On 9/26/22 15:06, 陈新隆 wrote:

<https://stackoverflow.com/posts/73854544/timeline>

I'm using Kubevirt to manage my virtual machine instances. When I using Kubevirt to create a vm(with two GPUs), kubevirt will generate a libvirt guest domain xml for this vm which includes two GPUs, the domain xml as follow :

|<hostdev mode='subsystem' type='pci' managed='no'> <driver name='vfio'/> <source> <address domain='0x0000' bus='0x83' slot='0x00' function='0x0'/> </source> <alias name='ua-gpu-gpu0'/> <address type='pci' domain='0x0000' bus='0x06' slot='0x00' function='0x0'/> </hostdev> <hostdev mode='subsystem' type='pci' managed='no'> <driver name='vfio'/> <source> <address domain='0x0000' bus='0x84' slot='0x00' function='0x0'/> </source> <alias name='ua-gpu-gpu1'/> <address type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/> </hostdev> |

No one ever edit this domain xml, but these two |hostdev| element disappeared in the domain xml. During this time, I've run the |gpu_burn| command to do a stress test for these two GPUs.

My question is :

* when will libvirtd change the guest domain xml ? * why libvirtd delete these two |hostdev| from domain xml ?

Libvirt does not remove anything from domain XML (except for the elements it does not understand, but this is not the case). My suspicion is that you're looking at live XML instead of inactive XML or vice versa. Libvirt allows guests to be defined (i.e. libvirt manages their inactive definition). However, a guest can be started with wildly different configuration (e.g. without those two <hostdev/>-s). OR, they might have been hot-unplugged. This article can explain more details: https://wiki.libvirt.org/page/VM_lifecycle Michal