| Posted | Nick | Remark | |
|---|---|---|---|
| #openstack-nova - 2025-05-21 | |||
| 14:45:23 | sean-k-mooney | dansmith: right so you can requiest trait in the alias | |
| 14:45:36 | bauzas | but that requires PCI in placvement | |
| 14:45:48 | dansmith | bauzas: I only care about pci in placement :) | |
| 14:45:58 | dansmith | sean-k-mooney: I don't see that in the docs, can you link me? | |
| 14:46:03 | bauzas | ah, then provide device_spec with traits | |
| 14:46:13 | bauzas | and then request that trait thru the alias | |
| 14:46:17 | bauzas | https://docs.openstack.org/nova/latest/configuration/config.html#pci.device_spec | |
| 14:46:24 | bauzas | https://docs.openstack.org/nova/latest/configuration/config.html#pci.alias | |
| 14:46:40 | dansmith | ... I don't see in the docs how to request a trait with the alias | |
| 14:46:44 | sean-k-mooney | dansmith: https://github.com/openstack/nova/blob/master/nova/pci/request.py#L110-L115 | |
| 14:46:55 | dansmith | them's not docs :) | |
| 14:47:04 | sean-k-mooney | dansmith: it may or may not be but it was added with the pci in placement feature | |
| 14:47:05 | bauzas | dansmith: there is a traits dict key that you can add | |
| 14:47:08 | sean-k-mooney | so it shoudl be in the spec | |
| 14:47:14 | bauzas | request. This field can only be used only if [filter_scheduler]pci_in_placement is enabled. | |
| 14:47:14 | bauzas | character outside of [A-Z0-9_] with a single ‘_’, and prefixing the name with CUSTOM_ if not yet prefixed. The maximum allowed length of a trait name is 255 character including the prefix. Every trait in traits requested in the alias ensured to be in the list of traits provided in the traits field of the [pci]device_spec when scheduling the | |
| 14:47:14 | bauzas | An optional comma separated list of Placement trait names requested to be present on the resource provider that fulfills this alias. Each trait can be a standard trait from os-traits lib or it can be an arbitrary string. If it is a non-standard trait then Nova will normalize the trait name by making it upper case, replacing any consecutive | |
| 14:47:14 | bauzas | traits | |
| 14:47:17 | dansmith | https://docs.openstack.org/nova/latest/configuration/extra-specs.html#pci_passthrough:alias | |
| 14:47:32 | sean-k-mooney | that is the wrong doc | |
| 14:47:41 | bauzas | you don't specify the trait explicitely | |
| 14:47:49 | bauzas | I mean in the flavor | |
| 14:47:52 | dansmith | ohhh, you mean an alias in _config_ can be a trait instead of a vendor/product? | |
| 14:48:03 | bauzas | the flavor only requests an amount of that alias | |
| 14:48:18 | bauzas | and that alias is defined by having a traits key in it | |
| 14:48:28 | bauzas | dansmith: yes | |
| 14:48:52 | bauzas | and device_spec allows you to tag with traits some PCI devices automatically | |
| 14:48:54 | sean-k-mooney | dansmith: correct you can use placement resouce classes + traits instead of vendor and product id | |
| 14:49:01 | bauzas | just add traits to the device_spec dict in question | |
| 14:49:16 | dansmith | I see, I thought we were talking about the alias in the request | |
| 14:49:29 | sean-k-mooney | in the flavor no | |
| 14:49:31 | bauzas | that's transparent to the user or to the API admin | |
| 14:49:36 | dansmith | so the doc for alias needs a trait example I guess | |
| 14:49:40 | sean-k-mooney | this is all intentioally hiden form the flavor | |
| 14:49:50 | bauzas | dansmith: we have the conf docs | |
| 14:49:54 | sean-k-mooney | dansmith: ya https://docs.openstack.org/nova/latest/admin/pci-passthrough.html#pci-tracking-in-placement is where i was expectin git | |
| 14:50:06 | dansmith | sean-k-mooney: I understand, and that's how I expected it to work, I just didn't see the path to that alias requesting one of multiple things | |
| 14:50:07 | bauzas | but indeed the examples don't show< it | |
| 14:50:15 | sean-k-mooney | or maybe here https://docs.openstack.org/nova/latest/admin/pci-passthrough.html#configuring-pci-aliases-for-users | |
| 14:50:24 | dansmith | we need one here: https://docs.openstack.org/nova/latest/configuration/config.html#pci.alias | |
| 14:50:45 | dansmith | because that says you can use traits, but doesn't give me an example to see where that is the only thing used | |
| 14:50:53 | gibi | I can add that doc if that helps getting reviews on the eventlet series :) | |
| 14:50:57 | dansmith | I'll try this locally and then document if it works | |
| 14:50:57 | bauzas | dansmith: at least that's documented below in the list of accepted keys | |
| 14:51:04 | bauzas | cool | |
| 14:51:16 | dansmith | bauzas: I understand (now), but obviously not obvious to me :) | |
| 14:51:23 | bauzas | dansmith: we tested that with Uggla when he was working on vfio-pci | |
| 14:51:26 | bauzas | should work | |
| 14:51:26 | gibi | (I assume it works there are functional test coverage on it) | |
| 14:51:43 | sean-k-mooney | ya so in the devspec you can advertise them https://specs.openstack.org/openstack/nova-specs/specs/zed/approved/pci-device-tracking-in-placement.html#pci-device-spec-configuration and in the aliss you can requet them but we dont have that in the doc today | |
| 14:51:43 | bauzas | Uggla can give you some examples | |
| 14:51:45 | sean-k-mooney | https://specs.openstack.org/openstack/nova-specs/specs/zed/approved/pci-device-tracking-in-placement.html#pci-alias-configuration | |
| 14:51:45 | dansmith | gibi: sorry, I'm not farting around for no reason, I'm trying to get some other important stuff tested and this is in my way.. I promise I'm not ignoring your series for unimportant reasons | |
| 14:52:00 | gibi | ack | |
| 14:52:06 | dansmith | sean-k-mooney: yeah I think I understand the glue path now | |
| 14:52:08 | bauzas | gibi: I'd be more than happy to give a shot to your series | |
| 14:52:21 | bauzas | provided my meeting of meetings is done | |
| 14:53:00 | sean-k-mooney | so in https://docs.openstack.org/nova/latest/configuration/config.html#pci.alias | |
| 14:53:11 | sean-k-mooney | we do mention traits but only provide the eexample of a resouce class | |
| 14:53:39 | dansmith | sean-k-mooney: right | |
| 14:53:57 | dansmith | which is really just vendor/model (by default) so it doesn't look helpful to someone looking for it | |
| 14:57:25 | bauzas | we need one more example, I agree | |
| 14:57:34 | bauzas | without the product/vendor ID need | |
| 14:57:59 | bauzas | but IIRC, we still need to somehow define them, right Uggla ? | |
| 14:59:31 | Uggla | Give me a sec, need to reload the context. | |
| 15:00:26 | bauzas | long story short, can we skip the vendor/product ID settings in the pci alias ? I think we had to do something like providing a star (*) | |
| 15:01:26 | dansmith | bauzas: star does not help me here | |
| 15:01:36 | dansmith | but as I said, I will test this example shortly | |
| 15:01:45 | bauzas | dansmith: I guess I understood your case | |
| 15:02:00 | bauzas | you wanna request a group of arbitrary pci devices by traits | |
| 15:02:37 | bauzas | that's why I'm saying you shouldn't provide vendor and product IDs in the alias definition or you would restrict that list | |
| 15:03:00 | gibi | yeah so if you have two different devices with different product id then you can whitelist them via address (with full or partial match on the address) and connect them the the same resource class in the whitelist, you can add traits there as well. Then you can request that resource class in the alias | |
| 15:03:06 | bauzas | but IIRC, when we wanted to do that thing, we found some limitation that we fixed somehow I can't recall (maybe a star or something else) | |
| 15:03:38 | Uggla | Yes I think in the alias section we can skip product / vendor and only use ressource class or trait. | |
| 15:03:39 | gibi | the key is that you can use the same RC in multiple device_spec lines | |
| 15:05:49 | Uggla | Yep I updated the documentation for the alias section to highlight that product_id / vendor_id are optional. | |
| 15:07:14 | dansmith | I don't see that | |
| 15:07:34 | dansmith | ...that they are optional.. I do see the class example | |
| 15:08:02 | Uggla | dansmith, https://docs.openstack.org/nova/latest/configuration/config.html --> alias --> A JSON dictionary which describe a PCI device. | |
| 15:08:18 | dansmith | gibi: traits would be better for me that RC.. if they use the same RC, then I can't do inventory planning based on RC, and also, I might want to still request via RC for specific devices, or traits for generic "just give me a 256G nvme" | |
| 15:08:20 | gibi | https://github.com/openstack/nova/blob/221a3e89e8988bc664298106ee691a4e41ca71f9/nova/tests/functional/libvirt/test_pci_in_placement.py#L1759-L1772 | |
| 15:08:57 | dansmith | Uggla: yeah I said I see the example, just not that vendor/product is optional (as it says for traits and rc) | |
| 15:09:04 | gibi | dansmith: if you don't define the RC then the RC will be based on the product_id so you cannot have a single alias requesting it as a single alias cannot request two different RC | |
| 15:09:27 | dansmith | gibi: ... but I can request just a trait no? | |
| 15:10:14 | Uggla | dansmith, --> Note that [...] indicates optional field. | |
| 15:10:16 | gibi | you can request a set of traits | |
| 15:10:36 | gibi | but you need to eithe provide an RC or a product/vendor id in the alias | |
| 15:10:49 | gibi | otherwise we cannot createa placement allocation candidate query | |
| 15:11:56 | dansmith | Uggla: fine, but very not as obvious as: "resource_class: The **optional** Placement resource class name" | |
| 15:12:21 | dansmith | gibi: okay if that's the case then that's definitely not very well explained in the docs here | |
| 15:12:33 | dansmith | lemme try with just the trait so I can see what happens | |
| 15:12:36 | gibi | lets improve the doc | |
| 15:13:18 | gibi | if you provides just traits in the alias and no RC or vendor/product id then you will get that the alias is invalid | |
| 15:13:27 | gibi | (I hope : ) | |
| 15:15:07 | dansmith | I do not, on service startup at least | |
| 15:15:13 | Uggla | dansmith, I agree it could be better. | |
| 15:18:52 | gibi | dansmith: it is validated when the alias is used | |
| 15:19:12 | gibi | it was true for before PCI in Placement time | |
| 15:19:43 | dansmith | gibi: so, I might be missing something but it looks to me like I was able to create a server and it just silently ignored my pci request | |
| 15:20:30 | dansmith | https://paste.opendev.org/show/bkADIKJZwFGSAv3UcXCF/ | |