Re: [libvirt] [BUG] When PLUG a bridge interface to an active VM, the generated LIVE and CONFIG mac address are different

On Tue, Aug 27, 2019 at 02:13:28PM +0200, Michal Privoznik wrote: > On 8/22/19 10:43 AM, Xu Yandong (Yandong Xu) wrote: >> Hi, >> >> When plug a bridge interface to an active VM with both LIVE AND >> CONFIG flags, >> libvirt generate different mac address to LIVE and CONFIG instance, >> so After >> I reboot the VM, DHCP server doesn't assign the same IP address to >> the new >> bridge interface. >> > > This is kind of expected. In general, live and inactive XMLs can be > significantly different. Well, if the live and inactive XMLs have sufficiently diverged, then I don't see the point of calling AttachDevice with both AFFECT_LIVE and AFFECT_CONFIG - you might as well use two different API calls. However for a guest with the definitions in sync, quietly accepting a both flags while attaching a device with different MAC addresses (so essentially two different devices) feels wrong. > And I guess it's out of libvirt's scope to try and autofill missing > data in such way that fits both libe and inactive XMLs. For instance, > a PCI address can be taken/free in live XML because of > hotplug/hotunplug but that might not be the case for inactive XML. > Should libvirt try and find a slot that suits both XMLs? > That possibly might be out of scope, but autofilling the mac address as early as virDomainNetDefParseXML also is not ideal.