[Devel] Re: Network virtualization/isolation

[Eric W. Biederman]

I do not want to get into a big debate on the merits of various
techniques at this time.  We seem to be in basic agreement
about what we are talking about.

There is one thing I think we can all agree upon.
- Everything except isolation at the network device/L2 layer, does not
  allow guests to have the full power of the linux networking stack.

- There has been a demonstrated use for the full power of the linux
  networking stack in containers..

- There are a set of techniques which look as though they will give
  us full speed when we do isolation of the network stack at the
  network device/L2 layer.

Is there any reason why we don't want to implement network namespaces
without the full power of the linux network stack?

If there is a case where we clearly don't want the full power of the
linux network stack in a guest but we still need a namespace we can
start looking at the merits of the alternatives.

> What is this new paradigm you are talking about ?

The basic point is this.  The less like stock linux the inside of a
container looks, and the more of a special case it is the more
confusing it is.  The classic example is that for a system container
routing packets between containers over the loopback interface is
completely unexpected.


> There is not extra networking data structure instantiation in the
> Daniel's L3.
Nope just an extra field which serves the same purpose.

>> - Bind/Connect/Accept filtering.  There are so few places in
>>   the code this is easy to maintain without sharing code with
>>   everyone else.
>
> For isolation too ? Can we build network migration on top of that ?

As long as you can take your globally visible network address with you
when you migrate you can build network migration on top of it.  So yes
bind/accept filtering is sufficient to implement migration, if you are
only using IP based protocols.

Eric
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