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#openstack-nova - 2020-11-13
14:26:50 openstackgerrit Radosław Piliszek proposed openstack/nova master: [docs] Fix a placement client's command https://review.opendev.org/762663
14:29:54 f0o not sure where to go from here
14:30:14 sean-k-mooney can you paste the xml for the instace somewhere
14:30:19 f0o sure
14:30:47 sean-k-mooney there is an option to contol the reboot action but we dont set it but im just wondering if anything else is there that was generated by libvirt
14:31:11 sean-k-mooney libvirt modifies the xml we give it an fills in things like pci address automatically
14:31:56 f0o http://paste.openstack.org/show/oGhApPwoy0lNe5cKmV0G/
14:32:35 sean-k-mooney <on_poweroff>destroy</on_poweroff>
14:32:36 sean-k-mooney <on_reboot>restart</on_reboot>
14:32:38 sean-k-mooney <on_crash>destroy</on_crash>
14:32:41 sean-k-mooney so those are what i expect
14:33:00 sean-k-mooney <on_reboot>restart</on_reboot> is what i was wondering about
14:33:16 f0o so that seems alright then?
14:33:55 sean-k-mooney yes so what could be happening is a race between the periodic task and the vm reboot
14:33:55 f0o nova-compute-kvm version 2:20.0.0~rc1-0ubuntu3~cloud0 and qemu-kvm version 1:4.0+dfsg-0ubuntu9~cloud0 (just in case)
14:34:10 sean-k-mooney is it happeing everytime
14:34:16 sean-k-mooney or jsut some times
14:34:29 f0o it's happening the majority of times
14:34:48 f0o there are some exceptions to it, but by now I'd wager that most times it gets stuck in paused
14:35:13 sean-k-mooney hum ok the interval is 10 minutes for the update by default
14:35:14 sean-k-mooney https://docs.openstack.org/nova/latest/configuration/config.html#DEFAULT.sync_power_state_interval
14:35:38 sean-k-mooney i assume you have not made that run faster
14:35:48 f0o nope
14:35:56 f0o config is very trivial, most are left as defaults
14:36:10 sean-k-mooney https://docs.openstack.org/nova/latest/configuration/config.html#workarounds.handle_virt_lifecycle_events
14:36:32 sean-k-mooney so you might want to set that to false
14:36:38 sean-k-mooney it look liek this is a know race
14:37:29 f0o ok let's give it a shot
14:37:35 sean-k-mooney if you have the interval at its default then setting that to false should be fine
14:38:21 sean-k-mooney that would have to be set on the compute nodes fyi
14:38:22 f0o set and restarting nova-compute
14:38:28 sean-k-mooney cool
14:38:45 f0o let's give it a shot
14:41:36 sean-k-mooney f0o: by the way the reason we default to haneling event i belive is for ironic
14:43:57 f0o makes sense
14:44:20 f0o at first I thought I was going insane but now that it became more frequent I figured I ask
14:47:04 sean-k-mooney hopefully that option will help
14:47:47 sean-k-mooney the main sideefct is that if you do poweroff in the guest then it wont be refected in the api/db until the interval expires
14:48:02 sean-k-mooney e.g. up to 10 mins form power off by efault
14:48:30 f0o that should be fine
14:48:37 sean-k-mooney that is genreally and ok tradeoff and you can adjust the interval if you want too
14:48:38 f0o worst case I lower the update interval
14:48:45 sean-k-mooney yep
14:53:00 f0o [ 652.025665] reboot: Restarting system .... let's hope it comes back up :D
14:56:10 f0o I can see the qemu process running and consuming 30% cpu but nothing seems alive in it
14:56:56 f0o vnc shows guest hasnt initialized display and view logs is only showing that reboot message
15:00:53 f0o During _sync_instance_power_state the DB power_state (1) does not match the vm_power_state from the hypervisor (3). Updating power_state in the DB to match the hypervisor / Instance is paused unexpectedly. Ignore.
15:00:55 f0o again :<
15:02:19 f0o process is still running and eating up 30% cpu tho, not sure what it's actually doing there
15:49:26 sean-k-mooney f0o: that is sounding more like a qemu bug then an openstack one
15:49:41 sean-k-mooney it sound like its not actully restating properly
15:50:58 f0o cool :D
15:51:06 openstackgerrit Ghanshyam Mann proposed openstack/nova master: DNM: Testing system scope in tempest https://review.opendev.org/740124
15:51:11 f0o just my luck
15:52:09 tacco hey everyone. Anyone knows why i only get 64VCPUs on a HV with 256 CPU Cores? over commiting ratio is 1.0 :(
15:52:28 tacco AMD EPYC 7742 64-Core Processor
15:53:24 gibi dansmith: hi! Do I understand correctly that the service version check at https://review.opendev.org/#/c/729563/17/nova/compute/api.py@4162 can see version 54 and allowing the shelve call with accelerators while the RPC is still can be manually pinned to < 5.13 and therefore the compute will not the accel_uuids param and therefore not handle the acceleratos properly?
15:53:53 gibi * will not get the accel_uuids
15:54:23 dansmith I'll have to look at that decorator, I think that just got added, right?
15:54:38 tacco i see processor: 255 and cpu cores: 64 in /proc/cpuinfo is this something like HT on Intel CPUs? but only can provide the "real" cores to the VM?
15:54:54 tacco cause i have 250CPUs in my flavor
15:55:03 tacco the VM then spawns with 64CPus
15:55:10 f0o Uhm
15:55:18 f0o 7742 shows as 64 cores
15:55:26 f0o HT stuff doesnt really count afaik
15:55:53 dansmith gibi: yikes, that makes an uncached cross-cell db lookup for every single call of that method :(
15:56:05 gibi dansmith: not too long ago, but it basically calls get_minimum_version_all_cells
15:56:27 f0o tacco: inside the vm you dont see the HT threads?
15:57:06 tacco in the VM at proc/cpuinfo i see only 64 but the vm was spawned with a flavor with 250 vcpus
15:57:47 tacco thats kinda strange and cli hypervisor list also shows 256 CPUs
15:59:20 dansmith gibi: commented on that patch, see if that helps
15:59:34 gibi thanks
16:05:36 tacco i see this seems to be two physical CPUs with 64 cores and 128 threads. that makes sense. But no clue why the VM only got 64Cpus if in the flavor are 250 specified. anyway. will have to dive deeper :D
16:08:10 f0o I'm happy to swap issues with you tacoc :D
16:08:25 f0o other than my dyslexia today lol
16:09:47 tacco always nice to be a usefull person :D
16:12:30 gibi dansmith: you confirmed my fears, thanks
16:12:36 dansmith gibi: ack
16:12:54 dansmith gibi: honestly that decorator seems like a bad idea to me.. that's a lot of overhead hidden in a decorator
16:13:22 dansmith it should at least use a cached value, but I'd prefer we did things like I described, which is rely on the rpc version and a raise from rpcapi
16:13:30 sean-k-mooney tacco: there was a libvirt bug realted to numa reporting and amd but perhaps there are others
16:13:51 sean-k-mooney tacco: what do you see on the host if you do nprc
16:14:04 gibi dansmith: agree. I missed the heavy weightness of that decorator impl in previous reviews.
16:14:19 sean-k-mooney tacco: can you provide the output of virsh capabilities for me in a paste and ill quickly take a look
16:14:21 dansmith gibi: oh actually, I forgot that we cache in the service object itself, so I guess not as bad, but still, it leaks the rpc problem so it'd be better to use that
16:14:55 tacco nproc shows me 256 as expected.
16:15:18 sean-k-mooney tacco: also the vm xml. if possible. i know some kernel have a process limit built in so just want to check if the xml has 64 or 250 cores
16:15:26 tacco one sec. will do so.
16:16:11 gibi dansmith: ack
16:19:45 tacco sean-k-mooney: http://paste.openstack.org/show/xs49lPLHXUPh43AeceZs/
16:20:05 tacco thats the dumpxml from the VM
16:20:07 sean-k-mooney <nova:vcpus>250</nova:vcpus>
16:20:13 tacco virsh capas on the way. :)
16:20:14 sean-k-mooney <vcpu placement='static'>250</vcpu>
16:20:26 sean-k-mooney so nova is telling libvirt/qemu to use 250
16:20:54 tacco ok, but inside the VM i only see 64 when i do cat /proc/cpuinfo hm.. maybe some problems with the image
16:20:56 sean-k-mooney <topology sockets='250' cores='1' threads='1'/> in a really dumb way but this is the default
16:21:25 tacco yes would enable numa pinning later
16:21:27 sean-k-mooney try adding hw_cpu_sockets=2 hw_cpu_theads=2 to the image
16:21:59 tacco would keep this in the flavor, because i would like to keep this as a seperate aggregate only available for "some" users

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