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<p class="MsoNormal">Hi all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">As of now in the current master AggregateImagePropertiesIsolation filter returns True even if image property is not present in the host aggregate metadata.<o:p></o:p></p>
<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal">Example:<o:p></o:p></p>
<p class="MsoNormal">(1) Set below required config options in nova.conf under 'filter_scheduler' section:<o:p></o:p></p>
<p class="MsoNormal">aggregate_image_properties_isolation_namespace is set to 'os'<o:p></o:p></p>
<p class="MsoNormal">aggregate_image_properties_isolation_separator is set to '_'<o:p></o:p></p>
<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal">1) add Host Aggregate with custom metadata "os_windows":<o:p></o:p></p>
<p class="MsoNormal">+----+-----------+-------------------+--------------+------------------------+<o:p></o:p></p>
<p class="MsoNormal">| Id | Name | Availability Zone | Hosts | Metadata |<o:p></o:p></p>
<p class="MsoNormal">+----+-----------+-------------------+--------------+------------------------+<o:p></o:p></p>
<p class="MsoNormal">| 1 | win-agg | - | 'controller' | 'os_type=os_windows' |<o:p></o:p></p>
<p class="MsoNormal">+----+-----------+-------------------+--------------+------------------------+<o:p></o:p></p>
<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal">2) Add AggregateImagePropertiesIsolation filter to 'scheduler_default_filters'<o:p></o:p></p>
<p class="MsoNormal">scheduler_default_filters = RetryFilter,AggregateImagePropertiesIsolation,AvailabilityZoneFilter,RamFilter,DiskFilter,ComputeFilter,...<o:p></o:p></p>
<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal">Scenario A: Image property is present in the host aggregate metadata<o:p></o:p></p>
<p class="MsoNormal">(a) Create image with property os_type=os_windows<o:p></o:p></p>
<p class="MsoNormal">(b) Boot VM using image created in point 1.<o:p></o:p></p>
<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal">In this case, 'AggregateImagePropertiesIsolation' will return True and instance will be successfully created in host present in aggregate 'win-aggregate'.<o:p></o:p></p>
<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal">Scenario B: Image property is not present in the host aggregate metadata<o:p></o:p></p>
<p class="MsoNormal">(a) Create image with property os=rhel<o:p></o:p></p>
<p class="MsoNormal">(b) Boot VM using image created in point 1.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In this case, AggregateImagePropertiesIsolation shouldn't select any host from "win-aggregate" host aggregate group as it doesn't contains 'os_type=os_rhel". But as per the current implementation [1], it is checking if image property key
"os_type" is present or not. Even if it's not there, it is returning True from this filter, thus allowing to boot instance on the host from "win-aggregate" host aggregate group.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">So the question here is, what is the exact goal of AggregateImagePropertiesIsolation' scheduler filter: - Is it one of the following:-<o:p></o:p></p>
<p class="MsoNormal">1. Matching all metadata of host aggregate with image properties.<o:p></o:p></p>
<p class="MsoNormal">2. Matching image properties with host aggregate metadata.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">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.<o:p></o:p></p>
<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal">Please let me know your opinion about the same.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">[1] https://github.com/openstack/nova/blob/master/nova/scheduler/filters/aggregate_image_properties_isolation.py#L53<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thank you,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Abhishek Kekane<o:p></o:p></p>
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