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When I'm trying to boot instances on a specific host (sleepy) by issuing:

nova boot --image mybucket/image.manifest.xml --flavor m1.tiny --key_name mykey --hint force_hosts=sleepy test-vm

my VMs always seem to start on a random host instead on the one I targeted. Does anybody know why that might be? I'm using Essex and the simple scheduler.

My user is admin (I sourced /var/lib/nova/novarc), I also have --allow_admin_api=true in my nova.conf file. The only mention of filter in my /var/log/nova-scheduler.log is

u'filter_properties': {u'scheduler_hints': {u'force_hosts': u'sleepy'}}.

This file also says u'_context_is_admin': True and u'_context_roles': [u'admin']

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up vote 1 down vote accepted

Your problem is you are using the simple scheduler, which does not support filters or hints; it only "implements a naive scheduler that tries to find the least loaded host (i.e., implements a "spread-first" algorithm)."

You need to be using the Filter Scheduler, either as the primary or as the compute sub-scheduler.

See Chapter 11: Scheduling of the Openstack manual for more information.

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I can't try out your solution at the moment, but after looking at the code it seems to me you are right - the filter scheduler, unlike the simple scheduler, calls the host_manager to filter hosts and only inside host_manager did I see usage of the force_hosts option. I will try it out in a couple of days and give some more feedback. – metakermit Aug 15 '12 at 11:55
No, unfortunately, the issue seems to be appearing with the filter scheduler as well. I have compute_scheduler_driver=nova.scheduler.filter_scheduler.FilterScheduler in my nova.conf and am still having the same problem. – metakermit Oct 4 '12 at 14:38

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