| Posted | Nick | Remark | |
|---|---|---|---|
| #openstack-nova - 2017-07-18 | |||
| 15:53:30 | jaypipes | dtantsur: looking at that devstack custom RCs patch now... | |
| 15:53:41 | mriedem | melwitt: do we count instances atomically across multiple cells? | |
| 15:53:42 | dtantsur | thanks! | |
| 15:53:52 | gibi | jaypipes: looking... | |
| 15:53:55 | mriedem | melwitt: don't we have a separate session for each cell db? | |
| 15:53:59 | melwitt | mriedem: no, each cell is atomic | |
| 15:54:17 | dansmith | mriedem: we can't count atomically across cells | |
| 15:55:03 | mriedem | right, | |
| 15:55:14 | mriedem | so my point is, saying we can't do it atomically b/c of the api db is kind of a cop out | |
| 15:55:25 | mriedem | since we can't do it atomically for multiple cells either | |
| 15:55:29 | dansmith | well, | |
| 15:55:34 | dansmith | but the cells don't overlap with each other | |
| 15:55:40 | mriedem | true, yes | |
| 15:55:41 | dansmith | the api db and the cell dbs do overlap | |
| 15:55:44 | mriedem | the race window is a problem | |
| 15:55:47 | mriedem | between build requests and instances | |
| 15:56:12 | mriedem | again, i don't think i'm advocating trying to account for build requests in flight at the same time as counting the instances | |
| 15:56:21 | mriedem | i just want to make sure we thought about it and are ok with it | |
| 15:57:54 | jaypipes | dtantsur: answered. | |
| 15:58:09 | melwitt | mriedem: yeah, I mean, I was thinking ideally we should count them because they are parts of instances | |
| 15:58:46 | dtantsur | jaypipes: thanks! I wonder if we should enroll nodes after nova-compute is started then | |
| 15:58:58 | dtantsur | jaypipes: to better emulate how things work in actual production | |
| 15:59:00 | dtantsur | wdyt? | |
| 15:59:03 | mriedem | the "for x in 5; nova boot --min-count 20...." worries me | |
| 15:59:39 | jaypipes | dtantsur: well, they automatically get enrolled when the nova-compute node starts, but it doesn't look like that has run by the time the test tries to boot an instance. | |
| 16:00:04 | dtantsur | this is suspicious.. okay, thanks for the hints. I'll take a deeper look tomorrow | |
| 16:00:17 | jaypipes | dtantsur: looks to be just a simple ordering issue to me. | |
| 16:00:37 | jaypipes | dtantsur: I will look further into it as well and leave comments on the patch. | |
| 16:00:45 | dtantsur | thanks :) | |
| 16:14:55 | melwitt | mriedem: yeah. the bad thing about counting both is it could get too much usage if you say, count build requests and then count instances, some of those instances could have been build requests a split second ago, and then you get too much usage after you add them together | |
| 16:17:16 | gibi | jaypipes: here is the log http://paste.openstack.org/show/615753/ | |
| 16:20:21 | jaypipes | gibi: excellent, that helps a lot, thank you! | |
| 16:20:40 | jaypipes | gibi: the usage information isn't being returned for rp 1 for some reason. | |
| 16:21:37 | gibi | jaypipes: rp 1 is the compute provider? | |
| 16:21:48 | jaypipes | gibi: yeah | |
| 16:22:11 | melwitt | mriedem, dansmith: apparently sqlalchemy supports two-phase commit. do you think that's something we could use to get atomic across databases? http://docs.sqlalchemy.org/en/latest/orm/session_transaction.html#enabling-two-phase-commit | |
| 16:22:41 | jaypipes | melwitt: I wouldn't go that route. It's a pain in the ass, frankly. | |
| 16:23:05 | dansmith | not worth it, IMHO | |
| 16:24:00 | melwitt | hm, okay | |
| 16:24:10 | jaypipes | gibi: what's the result of SELECT * FROM inventories WHERE resource_provider_id = 1? | |
| 16:26:08 | melwitt | dansmith: I guess the rechecking quota stuff takes care of the gap between build requests and instances ... in that after creating the instance objects we check quota again. so maybe that's how not counting build requests can be fine (if someone is configured to be strict about quotas) | |
| 16:26:26 | dansmith | melwitt: yep | |
| 16:26:32 | melwitt | mriedem: ^ | |
| 16:26:56 | melwitt | whew, good. | |
| 16:27:33 | openstackgerrit | Merged openstack/nova master: [placement] fix 500 error when allocating to bad class https://review.openstack.org/484162 | |
| 16:27:40 | mriedem | melwitt: you mean the recheck performed in conductor? | |
| 16:27:48 | melwitt | mriedem: yeah | |
| 16:28:05 | gibi | jaypipes: http://paste.openstack.org/show/615755/ | |
| 16:28:33 | mriedem | yeah, my point earlier today was the difference in ux - before counting qoutas, you'd go overquota and fail the api with a 403 and no instances are created - after we if we catch it in conductor, the instances all get put into ERROR state and you have to clean them up | |
| 16:28:38 | mriedem | melwitt: not the end of the world, but it's different | |
| 16:29:32 | dansmith | now I'm forgetting, | |
| 16:29:45 | dansmith | but the first check is done in api, and the extra if configured check is in conductor, right? | |
| 16:29:57 | melwitt | dansmith: yes | |
| 16:29:58 | mriedem | yeah | |
| 16:30:03 | mriedem | we recheck for cells v1 in the api | |
| 16:30:06 | dansmith | right, so the ux change is only across the boundary | |
| 16:30:07 | mriedem | b/c that's where the instances are created | |
| 16:30:10 | mriedem | but...cellsv1 | |
| 16:30:11 | dansmith | which isn't that big of a deal, IMHO | |
| 16:30:41 | mriedem | it's not the end of the world, | |
| 16:30:41 | dansmith | quota is so leaky right now, | |
| 16:30:57 | mriedem | i only ever worry about the NFV robots hammering things in unexpected ways | |
| 16:30:58 | jaypipes | gibi: are you calling GET /allocation_candidates?resources=CUSTOM_MAGIC:512 or are you including VCPU and MEMORY_MB in the request as well? | |
| 16:31:08 | dansmith | we could have added another check to the current stuff where we decided to fail your instance because we healed the quota and the numbers no longer work out | |
| 16:31:32 | openstackgerrit | Merged openstack/nova master: Support tag instances when boot(4/4) https://review.openstack.org/469800 | |
| 16:31:38 | melwitt | every quota.reserve() call heals before checking | |
| 16:31:54 | mriedem | heal == refresh()? | |
| 16:31:55 | melwitt | er, it heals YOUR quota. but not others in your project. so you could still be screwed | |
| 16:32:26 | dansmith | melwitt: it doesn't heal negative things, right? | |
| 16:32:42 | dansmith | like when things get all out of whack and require admin and nova-manage intervention | |
| 16:32:45 | dansmith | that's what I meant | |
| 16:32:49 | gibi | jaypipes: I'm calling just MAGIC:512 first, that results in HTTP 500 then I call with both MAGIC and VCPU + MEMORY that goes through but results in an empty response | |
| 16:32:51 | melwitt | I don't think it stores negative usage | |
| 16:33:23 | jaypipes | gibi: can you paste the logs from the second request for VCPU, MAGIC and MEMORY_MB? | |
| 16:33:24 | melwitt | yeah, you need nova-manage when not all users in the cloud are active in booting instances and their quota is out of whack and affecting those who are active | |
| 16:33:41 | dansmith | melwitt: that's all I mean.. when the current broke-ass shit gets broke-ass | |
| 16:33:47 | melwitt | yeah | |
| 16:34:11 | mriedem | can i borrow $5 for some quota? | |
| 16:34:39 | dansmith | mriedem: you're just going to spend it on booze, so no | |
| 16:35:14 | mriedem | s/itches/scratches/ | |
| 16:35:16 | mriedem | sorry | |
| 16:35:51 | melwitt | heh. I was thinking about that. lots of people where I grew up did say you itch an itch. which never made sense to me | |
| 16:36:38 | gibi | jaypipes: that generate a lot less log: http://paste.openstack.org/show/615756/ | |
| 16:37:31 | jaypipes | dansmith, mriedem: so, here's an interesting little wrinkle... if I request *only* resources that are provided by a sharing provider, and don't request any resources that say, a compute node, would have, there's no way to return an AllocationRequest that would include the compute node resource provider UUID. | |
| 16:38:00 | dansmith | why would you | |
| 16:38:01 | dansmith | ? | |
| 16:38:14 | dansmith | if you don't request any resources from the compute node... you don't get a compute node | |
| 16:39:12 | jaypipes | dansmith: but the compute node is a target because the shared resource is shared with it. | |
| 16:39:40 | dansmith | can you give a concrete example? | |
| 16:39:55 | dansmith | because shared disk should be allocate-able without a compute node if you don't care about CPU/RAM right? | |
| 16:40:51 | jaypipes | dansmith: I actually can't think of a concrete use-case here. | |
| 16:40:52 | mriedem | if you request things that don't result in compute nodes, you just get NoValidHost | |
| 16:40:59 | mriedem | which is fine for nova scheduler right? | |
| 16:41:04 | dansmith | mriedem: from scheduler, but not from placement | |
| 16:41:06 | mriedem | we can't build you a server on a ceph pool alone | |
| 16:41:09 | mriedem | dansmith: sure | |
| 16:41:19 | jaypipes | mriedem: well, technically you get a KeyError right now :) but, even then, I'm not sure. | |
| 16:41:27 | dansmith | right, but it should be fine for cinder to ask for an allocation against a storage provider with nothing else | |
| 16:41:34 | mriedem | yeah so let's fix the KeyError in placement | |
| 16:41:39 | mriedem | right | |