| Posted | Nick | Remark | |
|---|---|---|---|
| #openstack-nova - 2022-09-01 | |||
| 15:08:04 | gibi | (it is not just ironice) | |
| 15:08:05 | sean-k-mooney | so hehe i think we were reving this as libvirt only or at least i was | |
| 15:08:10 | bauzas | but I point out how fragile this is | |
| 15:08:17 | sean-k-mooney | gibi: ya i know | |
| 15:08:33 | bauzas | and again, this wasn't explained in the spec | |
| 15:08:34 | sean-k-mooney | ironic would just be the most painful | |
| 15:08:55 | bauzas | I was having concerns with this spec because I thought it wasn't really a needed usecase | |
| 15:08:55 | sean-k-mooney | bauzas: orgianly in the spec they planned to only do it for the metadta api | |
| 15:09:07 | bauzas | sean-k-mooney: no, they said about configdrives too | |
| 15:09:07 | sean-k-mooney | but then we pointd out config drive exsited and need to also work | |
| 15:09:16 | sean-k-mooney | bauzas: no i asked them to add that | |
| 15:09:25 | sean-k-mooney | they wanted api only | |
| 15:09:35 | sean-k-mooney | id did not want this to not work if you used config drive | |
| 15:09:35 | bauzas | sean-k-mooney: yes, but I also said it was a problem | |
| 15:10:06 | sean-k-mooney | so as it stands any driver that does not supprot the new metond will not report the trait | |
| 15:10:19 | sean-k-mooney | that need to be called out in the api ref | |
| 15:10:26 | sean-k-mooney | or other docs for this | |
| 15:10:39 | sean-k-mooney | we could put it in the driver suport matirx i guess | |
| 15:10:56 | sean-k-mooney | that proably beter long term | |
| 15:14:07 | sean-k-mooney | dansmith: only 6 failure for the extra paramater | |
| 15:14:28 | sean-k-mooney | i actully need the driver api change in the first patch too so ill add that | |
| 15:15:12 | gibi | I'm wondering about the virt driver api change | |
| 15:15:26 | dansmith | but bauzas' point about this not being supported by other drivers is legit | |
| 15:15:37 | dansmith | having features that look like swiss cheese is very confusing for users | |
| 15:15:47 | sean-k-mooney | gibi: i could drop that now actully | |
| 15:15:49 | gibi | I asked for it originally as I thought the reboot + regenerate logic can be orchestrated from the compute manager | |
| 15:15:52 | sean-k-mooney | if we just have the parmater | |
| 15:16:03 | dansmith | even if we reject for the api caller, it's still annoying to say "reboot works, but not reboot with userdata, but only if you're using configdrive" | |
| 15:16:09 | gibi | but the actualy implementation calls the regenerate call from the virt driver | |
| 15:16:22 | gibi | so it is less useful to have a virt driver method | |
| 15:16:22 | dansmith | gibi: reboot is a single call to virt, | |
| 15:16:26 | dansmith | and the regenerate has to happen in the middle | |
| 15:16:31 | gibi | dansmith: I see now | |
| 15:16:50 | dansmith | it's pretty unideal in general for sure | |
| 15:16:59 | dansmith | just saying, I think that's why it was done this way | |
| 15:17:05 | sean-k-mooney | so we dont need a new public methond in the virt driver api | |
| 15:17:05 | gibi | this is why I pointing out that the separate virt driver method is probably not needed | |
| 15:17:20 | sean-k-mooney | its just a new parmater to hard_reboot right | |
| 15:17:22 | dansmith | no, the publicness isn't the concern I think | |
| 15:17:36 | sean-k-mooney | right i know its the uniformatiy of the api | |
| 15:17:43 | sean-k-mooney | and not having it depend on the backend | |
| 15:17:51 | bauzas | agreed with dansmith my concern isn't the publicness | |
| 15:18:05 | bauzas | this is about the fact we depend on virt drivers | |
| 15:18:07 | gibi | it would be nice to do the reboot in 3 generic steps from the compute manager: stop, regenerate, start. But this is a big change | |
| 15:18:16 | sean-k-mooney | yep i get that but we have many things that depend on the virt driver | |
| 15:18:20 | dansmith | I definitely think these kinds of pinpoint features that look generic but only work in libvirt are a problem | |
| 15:19:01 | bauzas | sean-k-mooney: well, do all the virt drivers support to create *or* update the configdrives ? | |
| 15:19:18 | dansmith | create yes | |
| 15:19:23 | sean-k-mooney | vmware ironic libvirt yes | |
| 15:19:23 | dansmith | nobody supports update today AFAIK | |
| 15:19:27 | bauzas | dansmith: that's my point, I wasn't seeing the dependency when reviewing the spec | |
| 15:19:29 | sean-k-mooney | for create | |
| 15:19:35 | sean-k-mooney | not sure about powervm | |
| 15:19:53 | dansmith | gibi: the problem with that is things like vmware where I'm not sure where the config drive actually gets created, or even if generating it on the compute node and passing it to the virt driver as a file would necessarily be reasonable | |
| 15:19:55 | dansmith | since it's a remote thing | |
| 15:20:01 | sean-k-mooney | i can take a look and see what would be required for other driver quickly | |
| 15:20:07 | sean-k-mooney | ironic is the hard one | |
| 15:20:29 | sean-k-mooney | they pass the config drive via ipa | |
| 15:21:02 | gibi | dansmith: I see | |
| 15:21:03 | dansmith | like I think ironic passes the configdrive as a string to the api, | |
| 15:21:07 | dansmith | never generates it on disk | |
| 15:21:43 | sean-k-mooney | ah that might be how nova passes it to ironci but then ironic connects it to the vm via ipa or mounting it | |
| 15:21:50 | dansmith | yeah | |
| 15:22:01 | dansmith | it serializes it and then ironic writes it remotely I think | |
| 15:22:22 | dansmith | now, if compute generated the file I guess the driver could read and send it | |
| 15:22:30 | dansmith | but still, those are big changes requiring lots of testing | |
| 15:22:52 | sean-k-mooney | so really we would want the regeneration logic to be here https://github.com/openstack/nova/blob/master/nova/virt/configdrive.py | |
| 15:22:57 | sean-k-mooney | in the generic shared part | |
| 15:23:26 | sean-k-mooney | althogh maybe not | |
| 15:23:32 | sean-k-mooney | that does not quite do what i was expecting | |
| 15:23:35 | bauzas | I tend to agree with dansmith, we're playing with guns | |
| 15:23:55 | dansmith | well, I like playing with guns, but maybe.. playing with fire? :) | |
| 15:24:00 | bauzas | if we try to update a configdrive and this doesn't work, then our user won't be happy at all | |
| 15:24:28 | bauzas | dansmith: what you prefer | |
| 15:24:32 | bauzas | or playing with teslas | |
| 15:25:06 | dansmith | as long as you mean "teslas, the unit of charge, meaning playing with dangerous high-voltage" .. then sure :D | |
| 15:25:15 | bauzas | point is, we need to only accept to update the userdata if the configdriver correctly regenerated | |
| 15:25:18 | sean-k-mooney | https://github.com/openstack/nova/blob/master/nova/virt/ironic/driver.py#L1060-L1092 | |
| 15:25:28 | sean-k-mooney | so ironci jsut tuns it into a string yes | |
| 15:25:48 | bauzas | dansmith: like "driving a tesla with a 10% battery for 100km" | |
| 15:25:55 | dansmith | oh I see | |
| 15:26:02 | dansmith | that *is* scary :) | |
| 15:26:10 | bauzas | this *may* work | |
| 15:26:19 | bauzas | but before driving, you need to ensure you can do it | |
| 15:26:34 | bauzas | the same goes with configdrives | |
| 15:26:50 | sean-k-mooney | and they pass it in spawn and rebuild https://github.com/openstack/nova/blob/bcdf5988f6ae902dba9b41144a7b4a60688b627c/nova/virt/ironic/driver.py#L1189-L1191 | |
| 15:26:54 | bauzas | you only accept the userdata to be updated once you're sure your configdrive is correctly regenerated | |
| 15:27:12 | dansmith | so the feeling I'm getting here is that there are a lot of open questions at this point | |
| 15:27:19 | bauzas | since the user doesn't have an idea whether the userdata is updated and only relies on the fact he/she restarted the instance | |
| 15:27:32 | sean-k-mooney | bauzas: well that is already a problem today | |
| 15:27:40 | dansmith | sean-k-mooney: no it's not | |
| 15:27:45 | bauzas | today the userdata is immutable | |
| 15:27:53 | dansmith | sean-k-mooney: if you can only provide userdata during create, it's clear what userdata the instance sees | |
| 15:28:03 | bauzas | that reminds me the discussions we had when reviewing server groups /PUT | |
| 15:28:06 | sean-k-mooney | it is the config drive is not updated today if you atach interface or volumes or update the server metadta | |
| 15:28:10 | sean-k-mooney | the user data is not statble | |
| 15:28:16 | sean-k-mooney | btu in general the config drive can be | |
| 15:28:34 | dansmith | configdrive != userdata | |
| 15:28:43 | sean-k-mooney | yep that is my point | |
| 15:28:51 | sean-k-mooney | the config drive can be stale today the user data is not | |