November 2015 - 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] 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] Libvirt bite sized tasks
by Michal Privoznik 20 Mar '16

20 Mar '16

Dear lists, I've just started new wiki page which aim is to summarize small and trivial tasks, that starting contributors can take, investigate and implement. The aim is to give them something easy to start with while not scaring them out about complexity of our code. The page can be found here: http://wiki.libvirt.org/page/BiteSizedTasks The name is copied from qemu wiki: http://wiki.qemu.org/BiteSizedTasks Please, feel free to extend the list. I plan to use it in the future when interviewing GSoC candidates. Michal

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[libvirt-users] unable to dissect libvirt rpc packets using wireshark plugin
by gowrishankar 20 Jan '16

20 Jan '16

Hi, I am trying libvirt plugin in wireshark to dissect RPC payload in TCP, but finding dissector code not really working. My env is Fedora core 21 (x86_64) and installed packages are as follow: wireshark-1.12.6-1.fc21.x86_64 libvirt-wireshark-1.2.9.3-2.fc21.x86_64 Earlier, just after installation, I noticed libvirt.so available only in /usr/lib64/wireshark/plugins/1.12.5/ . Wireshark could not load libvirt plugin. So, I copied above .so into 1.12.6/ under same plugins folder, following it wireshark could list libvirt as supported protocol. tshark -G protocols | grep libvirt Libvirt libvirt libvirt However, on checking with some pcaps which has libvirt RPC calls captured on wire, wireshark does not list libvirt RPC packets, as I search for "libvirt" protocol in pcap. Have anyone experienced this before or if you have any pointer that I could check in my env, that would be very helpful. -- Regards, Gowrishankar M

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[libvirt-users] Questions about qcow2 file size management
by Jérôme 16 Dec '15

16 Dec '15

Hi all. I have a few questions regarding the qcow2 format. 1/ Allocated size vs. file size When creating a VM, I indicated a size of 10 G. $ls -lsh 7,7G -rw------- 1 libvirt-qemu libvirt-qemu 11G oct. 14 10:04 prod.qcow2 The allocated size is lesser than max size. Alright. I think I more or less grab the difference between allocated size and file size, but I'm not sure I get the point of the auto-grow feature of qcow2. Can someone confirm that if I have, say, a 60Go partition, I can create more than six 10Go VM, as long as each don't actually use the full 10 Go? Sort of like flying companies selling more tickets than seats in the plane assuming a few people won't come. In other words, can I have this on a 60Go drive? total 53G 7,4G -rw------- 1 root root 11G oct. 8 06:34 prod_151008.qcow2 7,4G -rw------- 1 root root 11G oct. 9 06:37 prod_151009.qcow2 7,5G -rw------- 1 root root 11G oct. 10 06:41 prod_151010.qcow2 7,5G -rw------- 2 root root 11G oct. 11 06:49 prod_151011.qcow2 7,5G -rw------- 1 root root 11G oct. 12 06:44 prod_151012.qcow2 7,5G -rw------- 1 root root 11G oct. 13 06:27 prod_151013.qcow2 7,7G -rw------- 1 root root 11G oct. 14 06:55 prod_151014.qcow2 (Total allocated is 53 < 60 but sum of 11G sizes is 77 G.) If so, then I guess I get the point. 2/ Backup size Is there a simple way to do backups that only take the actual allocated space (7,7 G in my example) instead of the max (10 G)? I'm using snapshots and blockcommits to backup a VM, thanks to help on this list. The scripts are on GitHub for anyone interested [1]. Basically, what the script does is snapshot then cp as local backup file. Then rsync to another backup partition. Both source and destination partitions are ext4. Source dir (where I cp the snapshots): # ls -lsh vmbackup/daily/ total 53G 7,4G -rw------- 1 root root 11G oct. 8 06:34 prod_151008.qcow2 7,4G -rw------- 1 root root 11G oct. 9 06:37 prod_151009.qcow2 7,5G -rw------- 1 root root 11G oct. 10 06:41 prod_151010.qcow2 7,5G -rw------- 2 root root 11G oct. 11 06:49 prod_151011.qcow2 7,5G -rw------- 1 root root 11G oct. 12 06:44 prod_151012.qcow2 7,5G -rw------- 1 root root 11G oct. 13 06:27 prod_151013.qcow2 7,7G -rw------- 1 root root 11G oct. 14 06:55 prod_151014.qcow2 Destination (where rsync copies the files): # ls -lsh /mnt/usb_hd/vm/vmbackup/daily/ total 71G 11G -rw------- 1 root root 11G oct. 8 06:34 prod_151008.qcow2 11G -rw------- 1 root root 11G oct. 9 06:37 prod_151009.qcow2 11G -rw------- 1 root root 11G oct. 10 06:41 prod_151010.qcow2 11G -rw------- 2 root root 11G oct. 11 06:49 prod_151011.qcow2 11G -rw------- 1 root root 11G oct. 12 06:44 prod_151012.qcow2 11G -rw------- 1 root root 11G oct. 13 06:27 prod_151013.qcow2 11G -rw------- 1 root root 11G oct. 14 06:55 prod_151014.qcow2 Allocated size is as big as file size. This kind of beats the point of having qcow2 grow as needed. Ideally, I would like to create VM with a huge max file size, but only backup the actually used space. How may I achieve this? I just tested qemu-img convert -O qcow2 prod_151008.qcow2 prod_151008_resize.qcow2 and I get 7,2G -rw-r--r-- 1 root root 7,2G oct. 14 10:51 prod_151008_resize.qcow2 Seems to work. I could do this before rsyncing. Is this the recommanded way? Is there a higher level libvirt command to use instead of qemu-img? 3/ Playing with allocated space My VM apparently has an allocated size of 7.7 G 7,7G -rw------- 1 libvirt-qemu libvirt-qemu 11G oct. 14 10:04 prod.qcow2 However, loging into it shows much less than 7.7 G is used: $df -h Filesystem Size Used Avail Use% Mounted on /dev/vda1 9.8G 2.0G 7.3G 22% / udev 10M 0 10M 0% /dev tmpfs 2.0G 17M 2.0G 1% /run tmpfs 4.9G 4.0K 4.9G 1% /dev/shm tmpfs 5.0M 0 5.0M 0% /run/lock tmpfs 4.9G 0 4.9G 0% /sys/fs/cgroup tmpfs 1003M 0 1003M 0% /run/user/1000 I understand once qcow2 has grown to a given allocated size, it won't de-allocate space automatically (auto-allocation is one way only). Perhaps I ended up loading 7Go of files, then those were deleted and now only 2Go are used but the file still has 7G allocated. Could be, but I don't see when this might have happened. Could there be another explanation? Say I want to minimize allocated space because it is a pity to use 2 Go and keep 7 Go backups (I know disk space is cheap, this is just an example), how may I shrink allocated space to currently used space? I'm not talking about shrinking the file, just minimizing the allocated size to keep small backups as per former paragraph, still keeping max file size big to let the VM grow further when needed. In other words, I'm aiming at 2,7G -rw------- 1 libvirt-qemu libvirt-qemu 11G oct. 14 10:04 prod.qcow2 not at 2,7G -rw------- 1 libvirt-qemu libvirt-qemu 2,7G oct. 14 10:04 prod.qcow2 The guest is a Linux, BTW. 4/ Playing with qcow2 file sizes Say I've got this file 7,7G -rw------- 1 libvirt-qemu libvirt-qemu 11G oct. 14 10:04 prod.qcow2 I'd like to make it bigger, like 7,7G -rw------- 1 libvirt-qemu libvirt-qemu 100G oct. 14 10:04 prod.qcow2 AFAIU, the steps would be - power off the VM - expand the qcow2 file size - from the host, extend the volume - power on the VM - from the guest, extend the filesystem I've seen various post on the internet but I'm a bit confused and some posts may be to old to consider new libvirt/qemu possibilities, so I'd appreciate a safe pointer. (I'm also interested in reducing file size.) Thanks for any hint. [1] https://github.com/Jerome-github/vmbackup -- Jérôme

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[libvirt-users] "Failed to start domain..."
by Ken D'Ambrosio 01 Dec '15

01 Dec '15

Sadly, I'm back with another issue. I can do a "system list --all" just fine; however, if I attempt to start the machines, I get back: maas@Bill-MAAS-cc:~$ strace -s 1024 -f -o /tmp/asdfasdf.log virsh -c vbox+ssh://gbadmin@10.20.0.1/system start PXE-client-07 error: Failed to start domain PXE-client-07 error: An error occurred, but the cause is unknown Log files on both client and server are pretty sparse on details of any sort... as, again, is Google. Any ideas? Thanks yet again, -Ken

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[libvirt-users] enabling virtio-scsi-data-plane in libvirt
by Vasiliy Tolstov 30 Nov '15

30 Nov '15

Can somebody knows how to enable virtio-scsi-data-plane in libvirt for specific domain? I know that i need to replace "-device virtio-scsi-pci" with "-object iothread,id=io1 -device virtio-scsi-pci,iothread=io1" in qemu, but how can i do this in libvirt? -- Vasiliy Tolstov, e-mail: v.tolstov(a)selfip.ru

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[libvirt-users] How to disable kvm_steal_time feature
by Piotr Rybicki 30 Nov '15

30 Nov '15

Hi. I would like to workaround a bug, when after live-migration of KVM guest, there is a 100% steal time shown in guest. I've read, that disabling 'kvm_steal_time' feature should workarund this bug, but i can't find a way to disable it in libvirt's domain xml file. Tried in <cpu> section: <feature policy='disable' name='kvm_steal_time'/> but that doesn't work. Also, couldn't find any related information in libvirt documentation. Google helps neither. How can I disable this feature? Thanks in advance. Piotr Rybicki

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[libvirt-users] virsh uses internally qemu-img ?
by Lentes, Bernd 30 Nov '15

30 Nov '15

Hi, i read that virsh uses internally qemu-img (http://serverfault.com/questions/692435/qemu-img-snapshot-on-live-vm) Is that true ? so snapshotting a running vm with virsh or qemu-img is the same ? Bernd -- Bernd Lentes Systemadministration institute of developmental genetics Gebäude 35.34 - Raum 208 HelmholtzZentrum München bernd.lentes(a)helmholtz-muenchen.de phone: +49 (0)89 3187 1241 fax: +49 (0)89 3187 2294 Wer Visionen hat soll zum Hausarzt gehen Helmut Schmidt Helmholtz Zentrum Muenchen Deutsches Forschungszentrum fuer Gesundheit und Umwelt (GmbH) Ingolstaedter Landstr. 1 85764 Neuherberg www.helmholtz-muenchen.de Aufsichtsratsvorsitzende: MinDir'in Baerbel Brumme-Bothe Geschaeftsfuehrer: Prof. Dr. Guenther Wess, Dr. Nikolaus Blum, Dr. Alfons Enhsen Registergericht: Amtsgericht Muenchen HRB 6466 USt-IdNr: DE 129521671

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