- Users - libvirt List Archives

[libvirt-users] Access to virtualization on a multi-user system
by sbaugh＠catern.com 08 Jul '15

08 Jul '15

Hi libvirt-users, I find myself wanting to do something that seems like it must have some obvious solution: I have multiple users (let's just assume local Unix accounts) on a Linux system, and I want them all to have access to KVM-accelerated virtualization. But, I don't want them to be able to meddle with each other's virtual machines. Is there a solution to this problem? Methods of attack that have occured to me: - Use PolicyKit to only allow a user to access qemu:///system VMs that are somehow marked as owned by that user - Run multiple libvirt qemu:///system daemons and restrict access to each on a per-user basis - Allow qemu:///session VMs to actually be KVM-accelerated (this seems like the best way to do it, but I have no idea if that's even possible) Again, the third seems like the best way, but I'm not sure of how to allow such VMs to be KVM-accelerated, and not sure if it's possible for them to use anything other than usermode networking. Hopefully I'm missing some obvious way to do it! Thanks for any assistance!

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[libvirt-users] Error attaching tape drive device to KVM guest
by Jake Kugel 06 Jul '15

06 Jul '15

Hello, i'm trying to configure a host SCSI device (tape drive) so that it is available in a KVM guest VM, but am receiving an error when attempting to attach the device. My guest xml has the following scsi controller defined: <controller type='scsi' index='0' model='virtio-scsi'> <alias name='scsi0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </controller> I created tapedrive.xml with following contents: <disk type='block' device='lun' sgio='unfiltered'> <driver name='qemu' type='raw' cache='none'/> <source dev='/dev/st0'/> <target dev='st0' bus='scsi'/> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </disk> I then attempt to attach using following command, and receive this error: # virsh attach-device instance-0000002d tapedrive.xml --config error: Failed to attach device from tapedrive.xml error: internal error: Invalid harddisk device name: st0 Does anyone know cause of the error? In <address> section of tape drive definition I am using type='drive', I tried type='tape' also but same error. is there a different property value I should use here, or general advice for attaching tape drive to KVM guest? Thanks, Jake

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[libvirt-users] Slow network performance issues
by Alex Regan 03 Jul '15

03 Jul '15

Hi, I have a fedora21 system that's been running fine under normal network activity, but trying to perform a full backup of the 300GB filesystem is taking forever because the network speed appears to be very slow. Using rsync, the transfer speeds reach a max of like 180kB/s. Using rsync to copy files on the local filesystem is greater than 55MB/s, so I don't think it's a disk issue. What kind of network speed can I expect copying data across the network from the guest to another host on the same gigabit network? I'm using the virtio driver: # lsmod|grep virtio virtio_console 28672 0 virtio_balloon 16384 0 virtio_net 32768 0 virtio_blk 20480 4 virtio_pci 24576 0 virtio_ring 20480 5 virtio_blk,virtio_net,virtio_pci,virtio_balloon,virtio_console virtio 16384 5 virtio_blk,virtio_net,virtio_pci,virtio_balloon,virtio_console ethtool on the vnet0 interface shows the speed at only 10Mb/s. Is that normal? Or even changable? I've included the qemu command-line below. # ps ax|grep propguest 1582 ? Sl 25433:37 /usr/bin/qemu-system-x86_64 -machine accel=kvm -name propguest -S -machine pc-1.2,accel=kvm,usb=off -m 16384 -realtime mlock=off -smp 4,sockets=4,cores=1,threads=1 -uuid b67e10fe-7ef0-a1ca-cecf-3f3506d54e1a -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/propguest.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x5 -drive file=/var/lib/libvirt/iso-images/Fedora-18-x86_64-DVD.iso,if=none,id=drive-ide0-1-0,readonly=on,format=raw -device ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -drive file=/var/lib/libvirt/images/propguest.img,if=none,id=drive-virtio-disk0,format=qcow2 -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x6,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive file=/var/lib/libvirt/images/propguest-2.img,if=none,id=drive-virtio-disk2,format=raw -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x9,drive=drive-virtio-disk2,id=virtio-disk2 -netdev tap,fd=23,id=hostnet0,vhost=on,vhostfd=24 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:11:66:5a:51,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev spicevmc,id=charchannel0,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 -device usb-tablet,id=input0 -spice port=5900,addr=127.0.0.1,disable-ticketing,seamless-migration=on -device qxl-vga,id=video0,ram_size=67108864,vram_size=67108864,bus=pci.0,addr=0x2 -device intel-hda,id=sound0,bus=pci.0,addr=0x4 -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x8 Any ideas greatly appreciated. Thanks, Alex

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[libvirt-users] qemu-img snapshots configuration
by sergio 30 Jun '15

30 Jun '15

Hello. What it the difference in external snapshot configuration with and without <domainsnapshot> ? What is the difference between vda and vdb in the following example? (From https://libvirt.org/formatsnapshot.html) <domainsnapshot> ... <memory snapshot='no'/> <disks> <disk name='vda' snapshot='external'> <driver type='qcow2'/> <source file='/path/vda-delta.qcow2'/> </disk> <disk name='vdb' snapshot='no'/> </disks> <domain> ... <devices> <disk type='file' device='disk'> <driver name='qemu' type='raw'/> <source file='/path/vda-img.qcow2'/> <target dev='vda' bus='virtio'/> </disk> <disk type='file' device='disk' snapshot='external'> <driver name='qemu' type='raw'/> <source file='/path/vdb-img.qcow2'/> <backingStore type='file'> <format type='qcow2'/> <source file='/path/vdb-delta.qcow2'/> </backingStore> <target dev='vdb' bus='virtio'/> </disk> ... </devices> </domain> </domainsnapshot> -- sergio.

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[libvirt-users] QEMU-KVM and bare metal performance impact
by nishtala 30 Jun '15

30 Jun '15

Hi, My name is Rajiv Nishtala and I am a PhD student in UPC. I am trying to investigate the performance (instructions per second (IPS)) impact of an application on QEMU-KVM and bare metal using the performance monitoring tools perfmon and perf. The performance counter used for measuring this is "instructions" and "instructions_retired" on perf and perfmon, respectively. The application is a *stress* microbenchmark that does not produce any cache misses (LLC). I account for the performance of the application on QEMU-KVM using the following procedure: A) Record the IPS of the QEMU-KVM (using its PID) on perf and perfmon when idle. B) Launch the stress benchmark and record IPS. C) the difference between *B* and *A* should give the performance of the application since the KVM does not inherently provide a technique to collect this statistic. However the performance of the application on bare metal is recorded as is using the per-thread session available in perfmon and perf. The sampling frequency to collect the statistics is 1 second. The result obtained on bare metal are in the order of magnitude of billions. On the other hand, results from KVM do not show any difference in performance when idle or when an application is running and is in the order of magnitude of 100's of thousands. IPS_KVM_IDLE LLC_KVM_IDLE IPS_KVM_STRESS LLC_KVM_STRESS IPS_bare metal_STRESS LLC_bare metal_STRESS 47902 2495 25157 600 8116556011 3805 23437 758 48762 1032 8166564000 2140 834370 9954 543690 2379 8326333629 234 25261 662 49139 997 8057453733 1399 47998 2767 23773 600 8214761042 494 542039 2299 843266 2231 8075529487 4593 47982 2781 25249 603 8327678364 443 23833 794 49138 622 8058893864 1870 832913 9978 544567 2204 8210889659 394 I also tried using perf-kvm using the following command: sudo perf kvm --guest --guestkallsyms=guest-kallsyms --guestmodules=guest-modules record -a -o perf.data but failed with the following error: *Couldn't record guest kernel [0]'s reference relocation symbol. *and no events were recorded. I describe details of QEMU and the host machine (bare metal) below. QEMU emulator version 2.0.0 in conjunction with KVM as the virtual environment and libvirt 1.2.2 The guest machine is running kernel version 3.19.0-15-generic and the host machine is running version 3.14.5-031405-generic on a x86_64 machine I setup the guest machine with Intel SandyBridge processor (model name:Intel Xeon E312xx) with the following flags: sockets=2,cores=2,threads=1 and 4mb cache. More details: cpu family : 6 model : 42 max freq : 2394.560 MHz flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx rdtscp lm constant_tsc rep_good nopl eagerfpu pni pclmulqdq vmx ssse3 cx16 pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx hypervisor lahf_lm vnmi ept xsaveopt The host machine is an Intel Sandy Bridge processor (Intel(R) Core(TM) i7-2760QM CPU @ 2.40GHz) with 4 cores and 6mb cache. cpu family : 6 model : 42 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 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 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer aes xsave avx lahf_lm ida arat epb xsaveopt pln pts dtherm tpr_shadow vnmi flexpriority ept vpid Thanks Rajiv Nishtala WARNING / LEGAL TEXT: This message is intended only for the use of the individual or entity to which it is addressed and may contain information which is privileged, confidential, proprietary, or exempt from disclosure under applicable law. If you are not the intended recipient or the person responsible for delivering the message to the intended recipient, you are strictly prohibited from disclosing, distributing, copying, or in any way using this message. If you have received this communication in error, please notify the sender and destroy and delete any copies you may have received. http://www.bsc.es/disclaimer

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[libvirt-users] qemu-img snapshots configuration
by sergio 30 Jun '15

30 Jun '15

Hello. What it the difference in external snapshot configuration with and without <domainsnapshot> ? What is the difference between vda, vdb and vdc in the following example? (From https://libvirt.org/formatsnapshot.html) <domainsnapshot> ... <memory snapshot='no'/> <disks> <disk name='vda' snapshot='external'> <driver type='qcow2'/> <source file='/path/vda-delta.qcow2'/> </disk> <disk name='vdb' snapshot='no'/> <disk name='vdc' snapshot='no'/> </disks> <domain> ... <devices> <disk type='file' device='disk'> <driver name='qemu' type='raw'/> <source file='/path/vda-img.qcow2'/> <target dev='vda' bus='virtio'/> </disk> <disk type='file' device='disk' snapshot='external'> <driver name='qemu' type='raw'/> <source file='/path/vdb-img.qcow2'/> <target dev='vdb' bus='virtio'/> </disk> <disk type='file' device='disk' snapshot='external'> <driver name='qemu' type='raw'/> <source file='/path/vdc-img.qcow2'/> <backingStore type='file'> <format type='qcow2'/> <source file='/path/vdc-delta.qcow2'/> </backingStore> <target dev='vdc' bus='virtio'/> </disk> ... </devices> </domain> </domainsnapshot> -- sergio.

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[libvirt-users] Compiling Libvirt-snmp on VMware Vsphere ESXi
by Aleem Akhtar 28 Jun '15

28 Jun '15

How can I compile and run Libvirt-snmp on VMware Vsphere ESXi? Can somebody guide me with step by step procedure. I tried to followed steps mentioned on Libvirt Website <https://libvirt.org/compiling.html> but I guess they are for Linux distribution. Because I could not execute ./configure command. After searching on Google I found a similar question <https://communities.vmware.com/thread/514078> which tells that I need to create a VIB and than install that VIB. Now I have no idea about creating VIB. Can somebody please guide me on this. *Regards,* *Aleem Akhtar * *Lecturer Computer Science* Punjab Group of Colleges P. D. Khan Campus Email: aleem.akhtar(a)seecs.nust.edu.pk <aleem.akhtar(a)seecs.nust.edu.pk> Website: aleemakhtar.com

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[libvirt-users] Snapshots vs filesystem shares
by anonym 27 Jun '15

27 Jun '15

[Please keep me Cc:ed since I'm not subscribed to the list!] Hi list, The tl;dr; is: with Libvirt/QEMU, should it be possible to mount a filesystem share (of type='mount') after restoring from a snapshot that was taken when the filesystem share wasn't mounted? It's pretty clear that Libvirt/QEMU (currently, at least) doesn't support taking snapshots of a live guest which has active filesystem shares (type='mount'). I get this error: Call to virDomainSaveFlags failed: internal error: unable to execute QEMU command 'migrate': Migration is disabled when VirtFS export path '${TARGET_PATH}' is mounted in the guest using mount_tag '$TAG' (Libvirt::Error) I have a use case where I very much would like this combination. It wouldn't be a problem if the filesystem shares would have to be temporarily unmounted while taking the snapshot, and mounted again after restoring it. However, while trying that, `mount` hangs when trying to mount a filesystem share again *after* restoring the snapshot (unmounting and remounting works perfectly before that, of course). Nothing is reported in syslog. I've also tried unloading combinations of the various 9p and virtio related modules (like 9p, 9pnet_virtio, 9pnet, virtio, etc) before taking the snapshot, and then reload them after restoring it, in hope of getting them into a sane state again (or whatever is the issue). But then I've seen errors like this in syslog: 9pnet: Installing 9P2000 support virtio-pci 0000:00:08.0: irq 42 for MSI/MSI-X virtio-pci 0000:00:08.0: irq 43 for MSI/MSI-X virtio-pci 0000:00:08.0: irq 42 for MSI/MSI-X virtio-pci 0000:00:08.0: irq 43 for MSI/MSI-X 9pnet_virtio: probe of virtio3 failed with error -2 FS-Cache: Loaded 9p: Installing v9fs 9p2000 file system support FS-Cache: Netfs '9p' registered for caching 9pnet_virtio: no channels available and `mount` complains that the source (tag) doesn't exist when trying to mount the filesystem share again. For the record, the mount command I always use is simply: mount -t 9p -o trans=virtio $TAG $TARGET_DIR I've tried setting `-o debug=0xfff` but I get no debug info at all. Is it expected behaviour that filesystem shares get into a broken state after restoring a snapshot? If it's of any relevance, here's some more context: * The host is running Debian Jessie with Linux 3.16.7-ckt9-3~deb8u1, Libvirt 1.2.9, QEMU 2.1. * The guest is Tails (https://tails.boum.org) which is Debian Wheezy with Linux 3.16.7-ckt9-3. I doubt it matters since I tested this ~two years ago, and got (IIRC) the exact same results. Cheers!

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[libvirt-users] ANNOUNCE: Oz 0.14.0 release
by Chris Lalancette 26 Jun '15

26 Jun '15

All, I'm pleased to announce release 0.14.0 of Oz. Oz is a program for doing automated installation of guest operating systems with limited input from the user. Release 0.14.0 is a bugfix and feature release for Oz. Some of the highlights between Oz 0.13.0 and 0.14.0 are: * Fix a bug in checksum checking (this should work again) * Add a global lock around pool refresh; should get rid of a user-visible failure * Support for Debian 8 * Support for Ubuntu 15.04 * Support for Fedora 22 * Support for installing aarch64 guests * Support for installing POWER guests * Support for install arm 32-bit guests A tarball and zipfile of this release is available on the Github releases page: https://github.com/clalancette/oz/releases . Packages for Fedora-21, Fedora-22, EPEL-7, and EPEL-6 have been built in Koji and will eventually make their way to stable. Instructions on how to get and use Oz are available at http://github.com/clalancette/oz/wiki . If you have questions or comments about Oz, please feel free to contact me at clalancette at gmail.com, or open up an issue on the github page: http://github.com/clalancette/oz/issues . Thanks to everyone who contributed to this release through bug reports, patches, and suggestions for improvement. Chris Lalancette

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[libvirt-users] "connect at power-on" NIC feature equivalent to that found in ESX
by Ryan, Lyle 25 Jun '15

25 Jun '15

With ESX and the vSphere Client, I can enable or disable a VM's NIC to "connect at power-on". This is very useful when cloning, since you can leave the NIC not connected, power-up the VM, connect to it's console, and modify ifcfg-eth0 etc, before bringing the VM online. Is there a virsh equivalent way of doing this. Thanks....Lyle

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