Floating ips on separate interface + external gateway does not work

[Vish Ishaya]

When using flatdhcp with an external gateway, floating ips do not work properly if they are on a separate interface. This is because incoming traffic will come along the floating interface but outgoing traffic still goes out the default gateway out the flat network interface. This leads to an asymetric route.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/19141

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/19141
Committed: http://github.com/openstack/nova/commit/6ee9880cade60d474ad098b80d78cdbf8032a327
Submitter: Jenkins
Branch: master

commit 6ee9880cade60d474ad098b80d78cdbf8032a327
Author: Vishvananda Ishaya <email address hidden>
Date: Fri Jan 4 18:31:41 2013 -0800

    Fix floating ips with external gateway

    If dnsmasq is configured to use an external gateway, then floating
    ips on other interfaces do not work properly. This is because
    outgoing traffic is no longer snatted to the floating ip.

    This patch fixes it by adding an ebtables rule to force traffic
    from ips that have a floating ip associated to route instead
    of bridge.

    Fixes bug 1096985

    Change-Id: I8e4904660d42fe51c44b66686bed9f5d622693bd