- Users - libvirt List Archives

Libvirtd slower over time
by André Malm 29 Aug '22

29 Aug '22

Hello, I have some issues with libvirtd getting slow over time. After a fresh reboot (or systemctl restart libvirtd) virsh list / virt-install is fast, as expected, but after a couple of months uptime they both take a significantly longer time. Virsh list takes around 3 seconds (from 0.04s on a fresh reboot) and virt-install takes over a minute (from around a second). Running strace on virsh list it seems to get stuck in a loop on this: poll([{fd=5<socket:[173169773]>, events=POLLOUT}, {fd=6<anon_inode:[eventfd]>, events=POLLIN}], 2, -1) = 2 ([{fd=5, revents=POLLOUT}, {fd=6, revents=POLLIN}]) While restarting libvirtd fixes it a restart takes around 1 minute where ebtables rules etc are recreated and it does interrupt the service. What could cause this? How would I troubleshoot this? I'm running Ubuntu 22.04 / libvirt 8.0.0 with 70 active VM’s on a 16/32 core machine with 256GB of ram, CPU is below 50% usage at all times, memory below 50% usage and swap 0% usage. Thanks, André

1 0

Libvirt web application
by Callie Martin 25 Aug '22

25 Aug '22

Hello, We received the following message on Red Hat's Twitter account. Can anyone on this list confirm if libvirt-users(a)redhat.com is 1) active and 2) the right contact information for this user to reach out to? [image: image.png] Thanks, -- Callie Martin She / Her / Hers Manager, Social Media Red Hat <https://www.redhat.com/> 100 E. Davie St. Raleigh, NC calmarti(a)redhat.com M: 919-630-7721 | T: 919-890-8011 @RedHat <https://twitter.com/redhat> Red Hat <https://www.linkedin.com/company/red-hat> Red Hat <https://www.facebook.com/RedHatInc> <https://red.ht/sig>

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NUMA node - Memory Only
by Jin Huang 22 Aug '22

22 Aug '22

Hi, libvirt-users How could I set up a memory-only and no-cpu NUMA node for the qemu-VM with the XML file? Seems each NUMA cell has to be bundled with some specific cpuids. If I write the element like this, it is wrong. <cpu mode='host-passthrough'> <numa> <cell id='0' cpus='0-3' memory='16' unit='GiB'/> <cell id='1' cpus='*null*' memory='16' unit='GiB'/> </numa> </cpu> Also if I ignore the cpus item, it is not acceptable for the virsh command. The reason I want the memory-only node is that I want to set up multiple memory tiers for the VM, just like https://stevescargall.com/2022/06/10/using-linux-kernel-memory-tiering/ Thank You Best Jin Huang

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Memory locking limit and zero-copy migrations
by Milan Zamazal 19 Aug '22

19 Aug '22

Hi, do I read libvirt sources right that when <memtune> is not used in the libvirt domain then libvirt takes proper care about setting memory locking limits when zero-copy is requested for a migration? I also wonder whether there are any other situations where memory limits could be set by libvirt or QEMU automatically rather than having no memory limits? We had oVirt bugs in the past where certain VMs with VFIO devices couldn't be started due to extra requirements on the amount of locked memory and adding <hard_limit> to the domain apparently helped. Thanks, Milan

4 10

Problem with a disk device of type 'volume'
by Frédéric Lespez 18 Aug '22

18 Aug '22

Hi, I need some help to debug a problem with libvirt and a disk device of type 'volume'. I have a VM failing to start with the following error : $ virsh -c qemu:///system start server error :Failed to start domain 'server' error :internal error: process exited while connecting to monitor: 2022-08-13T09:26:50.121259Z qemu-system-x86_64: -blockdev {"driver":"file","filename":"/mnt/images/debian-11-genericcloud-amd64.qcow2","node-name":"libvirt-3-storage","auto-read-only":true,"discard":"unmap"}: Could not open '/mnt/images/debian-11-genericcloud-amd64.qcow2': Permission denied I check the file access permission, but they are correct. I try to set everything to 777 or run qemu as root, but the problem persist. $ ll -d /mnt /mnt/images /mnt/images/* drwxr-xr-x 9 root root 4,0K 31 déc. 2021 /mnt drwxr-xr-x 2 root root 4,0K 13 août 11:31 /mnt/images -rw-r--r-- 1 libvirt-qemu libvirt-qemu 242M 13 août 11:31 /mnt/images/debian-11-genericcloud-amd64.qcow2 -rw-r--r-- 1 libvirt-qemu libvirt-qemu 366K 13 août 11:31 /mnt/images/server_cloudinit.iso -rw-r--r-- 1 libvirt-qemu libvirt-qemu 593M 13 août 11:59 /mnt/images/server_image.qcow2 After a lot of searching and testing, I found out that the disk device definition is linked to the source of the problem. The disk device is defined like this : <disk type="volume" device="disk"> <driver name="qemu" type="qcow2"/> <source pool="TERRAFORM" volume="server_image.qcow2"/> <target dev="vda" bus="virtio"/> <address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x0"/> </disk> This image 'server_image.qcow2' use a backing file: $ qemu-img info /mnt/images/server_image.qcow2 --backing-chain image: /mnt/stockage_rapide/VMs/terraform/puppetdev_server_image.qcow2 file format: qcow2 virtual size: 6 GiB (6442450944 bytes) disk size: 475 MiB cluster_size: 65536 backing file: /mnt/images/debian-11-genericcloud-amd64.qcow2 backing file format: qcow2 Format specific information: compat: 0.10 compression type: zlib refcount bits: 16 image: /mnt/images/debian-11-genericcloud-amd64.qcow2 file format: qcow2 virtual size: 2 GiB (2147483648 bytes) disk size: 242 MiB cluster_size: 65536 Format specific information: compat: 1.1 compression type: zlib lazy refcounts: false refcount bits: 16 corrupt: false extended l2: false And here is the definition of the associated storage pool : <pool type="dir"> <name>TERRAFORM</name> <uuid>dae00836-db4d-49ba-9d32-1f0278055516</uuid> <capacity unit="bytes">155674652672</capacity> <allocation unit="bytes">74396299264</allocation> <available unit="bytes">81278353408</available> <source> </source> <target> <path>/mnt/images</path> <permissions> <mode>0755</mode> <owner>0</owner> <group>0</group> </permissions> </target> </pool> If I changed the disk device definition to this (and changing only that), the domain start and works fine (no permission problem !). <disk type="file" device="disk"> <driver name="qemu" type="qcow2"/> <source file="/mnt/images/server_image.qcow2"/> <target dev="vda" bus="virtio"/> <address type="pci" domain="0x0000" bus="0x00" slot="0x05" function="0x0"/> </disk> Could you help me find the reason why the domain doesn't work when the disk device is of type 'volume' ? Thanks in advance for your help. Regards, Fred Additional information: - Running this on Debian 11 with libvirt 8.0.0 (from backports) and qemu 7.0 (from backports). - Vanilla configuration of libvirt. I have just added my regular user to the libvirt group. - Problem exists even if AppArmor is disabled. PS: I want to use a disk device of type 'volume' because this domain is created by Terraform using the libvirt provider which use this kind of disk since it has some advantages. See the details here : https://github.com/dmacvicar/terraform-provider-libvirt/issues/126#issuecom…

2 3

Libvirt virsh : Error starting network, cannot execute binary /usr/sbin/iptables
by Pascal 17 Aug '22

17 Aug '22

Hi, I am a bit lost and hope someone can help me. I am running Debian bookworm (testing) with last updates. $ sudo apt policy libvirt-daemon libvirt-daemon: Installé : 8.5.0-1 Candidat : 8.5.0-1 Table de version : *** 8.5.0-1 100 100 /var/lib/dpkg/status I am unable to start default network , and get an error related to iptables : $ sudo virsh net-start default erreur :Impossible de démarrer le réseau default erreur :internal error: Failed to apply firewall rules /usr/sbin/iptables -w --table filter --list-rules: libvirt: erreur : cannot execute binary /usr/sbin/iptables: Aucun fichier ou dossier de ce type Sorry for the french, it says "impossible to start default network" and "no such file or folder" at the end. It is true I removed iptables because I want to use only nftables (I removed both ufw and iptables packages (apt remove), and enabled the nftables service before error raises). Before this, all was fine, but when I enabled nftables, all VMs disapeared from virt-manager). I uninstalled KVM related packages and reinstalled, still the same. I also installed back iptables, but strangely I still get the same error, although binary /usr/sbin/iptables is there. I tried many things with no luck, restarted libvirtd service, recreated the network, etc... Has anyone some idea about what is happening here ? is there some incompatibility with nftables (firewalld service is disabled) and libvirt ? Thank you, Pascal

2 2

libvirt can't setup simple bridged network?
by Ian Pilcher 15 Aug '22

15 Aug '22

I feel like I'm taking crazy pills! I'm reading the libvirt network XML format documentation[1], and I can't figure out how to create a simple bridged network - no NAT, no routing, no OVS, no macvtap, etc. I.e., just a Linux bridge with a single physical interface attached. None of the 3 scenarios listed for <forward mode='bridge'> describe the simple setup that I'm trying to create, so it looks like I'll need to create the bridge separately. (It's not hard to do, it just seems like such a weird gap the in the functionality.) [1] https://libvirt.org/formatnetwork.html -- ======================================================================== Google Where SkyNet meets Idiocracy ========================================================================

4 3

New functionality in virt-install
by O'Reilly, Michael 09 Aug '22

09 Aug '22

Hi libvirt-users, I've been tracking the progress of this patch https://listman.redhat.com/archives/libvir-list/2022-August/233328.html to enable SGX support in libvirt. My question is this. Who is responsible for ensuring that new functionality like SGX is also supported by virt-install? Is it part of the commit process to ensure virt-install can use the new functionality in libvirt, or is it up to the virt-manager community to track changes. And maybe this is a question for the virt-tools-list(a)redhat.com list also? Some guidance would be appreciated. Regards Michael OR -------------------------------------------------------------- Intel Research and Development Ireland Limited Registered in Ireland Registered Office: Collinstown Industrial Park, Leixlip, County Kildare Registered Number: 308263 This e-mail and any attachments may contain confidential material for the sole use of the intended recipient(s). Any review or distribution by others is strictly prohibited. If you are not the intended recipient, please contact the sender and delete all copies.

2 1

Can RHEL7 VM run remote commands to Fedora36 host?
by Carol Bouchard 01 Aug '22

01 Aug '22

I have a Fedora36 laptop which hosts VMs with RHEL7 using libvirt. One of the RHEL7 VMs, runs remote commands (as root) to 'start' another VM by way of my laptop. In other words, the following command is run: virsh --connect 'qemu+ssh://192.168.120.1/system' start beaker-test-vm1.beaker If I run non-remote version of the command on the laptop, it is successful. For example, virsh --connect qemu:///system start beaker-test-vm1.beaker <-- Successful on laptop. If I do a query like the following *(notice socket use)*, it is successful. virsh -d0 --connect 'qemu+ssh://192.168.120.1/system?*socket*=/var/run/libvirt/libvirt-sock-ro' domstate beaker-test-vm1.beaker Without socket, I get the following error: *error: failed to connect to the hypervisor* *error: End of file while reading data: Ncat: No such file or directory.: Input/output error* This does not work for 'start' because I believe this is a read-only socket since I see the error: error: Failed to start domain beaker-test-vm1.beaker error: operation forbidden: read only access prevents virDomainCreate When I look at my laptop, there is no /var/run/libvirt/libvirt-sock. So.....I've been wondering whether RHEL7 virsh/libvirt is compatible with Fedora36. Is there a work-around? I can't change the distros on my laptop or VMs. Carol

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Can RHEL7 VM run remote libvirt commands to Fedora36 host?
by Carol Bouchard 01 Aug '22

01 Aug '22

I have a test environment that use to work but no longer does. My laptop is Fedora36 (libvirt version 8.1.0.2) while the VMs it spawns are RHEL7 (max libvirt version is 4.5.0). The source of my problem seems to be that RHEL7 libvirt needs rw socket /var/run/libvirt/libvirt-sock which no longer exists in fedora36. The following is successful from RHEL7 VM to laptop: virsh -d0 --connect 'qemu+ssh://192.168.120.1/system?*socket*=/var/run/libvirt/libvirt-sock-ro' domstate beaker-test-vm1.beaker If I change the action from domstate to start, it fails on error: Failed to start domain beaker-test-vm1.beaker error: operation forbidden: read only access prevents virDomainCreate which made me realize ro stands for read-only; however, there is no libvirt-sock. I tried some of the other socket files without success. Is there a work-around? Carol

2 3

how to get vm uptime through libvirt api
by Jiatong Shen 26 Jul '22

26 Jul '22

Hello community, I would like to know if there is an api to get a virtual machine's uptime. Thank you in advance for the help. -- Best Regards, Jiatong Shen

3 8

Eject CD ROM medium fails with 'Tray of device is not open'
by liang chaojun 25 Jul '22

25 Jul '22

Hi Guys, I have hit an issue on testing against our testbed, It's failed to eject cdrom media after reboot from installed the guest OS. The reproduce step: 1. Attach a block device with a ISO media and start install VM from ISO. 2. <disk type='block' device='cdrom'> <driver name='qemu' type='raw'/> <source dev='/dev/disk/by-id/pbdx-vol-cfe60dca-c271-491b-be3c-11fa8d7625a4' index='6'/> <backingStore/> <target dev='hda' bus='ide' tray='open'/> <readonly/> <alias name='ide0-0-0'/> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </disk> 3. After installed the OS and reboot from system disk successful. 4. Then I want to eject CDROM through update device with the xml like below or using virsh tool 'virsh change-media iso_test hda --eject' 5. All those will failed at "internal error: unable to execute QEMU command 'blockdev-remove-medium': Tray of device 'ide0-0-0' is not open" <disk type='block' device='cdrom'> <driver name='qemu' type='raw'/> <backingStore/> <target dev='hda' bus='ide' tray='open'/> <readonly/> <alias name='ide0-0-0'/> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </disk> block info looks like below: virsh qemu-monitor-command iso_test --hmp info block setlocale: No such file or directory libvirt-6-format: /dev/disk/by-id/pbdx-vol-cfe60dca-c271-491b-be3c-11fa8d7625a4 (raw, read-only) Attached to: ide0-0-0 Removable device: locked, tray closed Cache mode: writeback Reproduce envrionment: Operating system: rhat8.4 Architecture:x86 kernel version:4.18.0-305 libvirt version:v7.9.0(private build) Hypervisor and version:QEMU 5.1.0(private build) Is there any workaround? Any comments are appreciated. Thanks!

2 3

NetworkD or NetworkManager. Does it matter?
by Mnecraftchest1 24 Jul '22

24 Jul '22

Hello there. I am in the process of building an Arch Linux install for a virtualization server for my home lab, and I am trying to decide what networking system I should use. The two I am considering are SystemD-NetworkD, and NetworkManager. Looking along the lines of support from libvirt, would I be better off with one or the other, or does it not matter which one I use?

1 0

The default USB controller of pc machine type
by Han Han 15 Jul '22

15 Jul '22

Hello, I found that the default USB controller for q35 machine type is qemu-xhci while for pc it is piix3-uhci. Here are the results(on qemu-kvm-7.0.0 qemu-kvm-7.0.0): ➜ ~ cat /tmp/usb.xml <domain type="kvm"> <name>USB</name> <uuid>1a81d4ef-6537-4ae8-b257-8a15e0c0525f</uuid> <memory>2097152</memory> <currentMemory>2097152</currentMemory> <vcpu>1</vcpu> <os> <type arch="x86_64" machine="q35">hvm</type> <boot dev="hd"/> </os> <devices> <emulator>/usr/libexec/qemu-kvm</emulator> </devices> </domain> ➜ ~ virsh define /tmp/usb.xml && virsh dumpxml USB|grep usb Domain 'USB' defined from /tmp/usb.xml <controller type='usb' index='0' model='qemu-xhci'> ➜ ~ cat /tmp/usb-pc.xml <domain type="kvm"> <name>USB</name> <uuid>1a81d4ef-6537-4ae8-b257-8a15e0c0525f</uuid> <memory>2097152</memory> <currentMemory>2097152</currentMemory> <vcpu>1</vcpu> <os> <type arch="x86_64" machine="pc">hvm</type> <boot dev="hd"/> </os> <devices> <emulator>/usr/libexec/qemu-kvm</emulator> </devices> </domain> ➜ ~ virsh define /tmp/usb-pc.xml && virsh dumpxml USB|grep usb Domain 'USB' defined from /tmp/usb-pc.xml <controller type='usb' index='0' model='piix3-uhci'> And the default usb controller for q35 has been added since: ed2049ea19 qemu: auto-add generic xhci rather than NEC xhci to Q35 domains As I know, pc machine supports qemu-xhci as well. Morever, the performance of qemu-xhci is better than piix3-uhci. So why not update the default usb controller of pc machine type to qemu-xhci? I think we can improve it here.

2 3

Why can not get the expected cpu topology after setting the maxcpu in xml?
by liang chaojun 15 Jul '22

15 Jul '22

Hello all, I hit a issue that I'm not able to see the expected cpu topology in VM after setting the maxcpu arrtribute in domain. the xml look like below: <vcpu placement='static' current='4'>8</vcpu> <cpu mode='host-passthrough' check='none' migratable='on'> <topology sockets='2' dies='1' cores='4' threads='1'/> </cpu> I notice that the cpu topoloy looked like below capture output from 'lscpu' tool which is totally different with my setting. CPU(s): 4 On-line CPU(s) list: 0-3 Thread(s) per core: 1 Core(s) per socket: 4 Socket(s): 1 NUMA node(s): 1 Vendor ID: GenuineIntel CPU family: 6 Model: 63 Model name: Intel(R) Xeon(R) CPU E5-2699 v3 @ 2.30GHz Besides i found it looked correct if i relpace 'vcpu' line with "<vcpu placement='static'>8</vcpu>" that remove maxcpu value. Could you give me some information? Any comments are appreciated. Thanks

1 0

systemtap stapvirt tool
by Stan Cox 07 Jul '22

07 Jul '22

I am having a quandary with libvirt and am wondering if someone can shed some light. Systemtap converts a probing and instrumentation language into a kernel module. The module can optionally be run remotely via ssh or libvirt. The libvirt mechanism is not working (not yet sure of timing of regression) The systemtap stap command pipes to a stapvirt command that is the libvirt interface. The remote is running a stapsh tool that receives the requests. The initial commands are sent and received okay (strace output on remote) but never receives the stap kernel module: # local sent option data request [pid 11959] read(3, "option data\n", 4096) = 12 # remote says OK [pid 11959] write(3, "OK\n", 3) = 3 [pid 11959] poll([{fd=3, events=POLLIN}, {fd=0, events=0}, {fd=0, events=0}], 3, -1) = 1 ([{fd=3, revents=POLLIN}]) [pid 11959] --- SIGIO {si_signo=SIGIO, si_code=SI_KERNEL} --- [pid 11959] poll([{fd=3, events=POLLHUP}], 1, 0) = 0 (Timeout) [pid 11959] rt_sigreturn({mask=[]}) = 1 # local sent file ... request to download the module [pid 11959] read(3, "file 926928 stap_1f18b4b54e74602"..., 4096) = 58 # remote opens the module [pid 11959] openat(AT_FDCWD, "stap_1f18b4b54e74602a0a1f0685f2f7333e_1006.ko", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 4 # but never receives it [pid 11959] read(3, "", 4096) = 0 The local sets up callbacks for stdin, stdout, stream: ctxt.stdin_w = virEventAddHandle(STDIN_FILENO, VIR_EVENT_HANDLE_READABLE, stdin_event, &ctxt, NULL); ... ctxt.stdout_w = virEventAddHandle(STDOUT_FILENO, 0, stdout_event, &ctxt, NULL); ... virStreamEventAddCallback(ctxt.st, VIR_STREAM_EVENT_READABLE | VIR_EVENT_HANDLE_WRITABLE, stream_event, &ctxt, NULL) < 0) Then starts an even loop while (!disconnect) { if (virEventRunDefaultImpl() != 0) break; } stream_event is notified for the command requests, but is not notified for the kernel module chunks: stdin_event excerpt: bytes_read = read(fd, ctxt->termbuf + ctxt->termbuf_off, sizeof(ctxt->termbuf) - ctxt->termbuf_off); ... ctxt->termbuf_off += bytes_read; ... if (ctxt->termbuf_off) { // we have stuff to write to the stream virStreamEventUpdateCallback(ctxt->st, VIR_STREAM_EVENT_READABLE | VIR_STREAM_EVENT_WRITABLE); } stream_event excerpt: if ((events & VIR_STREAM_EVENT_READABLE) && (ctxt->stbuf_off < sizeof(ctxt->stbuf))) { int bytes_recv = virStreamRecv(st, ctxt->stbuf + ctxt->stbuf_off, sizeof(ctxt->stbuf) - ctxt->stbuf_off); I notice https://libvirt.org/html/libvirt-libvirt-stream.html has an example using virStreamSend. Is that the preferred way to do the above?

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Incomplete information in the website Wiki for libvirt.org
by Uriel Emmanuel Pelaez Hernández 04 Jul '22

04 Jul '22

Dear Web Marster from wiki.libvirt.org, I tried to look for the libvirtd, the demon that is suppose to run under Linux/Unix environment, but your site didn't show any information. Only a statement appeared: "Create the page libvirtd " Please, update your site or suggest any other weblink with the information. In theory CygWin use your package, but the information is incomplete too, about this issue. I send this mail to these both Email address by the information displayed in your wiki, about the contact address to solve this kind of problems. By now, Google Service in my region is deprecated, so the information that the WebBrowser display is not the best. I send this request from my Email of Graduated Student form the University domain. Best Regards, Mr. Peláez Uriel. Mexico City

2 1

Storage Pool - NFS v4.1
by Charles Koprowski 01 Jul '22

01 Jul '22

Hello, In order to use pNFS which is only available in NFS version 4.1, I'm trying to create a netfs storage pool specifying the protocol version to be used : <pool type="netfs"> <name>vms</name> <source> ... <format type="nfs"/> <protocol ver='4.1'/> </source> <target> ... </pool> But the storage pool XML documentation [1] states that : protocol For a netfs Storage Pool provide a mechanism to define which NFS protocol version number will be used to contact the server's NFS service. The attribute ver accepts an unsigned *integer* as the version number to use. And indeed, when I try to virsh pool-define I get : error: Failed to define pool from pool.xml error: XML error: storage pool protocol ver '4.1' is malformed How can I specify the desired NFS minor version to libvirt ? I could mount the NFS share myself and build a dir storage pool on top of it but that's not very pretty. Thank you, [1] https://libvirt.org/formatstorage.html -- Charles

2 3

libvirt and Ledger Nano or hotswappable single USB port with virt-manager - almost there?
by Anonymous Aardvark 28 Jun '22

28 Jun '22

Hi I am holding off on a full VFIO system (with a host just used for hosting and main hardware forwarded) until after a build a new PC for the coming generation of graphics cards but I have started using virt-manager to partition my workspaces. My host is Ubuntu 20.04 running QEMU v 5.0 on and Intel i5-4690K CPU and GA-Z97X-Gaming 5 motherboard. Guest is Debian 11. I am trying to solve the issue of how the Ledger Nano X changes its product ID when using different applications <https://imil.net/blog/posts/2020/ledger_on_kvm/>. Unfortunately all ports seem to be in the same IOMMU group so I cannot just forward a controller. I have learned that although my temporary fallback Virtualbox allows forwarding by vendor ID without a product ID <https://www.reddit.com/r/ledgerwallet/comments/mf872x/how_can_you_run_ledge…>, and I have seen some libvirt references to this, including mention of a patch that apparently should have been implemented I have not been able to make it work: from QEMU to libvirt(virsh) - add USB-port <https://stackoverflow.com/questions/46421962/from-qemu-to-libvirtvirsh-add-…> Can I pass through a USB Port via qemu Command Line? <https://unix.stackexchange.com/questions/452934/can-i-pass-through-a-usb-po…> Detail on on my comprehensive hotplugger attempts to forward a single port here <https://www.reddit.com/r/VFIO/comments/lbvgpr/comment/idzml1k/?utm_source=s…> . Can you please tell me if there is some way I can edit either my debian.xml or how hotplugger interacts with the socket so that I can forward a single port that is hotswapable and/or so that Ledger Nano X will stay visible on the guest even after it changes product ID? Thanks Aard.

1 0

Domain XML and VLAN tagging
by Gionatan Danti 19 Jun '22

19 Jun '22

Hi all, from here [1]: "Network connections that support guest-transparent VLAN tagging include 1) type='bridge' interfaces connected to an Open vSwitch bridge Since 0.10.0 , 2) SRIOV Virtual Functions (VF) used via type='hostdev' (direct device assignment) Since 0.10.0 , and 3) SRIOV VFs used via type='direct' with mode='passthrough' (macvtap "passthru" mode) Since 1.3.5 . All other connection types, including standard linux bridges and libvirt's own virtual networks, do not support it." I read it correctly that when used on a classical linux bridge these vlan tags does nothing? If so, it is due to something related to the underlying bridge device (ie: incomplete support for vlan filtering) or it is because libvirt lacks the necessary "plumbing" to use advanced bridge features? Thanks. [1] https://libvirt.org/formatdomain.html#setting-vlan-tag-on-supported-network… -- 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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managed save returns "migration with virtiofs device is not supported"
by Francesc Guasch 16 Jun '22

16 Jun '22

Hello. I have a virtual machine with a virtiofs entry configured. When I try to do a managed save it fails with this message: libvirt error code: 55, message: Requested operation is not valid: migration with virtiofs device is not supported This is libvirt 8.0.0 that comes with Ubuntu 22.04. I have seen the current release in git is libvirt 8.5 . I will try to build from source and try again if you think this was not the expected behaviour. This is the filesystem entry: <filesystem type='mount' accessmode='passthrough'> <driver type='virtiofs'/> <source dir='/home/shared'/> <target dir='home_shared'/> <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/> </filesystem> Sorry if this is not the right place to ask. I can write an issue in gitlab or whatever is more appropriate. Thanks !

4 3

managed save returns "migration with virtiofs device is not supported"
by Francesc Guasch 15 Jun '22

15 Jun '22

Hello. I have a virtual machine with a virtiofs entry configured. When I try to do a managed save it fails with this message: libvirt error code: 55, message: Requested operation is not valid: migration with virtiofs device is not supported This is libvirt 8.0.0 that comes with Ubuntu 22.04. I have seen the current release in git is libvirt 8.5 . I will try to build from source and try again if you think this was not the expected behaviour. This is the filesystem entry: <filesystem type='mount' accessmode='passthrough'> <driver type='virtiofs'/> <source dir='/home/shared'/> <target dir='home_shared'/> <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/> </filesystem> Sorry if this is not the right place to ask. I can write an issue in gitlab or whatever is more appropriate. Thanks !

1 0

After restarted libvirtd service, live migration VM hit an issue 'Target CPU check default does not match source none'
by 梁朝军 15 Jun '22

15 Jun '22

Hi All, After restarted the libvirtd service on the source host, we start live migration VM to destination host and often hit an issue 'unsupported configuration: Target CPU check default does not match source none’ We don’t configure any special setting for CPU model when start VM and I think it should be ‘custom’ mode by default . Furthermore , those two hosts for doing live migration have almost the same capabilities as below. It’s confused me why failed to check the cpu configuration after restart libvitd service on source host? The libvirt version is 7.9.0, package: 1.el8 (Unknown, 2021-11-28-22:35:11) private build Host OS version : rhat8.4 QEMU version: QEMU 5.1 private build Any comments are appreciated. Thanks

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Domain XML of a restored VM
by Tomáš Golembiovský 14 Jun '22

14 Jun '22

Hi, I am looking for clarification on what exactly is happening to the domain XML when resuming a suspended VM. We would like to make sure we don't lose any configuration and we also see some unexpected behavior. The VM with the name/UUID same as resumed VM may or may not already exist. If it does, what role does the original domain XML of a VM play when resuming? Is there any merging taking place between the existing domain XML and the domain XML stored in save image? Is the original XML simply thrown away and replaced? Is there any difference how the stored XML is treated compared to the XML passed in `virDomainRestoreFlags()`? I see some unexpected changes here. When I use `virDomainSaveImageGetXMLDesc()` to retrieve the stored XML and pass it unchanged to the `virDomainRestoreFlags()` the final domain XML is different then when `virDomainRestore()` is used or when `virDomainRestoreFlags()` with no `dxml` argument is used. We have: <graphics ... passwdValidTo='1970-01-01T00:00:01'> in the domain XML and the `passwdValidTo` argument disappears when domain XML is passed in `dxml` argument but it is preserved in other cases. Is this behavior expected? If yes, can we do anything to preserve the configuration? What other changes in domain XML can be expected? Thanks, Tomas -- Tomáš Golembiovský <tgolembi(a)redhat.com>

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vepa-mode directly attached interface
by Gionatan Danti 13 Jun '22

13 Jun '22

Hi all, I just realized that libvirt default for directly attached interface is vepa mode. I discovered it now because virt-manager automatically enables bridge mode, while cockpit-machines get the default vepa mode. This is unfortunate because, being vepa switches very rare, it means that using cockpit to configure directly attached interfaces causes guests to not talk each other. I have some questions: - can libvirt default be changed/configured somehow (ie: to automatically create bridge-mode directly attached interface when no mode is specified)? - how can I use virsh to discover machines with vepa-mode interfaces (virsh domiflist <domain> does not return the interface mode)? - can I change the interface type at runtime (virt-xml <domain> --edit --network type=direct,source.mode=bridge works for inactive domains only)? 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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