July 2019 - Users - libvirt List Archives

[libvirt-users] bridge / ubuntu / no arp reply
by François Chenais 15 Oct '26

15 Oct '26

Hello I'm trying to setup a bridged guest on an ubuntu 13.10 but it doesn't work. (Everything is ok with NAT) Network sniffing shows that arp replies don't come back to the guest. Test 1 ------ Guest : ping host_bridge_ip (ok) Test 2 ------ Guest: ping other_lan_host (KO) other_lan_host - receives arp who-is request - sends arp reply - arp -a shows the guest macaddr => Guest doesn't receive reply Test 3 ------ other_lan_host ping the Guest (KO) - arp -a shows "incomplete" addr - Guest receives nothing On Host ------- network tcpdump on bridge or vnet interfaces shows request but no reply ... Thanks in advance for help or ideas François

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[libvirt-users] [virtual interface] detach interface during boot succeed with no changes
by Yalan Zhang 08 Sep '22

08 Sep '22

Hi guys, when I detach an interface from vm during boot (vm boot not finished), it always fail. I'm not sure if there is an existing bug. I have confirmed with someone that for disk, there is similar behavior, if this is also acceptable? # virsh destroy rhel7.2; virsh start rhel7.2 ;sleep 2; virsh detach-interface rhel7.2 network 52:54:00:98:c4:a0; sleep 2; virsh dumpxml rhel7.2 |grep /interface -B9 Domain rhel7.2 destroyed Domain rhel7.2 started Interface detached successfully <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/> </controller> <interface type='network'> <mac address='52:54:00:98:c4:a0'/> <source network='default' bridge='virbr0'/> <target dev='vnet0'/> <model type='rtl8139'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> When I detach after the vm boot, expand the sleep time to 10, it will succeed. # virsh destroy rhel7.2; virsh start rhel7.2 ;sleep 10; virsh detach-interface rhel7.2 network 52:54:00:98:c4:a0; sleep 2; virsh dumpxml rhel7.2 |grep /interface -B9 Domain rhel7.2 destroyed Domain rhel7.2 started Interface detached successfully ------- Best Regards, Yalan Zhang IRC: yalzhang Internal phone: 8389413

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[libvirt-users] Add Virtlyst to the list of libvirt users
by Daniel Nicoletti 23 Sep '20

23 Sep '20

Hi, I've just released v1.0.0 of Virtlyst[1] a web tool to manage VMs using Qt/C++/Cutelyst https://dantti.wordpress.com/2018/04/19/announcing-virtlyst-a-web-interface… Thanks. 1 - https://github.com/cutelyst/Virtlyst -- Daniel Nicoletti KDE Developer - http://dantti.wordpress.com

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[libvirt-users] Question about disabling UFO on guest
by Bao Nguyen 05 Aug '20

05 Aug '20

Hello everyone, I would like to ask a question regarding to disable UFO of virtio vNIC in my guest. I have read the document at https://libvirt.org/formatdomain.html *host* The csum, gso, tso4, tso6, ecn and ufo attributes with possible values on and off can be used to turn off host offloading options. By default, the supported offloads are enabled by QEMU. *Since 1.2.9 (QEMU only)* The mrg_rxbuf attribute can be used to control mergeable rx buffers on the host side. Possible values are on (default) and off. *Since 1.2.13 (QEMU only)* *guest* The csum, tso4, tso6, ecn and ufo attributes with possible values on and off can be used to turn off guest offloading options. By default, the supported offloads are enabl ed by QEMU. *Since 1.2.9 (QEMU only)* Then I disabled UFO on my vNIC on guest as the following configuration <devices> <interface type='network'> <source network='default'/> <target dev='vnet1'/> <model type='virtio'/> <driver name='vhost' txmode='iothread' ioeventfd='on' event_idx='off' queues='5' rx_queue_size='256' tx_queue_size='256'> *<host gso='off' ufo='off' />* *<guest ufo='off'/>* </driver> </interface> </devices> Then I reboot my node to get the change effect and it works. However, can I disable the UFO without touching the host OS? or it always has to disable on both host and guest like that? Thanks, Brs, Natsu

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[libvirt-users] OVS / KVM / libvirt / MTU
by Sven Vogel 09 Aug '19

09 Aug '19

Hey there, I hope anyone can bring some light in the following problem. <interface type='bridge'> <source bridge='cloudbr0'/> <mtu size='2000'/> <mac address='02:00:74:76:00:01'/> <model type='virtio'/> <virtualport type='openvswitch'> </virtualport> <vlan trunk='no'> <tag id='2097'/> </vlan><link state='up'/> </interface> we have an base bridge for example and cloudbr0. After we add an mtu to the vm bridge here it seems the base bridge gets the same mtu like the vnet adapter. Is this normal behaviour of libvirt together with OVS? —ovs-vsctl show 5b154321-534d-413e-9761-60476ae06640 Bridge "cloudbr0" Port "cloudbr0" Interface "cloudbr0" type: internal —MTU from the bridge after set an MTU into the XML File (before we had here 9000) mtu : 2000 mtu_request : [] name : "cloudbr0" ofport : 65534 —MTU of the vnet interface mac_in_use : "fe:00:74:76:00:01" mtu : 1450 mtu_request : 1450 name : „vnet2" Thanks for help… __ Sven Vogel Teamlead Platform EWERK RZ GmbH Brühl 24, D-04109 Leipzig P +49 341 42649 - 11 F +49 341 42649 - 18 S.Vogel(a)ewerk.com www.ewerk.com Geschäftsführer: Dr. Erik Wende, Hendrik Schubert, Frank Richter Registergericht: Leipzig HRB 17023 Zertifiziert nach: ISO/IEC 27001:2013 DIN EN ISO 9001:2015 DIN ISO/IEC 20000-1:2011 EWERK-Blog | LinkedIn | Xing | Twitter | Facebook Auskünfte und Angebote per Mail sind freibleibend und unverbindlich. Disclaimer Privacy: Der Inhalt dieser E-Mail (einschließlich etwaiger beigefügter Dateien) ist vertraulich und nur für den Empfänger bestimmt. Sollten Sie nicht der bestimmungsgemäße Empfänger sein, ist Ihnen jegliche Offenlegung, Vervielfältigung, Weitergabe oder Nutzung des Inhalts untersagt. Bitte informieren Sie in diesem Fall unverzüglich den Absender und löschen Sie die E-Mail (einschließlich etwaiger beigefügter Dateien) von Ihrem System. Vielen Dank. The contents of this e-mail (including any attachments) are confidential and may be legally privileged. If you are not the intended recipient of this e-mail, any disclosure, copying, distribution or use of its contents is strictly prohibited, and you should please notify the sender immediately and then delete it (including any attachments) from your system. Thank you.

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[libvirt-users] Researching why different cache modes result in 'some' guest filesystem corruption..
by vincent＠cojot.name 02 Aug '19

02 Aug '19

Hi All, I've been chasing down an issue in recent weeks (my own lab, so no prod here) and I'm reaching out in case someone might have some guidance to share. I'm running fairly large VMs (RHOSP underclouds - 8vcpu, 32gb ram, about 200gb single disk as a growable qcow2) on some RHEL7.6 hypervisors (kernel 3.10.0-927.2x.y, libvirt 4.5.0, qemu-kvm-1.5.3) on top of SSD/NVMe drives with various filesystems (vxfs, zfs, etc..) and using ECC RAM. The issue can be described as follows: - the guest VMs work fine for a while (days, weeks) but after a kernel update (z-stream) comes in, I am often greeted by the following message immediately after rebooting (or attempting to reboot into the new kernel): "error: not a correct xfs inode" - booting the previous kernel works fine and re-generating the initramfs for the new kernel (from the n-1 kernel) does not solve anything. - if booted from an ISO, xfs_repair does not find errors. - on ext4, there seems to be some kind of corruption there too. I'm building the initial guest image qcow2 for those guest VMs this way: 1) start with a rhel-guest image (currently rhel-server-7.6-update-5-x86_64-kvm.qcow2) 2) convert to LVM by doing this: qemu-img create -f qcow2 -o preallocation=metadata,cluster_size=1048576,lazy_refcounts=off final_guest.qcow2 512G virt-format -a final_guest.qcow2 --partition=mbr --lvm=/dev/rootdg/lv_root --filesystem=xfs guestfish --ro -a rhel_guest.qcow2 -m /dev/sda1 -- tar-out / - | \ guestfish --rw -a final_guest.qcow2 -m /dev/rootdg/lv_root -- tar-in - / 3) use "final_guest.qcow2" as the basis for my guests with LVM. After chasing down this issue some more and attempting various things (build the image on Fedora29, build a real XFS filesystem inside a VM and use the generated qcow2 as a basis instead of virt-format).. ..I've noticed that the SATA disk of each of those guests were using 'directsync' (instead of 'Hypervisor Default'). As soon as I switched to 'None', the XFS issues disappeared and I've now applied several consecutive kernel updates without issues. Also, 'directsync' or 'writethrough', while providing decent performance, both exhibited the XFS 'corruption' behaviour.. Only 'none' seem to have solved that. I've read the docs but I thought it was OK to use those modes (UPS, Battery-Backed RAID, etc..) Does anyone have any idea what's going on or what I may be doing wrong? Thanks for reading, Vincent

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[libvirt-users] Why librbd disallow VM live migration if the disk cache mode is not none or directsync
by Ming-Hung Tsai 01 Aug '19

01 Aug '19

I'm curious that why librbd sets this limitation? The rule first appeared in librbd.git commit d57485f73ab. Theoretically, a write-through cache is also safe for VM migration, if the cache implementation guarantees that cache invalidation and disk write are synchronous operations. For example, I'm using Ceph RBD images as VM storage backend. The Ceph librbd supports synchronous write-through cache, by setting rbd_cache_max_dirty to zero, and setting rbd_cache_block_writes_upfront to true, thus it would be safe for VM migration. Is that true? Any suggestion would be appreciated. Thanks. Ming-Hung Tsai

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[libvirt-users] Libvirt Virtualization Problem
by 王金磊 30 Jul '19

30 Jul '19

Dear Sir/Madam: I use virt-manager to create a new virtual machine(it's name is generic), then I edit generic to set it's cpu_mode as 'host-model', and I start it, but when dumpxml generic, it's cpu_mode is changed as 'custom'. I want to know that why it is? And what's the principle of dumpxml? Thanks! A user of libvirt

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[libvirt-users] virsh command to list CPU,Memory and Storage
by Kaushal Shriyan 30 Jul '19

30 Jul '19

Hi, Is there a way to find out total CPU's, Memory and Storage using virsh command? For example virsh list --all list out all VM's 11 dockerregistry01 running 12 gitlab running Any help will be highly appreciated. Thanks in Advance. Best Regards, Kaushal

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[libvirt-users] <VM LIVE Migration> <Sync conntrack entries>
by bharath paulraj 26 Jul '19

26 Jul '19

Hi Team, I am using QEMU/KVM for launching VMs and libvirt to govern those VMs. I would like to synchronise the connection tracking entries specific to the VM during the VM LIVE migrations. It is required when the firewall is implemented at the host level like libvirt's "network filters". If stateful firewall is enabled, then unless these connection tracking entries are synchronised, all the connections to the VM are lost and all TCP connections should be reestablished. Is there any option already available? I don't think current libvirt hooks are helpful, as VM pause in the source hypervisor and VM on in the destination hypervisor is done by QEMU and it does not wait for any application that needs to sync-up some metadata — In my case, it is conntrack entries. Also I tried with the existing hooks - stop, release, startcpus and nothing worked well. Has anybody came across similar scenario? If yes, how you overcome this? -- Regards, Bharath

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