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#openstack-nova - 2020-11-06
14:58:58 lyarwood gmann: ah did that bork the job on stable?
14:59:21 gmann gibi: lyarwood nova-ceph-multistore job is from victoria so backporting until victoria is needed
14:59:29 gmann lyarwood: yeah - https://zuul.opendev.org/t/openstack/build/bf932888821345c1955cda68226b1a87/
14:59:59 gmann tempest test which started running in nova-ceph-multistore on master as well on stable/victoria started running and needed this change on nova side
15:00:16 bauzas gibi: hah, that's maybe because the exception is not the same
15:00:52 bauzas ah no
15:00:54 bauzas nevermind
15:00:58 bauzas we log the exception
15:01:02 lyarwood gmann: ack I was going to look at that failure so thanks :)
15:01:11 bauzas hence the stracktrace
15:01:18 bauzas but that's horribly annoying
15:01:45 bauzas lyarwood: any ways for us to not getting a shitty number of exception lines anytime we use tox ?
15:01:58 gmann lyarwood: we added tempest test to copy-image for private images also (https://review.opendev.org/#/c/742546/23) which needed this policy to be open for everyone
15:02:03 bauzas because of rados and rbd missing
15:02:29 bauzas lyarwood: context being https://review.opendev.org/#/c/746873/4/nova/storage/rbd_utils.py
15:02:59 lyarwood gmann: ack
15:03:37 lyarwood bauzas: we could add some logic to skip the check based on an ENV var or something in test envs?
15:04:29 lyarwood bauzas: or we add them as test requirements?
15:04:36 lyarwood bauzas: even though they are virt driver specific
15:05:06 bauzas lyarwood: context is http://paste.openstack.org/show/799789/
15:05:19 lyarwood bauzas: yeah I;ve seen it
15:05:32 bauzas lyarwood: IMHO we should lazy load the modules
15:05:42 bauzas for rdb and rados
15:06:03 bauzas or making them needed for all *nova*
15:06:11 bauzas but, definitely, the former
15:06:19 bauzas if they are optional
15:06:29 bauzas (and only for a specific driver)
15:06:39 lyarwood bauzas: we lazy loaded before silently and it was a PITA to debug issues when they failed to import
15:06:46 lyarwood bauzas: assuming that's what you mean
15:07:07 lyarwood bauzas: could we not just add them as test deps?
15:07:16 bauzas lyarwood: then, lazy load them by creating the libvirt object
15:07:26 bauzas when initting
15:07:43 bauzas gibi: ^ to be honestly, I'm against https://review.opendev.org/#/c/746873/4/nova/storage/rbd_utils.py
15:08:07 bauzas because we create more problems for folks that don't use ceph than we fix the needed ones
15:09:07 openstackgerrit Merged openstack/nova master: zuul: Merge nova-evacuate into nova-multinode-live-migration https://review.opendev.org/755309
15:09:18 dansmith bauzas: me too, that seems crazy
15:10:36 dansmith surely we could check images_type and decide whether or not to explode there?
15:10:37 gibi bauzas, lyarwood, dansmith: can we move these import into one of the classes in the rbd_utils?
15:11:03 gibi dansmith: it is not exploding the driver, it is logging the import error
15:11:10 dansmith gibi: I think the point here was to make it explode before those get loaded, but that's not really okay, IMHO
15:11:13 bauzas gibi: the problem is that when using import directly, you *need* rdb
15:11:22 bauzas by any module
15:11:34 bauzas hence either lazy-loading it
15:11:55 bauzas or having other ways to support it like we did by telling none
15:12:06 dansmith yeah, go back to the old way and make something else check to see if the rbd import is None during early init, if we're in a dependent code path
15:12:16 bauzas by providing an exception you say "sorry, but you need it"
15:12:17 dansmith check config, or put it in a class we only load if we're using ceph
15:13:10 bauzas that too
15:13:19 bauzas there are multiple ways to make sure it's optional
15:16:29 openstack Launchpad bug 1903316 in OpenStack Compute (nova) "excessive logging of rbd and rados import errors" [Undecided,New]
15:16:29 gibi filed a bug https://bugs.launchpad.net/nova/+bug/1903316
15:19:43 gibi feel free to push a fix against it ^^
15:20:00 gibi if nobody then I might get to it at some point next week
15:22:04 bauzas gibi: I can try to fix it
15:22:37 bauzas but ideally, I'd love to understand the dynamics behind us logging this as an exception and what we wanted to fix previously
15:22:38 gibi ack, thanks
15:23:00 gibi I hope lyarwood can provide such context ^^
15:23:04 bauzas because I don't see a problem with lazy-loading at init time
15:23:38 bauzas we could even make nova-compute refuse to start if config option says "you should have it"
15:24:20 dansmith right
15:24:25 lyarwood bauzas: the context there is that we previously silently failed without logging any context about why the import failed.
15:24:30 dansmith or .. log the warning if configured and missing
15:24:54 lyarwood bauzas: we had a few downstream reports where this failed even with the modules in the container image etc.
15:25:25 lyarwood hmm I was sure there was a reason we couldn't check the config before doing this import
15:25:36 dansmith lyarwood: well before it was above the CONF,
15:25:55 dansmith lyarwood: but also, where we actually need it, check to see if the import is None, if so, try to import it again and log the exception there just to get the evidence
15:26:12 dansmith i.e. if rbd_utils.rbd is None: import rbd
15:27:04 lyarwood dansmith: yup understood
15:32:21 bauzas dansmith: lyarwood: honestly, I'm on the side we should fix the problem by making rdb and rados mandatory for the use of the right option, and make nova-compute hardstop if not
15:32:35 lyarwood bauzas: it already does
15:32:52 bauzas not in this module then, right?
15:33:06 lyarwood no, we just raise RuntimeError
15:33:17 bauzas when starting the compute service ?
15:33:41 lyarwood from this module that iirc stops the service eventually yes
15:33:44 lyarwood if rbd is used
15:34:26 bauzas the above try/catch is made at import time, not runtime
15:34:57 bauzas so unless we fail ungracefully there, we do check it at run time
15:35:06 lyarwood https://github.com/openstack/nova/blob/c0fe95fcc5aec99a83dd57093dc230ef67b36b39/nova/storage/rbd_utils.py#L139-L140
15:35:32 bauzas ack, run time
15:35:43 bauzas and when we create the instancez
15:35:56 bauzas which, I suspect, is made at init
15:36:34 bauzas lyarwood: okay, so indeed, we're all good, but why couldn't we just make the imports being made at run time just before this check ?
15:37:05 lyarwood I'm reworking this now
15:39:13 lyarwood the only issue now is that we need to ignore F401 as the imports aren't directly used in __init__
15:44:00 bauzas lyarwood: why ?
15:44:07 bauzas I'm confused
15:44:54 bauzas hah, so you have a rados object which isn't used
15:45:10 lyarwood no idea, must be the way the pep8 rule is written, rados is used within the class but it's also saying that the import isn't used
15:45:27 lyarwood both imports are listed as not used
15:45:40 lyarwood I've #noqa'd the lines anyway
15:45:50 bauzas lyarwood: use the importlib module
15:46:11 sean-k-mooney stephenfin: test
15:46:26 stephenfin HexChat didn't crash \o/
15:46:37 openstackgerrit Lee Yarwood proposed openstack/nova master: rbd: Only log import failures when the RbdDriver is used https://review.opendev.org/761762
15:46:39 sean-k-mooney you should still lookinto weechat
15:46:49 sean-k-mooney but glad its working
15:46:58 stephenfin meh, I live the GUI in a separate window
15:47:27 dansmith lyarwood: that's much better, IMHO
15:47:46 lyarwood yup not sure what I was thinking the first time round
15:47:53 sean-k-mooney stephenfin: by the way https://review.opendev.org/#/q/topic:bug/1895220+(status:open+OR+status:merged) are ready for you to review again

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