AggregateImagePropertiesIsolation filter return unwanted compute nodes

[Md Nadeem]

The host_passes() method return True for the compute node which do not have the matching key-value meta data with the glance-image property.

Eg: Say if we want to filter only those compute node which has os='lx' metadata set in the Aggregate property. To achieve the goal we need to set os='lx' in glance image-property and created an Aggregate with os='lx' metadata and attached the target compute nodes to it.

However AggregateImagePropertiesIsolation filter also return all other host in which "os" as a key is not defined along with matching target host. like it also choose another compute node that attached to some Aggregate whose metadata node container "os" key, it may contain some other metadata like "cpu=4".

So as of now, to get desire result, we need to set os='lx' to the Aggregate that attached to the target compute node and need to add all other node to an Aggregate that must have the "os" as a key with some other values, like os='win'.

>>https://github.com/openstack/nova/blob/c9eb9530314d047f5013941ebcfd5ef0192a9dc3/nova/scheduler/filters/aggregate_image_properties_isolation.py#L63

[Takashi Natsume (natsume-takashi)]

There is the following blueprint.

https://blueprints.launchpad.net/nova/+spec/strict-isolation-of-group-of-hosts-for-image-and-flavor
https://review.openstack.org/#/c/381912/

[Matt Riedemann (mriedem)]

https://blueprints.launchpad.net/nova/+spec/placement-req-filter-forbidden-aggregates is related.