March 2021 - Users - libvirt List Archives

virsh snapshot-create-as with quiesce option times out
by David Wells 05 Mar '21

05 Mar '21

Hi all! I'm still working on the live backup of a couple vm's and what happens most of the times es that when I execute virsh with the snapshot-create-as with the --quiesce option the process finishes with an error that reads > error: Timed out during operation: cannot acquire state change lock I tried turning up the debug level but found nothing that appears to be of interest and I can connect successfully to the qemu guest agent since the following command returns the correct value > sudo /usr/sbin/virsh domfsinfo slackware-current > Mountpoint Name Type Target > ------------------------------------------------------------------- > / vda1 ext4 vda I also tried running the qemu-ga agent on the guest with debugging enabled and when I issue this last command I can see the agent talking to the host but when I issue the quiesce option the guest agent shows nothing at all. Is this by any chance a known bug? Is there something obvious I'm missing? What else can I provide to help debug this issue? Thanks in advance! Best regards, David Wells.

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virtio model type and netfilter masquerade not being applied
by Brad Jennings 04 Mar '21

04 Mar '21

Quick question for anyone in the know, I have a fairly basic setup (at least I think it is?) with an openvswitch, and the br0 port has an IP assigned in the same subnet as the VM to act as a gateway. |------ovs-------| eno2 <-- |--br0 | |--vnet0 - VM | |------------------| I would like the VM (vnet0) to use br0 as a gateway which local connectivity wise seems fine but the internet is a bit odd. I can ping for example 1.1.1.1 dns without any issues but anying udp/tcp is a no go. I checked the physical hosts interface(eno2) and br0 to find that the VM's packets were successfully heading to br0 but when leaving the physical host(eno2) the tcp/udp packets weren't being masqueraded. The rule is pretty straightforward and to test I plugged another device into the eno1 afxdp port and had no connectivity issues and packets were being masqueraded fine. I tried to set trustGuestRxFilters='yes' but that didn't work and the same state remained, the only thing that worked was using the "rtl8139" model type. I always remember using 'virtio' in the past and I must be missing something crucial in the somewhat lengthy libvirt documentation. Would be super helpful if someone can shed some light on this ? and possibly if I should be using virtio or the realtek driver ? Thanks ! (config below) Iptables: sudo iptables -t nat -A POSTROUTING -o eno2 -j MASQUERADE ovs-vsctl show ec13c3e2-6159-4019-984e-36cc90c59075 Bridge br0 fail_mode: standalone datapath_type: netdev Port vnet0 Interface vnet0 Port eno1 Interface eno1 type: afxdp Port br0 Interface br0 type: internal instance domain xml <interface type='bridge'> <mac address='52:54:00:77:fc:70'/> <source bridge='br0'/> <virtualport type='openvswitch'> <parameters interfaceid='2124ef39-e244-434c-8339-d2aa04d0d888'/> </virtualport> <model type='virtio'/> #rtl8139 works. <address type='pci' domain='0x0000' bus='0x02' slot='0x01' function='0x0'/> </interface>

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Some confusion about lsilogic controller
by xingchaochao 03 Mar '21

03 Mar '21

Hello, I have been confused by such a phenomenon recently. Libvirt is the master branch , and the VM is centos8.2(kernel is 4.18.0-193.el8.aarch64). When I hot-plug the scsi disk for a virtual machine without a virtio-scsi controller, libvirt will automatically generate an lsilogic controller for the scsi disk. <disk type='file' device='disk'> <driver name='qemu' type='qcow2' cache='none' io='native'/> <source file='/Images/xcc/tmp.img'/> <backingStore/> <target dev='sdt' bus='scsi'/> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </disk> linux-upcHIq:/Images/xcc # virsh list Id Name State ---------------------- 12 g1 running linux-upcHIq:/Images/xcc # virsh attach-device g1 disk.xml Device attached successfully linux-upcHIq:/Images/xcc # virsh dumpxml g1 | grep scsi <target dev='sdt' bus='scsi'/> <alias name='scsi0-0-0'/> <controller type='scsi' index='0' model='lsilogic'> <alias name='scsi0'/> But this scsi disk cannot be found through the lsblk command inside the virtual machine. [root@localhost ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT vda 252:0 0 20G 0 disk ├─vda1 252:1 0 600M 0 part /boot/efi ├─vda2 252:2 0 1G 0 part /boot └─vda3 252:3 0 18.4G 0 part ├─cl-root 253:0 0 16.4G 0 lvm / └─cl-swap 253:1 0 2G 0 lvm [SWAP] After hot unplugging the scsi disk, I performed the hot unplug operation of the lsilogic controller. libvirt shows "Device detached successfully", but in fact, the lsilogic controller is not removed from the live XML and persistent XML. Through "virsh dumpxml vmname" and "virsh edit vmname", I can see <controller type='scsi' index='0' model='lsilogic'> is always there. linux-upcHIq:/Images/xcc # virsh detach-device g1 disk.xml Device detached successfully linux-upcHIq:/Images/xcc # virsh dumpxml g1 | grep scsi <controller type='scsi' index='0' model='lsilogic'> <alias name='scsi0'/> linux-upcHIq:/Images/xcc # linux-upcHIq:/Images/xcc # cat lsi.xml <controller type='scsi' index='0' model='lsilogic'> <alias name='scsi0'/> <address type='pci' domain='0x0000' bus='0x03' slot='0x05' function='0x0'/> </controller> linux-upcHIq:/Images/xcc # virsh detach-device g1 lsi.xml Device detached successfully linux-upcHIq:/Images/xcc # virsh dumpxml g1 | grep scsi <controller type='scsi' index='0' model='lsilogic'> <alias name='scsi0'/> I am confused, why libvirt chooses to generate an lsilogic controller for the scsi disk when there is no scsi controller, instead of directly reporting an error and exiting the hot plug operation. After all, the scsi disk based on the lsilogic controller is not perceived inside the virtual machine, and lsilogic will remain in the XML file of the virtual machine.

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Live backups create-snapshot-as and memspec
by David Wells 01 Mar '21

01 Mar '21

Hi all! I've been using libvirt for some time and until now I have treated backups of virtual computers as if they where physical computers installing the backup client on the guest. I am now however facing the need to backup a couple a couple of guest at the host level so I've been trying to catch up by reading, googling and by trial and error too. Up to now I've been able to backup a live machine whith a command like the following > virsh snapshot-create-as --domain test --name backup --atomic > --diskspec vda,snapshot=external --disk-only This command creates a file test.backup and in the meantime I can backup the original test.qcow2 but for what I saw this disk image is in a "dirty" state, as if the machine I could restore from this file had been turned off whithout a proper shutdown. I know that I can later restore the machine to its original state by issuing a command like this > virsh blockcommit --domain test vda --active --pivot > virsh snapshot-delete test --metadata backup I have seen that it is possible to create the snapshot using a memspec parameter which would make the backup of the guest as if it where in a clean state, however I haven't found the equivalent of the blockcommit for the memory file, in a sort of speak, to be able to restore the guest to it's original state. Thank you very much! Best regards. David Wells.

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