[Openstack] Confused about GroupAntiAffinityFilter and GroupAffinityFilter

Simon Pasquier simon.pasquier at bull.net
Mon Sep 2 09:19:58 UTC 2013


I tried to play with GroupAntiAffinityFilter and GroupAffinityFilter 
filters but it looks like the documentation is misleading [1]. Looking 
more precisely at the commits that introduced these filters [2][3], my 
assumption is that to use these filters, one would boot a first instance 
with '--hint group=foo' and the scheduler would update the 
instance_system_metadata table with {key:'group',value:'foo}. Then when 
starting other instances with the same hint option, the scheduler would 
filter the candidate hosts by querying the instance_system_metadata table.

Still this doesn't work for me. In my tests with 
GroupAntiAffinityFilter, I have 3 compute nodes, each running one 
instance not in any group. Then when I launch a VM specifying a group 
hint, the scheduler fails to find a valid host because 
GroupAntiAffinityFilter filter returns 0 host.

Could someone provide some guidance on how to use this filter?


[2] https://review.openstack.org/#/c/21070/
[3] https://review.openstack.org/#/c/35788/

Simon Pasquier
Software Engineer
Bull, Architect of an Open World
Phone: + 33 4 76 29 71 49

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