[libvirt-users] Bridging Wireless Cards for KVM

Joshua McKee josjunk at gmail.com
Sun Aug 11 02:33:17 UTC 2013


Sorry, I accidentally hit send before I was done. Here's the finished
message:

Thanks! Unfortunately, I am running into the following issue when
attempting to use the generic ethernet configuration:

$ virsh -c qemu:///system create /tmp/generic.xml
error: Failed to create domain from /tmp/generic.xml
error: internal error process exited while connecting to monitor: kvm:
-netdev tap,id=hostnet0: could not configure /dev/net/tun: Operation not
permitted
kvm: -netdev tap,id=hostnet0: Device 'tap' could not be initialized

This is the network part of my xml file:

...
<devices>
   <interface type="ethernet"/>
   ...
   <interface type="ethernet'>
      <target dev="tap0"/>
      <script path='/etc/qemu-ifup'/>
   </interface>
   ...
</devices>
...

In my /etc/libvirt/qemu.conf file I have the following set:

user = "root"
group ="root"
dynamic ownership = 0
clear_emulator_capabilities = 0
cgroup_device_acl = [
    "/dev/null", "/dev/full", "/dev/zero",
    "/dev/random", "/dev/urandom",
    "/dev/ptmx", "/dev/kvm", "/dev/kqemu",
    "/dev/rtc", "/dev/hpet",
    "/dev/net/tun",
]

I am running Ubuntu 12, which does not use SELinux.



On Sat, Aug 10, 2013 at 8:30 PM, Joshua McKee <josjunk at gmail.com> wrote:

> Thanks! Unfortunately, I am running into the following issue when
> attempting to use the generic ethernet configuration:
>
> $ virsh -c qemu:///system create /tmp/generic.xml
> error: Failed to create domain from /tmp/generic.xml
> error: internal error process exited while connecting to monitor: kvm:
> -netdev tap,id=hostnet0: could not configure /dev/net/tun: Operation not
> permitted
> kvm: -netdev tap,id=hostnet0: Device 'tap' could not be initialized
>
> This is the network part of my xml file:
>
> <devices>
>    <interface type="ethernet"/>
>
>
>  ...
>   <devices>
>     <interface type='ethernet'/>
>     ...
>     <interface type='ethernet'>
>       <target dev='vnet7'/>
>       <script path='/etc/qemu-ifup-mynet'/>
>     </interface>
>   </devices>
>   ...
>
>
>
> In my /etc/libvirt/qemu.conf file I have the following set:
>
> user = "root"
> group ="root"
> dynamic ownership = 0
> clear_emulator_capabilities = 0
> cgroup_device_acl = [
>     "/dev/null", "/dev/full", "/dev/zero",
>     "/dev/random", "/dev/urandom",
>     "/dev/ptmx", "/dev/kvm", "/dev/kqemu",
>     "/dev/rtc", "/dev/hpet",
>     "/dev/net/tun",
> ]
>
> I am running Ubuntu 12, which does not use SELinux.
>
>
> On Fri, Aug 9, 2013 at 8:01 AM, Daniel P. Berrange <berrange at redhat.com>wrote:
>
>> On Thu, Aug 08, 2013 at 08:55:27PM -0600, Joshua McKee wrote:
>> > Hi,
>> >
>> > I hope this is the right place to ask this question. I was wondering if
>> > there is a way to set up a KVM VM using an XML document as input into
>> Virsh
>> > that uses bridged networking over a wireless card.
>> >
>> > I understand that wireless cards to not natively support, but I was
>> able to
>> > find a working solution here:
>> > http://blog.ericwhite.ca/articles/2011/04/creating-a-wireless-bridge/.
>>
>> Ok, that's slightly different. The traditional integration with Linux
>> bridge devices is doing ethernet layer bridging - so all protocols
>> like IPv4, IPv6, etc, etc will "just work".
>>
>> What that blog describes is protocol layer bridging, which with those
>> instructions only works for IPv4.
>>
>> Libvirt doesn't have any explicit support for the latter. Though we have
>> thought about implementing it in the virtual network APIs, we've never
>> got around to it.
>>
>> > The issue is, I can use this bridge by calling KVM directly. However, I
>> > cannot figure out how to get this same configuration on an XML file
>> that I
>> > input into Virsh for the creation of a VM.
>> >
>> > My understanding is that libvirt calls KVM/QEMU at some point, but I
>> may be
>> > mistaken.
>>
>> You might be able to get it working using the generic ethernet config
>>
>>    http://libvirt.org/formatdomain.html#elementsNICSEthernet
>>
>> That setup you specify a pre-created TAP device for the VM to use.
>> Of course it is upto you todo the manal config steps described in
>> that blog, so is more tedious from an admin pov.
>>
>>
>> Daniel
>> --
>> |: http://berrange.com      -o-
>> http://www.flickr.com/photos/dberrange/ :|
>> |: http://libvirt.org              -o-
>> http://virt-manager.org :|
>> |: http://autobuild.org       -o-
>> http://search.cpan.org/~danberr/ :|
>> |: http://entangle-photo.org       -o-
>> http://live.gnome.org/gtk-vnc :|
>>
>
>
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