[openstack-dev] [nova] What is the goal of AggregateImagePropertiesIsolation filter?

Chris Friesen chris.friesen at windriver.com
Thu Oct 5 14:16:50 UTC 2017

On 10/05/2017 03:47 AM, Kekane, Abhishek wrote:

> So the question here is, what is the exact goal of
> AggregateImagePropertiesIsolation' scheduler filter: - Is it one of the following:-
> 1. Matching all metadata of host aggregate with image properties.
> 2. Matching image properties with host aggregate metadata.
> If we decide that actual goal of 'AggregateImagePropertiesIsolation' filter is
> as  pointed in #1, then a small correction is required to return False if image
> property is not present from the host aggregate metadata.

The name of the filter includes "Isolation", so I think the intent was to 
accomplish #1.  However, as you point out it only fails the filter if both the 
aggregate and the image have the same key but different values and so the 
isolation is imperfect.

At the same time we have the AggregateInstanceExtraSpecsFilter (which ensures 
that any keys in the flavor extra-specs must be present in the aggregate).

Since keys can be specified in either the flavor or the image, it could be 
confusing that the behaviour is different between these two filters.  At the 
same time we don't want to break existing users by modifying the behaviour of 
the existing filters.  Given this it might make sense to create a new filter 
which unifies the checks and behaves the same whether the key is specified in 
the image or the flavor, with some way to toggle whether we want strict 
isolation or not (so that we can ensure only "special" flavors/images are 
allowed to use aggregates with specific limited resources).


More information about the OpenStack-dev mailing list