On 2016-03-03 12:50 PM, Silence Dogood wrote: > We did some early affinity work and discovered some interesting problems > with affinity and scheduling. =/ by default openstack used to ( may > still ) deploy nodes across hosts evenly. > > Personally, I think this is a bad approach. Most cloud providers stack > across a couple racks at a time filling them then moving to the next. > This allows older equipment to age out instances more easily for removal > / replacement. > > The problem then is, if you have super large capacity instances they can > never be deployed once you've got enough tiny instances deployed across > the environment. So now you are fighting with the scheduler to ensure > you have deployment targets for specific instance types ( not very > elastic / ephemeral ). goes back to the wave scheduling model being > superior. > > Anyways we had the braindead idea of locking whole physical nodes out > from the scheduler for a super ( full node ) instance type. And I > suppose you could do this with AZs or regions if you really needed to. > But, it's not a great approach. > > I would say that you almost need a wave style scheduler to do this sort > of affinity work. >
You can already do it with the RAMWeigher using the ram_weight_multiplier config: Multiplier used for weighing ram. Negative numbers mean to stack vs spread. Default is 1.0 which means spread. -- Mathieu _______________________________________________ OpenStack-operators mailing list OpenStack-operators@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators