December 2019 - Users - libvirt List Archives

[libvirt-users] Error in launching chasis
by abhishek jain 17 Dec '19

17 Dec '19

Hi I am new to Libvirt and is starting Chassis but getting following error qemu-system-x86_64:-netdev tap,id=net0,ifname=tap01,vhost=on,script=no,downscript=no: tap: open vhost char device failed:Operation not permitted What could be the reason RegardsAbhishek

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[libvirt-users] Change in treatment of qcow2 with chained backing files in v5.10.0?
by Jens John 17 Dec '19

17 Dec '19

Hello list, upon upgrading from libvirt v5.9.0 -> v5.10.0, libvirt started calling qemu differently causing the VM operating system to not be found. I'm wondering whether I'm chasing a bug, or have to otherwise fix my domain config (created by virt-manager). To start with, I have a Windows 7 domain based on the following images: windows7-base.qcow2: QEMU QCOW2 Image (v3), 53687091200 bytes windows7-Office2013.qcow2: QEMU QCOW2 Image (v3), has backing file (path windows7-taintable.qcow2), 80530636800 bytes windows7-taintable.qcow2: QEMU QCOW2 Image (v3), has backing file (path windows7-base.qcow2), 53687091200 bytes The VM must be launched with image windows7-Office2013.qcow2. Using the domain config [1] with a <disk> section <disk type='file' device='disk'> <driver name='qemu' type='qcow2'/> <source file='/home/joj/lib/vm/windows/windows7-Office2013.qcow2'/> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/> </disk> libvirt 5.9.0 is calling qemu 4.2.0 like [2], and libvirt 5.10.0 like [3], the differences being (5.9.0 1st, 5.10.0 2nd lines) [--drive file=/home/joj/lib/vm/windows/windows7-Office2013.qcow2,format=qcow2,if=none,id=drive-virtio-disk0-] {+-blockdev {"driver":"file","filename":"/home/joj/lib/vm/windows/windows7-taintable.qcow2","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"} -blockdev {"node-name":"libvirt-2-format","read-only":true,"driver":"raw","file":"libvirt-2-storage"} -blockdev {"driver":"file","filename":"/home/joj/lib/vm/windows/windows7-Office2013.qcow2","node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"} -blockdev {"node-name":"libvirt-1-format","read-only":false,"driver":"qcow2","file":"libvirt-1-storage","backing":"libvirt-2-format"}+} -device [-virtio-blk-pci,scsi=off,bus=pci.0,addr=0x7,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1-] {+virtio-blk-pci,scsi=off,bus=pci.0,addr=0x7,drive=libvirt-1-format,id=virtio-disk0,bootindex=1+} As you can see, 5.10.0 is expanding the backing file chain, not leaving that to qemu. Under 5.10.0, I get an Operating System not Found error, under 5.9.0, with the shorter -drive argument, everything works as desired. Can you perhaps advise me how I either fix the domain spec [1] to get libvirt to use a true equivalent to the old qemu invocation as I don't think this is a qemu problem, or how I can turn the new-style JSON parametrization off? Other suggestions how to tackle this would also be much appreciated. --- [1] https://0x0.st/z0KM.xml [2] https://0x0.st/z0K1.txt [3] https://0x0.st/z0Kj.txt

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[libvirt-users] Request to be allotted a project or a feature in pipeline
by Utsav Parmar 16 Dec '19

16 Dec '19

To whom it may concern, I'm Utsav Parmar, pursuing my B. Tech in Computer Engineering. I like to work on new technologies and am currently looking for open-source projects to contribute to. As it may turn out, I've got a college project in my curriculum this semester under “Software Development Practice”, and I'd like to work upon a project and/or a feature in pipeline spanning over 3 months in Libvirt organization as a part of the same college project. My mentor cum professor has already agreed for the same, given that I get approval from one of the maintainers. So, if possible, will you please allot me something to work upon? Thank you for your time. Looking forward to hearing from you. Regards, Utsav Parmar

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[libvirt-users] nvme, spdk and host linux version
by Mauricio Tavares 12 Dec '19

12 Dec '19

I have been following the patches on nvme support on the list and was wondering: If I wanted to build a vm host to be on the bleeding edge for nvme and spdk fun in libvirt, which linux distro -- fedora/ubuntu/centos/etc -- should I pick?

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[libvirt-users] What's the best way to make use of VLAN interfaces with VMs?
by Richard Achmatowicz 04 Dec '19

04 Dec '19

Hello I have a problem with attaching VMs to a VLAN interface. Here is my setup: I have several physical hosts connected by a physical switch. Each host has two NICs leading to the switch, which have been combined into a team, team0. Each host a has a bridge br1, which has team0 as a slave. So communication between hosts is based on the IP address of bridge br1 on each host. Up until recently, using libvirt and KVM, I was creating VMs which had one interface attached the default virtual network and one interface attached to the bridge: virt-install ... --network network=default --network bridge=br1 ... I would then statically assign an IP address to the bridge interface on the guest when installing the OS. A few days ago, a VLAN was introduced to split up the network. I created a new VLAN interface br1.600 on each of the hosts. My initial attempt was to do try this: virt-install ... --network network=default --network bridge=br1.600 ... which did not work. It then dawned on me that a VLAN interface and a bridge aren't treated the same. So I started to look for ways to allow my VMs to bind to this new interface. This would seem to be a common situation. What is the best way to work around this? Both the host bridge and the host VLAN interface already have their assigned IP addresses and appear like this in libvirt: [root@clusterdev01 ]# ifconfig br1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.0.110 netmask 255.255.255.0 broadcast 192.168.0.255 inet6 fe80::1e98:ecff:fe1b:276d prefixlen 64 scopeid 0x20<link> ether 1c:98:ec:1b:27:6d txqueuelen 1000 (Ethernet) RX packets 833772 bytes 2976958254 (2.7 GiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 331237 bytes 23335124 (22.2 MiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 br1.600: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.1.110 netmask 255.255.255.0 broadcast 192.168.1.255 inet6 fe80::1e98:ecff:fe1b:276d prefixlen 64 scopeid 0x20<link> ether 1c:98:ec:1b:27:6d txqueuelen 1000 (Ethernet) RX packets 189315 bytes 9465744 (9.0 MiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 302 bytes 30522 (29.8 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 [root@clusterdev01]# virsh iface-list --all Name State MAC Address --------------------------------------------------- br1 active 1c:98:ec:1b:27:6d br1.600 active 1c:98:ec:1b:27:6d [root@clusterdev01 sysadmin]# virsh iface-dumpxml br1.600 <interface type='vlan' name='br1.600'> <protocol family='ipv4'> <ip address='192.168.1.110' prefix='24'/> </protocol> <protocol family='ipv6'> <ip address='fe80::1e98:ecff:fe1b:276d' prefix='64'/> </protocol> <link state='up'/> <vlan tag='600'> <interface name='br1'/> </vlan> </interface> I tried following some suggestions which wrapped the vlan interface in a bridge interface, but in ended up trashing the br1.600 interface which was originally defined on the host. Is there a failsafe way to deal with such a situation? Am I doing something completely wrong here? In would like br1.600 to behave like br1 ..... Any suggestions or advice greatly appreciated. Richard

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[libvirt-users] Converting LVM to qcow2
by ort_libvirt＠bergersen.no 03 Dec '19

03 Dec '19

Hi! I need to convert a KVM virtual machine from LVM to a qcow2 image, and wonder if this is the best way to do it (*1): [$] qemu-img convert -O qcow2 /dev/vg_name/lv_name/ /var/lib/libvirt/images/image_name.qcow2 If this is the best way to do this, will this keep the information on: /dev/vg_name/lv_name/ untouched? Thanks, and please point me towards another mailing list if this it not right place to ask questions related to qemu-img! Best regards, Richard Taubo *1) Via: http://nocoast-tech.blogspot.com/2010/05/converting-kvm-guests-from-lvm-to-…

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[libvirt-users] Domain XML Multicast Tunnel
by Richard M 03 Dec '19

03 Dec '19

Hello I found under networking in the Domain XML 'Multcast tunnel'. My question is does anyone know what is the intended use of multicast tunnel networking?What are the potential pitfalls of using such a configuration other than what's highlighted in the domain xml. eg: can it suffer from throughput issues? Can the tunnel be accessed from outside Libvirt? I'm struggling to find any information about it. If anyone has any information about it, Or where I can obtain such information it would be appreciated. Regards Richard

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