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#openstack-nova - 2017-03-16
08:51:45 bauzas I could write a spec
08:52:20 bauzas so it would mean a behavioural change, but post that microversion, it shouldn't be possible to change an AZ name
08:52:46 alexey_weyl bauzas: Does it sound as a reasonable use case from your side?
08:53:25 alexey_weyl bauzas: didn't quite understoud your last sentence.
08:54:30 bauzas alexey_weyl: lemme rephrase
08:55:02 bauzas alexey_weyl: since the AZ information is just an aggregate metadata that is user-facing, we already have the ID you need
08:55:19 gmann alexey_weyl: "when a user changes the AZ name" user you mean admin/operator right
08:55:27 bauzas changing that metadata value for that specific key is source of confusion, so I'm not in favor of accepting that
08:55:29 alexey_weyl bauzas: of course
08:55:54 alexey_weyl bauzas: so, you have that id already? can we get from somewhere?
08:56:08 bauzas it's just an aggregate...
08:59:13 alexey_weyl bauzas: don't quite understand. what can I do?
09:00:13 bauzas alexey_weyl: do you know https://docs.openstack.org/developer/nova/aggregates.html#availability-zones-azs ?
09:00:20 gmann alexey_weyl: we have id for aggregate not for AZ
09:01:41 alexey_weyl gmann: I am familiar with the ID in the aggregate host.
09:02:25 bauzas alexey_weyl: https://developer.openstack.org/api-ref/compute/?expanded=show-aggregate-details-detail tells you that availability_zone is just a specific metadata key for an aggregate
09:03:01 bauzas alexey_weyl: we're leaking the DB PK on the API unfortunately, but we added an aggregate UUID since 2.41
09:03:22 alexey_weyl gmann: I understand.
09:04:10 bauzas https://docs.openstack.org/developer/nova/aggregates.html#availability-zones-azs is explaining that AZs are just a conceptual object that Nova doesn't deal with
09:10:03 alexey_weyl I see
09:10:14 alexey_weyl bauzas: I see
09:10:27 alexey_weyl bauzas: Then I have please another question
09:11:00 alexey_weyl bauzas: I saw that when i change the AZ name or the aggregated host name I dont receive any update event on the oslo messaging bus
09:11:10 alexey_weyl bauzas: how can i receive those updates?
09:11:19 bauzas you mean a notification ?
09:11:25 alexey_weyl correct
09:11:33 bauzas because it's an admin operation
09:11:42 bauzas so you are supposed to know what you do
09:12:17 alexey_weyl bauzas: but vitrage needs to get a notification of such a change.
09:12:36 bauzas I'd rather name it a callback...
09:12:47 alexey_weyl bauzas: ok
09:13:04 bauzas alexey_weyl: well, you can propose to add some new notifications
09:13:16 alexey_weyl bauzas: but still, when even an admin changes something we need to get some update that such a thing was done, how can we get it?
09:13:23 alexey_weyl i see
09:13:33 bauzas gibi: do you know if we need a spec for adding notifications? my guts say yes
09:14:11 bauzas johnthetubaguy: ^
09:17:52 gibi bauzas: so far we went with specless bp for searchlight related additions
09:18:22 gibi Kevin_Zheng: ping, I'm here now
09:19:12 Kevin_Zheng gibi: Ah, Hi, I was going to ask something for notification, but I got it sorted out :)
09:19:12 bauzas gibi: good to know
09:19:24 gibi Kevin_Zheng: OK :)
09:19:32 bauzas gibi: I thought the notification object was somehow needing a consensus before writing the implementation, but okat
09:20:06 bauzas gibi: here, we are talking of sending notifications about aggregate modifications
09:20:09 gibi bauzas, alexey_weyl: yeah, if this is a new non trivial object then I agree that a spec for the data model is a good thing to have
09:20:29 bauzas gibi: do we notify some aggregate-related objects ?
09:20:32 bauzas already I mean
09:20:32 openstackgerrit jichenjc proposed openstack/nova master: Prevent delete cell0 in nova-manage command https://review.openstack.org/433476
09:20:59 gibi bauzas: yeah, aggregate.create and .delete are both already transformed to versioned format
09:21:13 bauzas so we already emit those ?
09:21:16 gibi bauzas: aggregate.add_host and remove_host are in the pipe
09:21:22 gibi bauzas: yes
09:21:36 bauzas gibi: okay, that's what alexey_weyl was looking for
09:21:56 bauzas he would like to subscribe on aggregate metadata change
09:21:59 gibi bauzas, alexey_weyl: here is the data modell https://github.com/openstack/nova/blob/master/nova/notifications/objects/aggregate.py
09:22:24 bauzas gibi: perfect
09:22:43 gibi bauzas, alexey_weyl: I think metadata is already part of the notification
09:22:47 bauzas so alexey_weyl just needs to have the aggregate update to emit
09:22:53 bauzas gibi: yup
09:23:25 bauzas gibi: is there already a bp for tracking this ?
09:23:50 bauzas AFAICS, a specless BP should be enough given we already have the notification model
09:23:53 alexey_weyl gibi: bauzas: I am not quite familiar with all the internals of nova.
09:24:06 gibi bauzas: the aggregate ones are part of the notification transformation bp
09:24:13 gibi bauzas: as legacy had those as well
09:24:37 bauzas gibi: yeah, but that blueprint is not intended to add *more* notifications, just transform the existing, correct?
09:24:38 gibi bauzas: the metadata update part is something that is not transformed yet
09:24:59 gibi bauzas: we have metadata update legacy notification https://github.com/openstack/nova/blob/master/nova/objects/aggregate.py#L442
09:25:01 bauzas gibi: lemme verify if we emit legacy notifications
09:25:07 bauzas ah-ah !
09:25:26 gibi bauzas: so we have to just transform that
09:25:30 bauzas gibi: so alexey_weyl would just need to contribute to the transformation bp
09:25:44 gibi bauzas, alexey_weyl: it seems so, yes.
09:25:48 bauzas perfect
09:25:57 alexey_weyl bauzas: gibi: I didn't quite understood all what you said. can you please summerize that for me? what do I need to do?
09:26:02 bauzas alexey_weyl: so, your problem is solved from a nova perspective
09:26:12 gibi alexey_weyl: sure
09:26:21 bauzas alexey_weyl: as gibi said, we already emit notifications on aggregate update
09:26:26 bauzas https://github.com/openstack/nova/blob/master/nova/objects/aggregate.py#L442
09:26:47 bauzas alexey_weyl: the thing is, we emit the information on a non-versioned dict
09:27:04 gibi alexey_weyl: we are creating a new notification interface for nova, to have a proper interface. these are called versioned notifications.
09:27:13 bauzas alexey_weyl: so gibi is the lead for transforming our legacy payloads into a richer format
09:27:17 alexey_weyl bauzas: gibi: I am listening to all of the notifications from nova and I didn't see any notification from nova when I changed the name of the AZ or the Aggregated host
09:27:40 gibi alexey_weyl: do you listen to notifications topic?
09:27:45 alexey_weyl yes
09:28:01 alexey_weyl we have added to notification topics a vitrage_notificcation
09:28:02 bauzas https://github.com/openstack/nova/blob/master/nova/objects/aggregate.py#L443 is the notification name
09:28:10 gibi alexey_weyl: hm, you should get aggregate.updatemetadata.end notification
09:28:11 alexey_weyl and thus we can receive all the data
09:28:17 openstackgerrit Béla Vancsics proposed openstack/nova master: Reduce code complexity - libvirt/config.py https://review.openstack.org/359879
09:28:41 alexey_weyl bauzas: gibi: I will check it again just to make sure.
09:28:44 bauzas in theory, that notification has a payload including the metadata that changed https://github.com/openstack/nova/blob/master/nova/objects/aggregate.py#L423
09:29:01 gibi alexey_weyl: if you not see that after updating metadata of an aggregate then we have some bug
09:29:22 gibi alexey_weyl: I will try to verify that as well
09:30:05 gibi alexey_weyl: btw, do vitrage plans to move from the legacy nova notifications to the versioned ones?
09:31:48 bauzas gibi: AFAICS, if you do the WSGI action on os-aggregates to set_metadata, you call the Aggregate object method that emits the legacy notification
09:31:58 bauzas https://github.com/openstack/nova/blob/master/nova/api/openstack/compute/aggregates.py#L196
09:32:34 bauzas and https://github.com/openstack/nova/blob/master/nova/compute/api.py#L4490
09:32:50 alexey_weyl gibi: I have to admit that this is the first time I hear about that, so I will need to check it out. But if this is something that all the projects have then vitrage will have to use such the new notifications
09:33:31 gibi alexey_weyl: we are in the process to define and implement the new interface so it is the good time to chime in from consumer side
09:33:44 gibi bauzas: that is my understanding of the code as well
09:34:17 gibi bauzas: but if alexey_weyl does not see the notification then there is something we don't see

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