- Users - libvirt List Archives

[libvirt-users] Starting processes inside VMs using Libvirt?
by Taimur Al Said 25 Mar '14

25 Mar '14

Hi there, I am a beginner with Libvirt. I was practicing using Python bindings with libvirt to do some basic stuff like starting a VM, rebooting a VM, displaying the number of domain,etc. I was wondering since the hypervisor has control over the VMs, it is possible to use Libvirt to inject code into the VM? Is it possible to start processes inside a particular VM using the Libvirt API. If not, what would you recommend instead? Thanks in advance Regards, T.alsaid

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[libvirt-users] Clock problems on live migration
by Paul Boven 25 Mar '14

25 Mar '14

Hi everyone, While doing a live migration, Linux guests will frequently get stuck and become unresponsive, while the CPU utilization on the host for that guest goes to 100%. Sometimes they recover, and dmesg then shows that there's been a clock problem during the live migration: Clocksource tsc unstable (delta = 35882846234 ns) So the TSC did a jump of nearly 36 seconds. Migrations often fail when going from server A to B, but will then work fine in the other direction. Both servers are locked to the same NTP source, and are well within 1ms from one another. Both hosts are running Ubuntu 13.04 with these versions (from Ubuntu packages): Kernel: 3.8.0-35-generic x86_64 Libvirt: 1.0.2 Qemu: 1.4.0 Gluster-fs: 3.4.2 (libvirt access the images via the filesystem, not using libgfapi yet). The interconnect between both machines (both for migration and gluster) is 10GbE. We have different guests (all Ubuntu releases, 13.04 and 13.10), and they all seem to be affected. Clocksource: kvm-clock on all guests. Clock entry from the guest XML: <clock offset='utc'/> Now as far as I've read in the documentation of kvm-clock, it specifically supports live migrations, so I'm a bit surprised at these problems. There isn't all that much information to find on these issue, although I have found postings by others that seem to have run into the same issues, but without a solution. Any help would be much appreciated. Regards, Paul Boven. -- Paul Boven <boven(a)jive.nl> +31 (0)521-596547 Unix/Linux/Networking specialist Joint Institute for VLBI in Europe - www.jive.nl VLBI - It's a fringe science

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[libvirt-users] io mode=native precisions
by Raphael Bauduin 24 Mar '14

24 Mar '14

Hi, Before switching to io mode=native, I wanted to check if there are any disadvantages or potential problem with this setting. I virtio-blk data plane required to use this setting effectively? (as illustrated here: http://blog.vmsplice.net/2013/03/new-in-qemu-14-high-performance-virtio.html) Is there a requirement on the host kernel (eg minimum version)? Thanks in advance Raph

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[libvirt-users] can I undo the snapshot apply of a qcow2 image
by lyz_pro 24 Mar '14

24 Mar '14

Hi all I have a problem. Two days ago , I used kvm-img create a snapshot of an qcow2 format image. And today I apply the snapshot of this image. The question is can I recovery the image to the last point . I mean Undo this snapshot apply -------------- lyz_pro 2014-03-24

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[libvirt-users] Issues to manage RAM on openvz guests
by Aurelien Martin 23 Mar '14

23 Mar '14

Hi all, I'm playing with virsh, and I succeed to mange easily some KVM nodes. But I have issues to size RAM of openvz guests. virsh set by default the the memory to 256M on each guest instead of that I specify in the XML I have to modify by end the variable PHYSPAGES on each /etc/vz/conf/id_of_my_vz.conf Please follow the XML dump and the steps that I did. Cheers,Aurelien Log ---- 1) Define openvz guest domain 103 #virsh -c openvz:///system define vztest.xml Domain 103 defined from vztest.xml 2) Start the guest #virsh -c openvz:///system start 103 Domain 103 started #vzlist CTID NPROC STATUS IP_ADDR HOSTNAME 103 20 running - - 3) Check memory size vz guest 103 #vzctl enter 103 entered into CT 103 #root@test:/# free -m total used free shared buffers cached Mem: 256 27 228 0 0 14 -/+ buffers/cache: 13 242 Swap: 512 0 512 vztest.xml ----------- <domain type='openvz'> <name>100</name> <uuid>86c12009-e591-a159-6e9f-91d18b85ef78</uuid> <memory unit='GiB'>1</memory> <currentMemory unit='GiB'>1</currentMemory> <vcpu placement='static'>1</vcpu> <os> <type>exe</type> <init>/sbin/init</init> </os> <devices> <filesystem type='template' accessmode='passthrough'> <source name='debian-7.0-x86_64'/> <target dir='/'/> </filesystem> <interface type='bridge'> <mac address='00:16:3e:1a:66:67'/> <source bridge='br0'/> <target dev='veth3'/> </interface> </devices> </domain> xmldump -------- <domain type='openvz' id='103'> <name>103</name> <uuid>86c52009-e541-a159-6e9f-91d18b85ef79</uuid> <memory unit='KiB'>0</memory> <currentMemory unit='KiB'>0</currentMemory> <vcpu placement='static'>1</vcpu> <os> <type>exe</type> <init>/sbin/init</init> </os> <clock offset='utc'/> <on_poweroff>destroy</on_poweroff> <on_reboot>destroy</on_reboot> <on_crash>destroy</on_crash> <devices> <filesystem type='template' accessmode='passthrough'> <source name='debian-7.0-x86_64'/> <target dir='/'/> </filesystem> <interface type='bridge'> <mac address='00:16:3e:1a:66:67'/> <source bridge='br0'/> <target dev='veth3'/> </interface> </devices> </domain>

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[libvirt-users] Live migration process in src/qemu_driver.ca
by Faizul Bari 21 Mar '14

21 Mar '14

Hello, I have been trying to track different phases of a live migration process. I am using libvirt with qemu-kvm. I am issuing migration commands using virsh. Now, I want to measure the time spent in each phase of live migration, e.g., pre-copy and stop-copy. I stumbled upon the file qemu_driver.c. It has functions like qemudDomainMigratePrepare2 qemudDomainMigratePerform qemudDomainMigrateFinish2 I want to know whether qemudDomainMigratePerform and qemudDomainMigrateFinish2 directly map to the pre-copy and stop-copy phase? or the qemudDomainMigratePerform function performs both of them? Any pointers or suggestions will be greatly appreciated. Regards ---------------------- Md. Faizul Bari PhD Student David R. Cheriton School of Computer Science University of Waterloo {http://www.cs.uwaterloo.ca/~mfbari} [My mind rebels at stagnation! Give me problems! Give me work!]

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[libvirt-users] Linux host / Windows guest sharing
by Pal, Laszlo 21 Mar '14

21 Mar '14

Hi, I'm almost give up again because for a day I try to access my windows kvm guest from FC20 :) I've tried everything including virtio mapping mount -t 9p -o trans=virtio,version=9p2000.L hostshare /tmp/hostfiles where I get the following messages mount: special device hostshare does not exist --- --- to be honest clipboard sharing would be enough for me, so I googled why it is not working and I applied this: https://mytechdepot.wordpress.com/2013/02/22/enabling-clipboard-copy-paste-… yum install spice-vdagent # chkconfig --add spice-vdagentd # service spice-vdagentd start but, the clipboard sharing isn't working.... Do you have any idea to solve any of the issues above? Thank you Vlad

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[libvirt-users] Adjust disk image migration (NBD)
by Joaquim Barrera 20 Mar '14

20 Mar '14

Hi all, As I am doing some tests with qemu, I realized that the way it does 'migrate -i tcp:DEST:444' is not the same as 'libvirt migrate --copy-storage-inc'. Basically qemu uses the same stream as RAM migration and libvirt takes advantage of NBD transfer. With virsh migrate-setspeed I observed that one can only control the transfer throughput of RAM, but not disk synchronization. At least this is what I can see in bmon when doing a migration with incremental copy. The question is: Am I missing something or it is not implemented? Thank you guys!

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[libvirt-users] KVM networking help needed - Promiscuous network configuration for guest Snort instance
by Philip Wang 19 Mar '14

19 Mar '14

Hi, I am looking for some direction on how to configure KVM networking so that a promiscuous bridge/host nic/guest nic allows two different network monitoring packages to sniff the same physical traffic. The idea is to run a commercial package on the CentOS 6.5 host and Snort, via Security Onion, on the guest, both being fed by a physical switch SPAN or physical firewall TAP. The host has two NICs, one for management and one for sniffing. I am using libvirt and libvirt-manager to supplement configuration. I have basic bridge networking configured and connected on the management NIC, but I can't seem to figure out the missing piece for getting physical network traffic from the SPAN/TAP port to the Xubuntu guest NIC for sniffing. I have seen mention of setting the bridge aging time to 0, but that did not seem to work and the only place I could find to verify the setting was by running brctl showmacs <brisge name>. I have also seen posts saying this was more of a workaround, without discussing an alternate method. I have tinkered with setting the host nic, bridge, and guest nic to promiscuous mode, only to see relatively equal traffic climb on the host nic and bridge, but not the guest nic. Other searched have turned up discussions about tunctl and its implementation, so at this point I figured a reality check was in order. Is this idea feasible? If so, where should I be looking for information on how to implement it? Thanks in advance for any pointers.

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[libvirt-users] Working Set Size Estimation
by Giampiero De Ciantis 18 Mar '14

18 Mar '14

Is there a way through virsh or libvirt to get the working set size for a VM. I am trying to find a metric similar to what VMware calls "Active Memory". Thanks in advance, -Gp

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