Thank you for the reply. I truly appreciate them. I used virt-manager to set up my VMs and manage them on a daily basis. After reading your responses I used the commands below to gather some information: $sudo virsh net-list --all Name State Autostart Persistent ---------------------------------------------- default inactive no yes $sudo virsh net-info default Name: default UUID: some-number Active: no Persistent: yes Autostart: no Bridge: virbr0 I thought it was interesting that the default network was not marked to restart at boot and changed that: $sudo virsh net-autostart default Network default marked as autostarted Then due to its inactive status, I thought it would be a good idea to start it with: $sudo virsh net-start default Network default started Of note, even though the default network was marked as inactive as above, it was working. In other words, I was able to reach the VMs, which are part of that network, even before the `virsh net-start default` command. Nothing seemed to break with the command either, and everyting still seemed to work afterwards. $sudo virsh net-info default Name: default UUID: some-number Active: yes Persistent: yes Autostart: yes Bridge: virbr0 I would really appreciate if you can confirm that this is the desired state for my network for the purposes I discussed previously. I apologize if I am oversimplifying things here, it is because of my lack of in-depth understanding the appropriate set up. Thanks, Hakan On 22/01/24 05:30PM, Laine Stump wrote: > > > On 1/24/22 4:35 AM, Martin Kletzander wrote: > > On Fri, Jan 21, 2022 at 08:42:58AM -0600, Hakan E. Duran wrote: > > > Hi, > > > > > > I would like some help to troubleshoot the problem I have been having > > > lately with my VM host, which contains 5 VMs, one of which is for > > > pi-hole, unbound services. It has been a relatively common occurrence in > > > the last few weeks for me to find that the host machine has lost its > > > network when I get back home from work. Restoring the VM/VMs do not fix > > > the problem, the host needs to be restarted for a fix, otherwise there > > > is both loss of name resolution, as well as an internet connection; I > > > cannot ping even IPs such as 8.8.8.8. Since I use the pi-hole VM as > > > the DNS > > > server for my LAN, this means that my whole LAN gets disconnected from > > > internet, until the host machine is rebooted. The host machine has a > > > little complicated network setup: the two gigabit connections are bonded > > > and bridged to the VMs; however this set up has been serving me so well > > > for several years now. The problem, on the other hand, appeared a few > > > weeks ago. This doesn't happen every day but often enough to be annoying > > > and disruptive for my family. > > > > > > > Always good to check what has changed those weeks ago, but I understand > > it is difficult to find out what you were updating and where. > > > > > My question is, how can I troubleshoot this problem and figure out > > > whether it is truly due to network bridging somehow collapsing or not? I > > > tried to find some log files but all I could find were the > > > /var/log/libvirt/qemu/$VM files, and the particular log file for the > > > pi-hole > > > VM reported the following lines; however, I am not sure if they are > > > associated with a real crash or just due to shutting down and restarting > > > the host (please excuse the word-wrapping): > > > > > > char device redirected to /dev/pts/2 (label charserial0) > > > qxl_send_events: spice-server bug: guest stopped, ignoring > > > 2022-01-20T23:41:17.012445Z qemu-system-x86_64: terminating on > > > signal 15 from pid 1 (/sbin/init) > > > > Probably restarting the host as it got SIGTERM'd by init. Maybe it was > > restarted in a bad time and there is some inconsistency on the disk? > > Using something like libvirt-guests which can manage your machines when > > rebooting would be a good idea. > > > > > 2022-01-20 23:41:17.716+0000: shutting down, reason=crashed > > > 2022-01-20 23:42:46.059+0000: starting up libvirt version: 7.10.0, qemu > > > version: 6.2.0, kernel: 5.10.89-1-MANJARO, hostname: -redacted- > > > > > > Please excuse my ignorance but is there a way to restart the > > > networking without rebooting the host machine? This will not solve my > > > > You can do: > > > > virsh net-destroy <network_name> > > virsh net-start <network_name> > > > > but depending on what the network looks like, how it is set up etc. you > > might need to restart some of the VMs or manually plug them in. > > The connection between any guest tap device and a host bridge device will be > broken by virsh net-destroy, and not restored by virsh net-start (because > the network driver has no good way of notifying the QEMU driver that it has > restarted a network). This is something that's been on my "list of annoying > things I should fix some day" for a very long time, but I've never been > motivated enough to figure out a clean solution. > > In the meantime, if you destroy/start a network, you can get all the guest > tap devices reconnected by restarting libvirtd: > > systemctl restart libvirtd.service > > or if you're using split daemons: > > systemctl restart virtqemud.service > > One of the things the QEMU driver does when it's initializing is to check > where each guest tap device *should* be connected, compare that to where it > *is* connected, and if those don't match then fix it. >
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