Re: [libvirt] [PATCH 6/7] conf: output actual netdev status in <interface> XML

[D] <interface type='network'> <source network='testnet' portgroup='admin'/> <actual type='direct'> <source dev='p4p1_0' mode='bridge'/> <bandwidth> <inbound average='1000' peak='5000' burst='1024'/> <outbound average='128' peak='256' burst='256'/> </bandwidth> </actual> <target dev='macvtap0'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> This was never exposed outside of libvirt though, because I thought it would be too awkward for a management application to need to look in two places for the same information, but I also wasn't sure that it would be okay to overwrite the config info (in this case "<source network='testnet' portgroup='admin'/>") with the actual runtime info (everything inside <actual> above).

Now the time has come that this information must be made available to management applications (in particular, so that a network "plugged" hook will have full information about the device that is being plugged in), so it's time to take the leap and decide that it is acceptable for the config info to be replaced with actual runtime state (but *only* when reporting domain live status, *not* when saving state in /etc/libvirt/qemu/$domain.xml - that remains the same so that there is no loss of information). That is what this patch does. With this patch applied, the output of "virsh dumpxml $domain" when the domain is running will contain something like this: [E] <interface type='direct'> <source dev='p4p1_0' mode='bridge'/> <bandwidth> <inbound average='1000' peak='5000' burst='1024'/> <outbound average='128' peak='256' burst='256'/> </bandwidth> <target dev='macvtap0'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> In effect, everything that is internally stored within <actual> is moved up a level to where a management application will expect it. This means that the management application will only look in a single place to learn - the type of interface in use, the name of the physdev (if relevant), the <bandwidth>, <vlan>, and <virtualport> settings in use. The potential downside is that a management app looking at this output will not see that the physdev 'p4p1_0' was actually allocated from the network named 'testnet', or that the bandwidth numbers were taken from the portgroup 'admin'. However, if they are interested in that info, they can always get the "inactive" XML for the domain.