[openstack-dev] [devstack] A few questions on configuring DevStack for Neutron

Christopher Aedo doc at aedo.net
Tue Oct 6 18:09:53 UTC 2015

On Sun, Oct 4, 2015 at 9:16 PM, Mike Spreitzer <mspreitz at us.ibm.com> wrote:
> [Apologies for re-posting, but I botched the subject line the first time and
> know that people use filters.]
> I have been looking at
> http://docs.openstack.org/developer/devstack/guides/neutron.htmland wonder
> about a few things.
> In the section
> http://docs.openstack.org/developer/devstack/guides/neutron.html#using-neutron-with-a-single-interfacethere
> is a helpful display of localrc contents.  It says, among other things,
>        OVS_PHYSICAL_BRIDGE=br-ex
>        PUBLIC_BRIDGE=br-ex
> In the next top-level section,
> http://docs.openstack.org/developer/devstack/guides/neutron.html#using-neutron-with-multiple-interfaces,
> there is no display of revised localrc contents and no mention of changing
> either bridge setting.  That is an oversight, right?  I am guessing I need
> to set OVS_PHYSICAL_BRIDGEand PUBLIC_BRIDGEto different values, and the
> exhibited `ovs-vsctl` commands in this section apply to
> $OVS_PHYSICAL_BRIDGE.  Is that right?  Are there other revisions I need to
> make to localrc?
> Looking at
> http://docs.openstack.org/networking-guide/scenario_legacy_ovs.html(or, in
> former days, the doc now preserved at
> http://docs.ocselected.org/openstack-manuals/kilo/networking-guide/content/under_the_hood_openvswitch.html)
> I see the name br-ex used for $PUBLIC_BRIDGE--- not $OVS_PHYSICAL_BRIDGE,
> right?  Wouldn't it be less confusing if
> http://docs.openstack.org/developer/devstack/guides/neutron.htmlused a name
> other than "br-ex" for the exhibited commands that apply to
> The section
> http://docs.openstack.org/developer/devstack/guides/neutron.html#neutron-networking-with-open-vswitchbuilds
> on
> http://docs.openstack.org/developer/devstack/guides/neutron.html#using-neutron-with-multiple-interfacesNOT
> http://docs.openstack.org/developer/devstack/guides/neutron.html#using-neutron-with-a-single-interface---
> right?  Could I stop after reading that section, or must I go on to
> http://docs.openstack.org/developer/devstack/guides/neutron.html#neutron-networking-with-open-vswitch-and-provider-networks?
> The exhibited localrc contents in section
> http://docs.openstack.org/developer/devstack/guides/neutron.html#using-neutron-with-a-single-interfaceinclude
> both of these:
>        Q_L3_ENABLED=True
> and nothing gainsays either of them until section
> http://docs.openstack.org/developer/devstack/guides/neutron.html#neutron-networking-with-open-vswitch-and-provider-networks---
> where we first see
>        Q_L3_ENABLED=False
> Is it true that all the other sections want both Q_L3_ENABLED and

I'd love to see a response from someone who can make sense of this
too.  With my evangelist hat on, I usually tell people who want to get
started with OpenStack development to start with Devstack.  More often
than not, they have trouble with the networking side.  As discussed
and hoped for in the "just get me a network" spec, there's definitely
a need for a less painful path for users.  Likewise we should be able
to share a devstack config that just works, but at the same time shows
off some of the great capabilities of neutron (and all the other good
bits of OpenStack).

Can anyone weigh in here on this issue?


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