Subject: Re: [Vserver] Re: IP alias limitation
From: Mike O'Connor <vserver@pineview.net>
Date: Sat, 28 Jul 2007 11:48:42 +0930

Has this limitation been overcome as yet and if it has what version of
tools and kernel is needed ?

Thanks
Mike

Herbert Poetzl wrote:
> On Wed, Aug 23, 2006 at 10:22:19PM +0200, Bruno wrote:
>   
>> On Wednesday 23 August 2006 22:08, Kathy Kost wrote:
>>     
>>> Nope.  Once an alias is created, however which way, the system comes up
>>> with a "16 alias max" message.  Don't recall the actual message.  The
>>> vserver would not restart and I had to remove the interfaces and reboot
>>> the entire server.
>>>
>>> Kathy
>>>
>>>       
>>>> Does it help to add ip's with the ip add ... command instead of
>>>> using ifconfig? Aliases are sooo last millennium.
>>>>
>>>>
>>>> /Benny
>>>>         
>
>   
>> The kernel patch has a maximum of IP addresses per network context
>> defined.
>>     
>
>   
>> Context-association of IP addresses is not optimized, thus many
>> addresses cause some overhead when checking if incoming packets may be
>> delivered to a guest. (check if IP is available to a guest)
>>     
>
>   
>> In addition you have 12 bytes allocated per possible IP address: 12 *
>> 16 = 192 bytes (even if guest has just 1 IP assigned to it)
>>     
>
>   
>> For the define limiting the count of IP addresses, see
>> include/linux/vserver/network.h (line 11):
>>     
>
>   
>> @define NB_IPV4ROOT 16
>>     
>
>   
>> Note that you may need to check what header the userspace tools get
>> compiled against.
>>     
>
> also note that this limitation will go away pretty soon :)
>
> best,
> Herbert
>
>   
>> Bruno
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>>     
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