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#openstack-nova - 2022-05-26
11:11:21 sean-k-mooney if you can you could just group the loadbalnce request per AZ
11:12:01 kevko i am not sure if I understand
11:13:08 sean-k-mooney i was trying to recall if you needed to populate the server group in one go or coudl you make multiple server create request and resuse the same server group
11:13:12 sean-k-mooney i think its the latter
11:13:24 sean-k-mooney we have 2 or 3 ways to do anti afinity in nova
11:13:25 kevko you can set az in octavia ...an if you have az created from two datacentres ... server group and anti affinity will not work ..there is big chance that nova just schedule to two hosts ..but in same datacentre
11:13:35 sean-k-mooney and some requrie it all in one request and other allow it to be exteded.
11:14:11 sean-k-mooney kevko: right so ocativa could have an az anti affintiy policy in its api
11:14:18 kevko currently I think there is only one way to do it ... have 1 az from two hosts from two different datacentres ... but this is no way ..because we have hundreds of amphoraes :(
11:15:51 sean-k-mooney so what i would expect is you would creat at least 1 AZ per datacenter right
11:16:00 sean-k-mooney and then create a singel server group
11:16:05 sean-k-mooney with anti affintiy
11:16:32 sean-k-mooney and then in 2 differnet calls to nova create the vms for datacenter A and B
11:17:41 kevko it's not true i think
11:18:06 sean-k-mooney im describing the change you need to make to ocativa not how it works today
11:18:07 kevko anti-affinity works per host ...so there could be situation that in one datacentre instance will be scheduled on two hosts
11:18:21 sean-k-mooney kevko: correct
11:18:24 kevko yeah,
11:18:35 sean-k-mooney that is why you need ot use differnt AZ in the two diffenrt calls to nova
11:18:48 kevko octavia has availability_zone as one parameter in configuration
11:19:15 sean-k-mooney right if you want to supprot this you need to supprot this at the octavia api
11:19:15 kevko if this can be list and setup list of AZs where AZ is 2 hosts from two datacentres ... it will be work i think
11:19:18 sean-k-mooney not config driven
11:19:32 sean-k-mooney kevko: az in nova are nto the same as AZs in aws
11:19:41 sean-k-mooney the are jsut metadtaa on a a host aggreate.
11:20:01 sean-k-mooney there is not gurantee or expectiaon of a sperate falut domain
11:20:18 sean-k-mooney and conversily there is not guranteeor or expecation fo network connectivy between them
11:20:28 sean-k-mooney that is all determin by how you deploy your cloud
11:21:28 kevko yeah i know that it is only metadata defined for host (or how to say :P ...i really don't know how it looks like in deep)
11:21:48 sean-k-mooney its a strign defiend on a host aggareate
11:21:55 sean-k-mooney and then host are mapped to aggreates
11:23:33 kevko what about regions ?
11:23:38 kevko can be helpfull ?
11:23:42 sean-k-mooney the do not existin in nova
11:23:51 sean-k-mooney they are a keystone only construct
11:24:00 kevko yeah ... correct
11:24:03 kevko cells ?
11:24:24 sean-k-mooney cells are internal to nova
11:24:36 sean-k-mooney and not expsoed at the api to end users
11:24:47 sean-k-mooney they are a way to shared the db and message bus
11:24:52 kevko yeah i know ..
11:24:58 sean-k-mooney and are explictly not for fault tollerance
11:25:08 sean-k-mooney but they can kind fo help in a way
11:25:15 kevko so currently i don't have way how to deal with it
11:25:45 sean-k-mooney we coudl support az anti affintiy in nova
11:25:56 sean-k-mooney but we have rejected it in the past the last 2 times it came up
11:27:24 sean-k-mooney kevko: filters and weigher can be added out fo tree by the way
11:28:18 sean-k-mooney but all instnace will be mapped ot an az even if oenis not requested
11:28:49 sean-k-mooney so really if you want to use AZs to map to datacenters
11:29:19 sean-k-mooney then octavia need to accpet the AZ as an api parameter when creating loadblancers
11:29:48 sean-k-mooney and if you want ti to supprot spreaing loadbalncer between azs then it allso need to supprot doing that iself really
11:30:56 sean-k-mooney since AZ are not really visable to neutron by the way there is no guarentee at teh api level that a newton network can span azs
11:31:45 opendevreview sean mooney proposed openstack/os-vif master: [trivial] update job template to zed https://review.opendev.org/c/openstack/os-vif/+/843432
11:33:31 kevko why it was rejected ?
11:33:41 kevko this would be super usefull
11:42:11 sean-k-mooney https://github.com/openstack/nova/blob/master/doc/source/contributor/project-scope.rst#no-more-orchestration=
11:44:14 sean-k-mooney kevko: it came up on the ptg in the past i can see if there was a draft spec
11:44:44 sean-k-mooney kevko: https://review.opendev.org/c/openstack/nova-specs/+/756380
11:45:35 sean-k-mooney kevko: as i noted here https://review.opendev.org/c/openstack/nova-specs/+/756380/5#message-ba89445e7b2b033fe39f9bbd32a49271e4780e75=
11:45:49 sean-k-mooney doing this in a filter or weigher is far far too late
11:46:02 sean-k-mooney as the az is alreay asigned at that point
11:46:57 sean-k-mooney kevko: so the only way to do it today woudl be to have an AZ span both datacenters and then use somethign else to model the datacenters and provide anti afinity
11:47:22 kevko hmm
11:47:23 kevko understand
11:47:43 sean-k-mooney you coudl do that with metadata on host aggrats and then a weigher or filter that used that datacenter metadata
11:49:02 sean-k-mooney so 1 AZ that spans both datacheners 1 host aggreate per datacenter and a filter/weigher that used a datacenter tag on the host aggreate + server group infor to implment antiafinity
11:49:36 sean-k-mooney but its much simpelr to have 1 AZ per datacenter and have octaivr just schdule differnt loadbanceer to differnt AZs
11:49:59 kevko and this is not possible :/
11:50:00 sean-k-mooney its cleaner form an api level and more efficnt form a schdulign perspecitve
11:50:08 kevko because octavia has only one AZ to configure
11:50:19 sean-k-mooney right you woudl have to change octavia
11:50:39 sean-k-mooney so im suggestign you make a featur equest to octavia instead of nova
11:50:47 kevko yeah
11:50:52 kevko thank you !
11:50:58 kevko you are always replying ;-)
11:52:01 sean-k-mooney perhaps i reply too much on ocation
11:52:35 sean-k-mooney but when people have ligtimate usecase i try to help them find a solution
11:52:48 sean-k-mooney you do i just dont think the clean solution is in nova
11:53:29 sean-k-mooney for older release you coud do this as i descibe with an out of tree weigher/filter if you have 1 AZ and multiple host aggreates but thats messy for a number of reasons
11:56:11 kevko still thank you
12:16:34 opendevreview Miguel proposed openstack/nova master: Pin autopep8 to 1.5.5 in tox https://review.opendev.org/c/openstack/nova/+/843443
12:26:40 kevko sean-k-mooney last question : Can i import octaviaclient in my own custom nova filter ? :P
12:26:58 sean-k-mooney its your filter so :)
12:27:08 sean-k-mooney upstrem no
12:27:29 sean-k-mooney filters are not ment to make any db or api calls in general
12:27:49 sean-k-mooney filters run per host so we really dont want to do that on large clouds
12:28:32 kevko hmm, ok
12:28:53 kevko can I write filter which will check security group assigned ?
12:29:18 sean-k-mooney security groups? or server groups
12:31:28 kevko both :D
12:32:16 kevko i mean, if it is possible to check server groups it will be better, if no .. security group is same also
12:32:58 sean-k-mooney for server groups you can use the existin filter as a refernce
12:33:00 sean-k-mooney https://github.com/openstack/nova/blob/master/nova/scheduler/filters/affinity_filter.py#L82-L165=
12:33:09 sean-k-mooney but you cant add new policies
12:33:34 sean-k-mooney so you cant jsut add an AZ-anti-affinity policy
12:34:48 sean-k-mooney kevko: we dont have any example of the security gorups but if its in teh request spec then yes
12:35:15 kevko i will have to try
12:35:33 sean-k-mooney kevko: filters are passed 2 objects the hoststate object and a request spec object
12:35:35 sean-k-mooney https://github.com/openstack/nova/blob/master/nova/objects/request_spec.py#L42=
12:35:51 sean-k-mooney kevko: which has security groups https://github.com/openstack/nova/blob/master/nova/objects/request_spec.py#L98=

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