| Posted | Nick | Remark | |
|---|---|---|---|
| #openstack-nova - 2018-03-15 | |||
| 21:33:52 | openstackgerrit | Claudiu Belu proposed openstack/nova master: db: Adds live-resize to Migration model migration_type https://review.openstack.org/185961 | |
| 21:59:32 | mriedem | Kevin_Zheng_: you reported the bug related to this https://blueprints.launchpad.net/nova/+spec/add-server-group-remove-member-notifications but for telemetry and searchlight - given the states of those projects, do they actually care about solving this now? | |
| 21:59:40 | mriedem | https://bugs.launchpad.net/nova/+bug/1639152 | |
| 21:59:42 | openstack | Launchpad bug 1639152 in OpenStack Compute (nova) "Send out notification about server group changes when delete instances" [Wishlist,Confirmed] - Assigned to Takashi NATSUME (natsume-takashi) | |
| 22:00:11 | dansmith | mriedem: it requires conf | |
| 22:00:15 | dansmith | so I would kinda expect not | |
| 22:00:36 | dansmith | we will backport it because it's important enough, but I don't know that it fits the usual backport candidate mold | |
| 22:00:39 | mriedem | we can backport bug fixes sometimes as long as the config doesn't change any default behavior | |
| 22:00:51 | dansmith | it should be safe from that regard | |
| 22:01:04 | dansmith | it's really a feature used to fix a bug, IMHO, | |
| 22:01:04 | mriedem | by "we will backport" you mean the royal we? | |
| 22:01:11 | dansmith | so a bp isn't wrong I don't think | |
| 22:01:13 | dansmith | mriedem: we as in redhat | |
| 22:01:20 | mriedem | that's what i meant :) | |
| 22:02:02 | mriedem | alright i guess people that want it in stable can always patch out of tree if we're not going to backport upstream | |
| 22:02:15 | dansmith | I'm not saying we can't or shouldn't | |
| 22:02:16 | mriedem | i heard windriver has already had this for a year | |
| 22:02:23 | dansmith | I would have expected you to say no | |
| 22:02:39 | dansmith | if you think it's legit, then I think it's reasonable | |
| 22:02:42 | mriedem | having a blueprint tag on it makes it more awkward to backport | |
| 22:02:48 | dansmith | well, | |
| 22:02:50 | mriedem | i don't have the context on the thing, | |
| 22:02:51 | dansmith | it's not a bug in nova | |
| 22:02:56 | mriedem | just saw 'meltdown' | |
| 22:03:05 | dansmith | it's a bug in .. I dunno.. the whole arrangement of things | |
| 22:03:17 | mriedem | in computers? | |
| 22:03:22 | mriedem | just say computers | |
| 22:03:31 | dansmith | nova doesn't let you specify a thing that only the operator can know, and is needed to mitigate performance loss after applying the meltdown fixes | |
| 22:03:35 | dansmith | it's completely a nova feature, | |
| 22:03:55 | dansmith | but operators will need it to fix a bug or regressed behavior in lots of other things (kernel, qemu, etc) | |
| 22:04:16 | mriedem | hmm, this reminds me, | |
| 22:04:47 | mriedem | stable/ocata and stable/pike started crapping recently (right before the ptg) because of qemu / libvirt package updates for CVEs related to meltdown and spectre in the UCA | |
| 22:04:49 | dansmith | so I guess I'd leave it as a bp and just call it out in the backport as why we're making an exception | |
| 22:04:58 | mriedem | mnaser: ^ | |
| 22:05:01 | mriedem | you might be interested in that | |
| 22:05:16 | mriedem | https://review.openstack.org/#/c/534384/ | |
| 22:06:14 | mriedem | mnaser had to patch devstack on ocata and pike specifically to wait longer for nova-compute to start up b/c libvirt startup was going from like 10 seconds to a minute | |
| 22:06:18 | mriedem | dansmith: ^ sound like the same issue? | |
| 22:06:36 | dansmith | libvirt startup .. meaning a guest? | |
| 22:06:46 | mriedem | no, libvirtd | |
| 22:06:52 | mriedem | or the connection to libvirt | |
| 22:07:00 | dansmith | mm, I dunno, that's a question for kashyap I think | |
| 22:07:08 | dansmith | maybe if the fixes have been applied on the host, | |
| 22:07:16 | dansmith | but pcid isn't passed it makes our guests just super slow for some things | |
| 22:07:16 | mriedem | https://review.openstack.org/#/c/547676/ | |
| 22:07:18 | dansmith | so it could be | |
| 22:07:29 | mriedem | https://launchpad.net/~ubuntu-cloud-archive/+archive/ubuntu/ocata-staging/+sourcepub/8774271/+listing-archive-extra | |
| 22:07:40 | mriedem | the libvirt cve is i nthere | |
| 22:07:51 | dansmith | I mean, that's what the assertion is about the problem we're trying to solve | |
| 22:07:56 | dansmith | that _some_ things are like 30+% slower after the fixes | |
| 22:08:36 | mnaser | so the reason why it affected ocata and pike was because first of all devstack didnt use pike uca in pike, it used ocata uca | |
| 22:08:48 | mnaser | and the older release of uca didn't have this feature where it could ask qemu what cpu features it supported | |
| 22:09:06 | mnaser | so on libvirt start up with older libvirt instances, it would boot up a very small tiny qemu instance to probe it for things like cpu features etc | |
| 22:09:14 | dansmith | dear god | |
| 22:09:15 | mnaser | which would make the start up super sloooow | |
| 22:09:56 | dansmith | so that's unrelated I believe, unless the need for the new cpu feature discovery was because of the meltdown patch, | |
| 22:10:18 | dansmith | but I expect kashyap's fix won't solve that as it's a qemu-missing-a-thing problem | |
| 22:10:24 | mriedem | ok | |
| 22:21:59 | mriedem | dansmith: if you guys have vgpu people internally besides bauzas that can take a look at this https://bugs.launchpad.net/nova/+bug/1752463 | |
| 22:22:00 | openstack | Launchpad bug 1752463 in OpenStack Compute (nova) "Attaching virtual GPU devices to guests in nova" [Medium,Incomplete] | |
| 22:26:30 | melwitt | mriedem, dansmith: so we're agreed to approve https://blueprints.launchpad.net/nova/+spec/libvirt-cpu-model-extra-flags as a bp and we'll backport it, calling out in the backport why we're making an exception and backporting bp work. is that right? | |
| 22:26:54 | dansmith | melwitt: I'm cool with that yeah | |
| 22:27:51 | dansmith | mriedem: maybe, but that seems pretty low priority and can just wait for him to be back right? | |
| 22:28:24 | mriedem | dansmith: sure | |
| 22:37:01 | melwitt | mriedem: are you cool with the cpu model flags bp and the idea of backporting it? | |
| 22:37:51 | mriedem | i'm not crazy about it being a bp if we know we're going to backport it | |
| 22:38:04 | mriedem | i'd rather pretend it's not and say it's a bug fix | |
| 22:39:19 | mriedem | https://review.openstack.org/#/c/534384/5//COMMIT_MSG@28 definitely makes it sound feature-y too though | |
| 22:39:30 | mriedem | "besides the fix, you can also configure nova for other goodies!" | |
| 22:39:56 | melwitt | heh. yeah. this is definitely an odd case | |
| 22:40:55 | mriedem | now, if pcid as the extra flag is the only thing you'd care about if you only care about the fix, | |
| 22:41:24 | mriedem | then this could be a [workarounds] option with a boolean to set pcid or not, | |
| 22:41:27 | mriedem | and backport that | |
| 22:41:43 | mriedem | then the free-form wild west extra flags thing that is more of a feature could only be master | |
| 22:41:51 | mriedem | and we'd deprecate the workaround in master | |
| 22:42:00 | mriedem | dansmith: ^ what do you think about that? | |
| 22:44:26 | dansmith | I dunno, it seems like too much concern over a relatively minor thing | |
| 22:44:34 | dansmith | and I kinda expect that we'll backport the main thing ourselves anywaym | |
| 22:44:46 | dansmith | just so that people with queens and people with rocky don't need a different fix for this | |
| 22:44:55 | dansmith | but if that's how it has to go, then okay | |
| 22:46:21 | mriedem | i'm not the ptl, not my say, but i'd be more comfortable with that | |
| 22:46:34 | dansmith | I guess my point is, | |
| 22:46:49 | dansmith | we're going to backport the meat of the feature anyway, because we need it for the workaround | |
| 22:47:07 | dansmith | and constraining the workaround to one flag doesn't really do anything to make it safer, | |
| 22:47:19 | dansmith | unless the operator is going to just do crazy stuff with it (not sure what that would be even), | |
| 22:47:33 | mriedem | ^ is what i'm worried about, they try the 'other use cases' in stable, | |
| 22:47:39 | mriedem | and are all of a sudden reporting bugs about it | |
| 22:47:51 | dansmith | but if they're going to do that, | |
| 22:47:52 | dansmith | they'll do it with rocky when it's out | |
| 22:48:13 | dansmith | if we have a workaround, then people have to set that to make the thing work, and then when they roll to rocky (or S) and performance regresses for some reason they forgot about, | |
| 22:48:31 | dansmith | there will be bugs where we tell them that that workaround was a one-time deal and now they have to set pcid in this other field | |
| 22:48:44 | dansmith | just seems like it's too much monkeywork so we don't have a blueprint on a backport, | |
| 22:48:54 | mriedem | well, we'd use the workaround if it were set while it's deprecated, but we'd mark it deprecated to drop it later, but you'd have rocky to transition your tooling | |
| 22:48:56 | dansmith | when we can clearly point to not-our-fault reasons why this is needed and not high risk | |
| 22:49:15 | dansmith | yeah, it just doesn't seem worth the pain to me | |
| 22:49:50 | mriedem | precedent is another concern for me here, | |
| 22:49:57 | mriedem | true it's a no-op by default, | |
| 22:49:59 | cfriesen | dansmith: I agree with you, but I also suspect someone is going to try enabling pdpe1gb or vmx on queens. | |
| 22:50:08 | mriedem | but then people could use that justification against us later | |
| 22:50:12 | dansmith | cfriesen: so? | |