October 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] stream finish throws exception via python API
by Shahar Havivi 27 Nov '16

27 Nov '16

Hi, The following snippet works fine e.g. receiving the data but when calling stream.finish() we get the following error: stream = con.newStream() vol.download(stream, 0, 0, 0) buf = stream.recv(1024) stream.finish() libvirt: I/O Stream Utils error : internal error: I/O helper exited abnormally Traceback (most recent call last): File "./helpers/kvm2ovirt", line 149, in <module> download_volume(vol, item[1], diskno, disksitems, pksize) File "./helpers/kvm2ovirt", line 102, in download_volume stream.finish() File "/usr/lib64/python2.7/site-packages/libvirt.py", line 5501, in finish if ret == -1: raise libvirtError ('virStreamFinish() failed') libvirt.libvirtError: internal error: I/O helper exited abnormally Am I doing something wrong? Thank you, Shahar.

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[libvirt-users] sttic vnet device for guest
by Anton Gorlov 08 Nov '16

08 Nov '16

Can i assign static vnet* device for some guests?

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[libvirt-users] Guest startup process blocks if a hook's child process is still running (i.e : after forking)
by Nicolas Roy-Renaud 08 Nov '16

08 Nov '16

I've been having issues with KVM lately where I sometimes put my host into sleep while a guest is still running, which prevents it from waking up properly. This is somewhat expected due to my setup, but I have mistakenly done this more than once and could use a workaround to stop this from happening. So I've been trying to setup a libvirt hook to fork an instance of systemd-inhibit when the start hook is called and keep it running until the shutdown hook is called. This seems to work well when I run the hook script in a normal bash shell, but running it through libvirt simply blocks the starting process until systemd-inhibit quits. Here's the script : LOCK_FILE="/tmp/vfio-lock-$OBJECT" if [ "$OPERATION" == "start" ]; then ( touch "$LOCK_FILE"; systemd-inhibit --what="sleep" \ --who="libvirt" \ --mode="block" \ inotifywait -qq -e delete "$LOCK_FILE" ) & disown $! exit fi if [ "$OPERATION" == "shutdown" ]; then rm "$LOCK_FILE" fi Is there some way to make it so libvirt sees the hook script exiting and carries on with the rest of its guest startup process even after a process fork or would that require changes in the internal hook handling functions? - Nicolas

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[libvirt-users] pci-assign fails with read error on config-space file
by Henning Schild 02 Nov '16

02 Nov '16

Hey, i am running an unusual setup where i assign pci devices behind the back of libvirt. I have two options to do that: 1. a wrapper script for qemu that takes care of suid-root and appends arguments for pci-assign 2. virsh qemu-monitor-command ... 'device_add pci-assign...' I know i should probably not be doing this, it is a workaround to introduce fine-grained pci-assignment in an openstack setup, where vendor and device id are not enough to pick the right device for a vm. In both cases qemu will crash with the following output: > qemu: hardware error: pci read failed, ret = 0 errno = 22 followed by the usual machine state dump. With strace i found it to be a failing read on the config space file of my device. /sys/bus/pci/devices/0000:xx:xx.x/config A few reads out of that file succeeded, as well as accesses on vendor etc. Manually launching a qemu with the pci-assign works without a problem, so i "blame" libvirt and the cgroup environment the qemu ends up in. So i put a bash into the exact same cgroup setup - next to a running qemu, expecting a dd or hexdump on the config-space file to fail. But from that bash i can read the file without a problem. Has anyone seen that problem before? Right now i do not know what i am missing, maybe qemu is hitting some limits configured for the cgroups or whatever. I can not use pci-assign from libvirt, but if i did would it configure cgroups in a different way or relax some limits? What would be a good next step to debug that? Right now i am looking at kernel event traces, but the machine is pretty big and so is the trace. That assignment used to work and i do not know how it broke, i have tried combinations of several kernels, versions of libvirt and qemu. (kernel 3.18 and 4.4, libvirt 1.3.2 and 2.0.0, and qemu 2.2.1 and 2.7) All combinations show the same problem, even the ones that work on other machines. So when it comes to software versions the problem could well be caused by a software update of another component, that i got with the package manager and did not compile myself. It is a debian 8.6 with all recent updates installed. My guess would be that systemd could have an influence on cgroups or limits causing such a problem. regards, Henning

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[libvirt-users] pass-through hwrng
by lejeczek 01 Nov '16

01 Nov '16

hi all I have in my centos 7 this: crw-------. 1 root root 10, 183 Oct 11 21:28 /dev/hwrng and VM fails, complains like this: virsh # start volatile-work6 error: Failed to start domain volatile-work6 error: internal error: process exited while connecting to monitor: 2016-10-19T09:42:05.988142Z qemu-kvm: -object rng-random,id=objrng0,filename=/dev/hwrng: Could not open '/dev/hwrng': Permission denied which reads logical. Now - is this normal that hwrng is created with these permissions? And if yes then how to pass-through it to the VMs? How to aid VMs with hardware random numbers generator? many thanks. L

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[libvirt-users] How do you set real time bandwidth for a container?
by Peter Steele 30 Oct '16

30 Oct '16

When I create a VM using libvirt, the VM comes up the path /sys/fs/cgroup/cpu/cpu.rt_runtime_us set to something like 1000000. When I create a container however, the path /sys/fs/cgroup/cpu/cpu.rt_runtime_us is 0. This prevents my containers from being able to run any real time applications. I have to explicitly echo a value into this field in order to give the container some real time bandwidth and allow it to run real time processes. Is it possible to define this in a container's XML config? Or is there another method I should be using to enable real time capability in a container? Peter

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[libvirt-users] command guest-file-open failed to open file - Permission denied
by 刘梦可 30 Oct '16

30 Oct '16

hello, I am using libvirt 1.2.17 on CentOS 7.2 - kernel 3.10.0-327.13.1.el7.x86_64. The command guest-file-open failed to open file with error "Permission denied", the detail is as below: virsh qemu-agent-command instance-00000a9c '{"execute":"guest-file-open", "arguments":{"path":"/home/centos/test","mode":"r"}}' error: internal error: unable to execute QEMU agent command 'guest-file-open': failed to open file '/home/centos/test' (mode: 'r'): Permission denied In the guest, the file '/home/centos/test' exist and the access permissions is 777 as below: -rwxrwxrwx. 1 centos centos 18 Oct 27 11:16 test How can I fix it? Thanks very much!!! -mkliu28

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