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#openstack-nova - 2017-09-20
17:52:50 mriedem conductor, but note, that diff is against master branch code
17:53:20 tasker let me see if I can adapt to the branch that I'm using.
17:54:09 mriedem http://paste.openstack.org/show/621559/ is latest stable/newton
17:55:12 tasker cool, thanks. I'm going to step out for some "fresh air" and then apply this.
17:55:19 mriedem it does stand to reason that if this instance failed to build originally on those 2 hosts, that live migrating it there might fail too...but we don't know why it originally failed, could have been a resource claim issue at the time
17:55:36 tasker that's a fair observation.
17:57:56 melwitt yeah, often it's a failed claim. and also what if that compute host is eventually replaced over the lifetime of the cluster, making it a fresh candidate for several instances that might still avoid it because they once failed to build there back when it was a different machine
18:06:45 tasker live migration successful
18:08:17 tasker mriedem and melwitt -- thank you so much for helping to figure out what was wrong.
18:11:01 mriedem nice
18:11:07 mriedem tasker: want to open a bug? i have a fix with the test locally
18:11:40 tasker sure. let me collect my notes.
18:12:31 cdent dansmith: responded to some of your comments on https://review.openstack.org/#/c/500410/ . you semi-accidentally identified a separate problem. The nullable thing I’m not quite sure how to proceed, depending on what we want to do.
18:14:56 mriedem cdent: congratulations, you have the first complete blueprint in queens https://blueprints.launchpad.net/nova/+spec/placement-deregister-objects
18:15:35 dansmith cdent: replied, I don't think there's an issue.. just make those not nullable and (separately) always set them and I think we're good
18:24:25 cdent dansmith: except that they are only ever used on input, never output, so why bother reading them?
18:25:01 tasker mriedem: https://bugs.launchpad.net/nova/+bug/1718512
18:25:02 openstack Launchpad bug 1718512 in OpenStack Compute (nova) "migration fails if instance build failed on destination host" [Undecided,New]
18:25:07 mriedem thanks
18:25:19 dansmith cdent: because it's (effectively) free, it makes the object consistent
18:25:26 tasker I hope that summary / description is clear enough.
18:28:40 cdent dansmith: okay, I’m happy to do that. I’m not sure why consistency matters _now_ but if we’d like it as a general rule, that’s fine.
18:29:48 dansmith cdent: clearly it doesn't have a user now, but we're an abstract model on top of the data store and unless there is a reason not to, we should do that thing, IMHO
18:30:09 openstackgerrit Matt Riedemann proposed openstack/nova master: Ignore original retried hosts when live migrating https://review.openstack.org/505771
18:30:17 mriedem tasker: ^ i'm going to wip that and send something to the dev/ops lists for this, because if we change this for live migration, we also have to do it for cold migrate/evacuate and unshelve
18:30:23 mriedem melwitt: ^
18:30:43 melwitt ack
18:30:58 cdent dansmith: does YAGNI count as a reason not to?
18:31:42 dansmith cdent: I dunno what GNI is in there, but if you think there's a reason not to, then don't do it and we can just leave my -1 on there
18:32:52 cdent I’ve just always been brought up on the idea of not doing things unless there is a reason to do so, but as I said, I’m happy to do it and will do it.
18:34:24 mriedem if they are in the same table it seems easy peasy to just load them, it'd be one thing if we were lazy loading a big table join or something,
18:34:42 mriedem but if/when someone needs these, it's going to be weird debugging why they just aren't already in the object when it's read from the db
18:34:45 mriedem like every other object we have
18:34:48 dansmith mriedem: it's a join, but it's super tiny
18:34:52 mriedem oh
18:35:12 mriedem like the usages/consumers table join thing?
18:35:13 dansmith mriedem: like a 1:1 integer join
18:35:15 dansmith yes
18:35:16 dansmith consumers
18:35:39 mriedem i'm assuming at some point we actually intend on using these fields?
18:36:07 dansmith mriedem: if they're fields they should be loadable, and if we're never going to use them that way then maybe we shouldn't have them be fields
18:36:31 mriedem yeah i'd agree with that
18:36:36 mriedem i don't have context here though clearly
18:36:46 dansmith since consumer isn't a top level object in placement, getting them with allocations is the only way we can pull them out otherwise
18:36:51 dansmith unless we're querying for a consumer already
18:37:18 dansmith like if we needed to get all allocations against a resource provider
18:48:45 mriedem tasker: http://lists.openstack.org/pipermail/openstack-operators/2017-September/014233.html
18:49:08 openstackgerrit Chris Dent proposed openstack/nova master: WIP: [placement] manage cache headers https://review.openstack.org/495380
18:55:54 tasker mriedem: thanks! I'll keep an eye out on these.
18:57:45 tasker mriedem and melwitt: I want to thank you two for taking the time to work with me on my issues for the last few days. your support has been a positive influence in my cloudy days. with your help, I've been able to progress with my upgrade trials.
18:59:20 tasker If you two are ever in the Kansas City area, let me know. first round's on me.
19:05:32 mriedem tasker: cool, you're welcome. you hit some weird issues so i'm glad we flushed those out and have fixes
19:13:18 bauzas mriedem: back now, wazzup ?
19:14:45 mriedem bauzas: http://lists.openstack.org/pipermail/openstack-operators/2017-September/014233.html
19:18:09 bauzas holy shit
19:18:34 bauzas mriedem: honestly, no reason to persist that
19:18:58 bauzas mriedem: if some host wasn't accepted for an instance create, there is no reason it will be excluded for a live migration
19:19:14 bauzas at least, we should still verify it by the scheduler
19:20:17 bauzas mriedem: but here, the main problem is that I should possibly modify the ReqSpec object to have a specific way to say which fields are needed to be persisted and others not
19:20:43 bauzas mriedem: that's something we didn't discussed with alaski when he provided the .save() method
19:21:43 melwitt tasker: yep, thanks for helping us fix those bugs. and I learned yet more things I didn't know about live migration and retries
19:27:55 mriedem bauzas: yeah i was thinking about renaming the reset_forced_destinations() method to something like reset_for_move() and that would reset forced_hosts/forced_nodes/retry
19:28:08 mriedem so it could be handled for live migrate/cold migrate/unshelve and evacuate in the same place
19:29:05 bauzas mriedem: yeah, or just modify _get_update_primitives to disallow the non-needed fields
19:29:29 bauzas mriedem: like using a propery that'd give you which fields are non-persistent
19:29:51 bauzas that way a call to .create() or .save() would avoid persist those
19:29:57 bauzas persisting*
19:30:07 mriedem that won't help us for any existing req specs
19:30:12 bauzas but that wouldn't solve existing specs
19:30:14 bauzas yeah
19:30:49 bauzas okay, I think we could just rename reset_forced_dests()
19:30:59 bauzas and modify the comments of course
19:31:03 mriedem yeah
19:31:09 mriedem to fix all 4 move operations
19:31:13 mriedem i'm going to want to backport this too
19:31:18 bauzas want me to help on that or you feel enough brave ?
19:31:28 mriedem i'm brave
19:31:34 bauzas good boy
19:31:53 mriedem anything that can help me procrastinate from reviewing dansmith's efficient multi-cell instance list / sort thing
19:31:55 mriedem :)
19:32:06 bauzas honestly, I think it would be a good opportunity for discussing which fields shouldn't be persisted
19:32:20 bauzas like requested_destination
19:32:20 dansmith mriedem: my set should be pretty easy to follow I think
19:32:34 dansmith mriedem: I tried really hard to add functionality in layers
19:32:51 mriedem dansmith: yeah, i'm going to hit it now - i'll wait to deal with this reqspec stuff for tomorrow morning
19:32:55 mriedem gives me something to look forward to
19:40:17 cdent dansmith: there’s loads of pre-existings tests lying around that don’t require AllocationList to have a project and user. That makes it feel like more effort than it is worth to start requiring it in the Allocation object, so what I’m thinking of doing is not requiring it, but if they are there in the DB, loading it up when reading the object. Concur?
19:41:00 dansmith cdent: I'm not sure what you mean.. surely we require it from the API now right?
19:41:22 dansmith I guess one of the early microversions didn't require it so we _could_ have things in the DB that don't?
19:41:43 mriedem consumers requires project_id/user_id in the API in the latest microversion,
19:41:48 mriedem allocations doesn't
19:42:31 melwitt I thought PUT allocations required project/user
19:42:36 cdent they do
19:42:46 cdent but we don’t enforce that at the object level
19:42:51 cdent only the http api level
19:43:09 dansmith cdent: we should have migrated any existing allocations explicitly or incidentally
19:43:22 cdent what I’m saying is: to make the change to requiring things will change a pile of tests
19:43:31 dansmith cdent: if the http api always forces it (which it should) then we should raise an error when we hit one in the DB that doesn't, not just return an object with those things missing
19:43:45 melwitt the existing allocations get overwritten upon update with newer code to have project/user
19:43:53 melwitt (periodic update)

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