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#openstack-nova - 2019-04-09
17:11:17 dansmith bauzas: um, really?
17:11:38 dansmith bauzas: you want cern to have to migrate all their workloads before/during an upgrade?
17:11:49 bauzas dansmith: no, that's not what I meant
17:12:05 bauzas dansmith: I meant, before changing the opts
17:12:26 bauzas if you upgrade and just keep the same conf, you're not impacted
17:12:41 bauzas actually, I left another comment saying this
17:13:04 bauzas ie. keep existing behaviour in Train exactly like in Stein if untouched
17:13:12 dansmith okay let me re-read
17:13:36 bauzas dansmith: context being https://review.openstack.org/#/c/555081/22
17:13:54 dansmith right I know :)
17:14:13 bauzas https://review.openstack.org/#/c/555081/22/specs/train/approved/cpu-resources.rst@171 is the existing backwards compat concern I have => don't change anything
17:14:38 mriedem tssurya: gmann: i left some comments on the locked reason spec regarding filtering and sorting, but i'm not sure why locked is not a valid sort/filter parameter but locked_by is - even though we dont currently expose the latter
17:14:47 mordred gmann: all of those fields with OS-EXT prefixes are readonly aren't they?
17:14:49 bauzas https://review.openstack.org/#/c/555081/22/specs/train/approved/cpu-resources.rst@181 is the "what happens when you start playing with those new opts"
17:15:09 tssurya mriedem: I was just about to push :)
17:15:26 dansmith bauzas: okay, so what happens if you do make those changes on a compute node with instances?
17:15:28 tssurya oh had just added filtering based on the new keys will be allowed
17:15:28 bauzas oh man, I really thought the locked reason spec was not controversial :)
17:15:30 mordred gmann: in any case - we expose all of those without the prefix in sdk already - so I'm definitely in favor of that cleanup :)
17:16:02 mriedem tssurya: you can't filter on something that's stored in system_metadata
17:16:05 dansmith bauzas: as long as the same config means you don't have to move stuff that's okay, I thought you were kindof implying that they would have to move everything at some point though
17:16:06 bauzas dansmith: that's my point, in the spec, we say we reshape
17:16:18 bauzas when we start using those opts
17:16:22 tssurya bauzas: I thought so too! (when I initially proposed it)
17:16:30 mordred (although I think I need to add a way to express inside of sdk "this property comes from whichever of OS-EXT-AZ:availability_zone or availability_zone exists"
17:16:48 bauzas dansmith: nope, nope, keep same things in Train if config unchanged
17:16:56 dansmith bauzas: I would expect someone like CERN to really care about enabling this sort of thing and requiring everyone to move many gigs of data around just so we don't have to reshape is kinda icky
17:17:01 dansmith I mean, really icky
17:17:11 bauzas dansmith: I totally agree
17:17:21 tssurya mriedem: oh yea forgot ! I guess we discussed this too earlier in the spec when we were deciding where to put it
17:17:26 mriedem mordred: not necessarily, OS-DCF:diskConfig is on server create
17:17:40 gmann mriedem: they are all in response so did not get readonly thing completely
17:17:46 bauzas dansmith: that's why I'm in favor of a full service stop if operators start playing with new config opts in Train and have existing instances
17:17:58 mordred mriedem: ah - so it is. ok - that one will take a little extra effort - but shouldn't be too bad
17:18:04 mriedem gmann: OS-DCF:diskConfig is in server create and resize requests
17:18:28 mordred consuming whichever field name happens to be in the response is easy - knowing which field name one is supposed to send to the api is more effort
17:18:36 mordred but still doable and fine
17:19:03 mriedem i don't know that gmann was thinking about request params, and i just thought of OS-DCF:diskConfig since you saked
17:19:05 mriedem *asked
17:19:15 mriedem there could be others, it's a crusty api
17:19:19 dansmith bauzas: but I'm saying I think that we should be able to provide support for them stopping a compute, tweaking the params to enable, and then restart... with instances.
17:19:19 gmann ok, user data is one case?
17:19:40 mordred mriedem: I was mostly looking at the list in https://review.openstack.org/#/c/603969/10/specs/train/approved/api-consistency-cleanup.rst
17:19:40 mriedem user_data is not prefixed in the create request
17:19:49 bauzas dansmith: with a reshape ?
17:19:53 gmann OS-DCF:diskConfig will not be changed right
17:19:58 bauzas dansmith: sorry if I'm not getting you
17:20:01 dansmith bauzas: we can abort on startup if they have specified something that can't be reshaped, requiring them to move some stuff off before doing it, but requiring clearing every single compute node (over time) to turn that on really sucks
17:20:44 bauzas dansmith: okay so you're in favor of some automation
17:20:50 bauzas lemme reconsider that
17:20:52 mordred dansmith: just adopt cloud native design principles and stop writing files to disk. solves all your problems
17:21:15 dansmith mordred: heh
17:21:38 gmann mriedem: tssurya locked_by in valid sort/filter list was mistake. we can improve that in tssurya spec i think.
17:22:06 mriedem mistake because it's a field we don't even expose today?
17:22:11 tssurya gmann, mriedem: I will add locked" as a sort/filter key
17:22:36 mriedem i know at one point there was a comment in the code near these fields that said "don't use locked anymore" becaues locked_by implied locked
17:22:38 tssurya but as for the existing "locked_by" key in the whitelist, isn't that just a refactor of code ? since we don't expose it anyways ?
17:23:18 gmann mriedem: yes, we did not expose that and had in valid sort/fitler
17:23:34 mriedem tssurya: refactor of code?
17:23:45 gmann i tried to check the reason in original change but did not find any rational to add in whitelist
17:23:47 mriedem tssurya: as i mentioned in the spec, supporting filtering on locked_by could get weird,
17:24:11 tssurya mriedem: no I don't want to support locked_by based filtering as well
17:24:14 tssurya its useless IMO
17:24:18 mriedem becaues if we expose locked_by=admin or other, but only store admin or owner, then filtering on locked_by=other means we have to do something like "select * from instances where locked_by!='admin'"
17:24:38 dansmith filtering in the api on a non-db field isn't *super* terrible, but sorting is
17:24:47 gmann this one - https://review.openstack.org/#/c/408571/
17:24:57 bauzas dansmith: just to make sure https://review.openstack.org/#/c/555081/22/specs/train/approved/cpu-resources.rst@725 requires a reshape, right?
17:25:26 mriedem dansmith: i don't think sorting is a problem really here
17:25:29 bauzas ie. libvirt sees the options be set, raises a ReshapeNeeded, gets the inventories and allocations, move them
17:25:38 mriedem filtering would have to be special cased though, and locked_by is in the db
17:26:05 dansmith bauzas: properly representing allocations of dedicated cpus as PCPU right? Not even migration will fix those instances, so I would think reshape is the *only* way to fix that, no?
17:27:10 mriedem my pizza is getting dangerously cold
17:27:15 dansmith bauzas: unless you depend on scheduler/conductor to generate a new allocation for a properly hierarchical instance I guess, but.. that's just really super expensive when all you want to do is move some numbers around
17:27:32 bauzas dansmith: well, in a world before pcpu_shared_set, all instances are seen as using shared set of CPUs, so they need to be VCPU anyway, but the problem is that if we reserve, say CPU1, then we need to arbitratly assign instances using this CPU1 as PCPU
17:28:00 dansmith mriedem_away: I know we can filter on locked_by in the db, but I'm saying if we allow filtering on locked and then drop locked in the future, we can continue honoring that behavior from other fields
17:28:01 bauzas dansmith: but then there is an allocation ratio problem, since we don't want to oversubscribe on PCPU
17:28:32 dansmith bauzas: but L725 is talking about instances that already have dedicated cpus, but represented as VCPU right?
17:28:40 cdent efried: I'm moving on to the cross project nova+placement etherpad for my pre-ptg emails. a) cool with that? b) okay with the process I've been following c) anything especially I should or should not skip?
17:29:10 bauzas dansmith: yup, but the above example is still valid, nope?
17:29:20 bauzas it's just undocumented in the spec
17:29:55 bauzas that's what I tried to address in https://review.openstack.org/#/c/555081/22/specs/train/approved/cpu-resources.rst@181
17:30:27 bauzas actually, my wife yells at me because I need to go eating melted cheese
17:30:50 bauzas I need to disappear
17:31:18 bauzas https://en.wikipedia.org/wiki/Vacherin#Mont_d'Or
17:32:23 gmann mriedem_away: mordred let me check those fields from request point of view.
17:33:20 sean-k-mooney bauzas: stephenfin can ye review https://review.openstack.org/#/c/649882/ its related to both the cpus in placemnt spec and numa in placement
17:37:40 bauzas dansmith: left another comment trying to describe my concerns in https://review.openstack.org/#/c/555081/22/specs/train/approved/cpu-resources.rst@181
17:37:44 bauzas hopefully it will help
17:37:50 bauzas now I need to bail out
17:37:52 dansmith bauzas: I just commented summarizing my view
17:37:54 dansmith maybe that will help
17:37:56 dansmith go eat cheese
17:38:30 bauzas dansmith: okay, i'll join later
17:41:53 efried cdent: a) Sure, if you're done with nova reviews :P b) Yes, me likey. (Note that I am reading all of them, but only responding when I have something to say; I'm not sure there's positive value in an empty ack.); c) other than things you already mentioned (perhaps those should be re/moved from the main part of the etherpad?)
17:43:28 jmlowe cdent: Got a quick question about placement and vgpus
17:43:34 efried cdent: also on a) and b), I am likely to hold off on any further responses until tomorrow. Trying to focus solely on nova spec reviews today (though the gods are conspiring to make that challenging).
17:44:13 cdent a) I clicked on every link on the spec etherpad this morning and left reviews where I felt comfortable. sometimes I did not because my reaction was "oh look, yet more complexity for the five people who care" and didn't think that was too helpful, so moved on to something else, b) cool, c) I'm trying to make sure the etherpad exposes what has thread
17:44:20 cdent jmlowe: hola
17:45:05 cdent jmlowe: I can try to help, but the specifics of how the vgpus are being managed is not much in my wheelhouse
17:47:12 mriedem tssurya: so maybe a question that you don't want to hear right now, but do we really need to expose that locked_by field? it seems to be causing a lot more unnecessary churn on this spec than is needed

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