- Users - libvirt List Archives

Debugging hanging libvirt
by Tobias Hofmann (tohofman) 04 Apr '22

04 Apr '22

Hello all, I have a system with one VM running. After some time the VM needs to be temporarily stopped and started again. This start operation fails and from that point on any virsh command is hanging and does not execute. This issue is reproducible and I have already figured out that restarting libvirtd resolves this issue. However, I’m now trying to understand why it’s getting stuck in the first place. I try not to get too much into detail because I think this would be more confusing than it would actually help to understand the problem. In general, I’m wondering what approach you should follow to debug why libvirt gets stuck. Online I’ve read that you should run this command: `# gdb -batch -p $(pidof libvirtd) -ex 't a a bt f'`. I’ve run that command and attached the output to this mail. However, I have to admit that I have no idea what to do with it. System related info: * OS: CentOS 7.8.2003 * libvirt version: 4.5.0-33 Appreciate any help here! Thank you! Tobias

4 4

Networking on macOS host, without TunTap
by Carl Winbäck 31 Mar '22

31 Mar '22

Dear libvirt users, I’m trying to get the following setup up and running: libvirt+qemu on a macOS Monterey host, with a Debian 11 guest. The domain type is hvf. The thing I’m struggling with now is how to configure networking in a sane way. Older articles reference the “TunTap” project, but AFAICT this software it is no longer recommended. Does anyone know of a good way to add networking to this setup without using TunTap? Best regards, Carl Winbäck

1 0

Requirements to enable discard support on virtio-blk
by Andrew Martin 30 Mar '22

30 Mar '22

Hello, I am attempting to enable discard support on the virtio-blk device on a QEMU VM however it isn't working. My understanding is that this is enabled in QEMU >= 4.0, so I am not sure why this isn't working: Host OS: Ubuntu 20.04 (kernel 5.4.0) Guest OS: Ubuntu 18.04 (kernel 4.15.0) Guest config: <os> <type arch='x86_64' machine='pc-q35-4.2'>hvm</type> </os> <disk type='file' device='disk'> <driver name='qemu' type='qcow2' discard='unmap'/> <source file='/var/lib/libvirt/images/myvm.qcow2' index='1'/> <backingStore/> <target dev='vda' bus='virtio'/> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/> </disk> What are the values for machine type that will support discard on virtio-blk? Anything 4.0 or greater (e.g. would pc-i440fx-4.0 work too)? I can see from the host's perspective that the guest appears to have discard enabled because the following command shows "discard = true": # virsh qemu-monitor-command myvm --hmp info qtree | grep discard yet inside the VM, even with the "discard" mount option set: # for f in /sys/block/vda/queue/discard_*; do echo $f; cat $f; done /sys/block/vda/queue/discard_granularity 0 /sys/block/vda/queue/discard_max_bytes 0 /sys/block/vda/queue/discard_max_hw_bytes 0 /sys/block/vda/queue/discard_zeroes_data 0 Are the virtio drivers in the guest kernel too old to support discard on virtio-blk? Or is something else missing? Thanks, Andrew

1 0

virDomainCoreDump output format
by Shelly Kagan 29 Mar '22

29 Mar '22

Hi all, I have a small question regarding virDomainCoreDump. In the documentation[1] it is stated that the output is of format RAW. After implementing a function using this command the output file format that I see is ELF. I understand those formats are different, so is the documentation not updated? Is there a reason I will get an ELF format instead of RAW? Appreciate your help! [1] https://libvirt.org/html/libvirt-libvirt-domain.html#virDomainCoreDumpWithF… -- Shelly Kagan Senior Software Engineer Red Hat <https://www.redhat.com> <https://www.redhat.com>

2 1

PHP Warning: libvirt_domain_new(): Cannot get installation XML
by Benjamin Smith 29 Mar '22

29 Mar '22

Despite great success at using php-libvirt with other functions, I have been entirely unsuccessful in getting it to create a new domain/machine. Any time I do, and with virtually anything I try, I get the above error message. Running PHP 7.4 (remi) on otherwise stock AlmaLinux. *[root@sb4 html]# cat /etc/redhat-release AlmaLinux release 8.5 (Arctic Sphynx* *[root@sb4 html]# rpm -qa php php-fpm php-libvirt nginxphp-7.4.28-1.el8.remi.x86_64nginx-1.14.1-9.module_el8.3.0+2165+af250afe.alma.x86_64php-fpm-7.4.28-1.el8.remi.x86_64php-libvirt-0.5.5-1.el8.remi.7.4.x86_6412 XEON E312xx cores, 24 w/HT, 192GB RAM, etc. * When I run it, I find in php-fpm www.error-log: *[24-Mar-2022 20:05:51 UTC] PHP Warning: libvirt_domain_new(): Cannot get installation XML in /var/www/html/manage.php on line 190* Matching message onscreen: *Warning: libvirt_domain_new(): Cannot get installation XML in /var/www/html/manage.php on line 191* Here's the offending code: $networks = [ *'mac'* => '52:54:00:06:a7:df', *'network'* => 'default', *'model'* => *'e1000'*, ]; $disks = [ *'path'* => *"/var/lib/libvirt/images/myvm.qcow2"*, *'driver'* => *'qcow2'*, *'bus'* => *'ide'*, *'dev'* => *'hda'*, *'size'* => *'40G'*, *'flags'* => null, ]; error_reporting(-1); $result = libvirt_domain_new( $conn, 'myvm',* // name of the new domain* null,* // optional architecture string, can be NULL to get default (or false)* 2048,* // number of megabytes of RAM to be allocated for domain* 8192,* // maximum number of megabytes of RAM to be allocated for domain* 2,* // number of VCPUs to be allocated to domain* *'/var/www/html/AlmaLinux-8.4-x86_64-dvd.iso'*,* // installation ISO image for*$ $disks,* // array of disk devices for domain* $networks, null ); I've tried various values for $disks and $networks, setting error reporting to -1 (display anything and everything), journalctl -f on both the webserver and the virt host, etc but was never able to see any error other than this one. I've also been looking in the source code file for anything obvious, and I've been utterly unsuccessful in changing the error message. For example, inserting an invalid path for the ISO image doesn't result in an error message that it *looks* like it should be throwing errors about invalid ISO image. In fact, I've even tried passing ALL NULL/EMPTY VALUES and with the exception of the $conn connection variable, I only get this "Cannot get installation XML" error message: $result = libvirt_domain_new( $conn, null, null, null, null, null, null, [], [] ); Shouldn't I at least be seeing a message like "Name is 'myvm', memMB is 2048, maxmemMB is 8192" ? https://github.com/php/pecl-virtualization-libvirt/blob/master/src/libvirt-…

2 1

How to make the libvirt VM installed under the regular user boot during the system bootup?
by Martin T 21 Mar '22

21 Mar '22

Hi. I installed a virtual machine under a regular user(in other words, not under root user) with virt-install and configured this VM to boot automatically: $ virsh dominfo vm Id: 1 Name: vm UUID: eef95dd6-5efe-4059-8dcc-3e35db12f55d OS Type: hvm State: running CPU(s): 4 CPU time: 253.7s Max memory: 4194304 KiB Used memory: 4194304 KiB Persistent: yes Autostart: enable Managed save: no Security model: none Security DOI: 0 $ ls -l /home/user/.config/libvirt/qemu/autostart/ total 0 lrwxrwxrwx 1 user user 47 Apr 30 16:59 vm.xml -> /home/user/.config/libvirt/qemu/vm.xml $ The vm indeed starts automatically, but only when the regular user has logged in. I would like libvirtd(started by the systemd) to execute this VM already during the system bootup when the regular user has not yet logged in. How to accomplish this? I also made a symlink under /etc/libvirt/qemu/autostart/, but this did not help. thanks, Martin

2 1

how to reliably shutdown domains ?
by Lentes, Bernd 09 Mar '22

09 Mar '22

Hey guys, i have a two-node cluster with around 20 domains. Cluster-Software is pacemaker and corosync, OS is SLES 12 SP5. The scripts for starting/stopping the domains use virsh. Is there a way to reliably shutdown the domains via virsh ? I'm testing around, but sometimes the domains stop, sometimes they don't, sometimes it takes very long so that the cluster times out and fence the respective node. I'm using "virsh shutdown domain --mode acpi,agent" for the windows domains (not reliable) and for the linux domains "virsh shutdown domain", also not reliable. What can i do ? Bernd -- Bernd Lentes System Administrator Institute for Metabolism and Cell Death (MCD) Building 25 - office 122 HelmholtzZentrum München bernd.lentes(a)helmholtz-muenchen.de phone: +49 89 3187 1241 fax: +49 89 3187 2294 http://www.helmholtz-muenchen.de/mcd Public key: 30 82 01 0a 02 82 01 01 00 b3 72 3e ce 2c 0a 6f 58 49 2c 92 23 c7 b9 c1 ff 6c 3a 53 be f7 9e e9 24 b7 49 fa 3c e8 de 28 85 2c d3 ed f7 70 03 3f 4d 82 fc cc 96 4f 18 27 1f df 25 b3 13 00 db 4b 1d ec 7f 1b cf f9 cd e8 5b 1f 11 b3 a7 48 f8 c8 37 ed 41 ff 18 9f d7 83 51 a9 bd 86 c2 32 b3 d6 2d 77 ff 32 83 92 67 9e ae ae 9c 99 ce 42 27 6f bf d8 c2 a1 54 fd 2b 6b 12 65 0e 8a 79 56 be 53 89 70 51 02 6a eb 76 b8 92 25 2d 88 aa 57 08 42 ef 57 fb fe 00 71 8e 90 ef b2 e3 22 f3 34 4f 7b f1 c4 b1 7c 2f 1d 6f bd c8 a6 a1 1f 25 f3 e4 4b 6a 23 d3 d2 fa 27 ae 97 80 a3 f0 5a c4 50 4a 45 e3 45 4d 82 9f 8b 87 90 d0 f9 92 2d a7 d2 67 53 e6 ae 1e 72 3e e9 e0 c9 d3 1c 23 e0 75 78 4a 45 60 94 f8 e3 03 0b 09 85 08 d0 6c f3 ff ce fa 50 25 d9 da 81 7b 2a dc 9e 28 8b 83 04 b4 0a 9f 37 b8 ac 58 f1 38 43 0e 72 af 02 03 01 00 01

3 2

Resize backing store
by Jeff Brown 08 Mar '22

08 Mar '22

Apologies in advance if this be a stupid question, as everything I've read seems to suggest it's impossible. Slowly running out of space on a 200GB root partition. Is it possible to create a snapshot - leaving the QCOW2 image 'quiescent' - resize it using 'qemu-img resize' - then pivot the snapshot back? (Then shutdown, attach the storage to another bootable OS, and run fdisk and resize2fs.) Everything I've read says to shutdown the VM; but besides the real possibility of the snapshot blockcommit being corrupted when pivoted into the newly resized backing store, I don't see why it shouldn't work. And save some significant downtime. Please can someone advise if this is actually possible, or if I'm wasting my time? Thanks! -- Jeff Brown Future Foundation Cell 074 101 5170 VoIP 087 550 1210 Fax: 086 532 3508

2 1

About RO connection
by Xingbo Kan 08 Mar '22

08 Mar '22

Dear developers and users: Is there any standard or convention of which kind of APIs&flags could be invoked by RO connection? If there is any, please tell me in detail, thanks a lot! Kind regards, xkan

2 2

Number of the max supported VFs are different
by Yalan Zhang 08 Mar '22

08 Mar '22

Hi there, I have an Intel X520 network card, and I find the max supported VFs are different. Please check below outputs: # lspci -vvv -s 04:00.0 04:00.0 Ethernet controller: Intel Corporation Ethernet 10G 2P X520 Adapter (rev 01) ... Capabilities: [160 v1] Single Root I/O Virtualization (SR-IOV) IOVCap: Migration-, Interrupt Message Number: 000 IOVCtl: Enable- Migration- Interrupt- MSE- ARIHierarchy+ IOVSta: Migration- ** Initial VFs: 64, Total VFs: 64**, Number of VFs: 0, Function Dependency Link: 00 VF offset: 128, stride: 2, Device ID: 10ed Supported Page Size: 00000553, System Page Size: 00000001 Region 0: Memory at 0000000094400000 (64-bit, prefetchable) Region 3: Memory at 0000000094500000 (64-bit, prefetchable) VF Migration: offset: 00000000, BIR: 0 Kernel driver in use: ixgbe Kernel modules: ixgbe # cat /sys/class/net/enp4s0f0/device/sriov_totalvfs 63 # echo 64 > /sys/class/net/enp4s0f0/device/sriov_numvfs -bash: echo: write error: Numerical result out of range # echo 63 > /sys/class/net/enp4s0f0/device/sriov_numvfs # cat /sys/class/net/enp4s0f0/device/sriov_numvfs 63 The lspci command says the Total VFs supported is 64, while in the file "sriov_totalvfs" says it's 63. And the sriov_numvfs file will take precedence. Why are the numbers different? Just a little curious. Thank you! ------- Best Regards, Yalan Zhang IRC: yalzhang

2 2