Re: [libvirt] how do I stop libvirt futzing with my network configuration?
On Sat, Nov 28, 2009 at 10:41:58PM +0000, Nix wrote:
On 28 Nov 2009, Ian Woodstock verbalised:
> I suspect that's why libvirt won't let you connect to it, since
> libvirt is looking for a "shared physical device" and there's not a
> device in the bridge.
Gah. So libvirt won't let me connect a bunch of devices to a bridge
without that bridge being bridged to something already? So you
can't have a pile of bridges with VMs on them *routed* to the rest of
the net?
Please distinguish between libvirt & virt-manager. libvirt allows this
find - it is happy to connect VMs to any bridge device. virt-manager is
providing a higher level UI which only presents a smaller subset of the
functionality. In this case is only supporting the libvirt managed NAT
mode, and bridging of a physical inteface.
An alternative to using virt-manager is to install your VMs using the
command line 'virt-install' tool which offers a much greater level of
functionality - in this case you'd be able to simply add
--network bridge:linux-net
to the args when installing a VM to make it use your bridge. The
virt-install manpage has lots of examples of all the other args.
>> There's no iptables at all on this particular box (at
least not yet,
>> although it may turn up later on when I put Windows guests on here: I'm
>> not having *them* running around free).
>>
>
> So it sounds like the root of your issue now is that you're using
> dummy network device.
> Is that being done temporarily now because you don't have a network
> plumbed in or is there some other use case?
It was an emergency hack when I found virt-manager not noticing bridges
that had nothing on them (it said 'not bridged'). I stuck the dummy
device on it and it started working. However, this appears to have
been transient.
... In the code, the only place where it checks if a bridge exists
is in src/network/bridge_driver.c:networkFindActiveConfigs(), and
it only bothers to check *that* if there's a config file in the
NETWORK_STATE_DIR (/var/lib/libvirt/network):
Again the network driver here is libvirt's NAT based networking, not
regular physical device bridging. Yes, its a bad naming convention :-)
The physical interface management APIs are provided by the 'interface'
driver (ie the virsh iface-XXX commands).
Daniel
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