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#openstack-nova - 2017-03-16
08:18:20 gmann alex_xu: yea, actually it came up on https://review.openstack.org/#/c/431740/4 i am not sure why they cannot use show_extension for all, let me check with author
08:20:07 Kevin_Zheng ping gibi
08:20:44 alexey_weyl can anyone please help me
08:20:50 alexey_weyl I wanted to ask please why there is no id for the availability-zone?
08:21:43 alex_xu gmann: emm....strange
08:22:48 gmann alex_xu: yea from user point of view show_extension will be same, its only internal implementation which does extra checks on policies
08:24:06 gmann alexey_weyl: for AZ we have only name
08:24:12 alex_xu gmann: but the discovery policy is something we deprecated?
08:24:21 alex_xu why people still depend on it
08:24:46 gmann alexey_weyl: i mean its always different name so id not needed
08:25:32 gmann alex_xu: you mean extensions right or discovery policy also we deprecated ?
08:27:48 bauzas good morning Nova
08:28:03 alex_xu gmann: i think the discovery policy
08:28:33 alex_xu gmann: https://review.openstack.org/#/c/427872/ johnthetubaguy propose to remove in it in that spec
08:28:53 alex_xu gmann: not suer whether we have note to say it already deprecated
08:29:30 gmann alex_xu: yea, i was thinking the same. i think we do not have as there was no good way to deprecate policy...
08:29:45 openstackgerrit jichenjc proposed openstack/nova master: Prevent delete cell0 in nova-manage command https://review.openstack.org/433476
08:29:56 alexey_weyl gmann: that is correct, but if i change the name of the availability zone then vitrage don't know of which zone it was originally
08:30:46 alexey_weyl gmann: meanning, Vitrage don't know what zone was changed, because the previous name doesn't appear.
08:30:48 alex_xu gmann: not like config opt
08:34:11 gmann alex_xu: yea
08:34:51 gmann alexey_weyl: humm, yea name change, changes the AZ completely
08:35:47 alexey_weyl gmann: so how can Vitrage know which availability zone was changed besides storing a cache of all of the different availability zones?
08:35:52 gmann alexey_weyl: but you can get the old AZ from GET server
08:36:39 gmann alexey_weyl: i mean servers booted with AZ will be having the same
08:39:30 alexey_weyl gmann: do you think I can open a bug that we would like the availability zone to have an ID?
08:40:30 alexey_weyl gmann: but still when Vitrage is doing get all availability zones it won't know what AZ was changed.
08:40:33 openstackgerrit Béla Vancsics proposed openstack/nova master: Reduce code complexity - libvirt/config.py https://review.openstack.org/359879
08:40:53 bauzas FWIW, I'm personnally opposed to accept the AZ changing its name unless there are no left instances in there
08:41:03 bauzas it's a source of confusion
08:41:27 gmann bauzas: yea me too, alexey_weyl is it much required use case?
08:41:36 bauzas creating an AZ is possibly one of the most important things to make sure
08:42:05 bauzas for example, you can default instances to have an AZ by modifying the config to name the default AZ
08:42:21 gmann AZ is something managed with name so changing name is all if you do not want to deal with old one
08:42:39 bauzas it's also an end-user UX
08:42:46 bauzas meaning that users see the AZs
08:42:57 gmann yea
08:43:07 bauzas when you want to modify a name, then you trample all your users
08:45:42 alexey_weyl bauzas: But shouldn't the AZs have and ID. like for every entity in the Database, that its properties are changed, so we will know whos data was changed by the ID.
08:46:14 alexey_weyl bauzas: gmann: another question, how can I receive update events of the AZ on oslo messaging bus?
08:46:19 bauzas alexey_weyl: AZs are just an aggregate metadata
08:46:51 bauzas alexey_weyl: it's not a nova specific object, neither persisted like you think
08:47:47 alexey_weyl bauzas: Let me explain to you our use case in Vitrage, and lets see what can be done.
08:49:24 alexey_weyl bauzas: In Vitrage we have many entities of different projects in Openstack and physical entities as well that Vitrage monitors and shows to the user and to the system as well so all the alarms and the root cause alarms in the system can be shown.
08:50:04 alexey_weyl bauzas: Thus, when a user changes the AZ name, it needs to be reflected in the Vitrage entity graph that has the AZ vertex in it.
08:50:40 openstackgerrit Béla Vancsics proposed openstack/nova master: Reduce code complexity - libvirt/config.py https://review.openstack.org/359879
08:50:46 alexey_weyl bauzas: When vitrage receive the updated data from nova about the AZs in nova it doesn't know which AZ was changed or deleted or what has happened.
08:51:10 alexey_weyl bauzas: Thus if the AZ will have and ID Vitrage will know what AZ was changed or deleted.
08:51:24 bauzas alexey_weyl: I'm personnally in favor of not accepting to change the AZ if there are already some instances
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

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