[Openstack-operators] Howto setup quantum for floating IPs similar to the way nova-network did it?

Nick Bartos nick at pistoncloud.com
Tue Jan 29 22:29:52 UTC 2013

I'm trying to get quantum floating IPs working in this configuration.
Nova-network was working fine before, but now we are switching to
quantum for better configurability in some installations. Here is a
brief description of the setup:

The only router for all openstack networks is a (real) 10G ethernet
switch. There is one untagged network used for internal communication
(not exposed to the VMs). There are 2 additional networks (tagged
VLANs on the same physical network), one for VM fixed addresses, and
one for public floating addresses. All hosts have access to all
networks, and no hosts have dedicated tasks (there are no
networking-only, compute-only, etc hosts, but services that there can
be only one/few of are master elected). Currently quantum is using the
linux bridge plugin, but that will likely change to something else

The NAT for the floating IPs needs to be done on the host where the VM
resides. Having a separate networking-only NAT host will not work in
our configuration. This is because we do not want to bottleneck
network I/O through any one host, and also so that if one host fails
it will not affect the network on other surviving hosts. From what I
can tell by the docs, a quantum router for NAT may need to be created
for each host to make this happen, although I'm not really sure.

Currently quantum-server is a master elected service on a floating IP
(which is managed outside of openstack), so it runs on only one node
at a time. The dhcp, linuxbridge, and l3 agents are running on each

How exactly should quantum be set up to do this? Or is this
configuration not feasible using quantum?

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