[netcf-devel] [libvirt] [RFC] Reporting host interface status/statistics via netcf/libvirt, and listing active vs. inactive interfaces

[Jonas Eriksson]

On Wed, Jun 17, 2009 at 01:27:14PM -0700 David Lutterkort wrote:
> or forever hold your peace.

While talking about the relax-ng schema, I would like to
again raise my question earlier raised at the netcf-devel-list
in order to get some input from the libvirt developers on this
matter as well.

I am a bit critical to the policy restrictions of the current
incarnation of the netcf API. Currently, a interface (or
connection) has to have an IP address and a bridge has to have
one or more interfaces attached to it.

Not having the IP address restriction may collide head on with
the connection-approach for some, as a connection probably have
to be addressable. I however argue that this severly limits the
uses for netcf, say for example to only bridge two interfaces
without caring (and perhaps not wanting) to be something other
then a package forwarder and not care about IP-address
collisions. And in another case, the addressing is done using
something other then IP.

For the bridges without added interfaces, an example is libvirt
that have these private networks that I don't think I have to go
in to in detail.

My strongest point in both cases is that both restrictions is
policy-driven. If for example an option in a configuration file
for an interface is not recognized by netcf, it may be simply
ignored and later merged back in to the configuration if this is
updated through netcf. The restrictions in IP-addresses and
bridge members can however make an existing configuration clash
with netcf. In the end, there is nothing that stops end
applications to implement this policy if required.

As said, I raised this question on netcf-devel, and David and I
have been having some back-and-forth about this [1]. I also
promised to raise this question here as per request about a month
ago.

What are the views of the libvirt community? Is netcf planned to
be used for the "isolated" libvirt-networks? Will there be a case
where a forwarding bridge perferably would lack an IP address?
Other thoughts?

Best regards,
Jonas

[1] https://fedorahosted.org/pipermail/netcf-devel/2009-May/thread.html
    https://fedorahosted.org/pipermail/netcf-devel/2009-June/000012.html
    https://fedorahosted.org/pipermail/netcf-devel/2009-June/000013.html

--
Jonas Eriksson
Consultant at AS/EAB/FLJ/IL
Combitech AB
Dlvsjv, Sweden