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#openstack-nova - 2025-03-26
18:37:47 dansmith so you mean the host (i.e. the cloud provider) would need to enable that for our instances, not that we could do that in our own images with grub
18:38:14 sean-k-mooney right we can enable it in the iamges we upload to them via nodepool
18:38:31 dansmith why are we not already doing that?
18:38:37 sean-k-mooney so we can turn on teh viommu in the ci image and enabel igb
18:38:41 sean-k-mooney it kills performance
18:38:49 dansmith ah
18:38:57 sean-k-mooney well if you actully use the iommu emulation
18:39:12 sean-k-mooney if its on and you do nothing im not sure what the overhead is
18:39:13 dansmith for regular jobs that don't use it at all would it matter?
18:39:17 dansmith okay
18:39:41 dansmith also, I've switched to using the virtio rng and it works very well and doesn't crash my first level guest each time.. any reason not to just use that for our test device?
18:40:07 sean-k-mooney none we just need a device that would not hard fault
18:40:21 sean-k-mooney if that work then we could do it today with our exisitng proviers
18:40:34 dansmith ack, the QXL kernel driver crashes in the first-level guest when it gets returned to it, but the rng seems to work fine
18:40:35 sean-k-mooney welll not teh xen rax nodes
18:40:39 sean-k-mooney but most of the others
18:41:12 dansmith okay maybe I'll see if that's doable
18:41:13 sean-k-mooney well i suspect the virtio-gpu might far better i used ot use virtio-blk device or virtio-net in the past
18:41:35 sean-k-mooney so what we need to so is add a new image and lable in node pool
18:41:51 sean-k-mooney then defien a new zuul nodeset that uses that and swawp say nova next to use that
18:42:07 dansmith why better than the rng? I just figure either of the other types are more likely to be complicated and more failure-prone
18:42:38 sean-k-mooney oh it was more i could add several neturon prots or cinder volumes if i needed more
18:42:57 sean-k-mooney but ya no reason not to use the rng
18:43:28 sean-k-mooney its mainlly needed to avoid slow boot up when there is low entropy
18:43:47 sean-k-mooney but once the first level vm is up the kernel hsould have enough to conitnue without it
18:44:19 dansmith oh I see, that would give us some extra devices I guess okay.. either way, if we get it all working it probably doesn't matter which we use and/or we could add aliases for all of them so jobs can configure their flavors
18:44:32 sean-k-mooney dansmith: so this is how you add image metadata vai node pool https://github.com/openstack/project-config/blob/master/nodepool/nb07.opendev.org.yaml#L26-L29
18:45:31 dansmith ack
18:47:38 sean-k-mooney i belive our stadnar images are all defiend here https://github.com/openstack/project-config/blob/master/nodepool/nodepool.yaml#L191-L461
18:47:48 sean-k-mooney the other wones were arm sepcific versions
18:48:40 sean-k-mooney i dont think we need to modify the image build jsut the upload to each cloud
18:48:50 sean-k-mooney or a cloud i guess to start with
18:50:13 sean-k-mooney dansmith: im sure you at least partly famiarly with this but the nodeset used for the jobs are typeiclly defined in devstack although we can define those in nova
18:50:41 sean-k-mooney we jsut need to refence the lable provided by node pool (the label is basicly and image an flavor mapped to each provider)
18:51:13 sean-k-mooney so you would basicly copy paste https://github.com/openstack/devstack/blob/master/.zuul.yaml#L154-L182
18:51:46 sean-k-mooney and change label: ubuntu-noble ro label: ubuntu-noble-with-iommu unless we just update ubuntu-noble to turn it on
18:52:03 sean-k-mooney in which case you coudl skip that stpe but i woudl impact everyone
18:57:27 dansmith vaguely, I don't think I've ever had to mess with it directly, but thanks for the pointers
18:57:48 dansmith I wonder if we could ask the virt team if there's any harm in just enabling viommu if it's not used.. if so that would make it easy
19:06:19 sean-k-mooney so this is the chart i remember seeing before https://kvm-forum.qemu.org/2021/vIOMMU%20KVM%20Forum%202021%20-%20v4.pdf#page=16
19:06:45 sean-k-mooney not that really talkign about the affect of enabling the viommu on a pci device that is passhth though to the guest
19:06:59 sean-k-mooney be it an ssd or a nic
19:07:32 sean-k-mooney and we can see the overhead is a 60-80% performance loss
19:07:57 sean-k-mooney but i dont know if we will see any performance hit for virual device like virtio-net or virito-blk
19:08:10 sean-k-mooney as such in ci it might not matter
19:09:15 sean-k-mooney that also with kernel 5.12, 6.14 just came out so this has proably impvoed over the last 4 years
19:10:37 sean-k-mooney the qemu they were using to test does not evne meet our current min requirements for nova and we are not exactly agressive with moving that forward
19:11:49 sean-k-mooney i think it would be wroth just trying it locally with some basic test with iperf and fio
19:12:29 sean-k-mooney and if you dont see any horible impact we could talk to the infra folks about trying it on one image in say the vexhost cloud or ovh adn see how it goes
19:19:45 dansmith ack, I should be able to do that.. maybe just tweaking the pool we run nova-next on or something and seeing if it looks to be performing the same for a week would be enough
19:21:09 sean-k-mooney yep
19:28:45 dansmith sean-k-mooney: so, I thought the iommu changes I was making in my first-level guest were to share/expose the actual iommu to the guest,
19:29:07 sean-k-mooney no
19:29:08 dansmith but reading danpb's post I'm thinking what I've been using is actually just the viommu stuff that nova would be enabling
19:29:17 sean-k-mooney yes
19:29:34 dansmith don't mind me, first day on the job people!
19:29:35 sean-k-mooney nova and qemu does not care if the host has an iommu or even if its enabeld
19:29:43 dansmith ack
19:30:08 dansmith so, also from reading danpb's post it seems like the non-passthrough devices should be unchanged with it enabled, but I'll do some testing to make sure
19:30:37 sean-k-mooney ack, that what i was expecting/hoping but i was unsure
19:31:43 sean-k-mooney the iommu can levage some host hardware accalration if its supproted but like vtpm its a purly vritual impelmetion by default
19:32:42 sean-k-mooney if i rememebr correctly we do enable caching by defualt https://libvirt.org/formatdomain.html#iommu-devices
19:34:57 sean-k-mooney ya we do https://github.com/openstack/nova/blob/master/nova/virt/libvirt/driver.py#L7987-L8019
19:35:33 sean-k-mooney so if the host support intel vt-d it can use it
#openstack-nova - 2025-03-27
08:24:51 opendevreview Rajesh Tailor proposed openstack/nova master: Fix disable memballoon device https://review.opendev.org/c/openstack/nova/+/945621
08:30:24 opendevreview Stefan K proposed openstack/nova-specs master: Add Cloud Hypervisor support spec https://review.opendev.org/c/openstack/nova-specs/+/945549
10:34:11 opendevreview Rajesh Tailor proposed openstack/nova master: Fix disable memballoon device https://review.opendev.org/c/openstack/nova/+/945621
11:14:53 opendevreview Merged openstack/nova stable/2023.2: Reproducer for bug 2098892 https://review.opendev.org/c/openstack/nova/+/942655
11:19:04 opendevreview Merged openstack/nova stable/2023.2: libvirt: Fix regression of listDevices() return type https://review.opendev.org/c/openstack/nova/+/942656
12:12:53 opendevreview Stephen Finucane proposed openstack/nova master: api: Adjust validation helpers for a single-method future https://review.opendev.org/c/openstack/nova/+/936365
12:12:54 opendevreview Stephen Finucane proposed openstack/nova master: api: Stop using wsgi.Controller.api_version to switch between API versions https://review.opendev.org/c/openstack/nova/+/936366
12:12:54 opendevreview Stephen Finucane proposed openstack/nova master: api: Only check minimum API version https://review.opendev.org/c/openstack/nova/+/940325
12:12:55 opendevreview Stephen Finucane proposed openstack/nova master: api: Add new, simpler api_version decorator https://review.opendev.org/c/openstack/nova/+/936367
12:12:55 opendevreview Stephen Finucane proposed openstack/nova master: api: Only run format checks on strings https://review.opendev.org/c/openstack/nova/+/936368
12:12:56 opendevreview Stephen Finucane proposed openstack/nova master: api: Simplify parameter types https://review.opendev.org/c/openstack/nova/+/936369
12:12:56 opendevreview Stephen Finucane proposed openstack/nova master: tests: Ensure all APIs have a response body schema https://review.opendev.org/c/openstack/nova/+/924598
12:12:57 opendevreview Stephen Finucane proposed openstack/nova master: doc: Add missing API samples https://review.opendev.org/c/openstack/nova/+/937012
12:12:57 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for hosts APIs https://review.opendev.org/c/openstack/nova/+/937047
12:12:59 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for instance actions https://review.opendev.org/c/openstack/nova/+/937048
12:12:59 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for hypervisors APIs (1/3) https://review.opendev.org/c/openstack/nova/+/937245
12:13:01 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for hypervisors APIs (2/3) https://review.opendev.org/c/openstack/nova/+/937246
12:13:01 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for hypervisors APIs (3/3) https://review.opendev.org/c/openstack/nova/+/937247
12:13:03 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for server IPs APIs https://review.opendev.org/c/openstack/nova/+/937608
12:13:03 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for remote consoles https://review.opendev.org/c/openstack/nova/+/940114
12:13:05 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for keypairs APIs https://review.opendev.org/c/openstack/nova/+/940115
12:13:05 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for image metadata APIs https://review.opendev.org/c/openstack/nova/+/940299
12:13:07 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for server topology API https://review.opendev.org/c/openstack/nova/+/940300
12:13:07 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for server diagnostics API https://review.opendev.org/c/openstack/nova/+/940506
12:13:09 opendevreview Stephen Finucane proposed openstack/nova master: api: Add response body schemas for server external events API https://review.opendev.org/c/openstack/nova/+/940508
12:18:40 opendevreview Merged openstack/nova master: FUP Remove unnecessary PCI check https://review.opendev.org/c/openstack/nova/+/944105
12:24:02 opendevreview Merged openstack/nova master: FUP improve comment accuracy and variable naming for tag removal https://review.opendev.org/c/openstack/nova/+/943124
12:35:18 opendevreview Merged openstack/nova master: FUP Add a warning to make non-explicit live migration request debugging easier https://review.opendev.org/c/openstack/nova/+/944133
12:35:24 opendevreview Merged openstack/nova master: FUP Update pci-passthrough and virtual-gpu documentation https://review.opendev.org/c/openstack/nova/+/944153
12:35:30 opendevreview Merged openstack/nova master: FUP: Improve libvirt fixture for hostdevs https://review.opendev.org/c/openstack/nova/+/945232
14:19:33 Vii Hello. Openstack 2024.2, I shelved the instance (I don't know if it's important on the host that was "compute service set --disable [hostname] nova-compute"). Now I can't unshelve this instance. There's an error in the nova logs: https://paste.openstack.org/show/bshRPNzpjA1ckFkGoa21/ does anyone have any ideas where the error might be?
14:20:46 dansmith Vii: it's timing out talking to neutron
15:09:22 opendevreview ribaudr proposed openstack/nova master: FUP improve and add integration tests for PCI SR-IOV servers https://review.opendev.org/c/openstack/nova/+/944106
15:55:57 opendevreview Dan Smith proposed openstack/nova master: Extend invalidate_rp to only invalidate cache https://review.opendev.org/c/openstack/nova/+/944148
15:55:57 opendevreview Dan Smith proposed openstack/nova master: Invalidate PCI-in-placement cached RPs during claim https://review.opendev.org/c/openstack/nova/+/944149
15:55:58 opendevreview Dan Smith proposed openstack/nova master: Support "one-time-use" PCI devices https://review.opendev.org/c/openstack/nova/+/943816

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