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#openstack-nova - 2017-05-19
19:24:41 mriedem but that's the network-vif-plugged and network-vif-unplugged events
19:24:47 artom Regardless of what the compute prepared for
19:24:55 dansmith also, when we support cross-cell migrations we'll want network-changed processed on both sides since they're separate databases
19:24:55 mriedem right
19:25:22 dansmith if we don't we'll end up with stupid bugs like info cache is as provided by the source compute until the next periodic refresh
19:25:31 mriedem dansmith: during a cross cell migration, wouldn't we get an InstanceNotFound on the source cell when trying to update it's nw info cache?
19:25:32 cfriesen okay, so can we add more info from neutron to reduce the number of queries nova has to do?
19:25:59 dansmith mriedem: no, if we do cross-cell migrations we'll have to create the instance in the target database before any of the migration stuff starts
19:26:11 mriedem ew yeah
19:26:12 artom Also, am I the only one who finds it completely mental that https://github.com/openstack/nova/blob/master/nova/compute/manager.py#L6856 is on the *compute*?
19:26:22 artom I'd put that somewhere more central, conductor I guess
19:26:34 dansmith artom: why?
19:26:35 prometheanfire mriedem: need a bug for http://logs.openstack.org/87/465887/4/check/gate-cross-nova-python27-ubuntu-xenial/19a9161/testr_results.html.gz ?
19:26:59 dansmith artom: you have more computes than conductors, and instance events don't come to conductor, they come to the compute(s) that are associated with the instances
19:27:05 cfriesen dansmith: it's a bit silly that both computes are simultaneously querying the same data from neutron
19:27:08 dansmith anything we can obviously do at the edges (computes) is better
19:27:24 mriedem prometheanfire: probably - without me looking into the actual tests
19:27:25 dansmith cfriesen: not in a cross-cell migration
19:27:30 artom dansmith, I guess I was thinking in the context of this overloading Neutron discussion
19:27:42 cfriesen dansmith: wouldn't you have separate conductors there too?
19:27:50 artom dansmith, but yeah, I'll shut up now ;)
19:27:53 prometheanfire mriedem: k, fyi, I think this will be blocking reqs updates on dogpile.cache
19:28:01 dansmith cfriesen: sure? but it's still twice the calls
19:28:17 cfriesen dansmith: for migrations in a single cell you could have the conductor get the data from neutron and then pass just the changed bits to both compute nodes
19:29:06 mriedem network-changed doesn't really have anything to do with the compute
19:29:12 mriedem so that one could be centralized
19:29:22 dansmith cfriesen: yes, you could have the api guess on all that and make those events different
19:29:32 mriedem network-vif-deleted and the vif plug/unplug ones call the driver so that's why they are on the compute
19:30:43 mriedem handling network-changed is an optimization that could be made at the top probably
19:30:48 mriedem but baby steps probably
19:31:38 dansmith mriedem: all events are handled by the computes now, so if you change that, you need to know which conductor (super or cell) to send events to, and then adding new things becomes a little less clear about where each is handled
19:32:10 dansmith making the operations that are happening less insanely heavy will yield much more benefit than cutting a big number in half in some situations
19:32:34 mriedem the former is what i'm trying to start with now yeah
19:32:40 mriedem by targeting the network-changed event to a single port
19:32:45 mriedem so we don't do the full nw info cache rebuild
19:32:48 dansmith yeah
19:33:01 dansmith I thought at one point we had a partial update thing like that
19:33:09 dansmith did we lose that or was it different?
19:33:20 mriedem not sure what you're referring to
19:33:31 cfriesen would it be reasonable for neutron to add more info about what exactly changed? (subnet, fixedip, floatingip, etc.)
19:33:47 mriedem cfriesen: maybe
19:33:54 dansmith we used to rebuild the whole cache every time and arosen did something to try to merge our networkinfo with just one change
19:34:27 dansmith cfriesen: you only get a tag in the event, but you could use that to signal what to refresh, yes, or have a different event like "floatingip-changed"
19:35:03 mriedem https://review.openstack.org/#/q/owner:aaronorosen%2540gmail.com+status:abandoned+project:openstack/nova
19:35:03 cfriesen even something like that could cut the number of neutron GETs down dramatically
19:35:10 melwitt dansmith: I put a lock around the cache access in https://review.openstack.org/465042 to address your comment
19:35:33 dansmith mriedem: no, this thing merged and caused a bunch of bugs, but I thought they all got squashed out
19:35:56 dansmith mriedem: anyway, not worth going to find it, it was 2013ish so just move on optimizing what we have now
19:35:57 mriedem dansmith: oh idk then, that would be like 3+ years ago now
19:36:00 dansmith yes
19:36:16 dansmith melwitt: I know, sorry
19:36:55 melwitt k, just in case you hadn't seen
19:37:04 mriedem anywho, i've got some patches to review which i promised (well didn't promise, but said maybe) i'd review, so going to do those first and then can cleanup this patch
19:39:01 cfriesen mriedem: dansmith: oh, and it turns out that once you have mriedem's "update the specific port" change, we don't really have any duplicate events for the same instance anymore
19:40:08 mriedem because they never were duplicates,
19:40:10 mriedem but nova just didn't know
19:40:12 cfriesen yeah
19:40:13 mriedem right?
19:42:25 cfriesen which actually means that the "vanilla" numbers for the neutron utilization would be much worse, since I had duplicate event removal in there.
19:42:46 mriedem do i get a large beer in denver for this?
19:42:52 mriedem s/beer/ginger ale/
19:42:54 cfriesen oh, definitely
19:43:38 melwitt I don't understand why I would get "This change depends on a change that failed to merge." on a set where when I rebase it locally, I don't see any merge conflicts or auto-merging
19:43:50 dansmith melwitt: depends-on?
19:44:07 melwitt I don't think I have any but I'm checking again
19:44:42 mriedem melwitt: there used to be a thing with zuul where if you rebased a large series, it couldn't keep up with the stream of events,
19:44:46 melwitt yeah, I don't have any Depends-On. ugh, wtf
19:44:50 mriedem and you'd get a merge conflict, even though there wasn't one
19:44:59 mriedem i saw that happening on artom's series the otherday
19:45:06 mriedem it was fixed for months, but might be back
19:45:08 mriedem in black
19:45:16 melwitt okay, I think it's still a thing then. there's 18 patches
19:45:41 artom mriedem, you mean the tagged attach series?
19:45:48 mriedem artom: is there any other?
19:45:50 artom Yeah, anything but the bottom patch gives merge conflict
19:46:06 artom mriedem, it's a secret that I'll reveal when I'm ready
19:46:22 melwitt haha
19:46:23 mriedem artom "tagged attach" lifshitz
19:46:34 mriedem is your new name when i give credits in my album
19:46:48 artom Yey credits!
19:47:10 mriedem right next to seymour duncan pickups
19:47:54 artom So I'll be in the 'Tools' section, gotcha
19:47:59 cfriesen mriedem: you play guitar?
19:49:29 mriedem cfriesen: in the long ago
19:49:56 mriedem they sit in cases in a closet in the basement next to a box of books and yankee candles
19:49:57 cfriesen this guy makes fan-fret basses in my city...I've visited his shop: http://www.dingwallguitars.com/
19:50:00 mriedem like a true suburbanite
19:51:15 nic Are there party hats?
19:51:22 openstackgerrit Dan Smith proposed openstack/nova master: Fix live migration devstack hook for multicell environment https://review.openstack.org/458537
19:51:23 openstackgerrit Dan Smith proposed openstack/nova master: Target cell on local delete https://review.openstack.org/464059
19:52:36 melwitt haha, yup
19:53:58 artom Speaking of party, we're not doing Hawaiian-nick Friday?
19:54:04 artom Not that I ever did it, personally
19:57:16 artom Dammit, length limit cut off the last letter
20:01:40 melwitt wear a hawaiian shirt
20:01:42 melwitt and jeans
20:01:45 melwitt if you want to
20:01:57 mriedem except peter
20:02:01 mriedem he has to come in on saturday
20:02:02 openstackgerrit Matt Riedemann proposed openstack/nova master: nova-manage: Deprecate 'log' commands https://review.openstack.org/453176

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