June 2020 - Users - libvirt List Archives

[libvirt-users] [virtual interface] detach interface during boot succeed with no changes
by Yalan Zhang 08 Sep '22

08 Sep '22

Hi guys, when I detach an interface from vm during boot (vm boot not finished), it always fail. I'm not sure if there is an existing bug. I have confirmed with someone that for disk, there is similar behavior, if this is also acceptable? # virsh destroy rhel7.2; virsh start rhel7.2 ;sleep 2; virsh detach-interface rhel7.2 network 52:54:00:98:c4:a0; sleep 2; virsh dumpxml rhel7.2 |grep /interface -B9 Domain rhel7.2 destroyed Domain rhel7.2 started Interface detached successfully <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/> </controller> <interface type='network'> <mac address='52:54:00:98:c4:a0'/> <source network='default' bridge='virbr0'/> <target dev='vnet0'/> <model type='rtl8139'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> When I detach after the vm boot, expand the sleep time to 10, it will succeed. # virsh destroy rhel7.2; virsh start rhel7.2 ;sleep 10; virsh detach-interface rhel7.2 network 52:54:00:98:c4:a0; sleep 2; virsh dumpxml rhel7.2 |grep /interface -B9 Domain rhel7.2 destroyed Domain rhel7.2 started Interface detached successfully ------- Best Regards, Yalan Zhang IRC: yalzhang Internal phone: 8389413

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Set hostname of guest during installation time
by john doe 05 Nov '20

05 Nov '20

Hi, I would like to set the hostname when installing a guest, with the below command the hostname is not set to 'try06' in the guest: virt-install --name=try06 --graphic none --pxe --network bridge=virbr0 How can I set the hostname of the guest during installation time? I realy appriciate the support I'm getting in here, I'm fairly new to libvirt. -- John Doe

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[libvirt-users] Live migrate + change interface name
by Marc Roos 08 Oct '20

08 Oct '20

Is it possible to do a live migrate of a guest, having on the from host a source_device=eth2 and to host a source_dev=eth1?

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[libvirt-users] Add Virtlyst to the list of libvirt users
by Daniel Nicoletti 24 Sep '20

24 Sep '20

Hi, I've just released v1.0.0 of Virtlyst[1] a web tool to manage VMs using Qt/C++/Cutelyst https://dantti.wordpress.com/2018/04/19/announcing-virtlyst-a-web-interface… Thanks. 1 - https://github.com/cutelyst/Virtlyst -- Daniel Nicoletti KDE Developer - http://dantti.wordpress.com

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guest-fsfreeze-freeze freezes all mounted block devices
by Marc Roos 10 Aug '20

10 Aug '20

I wondered if anyone here can confirm that virsh qemu-agent-command domain '{"execute":"guest-fsfreeze-freeze"}' Freezes all mounted block devices filesystems. So if I use 4 block devices they are all frozen for snapshotting. Or just the root fs?

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[libvirt-users] Question about disabling UFO on guest
by Bao Nguyen 05 Aug '20

05 Aug '20

Hello everyone, I would like to ask a question regarding to disable UFO of virtio vNIC in my guest. I have read the document at https://libvirt.org/formatdomain.html *host* The csum, gso, tso4, tso6, ecn and ufo attributes with possible values on and off can be used to turn off host offloading options. By default, the supported offloads are enabled by QEMU. *Since 1.2.9 (QEMU only)* The mrg_rxbuf attribute can be used to control mergeable rx buffers on the host side. Possible values are on (default) and off. *Since 1.2.13 (QEMU only)* *guest* The csum, tso4, tso6, ecn and ufo attributes with possible values on and off can be used to turn off guest offloading options. By default, the supported offloads are enabl ed by QEMU. *Since 1.2.9 (QEMU only)* Then I disabled UFO on my vNIC on guest as the following configuration <devices> <interface type='network'> <source network='default'/> <target dev='vnet1'/> <model type='virtio'/> <driver name='vhost' txmode='iothread' ioeventfd='on' event_idx='off' queues='5' rx_queue_size='256' tx_queue_size='256'> *<host gso='off' ufo='off' />* *<guest ufo='off'/>* </driver> </interface> </devices> Then I reboot my node to get the change effect and it works. However, can I disable the UFO without touching the host OS? or it always has to disable on both host and guest like that? Thanks, Brs, Natsu

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Could you please help with questions about the net failover feature
by Yalan Zhang 09 Jul '20

09 Jul '20

Hi laine, I have leave some questions on IRC, but my VPN broken time after time. Please ignore the questions on IRC. In my understanding, the standby and primary hostdev interface may be in different subnet. I'm not sure whether it is correct. Could you please help to explain? Thank you in advance. For example, primary hostdev is connected to vf-pool with <pf='eth0'/>, while the standby is connected to NAT network with " forward dev='eth0'". The standby interface will get ip as 192.168.122.x, but after NAT, it will be in the same subnet of the vf. So after the VF is unplugged, the packet will still broadcast in the same subnet, and the vm will get the packet as the standby share the same mac. Right? Thank you! ------- Best Regards, Yalan Zhang IRC: yalzhang

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image of OS X how to boot
by Jerry Geis 01 Jul '20

01 Jul '20

I have an image of OS X that I made with from the physical disk using dd. When I boot with libvirt-manager and environment I get an error. no bootable option or device was found. Using CentOS 8 host - I tried fdisk image.img and I no longer see any options there to toggle bootable partition option. How can I boot OSX ? Thanks, Jerry

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plug pre-created tap devices to libvirt guests
by Miguel Duarte de Mora Barroso 01 Jul '20

01 Jul '20

Hi all, I'm aware that it is possible to plug pre-created macvtap devices to libvirt guests - tracked in RFE [0]. My interpretation of the wording in [1] and [2] is that it is also possible to plug pre-created tap devices into libvirt guests - that would be a requirement to allow kubevirt to run with less capabilities in the pods that encapsulate the VMs. I took a look at the libvirt code ([3] & [4]), and, from my limited understanding, I got the impression that plugging existing interfaces via `managed='no' ` is only possible for macvtap interfaces. Would you be able to shed some light into this ? Is it possible on libvirt-5.6.0 to plug pre-created tap devices to libvirt guests ? [0] - https://bugzilla.redhat.com/show_bug.cgi?id=1723367 [1] - https://bugzilla.redhat.com/show_bug.cgi?id=1723367#c2 [2] - https://bugzilla.redhat.com/show_bug.cgi?id=1723367#c3 [3] - https://github.com/libvirt/libvirt/blob/master/src/qemu/qemu_interface.c#L4… [4] - https://github.com/libvirt/libvirt/blob/master/src/qemu/qemu_interface.c#L4…

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Do we need "amd_iommu=on" for AMD system anymore?
by Yalan Zhang 30 Jun '20

30 Jun '20

Hi, Since long time ago, to enable the SR-IOV VF pci passthrough function, I'm always adding "amd_iommu=on" into kernel cmdline on AMD system. But recently I found even I do not do this action, IOMMU is still enabled by kernel on AMD system. After searching, I found there is no such setting any more, refer to https://github.com/torvalds/linux/blob/master/Documentation/admin-guide/ker… There are only 3 possible value as below: amd_iommu= fullflush off force_isolation Could anyone can help to confirm the changes? Thank you! And another question, it is said that the "iommu=pt" option is to improves IO performance for devices in the host, it is not a must for VF PCI passthrough, right? I'm not sure about the user cases. [Reference] 1. Reference about adding "amd_iommu=on", and it may be outdated: http://dpdk-guide.gitlab.io/dpdk-guide/setup/iommu.html 2. On AMD system without adding "amd_iommu=on" in the kernel cmdline, the iommu is enabled: # cat /proc/cmdline BOOT_IMAGE=(hd0,msdos1)/vmlinuz-4.18.0-193.el8.x86_64 root=/dev/mapper/rhel_hp--dl385g10--16-root ro crashkernel=auto resume=/dev/mapper/rhel_hp--dl385g10--16-swap rd.lvm.lv=rhel_hp-dl385g10-16/root rd.lvm.lv=rhel_hp-dl385g10-16/swap console=ttyS0,115200n81 # dmesg | grep -i iommu [ 3.712029] iommu: Default domain type: Passthrough [ 6.736019] pci 0000:00:00.2: IOMMU performance counters supported ... [ 6.780040] pci 0000:e0:00.2: IOMMU performance counters supported [ 6.786740] pci 0000:00:01.0: Adding to iommu group 0 [ 6.791876] pci 0000:00:01.1: Adding to iommu group 1 [ 6.797015] pci 0000:00:01.2: Adding to iommu group 2 [ 6.802150] pci 0000:00:01.4: Adding to iommu group 3 ... [ 7.866463] pci 0000:e0:00.2: Found IOMMU cap 0x40 [ 7.920222] perf/amd_iommu: Detected AMD IOMMU #0 (2 banks, 4 counters/bank). [ 7.927428] perf/amd_iommu: Detected AMD IOMMU #1 (2 banks, 4 counters/bank) ... ------- Best Regards, Yalan Zhang IRC: yalzhang

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