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#openstack-nova - 2018-08-07
14:59:42 stephenfin *yup
14:59:45 dansmith sean-k-mooney: but most of that is waiting for IO so it's not keeping the process busy
14:59:47 mdbooth lyarwood: I have another meeting now, so I've chucked a brain dump in the functional failure review.
14:59:56 efried stephenfin: My understanding is that POWER handles NUMA under the covers, and does it well enough that the deployer doesn't need control.
15:00:07 sean-k-mooney stephenfin: numa is exposed to linux via the bios so it should would the same on powerpc
15:00:27 sean-k-mooney the quest is does the hypervior expose it or not
15:00:30 stephenfin efried: Is that the hardware doing the work or the hypervisor?
15:00:33 stephenfin sean-k-mooney: yeah ^
15:00:46 stephenfin (the work of abstracting NUMA'ness)
15:01:25 sean-k-mooney dansmith: good point it shoudl yeild exection
15:01:40 jaypipes cdent, dansmith: is there any reason now that placement claims are doing most of the resource consumption work (in an atomic manner) that we can't set the update_available_resource default to something sensible like 15 minutes?
15:02:42 sean-k-mooney jaypipes: just trying to think is there any late claim still dont in the compute node. i think not
15:02:50 cdent there's not
15:02:52 dansmith jaypipes: I would have to look, because I think we have other things hung off that process
15:03:27 cdent jaypipes: do we do anything with host states and Filters where that info needs to be up to date?
15:03:38 cdent non-placement-related filtering
15:03:59 sean-k-mooney stephenfin: im pretty sure that hyperv hides the numa info from nova
15:04:24 jroll jaypipes: one catch would be picking up new/changed ironic nodes, but maybe we can just doc that caveat
15:04:34 sean-k-mooney stephenfin: i know they have made numa affinity of instance memory a hypervir config option
15:04:46 openstackgerrit Lee Yarwood proposed openstack/nova master: WIP libvirt: Reduce calls to qemu-img during update_available_resource https://review.openstack.org/589513
15:05:00 jroll "changed" e.g. ironic node goes to / comes out of maintenance mode
15:05:05 lyarwood s10: ^ we can remove half of the qemu-img calls with that
15:07:29 stephenfin sean-k-mooney: Fair enough. I was trying to write a high-level overview of NUMA but needed to figure out what platforms would be affected. I'll just leave that piece out :)
15:08:22 sean-k-mooney stephenfin: i would recommend putting it in the context of which hypervior rather then which plathform e.g. achitecuter if you do
15:09:50 sean-k-mooney i would expect power-kvm via libvirt to work the same as kvm on x86 but i would expect powervm direct driver to work very different
15:11:18 stephenfin sean-k-mooney: Good call. I'll do that
15:11:29 cdent jaypipes: we could consider have a different periodic job for the placement calls? There's a bazillion periodic jobs in the compute manager already, aren't there? What's one more :()
15:12:25 sean-k-mooney cdent: they mainly all share the same config option today however. we dont have a interval time option for each
15:12:56 sean-k-mooney that said i dont see an issue with adding a new config option and default it to the current periodic job interval
15:13:30 sean-k-mooney or if you want the behavior change to be implicit on upgrade then default to 15 mins or whatever makes sense
15:13:51 cdent sean-k-mooney: there are several *_internal conf settings in nova/conf/compute.py and they all fall back to the default for any periodic in an oslo_service based service
15:14:06 cdent s/_internal/_interval/
15:15:58 efried stephenfin, sean-k-mooney: Sorry, had to step away for a sec. From your point of view, the "hardware" and the "hypervisor" are the same thing.
15:16:35 sean-k-mooney efried: meaning we cant see the hardware so we should only care about what the hypervior reporst
15:17:12 efried sean-k-mooney: That's probably a sane way to think about it. I don't think the hypervisor reports NUMA cells at all. You see procs and memory.
15:17:27 efried I'm not an expert here, for sure.
15:17:54 sean-k-mooney efried: that is how the host is reported form hyperv also as far as i know
15:18:07 sean-k-mooney just one big pool for ram and cpus
15:18:39 sean-k-mooney they have a hypervior config option (not in openstack) to turn on numa affinity at the host level
15:19:11 efried yeah, see, I think NUMA affinity Just Happens (tm) on Power.
15:19:12 jaypipes cdent: perhaps, yes
15:19:38 sean-k-mooney efried: i dont think vsphere exposes it either. its just libvirt that exposes it as far as i can tell
15:19:55 efried frickin libvirt <rolls eyes>
15:20:43 sean-k-mooney hehe well libvirt exposes it because libvirt is not a hypervior its an hypervior abstraction layer and isnce qemu does not do this by default it fell to nova to fill in the gapps
15:21:04 efried :)
15:22:08 jaypipes sean-k-mooney: WRONG! libvirt is an XML file management system.
15:22:40 sean-k-mooney jaypipes: lol
15:22:58 sean-k-mooney jaypipes: it does a little bit more then that but more or less
15:24:24 sean-k-mooney you know it could be argured that a new service could be insrted between nova and libvirt that did all the nfv stuff and the libvirt driver could be made way simpeler
15:25:24 cdent I sure hope those unicorns are free range
15:35:10 s10 lyarwood: with https://review.openstack.org/589513 update_available_resource() lasts 10 seconds for 100 instances instead of 20 seconds without.
15:39:13 lyarwood s10: kk, that's a single qemu-img info call per disk to avoid the other issues fixed by the original changes
15:39:52 dansmith s10: this sounds like a silly question, but what does it matter how long that takes?
15:39:57 dansmith it's not blocking other work right?
15:40:36 efried stephenfin: I think https://review.openstack.org/#/c/588422/ is ready for your +A now
15:40:46 stephenfin ack
15:40:53 lyarwood dansmith: I did ask above and it's causing issues with LM apparently
15:41:09 dansmith lyarwood: oh sorry I missed that.. maybe because it's holding the RT semaphore?
15:41:42 lyarwood dansmith: yes I think so
15:41:53 dansmith okay makes sense I guess
15:42:19 dansmith lyarwood: the new call checks the allocated value, which doesn't change over the lifecycle of the image right?
15:42:54 sean-k-mooney dansmith: correct it should not
15:43:26 lyarwood dansmith: allocated can, virtual shouldn't
15:43:26 sean-k-mooney dansmith: unless the call is checking the actul used space on the host and we are not preallocting ?
15:43:36 lyarwood yeah pretty much
15:43:53 dansmith lyarwood: but which are we looking at now?
15:44:09 lyarwood dansmith: now it's just a single qemu-img info call that grabs both
15:44:15 sean-k-mooney lyarwood: the resouce track should be tracking the virtual amont right not the currently allcoated amount?
15:44:33 dansmith lyarwood: ah, both so one of them is dynamic and we can't really cache it yeah?
15:44:34 lyarwood sean-k-mooney: the allocated amount is used to work out over commit etc
15:44:58 sean-k-mooney lyarwood: that seams wrong the maxium it could use should be used for that
15:45:30 dansmith sean-k-mooney: IIRC, this is not for reporting to placement but for some of the legacy values (right lyarwood ?)
15:45:32 openstack Launchpad bug 1784826 in OpenStack Compute (nova) "Guest remain in origin host after evacuate and unset force-down nova-compute" [Undecided,In progress] - Assigned to huanhongda (hongda)
15:45:32 jaypipes dansmith: what are your thoughts on https://bugs.launchpad.net/nova/+bug/1784826? I can't tell what the expected behaviour there should be...
15:45:40 dansmith because auditing on the compute node doesn't change what placement is counting
15:46:04 lyarwood dansmith: yeah correct, this doesn't make it to placement AFAIK
15:47:04 dansmith lyarwood: so we really only need to be collecting this info for old RT, which is ignored if you don't have DiskFilter enabled, and only useful for people using the deprecated CachingScheduler yeah?
15:47:28 sean-k-mooney lyarwood: what advantage is there to using allocated though? since placement would already be using its allocation ratio to filter the hosts before the compute ever need to check its over_subsciption ratio setting
15:47:54 lyarwood dansmith: in master but this series was backported all the way back to ocata
15:48:16 lyarwood dansmith: wasn't it still used back then?
15:48:29 dansmith lyarwood: yeah I know, but diskfilter hasn't been needed since claims in the scheduler
15:48:36 dansmith *maybe* ocata, but not pike or later IIRC
15:50:40 lyarwood sean-k-mooney: right, I think the only reason this came up before is that it's visable from the CLI
15:50:46 dansmith lyarwood: anyway, just wondering if maybe we should add a workaround config tweak to disable this extra inspection so you can turn it off if you're not using DiskFilter and/or are on a new enough version
15:51:04 lyarwood dansmith: yeah that sounds like the way to go tbh
15:51:19 dansmith lyarwood: ah, well, that makes it even more pain than gain if it was just "make the numbers line up" :)
15:52:04 dansmith lyarwood: probably best to get some sign-offs from the PTL(s) of the affected releases, but that's kinda where I'm thinking
15:52:14 sean-k-mooney lyarwood: so if its visable via the cli i think thats even more reason to use the virtual not allocated disk size to have it corralte with placement
15:52:53 sean-k-mooney lyarwood: that said that would be a behavior change i guess.
15:53:22 sean-k-mooney lyarwood: i assume this is visable via the hyperviors api?
15:54:34 openstack Launchpad bug 1764489 in OpenStack Compute (nova) queens "Preallocated disks are deducted twice from disk_available_least when using preallocated_images = space" [Medium,Fix committed] - Assigned to Lee Yarwood (lyarwood)
15:54:34 lyarwood sean-k-mooney: yeah via a hypervisor-show - https://bugs.launchpad.net/nova/+bug/1764489
15:56:41 sean-k-mooney right so its messing up disk_available_least not local_gb_used...
16:01:44 openstackgerrit Balazs Gibizer proposed openstack/nova master: Use placement 1.28 in scheduler report client https://review.openstack.org/583667
16:11:02 mdbooth lyarwood: I'm partially through the functional failure. Got past the shelve/unshelve failure, error is now in _test_attach_volume_error
16:11:51 mdbooth lyarwood: However, I'm going to leave shortly, it doesn't pass yet, and there are still print statements all over it
16:12:06 melwitt .
16:12:19 mdbooth lyarwood: So I'm not inclined to push it this evening unless that would be especially helpful to you
16:15:04 lyarwood mdbooth: yeah np leave it for now
16:50:48 openstackgerrit Sergii Golovatiuk proposed openstack/nova master: Fix URI for IPv6 https://review.openstack.org/589548

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