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<div class="moz-cite-prefix">On 1/29/19 1:25 AM, Duarte Cardoso,
Igor wrote:<br>
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<p class="MsoNormal">Hi Neutron,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I've been internally collaborating on the
``dvr_bridge`` L3 agent mode [1][2][3] work (David
Shaughnessy, Xubo Zhang), which allows the L3 agent to make
use of Open vSwitch / OpenFlow to implement ``distributed``
IPv4 Routers thus bypassing kernel namespaces and iptables and
opening the door for higher performance by keeping packets in
OVS for longer.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I want to share a few questions in order to
gather feedback from you. I understand parts of these
questions may have been answered in the past before my
involvement, but I believe it's still important to revisit and
clarify them. This can impact how long it's going to take to
complete the work and whether it can make it to stein-3.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">1. Should OVS support also be added to the
legacy router?<o:p></o:p></p>
<p class="MsoNormal">And if so, would it make more sense to have
a new variable (not ``agent_mode``) to specify what backend to
use (OVS or kernel) instead of creating more combinations?</p>
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Personally, I would like to see all routers implemented completely
in the OVS data path. We can't do everything at once, so the
DVR-first approach here seems reasonable to me. As to the question
of config flags, agent_mode has a specific meaning. It effectively
tells the agent what role it's playing (SNAT, SNAT_HA, etc.), not
how to do it. dvr_bridge isn't a new mode, it's really a change to
the backend implementation of the router (ie the "how"). Because of
that, I'm partial to an "agent_mode" flag which will toggle the
router implementation between OVS and namespace implementations.<br>
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cite="mid:E09EC9A2DDB2914E953966C44BEF9CF633F86A76@ORSMSX103.amr.corp.intel.com">
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<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">2. What is expected in terms of CI for
this? Regarding testing, what should this first patch include
apart from the unit tests? (since the l3_agent.ini needs to be
configured differently).<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">3. What problems can be anticipated by
having the same agent managing both kernel and OVS powered
routers (depending on whether they were created as
``distributed``)?<o:p></o:p></p>
<p class="MsoNormal">We are experimenting with different ways of
decoupling RouterInfo (mainly as part of the L3 agent refactor
patch) and haven't been able to find the right balance yet. On
one end we have an agent that is still coupled with
kernel-based RouterInfo, and on the other end we have an agent
that either only accepts OVS-based RouterInfos or only
kernel-based RouterInfos depending on the ``agent_mode``.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">We'd also appreciate reviews on the 2
patches [4][5]. The L3 refactor one should be able to pass
Zuul after a recheck.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">[1] Spec:
<a class="moz-txt-link-freetext" href="https://blueprints.launchpad.net/neutron/+spec/openflow-based-dvr">https://blueprints.launchpad.net/neutron/+spec/openflow-based-dvr</a><o:p></o:p></p>
<p class="MsoNormal">[2] RFE:
<a class="moz-txt-link-freetext" href="https://bugs.launchpad.net/neutron/+bug/1705536">https://bugs.launchpad.net/neutron/+bug/1705536</a><o:p></o:p></p>
<p class="MsoNormal">[3] Gerrit topic:
<a class="moz-txt-link-freetext" href="https://review.openstack.org/#/q/topic:dvr_bridge+(status:open+OR+status:merged)">https://review.openstack.org/#/q/topic:dvr_bridge+(status:open+OR+status:merged)</a><o:p></o:p></p>
<p class="MsoNormal">[4] L3 agent refactor patch:
<a class="moz-txt-link-freetext" href="https://review.openstack.org/#/c/528336/29">https://review.openstack.org/#/c/528336/29</a><o:p></o:p></p>
<p class="MsoNormal">[5] dvr_bridge patch:
<a class="moz-txt-link-freetext" href="https://review.openstack.org/#/c/472289/17">https://review.openstack.org/#/c/472289/17</a><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thank you!<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-IE">Best regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-IE">Igor D.C.<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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</blockquote>
-Ryan<br>
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