| Posted | Nick | Remark | |
|---|---|---|---|
| #openstack-nova - 2024-03-25 | |||
| 13:35:13 | bauzas | okay, I'm asking that because I don't know whether we could rather a blueprint instead of a bug | |
| 13:35:18 | sean-k-mooney | or get gmann's input | |
| 13:35:22 | sean-k-mooney | bauzas: its not a blueprint | |
| 13:35:24 | bauzas | sean-k-mooney: I created a new etherpad | |
| 13:35:46 | sean-k-mooney | bauzas: we dont actully need to change the api | |
| 13:35:48 | bauzas | sean-k-mooney: could you add it there ? https://etherpad.opendev.org/p/nova-dalmatian-ptg | |
| 13:36:02 | bauzas | sean-k-mooney: no, I'm not saying it would change the API | |
| 13:36:02 | sean-k-mooney | there is a filed called events in teh the action record | |
| 13:36:12 | sean-k-mooney | its currently empty for at least some of the instance actions | |
| 13:36:18 | sean-k-mooney | but apprenly stop populates it | |
| 13:36:30 | sean-k-mooney | so we would jsut be populating that with event for the rest | |
| 13:36:36 | bauzas | but it would return different actions between different API versions | |
| 13:36:40 | sean-k-mooney | that said we may or may not want a microversion to signal that | |
| 13:36:47 | sean-k-mooney | no | |
| 13:36:50 | sean-k-mooney | the actions woudl not change | |
| 13:36:55 | bauzas | (ie. Caracal wouldn't return some action while Dalmatian would) | |
| 13:37:09 | sean-k-mooney | the number of actions woudl be identiacal | |
| 13:37:15 | sean-k-mooney | the payload of the action woudl change | |
| 13:37:20 | sean-k-mooney | one sec ill get the example | |
| 13:37:35 | artom | sean-k-mooney, I believe you - I guess I'm asking if it was 100% reproducible, and did you need to do anything else besides the hw:numa_nodes=1 flavor extra spec to trigger a NUMA topology | |
| 13:37:50 | sean-k-mooney | bauzas: https://docs.openstack.org/api-ref/compute/#show-server-action-details | |
| 13:38:04 | bauzas | I mean the action would have a finish event https://docs.openstack.org/api-ref/compute/#show-server-action-details | |
| 13:38:34 | bauzas | so I don't know if this is an interop issue | |
| 13:38:34 | sean-k-mooney | yes within the events list in the action | |
| 13:38:53 | bauzas | but yeah we can discuss this with gmann sure | |
| 13:39:02 | bauzas | sean-k-mooney: can you add this bug to the PTG etherpad ? | |
| 13:39:03 | sean-k-mooney | its purly additive, populating an existing filed | |
| 13:39:07 | sean-k-mooney | bauzas: sure | |
| 13:39:14 | bauzas | thanks | |
| 13:39:43 | sean-k-mooney | artom: ya pretty much. not 100% but enough thaat it happend on the first try and several in a row | |
| 13:39:48 | bauzas | sean-k-mooney: yeah, my concern is that users would know which release is used for an API just by calling instance actions list :) | |
| 13:40:09 | bauzas | if you can find a finish event, then it's a Dalmatian version | |
| 13:40:36 | sean-k-mooney | yes although that would only matter if we didnt have a microversion fro dalamtion | |
| 13:40:50 | sean-k-mooney | and since we hope to have at least 1 for the maniala shares | |
| 13:40:55 | sean-k-mooney | im not sure this is a concern | |
| 13:41:16 | bauzas | well, this is not a concern from me, rather an open question | |
| 13:41:19 | artom | sean-k-mooney, so, NUMA placement is deterministic, right? (We don't promise it, but de facto it is)... So if this is not happening 100% of the time, it means there's a race or something similarly *non-deterministic* | |
| 13:41:25 | sean-k-mooney | personally i think this is somethign that shoudl be backported once fixed but again we can caht about that | |
| 13:41:41 | bauzas | I wonder #1 whether we need a microversion #2 whether we can backport it | |
| 13:41:48 | artom | When you say "reproduced", you mean the logs for the fitting of network metadata not appearing? | |
| 13:42:03 | bauzas | what I'd prefer is that #1 no and #yes :) | |
| 13:42:05 | sean-k-mooney | artom: deteministic in the sense that if you had only one host and you started with it empty and booted vms in the same sequence you would expect the same result yes | |
| 13:42:32 | sean-k-mooney | artom: obviouly in reality you have mutiple concurrent requests | |
| 13:42:33 | bauzas | sorry, meant : MHO : #1 no and #2 yes (no microversion, and yeah we can backport) | |
| 13:42:42 | sean-k-mooney | so you cant really prediect it 100% | |
| 13:42:47 | bauzas | but let's ask gmann and other folks | |
| 13:42:54 | sean-k-mooney | artom: but for functioanl tests it shoudl be prediable | |
| 13:43:10 | artom | sean-k-mooney, but in the context of a functional test with one host and one (or two) instances, it's fully predictable | |
| 13:43:32 | sean-k-mooney | artom: it should be yes | |
| 13:43:56 | sean-k-mooney | give me a minute to finish up a few more things and if you want we can try pair programming a repoducer in a bit | |
| 13:44:11 | artom | So if I'm not reproducing it (barring the possibility of me doing something wrong with my test), it means the cause is something non-deterministic... | |
| 13:44:32 | sean-k-mooney | artom: no it could mean our test fixtures are maskign it | |
| 13:45:36 | sean-k-mooney | on firday i tought i knew how to repoduce it but i need to recall what that was. | |
| 15:06:08 | dansmith | mnaser: do you have any sort of preprod environment you could test the eventlet hub switch-to-asyncio for us? | |
| 15:06:34 | dansmith | I'm worried about performance and stability issues by just blindly making that change, and I don't think a small-node-count devstack tempest run is good enough to say it's reasonable | |
| 15:07:04 | mnaser | dansmith: lol i was literally reading yesterday about the switch and searching the number of refs of eventlet in codesearch.opendev.org yesterday lol | |
| 15:07:07 | dansmith | and/or some willing tenant that could take the hit in the name of science? | |
| 15:07:20 | dansmith | ah, excellent | |
| 15:07:29 | mnaser | i assume this hits several services | |
| 15:07:45 | mnaser | so not really a "run a few computes with the new code" for example | |
| 15:08:30 | dansmith | no, we'd need coverage for really any service running eventlet in any form, which to me, means even nova-api which doesn't run eventlet proper, but which still depends on some of the plumbing | |
| 15:08:51 | dansmith | a couple compute nodes would be a start, and could be enough to signal "yeah, no, not going to work out of the box" | |
| 15:09:02 | dansmith | necessary but not sufficient | |
| 15:09:33 | mnaser | how intrusive are the changes in the code right now (i guess i can go try and find the review) | |
| 15:09:50 | mnaser | or since its the step 1 in the transition docs its just a one liner switching to the asyncio hub | |
| 15:10:12 | dansmith | yeah, the hub one-liner is what I'm talking about here | |
| 15:10:23 | dansmith | maybe check the latest discussion from this morning on the patch for context | |
| 15:11:04 | dansmith | https://review.opendev.org/c/openstack/governance/+/902585 | |
| 15:13:11 | bauzas | for me, I still need to bounce on this governance patch | |
| 15:13:46 | dansmith | I don't know what that means | |
| 15:14:14 | mnaser | dansmith: i wouldn't mind putting this in somewhere and testing but i think for me if there isn't anyone driving the work after the exercise ends up for no reason ;p | |
| 15:14:22 | bauzas | I meant to say "I would want to review it" :) | |
| 15:14:55 | dansmith | mnaser: okay, I think the point is that if it "just works" we'd start making that our default | |
| 15:15:15 | dansmith | mnaser: this is probably going to be everyone's problem pretty soon here so I'm not sure I'm too worried about it not getting attention | |
| 15:15:35 | dansmith | it already exploded and got some immediate attention a few months ago, which is why this spec exists | |
| 15:16:43 | mnaser | dansmith: in that case, if it "just works" in devstack, i'll be happy to flip the switch over in some envs here and report on what we're seeing | |
| 15:17:00 | mnaser | i'd have to double check what is the earliest version of eventlet that supports this change though | |
| 15:17:11 | mnaser | i.e. how recent of an openstack cloud you'd need to test this out | |
| 15:17:29 | dansmith | yeah, might need the recent stuff from eventlet I think | |
| 15:17:55 | dansmith | I think we're expecting it will "just work" from the devstack perspective, but I'm worried that under load we'll see performance and/o deadlock type issues | |
| 15:18:04 | dansmith | but yeah, we can get a sniff test first for sure | |
| 15:19:30 | mnaser | it seems we'll need to bump eventlet version | |
| 15:19:42 | mnaser | https://github.com/eventlet/eventlet/commits/e1afe7b387a2452c47a98b596c9451f9d95f7bdc/eventlet/hubs/asyncio.py | |
| 15:20:04 | mnaser | seems like it was added since 0.35.2 and thats not even in bobcat so it might require a new env | |
| 15:21:05 | mnaser | rally seems like a good idea, i'd be happy to help stand up and env to run rally against since one of the concerns i'd have is well -- if you need to run caracal for this i dont know if i can find something that's running that with enough of a workload :) | |
| 15:21:22 | dansmith | okay | |
| 15:22:19 | mnaser | i assume the challenge is not going straight to asyncio is the fact there are a lot of eventlet based dependencies such as oslo messaging etc? | |
| 15:22:49 | dansmith | parse error | |
| 15:22:53 | JayF | That's the idea, we want to have a migration where openstack can run eventlet/asyncio side by side so we can migrate off eventlet (and onto asyncio, depending on the outcome of testing+the goal) | |
| 15:23:04 | dansmith | the challenge *with* going straight to asyncio/ | |
| 15:23:30 | dansmith | mnaser: asyncio is a vastly different programming model from eventlet | |
| 15:23:36 | clarkb | asyncio is cooperative and eventlet pretends to not be | |
| 15:23:38 | clarkb | ya that | |
| 15:23:43 | dansmith | mnaser: it's not a small change, it's a rewrite everything sort of deal | |
| 15:24:04 | mnaser | ah, so ctrl+f and looking at the number of 'eventlet' references is not an indicator of how challenging it might end up being | |
| 15:24:11 | dansmith | what we're discussing is a hack to let eventlet use asyncio as its sort of thread-switching engine, but it's just one step | |
| 15:24:20 | dansmith | mnaser: not even remotely close to that no :) | |
| 15:24:23 | sean-k-mooney | mnaser: correct its not | |
| 15:24:32 | dansmith | mnaser: ctrl-f and search for "def.*" would be more accurate :) | |
| 15:25:21 | dansmith | switching to real threads would be more of what you're describing, since the model is the same | |