FYI, by default Openstack overcommit CPU 1:16, meaning it can host 16 times number of cores it possesses. As mentioned Alex, you can change it by enabling AggregateCoreFilter in nova.conf: scheduler_default_filters = <list of your filters, adding AggregateCoreFilter here>
and modifying the overcommit ratio by adding: cpu_allocation_ratio=1.0 Just a suggestion, think of isolating the host for the tenant that uses Hadoop so that it will not serve other applications. You have several filters at your disposal: AggregateInstanceExtraSpecsFilter IsolatedHostsFilter AggregateMultiTenancyIsolation Best regards, Toan ----- Original Message ----- From: "Alex Glikson" <glik...@il.ibm.com> To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev@lists.openstack.org> Sent: Tuesday, November 12, 2013 3:54:02 PM Subject: Re: [openstack-dev] [nova] Configure overcommit policy You can consider having a separate host aggregate for Hadoop, and use a combination of AggregateInstanceExtraSpecFilter (with a special flavor mapped to this host aggregate) and AggregateCoreFilter (overriding cpu_allocation_ratio for this host aggregate to be 1). Regards, Alex From: John Garbutt <j...@johngarbutt.com> To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev@lists.openstack.org>, Date: 12/11/2013 04:41 PM Subject: Re: [openstack-dev] [nova] Configure overcommit policy On 11 November 2013 12:04, Alexander Kuznetsov <akuznet...@mirantis.com> wrote: > Hi all, > > While studying Hadoop performance in a virtual environment, I found an > interesting problem with Nova scheduling. In OpenStack cluster, we have > overcommit policy, allowing to put on one compute more vms than resources > available for them. While it might be suitable for general types of > workload, this is definitely not the case for Hadoop clusters, which usually > consume 100% of system resources. > > Is there any way to tell Nova to schedule specific instances (the ones which > consume 100% of system resources) without overcommitting resources on > compute node? You could have a flavor with "no-overcommit" extra spec, and modify the over-commit calculation in the scheduler on that case, but I don't remember seeing that in there. John _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev _______________________________________________ OpenStack-dev mailing list OpenStack-dev@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
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