Re: [libvirt] [question]Is there a good way to get the mac of guest interface after I attached it to a guest

On Fri, Jan 24, 2014 at 10:37:20AM +0800, Sheldon wrote: > Now I working on a new KVM management tool base on html5 and libvirt > > we will support a REST API for detach and attach guest interface. > > we want to use mac as the identifier of the network interface. > > That meas we should get the mac after the user create a interface. > also other people may be doing the exact same thing at the exact same > time to create a interface. > > > Here are the demo codes: > > dom = self._get_vm(vm) > xml = """ > <interface type='network'> > <source network='default'/> > </interface> > """ > dom.attachDeviceFlags(xml, libvirt.VIR_DOMAIN_AFFECT_CURRENT) > # now I want to get the mac, how to get it? > You have to parse the XML back and find it. > I have check libvirt use this code to generate a mac address. > does libvirt can gurantee that the MAC address generated is unique? > No, as mentioned in the second subthread, the XML you provided is incomplete and can cause address clashing. So te best answer to your question in $SUBJ would be "generate it yourself and add it to the XML before attaching".

Martin > void virMacAddrGenerate(const unsigned char prefix[VIR_MAC_PREFIX_BUFLEN], > virMacAddrPtr addr) > { > addr->addr[0] = prefix[0]; > addr->addr[1] = prefix[1]; > addr->addr[2] = prefix[2]; > addr->addr[3] = virRandomBits(8); > addr->addr[4] = virRandomBits(8); > addr->addr[5] = virRandomBits(8); > } > libvirt also use the KVM prefix as default as it's in the privately > administered range: > 52:54:00:XX:XX:XX > > > > -- > Thanks and best regards! > > Sheldon Feng(冯少合)&lt;shaohef(a)linux.vnet.ibm.com&gt; > IBM Linux Technology Center > > -- > libvir-list mailing list > libvir-list(a)redhat.com > https://www.redhat.com/mailman/listinfo/libvir-list