| Posted | Nick | Remark | |
|---|---|---|---|
| #openstack-nova - 2018-03-27 | |||
| 20:13:13 | dansmith | and it may cut it up or not | |
| 20:13:19 | dansmith | placement has no bidness knowing or caring about that | |
| 20:13:27 | jaypipes | sean-k-mooney[m]: that was the whole point of granular request groups. to allow the caller to say "give me a total of 2 of these things, but make sure I get 1 each from different providers". | |
| 20:13:44 | efried | jaypipes: No, not that. | |
| 20:13:51 | jaypipes | yes, yes that | |
| 20:13:53 | dansmith | efried: yes that | |
| 20:13:58 | dansmith | exactly that | |
| 20:14:00 | efried | jaypipes: "Give me two of these things, but each one has different traits" I'll grant you. | |
| 20:14:14 | efried | ...which has the effect of dividing them across two providers. | |
| 20:14:19 | dansmith | efried: if you ask for two things with no trait difference, I think the assumption is you want them from different places | |
| 20:14:31 | efried | But if they *don't* have different traits, putting them in different groups does *not* give you different RPs. | |
| 20:14:45 | dansmith | you're saying that, | |
| 20:14:47 | dansmith | but I disagree that that is how it should be | |
| 20:15:00 | dansmith | so if you're talking about your patches as of now, then okay.. but then we should find and -2 those :) | |
| 20:15:23 | efried | dansmith: http://specs.openstack.org/openstack/nova-specs/specs/rocky/approved/granular-resource-requests.html#semantics third bullet. | |
| 20:15:39 | jaypipes | agree wholeheartedly with dansmith. I don't see any logic in granular request groups *ever* meaning "give me two of these exact same resources, but allow them both to be from the same provider" | |
| 20:16:06 | dansmith | efried: okay so that's what I was saying above.. we either decide if they should be different (what I've been assuming) or they're not and they're effectively merged | |
| 20:16:11 | dansmith | efried: your bullet says the latter | |
| 20:16:22 | dansmith | which, if we've decided, then cool, but I think that was/is a mistake | |
| 20:16:30 | efried | jaypipes: You would never want two VFs from the same PF? | |
| 20:16:33 | jaypipes | agreed it was a mistake. | |
| 20:16:45 | dansmith | efried: two VFs from one PF is VF=2 | |
| 20:16:51 | jaypipes | efried: if you did, you would say resources:SRIOV_NET_VF=2 | |
| 20:16:53 | dansmith | efried: not VF=1,VF=1 | |
| 20:16:54 | sean-k-mooney[m] | jaypipes: it does simply one case which is merging resouce request form the image/flavor/port/volume | |
| 20:17:02 | sean-k-mooney[m] | jaypipes: it also has implcation for you cpu spec | |
| 20:17:18 | dansmith | what jaypipes said | |
| 20:17:39 | efried | How do you say, "Give me 8 VCPUs, but I don't care how you split them across NUMA nodes"? | |
| 20:17:43 | sean-k-mooney[m] | today if i have a guest with no numa toplogy and it cant fit on one numa node it will be spread. | |
| 20:17:51 | jaypipes | IMO, that third bullet should absolutely be amended to say "requesting granular request groups of the same resource means that the resulting candidates will be from different providers" | |
| 20:17:54 | dansmith | efried: if I just want multiple VFs and ensure they're on different PFs, but I don't care about any other reason, then VF=1,VF=1 means that, different from VF=2 | |
| 20:18:06 | dansmith | efried: VCPUS=8 | |
| 20:18:10 | sean-k-mooney[m] | if we say the non numbered resouce request must also be form one RP we cannot support that now | |
| 20:18:38 | efried | dansmith: VCPUS=8 will get you all 8 from the same RP. That's not even related to this discussion. | |
| 20:19:04 | jaypipes | sean-k-mooney[m]: the non-numbered request group specifically says "use_same_provider=False" | |
| 20:19:22 | dansmith | efried: how does VPUS=4,VCPUS=4 make it more flexible? | |
| 20:19:26 | dansmith | efried: that's not saying "do as you with" | |
| 20:19:28 | dansmith | *wish | |
| 20:19:51 | efried | dansmith: It doesn't. But VCPUS=1,VCPUS=1,VCPUS=1,VCPUS=1,VCPUS=1,VCPUS=1,VCPUS=1,VCPUS=1 does. | |
| 20:19:58 | sean-k-mooney[m] | dansmith: what about the case of all you severs have 2 numa node with 10 cores each and i want 16 cores but dont care about numa in my guest | |
| 20:20:00 | efried | dansmith: Now we can spread 'em any which way they fit. | |
| 20:20:04 | dansmith | efried: you can't be serious | |
| 20:20:32 | dansmith | efried: and if I want 32G of memory allocated anywhere? 32*24 query params? :) | |
| 20:20:44 | jaypipes | sean-k-mooney[m]: then you would request VCPU=16 | |
| 20:20:44 | sean-k-mooney[m] | jaypipes: so non granular can be form multiple RPs and granular resuest each request is guarteeed to be form differnt RPs | |
| 20:20:57 | efried | dansmith: I imagine step sizes come into play there | |
| 20:21:07 | jaypipes | sean-k-mooney[m]: yes. | |
| 20:21:12 | dansmith | efried: okay but that's still a damn lot of params for silly reasons | |
| 20:21:28 | dansmith | tbh, I'm kinda frustrated by this conversation at this stage in the game and I'm late leaving for something else | |
| 20:21:30 | efried | dansmith: How else do you ensure generic spreadability? Is that a silly reason? | |
| 20:21:44 | efried | Okay. Y'all have made your position clear. | |
| 20:21:50 | dansmith | so I shall bow out, but jaypipes I agree about that third bullet change, or at least putting a stake in the ground about needing to revisit it | |
| 20:22:02 | dansmith | back later | |
| 20:22:16 | jaypipes | efried: what is generic spreadability? is that like I can't believe it's not butter? | |
| 20:22:40 | efried | Oh, you better believe it. | |
| 20:22:43 | jaypipes | heh | |
| 20:24:49 | efried | jaypipes: It means, "I know I want 4 VCPUs. I don't care about NUMA affinity. I just want my instance." Some hosts have no NUMA (all VCPU on the compute RP). Some have two NUMA nodes, some have four. It's a fullish cloud. I sure would like it if I could land my instance, whether there's a host with 4 VCPUs in one NUMA node, or one with 3,1, or one with 2,1,1,0, etc. | |
| 20:25:35 | sean-k-mooney[m] | jaypipes: so just to confim. non granuarl resouce resutes can from from multiple RP. each Granular resouce request of the same resouce class is guarenteed to come form different RPs and Granular Resouce request can or cannot spread across multiple RP im assuming Cannot? | |
| 20:25:37 | jaypipes | efried: resources:VCPU=4 | |
| 20:25:40 | jaypipes | simply as that. | |
| 20:25:50 | efried | jaypipes: Then we're treating VCPU special. | |
| 20:25:58 | efried | jaypipes: Cause you definitely can't treat DISK_GB=1024 the same way. | |
| 20:26:32 | cdent | efried: are you saying in the case where the vcpu inventory is registered on the numa nested provider, or something else? | |
| 20:26:40 | jaypipes | sean-k-mooney[m]: a single granular request group of an amount of a resource class cannot spread that bucket across multiple providers, no. | |
| 20:26:44 | efried | sean-k-mooney[m]: As currently designed [1], separate request groups with the same resource class *may* or *may not* come from the same RP. | |
| 20:26:44 | efried | [1] http://specs.openstack.org/openstack/nova-specs/specs/rocky/approved/granular-resource-requests.html#semantics | |
| 20:26:55 | sean-k-mooney[m] | efried: that would be covered by just Resource:VCPU=4 | |
| 20:26:59 | efried | sean-k-mooney[m]: Oh, also what jaypipes says. | |
| 20:27:05 | efried | sean-k-mooney[m]: No - see above about DISK_GB. | |
| 20:27:06 | jaypipes | efried: how so? all of those resource providers have 4 VCPU available. | |
| 20:27:27 | sean-k-mooney[m] | efried: why? | |
| 20:27:27 | efried | jaypipes: No, 3,1 means "3 in NUMA node 0, 1 in NUMA node 1" etc. | |
| 20:28:01 | efried | sean-k-mooney[m]: If VCPU=4 means I can spread VCPU across multiple numa node RPs, then DISK_GB=1024 means I can spread... individual gigabytes? across multiple storage RPs. | |
| 20:28:08 | jaypipes | oh, in that case then no, no providers would be returned (since none have 4 VCPU available) | |
| 20:28:15 | jaypipes | efried: ^ | |
| 20:28:22 | jaypipes | efried: and that is A-OK in my book. | |
| 20:28:30 | efried | jaypipes: Exactly. I get NoValidHosts. But there *were* hosts with available procs. | |
| 20:28:40 | jaypipes | no there were not. | |
| 20:28:50 | jaypipes | efried: there were no resource providers that had 4 VCPU. | |
| 20:29:03 | efried | But there were *hosts* that had 4 VCPu. | |
| 20:29:20 | jaypipes | efried: the host isn't the provider of the VCPU in your scenario, though. | |
| 20:29:25 | efried | why not just say you can't have the same RC in different RPs then? | |
| 20:30:04 | sean-k-mooney[m] | jaypipes: well in his case there were 3cpus on 1 numa node an 1 on the second | |
| 20:30:08 | efried | jaypipes: But I didn't ask for my instance to land on a RP. I asked for it to land on a host. Which has a tree of RPs. But I don't know (and shouldn't care in this case) where the VCPUs are in that tree. | |
| 20:30:26 | jaypipes | sean-k-mooney[m]: exactly. there were no providers that had 4 VCPU available. | |
| 20:30:26 | sean-k-mooney[m] | but there was not host with 1 RP with 4 VCPUS | |
| 20:31:14 | efried | tbc, I'm agreeing that VCPU=4 should give you no hits in this case. | |
| 20:31:34 | efried | I'm saying we need a way to express a request that *does* land this instance. | |
| 20:31:51 | jaypipes | efried: I pretty specifically remember you telling me that my proposed "sum the inventories for like resource classes within a provider tree" was absolutely the wrong way to handle nested providers. | |
| 20:31:56 | sean-k-mooney[m] | jaypipes: right so today. before placement i can have a host with 2 socket each with 10 cores and i can boot a vm with no numa topology with 16 cores | |
| 20:32:02 | jaypipes | efried: and I'm saying I don't care about that. | |
| 20:32:14 | efried | jaypipes: Yes, exactly, because the DISK_GB case breaks it unequivocally. | |
| 20:32:14 | sean-k-mooney[m] | that would now break | |
| 20:32:26 | efried | ^^ this. | |
| 20:32:51 | jaypipes | I really don't care. | |
| 20:32:51 | efried | With the granular syntax as designed, we have a way to ask for this ^ that will work in *any* scenario. | |
| 20:33:10 | efried | namely: resources1=VCPU:1,...,resources16=VCPU:1 | |
| 20:33:13 | sean-k-mooney[m] | efried: well diskGB only breaks in some cases | |
| 20:33:24 | efried | I'll grant you that I don't want the admin/operator to have to say that. | |
| 20:33:28 | jaypipes | efried: that is just over-engineering IMHO. | |