[openstack-dev] [Neutron] Why doesn't ml2-ovs work when it's "host" != the dhcp agent's host?

Noel Burton-Krahn noel at pistoncloud.com
Mon Oct 20 17:28:33 UTC 2014


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
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20141020/01056339/attachment.html>


More information about the OpenStack-dev mailing list