- Users - libvirt List Archives

[libvirt-users] Guest Reboot After Plug HDMI
by Lying 04 Dec '17

04 Dec '17

Hello, Everybody. I encounter a problem when i using my guest. I booting my guest without HDMI primarily, Then i add it, but my guest is be rebooted. To know what cause it, i do it again, especially i check my guest is running normal or not with "ping" before plugging, that's well. What i was suffer? can you help me solve it? Following message is detailed!!! Guest: window 7 profession Linux: Ubuntu 1604 Qemu:1 v2.11.0-rc0 Libvirt: 3.9 method of booting: virsh start myGuest1 method of plug HDMI: virsh qemu-monitor-command myGuest1 --hmp 'device_add driver=vfio-pci,host=01:00.0,xvga=on,multifunction=yes' phenomenon: after plugging, my Guest is failed to check with "ping", for a while, my display is light and load windows. expect: my guest is running when i plug HDMI, it seem that hot add a device.

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[libvirt-users] vga passthroufh fail
by Lying 28 Nov '17

28 Nov '17

Hello, I encounter a problem, my display is not light when guest running. But it's successful that i check guest with command "ping". Following message is my xml and refer topic from https://libvirt.org/formatdomain.html#elementsHostDev: <hostdev mode='subsystem' type='pci' managed='yes'> <driver name='vfio' /> <source> <address domain='0x0000' bus='0x06' slot='0x02' function='0x0'/> </source> </hostdev>

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[libvirt-users] Export Video on Graphics Card
by Lying 21 Nov '17

21 Nov '17

I have two graphics card on my machine And i want to export my video on one card when VM switched on What should i do?

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[libvirt-users] virtlock - a VM goes read-only
by Branimir Pejakovic 20 Nov '17

20 Nov '17

Dear colleagues, I am facing a problem that has been troubling me for last week and a half. Please if you are able to help or offer some guidance. I have a non-prod POC environment with 2 CentOS7 fully updated hypervisors and an NFS filer that serves as a VM image storage. The overall environment works exceptionally well. However, starting a few weeks ago I have been trying to implement virtlock in order to prevent a VM running on 2 hypervisors at the same time. Here is the description how the environment looks like in terms of virtlock configuration on both hypervisors: -- Content of /etc/libvirt/qemu.conf -- lock_manager = "lockd" Only the above line is uncommented for direct locking. # libvirtd --version; python -c "import platform; print(platform.platform())"; virtlockd -V libvirtd (libvirt) 3.2.0 Linux-3.10.0-693.2.2.el7.x86_64-x86_64-with-centos-7.4.1708-Core virtlockd (libvirt) 3.2.0 # getenforce Permissive Here is the issue: h1 # virsh list Id Name State ---------------------------------------------------- 1 test09 running h1 # virsh domblklist test09 Target Source ------------------------------------------------ vda /storage_nfs/images_001/test09.qcow2 h1 # h2 # virsh list Id Name State ---------------------------------------------------- h2 # virsh list --all | grep test09 - test09 shut off h2 # virsh start test09 error: Failed to start domain test09 error: resource busy: Lockspace resource '/storage_nfs/images_001/test09.qcow2' is locked h2 # virsh list Id Name State ---------------------------------------------------- h2 # Before I start test09 I open a console to the guest and observe what is going on in it. Once I try to start test09 (and get a message about locked resource) on h2 hypervisor, I can see the following messages in the console and the vm goes to ro mode: on test09's console: [ 567.394148] blk_update_request: I/O error, dev vda, sector 13296056 [ 567.395883] blk_update_request: I/O error, dev vda, sector 13296056 [ 572.871905] blk_update_request: I/O error, dev vda, sector 8654040 [ 572.872627] Aborting journal on device vda1-8. [ 572.873978] blk_update_request: I/O error, dev vda, sector 8652800 [ 572.874707] Buffer I/O error on dev vda1, logical block 1081344, lost sync page write [ 572.875472] blk_update_request: I/O error, dev vda, sector 2048 [ 572.876009] Buffer I/O error on dev vda1, logical block 0, lost sync page write [ 572.876727] EXT4-fs error (device vda1): ext4_journal_check_start:56: Detected aborted journal[ 572.878061] JBD2: Error -5 detected when updating journal superblock for vda1-8. [ 572.878807] EXT4-fs (vda1): Remounting filesystem read-only [ 572.879311] EXT4-fs (vda1): previous I/O error to superblock detected [ 572.880937] blk_update_request: I/O error, dev vda, sector 2048 [ 572.881538] Buffer I/O error on dev vda1, logical block 0, lost sync page write I also observe the guests'log: -- /var/log/libvirt/qemu/test09.log -- block I/O error in device 'drive-virtio-disk0': Permission denied (13) block I/O error in device 'drive-virtio-disk0': Permission denied (13) block I/O error in device 'drive-virtio-disk0': Permission denied (13) block I/O error in device 'drive-virtio-disk0': Permission denied (13) block I/O error in device 'drive-virtio-disk0': Permission denied (13) block I/O error in device 'drive-virtio-disk0': Permission denied (13) block I/O error in device 'drive-virtio-disk0': Permission denied (13) If it helps, here is the disk portion of an XML file: <disk type='file' device='disk'> <driver name='qemu' type='qcow2' cache='none'/> <source file='/storage_nfs/images_001/test09.qcow2'/> <backingStore/> <target dev='vda' bus='virtio'/> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/> </disk> I usually do implement SELinux on a hypervisor to isolate guests even further but this time I set it to permissive mode just to rule out SELinux factor. The same thing happens when SELinux is in enforcing mode (virt_use_nfs is set to on in that case) and audit2why doesn't report any anomalies when parsing audit logs. I have tried to use indirect locking via the same filer and with a separated export for the hashes by removing the comment in /etc/libvirt/qemu-lockd.conf for the following line: file_lockspace_dir = "/var/lib/libvirt/lockd/files" In this case the hashes are normally created on the NFS export mounted under /var/lib/libvirt/lockd/files. I have also tried playing with both QCOW2 and raw disk images for VMs (and even with XFS/ext4 based guests) but the outcome is always the same. I have a couple of KVM books - consulted them on this topic, consulted Red Hat and SUSE docs but pretty much the configuration instructions are, naturally, the same. I saw that some colleagues posted a few emails (ie https://www.redhat.com/archives/libvirt-users/2015-September/msg00004.html) to the list related to virtlock but it seems that it is not the same issue. I have also, as a last resort, completely disabled SELinux, rebooted both hypervisors, created a new vm, repeated all the steps listed above but with the same results. Now, I am pretty sure that I am missing something simple here since this is a standard feature and should work out of the box if set correctly but so far I cannot see what I am missing. I would really appreciate any tip/help. Thank you very much!! Regards, Branimir

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[libvirt-users] Does libvirt-sanlock support network disk?
by Han Han 20 Nov '17

20 Nov '17

Hello, As we know, libvirt sanlock support file type storage. I wonder *if it supports network storage.* I tried *iSCSI*, but found it didn't generate any resource file: Version: *qemu-2.10 libvirt-3.9 sanlock-3.5* 1. Set configuration: qemu.conf: *lock_manager = "sanlock"* qemu-sanlock.conf: *auto_disk_leases = 1disk_lease_dir = "/var/lib/libvirt/sanlock"host_id = 1user = "sanlock"group = "sanlock"* # systemctl restart sanlock # systemctl restart libvirtd 2. Start a VM with iSCSI disk and check *resource file* VM disk xml: <disk type='network' device='disk'> <driver name='qemu' type='raw'/> <source protocol='iscsi' name='iqn.2003-01.org.linux-iscsi.localhost.x8664:sn.cb4bfb00df2f/0'> <host name='xx.xx.xx.xx' port='3260'/> </source> <target dev='vda' bus='virtio'/> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/> </disk> Start VM: # virsh start iscsi Domain iscsi started Check resource file: # ls /var/lib/libvirt/sanlock __LIBVIRT__DISKS__ No resource file generated. So, does libvirt sanlock only support file or block type storage? -- Han Han Quality Engineer Redhat. Email: hhan(a)redhat.com Phone: +861065339333

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[libvirt-users] Urgent: virsh - change-media run into a promptly close of libvirt
by Holger Schranz 15 Nov '17

15 Nov '17

Hello, I use the virsh change-media command and since the combination of: etcsvms5:/kvm/CS8400/M1 # virsh version Compiled against library: libvirt 3.9.0 Using library: libvirt 3.9.0 Using API: QEMU 3.9.0 Running hypervisor: QEMU 2.10.1 etcsvms5:/kvm/CS8400/M1 # I got the following problem: ---------------------- etcsvms5:/kvm/CS8400/M1 # virsh change-media S5VCS84M1-VLP0 hdc --eject Successfully ejected media. etcsvms5:/kvm/CS8400/M1 # virsh change-media S5VCS84M1-VLP0 hdc /home/kvm/etcsdvmb/Medien/V7.0A/CS_licenses/key-cd_VCS85FTSVTL.iso --insert error: Disconnected from qemu:///system due to end of file error: Failed to complete action insert on media error: End of file while reading data: Input/output error ---------------------- journalctl -b | less shows the following: Nov 14 10:11:32 etcsvms5 kernel: libvirtd[10178]: segfault at 10 ip 00007f49ff969170 sp 00007f4a069cb940 error 4 in libvirt_driver_qemu.so[7f49ff8d9000+172000] Nov 14 10:11:37 etcsvms5 systemd-coredump[42152]: Process 10177 (libvirtd) of user 0 dumped core. ---------------------- At the end all open consoles of all virtual machines closed and the virt-manager also. A restart of the libvirtd is possible but not helpful The virsh change-media commands are in procedure andused since a long time. I need the change-media function at the installation of our test systems. Therefor I need an urgent help please Best regards Holger --- Diese E-Mail wurde von Avast Antivirus-Software auf Viren geprüft. https://www.avast.com/antivirus

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[libvirt-users] Issues on hibernated domains
by Francesc Guasch 15 Nov '17

15 Nov '17

Hello. I am using libvirt and KVM for a VDI project. It works fine, great job ! I have only a small issue that bothers some users from time to time. This is libvirt-bin 2.5.0-3ubuntu5.5. When restoring a saved domain that has been many hours or days down, the network address may be taken by some other virtual machine. Then both are in conflict. I found this patch: https://www.redhat.com/archives/libvir-list/2016-October/msg00561.html And I tried setting it in my host but it discards silently my settings after doing virsh net-edit. So It may not be apllied to the 2.5.0 release ? That's what I tried: <dhcp> <leasetime>24h</leasetime> <range start='192.168.122.2' end='192.168.122.254'/> </dhcp> I also tried leasetime -1 with the same results. I also found about adding infinite to the dhcp-range at /var/lib/libvirt/dnsmasq/default.conf. But this file has a comment about it shouldn't be edited and it should be done with net-edit. But I don't know how to add this tag to the network. dhcp-range=192.168.122.2,192.168.122.254,infinite Any hints ? Thank you for your time. -- Francesc Guasch ETSETB - UPC

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[libvirt-users] dramatic performance slowdown due to THP allocation failure with full pagecache
by Blair Bethwaite 15 Nov '17

15 Nov '17

Hi all, This is not really a libvirt issue but I'm hoping some of the smart folks here will know more about this problem... We have noticed when running some HPC applications on our OpenStack (libvirt+KVM) cloud that the same application occasionally performs much worse (4-5x slowdown) than normal. We can reproduce this quite easily by filling pagecache (i.e. dd-ing a single large file to /dev/null) before running the application. The problem seems to be that the kernel is not freeing (or has some trouble freeing) the non-dirty and (presumably immediately) reclaimable pagecache in order to allocate THPs for the application. This behaviour is also observable on regular bare-metal, but the slowdown is only 10-20% there - the nested paging of the guest really makes THP allocation important there (1). Both current CentOS and Ubuntu guests have the issue. Some more environmental context: the VMs are tuned (CPU pinning, NUMA topology, hugepage backing), so we normally see no difference between host and guest performance. After talking to many other colleagues in the HPC space it seems common that people setup their batch schedulers to put drop_caches between jobs, which can help to workaround this and other similar issues, but no-one has been able to explain why this is happening. Hopefully someone who knows about the guts of the Linux MM can shed some light...? (1) a related and possibly dumb question: in the case of a high-performance KVM where the guest is hugepage backed and pinned in host memory anyway, why do we still have a table based resolution for guest physical to host virtual address translation - couldn't this just be done by offset? -- Cheers, ~Blairo

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[libvirt-users] Help：Can libvirt restore several xen snapshots more faster at same time?
by Chenjia (C) 14 Nov '17

14 Nov '17

Dear libvirt expert, we find a blocker issue in our project. Would you please offer us some feedback? Our project have a requirement: restore as much as xen snapshot at same time. we have done the following test(our environment is cpu E52620, 256G memory, SSD hard disk. The xen snapshot is Win7 OS with 1G memory): 1) Save 40 xen snapshots to disk, then restore these snapshot at sametime, we found the restore speed is too slow, and the bottleneck is the IO speed. 2) we save all the 40 xen snapshot to ramdisk, then we got a good performance, but the space is too big, about 40G, it is too expensive . Our question is : 1) each our xen snapshot is almost same except IP address(Win7 OS with 1G memory), does there have some way to reduce the 40 snapshots space? (we find the ‘virsh resotre’ cmd have an argument ‘�xml’ , but it seems not work in source code) 2) Do you have some suggestion to improve the performance of restore as much as xen snapshot at same time? Best regards, wish your reply.

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[libvirt-users] KVM guest incorrect CPU frequency
by xmbbb 13 Nov '17

13 Nov '17

Hello, I am facing an issue where the detected CPU frequencies in KVM guests are incorrect. I am using the new Core i9 7900x with base clock 3.3GHz with "host-passthrough". Both Win10 and Linux guests incorrectly detect 3.45GHz for some reason. The workaround I have found is to temporarily switch to use HPET clocksource in the HOST before starting the VM. This makes the VMs correctly detect a 3.3GHz CPU. Then I can safely switch back to TSC in the VM HOST. This mostly does not impact much for day to day use. The only reproducible bug I can find with an incorrect CPU frequency is playing Bink videos that come with PC games. If I play any Bink video cut scene from the 2013 Tomb Raider game with the incorrect CPU frequency, the video plays a little slower than intended which results in audio cut out once in a while so that the video can "catch up" to the audio. Anyone having experiences with similar issues?

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