- Users - libvirt List Archives

Access to an OCFS2 Partition outside the VM
by Lentes, Bernd 18 Mar '21

18 Mar '21

Hi, i'm thinking about installing two Ubuntu versions on one pc, one as a host system with KVM, the other in a virtual domain. I need access from both to several OCFS2 partitions with big amount of data. The partitions are on harddisks attached to that pc. Is it possible to access an OCFS2 partition which is outside the domain ? And if yes how can i do that ? I know that i have to configure OCFS2 and that i need DLM. Buth systems have network, that shouldn't be the problem. Bernd -- Bernd Lentes System Administrator Institute for Metabolism and Cell Death (MCD) Building 25 - office 122 HelmholtzZentrum München bernd.lentes(a)helmholtz-muenchen.de phone: +49 89 3187 1241 phone: +49 89 3187 3827 fax: +49 89 3187 2294 http://www.helmholtz-muenchen.de/mcd Helmholtz Zentrum MÃ¼nchen Helmholtz Zentrum Muenchen Deutsches Forschungszentrum fuer Gesundheit und Umwelt (GmbH) Ingolstaedter Landstr. 1 85764 Neuherberg www.helmholtz-muenchen.de Aufsichtsratsvorsitzende: MinDir.in Prof. Dr. Veronika von Messling Geschaeftsfuehrung: Prof. Dr. med. Dr. h.c. Matthias Tschoep, Kerstin Guenther Registergericht: Amtsgericht Muenchen HRB 6466 USt-IdNr: DE 129521671

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Updating dnsmasq options with virsh net-update
by Alex Crawford 18 Mar '21

18 Mar '21

I'm trying to take advantage of libvirt's support for passing through options to dnsmasq <https://libvirt.org/formatnetwork.html#elementsNamespaces>, but I'm having trouble getting it to take effect. I have a network already created and I'm trying to use net-update to add the options, but it's not clear to me what section I should specify. By the way, is there a good way to list the available sections? I've been resorting to reading the code <https://gitlab.com/libvirt/libvirt/-/blob/18d0f2f9569edf3c26d912a7d8974a54b…>. Working in a different direction, I tried using net-edit to make the changes but they seem to have been silently discarded: $ virsh -c qemu:///system net-edit crawford-libvirt-67v2h Network crawford-libvirt-67v2h XML configuration edited. $ virsh -c qemu:///system net-dumpxml crawford-libvirt-67v2h | grep --count <my changes> 0 Can anyone tell me what I'm doing wrong or how this feature was intended to be used? Thank you. -Alex

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Question about migrate the vm with host-passthrough cpu
by Guoyi Tu 17 Mar '21

17 Mar '21

Hi there, Sorry to bother you, but could I ask you a question about the live migration of virtual machine configured with host-passthough cpu, it confuse me a lot. Here i have two hosts with different cpu, and the cpu feature set of old host is subset of the new one (by virsh cpu-compare). If the vm was first started on the old host,is it safe to migrate the vm between the two hosts back and forth with the vm always keep running? I've test the case in my environment, and the migration succeeds, the cpu family/model/stepping and features of lscpu in Guest OS is the same. -- Best Regards, Guoyi Tu

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Using cgroups in QEMU hooks
by Melissa Nuño 17 Mar '21

17 Mar '21

Hi all, I'm creating a device during the prepare hook, and would like to add it to the device.allow file for the VM. The cgroup doesn't exist during the prepare hook or the start hook and will fail with an "Operation not permitted" error. I can add the expected path to qemu.conf and restart libvirtd, but this isn't very flexible since I'd have to do it for each device for each VM I create. All of the other libvirt cgroups seem to allow all devices, so I'm not seeing where the VM cgroup is getting its initial list. Is there a way to access the cgroup for a VM before it has started? I can't even predict where it should be since it contains the domain ID. Thanks!

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Re: Issue
by Samuel Thampy 12 Mar '21

12 Mar '21

Is there any additional info anyone who needs? ________________________________ From: Samuel Thampy <samjiks(a)hotmail.com> Sent: 03 March 2021 22:11 To: libvirt-users(a)redhat.com <libvirt-users(a)redhat.com> Subject: Issue I have a storage backend san disks, I have five servers which is KVM hosted guests. I am looking to clone an image of a guest machine, so I can use a new VM form the image on a different server.. I am not sure what the best way. But when I do that, I get a memory error, and need to xfs_repair and damages the original machine. My steps are One vm machine on the same server * dd create original vm to template.img * lvcreate -L 9G -n <vol-name> <pool> * dd template.img to /dev/<pool>/<vol-name> * virsh define <vm_name>.xml another vm machine on the secondary server * copy template.img to another server * lvcreate -L 9G -n <vol-name> <pool> * dd if=template.img of=/dev/<pool>/<vol-name> * virsh define <vm_name>.xml May I know the steps are missing something because both are getting corrupted. Thanks for your help. Regards Samuel Thampy

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Bridge and VLAN trunk
by Gionatan Danti 11 Mar '21

11 Mar '21

Dear list, I am a question about the best use of bridge, vlan trunk and libvirt. When dealing with virtual machies bound to specific vlan, I generally use a straightforward approach: eth -> bridge -> vm (for untagged traffic) eth -> eth.10 -> bridge -> vm eth -> eth.nn -> bridge -> vm Now I am faced with enabling vlan trunking for a specific vm (a virtualized firewall). The simpler approach would be: eth -> bridge -> vm (for the vm needing trunk) eth -> bridge.10 -> macvtap -> vm The issue with the above method is that any VM on the main untagged vlan needs to be bound to the "plain" bridge, having access to *any* traffic of *any* other vlan. If this is ok (and the desired behavior) for the firewall, it is clearly wrong for the other VMs. A simple fix would be to use ebtables to block/drop vlan tagged traffic on the main bridge for any virtual adapter except the required one (ie: the firewall virtual interface). It works, but I wounder if other preferred approaches exists. For example, I tested another more convoluted setup: eth -> bridge -> firewall vm eth -> bridge.10 -> macvtap -> vm eth -> bridge -> veth0 -> veth1 -> other bridge with vlan filtering on -> vm The last row show the use of veth virtual interface, configurable via ip link. Enabling vlan filtering on the second bridge (rather than on the first) is to keep vlan filtering simple: rathen than enabling all required vlan on the first bridge, I simply enable only untagged traffic on the second one. Does libvirt support bridge vlan filtering natively? Reading the docs, it seems to the supported only on OpenVSwitch or SRV-IO based adapter. Thanks. -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti(a)assyoma.it - info(a)assyoma.it GPG public key ID: FF5F32A8

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Snapshot operation aborted and volume usage
by Liran Rotenberg 11 Mar '21

11 Mar '21

We recently had this bug[1]. The thought that came from it is the handling of error code after running virDomainSnapshotCreateXML, we encountered VIR_ERR_OPERATION_ABORTED(78). Apparently, the new volume is in use. Are there cases where this will happen and the new volume won't appear in the volumes chain? Can we detect / know when? Thinking aloud, if we can detect such cases we can prevent rolling back by reporting it back from VDSM to ovirt. Or, if it can't be detected to go on the safe side in order to save data corruption and prevent the rollback as well. Currently, in ovirt, if the job is aborted, we will look into the chain to decide whether to rollback or not. Regards, Liran. [1] - https://bugzilla.redhat.com/show_bug.cgi?id=1916122

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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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