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#openstack-nova - 2019-03-19
10:37:04 gibi cdent: especially that we "need to fix" even if we don't know what is the use case
10:37:08 cdent that's the other half of the story: "we're using this cloud as a home for our pets"
10:38:01 sean-k-mooney cdent: of cource clouds and nice and fluffy places for our pets to live with totally no sharp edges
10:38:19 cdent made by magical open source bunnies!
10:38:50 gibi sean-k-mooney: no edges?! :) we want EDGE in the cloud :D
10:39:34 sean-k-mooney gibi: hehe ture but hopefully said edges wont be sharp :)
10:39:49 gibi we need fluffy edges!
10:40:35 sean-k-mooney new goal for summit. get "fluffy edges" into someones marketing deck
10:44:06 cdent fluffy edges sounds like a pretty good term for dynamically scalable edge nodes
10:48:41 kashyap aspiers: "Not consumed by anything" is okay so long as it (a) helps with clarity; (b) makes way for future patches to cherry-pick it for a particular use case
10:55:21 aspiers kashyap: yeah but needs to be testable still!
10:56:14 kashyap aspiers: Agreed :-) Don't let this block you.
11:03:37 openstackgerrit Matthew Booth proposed openstack/nova master: Eventlet monkey patching should be as early as possible https://review.openstack.org/626952
11:09:54 kashyap mdbooth_: When you get a moment, since we always return a non-None 'disk_cachemode' here: https://review.openstack.org/#/c/641981/10/nova/virt/libvirt/driver.py@443
11:10:12 kashyap mdbooth_: Are you implying to remove the check there?
11:10:35 mdbooth kashyap: No, that comment was wrt the release note
11:10:50 mdbooth Because we never return non-None there, we never use the qemu default
11:10:57 mdbooth So to the qemu default is irrelevant
11:11:07 kashyap Ah, guessed as much.
11:11:13 kashyap You wrote it in reference to the help text
11:11:18 kashyap Okay, elided the irrelevant bit.
11:11:19 kashyap Thanks!
11:11:31 mdbooth s/release note/docs/
11:16:53 openstackgerrit Gorka Eguileor proposed openstack/nova master: Fix unnecessary locking when connecting volumes https://review.openstack.org/614190
11:22:35 openstackgerrit Kashyap Chamarthy proposed openstack/nova master: libvirt: Use 'writeback' QEMU cache mode when 'none' is not viable https://review.openstack.org/641981
11:22:35 openstackgerrit Kashyap Chamarthy proposed openstack/nova master: libvirt: vzstorage: Use 'writeback' QEMU cache mode https://review.openstack.org/643376
11:22:36 openstackgerrit Kashyap Chamarthy proposed openstack/nova master: libvirt: smbfs: Use 'writeback' QEMU cache mode https://review.openstack.org/643377
11:23:17 sean-k-mooney kashyap: you are not enableing writeback by defualt when none is not available are you?
11:24:01 kashyap sean-k-mooney: That's exactly what it's doing; please read the commit message. I spent 3 hours writing it.
11:24:04 kashyap https://review.openstack.org/#/c/641981/
11:24:22 sean-k-mooney kashyap: if none is not an option we shoudl default to the safet alternitive either directsync or writethrough and only use writeback if there is no other option
11:24:27 kashyap FWIW, : I ran the patch by QEMU Block Layer maintainer over an e-mail thread.
11:24:38 kashyap sean-k-mooney: No, that is wrong. See the commit message and the comment in the code, again.
11:24:44 sean-k-mooney i just saw the ping. i had not opened it yet
11:28:25 sean-k-mooney kashyap: i had under stood that writback did not honer guest fush commands. is that not the case?
11:28:40 sean-k-mooney if it does the ok
11:28:44 sean-k-mooney *then
11:32:58 kashyap sean-k-mooney: It does honour it
11:33:02 kashyap sean-k-mooney: Also see: http://git.openstack.org/cgit/openstack/nova/commit/?h=master&id=e7b64eaad8
11:33:06 sean-k-mooney ok ya looking at the docs it does
11:33:30 kashyap Nod
11:34:09 sean-k-mooney i had tought there was still an edgecase with virtio scsi not informing the guest os that it was in writeback mode and that this only worked with virtio-block but maybe not
11:34:18 sean-k-mooney i could be tinking of discard instead of flush
11:36:36 sean-k-mooney kashyap: anywya i trust your and the qemu maintiners knoladge of this better then my own. its been a while since i dug into the cahce modes in any detail
11:44:16 sean-k-mooney kashyap: ah i found the ceph note i was missremembering. when using caching with RBD you expcitly have to use writeback cache mode not that you sould not use cach=writeback. http://docs.ceph.com/docs/master/rbd/qemu-rbd/#running-qemu-with-rbd the last time i looked into this was determing the correct way to use qemu safely with ceph storage with caching which at the time was virio-scsi for
11:44:18 sean-k-mooney discard/trim support + writeback cache if i wanted safe caching
12:31:14 kashyap sean-k-mooney: Just back from lunch
12:32:08 kashyap sean-k-mooney: Yep, I also suggest you think about the cache modes in terms of the three booleans each mode toggles.
12:32:19 kashyap It allows better reasoning of the concept
12:32:49 kashyap sean-k-mooney: (Yeah, that Ceph thing is accounted for by our own NOTE in the Nova config help docs.)
12:35:24 openstackgerrit Adam Spiers proposed openstack/nova master: Move libvirt calculation of machine type to utils.py https://review.openstack.org/644554
12:39:56 sean-k-mooney kashyap: well i generally use boot from volume or rbd image driver so i generally have not needed to resonable about cachemodes for qemu/raw image backend
12:40:31 kashyap Noted; was only saying as a future note :-)
12:41:22 sean-k-mooney the only time i tend to have local images is devstack :) but yes i look this up about once a year when i need to but its one of those things that i generaly dont rememebr off the top of my head unfortunetly
12:45:29 kashyap Nod; /me does a yearly "refresher course" on QEMU's caching behaviour...because damned if I could ever remember the details
12:48:51 mdbooth There seems to be a problem with the openstack-tox-docs job
12:48:57 mdbooth It's failed for me twice in a row now.
12:49:12 mdbooth http://logs.openstack.org/52/626952/7/check/openstack-tox-docs/d4bea1d/job-output.txt.gz#_2019-03-19_11_13_38_088828
12:49:41 openstackgerrit Kashyap Chamarthy proposed openstack/nova master: libvirt: Rework 'EBUSY' (SIGKILL) error handling code path https://review.openstack.org/639091
12:52:14 aspiers kashyap: trying to split getDomCaps out, but another issue is that the design decision to use a nested dict of dicts was heavily influenced by SEV https://review.openstack.org/#/c/633855/11/nova/virt/libvirt/host.py@706
12:52:47 aspiers mdbooth: that would be nice :)
12:52:50 mdbooth Or even better, a 'only recheck this single job'
12:52:56 kashyap mdbooth: Sounds like a nice request for the fine folks on #openstack-infra
12:53:00 frickler kashyap: seems this is your real error, probably related to your patch http://logs.openstack.org/52/626952/7/check/openstack-tox-docs/d4bea1d/job-output.txt.gz#_2019-03-19_11_13_31_488145
12:53:31 kashyap frickler: You mean mdbooth's ^
12:53:42 aspiers kashyap: so either the preliminary getDomCaps patch prematurely references SEV before introducing support for it, or it makes a design decision without explaining it
12:53:48 frickler kashyap: yes, mangled up scrollback, sorry
12:53:53 kashyap aspiers: Reading ...
12:54:18 mdbooth frickler: Ah, thanks!
12:54:30 mdbooth That was a super-unhelpful error message!
12:55:15 mdbooth frickler: Out of curiosity, what grep-fu did you use to find that?
12:56:11 mdbooth NM, I suppose it's just above the other error.
12:56:18 frickler mdbooth: none, I just know that failure to copy "../doc/build" mostly results from the docs build having failed earlier. so I scrolled back a bit more to find the other error
12:57:48 frickler mdbooth: another way to approach this is to look at the ara report, where you can easily spot that not only the docs-post job failed, but also the main run, which most of the time has the more interesting errors http://logs.openstack.org/52/626952/7/check/openstack-tox-docs/d4bea1d/ara-report/
12:58:29 mriedem dansmith: i'm assuming you want to just mark this as won't fix or something https://bugs.launchpad.net/nova/+bug/1820851
12:58:30 openstack Launchpad bug 1820851 in OpenStack Compute (nova) "Please do cell mapping without periodic task or active admin involvment" [Wishlist,Opinion]
13:00:08 mdbooth frickler: That's awesome. Thanks.
13:04:07 kashyap aspiers: Hmm. Still thinking on the nested dictionary of arch–machine type mapping ...
13:04:17 aspiers ok
13:04:22 kashyap aspiers: Can you put what you just wrote in the review, please?
13:04:27 kashyap As a "consciousness strem"
13:04:29 kashyap s/strem/stream/
13:14:41 openstackgerrit Boris Bobrov proposed openstack/nova master: Extract SEV-specific bits on host detection https://review.openstack.org/636334
13:14:41 openstackgerrit Boris Bobrov proposed openstack/nova master: Fix memtune parameters according to libvirt docs https://review.openstack.org/636301
13:14:42 openstackgerrit Boris Bobrov proposed openstack/nova master: Add configs for AMD SEV https://review.openstack.org/636318
13:14:42 openstackgerrit Boris Bobrov proposed openstack/nova master: Add iommu driver to devices https://review.openstack.org/644564
13:14:43 openstackgerrit Boris Bobrov proposed openstack/nova master: [wip] Driver changes for sev https://review.openstack.org/644565
13:16:44 sean-k-mooney kashyap: nested dict of arch machine type mappings? in the nova.conf or image. i dont think i makes sense in the image and we basically aready have that in the nova.conf
13:17:34 kashyap sean-k-mooney: For more context, check out the "returns" here: https://review.openstack.org/#/c/633855/11/nova/virt/libvirt/host.py@706
13:17:49 kashyap sean-k-mooney: The context is to separate out the getDomainCapabilities() method from that file
13:18:26 mdbooth Hmm. Unless I can differentiate between workloads which are simply loading Nova classes to gather metadata and workloads which actually plan to execute Nova code, I'm going to have to remove the monkey patching asserts :/
13:18:36 mdbooth Although the former really shouldn't be monkey patching at all
13:18:48 mdbooth But they always have been, so I guess it doesn't matter in practise
13:19:13 sean-k-mooney kashyap will a machine type ever be suppoted by two archs? i dont think so right. so it could jsut be a dict of machine_type to capablities
13:20:44 sean-k-mooney if your going with the nested structure however i would strongly think of make really OVO however instead of dicts of dicts of capablity dicts
13:22:03 kashyap sean-k-mooney: So far we have AArch64 that has 'virt' machine type -- now there is upstream QEMU talk to introduce something similar for x86_64
13:22:40 kashyap sean-k-mooney: Please note your point on the change pointed earlier.
13:22:47 sean-k-mooney kashyap: ah and the capablitys fo the virt machine type would be different for aarch64 vs x86
13:23:03 kashyap Exactly
13:25:14 mriedem yay this is old https://github.com/openstack/nova/blob/master/nova/scheduler/client/report.py#L1549-L1552

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