Devstack single NIC configuration

I made a post recently on setting up Openstack for development using Devstack but failed to mention some other tips on how to build a lab out of anything. I'm a big fan of the Gigabyte Brix PC kit systems, with the caveat being that they only have a single NIC. You could connect a wireless USB adapter but there is a much easier way to have multiple networks....

Old fashioned bridging....the joy

Yes....bridging and VLANS still work...and fairly well within a Linux system. First install the dependencies:

sudo apt-get install bridge-utils

Configure a bridge interface in /etc/network/interfaces with some extra parameters:

# Bridge interface 
auto br0 
iface br0 inet 
static address # Reserve this IP from your DHCP server 
gateway # Use your local network gateway 
bridge_ports eth0 
bridge_fd 0 
bridge_hello 2 
bridge_maxage 12 
bridge_stp off

Restart networking:
sudo service networking restart

Create a VLAN network interface on eth0 using VLAN ID 0 ( is used as an IP example):

modprobe 8021q 
vconfig add eth0 5 
ifconfig eth0.0:5 netmask up

Ensure you have ip forwarding, proxy ARP and a NAT rule enabled:

echo 1 > /proc/sys/net/ipv4/ip_forward 
echo 1 > /proc/sys/net/ipv4/conf/eth0/proxy_arp 
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

Let's make it permanent in /etc/network/interfaces:

auto eth0.5 
iface eth0.5 inet static 
address netmask 
vlan-raw-device eth0

Now modify your Devstack local.conf file to include your new VLAN interface and range:


Follow the rest of the instructions and you'll be stacking in no time. Until next time....cheers.