# Cannot create bridge interface

## leonchik1976

I'm trying to create a bridge interface with "Virtual Machine Manager", and no matter what i try, is gives me the following error

Error creating interface: 'Could not define interface: this function is not supported by the connection driver: virInterfaceDefineXML'

```
Traceback (most recent call last):

  File "/usr/share/virt-manager/virtManager/asyncjob.py", line 89, in cb_wrapper

    callback(asyncjob, *args, **kwargs)

  File "/usr/share/virt-manager/virtManager/createinterface.py", line 1145, in do_install

    self.interface.install(meter, create=activate)

  File "/usr/share/virt-manager/virtinst/interface.py", line 258, in install

    raise RuntimeError(_("Could not define interface: %s") % str(e))

RuntimeError: Could not define interface: this function is not supported by the connection driver: virInterfaceDefineXML

```

any help would appreciated, thanks  :Smile: 

[Moderator edit: added [code] tags to preserve output layout. -Hu]

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## mike155

Hi leonchik1976,

you could try to set up the bridge manually -- in order to see whether the problems come from your kernel, your configuration tools or from your "Virtual Machine Manager":

```
tunctl -u kvm -t tap0

tunctl -u kvm -t tap1

brctl addbr br0

brctl addif br0 tap0

brctl addif br0 tap1

brctl show br0
```

Mike

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## eccerr0r

As far as I know, VMM/libvirt/qemu can't create bridges, nor would it be proper for it to create bridges to nowhere.  So yes, you have to make the bridge outside of VMM.

It can create an exit/tap off the bridge however, which is what I suppose was the intent of the option in VMM.

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## bbgermany

 *eccerr0r wrote:*   

> As far as I know, VMM/libvirt/qemu can't create bridges, nor would it be proper for it to create bridges to nowhere.  So yes, you have to make the bridge outside of VMM.
> 
> It can create an exit/tap off the bridge however, which is what I suppose was the intent of the option in VMM.

 

Hi, this is correct. You need to configure your bridge in /etc/conf.d/net first and start it, with the tap interface already connected to the bridge, before running vmm and creating a new vm.

greets, bb

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