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[libvirt-users] surprising <backingStore type='file'> setting in domain.xml
by Thomas Stein 17 May '19

17 May '19

Hello all. My currently used versions: libvirt-5.2.0 and qemu-4.0.0. Here is my problem. I'm struggeling since a few weeks with a strange behaviour by either qemu or libvirt. After a reboot of the hardware node the $domain.xml contains suddenly a backingStore setting which was not there before reboot. Something like that: <devices> <emulator>/usr/bin/qemu-system-x86_64</emulator> <disk type='file' device='disk'> <driver name='qemu' type='qcow2'/> <source file='/var/lib/libvirt/shinymail/shinymail_weekly.qcow2-2019-05-15'/> <backingStore type='file'> <format type='qcow2'/> <source file='/var/lib/libvirt/images/shinymail.qcow2'/> </backingStore> <target dev='vda' bus='virtio'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/> </disk> ... This obviousely happens after a backup has been running. The Backup Script looks like this: <snip> virsh snapshot-create-as --domain shinymail weekly --diskspec vda,file=/var/lib/libvirt/shinymail/shinymail_weekly.qcow2-$(date +%Y-%m-%d) --disk-only --atomic --no-metadata cp ... virsh blockcommit shinymail vda --active --verbose --pivot <snip> So after that "dmblklist shinymail" does show the right source file but after a reboot it tries to use the weekly snapshot again which leads to filesystem errors. Someone has an idea what could cause such a behaviour? cheers t. -- libvir-list mailing list libvir-list(a)redhat.com https://www.redhat.com/mailman/listinfo/libvir-list

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[libvirt-users] domain still running although snapshot-file is deleted !?!
by Lentes, Bernd 15 May '19

15 May '19

Hi, i have a strange situation: A domain is still running where domblklist points to a snapshot file and also dumpxml says the current drive is that snapshot file. But the file has been deleted hours ago. And the domain is still running. I can login via ssh, the database and the webserver are still running, domain is performant. How can that be ? Also lsof shows that the file is deleted: qemu-syst 27007 qemu 15ur REG 254,14 335609856 183599 /mnt/snap/sim.sn (deleted) qemu-syst 27007 qemu 16ur REG 254,14 335609856 183599 /mnt/snap/sim.sn (deleted) qemu-syst 27007 27288 qemu 15ur REG 254,14 335609856 183599 /mnt/snap/sim.sn (deleted) qemu-syst 27007 27288 qemu 16ur REG 254,14 335609856 183599 /mnt/snap/sim.sn (deleted) CPU\x200/ 27007 27308 qemu 15ur REG 254,14 335609856 183599 /mnt/snap/sim.sn (deleted) CPU\x200/ 27007 27308 qemu 16ur REG 254,14 335609856 183599 /mnt/snap/sim.sn (deleted) CPU\x201/ 27007 27309 qemu 15ur REG 254,14 335609856 183599 /mnt/snap/sim.sn (deleted) CPU\x201/ 27007 27309 qemu 16ur REG 254,14 335609856 183599 /mnt/snap/sim.sn (deleted) vnc_worke 27007 27321 qemu 15ur REG 254,14 335609856 183599 /mnt/snap/sim.sn (deleted) vnc_worke 27007 27321 qemu 16ur REG 254,14 335609856 183599 /mnt/snap/sim.sn (deleted) Bernd -- Bernd Lentes Systemadministration Institut für Entwicklungsgenetik Gebäude 35.34 - Raum 208 HelmholtzZentrum münchen bernd.lentes(a)helmholtz-muenchen.de phone: +49 89 3187 1241 phone: +49 89 3187 3827 fax: +49 89 3187 2294 http://www.helmholtz-muenchen.de/idg wer Fehler macht kann etwas lernen wer nichts macht kann auch nichts lernen Helmholtz Zentrum Muenchen Deutsches Forschungszentrum fuer Gesundheit und Umwelt (GmbH) Ingolstaedter Landstr. 1 85764 Neuherberg www.helmholtz-muenchen.de Stellv. Aufsichtsratsvorsitzender: MinDirig. Dr. Manfred Wolter Geschaeftsfuehrung: Prof. Dr. med. Dr. h.c. Matthias Tschoep, Heinrich Bassler, Kerstin Guenther Registergericht: Amtsgericht Muenchen HRB 6466 USt-IdNr: DE 129521671

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[libvirt-users] domains paused without any obvious reason
by Lentes, Bernd 15 May '19

15 May '19

Hi, i have a two node HA-Cluster with several domains as resources. Currently it's running in test mode. Some domains (all on the same host) stopped running, virsh list shows them as "paused". All stopped at the same time (11th of may, 7:00 am), my monitoring system began to yell. I don't have any clue why this happened. virsh domblkerror says for all the domains (5) "no space". The days before the domains were running fine and i know that all disks inside the domain should have enough space. Also the host is not running out of space. The logs don't say anything sensefully, unfortunately i didn't have a log for the libvirtd daemon, i just configured that now. The domains are stopped each day by cron at 10:30 pm for a short moment, a snapshot is taken, domains are started again, the backing file is copied to a CIFS server and if that is finished the snapshot is blockcommited into the backing file. That's working fine already for several days. This cronjob creates a log and it's looking fine. The domains reside in naked Logical Volumes, the respective Volume Group has enough space. Bernd -- Bernd Lentes Systemadministration Institut für Entwicklungsgenetik Gebäude 35.34 - Raum 208 HelmholtzZentrum münchen bernd.lentes(a)helmholtz-muenchen.de phone: +49 89 3187 1241 phone: +49 89 3187 3827 fax: +49 89 3187 2294 http://www.helmholtz-muenchen.de/idg wer Fehler macht kann etwas lernen wer nichts macht kann auch nichts lernen Helmholtz Zentrum Muenchen Deutsches Forschungszentrum fuer Gesundheit und Umwelt (GmbH) Ingolstaedter Landstr. 1 85764 Neuherberg www.helmholtz-muenchen.de Stellv. Aufsichtsratsvorsitzender: MinDirig. Dr. Manfred Wolter Geschaeftsfuehrung: Prof. Dr. med. Dr. h.c. Matthias Tschoep, Heinrich Bassler, Kerstin Guenther Registergericht: Amtsgericht Muenchen HRB 6466 USt-IdNr: DE 129521671

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[libvirt-users] VM display is blank when open (but Gnome Boxes thumbnails ok)
by Michel Rozpendowski 14 May '19

14 May '19

Hi, I also posted this question on the IRC #virt channel but have not received any reaction at the moment of posting this message to the mailing list. Since I last turned off my laptop (Dell XPS-15-9570 running Ubuntu 19.04) on Friday 10 May (I had to do it by long power press by the way), I am no longer able to get the display of my VMs: I am getting a black screen, even though I can see it running in the thumbnail of Gnome Boxes. You can see the described behaviour on the following video capture: https://youtu.be/Lv67g0foyzc. Troubleshooting Log from Gnome Boxes is available here: https://pastebin.com/9eWGYsJV. It was working all properly on Friday before I turn off my laptop. Any clue what could be wrong and how I could solve this issue (I digged the Internet for 2 hours without success)? Thanks in advance for your help! Kind regards, Michel

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[libvirt-users] Cannot get interface MTU - qemu quest fails to start off OpenVswitch
by lejeczek 13 May '19

13 May '19

hi guys I have a qemu guest and openvswitch bridge and the guest fails to start: $ virsh start work8 error: Failed to start domain work8-vm-win2016 error: Cannot get interface MTU on 'ovsbr0': No such device LXC guest which uses the same source network starts just fine. I'm on Centos 7 with openvswitch-2.9.0-3.el7.x86_64 from centos-openstack-pike repo and libvirt-4.5.0-10.el7_6.7.x86_64. Would anybody care to suggest a possible reson(s) causing the failure? many thanks, L.

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[libvirt-users] Running libvirtd out of source directory connection reset error
by Peter P. 10 May '19

10 May '19

Hi all, I'm getting started with hacking around with libvirt and am trying to familiarize myself with launching and running an instance of libvirtd I built from source on Centos 7.6. Following the instructions from https://libvirt.org/compiling.html to launch my built versions of libvirtd and virsh, I get the following error with no other context when trying to start a domain using "virsh start mydomain": error: Cannot recv data: Connection reset by peer Despite this error, I am able to run commands list virsh list. Are there additional parameters needed to launch libvirtd or additional services I need to start up alongside it? Thanks, Peter

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Re: [libvirt-users] disable libvirt-nwfilter
by Michal Privoznik 07 May '19

07 May '19

[Please keep the list CC-ed as it may help somebody from future when searching for solution to the same problem] On 5/6/19 6:08 PM, nakata(a)geekpit.org wrote: > Am 2019-05-06 16:26, schrieb Michal Privoznik: >> On 5/6/19 3:44 PM, nakata(a)geekpit.org wrote: >>> Hi, >>> >>> i want to disable the nwfilter functionality of libvirt. >>> It's surely nice for some people, nevertheless i don't want libvirt >>> to alter any netfilter rules, neither i want the according >>> functionality even available. >> >> It's not only NWFilter that will inject firewall rules. Depending on >> configuration it might also be the default network. >> >>> I know about nwfilter-undefine, but what i'm looking for is an option >>> to globally disable this functionality at all. Some config flag or >>> similar. >>> How can i achieve that? >> >> Unless you have a domain <interface/> defined so that it uses a >> nwfilter then no firwall rules are added by nwfilter code. >> >> If you still want to remove nwfilter module then just uninstall it, >> e.g. via: >> >> dnf remove libvirt-daemon-driver-nwfilter libvirt-daemon-config-nwfilter >> >> Michal > > Hi, > > me again. > Another question libvirt is adding chains. Where do i disable these: > > chains are LIBVIRT-{FWO,FWX,FWI, INP, OUT} > > These are absolutely and explicit unwanted. > Adding new rich features for folks is a fine thing, but i need an opt out. > Please, how do i get rid of it? As I've said, there are two sources which cause libvirt to insert FW rules. By uninstalling nwfilter module you've eliminated one. But since you're still able to run the domain this step was useless because your domain doesn't have nwfilter configured for any of its <interface/>-s and thus nwfilter module did nothing but sit there. The other module that is inserting FW rules is network module. Currently, when libvirtd is starting it reads all the configs of defined networks. If a NATed network is found then it creates those LIBVIRT-* chains and when the network is started then all the rules will be placed into those chains to not contaminate config set by sysadmin. There is patch to postpone creating the chains unitl network actually is starting: https://www.redhat.com/archives/libvir-list/2019-April/msg01547.html So your options here are: a) undefine all NATed networks (typically there's 'default' network) b) uninstall network module (but this will render all domains using <interface type='network'/> unable to start). As an extension to a) you can have a network with <forward mode='open'/> which preserves all the advantages of having a libvirt network but does not install any FW rules. Of course, any comments to aforementioned patch are welcome too. Michal

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[libvirt-users] Autodetecting backing file properties when using vol-create-as
by Gionatan Danti 07 May '19

07 May '19

Hi all, experimenting with vol-create-as, I think it should autodetect some data - filesize and backing file format, specifically. However, the current implementation require us to specify both filesize and backing file format. Considering that qemu-img already autodetects these data, there are any reason for the lack of autodetect by libvirt? Should I open a bugzilla issue? Below you can find a practical example of what I mean. System is CentOS Linux release 7.6.1810 (Core) with libvirt-4.5.0-10.el7_6.4.x86_64 Please let me know if I am missing something. Thanks. # create base file [root@singularity images]# qemu-img create base.qcow2 8G -f qcow2 Formatting 'base.qcow2', fmt=qcow2 size=8589934592 cluster_size=65536 lazy_refcounts=off refcount_bits=16 [root@singularity images]# qemu-img info base.qcow2 image: base.qcow2 file format: qcow2 virtual size: 8.0G (8589934592 bytes) disk size: 17K cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false # create overlay1.qcow2 via qemu-img; note how backing file format is autodetected ("-f qcow2" regards the overlay file itself) [root@singularity images]# qemu-img create -b /var/lib/libvirt/images/base.qcow2 overlay1.qcow2 -f qcow2 Formatting 'overlay1.qcow2', fmt=qcow2 size=8589934592 backing_file=/var/lib/libvirt/images/base.qcow2 cluster_size=65536 lazy_refcounts=off refcount_bits=16 [root@singularity images]# qemu-img info overlay1.qcow2 image: overlay1.qcow2 file format: qcow2 virtual size: 8.0G (8589934592 bytes) disk size: 17K cluster_size: 65536 backing file: /var/lib/libvirt/images/base.qcow2 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false # try the same with virsh vol-create-as; note how you must specify filesize and the backing file format is *wrong* (leading to an unusable overlay disk) [root@singularity images]# virsh vol-create-as default overlay2.qcow2 8G --format qcow2 --backing-vol /var/lib/libvirt/images/base.qcow2 Vol overlay2.qcow2 created [root@singularity images]# qemu-img info overlay2.qcow2 image: overlay2.qcow2 file format: qcow2 virtual size: 8.0G (8589934592 bytes) disk size: 17K cluster_size: 65536 backing file: /var/lib/libvirt/images/base.qcow2 backing file format: raw Format specific information: compat: 0.10 refcount bits: 16 -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti(a)assyoma.it - info(a)assyoma.it GPG public key ID: FF5F32A8

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[libvirt-users] disable libvirt-nwfilter
by nakata＠geekpit.org 07 May '19

07 May '19

Hi, i want to disable the nwfilter functionality of libvirt. It's surely nice for some people, nevertheless i don't want libvirt to alter any netfilter rules, neither i want the according functionality even available. I know about nwfilter-undefine, but what i'm looking for is an option to globally disable this functionality at all. Some config flag or similar. How can i achieve that? greetings

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[libvirt-users] VM: Unable to enable scatter-gather / tx-checksumming / tcp-segmentation offload
by Harsh Gondaliya 06 May '19

06 May '19

In my Linux VM, I am unable to change scatter-gather / tx-checksumming / TCP-segmentation offload features by ethtool command. I am using virtio nic with vhostuser port backend. It shows me an error: Cannot change tx-checksumming Cannot change scatter-gather Cannot change tcp-segmentation offload Could not change any device features Ony running command ethtool -k ens3, I get the following: [image: image.png] If there is something that needs to be changed in the domain XML itself then please guide me what changes to do?

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