openstack
/
nova
Code Issues Proposed changes

cells: document upgrade limitations/assumptions 

We log a warning when using cells that it's experimental, and we have
several locations in the docs that say it's experimental, but we have
never documented that rolling upgrades are not supported and that cells
deployments must be upgraded in lockstep.  This adds that information to
the warning that's logged on startup and to the devref doc on upgrades
so people know that cells is still a special kitten that must be treated
differently.

Related-Bug: #1479181

Change-Id: Idd57f8daa308543a1733092f427e41b1a205b1d1
This commit is contained in:
Matt Riedemann 2015-07-29 07:30:38 -07:00
parent 65d4884199
commit c15a639dea
2 changed files with 10 additions and 1 deletions
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6
doc/source/upgrade.rst
View File

@ -76,6 +76,12 @@ RPC version pinning
are able to be upgraded.
https://wiki.openstack.org/wiki/RpcMajorVersionUpdates
.. note::
This does not apply to cells deployments since cells does not currently
support rolling upgrades. It is assumed that cells deployments are
upgraded in lockstep so n-1 cells compatibility does not work.
Online Configuration Reload
During the upgrade, we pin new serves at the older RPC version. When all
services are updated to use newer code, we need to unpin them so we are

5
nova/cells/manager.py
View File

@ -84,7 +84,10 @@ class CellsManager(manager.Manager):
'less testing than the rest of Nova. This may change '
'in the future, but current deployers should be aware '
'that the use of it in production right now may be '
'risky.'))
'risky. Also note that cells does not currently '
'support rolling upgrades, it is assumed that cells '
'deployments are upgraded lockstep so n-1 cells '
'compatibility does not work.'))
# Mostly for tests.
cell_state_manager = kwargs.pop('cell_state_manager', None)
super(CellsManager, self).__init__(service_name='cells',