[Rdo-list] Openstack Liberty with DVR and VLAN overlay

Hi, I have a simple single nic bare metal set up much like this - https://answers.launchpad.net/neutron/+question/228376 Tenant networks are VLANs, and the external network a VLAN provider network. This enables me to have one bridge which allows the VLAN overlays to pass between nodes/physical switches, and importantly allows external access via floating ip through the external provider network VLAN. This was all working fine, but I wanted to install DVR. I saw that DVR functionality had relatively recently been added for VLAN overlays (Kilo and beyond) https://blueprints.launchpad.net/neutron/+spec/neutron-ovs-dvr-vlan So I enabled DVR, noting that for VLAN overlays l2population is not required. I created two instances, two tenant networks one with a normal router (non DVR) and one with a DVR router. I first tested SNAT on both. Worked fine (I could ping externally from the instances) I then applied a FIP to the non DVR routed instance. I could ping the instance from the external network, so all working fine. I then applied a FIP to the DVR routed instance. This is where the problems began. I could not ping externally from the instance, and I could not ping the instance from the external network. I looked at the traffic flow schematic outlined here for North/South FIP (allowing for the fact I am not using tunneling) - http://docs.openstack.org/liberty/networking-guide/scenario_dvr_ovs.html I noticed that the fg interface from the FIP namespace in my compute node was NOT attached to br-int as in the guide, but was attached to my VLAN bridge. This seemed odd. I thought that maybe this would have an effect on the tagging, so tried manually adding the tag for the external provider network VLAN to the fg port on the VLAN bridge ovs-vsctl set port fg-15df2853-c2 tag=1041 Suddenly it all started working. I could now ping externally from the DVR routed instance, and I could ping the instance from the external network. Please can someone explain why I am seeing this behavior? Thanks Charles -- Charles Short Cloud Engineer Virtualization and Cloud Team European Bioinformatics Institute (EMBL-EBI) Tel: +44 (0)1223 494205