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#openstack-nova - 2019-08-27
18:02:21 dansmith there should be renos about this
18:02:33 efried ack
18:02:46 dansmith change-consecutive-boot-failure-counter-to-weigher-428de7da0ed2033a.yaml
18:03:25 efried dansmith: okay
18:03:26 efried so
18:04:00 efried this is now up to deployers installing their own weigher?
18:04:12 dansmith eh?
18:04:19 dansmith did you read the reno?
18:04:56 dansmith efried: https://review.opendev.org/#/c/572195/
18:05:01 efried ack
18:05:18 dansmith added a weigher, changed the meaning of the threshold for compatibility reasons
18:05:25 mriedem https://docs.openstack.org/nova/latest/user/filter-scheduler.html#weights
18:05:28 mriedem BuildFailureWeigher
18:07:24 dansmith efried: you hip to that jive?
18:07:58 efried Still trying to grok the implications.
18:08:31 efried So in a biggish cloud, if I have a bunch of failures in a row on a particular host, even if I don't hit the default multiplier, it's still going to make scheduling to that node way less likely
18:08:36 dansmith mriedem: beat you to the youtube ref: https://www.youtube.com/watch?v=sgW3RxKdN0Q
18:09:04 dansmith efried: hit the multiplier meaning "change" it?
18:09:27 efried sorry, no, I just mean...
18:09:58 efried IIUC the default multiplier is really big so that by default you won't effectively-disable a compute until it's seen a really lot of build failures.
18:10:12 dansmith efried: no
18:10:20 dansmith efried: read the reno and commit for reasoning about the multiplier
18:10:39 dansmith efried: it has to compete against disk weigher, which is like scored by mb free or something
18:11:12 dansmith efried: a big multiplier makes it more likely to have an effect, not les
18:11:14 dansmith *less
18:11:18 efried ah
18:11:30 dansmith and the threshold is now just "report failures if nonzero", so it's not a threshold
18:11:57 dansmith if you want it off, set the "threshold" to zero and computes won't even report the number
18:12:13 efried ack
18:12:14 dansmith and if you do, then you tune the multiplier based on whatever else you have configured
18:15:11 efried got it. Thanks dansmith. (And no, mriedem, I'm helping donnyd figure out why his CI hosts get effectively-disabled-without-actually-being-disabled when they spend some time trying to boot with not-yet-ready images)
18:16:07 mriedem :P
18:16:14 mriedem o-)
18:16:16 efried dansmith: save me tracing the code, does it still have the "reset to zero" behavior as soon as we get one success?
18:16:30 dansmith IIRC yes
18:16:47 dansmith efried: https://review.opendev.org/#/c/572195/6/nova/compute/manager.py
18:16:54 donnyd thats pending it ever actually gets rescheduled
18:17:15 donnyd I have enough space that essentially it doesn't
18:17:19 efried yeah
18:17:23 dansmith https://review.opendev.org/#/c/572195/6/nova/compute/stats.py
18:17:30 efried dansmith: is this one of those things that you should theoretically be able to reset via SIGHUP?
18:17:34 dansmith see my FIXME in there
18:17:40 dansmith efried: for sure
18:18:22 efried k. btw, not sure if you saw the update, but between bnemec and me, SIGHUP is (soon to be) fixed.
18:18:38 efried soon as we can get this code merged & released
18:21:53 donnyd What i really need is a faster way to download glance images so this isn't an issue
18:24:13 efried just walk a flash drive across the room
18:24:28 donnyd LOL efried
18:25:31 donnyd Well the glance image store is on an nvme drive that will move at the speed of the rest of the network... however glance doesn't feel that same way, and limits my download speeds to what one core can do... which is about 100M/s
18:25:59 donnyd I think it has something to do with requests if I am not mistaken
18:33:02 sean-k-mooney donnyd: are you useing a 1G network for your managment network
18:33:09 donnyd 10
18:33:19 donnyd and the controllers are all 40
18:33:48 donnyd So on the control plane for the compute side 10, and controller side 40
18:33:55 mriedem donnyd: are you using ceph?
18:33:58 donnyd no
18:34:15 donnyd filestore is the fastest i have measured thus far
18:34:18 melwitt mriedem: just fyi if you didn't see, I updated the multi-cell archive patches yesterday night
18:34:41 mriedem melwitt: i didn't, and was going to look about 30 minutes ago, but was distracted, but i'll look in a bit, thanks
18:34:50 donnyd i tried cinder and swift backends, and they only made it slower
18:35:15 melwitt mriedem: coolness, thanks
18:35:19 donnyd if I was on ceph, there would be no wait time at all
18:35:19 mriedem donnyd: have you tried pre-caching the images on the computes when you have a new image?
18:35:25 melwitt and sorry for the delay
18:35:59 mriedem donnyd: the only thing i'd have to check is if there is some config to keep the image cache manager periodic from deleting the images if there are no guests on the host using them
18:36:02 donnyd mriedem: I didn't know that was an option... but I am also pretty sure nodepool is all over it whenever there is a new image
18:36:48 mriedem the image cache stuff in nova isn't documented at all outside of config (i don't think anyway), so i wouldn't be surprised
18:36:49 donnyd mostly the issue is when new images are loaded, they can't be downloaded fast enough by compute
18:36:54 mriedem i don't know it all that well either
18:37:10 mriedem right, by pre-caching you wouldn't need compute to download them, the images would be there
18:37:26 mriedem but that's something yo'ud have to orchestrate outside of nova
18:37:48 donnyd well nodepool asks for them nearly the instant that they are active in glance
18:37:56 donnyd at least from what i can see
18:38:14 mriedem ok yeah so maybe wouldn't help
18:38:43 donnyd when you say pre-caching, i am thinking you mean have nova launch something based on the new image and then kill it immediately after its active.
18:39:00 mriedem that's one way
18:39:05 mriedem probably the easiest
18:39:16 donnyd I don't know how to setup the http store for glance and have it download direct from say an apache server
18:39:21 mriedem or you could have something push the image here https://docs.openstack.org/nova/latest/configuration/config.html#DEFAULT.image_cache_subdirectory_name
18:39:58 mriedem jroll: doesn't verizon do extensive image pre-caching?
18:40:08 melwitt pre-caching (warming the cache by booting instance with new image 1 per compute host) is the only other way I know to deal with avoiding download speed issues, other than using ceph. I know at least in the past they did the cache warming thing at yahoo
18:40:24 mriedem ok yeah that ^
18:40:25 jroll if we do it idk about it
18:40:26 melwitt mriedem: haha, my slow message composition strikes again
18:40:28 mriedem was going to ask penick but he's not here
18:40:31 jroll rax did some of that too
18:40:34 donnyd I thought about setting up a share from my block image server that would share _base across hypervisors
18:40:44 donnyd making it only have to download once
18:40:48 donnyd which is acceptable
18:41:05 donnyd but i am not sure of the other performance implications of doing such a thing
18:41:11 jroll mriedem: is there something I can help with around that?
18:41:13 mriedem yeah, people do that https://bugs.launchpad.net/nova/+bug/1804262
18:41:15 openstack Launchpad bug 1804262 in OpenStack Compute (nova) "ComputeManager._run_image_cache_manager_pass times out when running on NFS" [Medium,In progress] - Assigned to Matthew Booth (mbooth-9)
18:41:27 mriedem jroll: not really
18:41:33 jroll k :)
18:41:43 mriedem i thought i saw something (blog/talk?) where penick was talking about doing this
18:41:54 jroll possibly
18:42:08 mriedem i was probably surprised because it was some non-baremetal thing
18:42:11 donnyd I was only going to mount _base so the first hypervisor to download the image would speed it up for the rest
18:42:15 jroll just not sure if there's a question to be answered or if you're just curious

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