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[libvirt-users] virsh blockcopy: doesn't seem to flatten the chain by default
by Kashyap Chamarthy 04 Jul '14

04 Jul '14

Versions -------- (Libvirt locally built from a recent git commit -ec7b922): $ rpm -q libvirt-daemon-kvm qemu-system-x86 libvirt-daemon-kvm-1.2.6-1.fc20.x86_64 qemu-system-x86-2.0.0-1.fc21.x86_64 Test ---- [All images are qcow2 files.] We have this simple chain: base <- snap1 Let's quickly examine the contents of 'base' and 'snap1' images: 'base' has just a single file: foo $ guestfish --ro -a base.qcow2 [. . .] ><fs> ls / ><fs> run ><fs> mount /dev/sda1 / ><fs> ls / foo lost+found ><fs> quit 'snap1' has files: bar, baz, jazz $ guestfish --ro -a snap1.qcow2 [. . .] ><fs> run ><fs> mount /dev/sda1 / ><fs> ls / bar baz jazz lost+found ><fs> Now, let's do a live blockcopy (with a '--finish' to graecully finish the mirroring): $ virsh blockcopy --domain testvm2 vda \ /export/dst/copy.qcow2 \ --wait --verbose --finish Examine the contents of the above 'copy': $ guestfish --ro -a copy.qcow2 [. . .] ><fs> run ><fs> mount /dev/sda1 / ><fs> ls / bar baz jazz lost+found ><fs> quit If I'm reading the man page of 'blockcopy' correctly, shouldn't it 'flatten' the entire chain, by also copying the contents of base into copy.qcow2? i.e. the 'copy' should have files (including the file foo from 'base': foo, bar, baz, jazz True or false? PS: I've tested the cases of --pivot, --shallow and --reuse-external, will post my notes about them on a wiki. -- /kashyap

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[libvirt-users] Acces to hypervisor from a KVM guest
by Jean-Pierre Ribeauville 04 Jul '14

04 Jul '14

Hi, >From a KVM guest, I want to retrieve the hostname of the host on which the hypervisor is running. Before doing that by using libvirt API, I first try via virsh. So, I run virsh and the run hostname command.( got that in virsh help : .... hostname print the hypervisor hostname ....) Unfortunately, I got following error when starting virsh : error: Failed to reconnect to the hypervisor error: no valid connection error: internal error Unable to locate libvirtd daemon in /usr/sbin (to override, set $LIBVIRTD_PATH to the name of the libvirtd binary) Do I miss to install some package on my KVM guest ? or is it not the right way to get this information ? Any help is welcome. Thx. [cid:image001.png@01CF75CE.35F97F50] Jean-Pierre RIBEAUVILLE Developer Tel: 01 49 11 45 81 Discover Systar's Videos!<https://www.youtube.com/channel/UCvyaJkMXCGFo8_XZYd9rcBw> P Please consider the environment before printing this e-mail

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[libvirt-users] os/type/machine/pc-xxxx meaning ? following live migration issue after an upgrade
by Benoit Rousselle 04 Jul '14

04 Jul '14

Dear All, I have upgrade my hypervisors: qemu-kvm 0.12.5 => 1.1.2 libvirt-bin 0.8.3-5 => 0.9.12.3 (debian6 to debian7) After that upgrade, i noticed that live migration was most of the time failing (freeze) (not always) I also noticed that creating a machine with the updated hypervisor was always working. After some days of investigation mainly on network side, i found this setting that seems to fix the issue in the xml: <os> <type arch='x86_64' machine='pc-0.12'>hvm</type> <boot dev='hd'/> </os> replacing pc-0.12 with pc-1.1 seems to fix the issue. Here are my questions : 1) what is the meaning/purpose of that setting ? (i guess it is somehow linked to the version of kvm ;) ) 2) can i just change it in all xmls ? ( i have plenty of linux/windows flavors running in my vms) 3) is it possible to put a more generic value? So we don't have the same issue on next upgrade. 4) Is there a script/doc that explains what needs to be done on the vm itself (xml or other) when we upgrade libvirt/kvm ? Thanks for the feedback ! Benoit. -- Benoit Rousselle

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[libvirt-users] getting CPU usage of VMs through libvirt
by Restituto Marcus Arevalo 03 Jul '14

03 Jul '14

Greetings everyone, I just want to ask if it is possible to get the CPU usage of the VMs in KVM through libvirt? I mean, how does the virt-manager produce the graph it displays? Is there a way get this graph? But instead of the graph itself, I just need to get it in percentage(%) form. I'd like to know how. Thank you and your help will be greatly appreciated. regards, Marco

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[libvirt-users] Domain Storage type
by Sijo Jose 03 Jul '14

03 Jul '14

Hi, How can we identify a domain is using Shared storage OR Non shared storage using libvirt -API? Rgds -Sijo

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[libvirt-users] How can I setup a privileged container
by WANG Cheng D 02 Jul '14

02 Jul '14

Dear all, I want to setup a privileged container, which means I can set the priority of a process to SCHED_RR (real-time) dynamically by calling sched_setscheduler() in a C program running on a container. In my system (host: fedora19, container: fedora19, libvirt 1.2.5), my C code reports "operation not permitted" when sched_setscheduler() is called. I found a link (https://www.redhat.com/archives/libvir-list/2014-June/msg00562.html) which is talking about container capability drops and keeps, but only "nice" is mentioned and I don't know how to turn on "priority" feature on a container? Any comments are highly appreciated. Cheng

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[libvirt-users] all windows vm could not start because the following file is missing or corrupt
by Lucas -LandM- 02 Jul '14

02 Jul '14

Hi, After some problems in the server I can't start windows XP virtual machines. - Yesterday we got full disk (100%). I deleted some files. Solved. - I update Centos 5.6. I guess libvirt was updated from 0.9 to 0.10. We have to use this kernel: 2.6.32-042stab079.6 because this bug is not in the release: https://bugzilla.openvz.org/show_bug.cgi?id=2915 Now, I try to start windows XP machines and all give me same error could not start because the following file is missing or corrupt c:\WINDOWS\SYSTEM32\CONFIG\SYSTEM If this error were in a particular VM I try to solve it manually, but same error in three diferent VM is not a coincidence. I suppose it is a upgrade issue. What should I do? Thanks in advanced, Lucas

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[libvirt-users] changing the priority of a process in the container is not permitted
by WANG Cheng D 02 Jul '14

02 Jul '14

Dear all, I want to run a process in a container with a real-time (RT) priority. When the sched_setscheduler(0, SCHED_RR, &sparam) is called in the container, an error is reported which is "operation not permitted" I had added the following line in the file /etc/security/limits.conf for both the host and the container, which means allowing all users to change the priority of the process, but it still doesn't work. * - rtprio 100 I wonder how to change the privilege of a container so that it has the similar privilege of the root user of the host. Thank you in advance Cheng

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[libvirt-users] Libvirt installion error: You must install the libyajl library & headers to compile libvirt
by WANG Cheng D 02 Jul '14

02 Jul '14

Dear all, I am installing the libvirt 1.2.5 on my newly installed Fedora19. When I run ./configure, an error is reported: "You must install the libyajl library & headers to compile libvirt" In fact, the package yajl-2.0.4-2fc19.x86_64.rpm has been installed on the fedora19. I found several links talking about this error and I downloaded 3 files (configure.ac, m4/virt-yajl.m4, src/qemu/qemu_capabilities.c) from the link given by Daniel Berrange (http://libvirt.org/git/?p=libvirt.git;a=commit;h=654c709baaa6fdcff6b6d38abb…) , but it does not work. Am I missing something? Best regards, Cheng

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[libvirt-users] virsh update-device issues
by Oleg Bondarev 01 Jul '14

01 Jul '14

Hi, I faced a couple of issues with libvirt update-device function: 1. http://libvirt.org/hvsupport.html says that virDomainUpdateDeviceFlags is supported since 0.8.0 API version in qemu driver. However when trying to update network device (changing source bridge of the interface) on Ubuntu with 0.9.8 libvirt version I get the following error: "*this function is not supported by the connection driver: cannot modify network device configuration"* What may be the reason for such error? 2. Not able to rename target device name of an interface. For example if have running instance with interface: * <interface type='bridge'>* * <mac address='fa:16:3e:80:f4:49'/>* * <source bridge='qbre1894135-13'/>* * <target dev='vnet0'/>* * <model type='virtio'/>* * <alias name='net0'/>* * <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>* * </interface>* and then try to update: *$ sudo virsh update-device --persistent --config --live 1 dev.xml* where dev.xml: * <interface type='bridge'>* * <mac address='fa:16:3e:80:f4:49'/>* * <source bridge='qbre1894135-13'/>* * <target dev='tap123'/>* * <model type='virtio'/>* * </interface>* I get: * error: Failed to update device from dev.xml* * error: Operation not supported: cannot modify network device tap name* This happens even if rename vnet0 to tap123 manually with *ip link set vnet0 name tap123* before interface update. And after instance reboot tap123 is renamed back to vnet0. Is there a strong reason to not allow modifying network device tap name? Will appreciate any assistance with the described issues. Thanks, Oleg

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