- Users - libvirt List Archives

PCI/GPU Passthrough with xen
by Christoph 14 Feb '20

14 Feb '20

Hi All, it is possible to use pci/gpu passthrough with xen and libvirt? If yes, how is the syntax? Can I get an example? -- ------ Greetz

3 6

ERROR Could not find an installable distribution at ....
by Kaushal Shriyan 14 Feb '20

14 Feb '20

Hi, I am trying to set up alpine Linux Guest OS using the below command #virt-install --name=mfecdrupalalphine --file=/linuxkvmguestosdisk/var/lib/libvirt/images/mfecdrupalalphine.img --file-size=100 --nonsparse --vcpus=2 --ram=6096 --network=bridge:br0 --os-type=linux --os-variant=alpinelinux3.8 --graphics none --location=/linuxkvmguestosdisk/var/lib/libvirt/isos/alpine-standard-3.11.3-x86_64.iso --extra-args="console=ttyS0" Starting install... Retrieving file .treeinfo... | 0 B 00:00:00 Retrieving file content... | 0 B 00:00:00 ERROR Could not find an installable distribution at '/linuxkvmguestosdisk/var/lib/libvirt/isos/alpine-standard-3.11.3-x86_64.iso': The URL could not be accessed, maybe you mistyped? The location must be the root directory of an install tree. See virt-install man page for various distro examples. Domain installation does not appear to have been successful. If it was, you can restart your domain by running: virsh --connect qemu:///system start mfecdrupalalphine otherwise, please restart your installation. The iso file do exist as per the below details ls -l /linuxkvmguestosdisk/var/lib/libvirt/isos/alpine-standard-3.11.3-x86_64.iso -rw-r--r-- 1 root root 127926272 Feb 12 17:49 /linuxkvmguestosdisk/var/lib/libvirt/isos/alpine-standard-3.11.3-x86_64.iso # Any clue? I look forward to hearing from you and thanks in advance. Best Regards, Kaushal

2 1

problems with understanding of the memory parameters in the xml file
by Lentes, Bernd 13 Feb '20

13 Feb '20

Hi guys, despite reading hours and hours in the internet i'm still struggling with "memory", "currentmemory" and "maxMemory". Maybe you can help me to sort it out. My idea is that a guest has an initial value of memory (which "memory" seems to be) when booting. We have some Windows 10 guests which calculate some stuff and i would like to increase memory during runtime until it reaches a fixed maximum value. My hope was that a higher "maxMemory" could solve this, that the guest claims more memory and gets it. I didn't get it. Is my idea wrong ? Do i need a balloon driver for that ? What i find concerning ballooning is that it doesn't work automatically but has to be adjusted manually. Is that right ? Balloon drivers for windows are available. Is my idea right, does that work basically ? If yes how do i have to set the parameters ? Is the memory released after the guest has e.g. finished his calculation ? Does that work automatically or do i have to adjust that manually ? Thanks. Bernd -- Bernd Lentes Systemadministration Institute for Metabolism and Cell Death (MCD) Building 35.34 - Raum 208 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 Perfekt ist wer keine Fehler macht Also sind Tote perfekt 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

2 2

does the guest have a snapshot ?
by Lentes, Bernd 10 Feb '20

10 Feb '20

Hi, i'm cuurently a bit confused if a guest does have a valid snapshot or not. This is the xml: ... <disk type='file' device='disk'> <driver name='qemu' type='qcow2'/> <source file='/var/lib/libvirt/images/crispor_1604/crispor_1604.sn'/> <backingStore type='file' index='1'> <format type='raw'/> <source file='/var/lib/libvirt/images/crispor_1604/crispor_1604.img'/> <backingStore/> </backingStore> <target dev='vda' bus='virtio'/> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </disk> ... both files are currently in access by the respective qemu process. lsof: qemu-kvm 19533 root 13u REG 253,0 29761732608 12091393 /var/lib/libvirt/images/crispor_1604/crispor_1604.sn qemu-kvm 19533 root 14r REG 253,0 111561775513 44793857 /var/lib/libvirt/images/crispor_1604/crispor_1604.img Here are both files: pc60181:/var/lib/libvirt/images/crispor_1604 # ll ... -rw------- 1 root root 111561775513 Oct 22 15:23 crispor_1604.img -rw-r--r-- 1 root root 29761732608 Feb 7 15:13 crispor_1604.sn crispor_1604.sn has a recent timestamp. The snapshot is currently in use: virsh # domblklist crispor_1604 Target Source ------------------------------------------------ vda /var/lib/libvirt/images/crispor_1604/crispor_1604.sn But virsh does not show any snapshot: virsh # snapshot-list crispor_1604 Name Creation Time State ------------------------------------------------------------ So i'm a bit confused. Does it have a valid snapshot or not. How can i find out and how can i get rid of it ? Thanks. Bernd -- Bernd Lentes Systemadministration Institute for Metabolism and Cell Death (MCD) Building 35.34 - Raum 208 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 Perfekt ist wer keine Fehler macht Also sind Tote perfekt 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

2 4

No DHCP on default network when guest has multiple interfaces
by Patrick O'Neill 07 Feb '20

07 Feb '20

Hello, I am trying to boot a VM in libvirt that has 2 interfaces. The first interface is connected to the default network and the second connects to a bridge interface on the host. When the VM boots the first interface doesn't receive an IP address from DHCP. It works when the VM only has one interface though. If I login to the VM using virsh console I noticed that in NetworkManager the connection name and device are mixed [root@localhost ~]# nmcli con show NAME UUID TYPE DEVICE eth0 cc31f368-0a43-4c85-bd15-6aaa3ca23b3d ethernet eth1 If I run 'dhclient eth0' the interface gets an IP address from the default network as expected. [root@localhost ~]# dhclient eth0 [root@localhost ~]# 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 valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 52:54:00:00:01:00 brd ff:ff:ff:ff:ff:ff inet 192.168.122.10/24 brd 192.168.122.255 scope global dynamic eth0 valid_lft 3599sec preferred_lft 3599sec 3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 52:54:00:48:e3:b8 brd ff:ff:ff:ff:ff:ff inet6 fe80::5054:ff:fe48:e3b8/64 scope link noprefixroute valid_lft forever preferred_lft forever The VM is created using the following command virt-install --import --name ${VM_HOST_NAME} \ --memory 2048 --vcpus 2 --cpu host \ --disk path=/var/lib/libvirt/images/${VM_HOST_NAME}.qcow2,format=qcow2,bus=virtio \ --network network=default \ --network bridge=bridge0,model=virtio \ --os-type=linux \ --os-variant=rhel7.6 \ --graphics none Any ideas what could cause this problem? The guest OS is CentOS 7.7 and the host is CentOS 8, but I have the same problem with a CentOS 7 hypervisor.

2 1

Does Libvirt's json parser support single quoted string in qmp json string?
by Peter Luo 05 Feb '20

05 Feb '20

Hi All, I’m using qmp command via “virsh qemu-monitor-command” to perform block related jobs. And in my case, I execute block-commit to commit the changes in the top image to the base image which is encrypted. So in the base parameter, I need a json string which is single quoted to support the encryption parameters. However, the virsh is failed to parse the whole json qmp command. Attempt 1: Single quote without backflash, failed root@host:~# virsh qemu-monitor-command i-9wdfw2x8 "{\"execute\": \"block-commit\", \"arguments\": { \"device\": \"drive-virtio-disk2\", \"job-id\": \"job100\", \"base\":'json:{\"encrypt.key-secret\":\"vol-38973xjl.secret\",\"driver\":\"qcow2\",\"file\":{\"driver\":\"file\",\"filename\":\"/pitrix/data/container/vol-38973xjl.img\"}}', \"top\": \"/pitrix/data/container/vol-38973xjl_ss-2tw7v0mm.img\"}}" error: internal error: cannot parse json {"execute": "block-commit", "arguments": { "device": "drive-virtio-disk2", "job-id": "job100", "base":'json:{"encrypt.key-secret":"vol-38973xjl.secret","driver":"qcow2","file":{"driver":"file","filename":"/pitrix/data/container/vol-38973xjl.img"}}', "top": "/pitrix/data/container/vol-38973xjl_ss-2tw7v0mm.img"}}: lexical error: invalid char in json text. , "job-id": "job100", "base":'json:{"encrypt.key-secret":"vo (right here) ------^ Attempt 2: Single quote with backflash, failed root@host:~# virsh qemu-monitor-command i-9wdfw2x8 "{\"execute\": \"block-commit\", \"arguments\": { \"device\": \"drive-virtio-disk2\", \"job-id\": \"job100\", \"base\":\'json:{\"encrypt.key-secret\":\"vol-38973xjl.secret\",\"driver\":\"qcow2\",\"file\":{\"driver\":\"file\",\"filename\":\"/pitrix/data/container/vol-38973xjl.img\"}}\', \"top\": \"/pitrix/data/container/vol-38973xjl_ss-2tw7v0mm.img\"}}" error: internal error: cannot parse json {"execute": "block-commit", "arguments": { "device": "drive-virtio-disk2", "job-id": "job100", "base":\'json:{"encrypt.key-secret":"vol-38973xjl.secret","driver":"qcow2","file":{"driver":"file","filename":"/pitrix/data/container/vol-38973xjl.img"}}\', "top": "/pitrix/data/container/vol-38973xjl_ss-2tw7v0mm.img"}}: lexical error: invalid char in json text. , "job-id": "job100", "base":\'json:{"encrypt.key-secret":"v (right here) ------^ My libvirt version is 5.7.0, libyajl is 2.1.0. Thanks, Peter Luo

6 9

USB devices with same vendor:product id
by Maxime Accadia 03 Feb '20

03 Feb '20

Hi, We have a VM with several USB devices attached. Everything works well, but sometimes, after a reboot of the host, some usb device get a different bus/device number and that prevent the reboot of the VM : ------- error: Failed to start domain xxx error: internal error: Did not find USB device 04b9:0300 bus:1 device:5 ------- I guess this is because we have multiple usb devices with the same vendor/product ID : ------- <hostdev mode='subsystem' type='usb' managed='yes'> <source> <vendor id='0x04b9'/> <product id='0x0300'/> <address bus='2' device='4'/> </source> <alias name='hostdev0'/> <address type='usb' bus='0' port='2'/> </hostdev> <hostdev mode='subsystem' type='usb' managed='yes'> <source> <vendor id='0x0529'/> <product id='0x0001'/> <address bus='1' device='7'/> </source> <alias name='hostdev1'/> <address type='usb' bus='0' port='1.2'/> </hostdev> <hostdev mode='subsystem' type='usb' managed='yes'> <source> <vendor id='0x0529'/> <product id='0x0001'/> <address bus='2' device='3'/> </source> <alias name='hostdev2'/> <address type='usb' bus='0' port='1.4'/> </hostdev> <hostdev mode='subsystem' type='usb' managed='yes'> <source> <vendor id='0x04b9'/> <product id='0x0300'/> <address bus='1' device='6'/> </source> <alias name='hostdev3'/> <address type='usb' bus='0' port='1.1'/> </hostdev> ------- Any idea on how to handle this case ? We were thinking about using udev, but it seems that libvirt only supports vendor/id (not unique in our case) and bus/device (not predictable) to identify usb devices. Thanks, Maxime Accadia P.S. We use libvirt 4.0.0 on Ubuntu 18.04

3 4

Re: Does Libvirt's json parser support single quoted string in qmp json string?
by Peter Luo 31 Jan '20

31 Jan '20

Hi Peter Krempa, Thanks for your quick response, yes, I know since libvirt 5.8, the -blockdev is used for disk by default. However we have to maintain the old releases for the production environment for a while, so I still need use the old way to create the disk. >"base" argument must be a string. this means you need double quotes in >JSON ("). You also must properly escape any further JSON. > Do you mean the base argument need be formatted like below? \"base\":\"json:{\"encrypt.key-secret\":\"vol-38973xjl.secret\",\"driver\":\"qcow2\",\"file\":{\"driver\":\"file\",\"filename\":\"/pitrix/data/container/vol-38973xjl.img\"}}\" Please help me to point out where the examples are located? I did take a quick look at those test files, but no one seems to be matched with my case. Thanks, Peter Luo On 31/1/20, 6:52 PM, "Peter Krempa" <pkrempa(a)redhat.com> wrote: On Fri, Jan 31, 2020 at 18:38:33 +0800, Peter Luo wrote: > Hi All, > > > > I’m using qmp command via “virsh qemu-monitor-command” to perform block related jobs. > > And in my case, I execute block-commit to commit the changes in the top image to the base image which is encrypted. > > So in the base parameter, I need a json string which is single quoted to support the encryption parameters. > > However, the virsh is failed to parse the whole json qmp command. None of the above should be required with libvirt-5.10 and later when using qemu-4.2. Those two versions start using blockdev way of specifying images and encrypted images are supported. Please consider using libvirt-6.0 though as there are few fixes for blockdev. > > > > Attempt 1: Single quote without backflash, failed > > root@host:~# virsh qemu-monitor-command i-9wdfw2x8 "{\"execute\": \"block-commit\", \"arguments\": { \"device\": \"drive-virtio-disk2\", \"job-id\": \"job100\", \"base\":'json:{\"encrypt.key-secret\":\"vol-38973xjl.secret\",\"driver\":\"qcow2\",\"file\":{\"driver\":\"file\",\"filename\":\"/pitrix/data/container/vol-38973xjl.img\"}}', \"top\": \"/pitrix/data/container/vol-38973xjl_ss-2tw7v0mm.img\"}}" > > error: internal error: cannot parse json {"execute": "block-commit", "arguments": { "device": "drive-virtio-disk2", "job-id": "job100", "base":'json:{"encrypt.key-secret":"vol-38973xjl.secret","driver":"qcow2","file":{"driver":"file","filename":"/pitrix/data/container/vol-38973xjl.img"}}', "top": "/pitrix/data/container/vol-38973xjl_ss-2tw7v0mm.img"}}: lexical error: invalid char in json text. > > , "job-id": "job100", "base":'json:{"encrypt.key-secret":"vo "base" argument must be a string. this means you need double quotes in JSON ("). You also must properly escape any further JSON. Given that libvirt now supports the operation natively I'll refrain from elaborating on how to properly escape JSON to contain JSON strings, but there are few examples in the test suite. But please use the upstream supported way instead.

2 1

Detecting of features of VMs
by Peter Krempa 29 Jan '20

29 Jan '20

Hi, I was asked by Nir and Eyal of the oVirt project on how to detect whether a certain feature is supported by libvirt. As I thought it might be better to document this publically rather than being lost in a private thread I'm posting this to libvirt-users. The specific question will be answered below. --- There are currently two interfaces which allow discovery of libvirts and in turn qemu's capabilities. Both return an XML which describes various aspects of the hosts or VMs capabilities. virConnectGetCapabilities(conn) https://libvirt.org/formatcaps.html The XML returned by this API describes mostly the host itself, the CPU, NUMA topology, security driver support, migration features but also describes guests architectures supported by the guest. In case of the qemu driver the guest section describes some of the aspects and configurations supported by the default qemu binary, the machine types and virtualization types it supports. Additionally the <features> section describes support for some long-existing features such as ACPI, APIC and disk snapshots. As these features are supported for a long time, it can be assumed that they are present (at least in case of the qemu driver) when the second API is present. Now while the virConnectGetCapabilities API provides mostly useful information about the host, the limitation of not being able to report information about specific qemu binaries or machine types lead to introduction. virConnectGetDomainCapabilities(conn, emulator_binary_path, architecture, machine_type, virt_type, flags) https://libvirt.org/formatdomaincaps.html The XML returned by this API describes the capabilities of an VM which would be started using the parameters given to the API (note that if the parameters are NULL a default is provided). The <os> subelement describes supported OS loader types and firmware binaries. <cpu> describes which CPU models are supported by the emulator and also the CPU which would be used if 'host-model' is selected as the CPU model. The <devices> section describes models and some properties of devices supported by the VM. The 'enum's reported in this XML map to supported values of some of the fields we report the possible configurations for. Note that these values are reported individually and all combinations aren't necessarily supported. The last section 'features' describes whether some high-level features supported by such a VM. The features themselves are described in the documentation above. Note that the entries into 'features' are added arbitrarily depending on whether a feature is deemed important enough to be exposed. So please feel free to report if anything is missing or it would be helpful if we reported any feature. --- Now specifically to the question: I was asked on when it's safe to pass VIR_DOMAIN_UNDEFINE_CHECKPOINTS_METADATA to virDomainUndefine. In this case it's safe to pass it if <features> contains the <backup> element regardless of the value of 'supported' attribute. I'll also mention this in the documentation of the domain caps XML.

2 1

Host CPU usage high on guest network load (macvtap).
by André Malm 28 Jan '20

28 Jan '20

Hello, Is it reasonable for one CPU on the host to be loaded 20-30% on 100 mbps download in a guest? There is barely any (1-2%) load in the guest. The host is running ubuntu 18.04 on an Intel i7-7700K, virtualization etc is enabled. Everything except host load on guest network activity is fine. This is how i setup the network with virt-install: --network type=direct,source=enp1s0,source_mode=bridge,model=virtio,mac=00:11:22:33:44:55 In the guest (ubuntu18.04 cloud minimal) i run a simple wget, setting mode to vepa still works but the cpu load is the same.

1 0

Emulation packages for Centos8
by Mauricio Tavares 28 Jan '20

28 Jan '20

So I was looking for the qemu-system-ppc so I could emulate that cpu in my Intel I7 centos8 box. So far I found that available for fedora (and ubuntu) but not centos. Does anyone have a suggestion for where (repo) I can get said package?

1 0

NFS and unsafe migration
by Gionatan Danti 28 Jan '20

28 Jan '20

Hi all, I have a question about NFS datastore and unsafe migration. When migrating a virtual machine having a virtio disk in writeback cache between two hosts sharing a single NFS datastore, I get the following error: "Unsafe migration: Migration may lead to data corruption if disks use cache != none or cache != directsync" I understand why libvirt alerts for unsafe migration in cases where no coherency is enfoced by the underlying system; however, is it really the case for nfs? From what I know (and from the man page), by default nfs has open-to-close consistency, which seems quite right for migrating a virtual machine between (as only one host at a time reads/writes/locks the virtual disk files). I know that I can simply use cache=none to let the problem go away; however, this significantly impairs performance when used on nfs. Am I missing something? 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

1 0

KVM not available on system bus
by Kasper Laudrup 28 Jan '20

28 Jan '20

Hi libvirt-users, Hope this is the right place to ask, otherwise please point me in the right direction. I have a libvirt virtual machine running on the session bus that I would like to access through SSH. I have previously done so using X11 forwarding and while it works, it is very sluggish with the connection I have. I recently learned that you can access the virtual machine with virt-viewer through SSH which should perform much better. Unfortunately, my virtual machine is currently running on the session bus and that doesn't seem to be supported (please do correct if I'm wrong here). It doesn't really matter to much if the VM is running on the system bus or session bus, I just prefer running things as a non privileged user for all the obvious reasons, so that's where I created the VM initially. I tried to follow this guide to move my VM to the system bus. Running `sudo virsh define vm.xml` fails with: error: invalid argument: could not find capabilities for arch=x86_64 domaintype=kvm Digging a bit further into it, I figured out that the cause of the error message is, that I for some reason do not have KVM acceleration support when running VMs on the system bus (as root) running my VM on the session bus as a normal user (with the correct group membership) works fine. Trying to launch virt-manager as root verifies that, as creating a new VM warns me that I do not have KVM support. I'm fairly lost as to what to do from here. I must admit I remember struggling a bit to get the virtual machine to run with KVM support on the session bus in the first place, but have completely forgotten what the problem and resolution was. I'm using Debian stable (Buster) with standard package versions: QEMU 3.1.0 libvirt 5.0.0 Any kind of help or input would be greatly appreciated. Thanks a lot and kind regards, Kasper Laudrup

2 2

VM crash, partitiontable deleted CPU 1/KVM[2867866]: segfault at 2 ip 0000560cffe03757 sp 00007f0e8babaeb0 error 4 in qemu-system-x86_64
by Oliver Dzombic 27 Jan '20

27 Jan '20

Hi, Got from a running machine suddenly: [859069.022739] CPU 1/KVM[2867866]: segfault at 2 ip 0000560cffe03757 sp 00007f0e8babaeb0 error 4 in qemu-system-x86_64[560cffbd4000+45d000] [859069.022749] Code: 00 00 00 41 57 41 56 41 55 41 54 49 89 cc b9 a2 03 00 00 55 48 89 f5 48 8d 35 1c 35 29 00 53 48 89 fb 48 83 c7 38 48 83 ec 38 <44> 0f b7 52 02 4c 8b 7a 08 4c 89 44 24 08 4c 8d 05 b4 08 29 00 45 [859087.661975] device k1806-YcXLF left promiscuous mode # qemu-system-x86_64 --version QEMU emulator version 4.2.0 (qemu-4.2.0-2.fc31) Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers # virsh -V Virsh command line tool of libvirt 6.0.0 See web site at https://libvirt.org/ Compiled with support for: Hypervisors: QEMU/KVM LXC LibXL OpenVZ VMware VirtualBox ESX Hyper-V Test Networking: Remote Network Bridging Interface netcf Nwfilter VirtualPort Storage: Dir Disk Filesystem SCSI Multipath iSCSI LVM RBD Sheepdog Gluster ZFS Miscellaneous: Daemon Nodedev SELinux Secrets Debug DTrace Readline After that the partition table of the zfs volume was cleared. I also opened a bug report with all informations i could get so far: https://bugzilla.redhat.com/show_bug.cgi?id=1795082 I am thankful for any idea / suggestion. Thank you -- Mit freundlichen Gruessen / Best regards Oliver Dzombic Layer7 Networks mailto:info@layer7.net Anschrift: Layer7 Networks GmbH Zum Sonnenberg 1-3 63571 Gelnhausen HRB 96293 beim Amtsgericht Hanau Geschäftsführung: Oliver Dzombic UST ID: DE259845632

1 0

VM crash, partitiontable deleted CPU 1/KVM[2867866]: segfault at 2 ip 0000560cffe03757 sp 00007f0e8babaeb0 error 4 in qemu-system-x86_64
by Oliver Dzombic 27 Jan '20

27 Jan '20

Hi, Got from a running machine suddenly: [859069.022739] CPU 1/KVM[2867866]: segfault at 2 ip 0000560cffe03757 sp 00007f0e8babaeb0 error 4 in qemu-system-x86_64[560cffbd4000+45d000] [859069.022749] Code: 00 00 00 41 57 41 56 41 55 41 54 49 89 cc b9 a2 03 00 00 55 48 89 f5 48 8d 35 1c 35 29 00 53 48 89 fb 48 83 c7 38 48 83 ec 38 <44> 0f b7 52 02 4c 8b 7a 08 4c 89 44 24 08 4c 8d 05 b4 08 29 00 45 [859087.661975] device k1806-YcXLF left promiscuous mode # qemu-system-x86_64 --version QEMU emulator version 4.2.0 (qemu-4.2.0-2.fc31) Copyright (c) 2003-2019 Fabrice Bellard and the QEMU Project developers # virsh -V Virsh command line tool of libvirt 6.0.0 See web site at https://libvirt.org/ Compiled with support for: Hypervisors: QEMU/KVM LXC LibXL OpenVZ VMware VirtualBox ESX Hyper-V Test Networking: Remote Network Bridging Interface netcf Nwfilter VirtualPort Storage: Dir Disk Filesystem SCSI Multipath iSCSI LVM RBD Sheepdog Gluster ZFS Miscellaneous: Daemon Nodedev SELinux Secrets Debug DTrace Readline After that the partition table of the zfs volume was cleared. I also opened a bug report with all informations i could get so far: https://bugzilla.redhat.com/show_bug.cgi?id=1795082 I am thankful for any idea / suggestion. Thank you ! -- Mit freundlichen Gruessen / Best regards Oliver Dzombic Layer7 Networks mailto:info@layer7.net Anschrift: Layer7 Networks GmbH Zum Sonnenberg 1-3 63571 Gelnhausen HRB 96293 beim Amtsgericht Hanau Geschäftsführung: Oliver Dzombic UST ID: DE259845632

1 0

Prevent the firewall from being compromised through libvirtd
by Thomas Luening 27 Jan '20

27 Jan '20

Hello @ all The libvirt-daemon compromises the packet-filtering-rules at daemon-startup, before any VM is started. To prevent this, I first have create a hook-script which deletes existing rules, but apparently these rules are set after the hook. Removing the defined networks was no solution either. Worst of all is, a service restart of the daemon may even completely neutralize the firewall. Is there a solution to prevent this undesirable behavior? No matter how or who what do or with what network configuration a VM is started, the daemon must not compromise the firewall, by altering them. The Firewall is untouchable and taboo. What can I do to disable that? Thank you! Best Regards Tom $ dpkg -l libvirt-daemon ||/ Name Version Architektur Beschreibung +++-=========================-============-============-================================== ii libvirt-daemon 5.0.0-4 amd64 Virtualization daemon $ lsb_release -a Distributor ID: Debian Description: Debian GNU/Linux 10 (buster) Release: 10 Codename: buster

2 1

Repetitive RBD disk definitions
by wferi＠niif.hu 24 Jan '20

24 Jan '20

Hi, I'm using libvirt 5.0.0 on a Ceph cluster. The VM disks are all from the same Ceph pool, so all my <disk> elements are basically the same: <disk type="network" device="disk"> <driver name="qemu" type="raw" cache="none"/> <source protocol="rbd" name="vmdisks/VOLNAME"> <host name="x.y.z.1" port="6789"/> <host name="x.y.z.2" port="6789"/> <host name="x.y.z.3" port="6789"/> </source> <auth username="libvirt"> <secret type="ceph" usage="libvirt_key"/> </auth> <target dev="vdX"/> </disk> ... apart from the VOLNAME and vdX words. Is there a way to factor out (at least part of) the common stuff? This repetition isn't totally unmanageable, just not pretty. Creating a libvirt storage pool seemed like a good solution at first, but I couldn't find a way to "instantiate" volumes in the domain XML (and defining them cluster-wide would mean duplicating what Ceph does, which I'd rather avoid). -- I'd be grateful for any ideas, Feri.

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virsh vol-download uses a lot of memory
by R. Diez 23 Jan '20

23 Jan '20

Hi all: I am using the libvirt version that comes with Ubuntu 18.04.3 LTS. I have written a script that backs up my virtual machines every night. I want to limit the amount of memory that this backup operation consumes, mainly to prevent page cache thrashing. I have described the Linux page cache thrashing issue in detail here: http://rdiez.shoutwiki.com/wiki/Today%27s_Operating_Systems_are_still_incre… The VM virtual disk weighs 140 GB at the moment. I thought 500 MiB of RAM should be more than enough to back it up, so I added the following options to the systemd service file associated to the systemd timer I am using: MemoryLimit=500M However, the OOM is killing "virsh vol-download": Jan 21 23:40:00 GS-CEL-L kernel: [55535.913525] [ pid ] uid tgid total_vm rss pgtables_bytes swapents oom_score_adj name Jan 21 23:40:00 GS-CEL-L kernel: [55535.913527] [ 13232] 1000 13232 5030 786 77824 103 0 BackupWindows10 Jan 21 23:40:00 GS-CEL-L kernel: [55535.913528] [ 13267] 1000 13267 5063 567 73728 132 0 BackupWindows10 Jan 21 23:40:00 GS-CEL-L kernel: [55535.913529] [ 13421] 1000 13421 5063 458 73728 132 0 BackupWindows10 Jan 21 23:40:00 GS-CEL-L kernel: [55535.913530] [ 13428] 1000 13428 712847 124686 5586944 523997 0 virsh Jan 21 23:40:00 GS-CEL-L kernel: [55535.913532] oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=/,mems_allowed=0,oom_memcg=/system.slice/VmBackup.service,task_memcg=/system.slice/VmBackup.service,task=virsh,pid=13428,uid=1000 Jan 21 23:40:00 GS-CEL-L kernel: [55535.913538] Memory cgroup out of memory: Killed process 13428 (virsh) total-vm:2851388kB, anon-rss:486180kB, file-rss:12564kB, shmem-rss:0kB I wonder why "virsh vol-download" needs so much RAM. It does not get killed straight away, it takes a few minutes to get killed. It starts using a VMSIZE of around 295 MiB, which is not really frugal for a file download operation, but then it grows and grows. Note that the virtual machine is not running (shut off) while doing the backup. Last time I tried with an increased memory limit of 5G, "virsh vol-download" was killed when using 7,4 G, and the partially-downloaded volume file weighted 60G. Therefore, it looks like "virsh vol-download" is using a percentage of the downloaded size in RAM. Is there a way to make "virsh vol-download" use less memory? Thanks in advance, rdiez

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How to detect completion of a paused VM migration on the destination?
by Milan Zamazal 22 Jan '20

22 Jan '20

Hi, when a normally running VM is migrated, libvirt sends VIR_DOMAIN_EVENT_RESUMED_MIGRATED event on the destination once the migration completes. I can see that when a paused VM is migrated, libvirt sends VIR_DOMAIN_EVENT_SUSPENDED_PAUSED instead. Since there seems to be nothing migration specific about VIR_DOMAIN_EVENT_SUSPENDED_PAUSED event, my question is: Is it safe to assume on the destination that this event signals completion of the incoming migration (unless VIR_DOMAIN_EVENT_RESUMED_MIGRATED is received before)? Thanks, Milan

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Testing mail delivery
by dberrange＠yahoo.com 22 Jan '20

22 Jan '20

We continue to have problems with mail delivery, especially to Yahoo addresses. This mail is a test to investigate delivery behaviour, please ignore this mail thread. Daniel

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[libvirt-users] Connecting a VM to an existing OVS bridge
by Amir Sela 20 Jan '20

20 Jan '20

Hi, I have an existing OVS bridge, that I can see in ovs-vsctl and use for other purposes. I've edited the machine's XML as instructed in http://docs.openvswitch.org/en/latest/howto/libvirt/ When I try to start the VM, i get error: Cannot get interface MTU on 'ovsbr': No such device Any ideas? (Note: I can't see the ovs switch in brctl show or any other regular kernel tool, should it appear there?) Versions: openvswitch-2.10.1-3.fc30.x86_64 libvirt-daemon-5.1.0-9.fc30.x86_64 Thanks!

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USB-hotplugging fails with "failed to load cgroup BPF prog: Operation not permitted" on cgroups v2
by Pol Van Aubel 20 Jan '20

20 Jan '20

Hi all, I've disabled cgroups v1 on my system with the kernel boot option "systemd.unified_cgroup_hierarchy=1". Since doing so, USB hotplugging fails to work, seemingly due to a permissions problem with BPF. Please note that the technique I'm going to describe worked just fine for hotplugging USB devices to running domains until this change. Attaching / detaching USB devices when the domain is down still works as expected. I get the same error when attaching a device in virt-manager, as I do when running the following command: sudo virsh attach-device wenger /dev/stdin --persistent <<END <hostdev mode='subsystem' type='usb' managed='yes'> <source startupPolicy='optional'> <vendor id='0x046d' /> <product id='0xc215' /> </source> </hostdev> END This returns error: Failed to attach device from /dev/stdin error: failed to load cgroup BPF prog: Operation not permitted virt-manager returns basically the same error, but for completeness' sake, here it is: failed to load cgroup BPF prog: Operation not permitted Traceback (most recent call last): File "/usr/share/virt-manager/virtManager/addhardware.py", line 1327, in _add_device self.vm.attach_device(dev) File "/usr/share/virt-manager/virtManager/object/domain.py", line 920, in attach_device self._backend.attachDevice(devxml) File "/usr/lib/python3.8/site-packages/libvirt.py", line 590, in attachDevice if ret == -1: raise libvirtError ('virDomainAttachDevice() failed', dom=self) libvirt.libvirtError: failed to load cgroup BPF prog: Operation not permitted Now, libvirtd is running as root, so I don't understand why any operation on BPF programs is not permitted. I've dug into libvirt's code a bit to see what is throwing this error and it boils down to <https://github.com/libvirt/libvirt/blob/7d608469621a3fda72dff2a89308e68cc9f…> and <https://github.com/libvirt/libvirt/blob/02bf7cc68bfc76242f02d23e73cad36618f…> but I have no clue what that syscall is doing, so that's where my debugging capability basically ends. Maybe this is something as simple as setting the right ACL somewhere. I haven't touched /etc/libvirt/qemu.conf except for setting nvram. There *is* something about cgroup_device_acl there but afaict that's for cgroups v1, when there was still a device cgroup controller. Any help would be greatly appreciated. Domain log files: Upon execution of the above commands, nothing gets added to the domain log in /var/log/qemu/wenger.log, so I've decided they're likely irrelevant to the issue. Please ask for any additional info required. System information: Arch Linux, (normal) kernel 5.4.11 libvirt 5.10.0 qemu 4.2.0, using KVM. Host system is x86_64 on an intel 5820k. Guest system is probably irrelevant, but is Windows 10 on the same. Possibly relevant kernel build options: $ zgrep BPF /proc/config.gz [22:55:52]: zgrep BPF /proc/config.gz CONFIG_CGROUP_BPF=y CONFIG_BPF=y CONFIG_BPF_SYSCALL=y CONFIG_BPF_JIT_ALWAYS_ON=y CONFIG_IPV6_SEG6_BPF=y CONFIG_NETFILTER_XT_MATCH_BPF=m # CONFIG_BPFILTER is not set CONFIG_NET_CLS_BPF=m CONFIG_NET_ACT_BPF=m CONFIG_BPF_JIT=y CONFIG_BPF_STREAM_PARSER=y CONFIG_LWTUNNEL_BPF=y CONFIG_HAVE_EBPF_JIT=y CONFIG_BPF_EVENTS=y # CONFIG_BPF_KPROBE_OVERRIDE is not set # CONFIG_TEST_BPF is not set Regards, Pol Van Aubel

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Prevent virsh live migration from copy zero -- increment copy on live migration possible ?
by Oliver Dzombic 18 Jan '20

18 Jan '20

Hi, i am doing a live migration like this: [root@nodeA ~]#virsh migrate --copy-storage-all --verbose --live kvm1776 qemu+ssh://nodeb/system which works fine with libvirt version 6. The zfs backed hdd is 100G, while its thin-provisioned. The real data on it is 1G. So even its 1G of data, virsh copies a lot of zero's as it seems. There is a lot of HDD IO and network activity, but in fact the size at the target volume does not grow ( since there are no more data ). After it successfully finished the copy, i tried what will happen with the --copy-storage-inc parameter: [root@nodeB ~]# virsh migrate --copy-storage-inc --verbose --live kvm1776 qemu+ssh://nodea/system But that didnt change anything. Even both volumes are identical now, again the whole copy of all ( non existing ) 100GB. Is there any way to make libvirt just copy real data and not Zero's that actually do not exist and causing network and HDD IO traffic ? Thank you ! -- Mit freundlichen Gruessen / Best regards Oliver Dzombic Layer7 Networks mailto:info@layer7.net Anschrift: Layer7 Networks GmbH Zum Sonnenberg 1-3 63571 Gelnhausen HRB 96293 beim Amtsgericht Hanau Geschäftsführung: Oliver Dzombic UST ID: DE259845632

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Bridge-less VM
by Rob Roschewsk 17 Jan '20

17 Jan '20

I'm trying to create a free standing VM that doesn't connect to a bridge. This is supposedly do able according to the WIKI: https://libvirt.org/formatdomain.html#elementsNICSEthernet But with a config similar to: <interface type='ethernet'> <target dev='mytap1' managed='no'/> <model type='virtio'/> </interface> When starting the domain I get the error: error: internal error: process exited while connecting to monitor: 2020-01-16T18:08:04.788860Z qemu-system-x86_64: -netdev tap,id=hostnet0,vhost=on,vhostfd=26: could not open /dev/net/tun: Operation not permitted Checked permissions on /dev/net/tunand it's 666 If I just configure it as a "bridge" connection the domain starts. Then I can use brctl to remove it from the bridge to get what I want. That just proves it possible but with extra steps (Shout out to Rick and Morty) Thoughts?? Running Ubuntu 16.04.1 Kernel 4.15.0-74 libvirt 1.3.1-1ubuntu10.27 qemu 1:2.5+dfsg-5ubuntu10.41 Thanks, --> Rob

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Volume file permissions and huge volume downloads
by R. Diez 17 Jan '20

17 Jan '20

Hi all: I am using the libvirt version that comes with Ubuntu 18.04.3 LTS. I want to backup a virtual machine in a foolproof way: - Gracefully shutdown the VM. - Backup the disk image. - Restart the VM. I wrote the following script to do that: https://github.com/rdiez/Tools/blob/master/VirtualMachineManager/BackupVm.sh Writing that script was difficult enough because of the virsh limitations (in my opinion) described in the comments. But at least it works. The main problem is that libvirt sets the ownership and permissions of volume files in such a way that a standard user cannot access them, even if it is member of the 'libvirt' group. While the VM is running, volume file permissions are like this: -rw-r----- 1 libvirt-qemu kvm [...] /var/lib/libvirt/images/YourVmDisk.qcow2 When the VM is shutoff: -rw-r----- 1 root root [...] /var/lib/libvirt/images/YourVmDisk.qcow2 The trouble is, I want to access that .qcow2 file when the VM is shutoff. I would really like not to run my script as root. I could not find a way to specify the permissions for the .qcow2 files, so I tried editing the group ownership for the whole pool: virsh pool-edit default <target> <path>/var/lib/libvirt/images</path> <permissions> <mode>0711</mode> <owner>0</owner> <group>131</group> </permissions> </target> Setting <group> to "libvirt" did not work (XML validation error), so I tried the numeric ID of that group (131). That did not work. When I restart libvirt with "service libvirtd restart", my changes to the pool XML file disappear (!). Later on, I found out that you can download a volume like this: virsh vol-download --pool default YourVmDisk.qcow2 YourVmDisk.qcow2 The trouble is that I created the virtual disk with a maximum size of 120 GB. I copied it around a few times, so I think it has lost any "sparseness" inside. Command "virsh vol-download" takes ages and downloads all those 120 GB. My script uses "qemu-img convert", which discards all unused space and writes just 17 GB of data, and that is without turning compression on. The whole backup takes seconds instead of minutes. Can somebody help me with these issues? Thanks in advance, rdiez

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