Prior to commit 7d5bf484747 (first appearing in libvirt 1.2.2), the status XML of a domain's interface was missing a lot of important information; mainly it just output the config of the interface, plus the name of the tap device and qemu device alias. Commit 7d5bf484747 changed the status XML to include many important bits of information that were required to make network "hook" scripts useful - bandwidth information, vlan tag, the name of the bridge (or physical device in the case of macvtap) that the tap/macvtap device was attached to - the commit log for 7d5bf484747 has a very detailed explanation of the change. For quick reference - in the example given there, prior to the change, status XML looked like figure [C]: <interface type='network'> <source network='testnet' portgroup='admin'/> <target dev='macvtap0'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> and after the change, it looked like figure [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> You'll notice that bandwidth info, physdev, and macvtap mode have been added, but the network and portgroup names are now missing - I didn't think that this information was of any use once the needed bandwidth/vlan/etc config had been pulled from the network/portgroup. I was wrong. A few months after that change a user on IRC asked what happened to portgroup in the status XML and described how he used it (more or less as a tag to decide what external information to use in a hook script that was run at startup/migration time - see http://wiki.libvirt.org/page/OVS_and_PVLANS ). At that time I planned to make a patch to re-add portgroup, but life intervened as that was just prior to a transatlantic move involving several weeks of "vacation". During this time I somehow forgot to make the patch, and also mistakenly remembered that I *had* made it. Subsequent to this, as a part of mprivozn's work to add support for network-specific hooks, I did re-add the output of the network name in status XML, but once again completely forgot about portgroup. This was in commit a3609121 (first appearing in libvirt 1.2.11). This made the status XML from the above example look like this: <interface type='direct'> <source network='testnet' 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> *This* patch just adds the portgroup back to the status XML, so the same example interface will look like this: <interface type='direct'> <source network='testnet' portgroup='admin' 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> The result is that the status XML now contains all information about how the interface is setup (bandwidth, physical device, tap device, etc), in addition to pointers to its origin (the network and portgroup). --- I had previously asked about this topic here: https://www.redhat.com/archives/libvir-list/2014-June/msg00416.html but then forgot to follow up on it... src/conf/domain_conf.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 8600eff..d870bb6 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -17591,14 +17591,18 @@ virDomainActualNetDefContentsFormat(virBufferPtr buf, if (def->type == VIR_DOMAIN_NET_TYPE_NETWORK && !inSubelement) { /* When we're putting our output into the <actual> * subelement rather than the main <interface>, the - * network name isn't included in the <source> because the - * main interface element's <source> has the same info - * already. If we've been called to output directly into - * the main element's <source> though (the case here - - * "!inSubElement"), we *do* need to output the network - * name, because the caller won't have done it). + * network name and portgroup don't need to be included in + * the <source> here because the main interface element's + * <source> has the same info already. If we've been + * called to output directly into the main element's + * <source> though (the case here - "!inSubElement"), we + * *do* need to output network/portgroup, because the + * caller won't have done it). */ - virBufferEscapeString(buf, " network='%s'", def->data.network.name); + virBufferEscapeString(buf, " network='%s'", + def->data.network.name); + virBufferEscapeString(buf, " portgroup='%s'", + def->data.network.portgroup); } if (actualType == VIR_DOMAIN_NET_TYPE_BRIDGE || actualType == VIR_DOMAIN_NET_TYPE_NETWORK) {