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Cannot start network interfaces
by Iain M Conochie 28 Jan '25

28 Jan '25

Good day all, I have having an issue starting virtual networks defined within libvirt: virsh # net-start cmdb error: Failed to start network cmdb error: internal error: Child process (VIR_BRIDGE_NAME=virbr3 /usr/sbin/dnsmasq --conf-file=/var/lib/libvirt/dnsmasq/cmdb.conf -- leasefile-ro --dhcp-script=/usr/lib/libvirt/libvirt_leaseshelper) unexpected exit status 2: dnsmasq: failed to create listening socket for 172.26.80.1: Address already in use The definition of the network is pretty simple: virsh # net-dumpxml cmdb <network> <name>cmdb</name> <uuid>42ffd3c4-624d-46ad-be21-bb3c61c67e41</uuid> <bridge name='virbr3' stp='on' delay='0'/> <mac address='52:54:00:5b:e9:6c'/> <domain name='shihad.org'/> <ip address='172.26.80.1' netmask='255.255.255.0'> </ip> </network> At the OS level, this network interface should get created by libvirt, so I am a bit mystified why dnsmasq is having an issue starting, as there is nothing using this address yet. In fact, virbr3 does not exist until libvirt would bring up this interface: ifconfig -a | grep virbr virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 I am running libvirt 9.0.0 on Debian 12. Any help or pointers greatly appreciated. Thanks! Iain

4 7

RBD pool not starting "An error occurred, but the cause is unknown"
by Stuart Longland VK4MSL 28 Jan '25

28 Jan '25

Hi all, I have an issue getting a RBD pool going on a newly deployed compute node. The storage back-end is a Ceph storage cluster running Ceph 14 (Nautilus… yes I know this is old, an update to 18 is planned soon). I have an existing node, running Debian 10 (again, updating this is planned, but I'd like to deploy new nodes to migrate the instances to whilst this node is updated), which runs about a dozen VMs with disks on this back-end. I've loaded a new machine (a MSI Cubi 5 mini PC) up with AlpineLinux 3.21. Boot disk is a 240GB SATA SSD, and there's a 1TB nVME for local VM storage. My intent is to allow VMs to mount RBDs for back-up purposes. The machine has two Ethernet interfaces (a 2.5Gbps and a 1Gbps link), one will be the "front-end" used by the VMs, the other will be a "back-end" link to talk to Ceph and administer the host. - OpenVSwitch 2.17.11 is deployed with two bridges - libvirtd 10.9.0 installed - a LVM pool called 'data' has been created on nVME - Ceph 19.2.0 is installed (libvirtd is linked to this version of librbd) - /etc/ceph has been cloned from my existing working compute node I have two RBD pools; 'one' and 'ha'. 'one' has most of my virtual machine images in it (it is from a former OpenNebula install), 'ha' has core router root disk images in it ('ha' for high availability; it has stronger replication settings than 'one' to guarantee better reliability). I've created a `libvirt` user in Ceph, and on the intended node, this works: > ~ # rbd --id libvirt ls -p one | head > mastodon-vda > mastodon-vdb > mastodon-vdd > mastodon-vde > one-14 > one-15 > one-19 > one-20 > one-22 > one-23 > ~ # rbd --id libvirt ls -p ha | head > core-router-obsd75-vda > core-router-obsd76-vda I can also access RBD images just fine: > ~ # rbd --id libvirt map one/shares-vda > /dev/rbd0 > ~ # fdisk -l /dev/rbd0 > Disk /dev/rbd0: 20 GB, 21474836480 bytes, 41943040 sectors > 2610 cylinders, 255 heads, 63 sectors/track > Units: sectors of 1 * 512 = 512 bytes > > Device Boot StartCHS EndCHS StartLBA EndLBA Sectors Size Id Type > /dev/rbd0p1 * 2,0,33 611,8,56 2048 616447 614400 300M 83 Linux > /dev/rbd0p2 611,8,57 1023,15,63 616448 2584575 1968128 961M 82 Linux swap > /dev/rbd0p3 1023,15,63 1023,15,63 2584576 41943039 39358464 18.7G 83 Linux > ~ # rbd unmap one/shares-vda This is registered in libvirtd: > ~ # virsh secret-list > UUID Usage > -------------------------------------------------------------------- > c14a16b5-bba5-473a-ae9b-53a9a6b0a4e3 ceph client.libvirt secret > ~ # virsh secret-dumpxml c14a16b5-bba5-473a-ae9b-53a9a6b0a4e3 > <secret ephemeral='no' private='no'> > <uuid>c14a16b5-bba5-473a-ae9b-53a9a6b0a4e3</uuid> > <usage type='ceph'> > <name>client.libvirt secret</name> > </usage> > </secret> I have defined four pools, 'temp', 'local', 'ha-images' and 'opennebula-images': > ~ # virsh pool-list --all > Name State Autostart > ------------------------------------------- > default active yes > ha-images active yes > local active yes > opennebula-images inactive yes > temp active yes 'ha-images' works just fine, this is its config: > ~ # virsh pool-dumpxml ha-images > <pool type='rbd'> > <name>ha-images</name> > <uuid>6beab982-52b3-495b-a4a7-ab7ebb522ef5</uuid> > <capacity unit='bytes'>20003977953280</capacity> > <allocation unit='bytes'>159339114496</allocation> > <available unit='bytes'>13142248669184</available> > <source> > <host name='172.31.252.1' port='6789'/> > <host name='172.31.252.2' port='6789'/> > <host name='172.31.252.5' port='6789'/> > <host name='172.31.252.6' port='6789'/> > <host name='172.31.252.7' port='6789'/> > <host name='172.31.252.8' port='6789'/> > <host name='172.31.252.9' port='6789'/> > <host name='172.31.252.10' port='6789'/> > <name>ha</name> > <auth type='ceph' username='libvirt'> > <secret uuid='c14a16b5-bba5-473a-ae9b-53a9a6b0a4e3'/> > </auth> > </source> > </pool> 'opennebula-images' does not, its config: > ~ # virsh pool-dumpxml opennebula-images > <pool type='rbd'> > <name>opennebula-images</name> > <uuid>fcaa2fa8-f0d2-4919-9168-756a9f4ad7ee</uuid> > <capacity unit='bytes'>20003977953280</capacity> > <allocation unit='bytes'>5454371495936</allocation> > <available unit='bytes'>13142254759936</available> > <source> > <host name='172.31.252.1' port='6789'/> > <host name='172.31.252.2' port='6789'/> > <host name='172.31.252.5' port='6789'/> > <host name='172.31.252.6' port='6789'/> > <host name='172.31.252.7' port='6789'/> > <host name='172.31.252.8' port='6789'/> > <host name='172.31.252.9' port='6789'/> > <host name='172.31.252.10' port='6789'/> > <name>one</name> > <auth type='ceph' username='libvirt'> > <secret uuid='c14a16b5-bba5-473a-ae9b-53a9a6b0a4e3'/> > </auth> > </source> > </pool> It's not obvious what the differences are. `name`, `uuid`, `allocation`, `available` and `source/name` are expected to be different, everything else 100% matches. I've tried removing and zeroing out the `capacity`, `allocation` and `available` tags to no effect. > ~ # virsh pool-dumpxml ha-images > /tmp/ha-images.xml > ~ # virsh pool-dumpxml opennebula-images > /tmp/opennebula-images.xml > ~ # diff -u /tmp/ha-images.xml /tmp/opennebula-images.xml > --- /tmp/ha-images.xml > +++ /tmp/opennebula-images.xml > @@ -1,9 +1,9 @@ > <pool type='rbd'> > - <name>ha-images</name> > - <uuid>6beab982-52b3-495b-a4a7-ab7ebb522ef5</uuid> > + <name>opennebula-images</name> > + <uuid>fcaa2fa8-f0d2-4919-9168-756a9f4ad7ee</uuid> > <capacity unit='bytes'>20003977953280</capacity> > - <allocation unit='bytes'>159339114496</allocation> > - <available unit='bytes'>13142248669184</available> > + <allocation unit='bytes'>5454371495936</allocation> > + <available unit='bytes'>13142254759936</available> > <source> > <host name='172.31.252.1' port='6789'/> > <host name='172.31.252.2' port='6789'/> > @@ -13,7 +13,7 @@ > <host name='172.31.252.8' port='6789'/> > <host name='172.31.252.9' port='6789'/> > <host name='172.31.252.10' port='6789'/> > - <name>ha</name> > + <name>one</name> > <auth type='ceph' username='libvirt'> > <secret uuid='c14a16b5-bba5-473a-ae9b-53a9a6b0a4e3'/> > </auth> > ~ # diff -y /tmp/ha-images.xml /tmp/opennebula-images.xml When I start this errant pool, I get this: > ~ # virsh pool-start opennebula-images > error: Failed to start pool opennebula-images > error: An error occurred, but the cause is unknown If I crank debugging up in `libvirtd` (via the not-recommended `log_level` and directing all output to a file), I see it successfully connects to the pool for about 15 seconds, lists the sizes of about a dozen disk images, then seemingly gives up and disconnects. > 2025-01-19 05:16:55.176+0000: 3609: info : vir_object_finalize:319 : OBJECT_DISPOSE: obj=0x7f975fc816a0 > 2025-01-19 05:16:55.177+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975fc816a0 > 2025-01-19 05:16:55.183+0000: 3609: debug : virStorageBackendRBDRefreshPool:693 : Utilization of RBD pool one: (kb: 19535134720 kb_ > avail: 12800438616 num_bytes: 5489355030528) > 2025-01-19 05:16:55.988+0000: 3609: debug : volStorageBackendRBDRefreshVolInfo:569 : Refreshed RBD image one/mastodon-vda (capacity > : 21474836480 allocation: 21474836480 obj_size: 4194304 num_objs: 5120) > 2025-01-19 05:16:55.993+0000: 3609: info : virObjectNew:256 : OBJECT_NEW: obj=0x7f975fa6bba0 classname=virStorageVolObj > 2025-01-19 05:16:55.993+0000: 3609: info : virObjectRef:400 : OBJECT_REF: obj=0x7f975fa6bba0 > 2025-01-19 05:16:55.993+0000: 3609: info : virObjectRef:400 : OBJECT_REF: obj=0x7f975fa6bba0 > 2025-01-19 05:16:55.993+0000: 3609: info : virObjectRef:400 : OBJECT_REF: obj=0x7f975fa6bba0 > 2025-01-19 05:16:55.993+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975fa6bba0 > 2025-01-19 05:16:56.011+0000: 3609: debug : volStorageBackendRBDRefreshVolInfo:569 : Refreshed RBD image one/mastodon-vdb (capacity > : 536870912000 allocation: 536870912000 obj_size: 4194304 num_objs: 128000) …snip… > 2025-01-19 05:17:03.756+0000: 3609: debug : volStorageBackendRBDRefreshVolInfo:569 : Refreshed RBD image one/wsmail-vdb (capacity: > 21474836480 allocation: 21474836480 obj_size: 4194304 num_objs: 5120) > 2025-01-19 05:17:03.758+0000: 3609: info : virObjectNew:256 : OBJECT_NEW: obj=0x7f975f9cf250 classname=virStorageVolObj > 2025-01-19 05:17:03.758+0000: 3609: info : virObjectRef:400 : OBJECT_REF: obj=0x7f975f9cf250 > 2025-01-19 05:17:03.758+0000: 3609: info : virObjectRef:400 : OBJECT_REF: obj=0x7f975f9cf250 > 2025-01-19 05:17:03.758+0000: 3609: info : virObjectRef:400 : OBJECT_REF: obj=0x7f975f9cf250 > 2025-01-19 05:17:03.758+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975f9cf250 > 2025-01-19 05:17:03.777+0000: 3609: debug : volStorageBackendRBDRefreshVolInfo:569 : Refreshed RBD image one/sjl-router-obsd76-vda > (capacity: 34359738368 allocation: 34359738368 obj_size: 4194304 num_objs: 8192) > 2025-01-19 05:17:03.778+0000: 3609: debug : virStorageBackendRBDCloseRADOSConn:369 : Closing RADOS IoCTX > 2025-01-19 05:17:03.778+0000: 3609: debug : virStorageBackendRBDCloseRADOSConn:374 : Closing RADOS connection > 2025-01-19 05:17:03.783+0000: 3609: debug : virStorageBackendRBDCloseRADOSConn:378 : RADOS connection existed for 15 seconds > 2025-01-19 05:17:03.783+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975f9cf2b0 > 2025-01-19 05:17:03.783+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975ef90ac0 > 2025-01-19 05:17:03.783+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975fa6bd20 > 2025-01-19 05:17:03.783+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975fa6ecc0 …snip… > 2025-01-19 05:17:03.785+0000: 3609: info : vir_object_finalize:319 : OBJECT_DISPOSE: obj=0x7f975f9cee90 > 2025-01-19 05:17:03.785+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975f9cee90 > 2025-01-19 05:17:03.785+0000: 3609: info : vir_object_finalize:319 : OBJECT_DISPOSE: obj=0x7f975fa6e960 > 2025-01-19 05:17:03.785+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975fa6e960 > 2025-01-19 05:17:03.785+0000: 3609: error : storageDriverAutostartCallback:213 : internal error: Failed to autostart storage pool 'opennebula-images': no error > 2025-01-19 05:17:03.785+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975fcd0490 > 2025-01-19 05:17:03.785+0000: 3609: info : virObjectRef:400 : OBJECT_REF: obj=0x7f975fcd27c0 > 2025-01-19 05:17:03.785+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975fcd27c0 > 2025-01-19 05:17:03.786+0000: 3609: info : virObjectRef:400 : OBJECT_REF: obj=0x7f975fcd06d0 > 2025-01-19 05:17:03.786+0000: 3609: info : virObjectUnref:378 : OBJECT_UNREF: obj=0x7f975fcd06d0 > 2025-01-19 05:17:03.786+0000: 3609: info : virObjectRef:400 : OBJECT_REF: obj=0x7f975fcd0130 If there's no cause for the error, it should not fail. If it fails, there should be a cause listed, there's no excuse for it being "unknown" -- just because Microsoft's OSes make up error codes that its own help system can't explain is no excuse for the open-source world to follow their example. I'd happily provide more information, if someone can provide guidance on how to locate it. -- Stuart Longland (aka Redhatter, VK4MSL) I haven't lost my mind... ...it's backed up on a tape somewhere.

2 2

Authoritative info on backup-begin versus snapshots/other state capture
by camccuk＠yahoo.com 17 Jan '25

17 Jan '25

Hello all Apologies for the basic nature of the question, but having recently started working with libvirt - and virtualisation in general - I find there is a lot of out-of-date and sometimes contradictory material out there across blogs, articles, stackoverflow, the usual sources... I thought I might be able to get definitive answers here. For the record, I assume libvirt.org is authoritative but while there is a lot of material there, its structure is not always clear to me. Also the lack of dates on any pages leaves some room for doubt. I am wondering if there is a recent, reliable summary of the various approaches and current best practices for backing up VMs that covers snapshots both internal and external, approaches that use backup-begin and third-party approaches which simply stop the VM and copy off files. If there is not such a summary, can anyone confirm my reading of https://libvirt.org/kbase/domainstatecapture.html that a simple backup-begin <domain-name> will: - pause the VM and quiesce the disk (in which case is qemu agent a requirement on the guest?) - generate a date-suffixed disk-only copy of a VMs disks alongside the originals wherever that storage is - not generate any backing image chains or metadata that needs to be retained Furthermore, is it then possible to restore to that point by stopping a VM, and associating that backup file with the VM either by virsh-editing its xml or overwriting the original file with the backup file. This seems to be my experience in testing this, but there are very few references to this tool compared to the many lengthy discussions about snapshots and other approaches which is a bit puzzling. It would be great to have this understanding confirmed or refined! Many thanks for any pointers

2 4

libvirt-guests on Redhat
by Joe Muller 06 Jan '25

06 Jan '25

Hello, Per libvirt and Redhat (up to RHEL7) documentation, the libvirt-guests daemon should be enabled to ensure that guest VMs are properly shutdown/suspended if the KVM host is shutdown/rebooted. I understand that in addition to other changes, Redhat moved from the 'monolithic' libvirtd service model to the 'modular' multiple service model. Out of the box, the systemd libvirt-guests.service is disabled, and testing shows that the associated qemu-kvm processes for virtual machines are simply killed as the various virt* services are stopped as part of the systemd shutdown target. Did Redhat just decide to fork libvirt and do their own thing, or there some equivalent way to get the same clean shutdown behavior which libvirt-guests used to provide? Relevant documentation: --- https://libvirt.org/daemons.html https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/9/html/co… -- Joe Muller System Administrator Sonic.

2 1

Best practice to manage network
by linux＠hklb.ch 03 Jan '25

03 Jan '25

Hi, First, sorry if the topic has already been discussed recently (the only thread I found related to my problem was created in 2010..) I have a hypervisor with KVM and LXC installed on a Debian 12, and I'm using libvirt to create my VM. All my networks are defined in my /etc/network/interfaces.d/* (I'm using openvswitch with specific options, such as port mirroring/patch/...) , and I'm configuring the network on my VM XML definition like this : <interface type='bridge'> <mac address='52:54:00:ab:c3:d3'/> <source bridge='prod'/> <vlan> <tag id='55'/> </vlan> <virtualport type='openvswitch'> <parameters interfaceid='331d973c-0c5b-4d3c-b2ad-590f908e680d'/> </virtualport> <target dev='vnet180'/> <model type='virtio'/> <mtu size='9216'/> <alias name='net1'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </interface> It is working perfectly, until I'm restarting my network (using ifreload, ifup, systemctl network restart, ...) - all my VM come unreachable... To make it work again, I also need to restart libvirtd Is it still expected to have this behavior ? What would be a better way to configure the network ? Thanks in advance Lucas

2 1

kernel panic when hotswapping nvidia gpu via gpu passthrough in a windows vm
by 5zj1zxgr＠anonaddy.me 30 Dec '24

30 Dec '24

This may be more issue with nvidia drivers, but just wanted to check if anyone tried to perform gpu passthrough with an nvidia gpu that is used as a secondary gpu on a nvidia "prime" laptop - laptop with both an integrated intel iGPU and a secondary nvidia dGPU. I was able SOMETIMES to perform GPU passthrough successfully with a VM, but SOMETIMES it led to kernel panics. It usually happens when virtual machine shuts down and nvidia dGPU is returned to the host. Dec 30 14:29:53 host kernel: ACPI Error: Needed [Integer/String/Buffer], found [Reference] 00000000f0ed5a9d (20240827/exresop-388) Dec 30 14:29:53 host kernel: ACPI Error: AE_AML_OPERAND_TYPE, While resolving operands for [And] (20240827/dswexec-433) Dec 30 14:29:53 host kernel: ACPI Error: Aborting method \_SB.PCI0.LPCB.EC0._Q20 due to previous error (AE_AML_OPERAND_TYPE) (20240827/psparse-529) Dec 30 14:29:56 host kernel: ACPI Error: Needed [Integer/String/Buffer], found [Reference] 0000000059be91f0 (20240827/exresop-388) Dec 30 14:29:56 host kernel: ACPI Error: AE_AML_OPERAND_TYPE, While resolving operands for [And] (20240827/dswexec-433) Dec 30 14:29:56 host kernel: ACPI Error: Aborting method \_SB.PCI0.LPCB.EC0._Q20 due to previous error (AE_AML_OPERAND_TYPE) (20240827/psparse-529) Any advice would be really appreciated.

1 0

Re: Features from Capabilities
by Simon Fairweather 23 Dec '24

23 Dec '24

For HyperV looks like I can build a list from the schema, but for CPU options would I use the xml in /usr/share/libvirt/cpu

1 0

Features from Capabilities
by Simon Fairweather 22 Dec '24

22 Dec '24

HI, Is there any documentation or somewhere I can look at features that could be selected? I have started to create an extract from capabilities and domcapabilities to provide a list I can use for selection. Example these are the following entries I have selected to allow running of Hyperv in Server 2019 <features> <acpi/> <apic/> <hyperv mode='custom'> <relaxed state='on'/> <vapic state='on'/> <spinlocks state='on' retries='8191'/> <vendor_id state='on' value='none'/> </hyperv> </features> <cpu mode='custom' match='strict' check='none'> <model fallback='forbid'>Skylake-Client-IBRS</model> <topology sockets='1' dies='1' clusters='1' cores='4' threads='1'/> </cpu> <clock offset='localtime'> <timer name='hpet' present='no'/> <timer name='hypervclock' present='no'/> </clock> But looking to find a list of options that would be valid to be specified. Regards Simon.

1 0

Overriding qemu.conf libvirt-qemu user per-domain
by Pascal Proulx 20 Dec '24

20 Dec '24

Hello, How can I override the libvirt-qemu user defined in /etc/libvirt/qemu.conf using a per-domain (virtual machine) override using the domain XML definitions? I can find qemu arg overrides but not this and I may have missed it. Thank you

2 2

List of valid arch's for virt-install
by Jeffrey Walton 13 Dec '24

13 Dec '24

Hi Everyone, I'm converting about 150 Virtual Box vm's to QEMU/KVM using `qemu-img convert` followed by a `virt-install`. The vm's are a mix of amd64, i686 and mx32, and they will run on a amd64 machine. I want to use the `virt-install --arch` option during the conversion. The man page for virt-install [1] does not list valid arch's. (I can't find a page for virt-install at libvirt.org) Where can I find the list of valid arch's for virt-install? A related question is, if I also specify `--cpu host` to ensure the host cpu's ISA's are available to the vm, then will that conflict with the `--arch arch` option? Thanks in advance. [1] https://manpages.org/virt-install

3 4

Running libvirt without dnsmasq
by procmem＠riseup.net 10 Dec '24

10 Dec '24

Hi, we are trying to document a way for our users to run libvirt without dnsmasq to reduce attack surface on the host. We are aware that the default network uses it but plan to disable that and use our own custom configured networks instead. Uninstalling dnsmasq causes libvirt to refuse to start even if the default network is no longer running. Is this possible or is this something that needs code changes upstream?

5 8

linux guests can ping websites but cannot browse the internet while Windows guest has no issues, using 'default' nat forwarding
by persev＠guysmail.com 06 Dec '24

06 Dec '24

Hello. I had been using linux and Windows guests with QEMU KVM for a long time with no issues on LinuxMint 21.2. Then one day all the linux guests could not connect to the internet effectively. (I guess, an apt upgrade has some responsibility here, not sure). Then I installed LinuxMint 22, hoping to get an overall upgrade. Setup a Debian 12 KVM guest anew but noticed the same issues. I can ping websites from inside the VM and there are no packet loss. But other than that, the VM seemingly cannot connect to the internet. `ping wikipedia.org` works flawless but `curl` results in the following: $ curl -v 'wikipedia.org' Trying 103.102.166.224:80... Trying [<IPv6 address>]:80... Immediate connect failed for [<IPv6 address>]:80... Network is unreachable doing an apt update also results in Network unreachable. Also, Firefox cannot load websites. So it appears the guest vm can only resolve dns names and nothing else. Surprisingly, I have a Windows guest that has no internet issue at all; websites load fine in Edge. My Android Virtual Device (which uses qemu) works fine too. What might be the problem here? Am I missing some configuration in the host? Any help is appreciated. What other info can I post here to help identify the problem? $ uname -a Linux hp 6.8.0-49-generic #49-Ubuntu SMP PREEMPT_DYNAMIC Mon Nov 4 02:06:24 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux $ virsh net-dumpxml default <network connections='1'> <name>default</name> <uuid>...</uuid> <forward mode='nat'> <nat> <port start='1024' end='65535'/> </nat> </forward> <bridge name='virbr0' stp='on' delay='0'/> <mac address='52:54:00:44:e6:c0'/> <ip address='192.168.122.1' netmask='255.255.255.0'> <dhcp> <range start='192.168.122.2' end='192.168.122.254'/> </dhcp> </ip> </network> The network tag from xml config for this debian12 VM is <interface type="network"> <mac address="52:54:00:79:b8:39"/> <source network="default" portid="c2529d6f-088f-4b5d-8829-625d494213e5" bridge="virbr0"/> <target dev="vnet0"/> <model type="virtio"/> <alias name="net0"/> <address type="pci" domain="0x0000" bus="0x02" slot="0x00" function="0x0"/> </interface> From inside the guest $ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host noprefixroute valid_lft forever preferred_lft forever 2: enp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 52:54:00:79:b8:39 brd ff:ff:ff:ff:ff:ff inet 192.168.122.65/24 brd 192.168.122.255 scope global dynamic noprefixroute enp2s0 valid_lft 2549sec preferred_lft 2549sec inet6 fe80::b96d:f09b:80d1:b1ae/64 scope link noprefixroute valid_lft forever preferred_lft forever

2 1

Re: Set permissions and ownership of disk image created by vol-upload
by Martin Kletzander 26 Nov '24

26 Nov '24

On Tue, Nov 19, 2024 at 07:01:39PM +0000, Andrew Martin wrote: >Hello, > >I am using libvirt 8.0 on Ubuntu 22.04 and would like to utilize the vol-upload >command to upload a disk image: >https://www.libvirt.org/manpages/virsh.html#vol-upload > >I am using the "directory" storage pool type: >https://libvirt.org/storage.html#directory-pool > >However, when uploading the disk image, it gets written with octal permissions >0600 and owner root:root. Ideally I'd like this file to be owned by >libvirt-qemu:libvirt-qemu with permissions 0660 so that the group can read it. > >I've tried the following, none of which seem to alter the owner or permissions: > >- change the umask in the libvirtd systemd unit >- edit the user, group, and dynamic_ownership settings in /etc/libvirt/qemu.conf >- run "virsh pool-edit default" and change the <mode>, <owner>, or <group> tags > >How can I configure libvirtd to create these uploaded files with the desired >permissions and ownership? > Use virsh vol-create <pool> <volume.xml> where the volume xml looks something like this (adjust to your liking): <volume> <name>perms.img</name> <capacity unit='M'>100</capacity> <target> <path>/var/lib/libvirt/images/perms.img</path> <format type='raw'/> <permissions> <mode>0755</mode> <owner>77</owner> <group>77</group> </permissions> </target> </volume> And then use virsh vol-upload to populate the volume with what you want. That ought to be enough. HTH, Martin >Thanks, > >Andrew

2 1

Help building .rpm of libvirt from fork
by Filippo Ferrando Damillano 25 Nov '24

25 Nov '24

Hi, i'm a CS Student who is trying to build a full rpm of libvirt out of a fork <https://gitlab.com/filippo-ferrando/libvirt-sd> because i need to add a scheduler to the libvirt configuration. I successfully builded the source code but i cannot manage to build a working .rpm executable, i'm using a Alma9 machine, and the original .spec file from the build of the repo. When i try to use rpmbuild, it goes until meson.build says that a file called `meson.build` is missing in the directory, even if the file itself exists. my fork is based on the master branch at tag 10.9.0 i'll include in the mail the log from meson and the spec file i'm using, thank to everyone for the help! -- ------------------------ Indirizzo istituzionale di posta elettronica degli studenti e dei laureati dell'Università di TorinoOfficial University of Turin email address for students and graduates

2 1

ZFS storage backend
by Paul B. Henson 22 Nov '24

22 Nov '24

I'm running libvirt to manage virtual machines utilizing ZFS zvol's for storage. For organization and management purposes, these zvol's are nested: virt/qemu/debian12-template 15.8G 1.57T 24K none virt/qemu/debian12-template/bootefi 1.02G 1.57T 141M - virt/qemu/debian12-template/home 522M 1.57T 2.57M - virt/qemu/debian12-template/opt 522M 1.57T 3.00M - virt/qemu/debian12-template/root 8.13G 1.58T 970M - virt/qemu/debian12-template/swap 522M 1.57T 366M - virt/qemu/debian12-template/tmp 522M 1.57T 2.39M - virt/qemu/debian12-template/var 3.05G 1.57T 161M - virt/qemu/debian12-template/varlog 1.02G 1.57T 101M - virt/qemu/debian12-template/vartmp 522M 1.57T 3.75M - The libvirt ZFS integration seems to assume that all zvol's will exist at the top level of the pool, it won't let you create or manage a hierarchical structure. That is what it is, but it also then misrepresents the actual structure and shows things as being in the root when they are not: virsh # vol-list virt Name Path ------------------------------------- backup /dev/zvol/virt/backup boot-nb /dev/zvol/virt/boot-nb bootefi /dev/zvol/virt/bootefi dest /dev/zvol/virt/dest disk1 /dev/zvol/virt/disk1 home /dev/zvol/virt/home opt /dev/zvol/virt/opt root /dev/zvol/virt/root swap /dev/zvol/virt/swap tmp /dev/zvol/virt/tmp usr /dev/zvol/virt/usr usrlocal /dev/zvol/virt/usrlocal usrobj /dev/zvol/virt/usrobj usrports /dev/zvol/virt/usrports usrsrc /dev/zvol/virt/usrsrc var /dev/zvol/virt/var varlog /dev/zvol/virt/varlog vartmp /dev/zvol/virt/vartmp Ideally libvirt would support nested ZFS organizational structure, as that is a very common layout. But even if not, it probably shouldn't misrepresent a structure it doesn't understand? Thanks for any thoughts…

1 0

network usually failing (nested virt, Debian)
by Misha Ramendik 21 Nov '24

21 Nov '24

Hello, I have a VPS where hardware nested virtualization is enabled, and I am trying to use this nested virtualization. The VPS runs Debian 12 and has 16 Gb of RAM. I installed libvirt/virt-manager/etc and downloaded the "nocloud" and "genericcloud" images from https://cdimage.debian.org/images/cloud/ . The description says that the "nocloud" image should allow passwordless root login but unfortunately it does not. I run things as root (this is a test setup) but I did chown all qcow images to "libvirt-qemu". I use the following command line: # virt-install --name test-cloud-vnc --os-variant debian11 --ram 8192 --disk debian-12-genericcloud-amd64.qcow2,device=disk,bus=virtio,size=10,format=qcow2 --hvm --import --noautoconsole --network default --graphics vnc,port=-1,listen=0.0.0.0 (Or the same for the nocloud image) The nocloud image sometimes, rarely, gets a DHCP lease (visible in "virsh net-dhcp-leases-default") and then responds to pings. But usually the nocloud image, and always the cloud image (but this might just be by random numbers), don't get a DHCP lease and cannot be pinged. This means that my attempt to set up cloud-init by an ad hoc webserver (as per https://cloudinit.readthedocs.io/en/latest/tutorial/qemu.html ) never got tested, because the cloud-init image can't access the network to start with. I did try --network default,model=e1000 - no change. I do successfully see the guest console when I connect to the VPS by VNC. Unfortunately, I don't have a password to log in with, so I can't even try to see whether it sees any network adapter. dmesg output for the time: [71382.495314] audit: type=1400 audit(1732157273.151:173): apparmor="STATUS" operation="profile_load" profile="unconfined" name="libvirt-3ca46e41-5cca-40b0-a5cd-d7d7e60de326" pid=30675 c omm="apparmor_parser" [71382.855419] audit: type=1400 audit(1732157273.511:174): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="libvirt-3ca46e41-5cca-40b0-a5cd-d7d7e60de326" pid=3067 8 comm="apparmor_parser" [71383.228796] audit: type=1400 audit(1732157273.883:175): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="libvirt-3ca46e41-5cca-40b0-a5cd-d7d7e60de326" pid=3068 2 comm="apparmor_parser" [71383.626483] audit: type=1400 audit(1732157274.279:176): apparmor="STATUS" operation="profile_replace" info="same as current profile, skipping" profile="unconfined" name="libvirt-3ca46 e41-5cca-40b0-a5cd-d7d7e60de326" pid=30686 comm="apparmor_parser" [71383.664542] virbr0: port 1(vnet0) entered blocking state [71383.667108] virbr0: port 1(vnet0) entered disabled state [71383.671212] device vnet0 entered promiscuous mode [71383.674775] virbr0: port 1(vnet0) entered blocking state [71383.677431] virbr0: port 1(vnet0) entered listening state [71384.077738] audit: type=1400 audit(1732157274.731:177): apparmor="STATUS" operation="profile_replace" profile="unconfined" name="libvirt-3ca46e41-5cca-40b0-a5cd-d7d7e60de326" pid=3069 7 comm="apparmor_parser" [71385.702614] virbr0: port 1(vnet0) entered learning state [71387.718555] virbr0: port 1(vnet0) entered forwarding state [71387.720995] virbr0: topology change detected, propagating I tried to boot the GRML ISO ( https://grml.org/ ) using the following command: # virt-install --name test-cloud-vnc --os-variant debian11 --ram 8192 --disk debian-12-genericcloud-amd64.qcow2,device=disk,bus=virtio,size=10,format=qcow2 --hvm --import --noautoconsole --network default --cdrom grml64-full_2024.02.iso --boot cdrom --graphics vnc,port=-1,listen=0.0.0.0 Unfortunately, the GRML boot hangs shortly after starting, apparently while trying to load the initrd. So I can't poke around in the guest in this way, either. Advice about debugging this would be highly appreciated. -- Yours, Misha Ramendik Unless explicitly stated, all opinions in my mail are my own and do not reflect the views of any organization

1 0

Set permissions and ownership of disk image created by vol-upload
by Andrew Martin 19 Nov '24

19 Nov '24

Hello, I am using libvirt 8.0 on Ubuntu 22.04 and would like to utilize the vol-upload command to upload a disk image: https://www.libvirt.org/manpages/virsh.html#vol-upload I am using the "directory" storage pool type: https://libvirt.org/storage.html#directory-pool However, when uploading the disk image, it gets written with octal permissions 0600 and owner root:root. Ideally I'd like this file to be owned by libvirt-qemu:libvirt-qemu with permissions 0660 so that the group can read it. I've tried the following, none of which seem to alter the owner or permissions: - change the umask in the libvirtd systemd unit - edit the user, group, and dynamic_ownership settings in /etc/libvirt/qemu.conf - run "virsh pool-edit default" and change the <mode>, <owner>, or <group> tags How can I configure libvirtd to create these uploaded files with the desired permissions and ownership? Thanks, Andrew

1 0

Immediate "system reset" when booting UEFI?
by Lars Kellogg-Stedman 18 Nov '24

18 Nov '24

Hey folks, I'm running libvirt 10.1.0/qemu-system-x86-core-9.0.1-1.fc40.x86_64 on Fedora 40. I'm trying to boot an Ubuntu image in UEFI mode, like this: virt-install -r 2048 -n ubuntu.virt --os-variant ubuntu24.04 \ --disk pool=default,size=10,backing_store=mantic-server-cloudimg-amd64.img,backing_format=qcow2 \ --cloud-init root-ssh-key=$HOME/.ssh/id_ed25519.pub \ --boot uefi This results in the domain booting up and then immediately resetting: BdsDxe: loading Boot0001 "UEFI Misc Device" from PciRoot(0x0)/Pci(0x2,0x3)/Pci(0x0,0x0) BdsDxe: starting Boot0001 "UEFI Misc Device" from PciRoot(0x0)/Pci(0x2,0x3)/Pci(0x0,0x0) Reset System Domain creation completed. At this point, the machine is actually powered down and needs to be restarted manually: virsh start ubuntu.virt This works fine, and the domain boots successfully, but now the cloud-init metadata provided by the `--cloud-init` option to `virt-install` is no longer available (because this is no longer the initial, virt-install managed boot of the domain). What is causing the firmware to reset the system when it first boots? -- Lars Kellogg-Stedman <lars(a)redhat.com>

3 3

hard-disk via virtio-blk under windows (discard_granularity=0)
by d tbsky 18 Nov '24

18 Nov '24

Hi: few years ago virtio-blk device was showing as hard-disk under windows. recent years the driver change the device to show as thin-provisioned disk. the change is good for ssd, but not so good for raw hard-disk. under windows server 2022 the default virtio-blk situation is quite bad, ssd trim is very slow. and defrag a bigger volume like 1TB harddisk will always show "memory not enough", even when the volume is empty. I found discussions to change the "discard_granularity" to make trim happy again. and libvirt support the syntax like below: <blockio discard_granularity='2097152'/> I also found if I can set "discard_granularity" to zero, then windows will recognize the device as "traditional hard drive" again and won't do unnecessary trim to it. I want to do this for years, but couldn't find a way to set it up like vitio-scsi's rotational parameter. the sad part is if I setup it under RHEL 9.4 with librirt 10.0 like below: <blockio discard_granularity='0'/> the line will just disappear when I close "virsh edit" so I can only use complex format with "<qemu:override>" to set "discard_granularity='0'" I wonder if libvirt would be changed to accept "discard_granularity='0'" so the traditional hard-disk can be recognized under windows again. or is there better ways to distinguish hard-disk/ssd/thin-disk for virtio-blk now? Regards, tbskyd

3 6

[FOSDEM] Reminder about call for participation - Virtualization and Cloud infrastructure Room 2025
by Piotr Kliczewski 17 Nov '24

17 Nov '24

All, This yeah submission deadline is enforced for all devrooms so this year our due date is on 1st of December not as all previous years on 8th. This is our gentle reminder to submit [0] your proposals. See you soon at FOSDEM! [0] https://fosdem.org/submit

1 0

error: unsupported flags (0x4) in function virStorageVolDefParseXML
by Veiko Kukk 08 Nov '24

08 Nov '24

Hi! Simple volume definition: <volume type='file'> <name>tstlog01-system</name> <capacity unit='GiB'>20</capacity> <target> <compat>1.1</compat> <format type='qcow2'/> </target> </volume> # virsh vol-create --pool libvirt-ssd0 --file vm-files/tstlog01/tstlog01-sys tem-vol.xml --validate error: Failed to create vol from vm-files/tstlog01/tstlog01-system-vol.xml error: unsupported flags (0x4) in function virStorageVolDefParseXML Omitting --validate creates volume # virsh vol-dumpxml --pool libvirt-ssd0 --vol tstlog01-system <volume type='file'> <name>tstlog01-system</name> <key>/var/lib/libvirt/images/tstlog01-system</key> <capacity unit='bytes'>21474836480</capacity> <allocation unit='bytes'>200704</allocation> <physical unit='bytes'>196928</physical> <target> <path>/var/lib/libvirt/images/tstlog01-system</path> <format type='qcow2'/> <permissions> <mode>0600</mode> <owner>0</owner> <group>0</group> <label>system_u:object_r:virt_image_t:s0</label> </permissions> <timestamps> <atime>1730277533.331347844</atime> <mtime>1730277533.329347839</mtime> <ctime>1730277533.330347841</ctime> <btime>0</btime> </timestamps> </target> </volume> # file /var/lib/libvirt/images/tstlog01-system /var/lib/libvirt/images/tstlog01-system: QEMU QCOW2 Image (v2), 21474836480 bytes # virsh vol-create-as libvirt-ssd0 tstlog01-system 20g --format qcow2 Vol tstlog01-system created # virsh vol-dumpxml --pool libvirt-ssd0 --vol tstlog01-system <volume type='file'> <name>tstlog01-system</name> <key>/var/lib/libvirt/images/tstlog01-system</key> <capacity unit='bytes'>21474836480</capacity> <allocation unit='bytes'>200704</allocation> <physical unit='bytes'>196928</physical> <target> <path>/var/lib/libvirt/images/tstlog01-system</path> <format type='qcow2'/> <permissions> <mode>0600</mode> <owner>0</owner> <group>0</group> <label>system_u:object_r:virt_image_t:s0</label> </permissions> <timestamps> <atime>1730277391.657950326</atime> <mtime>1730277391.656950323</mtime> <ctime>1730277391.657950326</ctime> <btime>0</btime> </timestamps> </target> </volume> It seems both volumes are identical - the one created without --validate and the one created with vol-create-as. Questions: 1) Why does validation fail? How to debug it? 2) Why doesn't libvirt create qcow2 v3 even when specifying compat 1.1? When creating an image using virt-manager on the same libvirt hypervisor host, v3 images are created. Alma Linux 9.4, libvirt-10.0.0-6.7.el9_4.alma.1.x86_64, qemu-kvm-8.2.0-11.el9_4.6.x86_64 With best regards, Veiko

2 1

How to assign vHBA to guest VM?
by voron_g＠inbox.ru 02 Nov '24

02 Nov '24

Hi all! I've created several vHBA and i need to assign this device to guest VM Is it possible? Thanks a lot for your answer BR, Gennady

1 0

trustGuestRxFilters broken after upgrade to Debian 12
by Paul B. Henson 01 Nov '24

01 Nov '24

We've been running Debian 11 for a while, using sr-iov: <network> <name>sr-iov-intel-10G-1</name> <uuid>6bdaa4c8-e720-4ea0-9a50-91cb7f2c83b1</uuid> <forward mode='hostdev' managed='yes'> <pf dev='eth2'/> </forward> </network> and allocating vf's from the pool: <interface type='network' trustGuestRxFilters='yes'> <mac address='52:54:00:08:da:5b'/> <source network='sr-iov-intel-10G-1'/> <vlan> <tag id='50'/> </vlan> <model type='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> After upgrading to Debian 12, when I try to start any vm which uses the trustGuestRxFilters option, it fails to start with the message: error: internal error: unable to execute QEMU command 'query-rx-filter': invalid net client name: hostdev0 If I remove the option, it starts fine (but of course is broken functionality wise as the option wasn't there just for fun :) ). Any thoughts on what's going on here? The Debian 12 versions are: libvirt-daemon/stable,now 9.0.0-4 qemu-system-x86/stable,now 1:7.2+dfsg-7+deb12u3 I see Debian 12 backports has version 8.1.2+ds-1~bpo12+1 of qemu, but no newer versions of libvirt. I haven't tried the backports version to see if that resolves the problem. Thanks much...

5 7

reconfiguring a two vms bridge to two vms + the host with proper iface naming
by daggs 29 Oct '24

29 Oct '24

Greetings, I have two vms (vm1 and vm2) connected via a bridge named br1. libvirt creates two taps, tap0 and tap1 I'm trying to rename them to some thing more meaningful for starts. I assume that I cannot use vnet-vm1 or vnet-vm2 so I decided to configure it like this: vm1: <interface type='bridge'> <source bridge='br1'/> <target dev='vnet1'/> </interface> vm2: <interface type='bridge'> <source bridge='br1'/> <target dev='vnet2'/> </interface> but when start the vms, the iface names are still tap1 and tap2. am I doing something wrong? in addition, I want to add the host to br1, so I ran this after the bridge exists: ip link set dev tap3 master br1 I see it when I run brctl show br1, but I'm unable to get ip, am I doing something wrong here too? Thanks, Dagg.

3 4

[FOSDEM] Call for participation: Virtualization and Cloud infrastructure Room at FOSDEM 2025
by Piotr Kliczewski 28 Oct '24

28 Oct '24

We are excited to announce that the call for proposals is now open for the Virtualization and Cloud infrastructure devroom at the upcoming FOSDEM 2025, to be hosted on Sunday (Feb 2) 2025. This devroom is a collaborative effort, and is organized by dedicated folks from projects such as OpenStack, Xen Project, KubeVirt, QEMU, KVM, and Foreman. We invite everyone involved in these fields to submit your proposals by December 8th, 2024. About the Devroom The Virtualization & IaaS devroom will feature session topics such as open source hypervisors or virtual machine managers such as Xen Project, KVM, bhyve and VirtualBox as well as Infrastructure-as-a-Service projects such as KubeVirt, Apache CloudStack, OpenStack, QEMU and OpenNebula. This devroom will host presentations that focus on topics of shared interest, such as KVM; libvirt; shared storage; virtualized networking; cloud security; clustering and high availability; interfacing with multiple hypervisors; hyperconverged deployments; and scaling across hundreds or thousands of servers. Presentations in this devroom will be aimed at developers working on these platforms who are looking to collaborate and improve shared infrastructure or solve common problems. We seek topics that encourage dialog between projects and continued work post-FOSDEM. Important Dates Submission deadline: 8th December 2024 Acceptance notifications: 10th December 2024 Final schedule announcement: 15th December 2024 Devroom: 2nd February 2025 Submit Your Proposal All submissions must be made via the Pretalx event planning site[1]. It is a new submission system so you will need to create an account. If you submitted proposals for FOSDEM in previous years, you won’t be able to use your existing account. During submission please make sure to select Virtualization and Cloud infrastructure from the Track list. Please provide a meaningful abstract and description of your proposed session. Submission Guidelines We expect more proposals than we can possibly accept, so it is vitally important that you submit your proposal on or before the deadline. Late submissions are unlikely to be considered. All presentation slots are 30 minutes, with 20 minutes planned for presentations, and 10 minutes for Q&A. All presentations will be recorded and made available under Creative Commons licenses. In the Submission notes field, please indicate that you agree that your presentation will be licensed under the CC-By-SA-4.0 or CC-By-4.0 license and that you agree to have your presentation recorded. For example: "If my presentation is accepted for FOSDEM, I hereby agree to license all recordings, slides, and other associated materials under the Creative Commons Attribution Share-Alike 4.0 International License. Sincerely, <NAME>." In the Submission notes field, please also confirm that if your talk is accepted, you will be able to attend FOSDEM and deliver your presentation. We will not consider proposals from prospective speakers who are unsure whether they will be able to secure funds for travel and lodging to attend FOSDEM. (Sadly, we are not able to offer travel funding for prospective speakers.) Code of Conduct Following the release of the updated code of conduct for FOSDEM[3], we'd like to remind all speakers and attendees that all of the presentations and discussions in our devroom are held under the guidelines set in the CoC and we expect attendees, speakers, and volunteers to follow the CoC at all times. If you submit a proposal and it is accepted, you will be required to confirm that you accept the FOSDEM CoC. If you have any questions about the CoC or wish to have one of the devroom organizers review your presentation slides or any other content for CoC compliance, please email us and we will do our best to assist you. Questions? If you have any questions about this devroom, please send your questions to our devroom mailing list. You can also subscribe to the list to receive updates about important dates, session announcements, and to connect with other attendees. See you all at FOSDEM! [1] https://pretalx.fosdem.org/fosdem-2025/cfp [2] virtualization-devroom-manager at fosdem.org [3] https://fosdem.org/2025/practical/conduct/

1 0