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#openstack-nova - 2018-03-14
16:11:54 arvindn05 mriedem: thanks!
16:11:57 dansmith stephenfin: edleafe: but changing dashes to spaces doesn't change the unique elements of the uuid, it only changes the uniqueness of the string as a SQL hack
16:12:10 bauzas stephenfin: I was walking over the RequestSpec tablre
16:12:21 dansmith using the null uuid is a completely legit way to do this, as bauzas did for reqspec
16:12:34 dansmith but it doesn't help as much in this case because of where the constraints lie
16:13:44 cfriesen bauzas: I understand the current extra specs, just wasn't sure what it would look like with the placement stuff added to it.
16:14:11 openstackgerrit Chris Dent proposed openstack/nova-specs master: Spec for isolating configuration of placement database https://review.openstack.org/552927
16:15:03 bauzas dansmith: yeah, I'm trying to load again the instance mapping context in mind
16:15:29 bauzas and why it has to be different from my walkthrough over reqspec
16:15:32 dansmith bauzas: instance mapping is storing the uuids of the instances, so it can't store a duplicate one since there is a unique constraint on that column
16:16:07 dansmith there's no room inside it to stash the uuid elsewhere and use the null uuid as the marker key
16:16:29 bauzas disclaimer: I have goblins at home that make noise, I need to take my Bose headset
16:20:16 bauzas dansmith: mmmm, I was just considering the Nul UUID for storing the last RequestSpec record I was walking thru
16:20:42 bauzas now, I'm looking at instance_mappings
16:22:37 dansmith bauzas: you were storing the instance uuid inside a blob field, which was not required to be unique (nor would be) and thus it didn't conflict with the actual reqspec for the instance
16:22:47 dansmith bauzas: and using the nil uuid to find the marker each time
16:22:58 bauzas yeah, also because I was wrong 5 mins ago
16:23:12 dansmith in instance mapping, we can't store the instance's uuid exactly again because it's a UC field
16:23:21 bauzas I wasn't walking over reqspec, but rather over the instances table
16:23:27 bauzas right
16:24:04 bauzas dansmith: I wasn't storing the instance field, I was storing the request spec of the last instance I checkedc
16:24:12 dansmith right
16:24:40 bauzas now, I'm looking at the instance mappings migration script
16:24:59 dansmith we could have used the nil uuid here and then stashed the instance's real uuid in the project field or something like that, but that would be rather nasty as well and could have affected runtime in other ways
16:25:04 dansmith and, this is done and in people's systems
16:26:00 bauzas right
16:26:07 bauzas now the thing is done
16:26:35 cdent edleafe: is member_of is a state of ready for review?
16:26:39 cdent s/is/in/
16:28:12 bauzas gibi: so, I just saw https://github.com/openstack/oslo.versionedobjects/commit/0e3526710f67b3b4ebab60864ea060fa9caf9537
16:28:46 bauzas gibi: like I said earlier, I bet that valid UUIDs with spaces instead of hypens are valid per-RFC
16:28:54 bauzas hyphens
16:29:26 mriedem i believe the gibster is currently celebrating the national holiday of the rubik's cube
16:29:42 edleafe cdent: yep
16:29:43 dansmith ugh
16:29:51 melwitt dansmith, mriedem, tssurya: I could use your eyeballs on this cells session recap to add/correct anything I might have missed before I send it to the dev ML https://etherpad.openstack.org/p/nova-ptg-rocky-cells-summary
16:29:54 dansmith bauzas: that's really unfortunate
16:30:11 cdent thanks edleafe
16:30:53 bauzas dansmith: I need some tests on my box
16:31:05 bauzas dansmith: but I think o.vo badly coerces, that's it
16:31:16 dansmith bauzas: hmm?
16:31:35 dansmith bauzas: it should only be emitting a warning (now error) if the format doesn't match
16:31:49 dansmith bauzas: making it required formatting would be breaking our RPC API
16:32:35 bauzas dansmith: I'm just saying that '52ec5cae 1654 42ad bc38 ebab73fbb161' is a valid UUID
16:32:46 bauzas dansmith: so o.vo shouldn't complain at all
16:32:58 dansmith bauzas: ah, about that I seee
16:33:15 dansmith bauzas: well, I was against enforcing any one of the many ways to write a uuid in the first place
16:33:19 dansmith the warning was the compromise
16:33:33 dansmith melwitt: looks okay to me
16:33:53 melwitt cool, thanks
16:33:56 bauzas dansmith: right, I remember the early and shiny days of nova/objects/fields.py and the UUID() field type :)
16:34:03 dansmith yeah
16:34:35 tssurya melwitt: did a small change, otherwise looks good to me
16:35:34 melwitt sweet, thanks
16:36:14 bauzas dansmith: stephenfin: gibi: so I'm wrapping my head around http://paste.openstack.org/show/700970/
16:36:28 bauzas because this is wrong
16:36:47 dansmith it's opinionated
16:37:00 stephenfin bauzas: I think the RFC is wrong
16:37:01 stephenfin :)
16:37:38 bauzas it says 16 octets, period.
16:37:43 dansmith bauzas: note it allows removing the dashes :)
16:37:44 dansmith bauzas: because it thinks that's okay :)
16:37:49 dansmith which we could also have done
16:39:33 bauzas we could have done many things
16:39:34 stephenfin bauzas: It didn't matter much before anyway since we were undoing it. This will only start to bite us if/when o.vo decides to make that warning an error https://github.com/openstack/nova/blob/fd59fbd4d1914d2adf35a85435ba4aa433f082cd/nova/cmd/manage.py#L1171
16:40:06 bauzas but I'm trying to see how we could better coerce in o.vo so that would make both not changing the DB, and make edleafe and stephenfin happy
16:40:19 edleafe bauzas: I really don't care
16:40:29 dansmith stephenfin: that would (a) be a change to our (and others') RPC APIs, but also (b) we could easily handle this in _from_db_obj(), or by doing the migration process with the low-level routines instead of objects
16:40:33 edleafe I was just trying to fix a potential issue
16:40:37 bauzas \o/
16:40:55 bauzas I'm litterally 20 mins away from a long holiday period
16:41:07 edleafe but spaces in a UUID are not valid. Removing the dashes is fine
16:41:07 bauzas would those 20 mins well spent in fixing that then ?
16:41:26 bauzas c'on
16:41:32 bauzas it's a *string*
16:41:34 dansmith a UUID is a number
16:41:42 dansmith the string representation of it can be many things
16:41:49 dansmith microsoft encloses them in {} to make them stand out
16:41:55 bauzas how the string translates to an hex is something fine even with spaces
16:42:07 bauzas yeah
16:42:48 edleafe hey, I wanted to store all uuids are 128-bit integers, but got out-voted by the human-readable people
16:42:56 edleafe s/are/as
16:43:17 bauzas edleafe: it's comprehensive
16:43:32 bauzas edleafe: but the o.vo coercing method shouldn't care at all about the formatting
16:44:04 bauzas it should just assume Good Faith (c)
16:46:45 cfriesen on a totally different topic...does nova wait to ensure vifs are actually plugged when doing a live migration? I see it calling self.virtapi.wait_for_instance_event() on instance spawn and cold migration, but not for live. I assume the flow is somewhat different?
16:47:22 stephenfin bauzas: Before you go, fancy pushing these two patches through? https://review.openstack.org/#/c/385071
16:47:39 stephenfin Additional shuffling things around/adding docstring patches
16:47:48 bauzas my review stats are poor this week
16:47:57 bauzas thanks to the NUMA spec
16:48:18 bauzas (and the f*** tax-credit document I had to write)
16:48:38 stephenfin bauzas: No better time, in that case
16:48:53 bauzas https://docs.python.org/2/library/uuid.html#uuid.UUID "When a string of hex digits is given, curly braces, hyphens, and a URN prefix are all optional.'
16:49:13 bauzas so, yeah, really the space carries a lot more, but meh
16:49:26 dansmith tssurya: ah, yeah, kudos for spotting it in the initial patch :)
16:50:17 bauzas dansmith: planning to do a Cells meeting in 10 mins ?
16:50:21 dansmith yar
16:50:29 bauzas cool, I can attend it for once \o/
16:50:41 dansmith bauzas: I thought you were leaving in 20 minutes? :)
16:51:09 bauzas for the first time since 6 months I can attend a cells meeting, I won't skip it

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