Re: simple virt-manager setup
Dear Michael,
many thanks for the detailed answer, I will keep all of this for
reference as I learn about libvirt!
Am I right that it is not possible to backup/restore VMs
using virt-manager GUI (on Debian12)? ChatGPT suggested this
is possible, but confused this with Hyper-V I think ;-)
So my best bet for backup/restore of data+config of a VM is to script
libvirt or use an existing bash script [1]? (Can you recommend one?)
Or is there a ProxMox vzdump equivalent for Debian?
[1] https://ostechnix.com/export-import-kvm-virtual-machines-linux/
Further answers inline.
Michael Kjörling <2695bd53d63c@ewoof.net> writes:
> On 13 Feb 2024 18:10 +0100, from fnatter@gmx.net (Felix Natter):
>> regarding virt-manager (qemu/kvm):
>>
>> Can I safely choose the "NAT" network type for a new VM
>> in virt-manager (Debian12):
>
> Yes. Doing so should create a new network interface named virbr[0-9]
> and assign an IPv4 address range to it which will be used for VM
> purposes.
>
>> Can I safely say yes to
>> "Do you want to bring it up?"? (is it undoable?)
>
> Yes, it is undoable. You can either use virt-manager -> connection
> details -> virtual networks (select the network and then click the
> stop button below the list) or you can use
>
> $ sudo virsh net-list --all
>
> $ sudo virsh net-destroy network-name
>
> Despite the scary action name, virsh net-destroy only stops the
> network; it doesn't actually deconfigure it. (For that, you use virsh
> net-undefine. There is also virsh net-autostart.) See the virsh(1) man
> page.
>
> If you want to be extra certain, you can dump your firewall rules just
> before you bring up the KVM network so that you can restore them
> without a reboot.
>
>
>> If I choose NAT, can multiple VMs connect to each other
>> and with the host?
>
> I know that VMs can talk to the host through a KVM NAT interface. I
> haven't tested whether they can talk to each other, but I would expect
> so.
In my previous installation I used WLAN as well, so my understanding is
that I could not have used type=bridge, and I did communicate between vms
(mounting nfs shares), so I think this _should_ work.
> If you are using nftables on the host, you might find my blog post at
> https://michael.kjorling.se/blog/2022/linux-kvm-host-nftables-guest-networking/
> helpful if VMs can't talk to the network. I have received some
> feedback that there are easier solutions, but try as I did at the time
> I couldn't find them, and what I wrote up there Works For Me (tm).
I did not change anything in the firewall.
>> (I would like to avoid making many changes that I don't understand
>> to a productive server)
>
> Very understandable, and prudent.
*thumbup*
> You may want to consider subscribing to
> https://lists.libvirt.org/archives/list/users@lists.libvirt.org/;
> subscription is mailto:users-join@lists.libvirt.org.
Good suggestion! I will do this.
Many Thanks and Best Regards,
Felix
--
Felix Natter
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