[qeeens][neutron] migrating from iptables_hybrid to openvswitch

Jakub Libosvar jlibosva at redhat.com
Thu Mar 12 19:50:31 UTC 2020

On 12/03/2020 11:38, Ignazio Cassano wrote:
> Hello All, I am facing some problems migrating from iptables_hybrid
> frirewall to openvswitch firewall on centos 7 queens,
> I am doing this because I want enable security groups logs which require
> openvswitch firewall.
> I would like to migrate without restarting my instances.
> I startded moving all instances from compute node 1.
> Then I configured openvswitch firewall on compute node 1,
> Instances migrated from compute node 2 to compute node 1 without problems.
> Once the compute node 2 was empty, I migrated it to openvswitch.
> But now instances does not migrate from node 1 to node 2 because it
> requires the presence of qbr bridge on node 2
> This happened because migrating instances from node2 with iptables_hybrid
> to compute node 1 with openvswitch, does not put the tap under br-int as
> requested by  openvswich firewall, but qbr is still present on compute node
> 1.
> Once I enabled openvswitch on compute node 2, migration from compute node 1
> fails because it exprects qbr on compute node 2 .
> So I think I should moving on the fly tap interfaces from qbr to br-int on
> compute node 1 before migrating to compute node 2 but it is a huge work on
> a lot of instances.
> Any workaround, please ?
> Ignazio

I may be a little outdated here but to the best of my knowledge there
are two ways how to migrate from iptables to openvswitch.

1) If you don't mind the intermediate linux bridge and you care about
logs, you can just change the config file on compute node to start using
openvswitch firewall and restart the ovs agent. That should trigger a
mechanism that deletes iptables rules and starts using openflow rules.
It will leave the intermediate bridge there but except the extra hop in
networking stack, it doesn't mind.

2) With multiple-port binding feature, what you described above should
be working. I know Miguel spent some time working on that so perhaps he
has more information about which release it should be functional at, I
think it was Queens. Not sure if any Nova work was required to make it work.

Hope that helps.

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