January 2018 - Users - libvirt List Archives

[libvirt-users] bridge / ubuntu / no arp reply
by François Chenais 15 Oct '26

15 Oct '26

Hello I'm trying to setup a bridged guest on an ubuntu 13.10 but it doesn't work. (Everything is ok with NAT) Network sniffing shows that arp replies don't come back to the guest. Test 1 ------ Guest : ping host_bridge_ip (ok) Test 2 ------ Guest: ping other_lan_host (KO) other_lan_host - receives arp who-is request - sends arp reply - arp -a shows the guest macaddr => Guest doesn't receive reply Test 3 ------ other_lan_host ping the Guest (KO) - arp -a shows "incomplete" addr - Guest receives nothing On Host ------- network tcpdump on bridge or vnet interfaces shows request but no reply ... Thanks in advance for help or ideas François

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[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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[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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[libvirt-users] ceph rbd pool and libvirt manageability (virt-install)
by Jelle de Jong 28 Aug '18

28 Aug '18

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello everybody, I created a rbd pool and activated it, but I can't seem to create volumes in it with virsh or virt-install? # virsh pool-dumpxml myrbdpool <pool type='rbd'> <name>myrbdpool</name> <uuid>2d786f7a-2df3-4d79-ae60-1535bcf1c6b5</uuid> <capacity unit='bytes'>6997998301184</capacity> <allocation unit='bytes'>10309227031</allocation> <available unit='bytes'>6977204658176</available> <source> <host name='ceph01.powercraft.nl' port='6789'/> <host name='ceph02.powercraft.nl' port='6789'/> <host name='ceph03.powercraft.nl' port='6789'/> <name>libvirt-pool</name> <auth type='ceph' username='libvirt'> <secret uuid='029a334e-ed57-4293-bb99-ffafa8867122'/> </auth> </source> </pool> # virt-install --version 1.0.1 # virsh --version 1.2.9 I ended using virsh edit ceph-test.powercraft.nl and making creating the disk manually. <disk type='network' device='disk'> <auth username='libvirt'> <secret type='ceph' uuid='029a334e-ed57-4293-bb99-ffafa8867122'/> </auth> <source protocol='rbd' name='libvirt-pool/kvm01-storage'> <host name='ceph01.powercraft.nl' port='6789'/> <host name='ceph02.powercraft.nl' port='6789'/> <host name='ceph03.powercraft.nl' port='6789'/> </source> <target dev='vdc' bus='virtio'/> </disk> I use virt-install a lot to define, import and undefine domains, how can I use virt-install to manage my rdb disks? Kind regards, Jelle de Jong -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iJwEAQECAAYFAlV1xlQACgkQ1WclBW9j5HkbPQP+PjNrzvlqysslOp2Yk7wH4Mxy 2sh2dn96G0KOAHEeEn3BN6IWlnD1TADZbHdpTtMwkdv48Xwn0sP1s+3QDM4pb3gP n+z+dVxS8FouDIy/eiso3IBCj3g4TWbEX8ZHqs3jKqe0lZgAXBzB9xYSUowcEBrZ ddkPbr8p8ozWyOG+9V8= =lkK7 -----END PGP SIGNATURE-----

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[libvirt-users] virRandomBits - not very random
by Brian Rak 01 Jun '18

01 Jun '18

I just ran into an issue where I had about 30 guests get duplicate mac addresses assigned. These were scattered across 30 different machines. Some debugging revealed that: 1) All the host machines were restarted within a couple seconds of each other 2) All the host machines had fairly similar libvirtd pids (within ~100 PIDs of each other) 3) Libvirt seeds the RNG using 'time(NULL) ^ getpid()' This perfectly explains why I saw so many duplicate mac addresses. Why is the RNG seed such a predictable value? Surely there has to be a better source of a random seed then the timestamp and the pid? The PID seems to me to be a very bad source of any randomness. I just ran a test across 60 of our hosts. 43 of them shared their PID with at least one other machine.

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[libvirt-users] Create qcow2 v3 volumes via libvirt
by Gionatan Danti 24 May '18

24 May '18

Hi all, on a fully patched CentOS 7.4 x86-64, I see the following behavior: - when creating a new volumes using vol-create-as, the resulting file is a qcow2 version 2 (compat=0.10) file. Example: [root@gdanti-lenovo vmimages]# virsh vol-create-as default zzz.qcow2 8589934592 --format=qcow2 --backing-vol /mnt/vmimages/centos6.img Vol zzz.qcow2 created [root@gdanti-lenovo vmimages]# file zzz.qcow2 zzz.qcow2: QEMU QCOW Image (v2), has backing file (path /mnt/vmimages/centos6.img), 8589934592 bytes [root@gdanti-lenovo vmimages]# qemu-img info zzz.qcow2 image: zzz.qcow2 file format: qcow2 virtual size: 8.0G (8589934592 bytes) disk size: 196K cluster_size: 65536 backing file: /mnt/vmimages/centos6.img backing file format: raw Format specific information: compat: 0.10 refcount bits: 16 - when creating a snapshot, the resulting file is a qcow2 version 3 (comapt=1.1) file. Example: [root@gdanti-lenovo vmimages]# virsh snapshot-create-as centos6left --disk-only --no-metadata snap.qcow2 Domain snapshot snap.qcow2 created [root@gdanti-lenovo vmimages]# file centos6left.snap.qcow2 centos6left.snap.qcow2: QEMU QCOW Image (v3), has backing file (path /mnt/vmimages/centos6left.qcow2), 8589934592 bytes [root@gdanti-lenovo vmimages]# qemu-img info centos6left.snap.qcow2 image: centos6left.snap.qcow2 file format: qcow2 virtual size: 8.0G (8589934592 bytes) disk size: 196K cluster_size: 65536 backing file: /mnt/vmimages/centos6left.qcow2 backing file format: qcow2 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false From what I know, this is a deliberate decision: compat=1.1 requires relatively recent qemu version, and creating a new volume play on the "safe side" of compatibility. It is possible to create a new volume using qcow2 version 3 (compat=1.1) format *using libvirt/virsh* (I know I can do that via qemu-img)? Any drawback on using version 3 format? 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

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[libvirt-users] kvm/libvirt on CentOS7 w/Windows 10 Pro guest
by Benjammin2068 14 Feb '18

14 Feb '18

Hey all, New to list, so I apologize if this has been asked a bunch already... Is there something I'm missing with Windows 10 as a guest that keeps Windows Updates from nuking the boot process? I just did an orderly shutdown and windows updated itself <I forgot to disable in time> only to reboot to the diagnostics screen which couldn't repair. going to command prompt and doing the usual "bootrec /fixmbr, /fixboot and /RebuildBcd" didn't help. This has happened a few times. I can't believe how fragile Win10pro is while running in a VM. (and it's happened on a couple machines I've been experimenting with -- both running same OS, but different hardware.) I just saw the FAQ about the libvirt repo for the virtio drivers for windows.... I need to go read more on it... but in the meantime, is there any other smoking gun I'm not aware of? (after lots of google searching) Thanks, -Ben

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[libvirt-users] libvirt and NAT on a system that already has a DHCP server
by john＠bluemarble.net 08 Feb '18

08 Feb '18

I'm trying to use virt-manager and qemu/kvm on Arch Linux. The box I'm using is also the router for my house. It runs a kea DHCP server. When I try to start the default NAT network, it can't start dnsmasq because that port is already bound. Is there a way to have it not bind on this interface? I see there is an except-on statement in the dnsmasq.conf, but I can't add lines to that directly, and I didn't see any way to add special options using virsh net-edit default. Thanks.

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[libvirt-users] is it possible to add <metadata/> to libvirt Network XML
by Shashwat shagun 01 Feb '18

01 Feb '18

i need to know is it possible to add metadata to Libvirt Network XML like i do in Domain XML with </metadata> tag? -- Regards, Shashwat Shagun

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[libvirt-users] Live update network configuration
by Shashwat shagun 01 Feb '18

01 Feb '18

Hi, i want live update the <metadata/> in libvirt network xml config. is this possible? -- Regards, Shashwat Shagun

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