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[libvirt-users] Creating external snapshots with logical volumes.
by Dominique Ramaekers 27 Jun '16

27 Jun '16

Hi, Quick question regarding external snapshots. Currently, for making backups of my guests, I use external snapshots like this: virsh snapshot-create-as --domain PCVIRTdra --disk-only --atomic --quiesce --no-metadata --diskspec vda,file=/srv/poolVMS/PCVIRTdra-ONDERHOUD If I wanted to use a logical volume as destination behind the '--diskspec' option, can I do this like this? virsh snapshot-create-as --domain PCVIRTdra --disk-only --atomic --quiesce --no-metadata --diskspec vda,file=/dev/CmsrvVH3-vg/PCVIRTdra-ONDERHOUD It seems to work, but if this is never intended to be used like this, I would rather not... I ask this question because it seems libvirt is actually recognizing the logical volume as a file: root@CmsrvVH3:~# virsh domblklist PCVIRTdra --details Type Device Target Source ------------------------------------------------ file disk vda /dev/CmsrvVH3-vg/PCVIRTdra-ONDERHOUD file cdrom hdb /srv/poolVMS/Windows10_x64.iso file cdrom hdc /srv/poolVMS/virtiodrivers.iso Is there a better way of doing this? Thanks in advance, Dominique.

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[libvirt-users] block commit failed at 100%
by Ishmael Tsoaela 27 Jun '16

27 Jun '16

Hi All, I am new to libvirt and would appreciated some assistance with libvirt backups. I am backing up some VM and coming accross and issue where "Block commit" does not completely finish, causing libvirt to write to snapshot: root@xxx:~# virsh blockjob vm /mnt/diskimage-backups/vm.snap-201606210230.qcow2 --info Active Block Commit: [100 %] The state does not change, is the anyway around this ? libvirtd (libvirt) 1.3.4 QEMU emulator version 2.3.0

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[libvirt-users] Problem executing VM backups
by Markus Ellinger 24 Jun '16

24 Jun '16

Hi everyone, we are suddenly having a problem with executing our backup jobs. For a long time, we have used a shell script which contains the following code to backup all our virtual machines: for domain in Testserver Faktura Fileserver Gitolite Jenkins Nexus SimpleHelp VpnGateway Wiki; do echo -n "$(date +"%Y-%m-%d %H:%M:%S") starting backup for vm ${domain} ... " >> ${vmlog} virsh dumpxml --security-info ${domain} > ${vmdir}/${domain}.xml virsh undefine ${domain} >> ${vmlog} virsh blockcopy ${domain} /var/lib/libvirt/images/${domain}.img ${vmdir}/${domain}.img --wait --finish >> ${vmlog} virsh define ${vmdir}/${domain}.xml >> ${vmlog} done This has worked great for us, but all of the sudden (eventually triggered by an update, since of course we do regular security/package updates on this machine) we are having problems. For some virtual machines, it still works perfectly, but for others, virsh tells us that a blockjob is still active and therefore the backup fails. This seems to happen to machines at random. However, when we then try to query the active blockjob, virsh tells us that no blockjob is active. Consider the following log from the shell: root@gfii-host:~# virsh undefine Gitolite error: Failed to undefine domain Gitolite error: Requested operation is not valid: cannot undefine transient domain root@gfii-host:~# virsh blockcopy Gitolite /var/lib/libvirt/images/Gitolite.img /tmp/test-blockcopy-gitolite.img --wait --finish error: block copy still active: disk 'vda' already in active block job root@gfii-host:~# virsh blockjob Gitolite /var/lib/libvirt/images/Gitolite.img No current block job for /var/lib/libvirt/images/Gitolite.img root@gfii-host:~# virsh define /var/local/backup/vms/2016-06-22T013001/Gitolite.xml error: Failed to define domain from /var/local/backup/vms/2016-06-22T013001/Gitolite.xml error: block copy still active: domain has active block job Of course we tried to start/stop the virtual machines, rebooted the whole host multiple times etc., but the problem comes back every night. The machine is a Debian Wheezy machine with current updates. We are using the qemu-kvm package from wheezy-backports to enable blockcopy support. Best regards Markus

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[libvirt-users] virt-sparsify changing the apparent-size of files
by libvirt_users＠skagitattic.com 23 Jun '16

23 Jun '16

Hello, I am curious why when using virt-sparsify the apparent-size of the file gets reduced to the actual file size? Is there a way to get the apparent-size left as the full size? In the man page for virt-sparsify it has a section on "IMPORTANT NOTE ABOUT SPARSE OUTPUT IMAGES" and its output seems to indicate what I would expect where "ls -lh" shows the full apparent size and "du -sh" shows the actual size. But my actual results from testing are different. In the following example input.qcow2 is before sparsify and output.qcow2 is after. Doing ls reports full size for input but a small size for the output: root@testingbox:/tmp/test # ls -lh total 3.1G -rw-r--r-- 1 root root 512M Jun 14 22:30 file.img -rw-r--r-- 1 root root 51G Jun 14 22:30 input.qcow2 -rw-r--r-- 1 root root 790M Jun 14 22:36 output.qcow2 Same when asking du for apparent-size: root@testingbox:/tmp/test # du -h --apparent-size * 512M file.img 51G input.qcow2 790M output.qcow2 A normal du will show the actual size of the files: root@testingbox:/tmp/test # du -h * 0 file.img 2.4G input.qcow2 790M output.qcow2 The only way I have found to check the full virtual size of the file after virt-sparsify is with qemu-img: root@testingbox:/tmp/test # qemu-img info input.qcow2 image: input.qcow2 file format: qcow2 virtual size: 50G (53687091200 bytes) disk size: 2.3G cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: true root@testingbox:/tmp/test # qemu-img info output.qcow2 image: output.qcow2 file format: qcow2 virtual size: 50G (53687091200 bytes) disk size: 789M cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false Thanks!

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[libvirt-users] Problem with guest cpu feature
by Laurent Pouilloux 23 Jun '16

23 Jun '16

Hello libvirt-users, I have an issue with libvirt on Centos 7.2 regarding CPU features seen by the Guest OS. The physical Host is Dell PowerEdge R730 with Haswell CPU, with the following features $ grep "model name" /proc/cpuinfo | tail -1 model name : Intel(R) Xeon(R) CPU E5-2640 v3 @ 2.60GHz $ grep flags /proc/cpuinfo | tail -1 flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm ida arat epb pln pts dtherm tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid cqm xsaveopt cqm_llc cqm_occup_llc Regarding libvirt configuration, we have the following features detected : $ virsh capabilities | grep feature <feature name='invtsc'/> <feature name='abm'/> <feature name='pdpe1gb'/> <feature name='rdrand'/> <feature name='f16c'/> <feature name='osxsave'/> <feature name='dca'/> <feature name='pdcm'/> <feature name='xtpr'/> <feature name='tm2'/> <feature name='est'/> <feature name='smx'/> <feature name='vmx'/> <feature name='ds_cpl'/> <feature name='monitor'/> <feature name='dtes64'/> <feature name='pbe'/> <feature name='tm'/> <feature name='ht'/> <feature name='ss'/> <feature name='acpi'/> <feature name='ds'/> <feature name='vme'/> We have created a VM named that is configured with match="exact" $ virsh dumpxml compil | grep -A2 match <cpu mode='custom' match='exact'> <model fallback='allow'>Haswell-noTSX</model> </cpu> However, on the guest side, there no feature such as f16c is detected $ grep flag /proc/cpuinfo | tail -1 flags : fpu de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx rdtscp lm constant_tsc rep_good nopl eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx hypervisor lahf_lm fsgsbase bmi1 avx2 smep bmi2 erms invpcid xsaveopt Is this normal ? Should we use match="strict" to have the f16c feature seen by the guest OS ? The xml file describing both the host and the guest are in attachment. $ yum info libvirt Modules complémentaires chargés : fastestmirror Loading mirror speeds from cached hostfile Paquets installés Nom : libvirt Architecture : x86_64 Version : 1.2.17 Révision : 13.el7_2.4 Taille : 0.0 Dépôt : installed Depuis le dépôt : updates Résumé : Library providing a simple virtualization API URL : http://libvirt.org/ Licence : LGPLv2+ Description : Libvirt is a C toolkit to interact with the virtualization capabilities : of recent versions of Linux (and other OSes). The main package includes : the libvirtd server exporting the virtualization support. Thanks in advance for any advices we can receive. Best regards, Laurent Pouilloux -- Ingénieur en Calcul Scientifique Laboratoire de Mécanique des Fluides et d'Acoustique École Centrale de Lyon 36 Avenue Guy de Collongue, 69130 Écully Batiment I11 - Bureau 11097W Tél : 04.72.18.61.57

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[libvirt-users] Need information
by Gk Gk 20 Jun '16

20 Jun '16

Hi, I am referring to the 'Routed Mode' section just under the section 'Other virtual network switch routing types' in the URL ' http://wiki.libvirt.org/page/VirtualNetworking#Routed_mode'. In the above link, for routed mode, it is stated that 'In this mode all virtual machines are in a subnet routed through the virtual switch.' Can anyone explain to me, if the guest machines have to be in the same subnet as the Host machine for the routed mode to work (o)r can the guest machines be in any subnet different from the host machine in routed mode ? Thanks Kumar

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[libvirt-users] libvirt can't communicate over network while creating VM
by Mensik, Petr 16 Jun '16

16 Jun '16

Hello guys, we use libvirt for dynamic creation of our VM and we do various modifications of those VMs in the process. One with I am struggling with is to signing keys of our custom repository - " vm.sh("wget -O - " + key_address + " | apt-key add -")" where "vm" is a GuestFS object. So I have set "vm.set_network(True)" and I have installed "dhcpcd5" package (that's whats on Debian Jessie) on both Host OS with KVM running and VM template (because we always copy Debian template we have in order to create new VM). However according to the log libvirt is still complaining that dhcpcd is missing (line 371 in the log). I ran dhcpcd command on both machines and I've even restarted networking service - unfortunately nothing helps. So I'd like to ask you for help or at least any hints. Thanks a lot. http://pastebin.com/d6zZG1BK P.S. I already wrote to the #libvirt channel on IRC but nobody replied so I am trying my luck here :) Best regards Petr Mensík

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[libvirt-users] CPU reservation.
by Dominique Ramaekers 14 Jun '16

14 Jun '16

Hi, I'd like some opinions regarding the configuration of my guest cpu. I had a physical server with a MSSQL on it. The license of the SQL server was of type 1 processor. This means, only one processor will be used by the SQL server. Recently I had virtualised this server on a 2 processor host. Correct me if I'm wrong, but now I can fool the SQL server by configuring one processors with a lot of cores and threats which results in using more than one physical processor. With a trick like this, I'm not running the server according to the license. To be on the safe side license-wise, I would like to configure my guest that it has only one physical processor at disposal and that this processor is reserved especially for this host. So, the other guests can't use that processor. There is the option cpu passtrough, but I think this will give me trouble when I migrate the guest to another host... There are a lot of possibilities configuring the cpu. What would be the best aproche? Thanks in advance. Dominique.

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[libvirt-users] libvirt-clone - Slow image cloning on a Server
by Philip Banh 14 Jun '16

14 Jun '16

Hello there, I have libvirt/kvm installed on a HP DL380 server and it seems to be cloning a template image very slowly, in fact a 50GB image just doesn't gets stuck after 7%. Is there a reason why this might be happening? I've tried the same setup on a desktop and never had this issue. The command and setup is listed below: virt-clone -o template.img -n new-clone -f .../new-clone.img System - 12 cores, 32 GB of memory - Running CentOS 7 - XFS file system using LVM - Libvirt 1.2.17 Thanks, Philip

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[libvirt-users] Host loses network connectivity when starting containers
by Peter Steele 14 Jun '16

14 Jun '16

I have hit a problem running libvirt based containers in a CentOS 7 based host, with the extra wrinkle that my host is an EC2 instance in AWS. Ultimately everything works as advertised, and I can launch instances that host multiple libvirt lxc containers without problems, with one caveat: About one time in ten when the containers are started, the instance loses all network connectivity. This can even happen on instances that host only a single container, so it's not related to the number of containers that are being run. Once this happens, the only way to fix the problem is to reboot the instance and hope that on the reboot, the containers will start successfully this time. In troubleshooting efforts that I've done I've found that the problem does not occur with containers defined with the linuxcontainers.org flavor of lxc. I've also discovered that if I configure my containers to use libvirt's default isolated bridge device virbr0, this loss of network connectivity does not appear to happen when the containers are started. Specifically, I ran a test that repeatedly started/stopped a single container configured with virbr0 and the test ran for a long time without an issue. When I switched the container to use my fully configured bridge device br0, the start/stop test usually hung up within a few iterations. Meaning that my ssh session into the instance would hang and I'd be unable to reconnect to the instance. Unfortunately AWS does not provide an console back door into an instance so troubleshooting has been difficult. I've checked the system logs though after one of these hangs occurs and there are no errors reported anywhere that I can see. I do not see this problem when running on real hardware. I also do not see the problem when running under other virtual environments, including VMware, KVM, and VirtualBox. My guess is that it is a bug in libvirt (since containers defined with the linuxcontainers.org lxc framework do not cause this issue.) There seems to be an AWS component to the problem as well though since I've only seen this happen in EC2 based instances. Is anyone familiar with this problem? Does anyone have any suggestions how I might resolve it? Note that I have tried a recent version of libvirt (1.3.2-1) and it behaves the same as the stock CentOS version of libvirt (1.2.17-13). Peter

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