[Openstack-operators] [nova] Does anyone use the TypeAffinityFilter?

Matt Riedemann mriedemos at gmail.com
Fri Apr 7 00:34:47 UTC 2017


While working on trying to trim some RPC traffic between compute nodes 
and the scheduler [1] I came across the TypeAffinityFilter which relies 
on the instance.instance_type_id field, which is the original flavor.id 
(primary key) that the instance was created with on a given host. The 
idea being if I have an instance with type 20 on a host, then I can't 
schedule another host with type 20 on it.

The issue with this is that flavors can't be updated, they have to be 
deleted and recreated. This is why we're changing the flavor 
representation in the server response details in Pike [2] because the 
instance.instance_type_id can point to a flavor that no longer exists, 
so you can't look up the details on the flavor that was used to create a 
given instance via the API (you could figure it out in the database, but 
that's no fun).

So the big question is, does anyone use this filter and if so, have you 
already hit the issue described here and if so, how are you working 
around it? If no one is using it, I'd like to deprecate it.

[1] 
https://blueprints.launchpad.net/nova/+spec/put-host-manager-instance-info-on-a-diet
[2] 
https://specs.openstack.org/openstack/nova-specs/specs/pike/approved/instance-flavor-api.html

-- 

Thanks,

Matt



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