OpenVZ Forum


Home » Mailing lists » Devel » Re: [patch 2/6] [Network namespace] Network device sharing by view
Re: [patch 2/6] [Network namespace] Network device sharing by view [message #4155 is a reply to message #4148] Fri, 30 June 2006 07:45 Go to previous messageGo to previous message
Andrey Savochkin is currently offline  Andrey Savochkin
Messages: 47
Registered: December 2005
Member
Hi Jamal,

On Thu, Jun 29, 2006 at 08:15:52PM -0400, jamal wrote:
> On Fri, 2006-30-06 at 09:07 +1200, Sam Vilain wrote:
[snip]
> > We plan to have them separate - so for
> > that to work, each network namespace could have an arbitrary "prefix"
> > that determines what the interface name will look like from the outside
> > when combined. We'd have to be careful about length limits.
> >
> > And guest0-eth0 doesn't necessarily make sense; it's not really an
> > ethernet interface, more like a tun or something.
> >
>
> it wouldnt quiet fit as a tun device. More like a mirror side of the
> guest eth0 created on the host side
> i.e a sort of passthrough device with one side visible on the host (send
> from guest0-eth0 is received on eth0 in the guest and vice-versa).
>
> Note this is radically different from what i have heard Andrey and co
> talk about and i dont wanna disturb any shit because there seems to be
> some agreement. But if you address me i respond because it is very
> interesting a topic;->

I do not have anything against guest-eth0 - eth0 pairs _if_ they are set up
by the host administrators explicitly for some purpose.
For example, if these guest-eth0 and eth0 devices stay as pure virtual ones,
i.e. they don't have any physical NIC, host administrator may route traffic
to guestXX-eth0 interfaces to pass it to the guests.

However, I oppose the idea of automatic mirroring of _all_ devices appearing
inside some namespaces ("guests") to another namespace (the "host").
This clearly goes against the concept of namespaces as independent realms,
and creates a lot of problems with applications running in the host, hotplug
scripts and so on.

>
> > So, an equally good convention might be to use sequential prefixes on
> > the host, like "tun", "dummy", or a new prefix - then a property of that
> > is what the name of the interface is perceived to be to those who are in
> > the corresponding network namespace.
> >
> > Then the pragmatic question becomes how to correlate what you see from
> > `ip addr list' to guests.
>
> on the host ip addr and the one seen on the guest side are the same.
> Except one is seen (on the host) on guest0-eth0 and another is seen
> on eth0 (on guest).

Then what to do if the host system has 10.0.0.1 as a private address on eth3,
and then interfaces guest1-tun0 and guest2-tun0 both get address 10.0.0.1
when each guest has added 10.0.0.1 to their tun0 device?

Regards,

Andrey
 
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Previous Topic: Re: [Vserver] Re: Container Test Campaign
Next Topic: porting stable patch to higher kernel versions
Goto Forum:
  


Current Time: Sun Aug 03 17:13:26 GMT 2025

Total time taken to generate the page: 0.78218 seconds