Re: Predictable and consistent net interface naming in guests

On Mon, Oct 31, 2022 at 04:32:27PM +0200, Edward Haas wrote: > Hi Igor and Laine, > > I would like to revive a 2 years old discussion [1] about consistent network > interfaces in the guest. > > That discussion mentioned that a guest PCI address may change in two cases: > - The PCI topology changes. > - The machine type changes. > > Usually, the machine type is not expected to change, especially if one > wants to allow migrations between nodes. > I would hope to argue this should not be problematic in practice, because > guest images would be made per a specific machine type. > > Regarding the PCI topology, I am not sure I understand what changes > need to occur to the domxml for a defined guest PCI address to change. > The only think that I can think of is a scenario where hotplug/unplug is > used, > but even then I would expect existing devices to preserve their PCI address > and the plug/unplug device to have a reserved address managed by the one > acting on it (the management system). > > Could you please help clarify in which scenarios the PCI topology can cause > a mess to the naming of interfaces in the guest? > > Are there any plans to add the acpi_index support? This was implemented a year & a half ago https://libvirt.org/formatdomain.html#network-interfaces though due to QEMU limitations this only works for the old i440fx chipset, not Q35 yet.

With regards, Daniel