[openstack-dev] The state of nova-network to neutron migration

Thierry Carrez thierry at openstack.org
Fri Jan 9 10:04:56 UTC 2015

Maru Newby wrote:
>> On Jan 8, 2015, at 3:54 PM, Sean Dague <sean at dague.net> wrote:
>> The crux of it comes from the fact that the operator voice (especially
>> those folks with large nova-network deploys) wasn't represented there.
>> Once we got back from the mid-cycle and brought it to the list, there
>> was some very understandable push back on deprecating without a
>> migration plan.
> I think it’s clear that a migration plan is required.  An automated migration, not so much.

The solution is not black or white.

Yes, operators would generally prefer an instant, automated, no-downtime
"hot" migration that magically moves them to the new world order. Yes,
developers would generally prefer to just document a general "cold"
procedure that operators could follow to migrate, warning that their
mileage may vary.

The trade-off solution we came up with last cycle is to have developers
and operators converge on a clear procedure with reasonable/acceptable
downtime, potentially assisted by new features and tools. It's really
not a "us vs. them" thing. It's a collaborative effort where operators
agree on what level of pain they can absorb and developers help to
reduce that pain wherever reasonably possible.

This convergence effort is currently rebooted because it has stalled. We
still need to agree on the reasonable trade-off procedure. We still need
to investigate if there is any tool or simple feature we can add to
Neutron or Nova to make some parts of that procedure easier and less

So we are not bringing back the magic upgrade pony requirement on the
table. We are just rebooting the effort to come to a reasonable solution
for everyone.

Thierry Carrez (ttx)

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