nova/releasenotes/notes/deprecate-TypeAffinityFilter-465c47a6b2a7bd77.yaml
Matt Riedemann 46ba7e8df5 Deprecate TypeAffinityFilter
This deprecates the TypeAffinityFilter. This filter, which
is really an anti-affinity filter for flavors, attempts to
ensure that no two flavors show up on the same host. However,
to do this it relies on the flavors.id primary key, which is
subject to "change" if/when the admin deletes and recreates a
flavor (this is how Horizon allows you to 'edit' a flavor).
When you do that, you have a new flavor with a new id primary
key and the filter will not know the difference. So you could
really end up with more than one m1.large instance on the
same host, which defeats the purpose of the filter.

This filter is also problematic for
blueprint put-host-manager-instance-info-on-a-diet because in
that blueprint we want to stop sending full instance objects
over RPC from all compute services to the scheduler just to
track affinity and anti-affinity. All we really need for the
ServerGroupAffinityFilter and ServerGroupAntiAffinityFilter
is the list of instance uuids on a host, not the full object.
If we can get rid of TypeAffinityFilter, we can change the
compute<>scheduler RPC calls to just pass the list of instance
uuids for update_instance_info rather than sending an InstanceList.

Change-Id: I660e0316b11afcad65c0fe7bd167ddcec9239a8b
2017-05-27 10:15:25 +00:00

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YAML

---
deprecations:
- |
TypeAffinityFilter is deprecated for removal in the
17.0.0 Queens release. There is no replacement planned for this
filter. It is fundamentally flawed in that it relies on the
``flavors.id`` primary key and if a flavor "changed", i.e. deleted
and re-created with new values, it will result in this filter
thinking it is a different flavor, thus breaking the usefulness of
this filter.