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#openstack-nova - 2023-02-21
16:37:56 bauzas the fact is, I wrote Opinion
16:38:04 bauzas unless people have concerns with what I wrote, I'm done.
16:39:07 bauzas looks not
16:39:11 bauzas then I assume we're done.
16:40:16 dansmith ++
16:40:18 bauzas thanks all
16:40:23 bauzas #endmeeting
16:40:23 opendevmeet Meeting ended Tue Feb 21 16:40:23 2023 UTC. Information about MeetBot at http://wiki.debian.org/MeetBot . (v 0.1.4)
16:40:23 opendevmeet Minutes: https://meetings.opendev.org/meetings/nova/2023/nova.2023-02-21-16.00.html
16:40:23 opendevmeet Minutes (text): https://meetings.opendev.org/meetings/nova/2023/nova.2023-02-21-16.00.txt
16:40:23 opendevmeet Log: https://meetings.opendev.org/meetings/nova/2023/nova.2023-02-21-16.00.log.html
16:40:33 elodilles thanks o/
16:40:57 dansmith bauzas: so, gmann and I were running that memory usage patch in periodic on tempest jobs for a few days to make sure it didn't substantially worsen things
16:41:07 dansmith and my survey at the moment indicates that it looks good
16:41:41 dansmith so I'll propose to make it enabled for ceph-multistore (which will also impact glance) and we'll see if gmann is cool with that when he's around
16:41:44 bauzas nice to hear
16:41:52 bauzas ack, do it and I'll vote
16:45:08 opendevreview Dan Smith proposed openstack/nova master: Use mysql memory reduction flags for ceph job https://review.opendev.org/c/openstack/nova/+/874664
16:45:11 dansmith bauzas: ^
17:43:02 bauzas dansmith: I doubt that cells_v2 map_instances could work with https://bugs.launchpad.net/nova/+bug/2007922 (even I asked for it)
17:43:19 bauzas dansmith: tl;dr: the instance mapping exists but the cell value is None
17:43:30 bauzas and we know the instance is in cell0 DB
17:43:53 dansmith yeah, as I said, I initially missed that the person said they had reference in the mappings table
17:43:56 bauzas dansmith: I guess the simpliest thing is to hack the DB to add the cell0 uuid in the instancemapping record, nope ?
17:44:08 dansmith probably
17:44:14 bauzas or do we have a better nova-manage command ?
17:44:18 bauzas looking at the docs, nope
17:44:29 dansmith not that I know of
17:44:33 bauzas this instance is somehow sit in the middle
17:44:46 bauzas not fully migrated but in between
17:44:58 dansmith not fully ... mapped?
17:45:06 bauzas sorry, yeah mapped
17:45:23 bauzas I'll propose the ALTER to the reporter
17:47:42 dansmith don't we have a mapped flag on the instance (or something else)?
17:48:36 bauzas in the instances table you mean ?
17:48:57 dansmith I thought it was.. that's how we survey instances that need to be mapped right?
17:49:13 dansmith just wondering if that flag matches or not
17:52:44 bauzas so
17:52:55 bauzas https://github.com/openstack/nova/blob/master/nova/cmd/manage.py#L874
17:53:12 bauzas we just iterate over a limit and a marker on the instances table from a cell that's given
17:54:34 dansmith ah right
17:54:44 bauzas and I think I understand how the cell ID was set to None
17:54:51 bauzas https://github.com/openstack/nova/blob/439c67254859485011e7fd2859051464e570d78b/nova/objects/instance_mapping.py#L73
17:55:31 dansmith it only does that if it's not none though
17:55:34 bauzas anyway, map_instances *could* work with cell0
17:56:18 bauzas if the reporter runs map_instances with cell0 attribute, it will loop over the contents of cell0's instances table and will create an instancemapping object
17:56:42 bauzas oh wait, fuck no
17:56:42 bauzas https://github.com/openstack/nova/blob/master/nova/cmd/manage.py#L791-L792
17:56:57 bauzas so, definitely the easier is to alter the db
18:00:12 dansmith again, I only thought it was useful to run map if the mapping didn't exist
18:03:45 bauzas yup
18:03:54 bauzas or the reporter could then delete the instance mapping
18:10:15 sean-k-mooney bauzas: elodilles can we prioritise review of this if possibel https://review.opendev.org/c/openstack/nova/+/874547
18:10:30 opendevreview Takashi Natsume proposed openstack/placement master: Move implemented specs for Xena and Yoga release https://review.opendev.org/c/openstack/placement/+/853730
18:11:18 sean-k-mooney this will help us fix our downstream ci
18:13:16 bauzas done but I leave you +W as I don't have a lot of context
18:15:39 sean-k-mooney tl;dr we use bindep in our downstream jobs to install deps before runing tox but rhel 8 nolonger has python-devel
18:15:47 gmann dansmith: +W on 'mysql memory reduction flags for ceph job'
18:15:55 sean-k-mooney i wanted to check with elodilles to make sure they were ok with the stable-only change
18:16:00 dansmith gmann: cool
18:16:04 dansmith thanks
18:24:10 dansmith gmann: oh jeez, I didn't realize the mysql periodic thing hadn't landed yet
18:24:32 dansmith gmann: do you think we should wait for that to soak for a bit?
18:24:47 dansmith I know the devstack one did, and I guess I misread that the tempest one hadn't yet
18:26:05 gmann dansmith: I also did not realize it when I checked that patch. but I think it is ok to enable it in ceph job and see.
18:26:25 gmann we can always revert it if it fail and make delay things during release time
18:26:34 dansmith okay, that's my preference too
18:44:46 mnaser i got a fun one. it looks like by default nova saves the az of the vm in the cell db, but it doesn't update the request_spec, but when we do migrations, we pass the request_spec to the scheduler (which contains az=null) which then moves you from one az to another in the migration
18:45:05 mnaser since .. https://github.com/openstack/nova/blob/90e2a5e50fbf08e62a1aedd5e176845ee22d96c9/nova/scheduler/request_filter.py#L138-L166 checks for request_spec az
18:45:40 sean-k-mooney mnaser: this was changed recently
18:45:56 mnaser this is in a scenario where an operator wants to make vms stick to their az if a user doesnt specify one
18:46:22 sean-k-mooney right so we spent a lot fo time trying to decide what the sematics shoudl be
18:46:56 sean-k-mooney im trying to find the spec
18:47:32 sean-k-mooney https://specs.openstack.org/openstack/nova-specs/specs/zed/implemented/unshelve-to-host.html
18:47:38 sean-k-mooney i guess this was for unshleve
18:48:05 sean-k-mooney mnaser: we epect tht the request spec would not have the az by the way if the user did not request one
18:48:44 mnaser makes sense cause that's their request
18:49:12 mnaser i understand it might not be everyone that wants this, but maybe for live migration use case it can cause issues if nova ends up doing cross-az migrations
18:49:54 sean-k-mooney for move operations where we supprot specifying a AZ it would be ok in some cases to set it in the request spec
18:50:13 sean-k-mooney mnaser: but we would want to have the same beahivor as in the unselve spec
18:50:29 sean-k-mooney i dont recal if we fixed the other move operatiosn to be consitent with that when we did this
18:50:35 sean-k-mooney Uggla: do you recall
18:51:36 sean-k-mooney mnaser: wiht unshelve to a specific az if you set it in the unshelve request and it was not set in the orgainl request spec it will be set after
18:52:52 sean-k-mooney mnaser: live migraiton does not currently supprot an az
18:52:55 mnaser sean-k-mooney: esentailly im thinking this is where this can be changed https://github.com/openstack/nova/blob/f01a90ccb85ab254236f84009cd432d03ce12ebb/nova/compute/api.py#L5499-L5500
18:53:20 mnaser cause live migrating from one az to another could pretty much fail, and we can just have it as an option i guess if we dont want to change default behaviour
18:53:22 sean-k-mooney nor does migrate
18:53:35 mnaser in most worlds migrate or live migrate will fail across az's
18:53:40 mnaser esp if you're using different storage backends for example
18:53:43 sean-k-mooney mnaser: this would be an api change and need a spec
18:54:21 sean-k-mooney in general live migration betwen AZ will either work on not work depending on yoru deployment. in general i would expect it to work in most cases
18:55:17 sean-k-mooney it just comes down to if you have exchanged ssh keys such that the hyperviors can comunicate and if you are using az with cinder or not
18:55:25 sean-k-mooney and cross_az attach
18:56:00 mnaser Maybe we can make it so that if cross az attach = false then it would update the request spec to match?
18:56:07 sean-k-mooney no
18:56:15 sean-k-mooney no config drvent api behavior
18:56:20 sean-k-mooney this is not a bug
18:56:38 sean-k-mooney if we want to supprot move operation to target an AZ or change the request spec this is an api change
18:56:54 mnaser No it’s not to target an AZ
18:56:54 mnaser No it’s not to target an AZ

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