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[Bug 1796192] Re: online_data_migrations exceptions quietly masked

 

Reviewed:  https://review.openstack.org/611463
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=d47486d317e8cdb1cdab50d73f6484289ab082d4
Submitter: Zuul
Branch:    master

commit d47486d317e8cdb1cdab50d73f6484289ab082d4
Author: imacdonn <iain.macdonnell@xxxxxxxxxx>
Date:   Wed Oct 17 22:48:18 2018 +0000

    cinder-manage online_data_migrations fixes
    
    Addresses some issues with this command:
    
    1) When used without the --max-count option, the summary table will
       always show zero migrations run, because it only accounts for the
       last batch, and the loop only exits when the last batch does no work.
    
    2) "remaining" counts cannot be accurate, given the way migrations are
       implemented, because the "found" count refers to the number of rows
       that exist in the database, not the number that still need the
       migration applied.
    
    3) In the case where no migrations are successful, but some raise
       exceptions, the command was exiting with status zero, which usually
       indicates "success". This can cause issues that cause migration
       failures to go unnoticed, especially when automated.
    
    4) When exceptions do occur, a minimally useful message is output, and
       no detail about the exception is available to the user. The exception
       detail should be logged.
    
    5) Inaccuracies in the documentation - "--max_number" should be
       "--max-count", and stale references to the "--ignore_state" option,
       which was removed in [1]
    
    The solution for (3) introduces a new exit status, 2. See release note
    for details.
    
    These changes are aligned with equivalents [2][3] for the nova-manage
    command, except for the calculation of "Total Needed" - nova seems to
    interpret the "found" count differently/inconsistently.
    
    [1] https://review.openstack.org/510201
    [2] https://review.openstack.org/605828
    [3] https://review.openstack.org/608091
    
    Change-Id: I878480eb2359625cde839b073230844acc645cba
    Closes-Bug: #1794364
    Closes-Bug: #1796192


** Changed in: cinder
       Status: In Progress => Fix Released

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https://bugs.launchpad.net/bugs/1796192

Title:
  online_data_migrations exceptions quietly masked

Status in Cinder:
  Fix Released
Status in OpenStack Compute (nova):
  Fix Released

Bug description:
  When online_data_migrations raise exceptions, nova/cinder-manage
  catches the exception, prints a fairly useless "something didn't work"
  message, and moves on. Two issues:

  1) The user(/admin) has no way to see what actually failed (exception is not logged)
  2) The command returns exit status 0, as if all possible migrations have been completed successfully - this can cause failures to get missed, especially if automated

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References