yahoo-eng-team team mailing list archive

[Paul Carlton <paul.carlton2@xxxxxxx>]

Public bug reported:

migration of shutdown instances doesn't exclude the current compute host
in the conductor so given two instances with an affinity policy the host
that is chosen will always be the current host which leads to an
exception being generated on the compute host in prep_resize method.
This causes the migration to fail and thus place the instance in an
error state.

We should modify the conductor task code to assess if the operation is a
resize (in which case the same host is allowed) and if not exclude the
current host (as is done for live migration).

A wider issue here is the migration of instances with affinity policy,
seem to me there should be some option to override it to allow for the
migration of these instances.  Live Migration supports a force option
but that overrides the scheduler completely which is not an ideal
solution.  Cold migration provides no such option, effectively meaning
the migration of instances with affinity policy is not possible when
multiple instances with the same group membership exist.

** Affects: nova
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1608832

Title:
  cold migration of instances with affinity policy fails

Status in OpenStack Compute (nova):
  New

Bug description:
  migration of shutdown instances doesn't exclude the current compute
  host in the conductor so given two instances with an affinity policy
  the host that is chosen will always be the current host which leads to
  an exception being generated on the compute host in prep_resize
  method.  This causes the migration to fail and thus place the instance
  in an error state.

  We should modify the conductor task code to assess if the operation is
  a resize (in which case the same host is allowed) and if not exclude
  the current host (as is done for live migration).

  A wider issue here is the migration of instances with affinity policy,
  seem to me there should be some option to override it to allow for the
  migration of these instances.  Live Migration supports a force option
  but that overrides the scheduler completely which is not an ideal
  solution.  Cold migration provides no such option, effectively meaning
  the migration of instances with affinity policy is not possible when
  multiple instances with the same group membership exist.

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