On 9/23/2015 2:45 PM, John Griffith wrote:
On Wed, Sep 23, 2015 at 1:34 PM, Matt Riedemann <mrie...@linux.vnet.ibm.com <mailto:mrie...@linux.vnet.ibm.com>> wrote: On 9/23/2015 2:15 PM, Matt Riedemann wrote: On 9/23/2015 1:46 PM, Ivan Kolodyazhny wrote: Hi Matt, In Liberty, we introduced allow_availability_zone_fallback [1] option in Cinder config as fix for bug [2]. If you set this option, Cinder will create volume in a default AZ instead of set volume into the error state [1] https://github.com/openstack/cinder/commit/b85d2812a8256ff82934d150dbc4909e041d8b31 [2] https://bugs.launchpad.net/cinder/+bug/1489575 Regards, Ivan Kolodyazhny On Wed, Sep 23, 2015 at 9:00 PM, Matt Riedemann <mrie...@linux.vnet.ibm.com <mailto:mrie...@linux.vnet.ibm.com> <mailto:mrie...@linux.vnet.ibm.com <mailto:mrie...@linux.vnet.ibm.com>>> wrote: I came across bug 1496235 [1] today. In this case the user is booting an instance from a volume using source=image, so nova actually does the volume create call to the volume API. They are booting the instance into a valid nova availability zone, but that same AZ isn't defined in Cinder, so the volume create request fails (since nova passes the instance AZ to cinder [2]). I marked this as invalid given how the code works. I'm posting here since I'm wondering if there are alternatives worth pursuing. For example, nova could get the list of AZs from the volume API and if the nova AZ isn't in that list, don't provide it on the volume create request. That's essentially the same as first creating the volume outside of nova and not specifying an AZ, then when doing the boot from volume, provide the volume_id as the source. The question is, is it worth doing that? I'm not familiar enough with how availability zones are meant to work between nova and cinder so it's hard for me to have much of an opinion here. [1] https://bugs.launchpad.net/nova/+bug/1496235 [2] https://github.com/openstack/nova/blob/master/nova/virt/block_device.py#L381-L383 -- Thanks, Matt Riedemann __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe <http://openstack-dev-requ...@lists.openstack.org?subject:unsubscribe> <http://openstack-dev-requ...@lists.openstack.org?subject:unsubscribe> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe <http://openstack-dev-requ...@lists.openstack.org?subject:unsubscribe> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev Sorry but that seems like a hack. I'm trying to figure out the relationship between AZs in nova and cinder and so far no one seems to really know. In the cinder IRC channel I was told there isn't one, which would mean we shouldn't even try creating the volume using the server instance AZ. Also, if there is no relationship, I was trying to figure out why there is the cinder.cross_az_attach config option. That was added in grizzly [1]. I was thinking maybe it was a legacy artifact from nova-volume, but that was dropped in grizzly. So is cinder.cross_az_attach even useful? [1] https://review.openstack.org/#/c/21672/ The plot thickens. I was checking to see what change was made to start passing the server instance az on the volume create call during boot from volume, and that was [1] which was added in kilo to fix a bug where boot from volume into a nova az will fail if cinder.cross_az_attach=False and storage_availability_zone is set in cinder.conf. So I guess we can't just stop passing the instance az to the volume create call. But what I'd really like to know is how this is all used between cinder and nova, or was this all some work done as part of a larger effort that was never completed? Basically, can we deprecate the cinder.cross_az_attach config option in nova and start decoupling this code? [1] https://review.openstack.org/#/c/157041/ -- Thanks, Matt Riedemann __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe <http://openstack-dev-requ...@lists.openstack.org?subject:unsubscribe> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev To be honest this is probably my fault, AZ's were pulled in as part of the nova-volume migration to Cinder and just sort of died. Quite frankly I wasn't sure "what" to do with them but brought over the concept and the zones that existing in Nova-Volume. It's been an issue since day 1 of Cinder, and as you note there are little hacks here and there over the years to do different things. I think your question about whether they should be there at all or not is a good one. We have had some interest from folks lately that want to couple Nova and Cinder AZ's (I'm really not sure of any details or use-cases here). My opinion would be until somebody proposes a clear use case and need that actually works that we consider deprecating it. While we're on the subject (kinda) I've never been a very fond of having Nova create the volume during boot process either; there's a number of things that go wrong here (timeouts almost guaranteed for a "real" image) and some things that are missing last I looked like type selection etc. We do have a proposal to talk about this at the Summit, so maybe we'll have a descent primer before we get there :) Thanks, John __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
Heh, so when I just asked in the cinder channel if we can just deprecate nova boot from volume with source=(image|snapshot|blank) (which automatically creates the volume and polls for it to be available) and then add a microversion that doesn't allow it, I was half joking, but I see we're on the same page. This scenario seems to introduce a lot of orchestration work that nova shouldn't necessarily be in the business of handling.
-- Thanks, Matt Riedemann __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
