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[libvirt-users] virsh not detecting hugepage mount; disabled by config?
by Manuel Ullmann 14 Dec '16

14 Dec '16

Hi, I’m struggling with virsh not detecting my hugepage mount. I have the following kernel command line: BOOT_IMAGE=/vmlinuz-4.8.13-gentoo root=/dev/mapper/gensd-gentoo ro quiet splash intel_iommu=on video=efifb:off,vesafb:off,simplefb:off splash=verbose,theme:livedvd-aurora kvm.ignore_msrs=1 transparent_hugepage=never hugepages=3072 softlevel=qemuvm My startup script outputs the following: hugetlbfs /var/lib/hugetlbfs hugetlbfs rw,relatime,pagesize=2097152,uid=77,gid=77,mode=0770 0 0 [2016.12.13 22:22:50 virsh 2808] ERROR Failed to start domain win10 [2016.12.13 22:22:50 virsh 2808] ERROR internal error: hugetlbfs filesystem is not mounted or disabled by administrator config virsh was unsuccessful So hugetlbfs is definitively mounted, but virsh does either not detect it or some magical option, that I’ve not found in a day searching for it, disables it (the documentation could explain that better). Since the Ubuntu guys refer to the KVM_HUGEPAGES environment, I tried adding it to start-stop-daemon environment, but it seems non-relevant. 77 is the qemu user id, but I’m quite sure the permission issues were excluded (tried root permissions as well). Besides I had permission errors occasionally occasionally and don’t have them anymore. If you could provide a hint to the magical administrator configuration option, that would be helpful. Tried hugeadm as well, pointing the config to the correct destination. Thanks in advance, Manuel PS: The virsh script reads like this: #!/bin/sh cmdline="$(cat /proc/cmdline)" if [[ "${cmdline##* }" == "softlevel=qemuvm" ]]; then mount -o rw,relatime,pagesize=2097152,uid=77,gid=77,mode=0770 -t hugetlbfs hugetlbfs /var/lib/hugetlbfs sysctl kernel.shmmax=6442450944 cat /proc/mounts | grep hugetlb >> /var/log/virsh.log sed -i -e '/^hugetlb/{s/^/\#/}' /etc/libvirt/qemu.conf counter=0 while [ "${counter}" -lt 10 && ! -S /var/run/libvirt/libvirt-sock ]; do sleep 1 counter=$(( ++counter )) done if [ $counter -gt 9 ]; then echo "libvirtd socket generation timed out" >> /var/log/virsh.log fi if pidof libvirtd &>/dev/null; then LC_ALL=C /usr/bin/virsh -l /var/log/virsh.log start win10 if [ $? -gt 0 ]; then echo "virsh was unsuccessful" >> /var/log/virsh.log reboot fi else echo "libvirtd is not started" >> /var/log/virsh.log reboot fi fi reboot is more convenient, since this is a vfio-igd passthrough vm.

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[libvirt-users] Kernel panic after kernel update
by Michael Ströder 07 Dec '16

07 Dec '16

HI! On one qemu-kvm instance a kernel update failed and booting the image is not possible anymore (see below). A dozen other VMs are correctly working after the upgrade. Anything I can quickly try to make it work again? (This is not really a bad emergency case because I could simply re-install and re-configure with ansible. But I'd like to learn about these cases...) Ciao, Michael. Loading Linux 4.8.12-1-default ... [ 0.651328] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) [ 0.654408] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.8.12-1-default #1 [ 0.656941] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014 [ 0.661166] 0000000000000000 ffffffff813a4252 ffff9a5348c4d000 ffff9a5349957e60 [ 0.664652] ffffffff8118e3fa ffff9a5300000010 ffff9a5349957e70 ffff9a5349957e08 [ 0.668124] ffffffff8118e715 ffff9a5349957e78 0000000000000001 0000000000000000 [ 0.671457] Call Trace: [ 0.672460] [<ffffffff8102eefe>] dump_trace+0x5e/0x310 [ 0.674389] [<ffffffff8102f2cb>] show_stack_log_lvl+0x11b/0x1a0 [ 0.676570] [<ffffffff81030001>] show_stack+0x21/0x40 [ 0.678480] [<ffffffff813a4252>] dump_stack+0x5c/0x7a [ 0.680369] [<ffffffff8118e3fa>] panic+0xd5/0x217 [ 0.682169] [<ffffffff81f56419>] mount_block_root+0x1fe/0x2c0 [ 0.684285] [<ffffffff81f56668>] prepare_namespace+0x12b/0x161 [ 0.686439] [<ffffffff81f56103>] kernel_init_freeable+0x1f6/0x20a [ 0.688675] [<ffffffff816c727a>] kernel_init+0xa/0x100 [ 0.690623] [<ffffffff816d485f>] ret_from_fork+0x1f/0x40 [ 0.696659] DWARF2 unwinder stuck at ret_from_fork+0x1f/0x40 [ 0.698858] [ 0.699533] Leftover inexact backtrace: [ 0.699533] [ 0.701580] [<ffffffff816c7270>] ? rest_init+0x90/0x90 [ 0.703944] Kernel Offset: 0x0 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)

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[libvirt-users] How to best I/O performance for Window2008 and MSSQL guest VM
by Roberto Fichera 07 Dec '16

07 Dec '16

Hi There, I've moved some Windows2012 with MSSQL VMs from an hold ESXi 5.5 machine to a more recent and powerful machine running Fedora 24 x86_64 and related libvirt + KVM virtualization. I've moved the VMs filesystem to LVM slices and installed the VirtIO drivers in to all Windows VMs. I've also set both Disk and Network interface to work using VirtIO. So far so good everything works pretty fine. Now I would like to tune at best the MSSQL VM for both Disk and Network interfaces in order to get the best performance possible. Regarding network interface I've set it to work as bridge instead to go through to macvtap, so I'm not sure what is the best in this case. Regarding disk, since it's LVM I've chosen to go to cache mode none and IO mode native. Also here cannot judge what's the best setup for the workload. I'm undecided to use IO mode threads along directsync cache mode. Finally I've set "ionice -c 1 -p <qemu-pid> -n 0" and "renice -n -10 <qemu-pid>" for the interested VM that I want to get best performance possible. Even with the above setup, the MSSQL VM has performance similar to the old machine running ESXi 5.5, so does anyone can suggest where too look at and/or what would be the right setup? Thanks in advance. Roberto Fichera

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[libvirt-users] How can openstack retrieve the CPU usage of a lxc via libvirt?
by WANG Cheng D 06 Dec '16

06 Dec '16

Dear all, I want to have a view of lxc CPU usage in openstack Dashboard. According the Openstack official site , Openstack Ceilometer can poll libvirt daemon to obtain CPU usage of a virtual machine. I tried the command locally on the libvirtd host "virsh -c lxc:/// domjobinfo", I got an error "error: this function is not supported by the connection driver: virDomainGetJobInfo" I am not sure if Openstack Ceilometer can retrieve the CPU usage of a linux container, if it can, which virsh command or API should be used to this? Thank you for your response in advance. Cheng

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[libvirt-users] Understanding and converting between type='drive' and type='pci'
by Leroy Tennison 02 Dec '16

02 Dec '16

First, if this isn't the right list please tell me where i should post. I've searched for an explanation and I'm either searching for the wrong thing or it's not there. I'm trying to get an understanding of the "controller='0' bus='0' target='0' unit='0' " parameters for 'drive' compared to the "domain='0x0000' bus='0x00' slot='0x05' function='0x0' " parameters for 'pci'. It appears that 'dev hda' to 'dev hdd' is the maximum associated with 'drive', how many are available with 'pci' and what are the valid ranges for those parameters? If I have an xml using 'drive' and want to convert it to 'pci' what do I need to do? I've had trouble with this when moving disk images between hypervisors but have never had the time to investigate fully, does it have to do with how the drives are referenced (/dev/disk/by0id or /dev/[h|s|v]da as opposed to UUID)? Thanks for your help.

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[libvirt-users] sudo user to access xen server remotely.
by ganesh kg 29 Nov '16

29 Nov '16

HI, i am trying to use sudo user to access xen server remotely. As its documented, libvirtd can be accessed only through root user or users from libvirtd usergroup. is there any tweak or possibility to access libvirt remotely through sudo user? or by using certificate? code snippet: #!/usr/bin/env python import sys import libvirt conn = libvirt.open('xen+ssh://sudo_user@xen_server') <== Trying to establish connection to the remote xen using sudo user. if conn == None: print('Failed to open connection to xen+ssh:xen_server') exit(1) host = conn.getHostname() print('Hostname:'+host) conn.close() exit(0)

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[libvirt-users] Routed mode problem with SSH
by Marcelo Palma 28 Nov '16

28 Nov '16

Hi guys, I describe the context of the problem below: I installed a Tor relay on a virtual machine on my server with IP 9.1.1.101. This virtual machine needs to use a static IP (9.1.1.102) to work as a Tor relay. After that I create a virtual network in *Routed mode* to connect to the physical network (used as a bridge between the virtual machine and the external network (Internet)). Since I change the NAT to Routed mode, I can't access my server via ssh user(a)9.1.1.101. Will it be a Routed mode problem? How can I solve this problem? Thank you Marcelo

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[libvirt-users] stream finish throws exception via python API
by Shahar Havivi 28 Nov '16

28 Nov '16

Hi, The following snippet works fine e.g. receiving the data but when calling stream.finish() we get the following error: stream = con.newStream() vol.download(stream, 0, 0, 0) buf = stream.recv(1024) stream.finish() libvirt: I/O Stream Utils error : internal error: I/O helper exited abnormally Traceback (most recent call last): File "./helpers/kvm2ovirt", line 149, in <module> download_volume(vol, item[1], diskno, disksitems, pksize) File "./helpers/kvm2ovirt", line 102, in download_volume stream.finish() File "/usr/lib64/python2.7/site-packages/libvirt.py", line 5501, in finish if ret == -1: raise libvirtError ('virStreamFinish() failed') libvirt.libvirtError: internal error: I/O helper exited abnormally Am I doing something wrong? Thank you, Shahar.

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[libvirt-users] locking domain memory
by Dennis Jacobfeuerborn 27 Nov '16

27 Nov '16

Hi, is there a way to lock a guests memory so it doesn't get swapped out? I now there is memoryBacking->locked but that says it requires memtune->hard_limit and the description of that basically "don't ever do this" rendering the locked element kind of pointless. How can I prevent the guests memory from being swapped out without shooting myself in the foot? Regards, Dennis

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[libvirt-users] NUMA VM and assigning interfaces
by Amir Shehata 26 Nov '16

26 Nov '16

Hello, Hope all is well. I've been looking at how I can create a virtual machine which is NUMA capable. I was able to do that by: 140 <qemu:commandline> 143 <qemu:arg value='-numa'/> 144 <qemu:arg value='node'/> 145 <qemu:arg value='-numa'/> 146 <qemu:arg value='node'/> 147 </qemu:commandline> This creates two NUMA nodes. Now I would like to assign my virtual network interfaces, of which I have three, to the different NUMA nodes on the VM. Anyone know how I can do that? Any help/pointers would be much appreciated. I'm trying to create a VM that will enable me to test a NUMA based feature. thanks amir

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