openstack
/
nova-specs
Code Issues Proposed changes

FUP for I68498afd481f7291a6102928d7999b4be49ded7a 

This fixes some issues noted [1][2] in the above change
and also adds an explicit reminder of the RPC cast
behavior change in the REST API impact section [3].

[1] https://review.openstack.org/#/c/642807/3/specs/train/approved/cross-cell-resize.rst@35
[2] https://review.openstack.org/#/c/642807/3/specs/train/approved/cross-cell-resize.rst@494
[3] https://review.openstack.org/#/c/642807/3/specs/train/approved/cross-cell-resize.rst@582

Change-Id: I8a4489d242ef860f37498d40dd66c1f9c3f8e20c
This commit is contained in:
Matt Riedemann 2019-04-10 17:31:18 -04:00
parent 969fac8785
commit e16ede4747
1 changed files with 11 additions and 3 deletions
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14
specs/train/approved/cross-cell-resize.rst
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@ -32,7 +32,7 @@ I want to decommission old hardware in older cells and have new and existing
servers move to newer cells running newer hardware using newer flavors without
users having to destroy and recreate their workloads.
As a user, I want to my servers to retain their IPs, volumes and UUID
As a user, I want my servers to retain their IPs, volumes and UUID
while being migrated to another cell.
Proposed change
@ -154,6 +154,8 @@ There are two major reasons why we perform this check in the API:
cell). If the request is allowed to perform a cross-cell resize then we
will adjust the target host check to allow for other cells as well.
.. _api-cast:
2. Currently, the resize/migrate API actions are synchronous until conductor
RPC casts to ``prep_resize()`` on the selected target host. This could be
problematic during a cross-cell resize if the conductor needs to validate
@ -451,6 +453,8 @@ Known issues
recording a ``compute_prep_resize`` event when calling the
``prep_snapshot_based_resize_at_dest`` method.
.. _personality-files:
3. Servers created with personality files, commonly known as file injection,
that are resized across cells will lose the personality files since they are
not persisted in the database. There are two ways to view this. First is
@ -491,8 +495,6 @@ Edge cases
cell DB, update the ``MigrationContext.migration_id`` to match the
``Migration.id`` of the source cell migration record.
.. _personality-files:
3. It is possible to attach/detach volumes to/from a resized server. Because of
this, mirroring those block device mapping changes from the target cell DB
to the source cell DB during revert adds complication but it is
@ -580,6 +582,12 @@ While the instance is resized and contains records in both cells, the API will
have to take care to filter out duplicate instance and migration records while
listing those across cells (using the ``hidden`` field).
As noted :ref:`above <api-cast>`, if cross-cell resize is allowed the API
service will asynchronously cast to the conductor service rather than RPC
call and block the HTTP response until a target host is chosen. Regardless
of this the ``resize`` and ``migrate`` server action API response status code
is always a 202.
Security impact
---------------