[openstack-dev] [Nova][Neutron] nova-network in Icehouse and beyond
Daniel P. Berrange
berrange at redhat.com
Wed Jan 29 17:45:03 UTC 2014
On Wed, Jan 29, 2014 at 12:39:23PM -0500, Russell Bryant wrote:
> On 01/29/2014 12:27 PM, Daniel P. Berrange wrote:
> > On Wed, Jan 29, 2014 at 11:47:07AM -0500, Russell Bryant wrote:
> >> Greetings,
> >> A while back I mentioned that we would revisit the potential deprecation
> >> of nova-network in Icehouse after the icehouse-2 milestone. The time
> >> has come. :-)
> >> First, let me recap my high level view of the blockers to deprecating
> >> nova-network in favor of Neutron:
> >> - Feature parity
> >> - The biggest gap here has been nova-network's multi-host mode.
> >> Neutron needs some sort of HA for l3 agents, as well as the
> >> ability to run in a mode that enables a single tenant's traffic
> >> to be actively handled by multiple nodes.
> >> - Testing / Quality parity
> >> - Neutron needs to reach testing and quality parity in CI. This
> >> includes running the full tempest suite, for example. For all
> >> tests run against nova with nova-network that are applicable, they
> >> need to be run against Neutron, as well. All of these jobs should
> >> have comparable or better reliability than the ones with
> >> nova-network.
> >> - Production-ready open source components
> >> - nova-network provides basic, but usable in production networking
> >> based purely on open source components. Neutron must have
> >> production-ready options based purely on open source components,
> >> as well, that provides comparable or better performance and
> >> reliability.
> > What, no mention of providing an automated upgrade path ? Given how
> > we go to great lengths to enable continuous deployment with automated
> > upgrade paths, I'd really expect to see something to deal with migrating
> > people from nova-network to neutron with existing tenants unaffected.
> That's a good point. This is actually a very sticky situation. We have
> a upgrade path already, which is why I didn't mention it. It's not
> really great though, so it's worth further discussion. The path is roughly:
> 1) Deploy a parallel nova install that uses Neutron, but shares all
> other services with the existing Nova that uses nova-network.
> (Keystone, glance, cinder, etc)
> 2) Spawn new instances in the new Nova.
> 3) For any instances that you want to migrate over to Neutron, snapshot
> them to glance, and then re-spawn them in the new Nova.
> This is the only plan that I've heard that we *know* should work for all
> deployment variations. I've seen very little effort go into
> investigating or documenting any more advanced upgrade paths.
> The other upgrade piece is some sort of data migration. There are some
> bits of data, such as security group definitions, that we should be able
> to automatically export from nova and import into neutron. I don't
> think anyone has worked on that, either.
I was thinking of an upgrade path more akin to what users got when we
removed the nova volume driver, in favour of cinder.
ie no guest visible downtime / interuption of service, nor running of
multiple Nova instances in parallel.
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