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Need help
by Gk Gk 02 Dec '22

02 Dec '22

Hi, We have an openstack platform and we are trying to get the network details of the guest vm on the hypervisors using the python libvirt library (domain.interfaceStats) . But in cases of SR-IOV vms, the interface is not being reported by the above tool. The interface in this case is "hostdev" in the guest xml definition. Can anyone let me know how to find out the sr-iov network interface details of the guest vm ? Thanks Kumar

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detach-interface success but domiflist still saw interface
by Jiatong Shen 29 Nov '22

29 Nov '22

Hello Commnunity, I saw an weird situation on a phytium machine (arm64 v8), after the following commands, I can still see the interface which should be successfully detached. virsh # detach-interface 4a365b06-2597-4c17-8b44-dbb6953f9ced bridge --mac fa:16:3e:c5:62:40 Interface detached successfully Future qmp commands shows, that a device hostnet23 exists but seems no front end device exists. So what could be the problem? Thank you very much. /# virsh domiflist --inactive 4a365b06-2597-4c17-8b44-dbb6953f9ced Interface Type Source Model MAC ------------------------------------------------------------------------ tap1eca5838-d5 bridge qbr1eca5838-d5 virtio fa:16:3e:9b:1c:fd tap20318b8b-b5 bridge qbr20318b8b-b5 virtio fa:16:3e:e1:bc:58 tap43bab93f-9a bridge qbr43bab93f-9a virtio fa:16:3e:8f:1e:23 tap2b059179-d9 bridge qbr2b059179-d9 virtio fa:16:3e:4e:f9:47 tap1ec7cd98-1d bridge qbr1ec7cd98-1d virtio fa:16:3e:21:5b:e0 tap46c2470d-08 bridge qbr46c2470d-08 virtio fa:16:3e:33:68:19 tap0a402f8f-05 bridge qbr0a402f8f-05 virtio fa:16:3e:89:dd:c4 tap4e737f62-e2 bridge qbr4e737f62-e2 virtio fa:16:3e:1d:2a:1c tap024ec465-22 bridge qbr024ec465-22 virtio fa:16:3e:16:1c:df tapd17d320e-a5 bridge qbrd17d320e-a5 virtio fa:16:3e:08:bf:9f tapcef35fc7-40 bridge qbrcef35fc7-40 virtio fa:16:3e:d6:5b:bf tap83de3d8e-b5 bridge qbr83de3d8e-b5 virtio fa:16:3e:69:21:90 tap660a3bb9-17 bridge qbr660a3bb9-17 virtio fa:16:3e:b7:33:d3 tap35d08903-93 bridge qbr35d08903-93 virtio fa:16:3e:15:ce:a3 tap8e63ed74-2a bridge qbr8e63ed74-2a virtio fa:16:3e:0a:3f:a8 tapb61b097d-e8 bridge qbrb61b097d-e8 virtio fa:16:3e:f0:f9:da tap189d75de-ee bridge qbr189d75de-ee virtio fa:16:3e:be:98:9d tap7108158a-fe bridge qbr7108158a-fe virtio fa:16:3e:a2:8b:e8 tap38015662-f2 bridge qbr38015662-f2 virtio fa:16:3e:d2:45:fe tapcc37cd83-fc bridge qbrcc37cd83-fc virtio fa:16:3e:64:26:f8 tapaf3ccc2a-0c bridge qbraf3ccc2a-0c virtio fa:16:3e:d2:0a:99 # virsh domiflist 4a365b06-2597-4c17-8b44-dbb6953f9ced Interface Type Source Model MAC ------------------------------------------------------------------------ tap1eca5838-d5 bridge qbr1eca5838-d5 virtio fa:16:3e:9b:1c:fd tap20318b8b-b5 bridge qbr20318b8b-b5 virtio fa:16:3e:e1:bc:58 tap43bab93f-9a bridge qbr43bab93f-9a virtio fa:16:3e:8f:1e:23 tap2b059179-d9 bridge qbr2b059179-d9 virtio fa:16:3e:4e:f9:47 tap1ec7cd98-1d bridge qbr1ec7cd98-1d virtio fa:16:3e:21:5b:e0 tap46c2470d-08 bridge qbr46c2470d-08 virtio fa:16:3e:33:68:19 tap0a402f8f-05 bridge qbr0a402f8f-05 virtio fa:16:3e:89:dd:c4 tap4e737f62-e2 bridge qbr4e737f62-e2 virtio fa:16:3e:1d:2a:1c tap024ec465-22 bridge qbr024ec465-22 virtio fa:16:3e:16:1c:df tapd17d320e-a5 bridge qbrd17d320e-a5 virtio fa:16:3e:08:bf:9f tapcef35fc7-40 bridge qbrcef35fc7-40 virtio fa:16:3e:d6:5b:bf tap7ceb7a77-4d bridge qbr7ceb7a77-4d virtio fa:16:3e:c5:62:40 tap83de3d8e-b5 bridge qbr83de3d8e-b5 virtio fa:16:3e:69:21:90 tap660a3bb9-17 bridge qbr660a3bb9-17 virtio fa:16:3e:b7:33:d3 tap35d08903-93 bridge qbr35d08903-93 virtio fa:16:3e:15:ce:a3 tap8e63ed74-2a bridge qbr8e63ed74-2a virtio fa:16:3e:0a:3f:a8 tapb61b097d-e8 bridge qbrb61b097d-e8 virtio fa:16:3e:f0:f9:da tap189d75de-ee bridge qbr189d75de-ee virtio fa:16:3e:be:98:9d tap7108158a-fe bridge qbr7108158a-fe virtio fa:16:3e:a2:8b:e8 tap38015662-f2 bridge qbr38015662-f2 virtio fa:16:3e:d2:45:fe tapcc37cd83-fc bridge qbrcc37cd83-fc virtio fa:16:3e:64:26:f8 tapaf3ccc2a-0c bridge qbraf3ccc2a-0c virtio fa:16:3e:d2:0a:99 virsh # qemu-monitor-command --hmp 4a365b06-2597-4c17-8b44-dbb6953f9ced info network net0: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:9b:1c:fd \ hostnet0: index=0,type=tap,fd=40 net1: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:e1:bc:58 \ hostnet1: index=0,type=tap,fd=42 net5: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:8f:1e:23 \ hostnet5: index=0,type=tap,fd=52 net9: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:4e:f9:47 \ hostnet9: index=0,type=tap,fd=58 net15: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:21:5b:e0 \ hostnet15: index=0,type=tap,fd=262 net16: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:33:68:19 \ hostnet16: index=0,type=tap,fd=94 net17: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:89:dd:c4 \ hostnet17: index=0,type=tap,fd=108 net18: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:1d:2a:1c \ hostnet18: index=0,type=tap,fd=218 net19: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:16:1c:df \ hostnet19: index=0,type=tap,fd=226 net20: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:08:bf:9f \ hostnet20: index=0,type=tap,fd=234 net21: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:d6:5b:bf \ hostnet21: index=0,type=tap,fd=242 hostnet23: index=0,type=tap,fd=273 net25: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:69:21:90 \ hostnet25: index=0,type=tap,fd=289 net26: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:b7:33:d3 \ hostnet26: index=0,type=tap,fd=44 net27: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:15:ce:a3 \ hostnet27: index=0,type=tap,fd=73 net28: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:0a:3f:a8 \ hostnet28: index=0,type=tap,fd=102 net29: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:f0:f9:da \ hostnet29: index=0,type=tap,fd=185 net30: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:be:98:9d \ hostnet30: index=0,type=tap,fd=201 net31: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:a2:8b:e8 \ hostnet31: index=0,type=tap,fd=255 net32: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:d2:45:fe \ hostnet32: index=0,type=tap,fd=279 net33: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:64:26:f8 \ hostnet33: index=0,type=tap,fd=287 net34: index=0,type=nic,model=virtio-net-pci,macaddr=fa:16:3e:d2:0a:99 \ hostnet34: index=0,type=tap,fd=303 -- Best Regards, Jiatong Shen

2 3

IO while taking a disks-only snapshot
by Or Ozeri 21 Nov '22

21 Nov '22

Hi, Assume I'm running a VM with the qemu driver in libvirt, with multiple disks, with no guest agent. Now if I take a disks-only snapshot of that active VM. I see that under the hood, libvirt is issuing a qmp transaction with blockdev-snapshot command per each disk. I also see that qmp_transaction in qemu is draining all disks IO before performing the transaction (calling bdrv_drain_all). But once the transaction has started, is it possible that any incoming guest disk IO will be processed before the transaction completes? Assuming that's not possible, how is this "block disk IO while running the transaction" is enforced? Is it the call to GLOBAL_STATE_CODE() at the beginning of qemu's qmp_transaction(...)? Thanks, Or I

1 0

redirect console to file and restore user owner on domain destroy
by Darragh Bailey 21 Nov '22

21 Nov '22

Hi, I'm generating some domain XML to have the serial console output sent to a file for subsequent debug after the domain is no longer running. I'm noticing that the file ends up being owned by root with permissions of 600. I expected that it would need to be owned by root when the VM was running using the qemu:///system uri for security purposes, however I had hoped there would be a way to reset the owner and group back to the original values on destroy. Is this possible? I had hoped there might be something similar to what is possible with the permissions element for storage pools. Started experimenting adding seclabel child elements to the serial element, but it seems to only affect ownership while the domain is running and when it is destroyed it still ends up being owned as root. creating the domain with the following serial/console elements: <serial type='file'> <source path='/home/testuser/vagrant-libvirt/logfiles/test.log'> <seclabel type='dynamic' model='dac' relabel='yes'> <label>+1002:+1002</label> </seclabel> </source> <target port='0'/> </serial> <console type='file'> <source path='/home/testuser/vagrant-libvirt/logfiles/test.log'/> <target type='serial' port='0'/> </console> I've tried experimenting with a couple of different values but to no success. It appears to only change the user group the file is set to while the domain is running, and sets it to root when the VM is destroyed, instead of returning it to the original user. Is there any way with libvirt to have the file owned by the user after the VM is destroyed (doesn't matter if it's owned by root at runtime), when connecting using qemu:///system? -- Darragh Bailey

1 1

Libvirt slow after a couple of months uptime
by André Malm 21 Nov '22

21 Nov '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

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CPU frequency in virsh capabilites differs from lscpu
by Mevludin Blazevic 17 Nov '22

17 Nov '22

Hi all, typing virsh capabilities on my one of my server results in the following output: <host> <uuid>5a692c00-7544-11eb-8000-ac1f6b365280</uuid> <cpu> <arch>x86_64</arch> <model>EPYC-Rome</model> <vendor>AMD</vendor> <microcode version='137367637'/> <counter name='tsc' frequency='2799999000'> lscpu however shows "CPU max MHz" as 2800.0000 on all servers. On my other machines, virsh capabilites shows the max frequency as follows: <vendor>AMD</vendor> <microcode version='137367629'/> <counter name='tsc' frequency='2800000000'/> libvirt and qemu version are btw identical. I assume that the CPU clock speed may differ or is it a libvirt configuration that I need to adjust? Regards, Mevludin

1 0

blockcopy preserve original cache mode value
by Jiatong Shen 16 Nov '22

16 Nov '22

Hello Community, We are observing that after a blockcopy, the disk backend will inherit from original disk's cache mode configuration even though a new cache mode is given. Specifically, the function https://github.com/libvirt/libvirt/blob/cd94d891fb4b5cdda229f58b1dee261d551… which eventually calls qemuDomainPrepareDiskSourceData and override input config. My question is is this on purpose? Because seems like qemu allows different configs. Thnak you very much for the help. -- Best Regards, Jiatong Shen

2 2

domain_qemu_agent_command($domain,$cmd,$timeout,$flags)
by Simon Fairweather 16 Nov '22

16 Nov '22

Should there be a way to suppress errors using the flags? error : qemuDomainAgentAvailable:8411 : Guest agent is not responding: QEMU guest agent is not connected Or is there a libvirt function to check connection status or another way?

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[FOSDEM][CFP] Virtualization & IaaS Devroom
by Piotr Kliczewski 10 Nov '22

10 Nov '22

We are excited to announce that the call for proposals is now open for the Virtualization & IaaS devroom at the upcoming FOSDEM 2023, to be hosted on February 4th 2023. 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 would like to invite all those who are involved in these fields to submit your proposals by December 10th, 2022. 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: 10th December 2022 Acceptance notifications: 15th December 2022 Final schedule announcement: 20th December 2022 Devroom: First half of 4th February 2023 Submit Your Proposal All submissions must be made via the Pentabarf event planning site[1]. If you have not used Pentabarf before, you will need to create an account. If you submitted proposals for FOSDEM in previous years, you can use your existing account. After creating the account, select Create Event to start the submission process. Make sure to select Virtualization and IaaS devroom from the Track list. Please fill out all the required fields, and 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.) Submission Guidelines Mentored presentations will have 25-minute slots, where 20 minutes will include the presentation and 5 minutes will be reserved for questions. The number of newcomer session slots is limited, so we will probably not be able to accept all applications. You must submit your talk and abstract to apply for the mentoring program, our mentors are volunteering their time and will happily provide feedback but won't write your presentation for you! If you are experiencing problems with Pentabarf, the proposal submission interface, or have other questions, you can email our devroom mailing list[2] and we will try to help you. How to Apply In addition to agreeing to video recording and confirming that you can attend FOSDEM in case your session is accepted, please write "speaker mentoring program application" in the "Submission notes" field, and list any prior speaking experience or other relevant information for your application. Code of Conduct Following the release of the updated code of conduct for FOSDEM, 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. Call for Volunteers We are also looking for volunteers to help run the devroom. We need assistance watching time for the speakers, and helping with video for the devroom. Please contact devroom mailing list [2] for more information. 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://penta.fosdem.org/submission/FOSDEM17> https://penta.fosdem.org/submission/FOSDEM23 [2] iaas-virt-devroom at lists.fosdem.org

1 0

Serial traffic hoses virtual machine interactive performance?
by Lars Kellogg-Stedman 09 Nov '22

09 Nov '22

I have a pair of virtual machines connected via a serial link. Machine `node0.virt` is configured like this: <serial type="unix"> <source mode="bind" path="/tmp/serial0"/> <target type="isa-serial" port="1"> <model name="isa-serial"/> </target> <alias name="serial1"/> </serial> And machine `node1.virt` is configured like this: <serial type="unix"> <source mode="connect" path="/tmp/serial0"/> <target type="isa-serial" port="1"> <model name="isa-serial"/> </target> <alias name="serial1"/> </serial> If I have any sort of file transfer running over the serial link (e.g., a zmodem file transfer over raw serial, or an `scp` over a SLIP or PPP connection), the interactive performance of the *receiving* machine (accessed via the console or over a network connection) tanks -- it becomes almost unusable until the file transfer completes (or is cancelled). What's going on there, and is there a way to improve the performance? (Same behavior when connected using a pty device instead of a unix socket.) -- Lars Kellogg-Stedman <lars(a)redhat.com> | larsks @ {irc,twitter,github} http://blog.oddbit.com/ | N1LKS

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