<html><body><div style="font-family: times new roman, new york, times, serif; font-size: 12pt; color: #000000"><div><span style="font-family: arial, helvetica, sans-serif;">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:</span></div><div><span style="font-family: arial, helvetica, sans-serif;"> scheduler_default_filters = <list of your filters, adding AggregateCoreFilter here></span><br></div><div><span style="font-family: arial, helvetica, sans-serif;"><br></span></div><div><span style="font-family: arial, helvetica, sans-serif;">and modifying the overcommit ratio by adding:</span></div><div><span style="font-family: arial, helvetica, sans-serif;"> cpu_allocation_ratio=1.0</span></div><div><span style="font-family: arial, helvetica, sans-serif;"><br></span></div><div><span style="font-family: arial, helvetica, sans-serif;">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:</span></div><div><span style="font-family: arial, helvetica, sans-serif;"> AggregateInstanceExtraSpecsFilter</span></div><div><span style="font-family: arial, helvetica, sans-serif;"> IsolatedHostsFilter</span></div><div><span style="font-family: arial, helvetica, sans-serif;"> AggregateMultiTenancyIsolation</span></div><div><span style="font-family: arial, helvetica, sans-serif;"><br></span></div><div><span style="font-family: arial, helvetica, sans-serif;">Best regards,</span></div><div><span style="font-family: arial, helvetica, sans-serif;"><br></span></div><div><span style="font-family: arial, helvetica, sans-serif;">Toan</span></div><div><span style="font-family: Verdana, Geneva, sans-serif; font-size: 13px;"><br></span></div><hr id="zwchr"><div style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>From: </b>"Alex Glikson" <GLIKSON@il.ibm.com><br><b>To: </b>"OpenStack Development Mailing List (not for usage questions)" <openstack-dev@lists.openstack.org><br><b>Sent: </b>Tuesday, November 12, 2013 3:54:02 PM<br><b>Subject: </b>Re: [openstack-dev] [nova] Configure overcommit policy<br><div><br></div><span size="2" face="sans-serif" data-mce-style="font-family: sans-serif; font-size: small;" style="font-family: sans-serif; font-size: small;">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).</span>
<br>
<br><span size="2" face="sans-serif" data-mce-style="font-family: sans-serif; font-size: small;" style="font-family: sans-serif; font-size: small;">Regards,</span>
<br><span size="2" face="sans-serif" data-mce-style="font-family: sans-serif; font-size: small;" style="font-family: sans-serif; font-size: small;">Alex</span>
<br>
<br>
<br>
<br>
<br><span size="1" color="#5f5f5f" face="sans-serif" data-mce-style="color: #5f5f5f; font-family: sans-serif; font-size: xx-small;" style="color: #5f5f5f; font-family: sans-serif; font-size: xx-small;">From:
</span><span size="1" face="sans-serif" data-mce-style="font-family: sans-serif; font-size: xx-small;" style="font-family: sans-serif; font-size: xx-small;">John Garbutt <john@johngarbutt.com></span>
<br><span size="1" color="#5f5f5f" face="sans-serif" data-mce-style="color: #5f5f5f; font-family: sans-serif; font-size: xx-small;" style="color: #5f5f5f; font-family: sans-serif; font-size: xx-small;">To:
</span><span size="1" face="sans-serif" data-mce-style="font-family: sans-serif; font-size: xx-small;" style="font-family: sans-serif; font-size: xx-small;">"OpenStack Development
Mailing List (not for usage questions)" <openstack-dev@lists.openstack.org>,
</span>
<br><span size="1" color="#5f5f5f" face="sans-serif" data-mce-style="color: #5f5f5f; font-family: sans-serif; font-size: xx-small;" style="color: #5f5f5f; font-family: sans-serif; font-size: xx-small;">Date:
</span><span size="1" face="sans-serif" data-mce-style="font-family: sans-serif; font-size: xx-small;" style="font-family: sans-serif; font-size: xx-small;">12/11/2013 04:41 PM</span>
<br><span size="1" color="#5f5f5f" face="sans-serif" data-mce-style="color: #5f5f5f; font-family: sans-serif; font-size: xx-small;" style="color: #5f5f5f; font-family: sans-serif; font-size: xx-small;">Subject:
</span><span size="1" face="sans-serif" data-mce-style="font-family: sans-serif; font-size: xx-small;" style="font-family: sans-serif; font-size: xx-small;">Re: [openstack-dev]
[nova] Configure overcommit policy</span>
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<hr noshade="">
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<br><tt><span size="2" data-mce-style="font-size: small;" style="font-size: small;">On 11 November 2013 12:04, Alexander Kuznetsov <akuznetsov@mirantis.com>
wrote:<br>
> Hi all,<br>
><br>
> While studying Hadoop performance in a virtual environment, I found
an<br>
> interesting problem with Nova scheduling. In OpenStack cluster, we
have<br>
> overcommit policy, allowing to put on one compute more vms than resources<br>
> available for them. While it might be suitable for general types of<br>
> workload, this is definitely not the case for Hadoop clusters, which
usually<br>
> consume 100% of system resources.<br>
><br>
> Is there any way to tell Nova to schedule specific instances (the
ones which<br>
> consume 100% of system resources) without overcommitting resources
on<br>
> compute node?<br>
<br>
You could have a flavor with "no-overcommit" extra spec, and
modify<br>
the over-commit calculation in the scheduler on that case, but I don't<br>
remember seeing that in there.<br>
<br>
John<br>
<br>
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<br>
</span></tt>
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