Re: [PATCH] Virtual ethernet tunnel

[Pavel Emelianov <xemul@openvz.org>]

Daniel Lezcano wrote:
> Pavel Emelianov wrote:
>>>> I did this at the very first version, but Alexey showed me that this
>>>> would be wrong. Look. When we create the second device it must be in
>>>> the other namespace as it is useless to have them in one namespace.
>>>> But if we have the device in the other namespace the RTNL_NEWLINK
>>>> message from kernel would come into this namespace thus confusing ip
>>>> utility in the init namespace. Creating the device in the init ns and
>>>> moving it into the new one is rather a complex task.
>>>>         
>>> Pavel,
>>>
>>> moving the netdevice to another namespace is not a complex task. Eric
>>> Biederman did it in its patchset ( cf.  http://lxc.sf.net/network )
>>>     
>>
>> By saying complex I didn't mean that this is difficult to implement,
>> but that it consists (must consist) of many stages. I.e. composite.
>> Making the device right in the namespace is liter.
>>
>>  
>>> When the pair device is created, both extremeties are into the init
>>> namespace and you can choose to which namespace to move one extremity.
>>>     
>>
>> I do not mind that.
>>  
>>> When the network namespace dies, the netdev is moved back to the init
>>> namespace.
>>> That facilitate network device management.
>>>
>>> Concerning netlink events, this is automatically generated when the
>>> network device is moved through namespaces.
>>>
>>> IMHO, we should have the network device movement between namespaces in
>>> order to be able to move a physical network device too (eg. you have 4
>>> NIC and you want to create 3 containers and assign 3 NIC to each of
>>> them)
>>>     
>>
>> Agree. Moving the devices is a must-have functionality.
>>
>> I do not mind making the pair in the init namespace and move the second
>> one into the desired namespace. But if we *always* will have two ends in
>> different namespaces what to complicate things for?
>>   
> Just to provide a netdev sufficiently generic to be used by people who
> don't want namespaces but just want to do some network testing, like Ben
> Greear does. He mentioned in a previous email, he will be happy to stop
> redirecting people to out of tree patch.

This patch creates booth devices in the init namespace. That's what
you want, isn't it? When we have the namespaces we will be able to
create the pair with booth ends in the init namespace - just do not
specify the namespace id to create the 2nd end in and the driver will
leave it int the init one.

> https://lists.linux-foundation.org/pipermail/containers/2007-April/004420.html
> 
> 
>> Thanks,
>> Pavel
>>
>>   
> 
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