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#openstack-nova - 2024-02-14
10:18:56 Uggla bauzas, thx
10:26:38 opendevreview Amit Uniyal proposed openstack/nova master: Separate OSError with ValueError https://review.opendev.org/c/openstack/nova/+/908825
10:26:38 opendevreview Amit Uniyal proposed openstack/nova master: Added context manager for instance lock https://review.opendev.org/c/openstack/nova/+/873648
10:26:39 opendevreview Amit Uniyal proposed openstack/nova master: Removed explicit call to delete attachment https://review.opendev.org/c/openstack/nova/+/891289
10:26:39 opendevreview Amit Uniyal proposed openstack/nova master: Disconnecting volume from the compute host https://review.opendev.org/c/openstack/nova/+/877446
12:50:10 stephenfin Uggla: Are you happy with https://review.opendev.org/c/openstack/openstacksdk/+/893505 now? Sounds like you figured out the issues you were having using SDK for Manila so that doc is probably correct?
12:59:01 Uggla stephenfin, tbh not really I did not manage to use the service token. So for the moment I left it behind.
12:59:15 stephenfin ah, okay
13:11:24 ganso gibi, dansmith, sean-k-mooney: hi! could you please review this small patch when you have a few minutes? thanks in advance! https://review.opendev.org/c/openstack/nova/+/906053
13:12:29 sean-k-mooney ganso: its currenlty in merge conflict so it needs a rebase
13:13:29 ganso sean-k-mooney: it is? I thought it was predicting a merge conflict with other unmerged patches. Let me rebase it and fix the conflits then, just a sec
13:14:01 sean-k-mooney ganso: no when it says merge conflcit on the left like that its not mergable with master
13:14:50 sean-k-mooney this is really a feature by the way but ill try and load some context
13:15:48 ganso sean-k-mooney: oh I was looking at a stale page. I had to ctrl+F5 for it to show up
13:15:59 ganso sean-k-mooney: a feature? you mean it wouldn't be backportable?
13:19:02 opendevreview Rodrigo Barbieri proposed openstack/nova master: Use dedicated live migration network during pre-migration https://review.opendev.org/c/openstack/nova/+/906053
13:25:57 sean-k-mooney ganso: without new config option i dont think it is backportable no
13:26:13 sean-k-mooney ganso: any change in what network are used could break an existing deployment
13:26:35 sean-k-mooney ganso: im on a call by the way so i have only skimed the patch so perhaps that not a concern
13:26:54 sean-k-mooney we ahve a new related feature
13:27:10 sean-k-mooney which allows configuing what network we use for cold migration
13:27:26 sean-k-mooney which is i belive the same code that is deictating what network we are usign itn pre-migration
13:28:17 ganso sean-k-mooney: I understand the concern. I have a customer that is running into this issue. They have 2 networks, one for controller and one for migration. The bug causes the controller network to be used and the patch actually addresses the use of the correct migration network. It doesn't change their setup.
13:28:37 sean-k-mooney we added https://docs.openstack.org/nova/latest/configuration/config.html#libvirt.migration_inbound_addr
13:29:15 ganso sean-k-mooney: yep, that is the setting my customer is using to determine the migration network. The issue is that the setting is being ignored by the pre-live-migration step
13:29:39 sean-k-mooney ganso: migration_inbound_addr is somethign we are adding this cycle
13:29:57 sean-k-mooney so unless they are using master they are suign live_migration_inbound_addr
13:30:01 ganso sean-k-mooney: hmmmmmm let me confirm the naming, maybe it is similar to the other one I'm referring to
13:30:02 sean-k-mooney which is currently only for the libvirt part
13:31:00 sean-k-mooney yep
13:31:00 ganso sean-k-mooney: so the pre-live-migration code is using the wrong address, derived from the same way cold migration determine its address
13:31:00 sean-k-mooney right so for cold migration there was no way to use a diffent netwrok before now
13:31:00 ganso sean-k-mooney: yes they are using libvirt
13:31:00 ganso sean-k-mooney: yes! live_migration_inbound_addr
13:31:20 sean-k-mooney so on master you could "fix this" by settin gboth option to use the migration network
13:31:48 sean-k-mooney for older release it may be valid to change but it not valid to make cold migratoin use the live migration network
13:32:07 sean-k-mooney based on only live_migration_inbound_addr
13:32:14 ganso sean-k-mooney: I am not familiar with the patch code, I just found the fix proposal that I need, but I am a bit surprised that the fix needs an object versioning bump to make it use the correct network config instead of the wrong one
13:32:45 ganso sean-k-mooney: certainly, wouldn't make sense the change the cold-migration behavior, that indeed would be a new feature
13:32:48 sean-k-mooney so its not clear its using the wrong netwrok
13:33:02 sean-k-mooney techncially the exisitng option is only for the libvirt traffic
13:33:25 ganso sean-k-mooney: but fixing something that is a broken behavior in a previously accepted feature is kinda not really a new feature IMO
13:33:45 sean-k-mooney ganso: based on the docs for live_migration_inbound_addr
13:33:47 sean-k-mooney tis not broken
13:33:57 sean-k-mooney there expecation is incorrect based on teh docuemtned behavior
13:34:07 sean-k-mooney ganso: im not saying what you ask for is not an imporvement
13:34:24 sean-k-mooney im just sayting that is not what the docs say the config option does
13:34:34 sean-k-mooney """This option indicates the IP address which should be used as the target for live migration traffic when migrating to this hypervisor. This metadata is then used by the source of the live migration traffic to construct a migration URI."""
13:34:46 sean-k-mooney copying the disk for block migration is not part of the live migration traffic
13:35:00 ganso well, pre-live-migration is part of live-migration, and if live-migration is not using live-migraiton-inbound-addr then it is somewhat diverging from expected behavior
13:35:08 ganso sean-k-mooney: oh copying the disk is not part of live migration traffic
13:35:20 ganso sean-k-mooney: I see, the devil is in the details xD
13:35:32 sean-k-mooney right this option is litrrally jsut for the data copied by libvirt
13:35:47 sean-k-mooney not the addtional actoins taken by nova
13:36:13 sean-k-mooney but i agree the enhacment that you are asking for makes sense btu that is why its kind of a feature not a bug
13:37:09 ganso sean-k-mooney: yea I understand the reasoning now. The fact that it changes the object versioning already makes it non-backportable If I understand correctly, so the fix would need to be coded differently to be backportable anyway
13:37:35 sean-k-mooney yes
13:38:57 ganso I need to analyze the code to see if that would be possible, but then also whether it would be acceptable as an backportable enhancement to an existing feature (pending more discussion)
13:39:00 sean-k-mooney ganso: so the new feature we added https://github.com/openstack/nova/commit/6bca37e904e9e56b250b123abde1901e951c8c9a
13:39:02 ganso I will talk to my customer first
13:39:05 sean-k-mooney i think would solve this usecase
13:39:20 sean-k-mooney and that is coded in a way that is backportable
13:39:31 sean-k-mooney so we coudl disucss if we wanted to backport this upstream to adress that bug
13:39:39 sean-k-mooney gibi: ^
13:40:29 ganso sean-k-mooney: it is? but it is introducing a new config option (and it is indeed a new feature) so I assumed even if the code is backportable, it wouldn't be accepted to be
13:40:30 sean-k-mooney do you think https://bugs.launchpad.net/nova/+bug/1939869 is a vaild reason to backport the new migration_inboud_address config option
13:41:24 sean-k-mooney ganso: we normally would not backport it unless there is a large pain point that affects operators
13:42:10 sean-k-mooney we do sometime back port new config options the impoarnt thing with a backport of this kind is it must not change behaivor by default
13:42:57 sean-k-mooney which is true in this case if you want to move all traffic to the migratoin network with that feature you have to set the config option to use the dedicated networks ip/fqdn/hostname
13:43:10 ganso sean-k-mooney: if the default value of the new config options retains the existing behavior, that is less concerning impact for existing deployments while backporting
13:43:36 sean-k-mooney yep it does which is and we also did that for upgrades
13:43:50 sean-k-mooney we did not want to change the behavior on upgade for the same config file
13:44:33 sean-k-mooney elodilles: ^ i know this is borderline but i think gibis feature is a more reasoable approch then https://review.opendev.org/c/openstack/nova/+/906053
13:45:15 ganso sean-k-mooney: yea if it solves the issue I am happy with backporting that instead. I need to test to be 100% sure, but it probably does as you say
13:45:52 ganso that other patch may even not be that much necessary anymore
13:46:09 sean-k-mooney ganso: i bleivle https://github.com/openstack/nova/commit/6bca37e904e9e56b250b123abde1901e951c8c9a#diff-486ddc37ce8e7c105a51566dd2cffbda034f28fae7eaad2e74abf470ab296352L4514 is the important part
13:47:27 sean-k-mooney i belive get_host_ip_addr is the common fucntion that is causing hte current behavior so yes https://review.opendev.org/c/openstack/nova/+/906053 shoudl not be requried anymore
13:49:04 ganso yep
14:55:38 opendevreview Rodrigo Barbieri proposed openstack/nova stable/2023.2: [libvirt]Add migration_inbound_addr https://review.opendev.org/c/openstack/nova/+/908995
14:56:27 ganso sean-k-mooney: I proposed the backport just to get the discussion started ^. Waiting to hear gibi's thoughts on this
14:56:42 sean-k-mooney ack
15:02:19 dougszu Thanks for looking at https://review.opendev.org/c/openstack/nova/+/906053. It comes from a time before the other patch. I will take a look at it shortly.
15:02:50 elodilles sean-k-mooney: well, if it's more like a feature than a bugfix, then best to avoid the backport, though, there can be exceptions, i mean, if the stable cores agrees that it worth the risk and most probably won't cause any regression, then it can be backported. (the only thing is NOT to change the current behaviour for existing deployments, i'd say)
15:03:41 sean-k-mooney elodilles: ya for upgrade reasons when we added this it preserved the existing behavior
15:04:07 sean-k-mooney elodilles: so if we were to backport it as with master you would have to modify the config option to use it
15:04:14 elodilles +1
15:04:35 sean-k-mooney elodilles: tl;dr we supprot movign the libvirt traffic to a dedicate network but only for live migraton
15:04:43 sean-k-mooney the feature enables that for cold migration
15:05:15 sean-k-mooney and as a sideffect also move the block copy done by nova wich is common for live migration to the new network if you opt in with the config option
15:05:45 sean-k-mooney not all users were aware that the live_migration_inbound_adr is just for the libvirt traffic
15:05:54 sean-k-mooney not also for novas data transfers
15:06:52 sean-k-mooney https://bugs.launchpad.net/nova/+bug/1939869 is partly a misundertaing of how thing work but i dont think its an unresobale expectation and other operator may have fallen faul of that too
15:08:34 elodilles i see, thanks for the details
15:19:51 elodilles sean-k-mooney: added my (long) comment to the backport o:)
15:21:52 sean-k-mooney ack we proably should chat about this either in the channel or in the team meetign to get import form stable folks in general
15:22:02 elodilles +1
15:30:07 opendevreview Merged openstack/nova master: HyperV: Add todo to remove HyperVLiveMigrateData object https://review.opendev.org/c/openstack/nova/+/906636
16:01:57 dougszu sean-k-mooney: Perhaps I missed something, but for https://bugs.launchpad.net/nova/+bug/1939869, i'm not sure how https://review.opendev.org/c/openstack/nova/+/908995 is going to 'fix' it. Since the source HV is calling the target HV by RPC, which then needs to get the IP of the source HV (not the hostname)
16:04:58 sean-k-mooney dougszu: it wont because it should not
16:05:20 sean-k-mooney howeve if you set the other config option then those calls shoudl use that for the data transfer

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