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 <2695bd53d...@ewoof.net> writes: > On 13 Feb 2024 18:10 +0100, from fnat...@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/us...@lists.libvirt.org/; > subscription is mailto:users-j...@lists.libvirt.org. Good suggestion! I will do this. Many Thanks and Best Regards, Felix -- Felix Natter
