Hi there. I was wondering if someone could help me with the following issue. I have a server with two NICs. I used to have eth0 as the internet facing device and I would attach eth1 to br1 and run a nat-ed private network for the VMs which would use br1 as the gateway.
I have recently changed my configuration. For the purposes of redundancy I have now aggregated eth0 and eth1 into a bonded device, bond0. I want to keep the VMs on a private network and haven't quite worked out the right way to do this. If I attach bond0 to a bridge, it seems I have to assign public IPs to the VMs (please correct me if I'm wrong). I have tried a few other configurations:
- create dummy0 and attach that to xenbr0 which is intended to be the private network gateway
- create an alias bond0:1 and attach that to xenbr0
- I've also tried various combinations with the xen routing and nat scripts (which I'd rather not use if possible given they are becoming deprecated)
- for all of the above I've used IP tables for the forwarding and masquerading between the 'attempted' private network and the external facing NIC
In all cases, I either end up cutting off access to bond0 or the private network.
Is what I'm trying to do - have a single external interface and a single virtual internal nat-ed interface which can reach the outside internet – possible? If so, could someone tell me what the basic setup looks like. I am using ubuntu12.04 for Dom0 so it would be helpful to get some guidance on how the 'interfaces' file should be constructed but most important is to know whether this can be done in theory (or do I not have enough interfaces?). I have read the wiki quite extensively and I appreciate there are some sections covering this subject but nothing I've tried in practice has worked so far.
For what's it worth, here's the latest version of my interfaces file where I'm trying out the dummy device. Thanks in advance for any assistance.
auto lo
iface lo inet loopback
# The bonded network interface
auto bond0
iface bond0 inet static
address [*** ]
netmask 255.255.255.240
gateway [ ***]
bond-slaves none
bond-mode active-backup
bond-miimon 100
# Enslave all the physical interfaces
auto eth0
iface eth0 inet manual
bond-master bond0
auto eth1
iface eth1 inet manual
bond-master bond0
# dummy interface
auto dummy0
iface dummy0 inet manual
# Configure the bridging interface
auto xenbr0
iface xenbr0 inet static
address 10.1.1.65
netmask 255.255.255.192
gateway 10.1.1.65
bridge-ports dummy0
bridge-fd 9
bridge-hello 2
bridge-maxage 12
bridge-stp off
