- Users - libvirt List Archives

[libvirt-users] Proper way to reference a disk
by Michael Schwager 06 May '15

06 May '15

Hi, We are running on CentOS 7.0. We want to move our VMs (kvm/qemu) from qcow/image files to logical volumes under LVM. I have moved one of them but I had a little trouble editing the disk properly and I wonder what is the correct way to do it. Specifically, in the XML under the devices/disk section why does the source say "source file=", and not "source dev="? The reason I ask is that I have a number of other machines to move and I don't want to mess them up. The source file entry for the disk was like this in our xml file: <source file='/var/lib/libvirt/images/pxetest.qcow2'/> I got the vm to work by converting the image to raw, then dumping via dd into the LV, and editing the XML using virsh as follows: <disk type='file' device='disk'> <driver name='qemu' type='raw' cache='none'/> <*source file*='/dev/kvm_temp/pxetest'/> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </disk> By comparison I have a test machine on another real host upon which I loaded a VM and put its disk into a logical volume. Its disk section looks like this: <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='none' io='native'/> <*source dev*='/dev/kvm_hosts/pxetest2'/> <target dev='hda' bus='ide'/> <address type='drive' controller='0' bus='0' target='0' unit='0'/> </disk> The source file / source dev thing really has me wondering. *- Mike Schwager* * Linux Network Engineer, Mocho Trading LLC* -- This message is for the named person(s) use only. It may contain confidential proprietary or legally privileged information. No confidentiality or privilege is waived or lost by any mistransmission. If you receive this message in error, please immediately delete it and all copies of it from your system, destroy any hard copies of it and notify the sender. You must not, directly or indirectly use, disclose, distribute, print, or copy any part of this message if you are not the intended recipient. Mocho Trading LLC reserves the right to monitor all e-mail communications through its networks. Any views expressed in this message are those of the individual sender, except where the message states otherwise and the sender is authorized to state them to be the views of any such entity.

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[libvirt-users] Using Virtio drivers with kernal 2.6.18-164.el5
by Jatin Davey 06 May '15

06 May '15

Hi All I looked at this page for reference to using virtio drivers on KVM guests. http://wiki.libvirt.org/page/Virtio In the requirements section it is mentioned that we need a virtio compatible guest with kernel >= 2.6.25 One of my guest has this version: [root@localhost ~]# uname -a Linux localhost 2.6.18-164.el5 #1 SMP Thu Sep 3 03:28:30 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux I was still able to use the virtio drivers by enabling the corresponding options in the qemu xml file and also i created a new initrd image file inside my guest using the mkinitrd command as mentioned in the link provided above. My question is , Is it fine to use the virtio drivers with the kernel that i have for my guest or i definitely need to get to kernel version >= 2.6.25 ? Thanks Jatin

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[libvirt-users] Source information not showing for virsh domiflist causing problems with migrating VMs
by Carl J Taylor 05 May '15

05 May '15

Hi, Does anyone know of a way to get around this problem. I have several long running VMs running on an Ubuntu 14.10 host and for some reason I am getting errors when trying to migrate them to another host. If I restart the VM then the problem does not exist, however for various reasons that is not an option with the remaining VMs. root@comp001:~# /root/bin/vm_migrate.sh ws001 comp003 virsh migrate --live --persistent --tunneled --p2p --unsafe --domain ws001 --desturi qemu+tcp://comp003/system error: internal error: No <source> 'bridge' attribute specified with <interface type='bridge'/> I have eventually figure out that the problem is not with the XML definitions for the host, but is related to the details of the network interfaces assigned to the host as output by the virsh domiflist command. The question I need to resolve is how do I populate the missing Source information. Any help gratefully appreciated. Kind regards Carl Taylor root@comp001:~# libvirtd --version libvirtd (libvirt) 1.2.8 root@comp001:~# virsh domiflist --inactive ws001 Interface Type Source Model MAC ------------------------------------------------------- - network br300 virtio 52:54:00:62:9b:20 - network br201 virtio 52:54:00:f0:73:85 - network default virtio 52:54:00:69:b1:e5 root@comp001:~# virsh domiflist ws001 Interface Type Source Model MAC ------------------------------------------------------- vnet18 bridge - virtio 52:54:00:62:9b:20 vnet19 bridge - virtio 52:54:00:f0:73:85 vnet20 network default virtio 52:54:00:69:b1:e5

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[libvirt-users] [Libvirt Users]how to provide password authentication for qemu driver
by Dhaval_Shah1＠dell.com 05 May '15

05 May '15

Dell Customer Communication Hi All, I am using Compiled against library: libvirt 1.2.9 Using library: libvirt 1.2.9 Using API: QEMU 1.2.9 Running hypervisor: QEMU 2.1.2 I want user to provide username and password authentication to virConnectPtr virConnectOpenAuth(const char *name, virConnectAuthPtr auth, unsigned int flags) to login remotely for the qemu hypervisor. But it is not taking user provided username and driver. Because internally it is calling below qemu driver function, static virDrvOpenStatus qemuConnectOpen(virConnectPtr conn, virConnectAuthPtr auth ATTRIBUTE_UNUSED, unsigned int flags) so it is not taking any user provided auth parameters and it is internally calling separate function for prompting password. I don't want to provide password here. In case of windows HyperV it is working fine as it takes auth parameters but for Qemu Hypervisor I am facing this issue since here the auth parameters as marked as ATTRIBUTE_UNUSED. Can anyone help me with this that how can I achieve this? Thanks & Regards, Dhaval Shah

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[libvirt-users] Hyperv on windows 2012 R2 support in libvirt
by doyensundu 04 May '15

04 May '15

Hi, I have been trying to work with libvirt apis to manage hyper-v on windows 2012 r2 server. I had taken patch a modified it to suite the latest code on GITHUB. I could able to connect. But i don't know what else to do and how to use the api's. There is no documentation. I want to use/manage hyper-v to provision guest OS's, configure network, create virtual switch etc. I see few classes ( https://msdn.microsoft.com/en-us/library/cc136822%28v=vs.85%29.aspx) have been implemented in libvirt. The classes include : Msvm_ComputerSystem, Msvm_ConcreteJob, Msvm_MemorySettingData, Msvm_ProcessorSettingData, Msvm_VirtualSystemSettingData, Win32_ComputerSystem, Win32_Processor. I want to know how to use libvirt api's to connect, provision a guest os, configure network. Few examples/guidance would be helpful to me. Thanks surender

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[libvirt-users] Limitations of macvtap devices?
by Lars Kellogg-Stedman 04 May '15

04 May '15

I am running OpenStack inside a libvirt guest that is connected to the local network via a macvtap interface. My experience so far suggests that a macvtap interface will not pass traffic with a source MAC address other than the MAC address of the interface itself...for example, if inside the guest eth0 is attached to a bridge. Is that correct, or is there some setting that will make that work? Outbound traffic doesn't seem to be a problem (I can see, for example, dhcp requests on the local network), but replies get dropped before they reach the guest. Thanks, -- Lars Kellogg-Stedman <lars(a)redhat.com> | larsks @ {freenode,twitter,github} Cloud Engineering / OpenStack | http://blog.oddbit.com/

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[libvirt-users] Improved Shared Folders UX and security
by drift＠ruggedinbox.com 03 May '15

03 May '15

Would it degrade security if libvirt were to handle SELinux labeling of shared folders automatically instead of the manual adjustments needed currently? Would it degrade security if libvirt were allowed to create a non existing shared directory specified in a VM's xml upon import?

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[libvirt-users] SELinux for separate shared folders
by drift＠ruggedinbox.com 02 May '15

02 May '15

How can I enforce SELinux separation between the shared folders belonging to different VMs running with sVirt's SELinux dynamic labels? I want to create a permanent exception for VM 'A' to only be able to read and write to shared folder 'A' and the same for VM 'B' and shared folder 'B' svirt_image_t permits access to a shared folder but for all VMs.

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[libvirt-users] libvirt nwfilter
by drift＠ruggedinbox.com 01 May '15

01 May '15

To take advantage of the filters, is it as simple as adding these couple of lines in a guest's xml file like the example from https://libvirt.org/formatnwfilter.html#nwfconcepts ? <devices> <interface type='bridge'> <mac address='00:16:3e:5d:c7:9e'/> <filterref filter='clean-traffic'> <parameter name='IP' value='10.0.0.1'/> </filterref> </interface> </devices> Can multiple filters be combined together like this? <filterref filter='clean-traffic' filter='no-ip-multicast'> <parameter name='IP' value='10.0.0.1'/> </filterref> Can the IP address parameter override the one in /etc/network/interfaces on the guest? When cloning a vm does it change the ip to avoid conflicts like it would with mac-addresses?

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[libvirt-users] Sometimes libvirt fails to update domain block file after blockcommit.
by Matthew Schumacher 29 Apr '15

29 Apr '15

Posted to https://bugzilla.redhat.com/show_bug.cgi?id=1217185 I just stumbled on another bug while snapshotting and think it's related to 1210903 and 1197592 as it seems like some sort of race condition because it depends on what logging is in place and doesn't happen every time. Here are the details: I wrote this test script to snapshot and commit over and over: #!/bin/sh while [ 1 ]; do echo "Starting snapshot test `date`" virsh snapshot-create-as test 20150429 20150429-backup --disk-only --atomic virsh domblklist test virsh blockcommit test vda --active --pivot --verbose virsh snapshot-delete test 20150429 --metadata virsh domblklist test rm /glustervol1/vm/test/test.20150429 echo "Ending snapshot test `date`" echo echo sleep 2 done If I run libvirtd in the foreground with debug set to 1 I can't get it to fail, it does what it's supposed to do, snapshot and commit over and over. If I run libvirtd in the foreground with debug set to 3, then I will always eventually get this: Starting snapshot test Wed Apr 29 09:34:34 AKDT 2015 Domain snapshot 20150429 created Target Source ------------------------------------------------ vda /glustervol1/vm/test/test.20150429 hdc /dev/sr0 Block Commit: [100 %] Successfully pivoted Domain snapshot 20150429 deleted Target Source ------------------------------------------------ vda /glustervol1/vm/test/test.20150429 hdc /dev/sr0 Ending snapshot test Wed Apr 29 09:34:35 AKDT 2015 Starting snapshot test Wed Apr 29 09:34:37 AKDT 2015 error: unsupported configuration: source for disk 'vda' is not a regular file; refusing to generate external snapshot name Target Source ------------------------------------------------ vda /glustervol1/vm/test/test.20150429 hdc /dev/sr0 error: internal error: qemu block name '/glustervol1/vm/test/test.qcow2' doesn't match expected '/glustervol1/vm/test/test.20150429' error: Domain snapshot not found: no domain snapshot with matching name '20150429' Target Source ------------------------------------------------ vda /glustervol1/vm/test/test.20150429 hdc /dev/sr0 rm: can't remove '/glustervol1/vm/test/test.20150429': No such file or directory Ending snapshot test Wed Apr 29 09:34:37 AKDT 2015 At this point libvirt is confused about which file is the backing store because the first run did pivot after blockcommit, but didn't update the block file. From the logs: 2015-04-29 17:33:41.052+0000: 25192: warning : qemuDomainObjTaint:1972 : Domain id=2 name='test' uuid=4b9cc25b-68d1-4ce8-8a65-2a378e255e36 is tainted: high-privileges 2015-04-29 17:34:37.322+0000: 25191: error : virDomainSnapshotAlignDisks:609 : unsupported configuration: source for disk 'vda' is not a regular file; refusing to generate external snapshot name 2015-04-29 17:34:37.352+0000: 25194: error : qemuMonitorJSONDiskNameLookup:3977 : internal error: unable to find backing name for device drive-virtio-disk0 2015-04-29 17:34:37.354+0000: 25194: error : qemuMonitorJSONDiskNameLookupOne:3914 : internal error: qemu block name '/glustervol1/vm/test/test.qcow2' doesn't match expected '/glustervol1/vm/test/test.20150429' So libvirt insists that the block file is: root@wasvirt2:/glustervol1/vm/waspbx# virsh domblklist test Target Source ------------------------------------------------ vda /glustervol1/vm/test/test.20150429 hdc /dev/sr0 But that file isn't in use and isn't what qemu is using: root@wasvirt2:/glustervol1/vm/waspbx# lsof | grep test 25300 /usr/bin/qemu-system-x86_64 /var/log/libvirt/qemu/test.log 25300 /usr/bin/qemu-system-x86_64 /var/log/libvirt/qemu/test.log 25300 /usr/bin/qemu-system-x86_64 /glustervol1/vm/test/test.qcow2 The only way to straighten this out is to destroy and start the domain.

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