The current suggested way for DHCP agent fault tolerance is multiple agents per network. Is there a reason you don't want to use that option? On Oct 20, 2014 5:13 PM, "Noel Burton-Krahn" <n...@pistoncloud.com> wrote:
> Thanks, Robert. > > So, ML2 needs the host attribute to match to bind the port. My other > requirement is that the dhcp agent must be able to migrate to a new host on > failover. The issue there is that if the dhcp service starts on a new host > with a new host name, then it will not take over the networks that were > served by the old host name. I'm looking for a way to start the dhcp agent > on a new host using the old host's config. > > -- > Noel > > > On Mon, Oct 20, 2014 at 11:10 AM, Robert Kukura <kuk...@noironetworks.com> > wrote: > >> Hi Noel, >> >> The ML2 plugin uses the binding:host_id attribute of port to control port >> binding. For compute ports, nova sets binding:host_id when >> creating/updating the neutron port, and ML2's openvswitch mechanism driver >> will look in agents_db to make sure the openvswitch L2 agent is running on >> that host, and that it has a bridge mapping for any needed physical network >> or has the appropriate tunnel type enabled. The binding:host_id attribute >> also gets set on DHCP, L3, and other agents' ports, and must match the host >> of the openvswitch-agent on that node or ML2 will not be able to bind the >> port. I suspect your configuration may be resulting in these not matching, >> and the DHCP port's binding:vif_type attribute being 'binding_failed'. >> >> I'd suggest running "neutron port-show" as admin on the DHCP port to see >> what the values of binding_vif_type and binding:host_id are, and running >> "neutron agent-list" as admin to make sure there is an L2 agent on that >> node and maybe "neutron agent-show" as admin to get that agents config >> details. >> >> -Bob >> >> >> >> On 10/20/14 1:28 PM, Noel Burton-Krahn wrote: >> >> I'm running OpenStack Icehouse with Neutron ML2/OVS. I've configured the >> ml2-ovs-plugin on all nodes with host = the IP of the host itself. >> However, my dhcp-agent may float from host to host for failover, so I >> configured it with host="floating". That doesn't work. In this case, the >> ml2-ovs-plugin creates a namespace and a tap interface for the dhcp agent, >> but OVS doesn't route any traffic to the dhcp agent. It *does* work if the >> dhcp agent's host is the same as the ovs plugin's host, but if my dhcp >> agent migrates to another host, it loses its configuration since it now has >> a different host name. >> >> So my question is, what does host mean for the ML2 dhcp agent and host >> can I get it to work if the dhcp agent's host != host for the ovs plugin? >> >> Case 1: fails: running with dhcp agent's host = "floating", ovs >> plugin's host = IP-of-server >> dhcp agent is running in netns created by ovs-plugin >> dhcp agent never receives network traffic >> >> Case 2: ok: running with dhcp agent's host = ovs plugin's host = >> IP-of-server >> dhcp agent is running in netns created by ovs-plugin (different tap >> name than case 1) >> dhcp agent works >> >> -- >> Noel >> >> >> >> >> >> >> _______________________________________________ >> OpenStack-dev mailing >> listOpenStack-dev@lists.openstack.orghttp://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> >> >> >> _______________________________________________ >> OpenStack-dev mailing list >> OpenStack-dev@lists.openstack.org >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >> >> > > _______________________________________________ > OpenStack-dev mailing list > OpenStack-dev@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > >
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