[libvirt] [PATCH] Support reporting live interface IP/netmask.

[David Lutterkort]

On Mon, 2009-10-05 at 17:34 +0100, Daniel P. Berrange wrote:
> With the domain XML format, we did have a few abortive attempts at
> indicating in the live XML, whether an attribute was from the 
> persistent config, vs dynamically added to live config, but it all
> ended up as rather a mess.

Here's a concrete example where this leads to headscratching, at a
minimum, with the netowrk configs. When the live XML contains

        <protocol family="ipv4">
          <dhcp/>
          <ip address="192.168.0.5" prefix="24"/>
          <route gateway="192.168.0.1"/>
        </protocol>
        
you at least think that the interface is configured to use DHCP, and
currently has the indicated address. Of course, if we ever poke around
to see if the interface _currently_ gets its address from DHCP, we have
no way to indicate that anymore, since we would indicate 'configured to
use DHCP' and 'currently gets its address from DHCP' in exactly the same
way. Also, US $5 to anybody who knows whether the <route/> tag above
says 'is configured to use that gateway' or 'routing is through that
gateway right now'.

To belabor this point, when the live XML says

        <protocol family="ipv4">
          <ip address="192.168.0.5" prefix="24"/>
          <ip address="192.168.0.6" prefix="24"/>
        </protocol>
        
it's completely unclear what addresses are in the config files (maybe
both?) and which ones are actually assigned to the interface right now.

David