Configuring bridges to use with KVM

[carlopmart]

On 07/12/2010 06:17 PM, Serge E. Hallyn wrote:
> Quoting carlopmart (carlopmart at gmail.com):
>> Hi all,
>>
>>    I have a problem with an ubuntu lucid 10.04 server used for KVM virtualization. My
>> problem appears when I try to configure an "empty" bridge in /etc/network/interfaces
>> file. For example, with a RedHat based distro (RHEL, CentOS) I can create a config
>> file ifcfg-br20 like this:
>>
>> DEVICE=br20
>> TYPE=Bridge
>> ONBOOT=yes
>> DELAY=0
>> STP=off
>> NM_CONTROLLED=no
>>
>>    and then network startup script creates an empty bridge without bind any physical
>> interface. I have tried same procedure to configure several empty bridges under
>> ubuntu without luck:
>>
>> auto intprodif
>> iface intprodif inet static
>> 	bridge_stp off
>> 	bridge_fd 9
>> 	bridge_hello 2
>> 	bridge_maxage 12
>>
>>    When i try to start this bridge with "ifup intprodif" command returns me this error:
>>
>> carlos at silmaril:~$ sudo ifup intprodif
>> Don't seem to be have all the variables for intprodif/inet.
>> Failed to bring up intprodif.
>>
>>    How can I define an empty bridge without binding any physical interface into it??
>>
>>    Many thanks.
>
> man 5 interfaces says that for 'inet static', the following are required:
> 	address
> 	netmask
>
> Add those and see if it still complains?
>
> -serge
>

Thanks Serge. I have changed static to manual and ... nothing happens. See:

auto intprodif
iface intprodif inet manual
	bridge_stp off
	bridge_fd 9
	bridge_hello 2
	bridge_maxage 12

  .. and when I execute "ifup intprodif":

carlos at silmaril:~$ sudo ifup intprodif
Restarting openntpd: ntpd.
ssh stop/waiting
ssh start/running, process 8467

   .. doesn't returns any error, but if I execute "brctl show":

  carlos at silmaril:~$ brctl show
bridge name	bridge id		STP enabled	interfaces
carlos at silmaril:~$

   ... bridge doesn't exists ... Any idea???


-- 
CL Martinez
carlopmart {at} gmail {d0t} com