[libvirt-users] Questions regarding migration from QEMU to libvirt

Rodrigo Siqueira
Wed, 03 Oct 2018 16:04:50 -0000

Hi,

My colleagues and I have a set of scripts that we use to automate our
daily tasks related to the Linux Kernel. As a result, most of our code
relies on the QEMU features; and recently we decided use libvirt instead
of QEMU. However, we have some questions, and I would like to know if
someone could help us. Follows:

1) Import our QEMU images with virsh

Currently, we import the QEMU VMs with virt-install.

Is it possible to automatically discover the distro variant of a QEMU
image in order to use it in the “--os-variant” option?

Here is how we register a VM:
https://github.com/rodrigosiqueira/kworkflow/pull/23/files#diff-70617d452b008bc71362804d54032f24R113

2) The requirement of sudo to create a network

When we register our VM, we want to keep the ssh working well. However,
every time we register a VM we create a new network bridge as a result
it requires sudo. Is it possible to avoid this? Or at least make this a
single action?

Here is how we handled this:
* The code for register:
https://github.com/rodrigosiqueira/kworkflow/pull/23/files#diff-70617d452b008bc71362804d54032f24R113
* The configuration file that we adopted as a default:
https://github.com/rodrigosiqueira/kworkflow/pull/23/files#diff-d8c16482496875afc0d37b181487ae46R1

3) When using libvirt it changes the owner of our image

If we try to use libvirt, it changes the ownership of our QEMU images
(root). We fixed it by changing the file “/etc/libvirt/qemu.conf”, and
switch the option dynamic_ownership to “0”. What is the impact of that
change? Is it dangerous? There is a way to avoid this change?

Finally, here is the full code of the libvirt part:
https://github.com/rodrigosiqueira/kworkflow/pull/23/files

Thanks
Best Regards

--
Rodrigo Siqueira
http://siqueira.tech
Graduate Student
Department of Computer Science
University of São Paulo