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This describes how the state machine works internally. What is important to know is that the addTransition method takes the preState, postState, eventType, and transition. The transition is an object whose transition method will be called during the doTransition method (called by the event handler).
Hadoop MapReduce State Machine Redundancy
JobImpl
| Count | Transition | Trigger (Event/State) | Comment |
|---|---|---|---|
| 12 | DIAGNOSTIC_UPDATE_TRANSITION | JobEventType.JOB_DIAGNOSTIC_UPDATE | Same for most named states (JobImpl) |
| 14 | COUNTER_UPDATE_TRANSITION | JobEventType.JOB_COUNTER_UPDATE | |
| 13 | INTERNAL_ERROR_TRANSITION | JobEventType.INTERNAL_ERROR | InternalErrorTransition extends InternalTerminationTransition by setting the error into the history string. |
| 5 | INTERNAL_REBOOT_TRANSITION | JobEventType.JOB_AM_REBOOT | InternalRebootTransition extends InternalTerminationTransition by setting the error in the history string. |
| 2 | TASK_ATTEMPT_COMPLETED_EVENT_TRANSITION | JobEventType.JOB_TASK_ATTEMPT_COMPLETED | |
| 2 | KilledDuringAbortTransition() | JobEventType.JOB_KILL | From FAIL_WAIT and FAIL_ABORT |
| 2 | JobAbortCompletedTransition() | JobEventType.JOB_ABORT_COMPLETED | From FAIL_ABORT and KILL_ABORT |
TaskImpl
| Count | Transition | Trigger | Comment |
|---|---|---|---|
| 2 | KILL_TRANSITION | TaskEventType.T_KILL | |
| 2 | ATTEMPT_KILLED_TRANSITION | TaskEventType.T_ATTEMPT_KILLED | |
| 2 | AttemptFailedTransition() | TaskEventType.T_ATTEMPT_FAILED |
TaskAttemptImpl
| Count | Transition | Trigger | Comment |
|---|---|---|---|
| 2 | RequestContainerTransition() | TaskAttemptEventType.TA_SCHEDULE TaskAttemptEventType.TA_RESCHEDULE | A bool is passed to the constructor to do cleanup in one case and no the other |
| 4 | KilledTransition() | TaskAttemptEventType.TA_KILL TaskAttemptEventType.TA_CONTAINER_CLEANED TaskAttemptEventType.TA_CLEANUP_DONE | |
| 2 | FailedTransition() | TaskAttemptEventType.TA_FAILMSG TaskAttemptEventType.TA_CLEANUP_DONE | |
| 13 | DIAGNOSTIC_INFORMATION_UPDATE_TRANSITION | TaskAttemptEventType.TA_DIAGNOSTICS_UPDATE | |
| 3 | DeallocateContainerTransition() | TaskAttemptEventType.TA_KILL TaskAttemptEventType.TA_FAILMSG TaskAttemptEventType.TA_CONTAINER_LAUNCH_FAILED | Constructor takes a bool that will "send event to speculator that we withdraw our container needs, if we're transitioning out of UNASSIGNED" |
| 13 | CLEANUP_CONTAINER_TRANSITION | TaskAttemptEventType.TA_CONTAINER_COMPLETED TaskAttemptEventType.TA_KILL TaskAttemptEventType.TA_FAILMSG TaskAttemptEventType.TA_DONE TaskAttemptEventType.TA_TIMED_OUT | |
| 2 | StatusUpdater() | TaskAttemptEventType.TA_UPDATE | |
| 2 | TaskCleanupTransition() | TaskAttemptEventType.TA_CONTAINER_CLEANED |
Additional Notes:
- Event "ignore" lists is necessary in this implementation for events that come in that shouldn't affect the state machine.
No support list in Python MapReduce
- Diagnostics/Logs
- Counters
- Doesn't support reboot