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#openstack-nova - 2018-06-08
15:28:59 mgagne so my bad, just a matter of paying more attention to belmiro's talk =)
15:29:26 mriedem 345 must be the migration that fails?
15:29:49 mriedem yeah....
15:30:03 mgagne yes
15:30:36 mriedem 345 should probably have a CONF.cells.enable condition
15:30:40 mgagne he had a slide about those migrations
15:30:50 mgagne mriedem: was thinking the same ++
15:31:10 mriedem but if we did that, you might not migrate your flavors to the api db and then you have other problems, i think?
15:31:24 mriedem we could log a warning, but likely no one would notice if db sync didn't fail
15:31:30 mgagne yea, that's what I'm trying to figure out
15:31:32 mriedem nova-status upgrade check would be good here
15:31:36 dansmith mriedem: yeah and looking at conf in migrations got people into trouble before, so...
15:31:58 mriedem if cells v1 and no flavors in api db, fail (nova-status check)
15:32:22 mriedem at the very least, we need something in the 'upgrade from cells v1' docs
15:32:38 mriedem https://docs.openstack.org/nova/latest/user/cells.html#upgrade-with-cells-v1
15:33:34 mgagne mriedem: I think the special case that isn't documented yet is: if you wish to upgrade but wish to keep cellsv1 for reasons. what to do.
15:34:00 mgagne but I think it would create more confusion if it was in the "main" documentation.
15:39:34 mriedem we havea cells faqs section...
15:39:55 mriedem "DB migration 345 fails saying I haven't migrated all flavors to the API DB but I'm using cells v1 still..."
15:40:06 mriedem https://docs.openstack.org/nova/latest/user/cells.html#faqs
15:50:59 mriedem mgagne: i guess let us know what you think would be most helpful for documenting this once you get past it - we could also put a comment in the db migration itself in case people are hitting it and then go there to see what's going on
15:52:35 mgagne nice :D
15:53:16 mgagne I managed to create a lightweight setup to test the migration so I can iterate faster. shouldn't be long before I get some interesting results
15:54:53 melwitt mriedem: are you okay with a minor release bump on this based on the last comment? sounds like it might be more intuitive to people https://review.openstack.org/573454
15:57:10 mriedem s/people/doug/
15:57:18 mriedem i'm a big meh
15:57:30 mriedem if we do a minor release for every os-traits updates, we'll just have a ton of minor updates
15:57:41 mriedem s/updates/release/ on that first one
15:57:49 melwitt yeah
16:00:37 melwitt initially I had done a minor version bump locally before I saw that a past release did a patch bump. but I think the release prior to that one was a minor bump. it's been inconsistent
16:02:36 openstackgerrit Balazs Gibizer proposed openstack/nova master: Fix unbound local when saving an unchanged RequestSpec https://review.openstack.org/573768
16:04:29 cfriesen arguably a new trait is a new "feature", which would make it a minor update if you follow semver. but so much of openstack doesn't anyways...
16:06:44 melwitt I shall change it to a minor bump
16:17:01 cfriesen mriedem: thanks for starting that OSC etherpad. you mentioned that aborting an in-progress migration doesn't really fit on the server resource. From a user perspective it seems to me that "openstack server migration list" and "openstack server migration abort" would be sensible commands
16:46:04 openstackgerrit Chris Dent proposed openstack/nova master: Optional separate database for placement API https://review.openstack.org/362766
16:46:05 openstackgerrit Chris Dent proposed openstack/nova master: Isolate placement database config https://review.openstack.org/541435
16:46:06 openstackgerrit Chris Dent proposed openstack/nova master: Ensure that os-traits sync is attempted only at start of process https://review.openstack.org/553857
17:02:28 openstackgerrit Chris Dent proposed openstack/nova master: Add PLACEMENT_DB_ENABLED=True to the nova-next job https://review.openstack.org/564067
17:02:42 jmlowe cdent: You've got some migration path for getting existing placement db's out of nova_api db?
17:04:28 cdent jmlowe: we discussed that at summit (see https://etherpad.openstack.org/p/YVR-placement-extraction ) and the general consensus in the room was allowing people to do it manually according to whatever worked for them (there are a variety of options on the etherpad)
17:05:09 jmlowe ok, I was probably harassing Jeremy at the time and missed it during that session
17:07:36 jmlowe I'm probably good with stop, dump, restore to new db, start, make schemas diverge
17:08:31 cdent jmlowe: if you feel inclined to add that "I'm good with" to the etherpad, that would be a good datapoint
17:09:48 jmlowe done
17:12:24 cdent thanks
17:41:39 openstackgerrit Jan Gutter proposed openstack/os-vif master: [WIP] Add support for generic offload representors https://review.openstack.org/572081
18:21:24 mgagne mriedem: with newton, if flavors are fully converted to object, wouldn't it mean that all code path use the API database to read the information since it goes through object? If running CellsV1, how could it still read from local cell database? Isn't the code reading from local gone in newton? But I found lot of notes by alaski telling models in non-api database is deprecated since they got moved to API database. So I'm a bit confused.
18:22:42 mriedem i believe the flavor object looks for the flavor in the api db and if not there, falls back to the cell db
18:22:44 mgagne I'm trying to see if I just need to skip the migration and still continue creating flavor in compute cell OR if I can delete them since they got all moved to API database and everything should be reading from it.
18:23:17 mriedem https://github.com/openstack/nova/blob/stable/ocata/nova/objects/flavor.py#L403
18:23:32 mriedem that checks the api first then falls back to the cell db
18:23:33 mgagne yes, that place.
18:23:38 mriedem in ocata at least
18:23:45 mriedem i know we dropped that compat code....
18:24:01 mriedem gone in queens https://github.com/openstack/nova/blob/stable/queens/nova/objects/flavor.py#L377
18:24:45 mgagne but lets say I query an instance and join to flavor. Would the join use the flavor object or would db.api load the data first and use Flavor object later?
18:25:32 mriedem the instance.flavor is not in the flavors table,
18:25:33 mgagne because it wouldn't make much sense to join instance to flavor cross databases right? I'm not familiar with that part tbh.
18:25:36 mriedem it's in the instance_extras table
18:25:42 dansmith mgagne: the instance has the flavor stashed with it in the cell db now
18:25:43 dansmith yeah that
18:25:48 mriedem the instance.flavor is stored separately keyed per the the instance
18:25:50 mgagne oh, you get a copy of the flavor right
18:25:51 mriedem in case the flavor is deleted
18:25:51 dansmith so you only need it in the api db for build and list
18:27:08 mgagne so this would mean I could delete content of instance_types in compute cell db just like the original migration tried to do.
18:27:32 mriedem yeah, the api isn't going to read flavors out of the cell dbs
18:27:43 mgagne awesome news then
18:27:45 dansmith probably should to make sure nothing falls back to that when it shouldn't, since it'll go away
18:28:00 mgagne yes, that's my main concern
18:28:38 mgagne so if I skip flavor migration in cell, does it mean entries are now orphan and can be deleted (and not migrated). I guess that's my question.
18:28:49 mgagne I suppose I can test a bit.
18:28:54 mriedem i believe so
18:30:02 mriedem when migrating flavors from child cells to the api db, it handles duplicates (per the flavorid) so should be fine https://github.com/openstack/nova/blob/stable/ocata/nova/objects/flavor.py#L755
18:30:15 dansmith mgagne: if they're all the same then yeah
18:30:23 dansmith mgagne: which I think they have to be right?
18:30:23 mgagne yes, they are the same.
18:30:25 mriedem as in you could have m1.tiny in 4 cells but with different primary key ids, but the online data migration wouldn't carry over the primary key id, just create a new flavor in the api db
18:30:49 mriedem right, for each flavor in cell db, create in api db, ignore duplicates
18:30:50 mgagne mriedem: afaik, you can't have different primary key id =)
18:31:02 dansmith yeah,
18:31:07 mriedem well, i mean you could have m1.tiny in different cells with the same id=1
18:31:11 dansmith because it's referenced directly by the instance by id
18:31:14 mriedem but you can only have one m1.tiny in the api db
18:31:14 dansmith mriedem: I don't hink so
18:31:20 mgagne lot of gotcha in cellsv1 that assumes primary key is the same everywhere
18:31:27 mriedem oh, well that i didn't know
18:31:34 dansmith mriedem: in old school nova, instance.instance_type_id refers to flavor.id
18:31:35 mriedem all the more reason to get off cells v1 :)
18:31:39 dansmith so they have to be identical AFAIK
18:31:40 mgagne I got bitten in the past...
18:31:59 dansmith are we comparing scars now?
18:32:03 mgagne hehehe
18:32:08 dansmith :)
18:32:11 mriedem so i guess the 354 data migration blocker isn't so bad for you
18:32:20 mriedem you just needed to run the online data migratoin on each cell db
18:32:22 mgagne I'm sure yours are more numerous than mines
18:33:00 mgagne alright, will go back to my ffu dungeon then :D
18:34:27 mriedem say hi to lyaaaaaaaarwood for me
18:35:40 mgagne is it a friend or some beast I should find and fight in the dungeon? :D

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