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<p style="margin-top:0; margin-bottom:0">Hi Alex,</p>
<p style="margin-top:0; margin-bottom:0"> </p>
<p style="margin-top:0; margin-bottom:0">I thought the value in Nova was established right from the time the initial blueprint was established. Group of VMs with policies as described in the document.</p>
<p style="margin-top:0; margin-bottom:0">Once we have described and registered the group using these apis, it adds value to be schedule them as a whole.</p>
<p style="margin-top:0; margin-bottom:0"> </p>
<p style="margin-top:0; margin-bottom:0">With the bigger roadmap in mind we have to start somewhere.</p>
<p style="margin-top:0; margin-bottom:0"> </p>
<p style="margin-top:0; margin-bottom:0">Thanks,</p>
<p style="margin-top:0; margin-bottom:0">Yathi.</p>
<p style="margin-top:0; margin-bottom:0"> </p>
<p style="margin-top:0; margin-bottom:0"> </p>
<p style="margin-top:0; margin-bottom:0"> </p>
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<p style="margin-top:0; margin-bottom:0">Sent from my LG G2, an AT&T 4G LTE smartphone</p>
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<p id="last_enter" style="margin-top:0; margin-bottom:0"> </p>
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<p style="margin-top:0; margin-bottom:0">------ Original message------</p>
<p style="margin-top:0; margin-bottom:0"><b>From: </b>Alex Glikson</p>
<p style="margin-top:0; margin-bottom:0"><b>Date: </b>Tue, 10/29/2013 3:11 PM</p>
<p style="margin-top:0; margin-bottom:0"><b>To: </b>OpenStack Development Mailing List (not for usage questions);</p>
<p style="margin-top:0; margin-bottom:0"><b>Subject:</b>Re: [openstack-dev] [nova][scheduler] Instance Group Model and APIs - Updated document with an example request payload</p>
<p style="margin-top:0; margin-bottom:0"> </p>
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<div><font size="2" face="sans-serif">If we envision the main benefits only after (parts of) this logic moves outside of Nova (and starts addressing other resources) -- would it be still worth maintaining an order of 5K LOC in Nova to support this feature?
Why not going for the 'ultimate' solution in the first place then, keeping in Nova only the mandatory enablement (TBD)?</font>
<br>
<font size="2" face="sans-serif">Alternatively, if we think that there is value in having this just in Nova -- would be good to understand the exact scenarios which do not require awareness of other resources (and see if they are important enough to maintain
those 5K LOC), and how exactly this can gradually evolve into the 'ultimate' solution.</font>
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<font size="2" face="sans-serif">Or am I missing something?</font> <br>
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<font size="2" face="sans-serif">Alex</font> <br>
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<br>
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<font size="1" color="#5f5f5f" face="sans-serif">From: </font><font size="1" face="sans-serif">"Yathiraj Udupi (yudupi)" <yudupi@cisco.com></font>
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<font size="1" color="#5f5f5f" face="sans-serif">To: </font><font size="1" face="sans-serif">"OpenStack Development Mailing List (not for usage questions)" <openstack-dev@lists.openstack.org>,
</font><br>
<font size="1" color="#5f5f5f" face="sans-serif">Date: </font><font size="1" face="sans-serif">29/10/2013 11:46 PM</font>
<br>
<font size="1" color="#5f5f5f" face="sans-serif">Subject: </font><font size="1" face="sans-serif">Re: [openstack-dev] [nova][scheduler] Instance Group Model and APIs - Updated document with an example request payload</font>
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<font size="2" face="Calibri">Thanks Alex, Mike, Andrew, Russel for your comments. This ongoing API discussion started in our scheduler meetings, as a first step to tackle in the Smarter resource placement ideas - See the doc for reference -
</font><a href="https://docs.google.com/document/d/1IiPI0sfaWb1bdYiMWzAAx0HYR6UqzOan_Utgml5W1HI/edit"><font size="2" color="blue" face="Calibri"><u>https://docs.google.com/document/d/1IiPI0sfaWb1bdYiMWzAAx0HYR6UqzOan_Utgml5W1HI/edit</u></font></a><font size="2" face="Calibri">
This roadmap calls for a unified resource placement decisions to be taken covering resources across services, starting from a complete topology request with all the necessary nodes/instances/resources, their connections, and the policies.
</font><br>
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<font size="2" face="Calibri">However we agreed that we will first address the defining of the required APIs, and start the effort to make this happen within Nova, using VM instances groups, with policies. </font>
<br>
<font size="2" face="Calibri">Hence this proposal for the instance groups. </font>
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<br>
<font size="2" face="Calibri">The entire group needs to be placed as a whole, at least the first step is to find an ideal placement choices for the entire group. Once the placement has been identified (using a smart resource placement engine that addresses
solving the entire group), we then focus on ways to schedule them as a whole. This is not part of the API discussion, however important for the smart resource placement ideas. This definitely involves concepts such as reservation, etc. Heat or Heat APIs
could be a choice to enable the final orchestration, but I am not commenting on that here.</font>
<br>
<br>
<font size="2" face="Calibri">The APIs effort here is an attempt to provide clean interfaces now to be able to represent this instance group, and save them, and also define apis to create them. The actual implementation will have to rely on one or more services
to - 1. to make the resource placement decisions, 2. then actually provision them, orchestrate them in the right order, etc.
</font><br>
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<font size="2" face="Calibri">The placement decisions itself can happen in a module that can be a separate service, and can be reused by different services, and it also needs to have a global vision of all the resources. (Again all of this part of the scope
of smart resource placement topic). </font><br>
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<font size="2" face="Calibri">Thanks,</font> <br>
<font size="2" face="Calibri">Yathi. </font><br>
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<font size="2" face="Calibri">On 10/29/13, 2:14 PM, "Andrew Laski" <</font><a href="mailto:andrew.laski@rackspace.com"><font size="2" color="blue" face="Calibri"><u>andrew.laski@rackspace.com</u></font></a><font size="2" face="Calibri">> wrote:</font>
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<font size="2" face="Calibri">On 10/29/13 at 04:05pm, Mike Spreitzer wrote:</font>
<br>
<font size="2" face="Calibri">Alex Glikson <</font><a href="mailto:GLIKSON@il.ibm.com"><font size="2" color="blue" face="Calibri"><u>GLIKSON@il.ibm.com</u></font></a><font size="2" face="Calibri">> wrote on 10/29/2013 03:37:41 AM:</font>
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<font size="2" face="Calibri">1. I assume that the motivation for rack-level anti-affinity is to</font>
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<font size="2" face="Calibri">survive a rack failure. Is this indeed the case?</font>
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<font size="2" face="Calibri">This is a very interesting and important scenario, but I am curious</font>
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<font size="2" face="Calibri">about your assumptions regarding all the other OpenStack resources</font>
<br>
<font size="2" face="Calibri">and services in this respect.</font> <br>
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<font size="2" face="Calibri">Remember we are just starting on the roadmap. Nova in Icehouse, holistic</font>
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<font size="2" face="Calibri">later</font> <br>
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<font size="2" face="Calibri">2. What exactly do you mean by "network reachibility" between the</font>
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<font size="2" face="Calibri">two groups? Remember that we are in Nova (at least for now), so we</font>
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<font size="2" face="Calibri">don't have much visibility to the topology of the physical or</font>
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<font size="2" face="Calibri">virtual networks. Do you have some concrete thoughts on how such</font>
<br>
<font size="2" face="Calibri">policy can be enforced, in presence of potentially complex</font>
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<font size="2" face="Calibri">environment managed by Neutron?</font> <br>
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<font size="2" face="Calibri">I am aiming for the holistic future, and Yathi copied that from an example</font>
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<font size="2" face="Calibri">I drew with the holistic future in mind. While we are only addressing</font>
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<font size="2" face="Calibri">Nova, I think a network reachability policy is inapproprite.</font>
<br>
<br>
<font size="2" face="Calibri">3. The JSON somewhat reminds me the interface of Heat, and I would</font>
<br>
<font size="2" face="Calibri">assume that certain capabilities that would be required to implement</font>
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<font size="2" face="Calibri">it would be similar too. What is the proposed approach to</font>
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<font size="2" face="Calibri">'harmonize' between the two, in environments that include Heat? What</font>
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<font size="2" face="Calibri">would be end-to-end flow? For example, who would do the</font>
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<font size="2" face="Calibri">orchestration of individual provisioning steps? Would "create"</font>
<br>
<font size="2" face="Calibri">operation delegate back to Heat for that? Also, how other</font>
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<font size="2" face="Calibri">relationships managed by Heat (e.g., links to storage and network)</font>
<br>
<font size="2" face="Calibri">would be incorporated in such an end-to-end scenario?</font>
<br>
<br>
<font size="2" face="Calibri">You raised a few interesting issues.</font> <br>
<br>
<font size="2" face="Calibri">1. Heat already has a way to specify resources, I do not see why we should</font>
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<font size="2" face="Calibri">invent another.</font> <br>
<br>
<font size="2" face="Calibri">2. Should Nova call Heat to do the orchestration? I would like to see an</font>
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<font size="2" face="Calibri">example where ordering is an issue. IMHO, since OpenStack already has a</font>
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<font size="2" face="Calibri">solution for creating resources in the right order, I do not see why we</font>
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<font size="2" face="Calibri">should invent another.</font> <br>
<br>
<font size="2" face="Calibri">Having Nova call into Heat is backwards IMO. If there are specific
</font><br>
<font size="2" face="Calibri">pieces of information that Nova can expose, or API capabilities to help
</font><br>
<font size="2" face="Calibri">with orchestration/placement that Heat or some other service would like
</font><br>
<font size="2" face="Calibri">to use then let's look at that. Nova has placement concerns that extend
</font><br>
<font size="2" face="Calibri">to finding a capable hypervisor for the VM that someone would like to
</font><br>
<font size="2" face="Calibri">boot, and then just slightly beyond. If there are higher level
</font><br>
<font size="2" face="Calibri">decisions to be made about placement decisions I think that belongs
</font><br>
<font size="2" face="Calibri">outside of Nova, and then just tell Nova where to put it.</font>
<br>
<br>
<br>
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<font size="2" face="Calibri">Thanks,</font> <br>
<font size="2" face="Calibri">Mike</font> <br>
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