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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"> Please advise me whether the following scenario requires changes to nova scheduler or can be handled with existing scheduling mechanisms.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I have a type of PCIe device (not necessarily a NIC or HBA). The device can be configured with a set of user-defined resources – say A, B, C. Each resource can be shared between a limited number of VMs -- say A can be shared among 4 VMs,
B among 8, etc. A VM image may request the need for a specific list of features, say A and B. Then I want to place the VM on a host according to these criteria:<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>If there are hosts with a PCIe device that already has A and B configured, and has a free instance each of A and B, the VM must be placed on one of those hosts.<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo2"><![if !supportLists]><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>Otherwise, find a host with this PCIe device that can be configured with one instance each of A and B.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It is not clear that this can be handled through 3<sup>rd</sup> party metadata. Suppose we create host aggregates with properties like “resource=A” and “resource=B”, and also associate properties like “resource=A” with VM images. (A and
B are UUIDs representing user-defined resources.) <span style="color:#1F497D">Perhaps
</span>Nova scheduler can match the properties to select host aggregates that have all properties that the VM requires. However:<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo4"><![if !supportLists]><span style="mso-list:Ignore">a.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>This would not be dynamic (i.e. track the free instances of each resource), and<o:p></o:p></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l1 level1 lfo4"><![if !supportLists]><span style="mso-list:Ignore">b.<span style="font:7.0pt "Times New Roman"">
</span></span><![endif]>This addresses only #1 above.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Is there any way I can leverage existing scheduler mechanisms to solve this VM placement problem? If not, do you have thoughts/comments on what changes are needed?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks, and apologies in advance if I am not clear. Please feel free to ask questions.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Cheers,<o:p></o:p></p>
<p class="MsoNormal">Sundar<span style="color:#1F497D"><o:p></o:p></span></p>
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