        Brice Arnould
      16. JobScheduler_v6.patch
        40 kB
        Brice Arnould
      17. JobScheduler_v5.patch
        40 kB
        Brice Arnould
      18. RackAwareJobScheduler.java
        2 kB
        Brice Arnould
      19. JobScheduler_v4.patch
        37 kB
        Brice Arnould
      20. JobScheduler_v3b.patch
        39 kB
        Brice Arnould
      21. JobScheduler_v3.patch
        39 kB
        Brice Arnould
      22. JobScheduler_v2.patch
        34 kB
        Brice Arnould
      23. JobScheduler.patch
        30 kB
        Brice Arnould

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            • Assignee:
              Brice Arnould
              Reporter:
              Brice Arnould
            • Votes:
              1 Vote for this issue
              Watchers:
              20 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved:

                Development