Open Stack

Hi,

I have proposed a recent patch, that when using Neutron as the
networking component in DevStack, the PUBLIC_INTERFACE that has been set
should automatically be added to the OVS_PHYSICAL_BRIDGE.

https://review.openstack.org/#/c/158424/

There are a couple motivations for this patch. The first is that in my
Vagrant project, I've been using chef[0] to attach the public interface
to the OVS bridge, so that when a floating IP is NAT'd traffic flows
from the interface attached to the router where the floating IP range is
advertised, into the L3 agent.

This is basically the same step documented for setting up a production
Neutron install[1]. The fact that we are not doing this for DevStack
installations is an oversight that should be corrected.

The second motivation for this patch is to help transition DevStack
users from Nova-Networking. Recently, we tried to move Neutron to being
the default, but the lack of code to configure DevStack on machines with
a single network interface caused a lot of issues and had to be
reverted.

In cases where DevStack is being run on a developer machine, where only
one physical interface is present, DevStack will remove the IP address
that has been assigned to the machine and adds it to the
OVS_PHSYICAL_BRIDGE, so that the machine as well as the OpenStack APIs
are reachable, while also allowing the usage of floating IPs.

An example local.conf shows how this is configured. On this machine, we
have a router that advertises the 192.168.27.0/24 prefix. The DevStack
machine will be assigned 192.168.27.2 from DHCP, and the remaining IPs
in the /24 will be used for floating IP addresses.

	HOST_IP=192.168.27.2
	FLAT_INTERFACE=eth0
	PUBLIC_INTERFACE=eth0
	FIXED_RANGE=10.0.0.0/24
	FLOATING_RANGE=192.168.27.0/24
	PUBLIC_NETWORK_GATEWAY=192.168.27.1

	disable_service n-net
	enable_service q-svc
	enable_service q-agt
	enable_service q-dhcp
	enable_service q-meta
	enable_service q-l3

	Q_USE_SECGROUP=True
	ENABLE_TENANT_VLANS=True
	TENANT_VLAN_RANGE=3001:4000
	OVS_PHYSICAL_BRIDGE=br-ex
	Q_L3_ENABLED=True
	Q_FLOATING_ALLOCATION_POOL=start=192.168.27.3,end=192.168.27.254

I'd be interested in feedback from everyone about my thought process,
code, and if I'm on the right track.

[0]: https://github.com/sc68cal/chef-devstack/blob/master/recipes/default.rb#L50
[1]: http://docs.openstack.org/admin-guide-cloud/content/install_neutron-l3.html
[2]: https://review.openstack.org/#/c/153208/

-- 
Sean M. Collins