February 2016 - 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] ceph rbd pool and libvirt manageability (virt-install)
by Jelle de Jong 28 Aug '18

28 Aug '18

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello everybody, I created a rbd pool and activated it, but I can't seem to create volumes in it with virsh or virt-install? # virsh pool-dumpxml myrbdpool <pool type='rbd'> <name>myrbdpool</name> <uuid>2d786f7a-2df3-4d79-ae60-1535bcf1c6b5</uuid> <capacity unit='bytes'>6997998301184</capacity> <allocation unit='bytes'>10309227031</allocation> <available unit='bytes'>6977204658176</available> <source> <host name='ceph01.powercraft.nl' port='6789'/> <host name='ceph02.powercraft.nl' port='6789'/> <host name='ceph03.powercraft.nl' port='6789'/> <name>libvirt-pool</name> <auth type='ceph' username='libvirt'> <secret uuid='029a334e-ed57-4293-bb99-ffafa8867122'/> </auth> </source> </pool> # virt-install --version 1.0.1 # virsh --version 1.2.9 I ended using virsh edit ceph-test.powercraft.nl and making creating the disk manually. <disk type='network' device='disk'> <auth username='libvirt'> <secret type='ceph' uuid='029a334e-ed57-4293-bb99-ffafa8867122'/> </auth> <source protocol='rbd' name='libvirt-pool/kvm01-storage'> <host name='ceph01.powercraft.nl' port='6789'/> <host name='ceph02.powercraft.nl' port='6789'/> <host name='ceph03.powercraft.nl' port='6789'/> </source> <target dev='vdc' bus='virtio'/> </disk> I use virt-install a lot to define, import and undefine domains, how can I use virt-install to manage my rdb disks? Kind regards, Jelle de Jong -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iJwEAQECAAYFAlV1xlQACgkQ1WclBW9j5HkbPQP+PjNrzvlqysslOp2Yk7wH4Mxy 2sh2dn96G0KOAHEeEn3BN6IWlnD1TADZbHdpTtMwkdv48Xwn0sP1s+3QDM4pb3gP n+z+dVxS8FouDIy/eiso3IBCj3g4TWbEX8ZHqs3jKqe0lZgAXBzB9xYSUowcEBrZ ddkPbr8p8ozWyOG+9V8= =lkK7 -----END PGP SIGNATURE-----

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[libvirt-users] virRandomBits - not very random
by Brian Rak 01 Jun '18

01 Jun '18

I just ran into an issue where I had about 30 guests get duplicate mac addresses assigned. These were scattered across 30 different machines. Some debugging revealed that: 1) All the host machines were restarted within a couple seconds of each other 2) All the host machines had fairly similar libvirtd pids (within ~100 PIDs of each other) 3) Libvirt seeds the RNG using 'time(NULL) ^ getpid()' This perfectly explains why I saw so many duplicate mac addresses. Why is the RNG seed such a predictable value? Surely there has to be a better source of a random seed then the timestamp and the pid? The PID seems to me to be a very bad source of any randomness. I just ran a test across 60 of our hosts. 43 of them shared their PID with at least one other machine.

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[libvirt-users] unhelpful error message on failed "virsh migrate"
by Andreas Buschmann 01 Jun '16

01 Jun '16

Hello, I have two servers where I can push VMs from one to the other by issuing the command virsh migrate --live --persistent --copy-storage-all --verbose \ test6 qemu+ssh://kvmhost2/system on kvmhost1. I can get the VM back by issuing the equivalent command on kvmhost2: virsh migrate --live --persistent --copy-storage-all --verbose \ test6 qemu+ssh://kvmhost1/system After an update (on behalf of the glibc bug) it only works for some VMs and fails for others. The error message is unhelpful: virsh --debug 4 migrate --live --persistent --copy-storage-all --verbose \ vmware-mgmt qemu+ssh://kvmhost1/system error: internal error: info migration reply was missing return status Is there a way to get a more helpful error message? migrating VMs only works for a very limited subset of the VMs on the system in the direction kvmhost2 --> kvmhost2 Stopping the VMs, copying them over to kvmhost1 and restarting still works, and I can even migrate them back. How do I debug this problem? One possible way would be to stop all VMs on kvmhost2, manually copy them to kvmhost1 and start them and afterwards reinstall all packages (or the whole Server if that doesn't help) But that would be a workaround, and I still would not know what the problem is. The system is CentOS 7.2 now and was CentOS 7.1 before the upgrade, with the qemu-kvm-rhev repo added for qemu. Mit freundlichen Gruessen Andreas Buschmann -- Andreas Buschmann [Senior Systems Engineer] net.DE AG

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[libvirt-users] Libvirt bite sized tasks
by Michal Privoznik 20 Mar '16

20 Mar '16

Dear lists, I've just started new wiki page which aim is to summarize small and trivial tasks, that starting contributors can take, investigate and implement. The aim is to give them something easy to start with while not scaring them out about complexity of our code. The page can be found here: http://wiki.libvirt.org/page/BiteSizedTasks The name is copied from qemu wiki: http://wiki.qemu.org/BiteSizedTasks Please, feel free to extend the list. I plan to use it in the future when interviewing GSoC candidates. Michal

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[libvirt-users] Zombie processes being created when console buffer is full
by Peter Steele 10 Mar '16

10 Mar '16

We have been researching stuck zombie processes in our libvirt lxc containers. What we found was: 1) Each zombie’s parent was pid 1. init which symlinks to systemd. 2) In some cases, the zombies were launched by systemd, in others the zombie was inherited. 3) While the child is in the zombie state, the parent process (systemd) /proc/1/status shows no pending signals. 4) Attaching gdb to systemd, there was 1 thread and it was waiting in write() and the file being written was /dev/console. This write() to the console never returns. We operated under the assumption that systemd's SIGCHLD handler sets a bit and a foreground thread (the only thread) would see that child processes needed reaping. While the single thread is stuck in write(), the reaping never takes place. So why is write() blocking? The answer seems to be that there is nothing draining the console and eventually it blocks write() when its buffers become full. When we attached to the container's console, the buffer is cleared allowing systemd’s write() to return. The zombies are then reaped and everything goes back to normal. Our “solution” was more of a workaround. systemd was altered to log errors/warnings/etc to /dev/null instead of /dev/console. This prevented the problem, only in that the console buffer was unlikely to get filled up since systemd generally is the only then that writes to it. This is definitely a hack though. This may be a bug in the libvirt container library (you can't expect something to periodically connect to a container's console to empty it out). We suspect there may also be a configuration issue in our containers with regards to the console. Has anyone else observed this problem? Peter _______________________________________________ libvirt-users mailing list libvirt-users(a)redhat.com https://www.redhat.com/mailman/listinfo/libvirt-users

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[libvirt-users] Network speed between two guests on same host.
by Dominique Ramaekers 29 Feb '16

29 Feb '16

Hi, I've got two hosts. Most of my guests are Windows systems. I'm using LANBench to test network performance. 1) From an physical PC to a guest (it doesn't matter on which host), I get almost 1Gb/s. They are connected through a 1Gb/s swich => very good! 2) From a guest on one host to a guest on the other host => plusminus 1Gb/s => Okay! 3) Between two guests on the same host => plusminus 230Mb/s ??? The guests have network over a bridged interface, so I tried the same test over a NAT interface => The same 230Mb/s... Is there a way to tweak connection speeds between two guest running on the same host? Thanks in advance... An piece of the xml dump of one of the guests: <domain type='kvm' id='17'> <name>PCVIRTdra</name> <uuid>925e4f9b-2c27-406d-bdd9-f3e0b44f28bb</uuid> <title>PCVIRTdra - PC voor dra</title> <description></description> <memory unit='KiB'>2097152</memory> <currentMemory unit='KiB'>2097152</currentMemory> <memoryBacking> <hugepages/> </memoryBacking> <vcpu placement='static'>8</vcpu> <resource> <partition>/machine</partition> </resource> <os> <type arch='x86_64' machine='pc-i440fx-utopic'>hvm</type> <bootmenu enable='yes'/> </os> <features> <acpi/> <apic/> <hyperv> <relaxed state='on'/> <vapic state='on'/> <spinlocks state='on' retries='8191'/> </hyperv> </features> <cpu mode='custom' match='exact'> <model fallback='allow'>cpu64-rhel6</model> <topology sockets='2' cores='2' threads='2'/> </cpu> <clock offset='localtime'> <timer name='rtc' tickpolicy='catchup'/> <timer name='pit' tickpolicy='delay'/> <timer name='hpet' present='no'/> <timer name='hypervclock' present='yes'/> </clock> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <pm> <suspend-to-mem enabled='no'/> <suspend-to-disk enabled='no'/> </pm> <devices> .... <interface type='bridge'> <mac address='52:54:00:b1:41:b3'/> <source bridge='br0'/> <target dev='vnet4'/> <model type='virtio'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> .....

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[libvirt-users] ANNOUNCE: Oz 0.15.0 release
by Chris Lalancette 29 Feb '16

29 Feb '16

All, I'm pleased to announce release 0.15.0 of Oz. Oz is a program for doing automated installation of guest operating systems with limited input from the user. Release 0.15.0 is a bugfix and feature release for Oz. Some of the highlights between Oz 0.14.0 and 0.15.0 are: * Make sure openssh-clients is included in CentOS builds * Add support for Fedora-23 * Add customization support for Debian * Use the ssh -i option to avoid "Too many authentication failures" with many ssh keys * Support "rawhide" as a Fedora version * Add in Ubuntu 15.10 support * Add in OpenSUSE 13.2 support * Improve Oz's free port selection A tarball and zipfile of this release is available on the Github releases page: https://github.com/clalancette/oz/releases . Packages for Fedora-22, Fedora-23, and EPEL-7 have been built in Koji and will eventually make their way to stable. Instructions on how to get and use Oz are available at http://github.com/clalancette/oz/wiki . If you have questions or comments about Oz, please feel free to contact me at clalancette at gmail.com, or open up an issue on the github page: http://github.com/clalancette/oz/issues . Thanks to everyone who contributed to this release through bug reports, patches, and suggestions for improvement. Chris Lalancette

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[libvirt-users] Libvirt-lxc packages deprecation
by syed muhammad 24 Feb '16

24 Feb '16

Folks, I found this thread <https://www.redhat.com/archives/libvirt-users/2015-August/msg00026.html>that talks about deprecating libvirt-lxc packages [1] [2] [3] in RHEL7.1. I am using [1] as a dependency for my application deployed on RHEL7.2 servers. For now it works fine but I am not sure about the future RHEL releases. The plan of deprecation was delayed or cancelled? Can someone please share the latest state of this announcement? [1] libvirt-daemon-driver-lxc [2] libvirt-daemon-lxc [3] libvirt-login-shell Regards, Qasim Sarfraz

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[libvirt-users] High i/o-wait in guest but no i/o-wait on host
by Dennis Jacobfeuerborn 24 Feb '16

24 Feb '16

Hi, I have an issue with one of our CentOS 7 hypervisors. The system is a Dell server equipped with Samsung 840 Pro SSDs. What happens is that the guest does about 40MB/s of writes (mostly MySQL inserts) and ends up becoming almost unusable because of high i/o-wait numbers yet when I check on the host vmstat consistently shows i/o-wait being 0 the whole time. This is weird for two reasons: a) I would not expect 40MB/s to create such an extreme congestion on the SSDs. b) If that congestion is in fact real I would expect to see non-zero i/o-wait numbers on the host created by the corresponding qemu process. Right now it looks like the i/o requests get stuck in the guest even though there is no congestion on the host. Could this be a virtio bug? Has anyone an explanation for this strange behavior? Regards, Dennis

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