[virt-tools-list] Creating bridge to WiFi fails with no link present

[Cole Robinson]

On 01/16/2014 06:51 PM, Paul Nickerson wrote:
> Hello, I am attempting to create a bridge to WiFi on Fedora 19, but it is failing.
> 
> In Virtual Machine Manager's View > Connection Details > Network Interfaces >
> Add Interface, I was able to create a bridge to my Lenovo ThinkPad T510
> laptop's ethernet port, and it works with my VM. However, when I try the same
> procedure to create a bridge to my WiFi card, it fails.
> 
> These are the options I am setting:
> ===
> Interface type: Bridge
> Start mode: onboot
> Activate now: checked
> Interface to bridge: wlp3s0 (em1, virbr0-nic, and lo are also available
> options; em1 is my ethernet port)
> ===
> 
> This is the error I get:
> ===
> Error creating interface: 'Could not create interface: internal error failed
> to create (start) interface br1: failed to execute external program - Running
> 'ifup br1' failed with exit code 1: 
> Determining IP information for br1... failed; no link present.  Check cable?
> '
> 
> Traceback (most recent call last):
>   File "/usr/share/virt-manager/virtManager/asyncjob.py", line 100, in cb_wrapper
>     callback(asyncjob, *args, **kwargs)
>   File "/usr/share/virt-manager/virtManager/createinterface.py", line 1134, in
> do_install
>     self.interface.install(meter, create=activate)
>   File "/usr/share/virt-manager/virtinst/Interface.py", line 258, in install
>     raise RuntimeError(errmsg)
> RuntimeError: Could not create interface: internal error failed to create
> (start) interface br1: failed to execute external program - Running 'ifup br1'
> failed with exit code 1: 
> Determining IP information for br1... failed; no link present.  Check cable?
> ===
> 
> I notice that if I have no ethernet cable plugged in so that WiFi is my only
> connection, and I have a ping running while I do this, the ping starts
> returning the below message shortly after I click Finish. I do not have
> network access again until I use NetworkManager Applet to reconnect to my
> wireless router.
> ping: sendmsg: Network is unreachable
> 
> I also tried a bit of fixing on my own. I edited
> /usr/share/virt-manager/virtinst/Interface.py and put a time.sleep(30) just
> before the iface.create(0) that fails, and I reconnected to the router during
> that 30 second pause (and ping started working again), but the interface adder
> just failed with "Failed to create virtual interface" instead. I have since
> restored Interface.py to the original version.
> 
> Does anyone have any idea how I can get this to work? Or, is there a different
> procedure I should follow to bridge my VM to WiFi? Any help is appreciated.
> 

Whatever the issue is, it's unlikely in virt-manager. WRT wireless bridging, I
was always under the impression it doesn't 'just work'.

Some googling pointed to debian instructions here:
https://wiki.debian.org/BridgeNetworkConnections#Bridging_with_a_wireless_NIC

I'd recommend trying to get it working outside of libvirt/virt-manager, just
using native distro config files. If you can get it working there, then we
might be missing a step in libvirt or virt-manager.

- Cole