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#openstack-nova - 2019-02-14
16:14:26 bauzas efried: there could be a race tho
16:14:28 efried bauzas: Also, pretty sure we run upt right before spawn, not just in the periodic, I could be wrong. So it should be pretty durn recent by then.
16:14:46 bauzas efried: where spawn() could run *before* upt
16:14:48 bauzas yeah
16:14:56 efried bauzas: But like I've said already (uh, possibly about something else): if there's a race, it's going to f up more than just this.
16:15:06 mriedem we run update_available_resource on compute start
16:15:08 mriedem which calls upt
16:15:11 bauzas i know
16:15:13 mriedem that's before the service is ready for spawn
16:15:15 mriedem so what's the issue
16:15:18 bauzas okay
16:15:33 bauzas I thought we were allowing instances to spawn, while compute was starting
16:15:41 mriedem f i hope not
16:15:46 mriedem https://github.com/openstack/nova/blob/master/nova/compute/manager.py#L1259
16:15:57 mriedem https://github.com/openstack/nova/blob/master/nova/service.py#L180
16:16:08 bauzas oh good catch this is pre hook
16:16:12 bauzas perfect
16:16:35 bauzas mriedem: you're not worried by libvirt keeping a copy of the provider tree structure ?
16:16:47 mriedem i haven't been following along
16:17:07 bauzas mriedem: nah, it's just because we need to find the name of a RP by its uuid
16:17:08 mriedem sounds like more cache-tastic fun
16:17:24 bauzas mriedem: as we only get RP UUID from the allocations list we pass over spawn
16:17:28 mriedem which RP?
16:17:30 efried mriedem: TL;DR: the virt driver needs to be responsible for maintaining a mapping between RP and "real thing". The provider tree already has that information, so don't bother building something special, just save it off during upt.
16:17:47 bauzas mriedem: the RP which was allocated a VGPU
16:17:55 mriedem so the pgpu?
16:17:58 mriedem the child provider
16:18:01 bauzas yup
16:18:15 bauzas so that libvirt can use or create a mdev from *this* pgpu
16:18:25 bauzas http://paste.openstack.org/show/745109/
16:18:44 mriedem what's the alternative? the driver holding it's own mapping of rp_uuid -> rp_name? which is something ProviderTree already does
16:18:49 efried yes ^
16:18:56 bauzas above is the fact that when we create a new instance, we use a random mdev which is unrelated to the pgpu which was allocated by placement
16:18:56 efried (to both)
16:19:25 mriedem i don't have a strong feeling either way
16:19:46 mriedem ProviderTree is convenient albeit heavy weight and hopefully someone doesn't abuse it somehow, but doing our own mapping dict is redundant
16:19:49 mriedem so shrug
16:20:07 bauzas yeah me too, but I'm opinionated enough to make it the smoothiest
16:20:30 bauzas and caching the value in the libvirt driver object seems the smoothiest approach
16:20:45 mriedem so the provider tree would just get reset on every upt call?
16:20:47 mriedem if so, then sure
16:20:51 bauzas yeah
16:20:54 mriedem wfm
16:21:02 bauzas i'm done with complex cache invalidation mechanisms
16:21:13 mriedem are you SO done with them?
16:25:21 bauzas mriedem: /me tries to not think hard of AZs
16:25:34 bauzas or server groups
16:25:47 mriedem hey if you like azs i have some good news for you
16:25:48 mriedem https://review.openstack.org/#/c/509206/
16:25:51 mriedem finally fixing that shitty old bug
16:26:35 bauzas \o/
16:26:46 bauzas mriedem: straight adding it into my queue
16:27:39 bauzas gibi: you'll be happy to hear that functests work now, btw. :)
16:28:07 gibi bauzas: awesome
16:29:24 gibi every time I start kicking https://review.openstack.org/#/c/635859/ I got depressed after 15 minutes about I capabilities to understand what happening
16:29:38 melwitt o/
16:30:14 melwitt gibi: me too. I tried for awhile and gave up
16:31:31 gibi melwitt: but I feel something deep is behind that so I cannot gave up :)
16:32:09 melwitt gibi: that's good, I think you will get to the bottom of it :)
16:32:20 mriedem well if you want to get really depressed http://logs.openstack.org/47/635147/11/check/nova-tox-functional-py35/5c3c2a9/job-output.txt.gz#_2019-02-13_13_33_41_103932
16:32:34 mriedem that traceback wins the grand prize
16:32:41 mriedem and i don't know what to do about it
16:32:48 mriedem looks like the db dropped in the middle of the test
16:33:32 gibi mriedem: nice :)
16:33:56 mriedem the dumping of os-traits contents to the logs on each functional test run with the PlacementFixture isn't helping either
16:34:08 mriedem http://logs.openstack.org/47/635147/11/check/nova-tox-functional-py35/5c3c2a9/job-output.txt.gz#_2019-02-13_13_33_41_193979
16:34:24 gibi mriedem: I think we can move that to DEBUG
16:35:18 mriedem yeah probably http://logs.openstack.org/59/636459/2/check/tempest-full/3226eb1/controller/logs/screen-placement-api.txt.gz#_Feb_13_13_54_30_464250
16:35:23 gibi I'm affraid that the drop of the databease could be another interfering test case. Did you managed to reproduce that locally?
16:35:31 mriedem nope
16:35:35 bauzas gibi: efried: what's the best way to copy a providertree object ? copy.deepcopy() ?
16:35:54 openstackgerrit Elod Illes proposed openstack/nova master: DNM: test pip 19 - pip freeze with git editable https://review.openstack.org/636980
16:35:56 bauzas or do we have other built-in mechanism ?
16:36:18 bauzas tbc, I want to have a separate reference to be stored on the libvirt object
16:36:54 gibi bauzas: I would be affraid of copying the self.lock = lockutils.internal_lock(_LOCK_NAME) inside the ProviderTree
16:37:25 efried bauzas: upt is already operating on a copy... but I'm actually not positive that ufpt doesn't dork with it. So yeah, copy.deepcopy is probably the best bet.
16:37:58 gibi bauzas: besides the self.lock the rest of the internals seems copiable
16:38:18 bauzas gibi: so, ideally we should provide a copy method
16:38:19 efried gibi: hm, interesting point about the lock. This impl that bauzas is doing should be read-only. But that still wouldn't stop you from bouncing off the lock if the other instance is using it.
16:38:38 bauzas efried: what I want is purely read-only
16:38:45 efried However, I would be surprised if the lockutils lock doesn't override __copy__ to *not* copy itself.
16:38:49 bauzas actually, you know what ? I'm gonna make it explicit
16:38:55 bauzas by using a propertgy
16:39:11 bauzas we're not intended to manipulate this copy
16:39:12 gibi mriedem: I think I will stick to the remove-the-assert-that-blow-the-world issue, that I can reproduce locally at least
16:39:59 efried bauzas: There are methods to get a read-only copy of the data out of ProviderTree, but I'm pretty sure they only get one provider at a time.
16:40:22 efried Yeah, ProviderTree.data()
16:40:27 mriedem gibi: efried: fwiw i'm also holding off on the bw provider series until https://review.openstack.org/#/c/616239/ makes progress
16:40:40 mriedem and we've got 3 weeks from FF today
16:40:52 efried I guess that's my action
16:41:16 mriedem i'm just waiting for efried to +2 so i can nit pick a few things and make it look like i get it
16:41:17 gibi efried: thanks
16:41:21 bauzas efried: anyway, I'm rushing to propose a new rev
16:41:35 bauzas efried: you will be able to comment on the best approach by reviewing
16:41:41 bauzas not a big deal
16:41:50 gibi efried: to your surprise there is no copy overried in https://github.com/openstack/oslo.concurrency/blob/master/oslo_concurrency/lockutils.py ;)
16:41:57 efried gibi: d'oh!
16:44:11 efried uh, wtf. gibi, bauzas, when I try to deepcopy an object with a lockutils.internal_lock in it, I get an error.
16:44:35 efried so how tf would that be working in the rt? /me looks...
16:51:02 efried gibi, bauzas: http://paste.openstack.org/show/745111/ <== so how tf is https://github.com/openstack/nova/blob/master/nova/scheduler/client/report.py#L885 working??

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