Re: [libvirt-users] Network interface name of guest via python API

On 03/19/2018 11:46 AM, Dennis Jacobfeuerborn wrote: > Hi, > I'm trying to get some basic data from running guests on a libvirt HV > but one thing I'm missing is the name of the network interfaces of the > guests. I can get the MAC address from the XML but there seems to be no > function to actually get the name of the interface. > > The only function that comes close is this one: > https://libvirt.org/html/libvirt-libvirt-domain.html#virDomainInterfaceAd... > > This function requires a parameter that I don't really have enough > information about. Which parameter is that? flags? That seems fairly thoroughly explained in the documentation you pointed at.

> What is the best way to enumerate a guests interfaces including the name? Assuming you mean the name of the interface *as it appears to the guest*... Since the host can't directly know the names of devices on the guest, the only way you can learn this is with cooperation from the OS running on the guest. One way of getting that cooperation is to make sure the guest is running the qemu guest agent (and that libvirt's domain config has the proper serial channel configured), then virDomainInterfaceAddresses() with the VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_AGENT flag will return entries that contain the interface name as it appears to the guest (the other modes of virDomainInterfaceAddresses will show the names of the tap devices on the *host*, not of the interfaces in the guest). You can check if your guests are running the qemu guest agent (and try out the virDomainInterfaceAddresses() API at the same time) with this shell command (run as root on the host): virsh domifaddr $guestname --source agent Here is info in the libvirt wiki about installing / configuring the qemu guest agent: https://wiki.libvirt.org/page/Qemu_guest_agent (I just checked on a Fedora 27 guest that I previously defined with virt-manager to use spice for video, I found that virt-manager had automatically added the necessary serial channel device ("org.qemu.guest_agent.0"), and that the Linux kernel in the guest automatically noticed that and setup a guest agent in the guest. It may (will) take more work to get the guest agent working for other guest OSes, e.g. Windows.)