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<p><font size="2" face="sans-serif">It is perhaps worth mentioning that there is an effort to implement a generic synchronization mechanism (between Neutron and backend controllers/devices) in the ML2 plugin [1]. A possible framework for its eventual implementation is in an early discussion/proof-of-concept WIP state [2].</font><br>
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<font size="2" face="sans-serif">-Mohammad</font><br>
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<font size="2" face="sans-serif">[1] </font><a href="https://blueprints.launchpad.net/neutron/+spec/ml2-driver-sync"><font size="2" face="sans-serif">https://blueprints.launchpad.net/neutron/+spec/ml2-driver-sync</font></a><br>
<font size="2" face="sans-serif">[2] </font><a href="https://review.openstack.org/#/c/154333/"><font size="2" face="sans-serif">https://review.openstack.org/#/c/154333/</font></a><br>
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<img width="16" height="16" src="cid:1__=0ABBF499DFC208058f9e8a93df938@us.ibm.com" border="0" alt="Inactive hide details for Cory Benfield ---03/16/2015 04:48:27 AM---On Sun, Mar 15, 2015 at 22:37:59, Sławek Kapłoński wrote"><font size="2" color="#424282" face="sans-serif">Cory Benfield ---03/16/2015 04:48:27 AM---On Sun, Mar 15, 2015 at 22:37:59, Sławek Kapłoński wrote: > Maybe good idea for the beginning could</font><br>
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<font size="1" color="#5F5F5F" face="sans-serif">From: </font><font size="1" face="sans-serif">Cory Benfield <Cory.Benfield@metaswitch.com></font><br>
<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">03/16/2015 04:48 AM</font><br>
<font size="1" color="#5F5F5F" face="sans-serif">Subject: </font><font size="1" face="sans-serif">Re: [openstack-dev] [neutron] Generic question about synchronizing neutron agent on compute node with DB</font><br>
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<tt><font size="2">On Sun, Mar 15, 2015 at 22:37:59, Sławek Kapłoński wrote:<br>
> Maybe good idea for the beginning could be to implement some periodic<br>
> task<br>
> called from agent to check db config and compare it with real state on<br>
> host?<br>
> What do You think? Or maybe I'm competly wrong with such idea and it<br>
> should be<br>
> done in different way?<br>
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This is almost exactly what we do in our Calico ML2 driver. Each of our agents will periodically request its complete state from a neutron-server node and will ensure that its local state matches that expected state. This interval is configurable, to allow administrators to make a trade-off between DB/network load and convergence time.<br>
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With reliable transport this is in principle almost never needed (messages only really get lost on agent crash, and the agent will resynchronize when it starts back up anyway), but it provides assurances that the fabric is capable of bringing itself into consistency without administrator intervention.<br>
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Having similar function in other neutron agents would be valuable for the exact same reasons, but do bear in mind the potentially increased load this kind of resynchronization can place on databases and servers.<br>
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Cory<br>
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