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#openstack-nova - 2020-05-11
11:02:21 gibi lyarwood: for me either the size of the cache should be configurable (and then we can account for that in reserved_host_disk_mb) or nova needs to report cached disk usage as used in placement
11:02:52 lyarwood gibi: yeah I'd say the latter, I honestly thought we did already.
11:04:25 gibi lyarwood: this is a bug in pike for one of our customers so I also have to think about a backportable solution
11:04:58 gibi lyarwood: do you think that determining the size of the image cache is easy?
11:05:18 gibi is it just some file system calls in the _base dir, isn't it?
11:05:48 lyarwood gibi: yes for file based backends
11:06:27 gibi I have close to zero knowledge on non file based backends behavior
11:07:13 lyarwood gibi: we don't cache in rbd iirc
11:07:33 gibi is there a way to turn of the cache?
11:07:53 gibi for file based backend? (that would be a workaround in my downstream issue)
11:09:48 lyarwood gibi: I don't think so, you can disable the manager but I think we still cache things at creation time
11:10:00 lyarwood gibi: the manager just doesn't run to clean things up
11:10:20 gibi lyarwood: thanks
11:57:19 openstackgerrit Sasha Andonov proposed openstack/nova master: rbd_utils: increase _destroy_volume timeout https://review.opendev.org/705764
12:07:09 nightmare_unreal how can I determine default api version used by osc CLI ? suppose if we don't specify --os-compute-api-version , which version will it take and how it's determined ?
12:10:14 lyarwood nightmare_unreal: https://docs.openstack.org/api-guide/compute/microversions.html#version-discovery - I think there's also an osc command for that
12:10:36 nightmare_unreal Thanks :)
12:52:10 openstackgerrit Stephen Finucane proposed openstack/nova master: docs: Note the ``hw_numa_nodes`` image property https://review.opendev.org/683849
13:34:25 openstackgerrit Stephen Finucane proposed openstack/nova master: SR-IOV passthrough: Check PF only if VF is enabled https://review.opendev.org/476642
13:36:19 jsuchome dansmith: Hi, I've updated related patchets about that direct rbd download (including the spec) could you give it another look?
13:46:17 openstackgerrit Stephen Finucane proposed openstack/nova master: Poison netifaces.interfaces() in tests https://review.opendev.org/671773
13:46:51 dansmith jsuchome: yep will queue for today
13:51:52 openstackgerrit Stephen Finucane proposed openstack/nova master: Raise if flavor and image disagree on hide_hypervisor_id https://review.opendev.org/663365
14:17:16 openstackgerrit Lee Yarwood proposed openstack/nova stable/train: Revert "nova shared storage: rbd is always shared storage" https://review.opendev.org/726861
14:17:35 openstackgerrit Lee Yarwood proposed openstack/nova stable/stein: Revert "nova shared storage: rbd is always shared storage" https://review.opendev.org/726862
14:17:50 openstackgerrit Lee Yarwood proposed openstack/nova stable/rocky: Revert "nova shared storage: rbd is always shared storage" https://review.opendev.org/726863
14:18:03 openstackgerrit Lee Yarwood proposed openstack/nova stable/queens: Revert "nova shared storage: rbd is always shared storage" https://review.opendev.org/726864
14:23:41 sean-k-mooney by the way are we planning to backport https://review.opendev.org/#/c/663365/ upstream
14:24:02 sean-k-mooney its the fix for bug@ #1831723
14:24:18 sean-k-mooney bug: #1831723
14:24:18 openstack bug 1831723 in OpenStack Compute (nova) "The flavor hide_hypervisor_id value can be overridden by the image img_hide_hypervisor_id" [Undecided,In progress] https://launchpad.net/bugs/1831723 - Assigned to Stephen Finucane (stephenfinucane)
14:24:50 sean-k-mooney downstream i think we would want to backport that as im sure customer will hit it at some point
14:25:10 sean-k-mooney but it might be nice to backport upstream too but im not sure its allowed
14:25:24 sean-k-mooney lyarwood: ^ any toughts on the topic
14:26:07 sean-k-mooney we are just adding a namespaced version of an existing unnamsepaced extra_spec
14:26:29 sean-k-mooney downstream that is not conisderd an api change since extra_specs are not part of the api
14:26:35 lyarwood sean-k-mooney: reading
14:27:34 openstackgerrit James Page proposed openstack/nova stable/queens: hardware: fix memory check usage for small/large pages https://review.opendev.org/726867
14:28:58 sean-k-mooney lyarwood: actully that is not the patch i ment to link
14:29:34 lyarwood sean-k-mooney: right you had me slightly confused tbh
14:29:50 sean-k-mooney that one we might also want to backport but one sec
14:29:58 lyarwood yeah that's looks valid to backport
14:30:01 lyarwood that*
14:30:04 sean-k-mooney https://review.opendev.org/#/c/722187/
14:30:08 sean-k-mooney that is the one i ment
14:30:27 sean-k-mooney for https://bugs.launchpad.net/nova/+bug/1841932
14:30:27 openstack Launchpad bug 1841932 in OpenStack Compute (nova) "hide_hypervisor_id extra_specs in nova flavor cannot pass AggregateInstanceExtraSpecsFilter" [Low,In progress] - Assigned to Stephen Finucane (stephenfinucane)
14:33:03 lyarwood sean-k-mooney: so we deprecate hide_hypervisor_id in that change but still provide backward compatability so at first glance I think we can backport this upstream?
14:33:36 sean-k-mooney lyarwood: correct deprecated but still supported
14:33:49 sean-k-mooney we would have to drop the validation changes
14:33:53 sean-k-mooney form the patch
14:34:07 sean-k-mooney but the rest of it i think would be fine
14:34:47 lyarwood ah right that only just landed
14:34:50 openstackgerrit James Page proposed openstack/nova stable/queens: hardware: fix memory check usage for small/large pages https://review.opendev.org/726867
14:34:51 openstackgerrit James Page proposed openstack/nova stable/queens: Fix overcommit for NUMA-based instances https://review.opendev.org/726868
14:35:27 sean-k-mooney lyarwood: yep but that should be fine and easy to call out on the intiall backport patch
14:35:32 sean-k-mooney its pretty self contained
15:01:03 jsuchome dansmith: thanks, I'll address the changes in spec
15:12:29 gibi lyarwood: reported a bug for the image cache issue https://bugs.launchpad.net/nova/+bug/1878024
15:12:29 openstack Launchpad bug 1878024 in OpenStack Compute (nova) "disk usage of the nova image cache is not counted as used disk space" [Undecided,New]
15:12:58 gibi lyarwood: could you please check if it make sense what I wrote there?
15:13:30 gibi dansmith: you worked with the image cache recently so you might be interested ^^
15:13:37 dansmith yeah, reading now
15:13:52 gibi thanks
15:13:57 dansmith if the op has a separate mount for the cache, this wouldn't be a problem
15:14:09 dansmith so it's not going to affect everyone the sae
15:14:10 dansmith *same
15:14:30 gibi yeah, what the downstream customer has is a simple disk partition for the nova instances_path
15:14:41 gibi and the cache is under the instances_path
15:14:43 dansmith right, which I'm sure is common
15:14:57 lyarwood gibi: ack thanks just on calls for a while but will look once I'm off
15:15:04 gibi lyarwood: thanks
15:15:39 dansmith the problem with something like A is that when you're scheduling,
15:15:58 dansmith you don't know whether or not the image is already on the remote system, so you don't know whether to look for hosts with 2*$size disk space or not
15:16:39 gibi dansmith: true
15:16:43 dansmith B doesn't really work either because you can't assume you can purge your way out of the cache limit
15:17:02 dansmith if you boot a hundred instances from different images, you can't prevent the image cache from going over the desired size,
15:17:19 dansmith unless you refuse to boot instances there, which people will complain about because there is plenty of disk space and not understand
15:18:11 gibi could nova-compute periodically update a separate DISK_GB allocation in placement based on the actual size of the image cache
15:18:17 gibi ?
15:18:52 dansmith not periodically, but synchronously with the decision to cache an image (either during boot or otherwise)
15:18:57 dansmith otherwise you have a race
15:20:02 dansmith I'd have to think about that, but we'd need to only do that if the images and cache are on the same filesystem, otherwise we'd count against the wrong total
15:20:13 gibi it will be racey anyhow due to what you said about the problem of requesting allocation for the cache during scheduling
15:21:07 dansmith I mean racing for disk space, which could go badly if you lose, not just racing for image boot
15:21:30 dansmith but yes, the scheduler is never going to know whether or not to pick a host based on cache availability, so you always have that
15:22:24 dansmith we could go totally crazy and create an allocation for each image, by image uuid and after selecting a host, the scheduler could check to see if there was an allocation for that image against the host's provider to decide if it thinks it will fit :)
15:22:43 dansmith that has some nice benefits, but it's a little crazy and there's still plenty of room for racing of course,
15:23:03 dansmith and plenty of room for exhausting all the candidates in a small query set, leading to non-ideal looping of retries
15:23:39 dansmith plus we'd have to have a separate provider for the cache disk if they're separate
15:27:07 gibi complicated indeed
15:27:41 gibi I will pass the workaround of having the cache on a different partition to downstream
15:27:56 gibi at least that is something that the downstream project can do
15:28:24 aarents gibi: dansmith we have this issue, painfull one
15:28:48 dansmith gibi: ack
15:29:02 aarents gibi yep in some case we put cahe in another file system to get ride of this
15:29:22 gibi dansmith: the old DiskFilter had the disk_available_least info to prevent overallocation but we removed the DiskFilter
15:30:27 dansmith yeah, fair point
15:30:56 gibi we might want to re-introduce something like diks_available_least as a filter? or a pre-filter with placement support?
15:31:40 dansmith I think diskfilter had plenty of other problems, like the other way where the filter behavior conflicted with the hypervisors listing, which definitely causes support cases

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