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how to add LD_PRELOAD in the xml
by Marc 30 Dec '22

30 Dec '22

How should I add LD_PRELOAD to domain xml. I guess within: <qemu:commandline> <qemu:arg value='env=LD_PRELOAD=/usr/lib64/libtcmalloc.so'/> </qemu:commandline> but this is generating syntax errors.

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Fwd: Need help
by Gk Gk 22 Dec '22

22 Dec '22

FYI.... ---------- Forwarded message --------- From: Gk Gk <ygk.kmr(a)gmail.com> Date: Wed, Dec 21, 2022 at 9:46 PM Subject: Re: Need help To: Daniel P. Berrangé <berrange(a)redhat.com> I have just created a new vm and rechecked the disk stats. This time around too, they seem to be different as shown below: >From libvirt python library: --- disk_name=sda read_req=10501,read_bytes=263819776,write_req=1933,write_bytes=82269184 --- So the write_bytes from above amounted to 78 MB approx. But from within the vm : --- root@sample2:~# iostat -p sda -h Linux 4.15.0-101-generic (sample2) 12/21/2022 _x86_64_ (1 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 1.9% 0.0% 1.3% 0.4% 0.0% 96.4% Device tps kB_read/s kB_wrtn/s kB_read kB_wrtn sda 40.45 643.6k 21.2M 217.5M 7.2G sda1 40.04 637.6k 21.2M 215.5M 7.2G ---- 7.2 G is far from 78 MB. Am I doing wrong anywhere ? Btw, I did not reboot the new vm this time On Wed, Dec 21, 2022 at 9:30 PM Daniel P. Berrangé <berrange(a)redhat.com> wrote: > On Wed, Dec 21, 2022 at 09:26:14PM +0530, Gk Gk wrote: > > Thanks Daniel for the response. > > > > I am wondering what exactly is the difference in the process for a soft > and > > hard reboot in the context of a kvm guest ? Can you throw some light here > > please ? > > KVM will always do a soft reboot, where QEMU keeps running. > > > With regards, > Daniel > -- > |: https://berrange.com -o- > https://www.flickr.com/photos/dberrange :| > |: https://libvirt.org -o- > https://fstop138.berrange.com :| > |: https://entangle-photo.org -o- > https://www.instagram.com/dberrange :| > >

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Fwd: Need help
by Gk Gk 22 Dec '22

22 Dec '22

For larger reach....... ---------- Forwarded message --------- From: Gk Gk <ygk.kmr(a)gmail.com> Date: Thu, Dec 22, 2022 at 8:35 AM Subject: Re: Need help To: Daniel P. Berrangé <berrange(a)redhat.com> Hi Daniel, Did you get a chance to check this out ? Please let me know.... On Wednesday, December 21, 2022, Gk Gk <ygk.kmr(a)gmail.com> wrote: > I have just created a new vm and rechecked the disk stats. This time around too, they seem to be different as shown below: > From libvirt python library: > --- > disk_name=sda read_req=10501,read_bytes=263819776,write_req=1933,write_bytes=82269184 > --- > > So the write_bytes from above amounted to 78 MB approx. > But from within the vm : > --- > root@sample2:~# iostat -p sda -h > Linux 4.15.0-101-generic (sample2) 12/21/2022 _x86_64_ (1 CPU) > > avg-cpu: %user %nice %system %iowait %steal %idle > 1.9% 0.0% 1.3% 0.4% 0.0% 96.4% > > Device tps kB_read/s kB_wrtn/s kB_read kB_wrtn > sda > 40.45 643.6k 21.2M 217.5M 7.2G > sda1 > 40.04 637.6k 21.2M 215.5M 7.2G > ---- > 7.2 G is far from 78 MB. Am I doing wrong anywhere ? Btw, I did not reboot the new vm this time > > > > On Wed, Dec 21, 2022 at 9:30 PM Daniel P. Berrangé <berrange(a)redhat.com> wrote: >> >> On Wed, Dec 21, 2022 at 09:26:14PM +0530, Gk Gk wrote: >> > Thanks Daniel for the response. >> > >> > I am wondering what exactly is the difference in the process for a soft and >> > hard reboot in the context of a kvm guest ? Can you throw some light here >> > please ? >> >> KVM will always do a soft reboot, where QEMU keeps running. >> >> >> With regards, >> Daniel >> -- >> |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| >> |: https://libvirt.org -o- https://fstop138.berrange.com :| >> |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| >> >

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Need help
by Gk Gk 21 Dec '22

21 Dec '22

Hi All, I am trying to get guest VM's disk statistics using a libvirt python library as follows: --- raw_xml = domain.XMLDesc(0) for disk in doc.getElementsByTagName('disk'): disk_data = disk.getElementsByTagName('target') --- The above code is yielding the following stats for two disks inside the VM: -- disk_name=sda read_req=34137,read_bytes=445358592,write_req=2405970,write_bytes=24943391744 disk_name=sdb read_req=34357,read_bytes=450754048,write_req=2405984,write_bytes=24943465472 --- The write_bytes divided by 1024 yields 24358853 kB. But when I compare the above statistics from the iostat data shown from inside the VM, I see a stark difference between the two results as shown below: --- root@sample:~# iostat Linux 4.15.0-101-generic (sample) 12/21/2022 _x86_64_ (1 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 0.27 0.00 0.03 0.02 0.01 99.68 Device tps kB_read/s kB_wrtn/s kB_read kB_wrtn sda 0.24 0.04 11.87 400052 121844120 sdb 0.00 0.00 1.19 5269 12223752 ---- Why is there a huge difference in the number of bytes read and written for the two disks as reported by libvirt ? Please explain. Thanks Kumar

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[Question] Which qcow2 options could be inherited to snapshot/blockcopy?
by Meina Li 20 Dec '22

20 Dec '22

Hi, I'm trying to find out which qcow2 options could be inherited to snapshot/blockcopy and then test them. >From https://github.com/qemu/qemu/blob/master/qapi/block-core.json#L4720 we can know all the qcow2 options. As far as I know, size, cluster_size and extended-l2 have already been implemented. So I'm curious that: 1) What are the current status and future plans of other options? Like compat option. 2) Also whether the vol-clone can cover all options? Thank you very much. And please help to correct me if I have something wrong. Best Regards, Meina Li

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Failed to connect socket to '/var/run/libvirt/virtnetworkd-sock': No such file or directory
by 陈新隆 20 Dec '22

20 Dec '22

Hi team, i'm trying to hotplug an interface to guest, after execute the command below I got an error : ``` virsh attach-interface --domain 1 --type network --source net1 --model virtio-non-transitional --target /sys/devices/virtual/net/net1/tap603053 --mac ac:de:48:77:a2:32 --config --live error: Failed to attach interface error: Failed to connect socket to '/var/run/libvirt/virtnetworkd-sock': No such file or directory ``` According to https://libvirt.org/daemons.html there's two arch of daemon which is "monolithic" and "modular" , so I was wondering if I connect to the monolithic daemon (libvirtd) to attach the interface should works. Then I execute the command below : ``` bash-4.4# virsh -c qemu:///system?socket=/var/run/libvirt/libvirt-sock attach-interface --domain 1 --type network --source net1 --model virtio-non-transitional --target /sys/devices/virtual/net/net1/tap603053 --mac ac:de:48:77:a2:32 --config --live Authorization not available. Check if polkit service is running or see debug message for more information. error: Failed to attach interface error: Failed to connect socket to '/var/run/libvirt/virtnetworkd-sock': No such file or directory ``` Still, I got the same error. My question is : 1. How should I hotplug/unplug an interface without virtnetworkd ? 2. Am I right about the guess of "If I use monolithic daemon then I can hotplug/unplug an interface without virtnetworkd ?

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Testing DKIM handling
by dberrange＠yahoo.com 16 Dec '22

16 Dec '22

Testing DKIM handling RH mail servers

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Global option to configure tb-cache size for tcg feature
by Yatin Karel 16 Dec '22

16 Dec '22

Hi Team, In OpenStack Upstream CI as part of testing we have to create multiple guest vms together on a 8GB VM(no nested-virt support) so we have to use qemu emulation. But with Qemu>=5 'tb-cache' size has increased from 32MiB to 1GiB and due to this we cannot run multiple guest vms together as we have limited resources in CI. We tried to use some swap together but that too didn't helped much as it get's too slow. Thanks Libvirt-8.0.0 now allows to configure tcg feature as below in instance domain.xml:- <features> <tcg> <tb-cache unit='KiB'>32768</tb-cache> </tcg> </features> Is there some global option available in libvirt/qemu which we can use instead of changing each and every xml so we can avoid code changes in nova code[1] for just the CI use case? [1] https://bugs.launchpad.net/nova/+bug/1949606 PS: Please keep me in CC for responses as I am not subscribed to the mailing list. Thanks and Regards Yatin Karel

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qemu flags on libvirt attach-device
by Miguel Ping 13 Dec '22

13 Dec '22

Hello, Is it possible to supply additional flags to libvirt attach-device, similar to libvirt qemu passthrough ( https://libvirt.org/kbase/qemu-passthrough-security.html#xml-document-addit… The passthrough appears to work only for domain creation. I'm particularly interested in the "reconnect-delay" param for nbd based disks. Thanks

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Attach NBD device with qemu flags
by Miguel Ping 12 Dec '22

12 Dec '22

Is there a way to attach an nbd device via eg: virsh attach-device, and provide custom qemu flags? I'm particularly interested in the flag "reconnect-delay". I'm fine with using a language binding (eg: C, Java) for this. Thanks

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