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#openstack-nova - 2025-07-02
12:59:32 sean-k-mooney so that is not somthign they can use to detect if its oepnstack
12:59:59 sean-k-mooney it will work for libvirt with qemu but its not genrelaly correct to do
13:00:28 fungi right, all the rationale and debate as to available options is still locked up in a private lp bug
13:02:24 sean-k-mooney so to me the behaivor it hasd to reach out to the link local adress was the correct behavior and not a security issue
13:02:50 sean-k-mooney you can disable datasouce via the cloud init config in yoru image if you wanted too
13:05:22 sean-k-mooney im not ok with https://review.opendev.org/c/openstack/nova/+/953732 by the way
13:05:51 sean-k-mooney fungi: i guess that is why that was being rasised earlier in the week
13:41:44 sean-k-mooney fungi: by the way the dmi info when it is provided to vms is also configuabel via the downstream distobution https://github.com/openstack/nova/blob/2c19c07d5e29ca5445fa6dd45a6117542951714c/nova/version.py#L49-L63
13:44:28 sean-k-mooney i dont hink we have used this historically downstream
13:44:37 sean-k-mooney but its a thing that can be configured
13:47:44 gibi I'm sorry there was a botched rebased in the bottom of the series...
13:47:53 opendevreview Balazs Gibizer proposed openstack/nova master: Use futurist for _get_default_green_pool() https://review.opendev.org/c/openstack/nova/+/948072
13:47:54 opendevreview Balazs Gibizer proposed openstack/nova master: Add spawn_on https://review.opendev.org/c/openstack/nova/+/948079
13:47:54 opendevreview Balazs Gibizer proposed openstack/nova master: Replace utils.spawn_n with spawn https://review.opendev.org/c/openstack/nova/+/948076
13:47:55 opendevreview Balazs Gibizer proposed openstack/nova master: Move ConductorManager to use spawn_on https://review.opendev.org/c/openstack/nova/+/948187
13:47:55 opendevreview Balazs Gibizer proposed openstack/nova master: Move ComputeManager to use spawn_on https://review.opendev.org/c/openstack/nova/+/948186
13:47:56 opendevreview Balazs Gibizer proposed openstack/nova master: Rename DEFAULT_GREEN_POOL to DEFAULT_EXECUTOR https://review.opendev.org/c/openstack/nova/+/948086
13:47:56 opendevreview Balazs Gibizer proposed openstack/nova master: Make nova.utils.pass_context private https://review.opendev.org/c/openstack/nova/+/948188
13:47:57 opendevreview Balazs Gibizer proposed openstack/nova master: Print ThreadPool statistics https://review.opendev.org/c/openstack/nova/+/948340
13:47:57 opendevreview Balazs Gibizer proposed openstack/nova master: Make the default executor configurable https://review.opendev.org/c/openstack/nova/+/948087
13:47:59 opendevreview Balazs Gibizer proposed openstack/nova master: Allow services to start with threading https://review.opendev.org/c/openstack/nova/+/948311
13:47:59 opendevreview Balazs Gibizer proposed openstack/nova master: Document native threading mode and tuneables https://review.opendev.org/c/openstack/nova/+/949364
13:48:01 opendevreview Balazs Gibizer proposed openstack/nova master: Do not yield in threading mode https://review.opendev.org/c/openstack/nova/+/950994
13:48:01 opendevreview Balazs Gibizer proposed openstack/nova master: Run nova-next with n-sch in threading mode https://review.opendev.org/c/openstack/nova/+/948450
13:48:03 opendevreview Balazs Gibizer proposed openstack/nova master: Warn on long task wait time for executor https://review.opendev.org/c/openstack/nova/+/952666
13:48:03 opendevreview Balazs Gibizer proposed openstack/nova master: Run nova-api and -metadata in threaded mode https://review.opendev.org/c/openstack/nova/+/951957
13:48:05 opendevreview Balazs Gibizer proposed openstack/nova master: Run unit test with threading mode https://review.opendev.org/c/openstack/nova/+/953475
13:48:05 opendevreview Balazs Gibizer proposed openstack/nova master: Allow to start unit test without eventlet https://review.opendev.org/c/openstack/nova/+/953436
13:48:07 opendevreview Balazs Gibizer proposed openstack/nova master: [test]RPC using threading or eventlet selectively https://review.opendev.org/c/openstack/nova/+/953815
13:49:53 opendevreview Balazs Gibizer proposed openstack/nova master: FUP: Translate scatter-gather to futurist https://review.opendev.org/c/openstack/nova/+/953338
14:31:14 opendevreview Kamil Sambor proposed openstack/nova master: Replace eventlet.event.Event with threading.Event https://review.opendev.org/c/openstack/nova/+/949754
14:32:52 gibi eventlet sycn https://meet.google.com/bcy-uqoz-hje?authuser=0
14:53:03 fungi sean-k-mooney: thanks, yeah revisiting my recollections of the original bug, it's that cloud-init is guessing whether it's booting in an openstack environment based on the dmi data, but that only works for qemu virtual machines on x86, so on e.g. arm cloud-init can't decide whether it's safe to assume the metadata source is legitimate or potentially spoofed by some attacker
14:53:05 fungi because it doesn't know whether it's in an openstack cloud
14:56:24 sean-k-mooney right but you can contol that by the cloud-init config in the guest when you build the image
14:56:39 sean-k-mooney adn the expect behiovr is to enumerate all data souces that are enabled in the image
14:57:02 sean-k-mooney so to me removign the enumeration is fundementaly breakign how this was inteded to work
14:57:15 sean-k-mooney no i think they are jsut chagnign there defaults in there config
14:57:19 sean-k-mooney rather then entirly removing it
14:58:21 sean-k-mooney i.e. if you expiclty customise an image and enable the openstack data souce adn upload it to glance
14:58:35 sean-k-mooney you can still use ti with vmware or lxc or ironic
15:01:14 sean-k-mooney i would not be surpised if some distros decide to revert back when buidling there cloud images
15:01:46 sean-k-mooney fungi: glean just uses config drive right, ye never implemented the metadata rest api?
15:07:27 fungi i think so, we prefer dhcp/slaac+ra but if the cloud needs to set network configuration through metadata then we rely on glean to pull that from the configdrive because our experience with network metadata sources has been bad
15:21:49 gmaan stephenfin: RE v2.0, thanks for updates. +W on the deprecation way.
15:22:18 stephenfin ta
15:23:18 gmaan gibi: yeah, that was my main concern on v2.0 direct removal as it was not marked as deprecated or not supported. at least giving deprecation phase to users (if any) can come forward if they need it for some more time and why not using v2.1
15:31:18 opendevreview ribaudr proposed openstack/nova-specs master: Enable memfd support for shared memory backing https://review.opendev.org/c/openstack/nova-specs/+/951689
15:32:17 gibi gmaan: cool, I agree that we need a deprecation first
15:32:57 Uggla sean-k-mooney, if you can have a look at 951689: Enable memfd support for shared memory backing | https://review.opendev.org/c/openstack/nova-specs/+/951689 let me know if I manage to capture all you inputs.
15:33:14 Uggla sean-k-mooney, no urgency on that one.
15:33:36 gibi fyi, Sree while verifying PCI in Placement caught a nice, long standing bug in our pci tracker https://bugs.launchpad.net/nova/+bug/2115729
15:34:56 opendevreview Merged openstack/nova-specs master: Deprecate v2.0 API https://review.opendev.org/c/openstack/nova-specs/+/951949
15:48:30 Uggla gibi, I have seen this bug yesterday. kudos to Sree. I guess I can triage it as a valid one ?
15:48:47 gibi I did the triage now that I found the root cause
15:49:03 gibi I will push a fix in 30 mins...
15:50:50 Uggla gibi, faster than light !
15:54:37 gibi this is a typical bug where finding the root cause is the hard thing, fixing it is the easy
16:05:02 ratailor gmaan, could you please provide your feedback on https://review.opendev.org/c/openstack/nova-specs/+/929780/ my replies ?
16:08:33 opendevreview Rajesh Tailor proposed openstack/nova-specs master: Show finish_time field in instance action show https://review.opendev.org/c/openstack/nova-specs/+/929780
16:09:05 ratailor sean-k-mooney, gibi could you please also review ^^ as tomorrow is last date for FF.
16:12:16 opendevreview Balazs Gibizer proposed openstack/nova master: Reproduce that only half of the PCI devs are removed https://review.opendev.org/c/openstack/nova/+/953971
16:12:17 opendevreview Balazs Gibizer proposed openstack/nova master: Fix pci_tracker.save to delete all removed devs https://review.opendev.org/c/openstack/nova/+/953972
16:12:46 gmaan ratailor: sure, will check today
16:13:20 ratailor gmaan, Thanks!
18:29:46 opendevreview Alexey Stupnikov proposed openstack/nova master: Use updated_at to purge shadow_instance_extra https://review.opendev.org/c/openstack/nova/+/953984
18:33:58 opendevreview Alexey Stupnikov proposed openstack/nova master: Use updated_at to purge shadow_instance_extra https://review.opendev.org/c/openstack/nova/+/953984
18:41:46 sean-k-mooney gibi: bauzas Uggla did ye look at my verion of the iothreads spec by the wayhttps://review.opendev.org/c/openstack/nova-specs/+/953940/2/specs/2025.2/approved/dynamic-vm-iothreads.rst
18:42:02 sean-k-mooney we are unlikely to merge either by tomorrow but i fell like my version is closer
18:50:55 opendevreview Merged openstack/nova-specs master: Add flavor-search-by-name spec https://review.opendev.org/c/openstack/nova-specs/+/940440
19:28:45 Uggla combine the two.
19:28:45 Uggla sean-k-mooney, yep I have quickly looked at it. Tbh I think from technical point of view It looks great. I'm just annoyed about how masahito feels about it. I'd like a kind of co authoring and make sure his need is fulfill by the spec too. I will discuss with him tomorrow, because I'd like to explain, the goal is not to overwrite his spec but
19:31:24 mikal hard coded zeroconf IP address on any of the clouds I can think of.
19:31:24 mikal fungi: my general recollection of this decade old coversation aligns with what sean-k-mooney said. Config drive v2 was always meant as a stop gap until everyone was using the metadata service. It really only existed at all because it was copied from AWS. I'm confused by your x86 address detection comments because the metadata service just uses a
19:32:07 mikal fungi: certainly a lot of the warts in config drive (like it originally not being able to be updated, although I think maybe that's fixed now) were because it was seen as a temporary thing.
19:35:41 fungi mikal: i was mis-remembering the bug, looking at the cloud-init commit it's "nova detection" really. they want to only contact the metadata server address for discovery if run in an openstack (or ec2) cloud, so are checking dmi to determine if it's safe to do so, but that check is only viable on x86
19:36:51 fungi so when it comes to booting generic non-x86 distro cloud images with cloud-init included, the recommendation is to rely on configdrive instead
19:37:06 mikal Honestly most of that DMI stuff is a bit dumb. That data exists in metadata, why do we ram it into two places one of which doesn't work on other architectures?
19:38:06 fungi yeah, and so if nova didn't do that even on x86, then cloud-init would really just recommend distros go back to making openstack-specific images so they could set the override in the kernel command-line or an embedded conffile
19:38:40 fungi (or suggest always using configdrive maybe)
19:38:42 mikal I'm not here to hate on config drive. My point is more that its outlived its expected life, had some weird implementation choices because of the time it was done in, and probably needs some love if its really here forever.
19:39:14 opendevreview Brett Holman proposed openstack/nova master: Add DMI data to non-x86 architectures https://review.opendev.org/c/openstack/nova/+/953989
19:39:35 mikal Like for example it execs a command line to build the ISO image, solely because the only library we could find at the time to do it nicely was GPL and we refused to use GPL dependencies.
19:39:37 fungi agreed, it has challenges, for example the earlier change at the start of this discussion about using virtio for cdrom devices by default, because debian doesn't include ahci drivers in their genericcloud kernel configs
19:40:07 mikal FAT config drives should work too? IIRC it doesn't _have_ to be a CDROM, it just defaults to that?
19:40:12 mikal Its been a long time.
19:40:52 fungi it probably could be any kind of block device, i think it was virtual cd by convention so not sure if that assumption is baked into places (e.g. in cloud-init)
19:42:11 fungi granted, forcing a different device type is still going to be a custom image property on upload or some similar override, if it's not nova's default
19:51:47 mikal So cloud-init will only probe for a couple of things to match -- device ID matters (config2) and type. The probing code only looks for CDROMs or FAT formatted disks IIRC.
19:53:10 mikal Honestly, most of the people I know who really use metadata use it as a poor man's replacement for Nova not having some sort of mature out of band agent thing. They really want AWS SSM agent or equivalent -- https://docs.aws.amazon.com/systems-manager/latest/userguide/ssm-agent.html.
19:54:17 mikal We could do the same with either a custom agent or the qemu agent (although the qemu agent has some pretty big limitations), that bit isn't too hard. The hard bit is marshalling the requests into the instance. That likely involves some sort of per-instance queue that Nova doesn't have right now.
19:58:38 fungi yeah, an actual communication channel from host to guest at least, if not bi-directional
19:59:04 mikal Yeah, specifically one which doesn't not require networking to be configured and working.
19:59:38 mikal I worked for a training startup for a bit... We did all sorts of contortions to rescue VMs when students messed up their networking. This would have made it so much easier.
19:59:49 fungi a fifo-like proc interface in the kernel or something would be amazing
20:00:29 fungi and/or pseudofiles like device drivers tend to expose
20:00:32 mikal So qemu-agent uses a unix domain socket on the outside and virtio-serial on the inside and speaks JSON blobs, which is a bit terrible. Serial means only one talker at a time.
20:01:39 fungi though at boot time, one talker in the guest is generally sufficient?
20:01:48 mikal ShakenFist does this with a unix domain socket on the outside and virtio-vsock on the inside, and speaks protobufs. That's actually really cool if I don't say so myself because the in-guest agent can just run a socket server like you're used to and serve N requests at the same time because virtio-vsock does all the multiplexing for you.
20:01:59 fungi or maybe not these days, with the advent of parallel boot processing

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