Easy way to convert a libvirt XML configuration to a format Proxmox recognizes?

[abceleung]

(Crosspost from r/Proxmox)

I have a libvirt VM (QEMU/KVM based) that has CPU pinning, PCIe device passthrough, iothread and other optimizations (it is a VFIO gaming VM) in a Fedora host. I will install Proxmox in this machine soon, and I want to recreate the gaming VM inside it.

How do I convert this XML configuration to a format that Proxmox can use? Are all config options in libvirt available in Proxmox?

AFAIK Proxmox does not use libvirt.

 

[leesteken]

AFAIK Proxmox does not use libvirt.

Indeed. libvirt converts the XML to QEMU/KVM command-line arguments when starting a VM. Maybe you can get it to show you the command-line arguments it produces?

Proxmox supports a args: setting in its VM configuration file where you could put any QEMU/KVM command-line argument. However, Proxmox also converts all its other settings and they may interfere. And Proxmox uses a storage layer and PCI(e) device passthrough mapping and othe stuff: https://pve.proxmox.com/pve-docs/pve-admin-guide.html#qm_configuration

It might be best to try to recrease the VM in Proxmox as best as you can and only then see if you needs additional args: for which you can see if libvirt can tell you the command-line arguments. Proxmox designed for enterprise enviroments, so it might not be easy/possible/practical to convert your VM as is. But you might come close by manually adding stuff, if you spend the time (again) to tweak it.

EDIT: Short answer: No, there is no easy way. You can check Proxmox's command-line arguments that is procudes with qm showcmd VM_ID_NUMBER.

 

[abceleung]

Indeed. libvirt converts the XML to QEMU/KVM command-line arguments when starting a VM. Maybe you can get it to show you the command-line arguments it produces?

Proxmox supports a args: setting in its VM configuration file where you could put any QEMU/KVM command-line argument. However, Proxmox also converts all its other settings and they may interfere. And Proxmox uses a storage layer and PCI(e) device passthrough mapping and othe stuff: https://pve.proxmox.com/pve-docs/pve-admin-guide.html#qm_configuration

It might be best to try to recrease the VM in Proxmox as best as you can and only then see if you needs additional args: for which you can see if libvirt can tell you the command-line arguments. Proxmox designed for enterprise enviroments, so it might not be easy/possible/practical to convert your VM as is. But you might come close by manually adding stuff, if you spend the time (again) to tweak it.

EDIT: Short answer: No, there is no easy way. You can check Proxmox's command-line arguments that is procudes with qm showcmd VM_ID_NUMBER.

Thanks for your answer!

I guess I can compare the output of qm showcmd VM_ID_NUMBER (in Proxmox) and virsh domxml-to-native (this converts libvirt configs to QEMU command line) and try to mesh them together. It should work since both Proxmox and libvirt use QEMU.

 

[abceleung]

Indeed. libvirt converts the XML to QEMU/KVM command-line arguments when starting a VM. Maybe you can get it to show you the command-line arguments it produces?

Proxmox supports a args: setting in its VM configuration file where you could put any QEMU/KVM command-line argument. However, Proxmox also converts all its other settings and they may interfere. And Proxmox uses a storage layer and PCI(e) device passthrough mapping and othe stuff: https://pve.proxmox.com/pve-docs/pve-admin-guide.html#qm_configuration

It might be best to try to recrease the VM in Proxmox as best as you can and only then see if you needs additional args: for which you can see if libvirt can tell you the command-line arguments. Proxmox designed for enterprise enviroments, so it might not be easy/possible/practical to convert your VM as is. But you might come close by manually adding stuff, if you spend the time (again) to tweak it.

EDIT: Short answer: No, there is no easy way. You can check Proxmox's command-line arguments that is procudes with qm showcmd VM_ID_NUMBER.

BTW, what happens if Proxmox settings and args: settings overlap? Which one takes priority?