October 2017 - 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] 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] net interface direct - no IP communication between guest & host
by lejeczek 01 Nov '17

01 Nov '17

hi everyone I wonder why, when I attach an interface like this: virsh # attach-interface --domain win10Ent --type direct --source nm-team --config --persistent --model virtio host cannot ip ping the guest and vice versa, yet guest can ping other nodes(outside of its host, connected via phys net via a switch) Would you know? I thought maybe routing on the host, so I did: $ route add -host 192.168.2.222 dev nm-team but to no avail. I wonder if it's lower layer, arp kernel bits? thanks, L.

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[libvirt-users] libvirt/dnsmasq is not adhering to static DHCP assignments
by Dagmawi Biru 31 Oct '17

31 Oct '17

Given the following network configuration: =========== <network> <name>osc_mgmt</name> <uuid>d93fe709-14ae-4a0e-8989-aeaa8c76c513</uuid> <forward mode='route'/> <bridge name='osc_mgmt' stp='on' delay='0'/> <mac address='52:54:00:3f:fe:10'/> <ip address='192.168.80.254' netmask='255.255.255.0'> <dhcp> <range start='192.168.80.1' end='192.168.80.200'/> <host mac='52:54:00:2c:85:92' name='openstack-controller-00' ip='192.168.80.1'/> <host mac='52:54:00:e2:4b:25' name='openstack-database-00' ip='192.168.80.2'/> <host mac='52:54:00:50:91:04' name='openstack-keystone-00' ip='192.168.80.3'/> <host mac='52:54:00:fe:5b:36' name='openstack-rabbitmq-00' ip='192.168.80.7'/> <host mac='52:54:00:95:ca:bd' name='openstack-glance-00' ip='192.168.80.5'/> </dhcp> </ip> </network> When attempting to bring up the relevant interface in the virtual machine, I get an incorrect IP address assigned, different from the one I statically set up per the XML above. As you can see, the device with MAC '52:54:00:e2:4b:25' should really be getting 192.168.80.2, but what happens when we bring this interface up is this: =========== root@openstack-database-00:/home/osc# ifup ens11 Internet Systems Consortium DHCP Client 4.3.3 Copyright 2004-2015 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/ens11/... Sending on LPF/ens11/... Sending on Socket/fallback DHCPDISCOVER on ens11 to 255.255.255.255 port 67 interval 3 (xid=0x6769e42a) DHCPREQUEST of 192.168.80.27 on ens11 to 255.255.255.255 port 67 (xid=0x2ae46967) DHCPOFFER of 192.168.80.27 from 192.168.80.254 DHCPACK of 192.168.80.27 from 192.168.80.254 bound to 192.168.80.27 -- renewal in 1407 seconds. Some additional info about the VM and network it's attached to =========== [root@dragon dnsmasq]# virsh domiflist openstack-database-00 Interface Type Source Model MAC ------------------------------------------------------- vnet12 bridge br20 virtio 52:54:00:6c:ce:b9 vnet13 network VM_MGMT rtl8139 52:54:00:7d:ca:87 vnet14 network osc_mgmt rtl8139 52:54:00:e2:4b:25 [root@dragon dnsmasq]# virsh net-info osc_mgmt Name: osc_mgmt UUID: d93fe709-14ae-4a0e-8989-aeaa8c76c513 Active: yes Persistent: yes Autostart: yes Bridge: osc_mgmt =========== What's strange is that the first VM seems to work correctly and gets an assigned address of 192.168.80.1, but for some reason the others don't. Any ideas?

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[libvirt-users] guest state "in shutdown"
by Lying 30 Oct '17

30 Oct '17

Hello,I just encountered a problem my virtual machine is not a normal shutdown and I get state is "in shutdown" when i check it using "virsh list --all" why i get the error state,and how i should solve it?

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[libvirt-users] guest cost long time to boot
by 柘龙义 26 Oct '17

26 Oct '17

hello, my virtual guest always cost long times to boot, all device load finish ,but still cost 15s to make display light

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Re: [libvirt-users] Need to increase the rx and tx buffer size of my interface
by Ashish Kurian 26 Oct '17

26 Oct '17

Hi Yalan, In the previous email you mentioned "tx_queue_size='512' will not work in the guest with direct type interface, in fact, no matter what you set, it will not work and guest will get the default '256'. " So if I am using macvtap for my interfaces, then the device type will always be direct type. Does it mean that there is no way I can increase the buffer size with the macvtap interfaces? Best Regards, Ashish Kurian On Thu, Oct 26, 2017 at 9:04 AM, Ashish Kurian <ashishbnv(a)gmail.com> wrote: > Hi Yalan, > > Thank you for your comment on qemu-kvm-rhev > > I am waiting for a response about my previous email with the logs > attached. I do not understand what is the problem. > > > On Oct 26, 2017 8:58 AM, "Yalan Zhang" <yalzhang(a)redhat.com> wrote: > > Hi Ashish, > > Please never mind for qemu-kvm-rhev. > qemu with the code base 2.10.0 will support the tx_queue_size and > rx_queue_size. > > Thank you~ > > > > > > ------- > Best Regards, > Yalan Zhang > IRC: yalzhang > Internal phone: 8389413 > > On Thu, Oct 26, 2017 at 2:22 PM, Yalan Zhang <yalzhang(a)redhat.com> wrote: > >> Hi Ashish, >> >> Are these packages available for free? How can I install them? >> => You did have vhost backend driver. Do not set <driver name='qemu'...>, >> by default it will use vhost as backend driver. >> >> Is it possible to have my interfaces with an IP address inside the VM to >> be bridged to the physical interfaces on the host? >> => Yes, you can create a linux bridge with physical interface connected, >> and use bridge type interface. Refer to https://libvirt.org/formatd >> omain.html#elementsNICSBridge >> direct type is also ok (but your host and guest have no access to each >> other). >> >> Is it also a possibility that I change the rx and tx buffer on the >> physical interface on the host and it is reflected automatically inside the >> VM as you said it will always receive the default value of the host? >> => No, it do not receive the default value of the host. It's the default >> value related with the virtual device driver on the guest. >> hostdev type interface will passthrough the physical interface or VF of >> the host to guest, it will get the device's parameters for rx and tx buffer. >> >> >> >> ------- >> Best Regards, >> Yalan Zhang >> IRC: yalzhang >> Internal phone: 8389413 >> >> On Thu, Oct 26, 2017 at 1:30 PM, Ashish Kurian <ashishbnv(a)gmail.com> >> wrote: >> >>> Hi Yalan, >>> >>> Thank you for your response. I do not have the following packages >>> installed >>> >>> vhost backend driver >>> qemu-kvm-rhev package >>> >>> Are these packages available for free? How can I install them? >>> >>> In my KVM VM, I must have an IP address to the interfaces that I am >>> trying to increasing the buffers. That is the reason I was using macvtap >>> (direct type interface). Is it possible to have my interfaces with an IP >>> address inside the VM to be bridged to the physical interfaces on the host? >>> >>> Is it also a possibility that I change the rx and tx buffer on the >>> physical interface on the host and it is reflected automatically inside the >>> VM as you said it will always receive the default value of the host? >>> >>> >>> Best Regards, >>> Ashish Kurian >>> >>> On Thu, Oct 26, 2017 at 6:45 AM, Yalan Zhang <yalzhang(a)redhat.com> >>> wrote: >>> >>>> Hi Ashish, >>>> >>>> I have tested with your xml in the first mail, and it works for rx_queue_size(see >>>> below). >>>> multiqueue need to work with vhost backend driver. And when you set >>>> "queues=1" it will ignored. >>>> >>>> Please check your qemu-kvm-rhev package, should be newer than >>>> qemu-kvm-rhev-2.9.0-16.el7_4.2 >>>> And the logs? >>>> >>>> tx_queue_size='512' will not work in the guest with direct type >>>> interface, in fact, no matter what you set, it will not work and guest will >>>> get the default '256'. >>>> We only support vhost-user backend to have more than 256. refer to >>>> https://libvirt.org/formatdomain.html#elementsNICSEthernet >>>> >>>> tx_queue_size >>>> The optional tx_queue_size attribute controls the size of virtio ring >>>> for each queue as described above. The default value is hypervisor >>>> dependent and may change across its releases. Moreover, some hypervisors >>>> may pose some restrictions on actual value. For instance, QEMU v2.9 >>>> requires value to be a power of two from [256, 1024] range. In addition to >>>> that, this may work only for a subset of interface types, e.g. >>>> aforementioned QEMU enables this option only for vhostuser type. Since >>>> 3.7.0 (QEMU and KVM only) >>>> multiqueue only supports vhost as backend driver. >>>> >>>> # rpm -q libvirt qemu-kvm-rhev >>>> libvirt-3.2.0-14.el7_4.3.x86_64 >>>> qemu-kvm-rhev-2.9.0-16.el7_4.9.x86_64 >>>> >>>> 1. the xml as below >>>> <interface type='direct'> >>>> <mac address='52:54:00:00:b5:99'/> >>>> <source dev='eno1' mode='vepa'/> >>>> <model type='virtio'/> >>>> <driver name='vhost' queues='5' rx_queue_size='512' >>>> tx_queue_size='512'> >>>> <host csum='off' gso='off' tso4='off' tso6='off' ecn='off' >>>> ufo='off' mrg_rxbuf='off'/> >>>> <guest csum='off' tso4='off' tso6='off' ecn='off' ufo='off'/> >>>> </driver> >>>> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' >>>> function='0x0'/> >>>> </interface> >>>> >>>> 2. after start the vm, check the qemu command line: >>>> *-netdev >>>> tap,fds=26:28:29:30:31,id=hostnet0,vhost=on,vhostfds=32:33:34:35:36* >>>> -device virtio-net-pci,csum=off,gso=off,host_tso4=off,host_tso6=off, >>>> host_ecn=off,host_ufo=off,mrg_rxbuf=off,guest_csum=off,guest >>>> _tso4=off,guest_tso6=off,guest_ecn=off,guest_ufo=off, >>>> *mq=on,vectors=12,rx_queue_size=512,tx_queue_size=512*,netdev=hostnet >>>> 0,id=net0,mac=52:54:00:00:b5:99,bus=pci.0,addr=0x3 >>>> >>>> 3. check on guest >>>> # ethtool -g eth0 >>>> Ring parameters for eth0: >>>> Pre-set maximums: >>>> RX: *512 ==> rx_queue_size works* >>>> RX Mini: 0 >>>> RX Jumbo: 0 >>>> TX: *256 ===> no change* >>>> Current hardware settings: >>>> RX: *512 **==> rx_queue_size works* >>>> RX Mini: 0 >>>> RX Jumbo: 0 >>>> TX: *256 ===> no change* >>>> >>>> # ethtool -l eth0 >>>> Channel parameters for eth0: >>>> Pre-set maximums: >>>> RX: 0 >>>> TX: 0 >>>> Other: 0 >>>> Combined: *5 ==> queues what we set* >>>> Current hardware settings: >>>> RX: 0 >>>> TX: 0 >>>> Other: 0 >>>> Combined: 1 >>>> >>>> >>>> If change to qemu as driver, >>>> # virsh edit rhel7 >>>> .. >>>> <interface type='direct'> >>>> <mac address='52:54:00:00:b5:99'/> >>>> <source dev='eno1' mode='vepa'/> >>>> <model type='virtio'/> >>>> <driver name='qemu' queues='5' rx_queue_size='512' >>>> tx_queue_size='512'> >>>> <host csum='off' gso='off' tso4='off' tso6='off' ecn='off' >>>> ufo='off' mrg_rxbuf='off'/> >>>> <guest csum='off' tso4='off' tso6='off' ecn='off' ufo='off'/> >>>> </driver> >>>> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' >>>> function='0x0'/> >>>> </interface> >>>> .. >>>> Domain rhel7 XML configuration edited. ==> the xml can validate and save >>>> >>>> # virsh start rhel7 >>>> Domain rhel7 started >>>> >>>> >>>> # virsh dumpxml rhel7 | grep /interface -B9 >>>> <source dev='eno1' mode='vepa'/> >>>> <target dev='macvtap0'/> >>>> <model type='virtio'/> >>>> *<driver name='qemu' queues='5' rx_queue_size='512' >>>> tx_queue_size='512'>* >>>> <host csum='off' gso='off' tso4='off' tso6='off' ecn='off' >>>> ufo='off' mrg_rxbuf='off'/> >>>> <guest csum='off' tso4='off' tso6='off' ecn='off' ufo='off'/> >>>> </driver> >>>> <alias name='net0'/> >>>> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' >>>> function='0x0'/> >>>> </interface> >>>> >>>> >>>> * -netdev tap,fds=26:28:29:30:31*,id=hostnet0 -device >>>> virtio-net-pci,csum=off,gso=off,host_tso4=off,host_tso6=off, >>>> host_ecn=off,host_ufo=off,mrg_rxbuf=off,guest_csum=off,guest >>>> _tso4=off,guest_tso6=off,guest_ecn=off,guest_ufo=off, >>>> *rx_queue_size=512,tx_queue_size=512*,netdev=hostnet0,id=net0,mac=52: >>>> 54:00:00:b5:99,bus=pci.0,addr=0x3 >>>> >>>> *"mq=on,vectors=12" is missing*, indicates there is no multiqueue >>>> >>>> and check on guest >>>> >>>> # ethtool -l eth0 >>>> Channel parameters for eth0: >>>> Pre-set maximums: >>>> RX: 0 >>>> TX: 0 >>>> Other: 0 >>>> Combined: 1 ==> no multiqueue >>>> Current hardware settings: >>>> RX: 0 >>>> TX: 0 >>>> Other: 0 >>>> Combined: 1 >>>> >>>> # ethtool -g eth0 >>>> Ring parameters for eth0: >>>> Pre-set maximums: >>>> RX: *512* >>>> RX Mini: 0 >>>> RX Jumbo: 0 >>>> TX: 256 >>>> Current hardware settings: >>>> RX: *512* >>>> RX Mini: 0 >>>> RX Jumbo: 0 >>>> TX: 256 >>>> >>>> >>>> >>>> >>>> ------- >>>> Best Regards, >>>> Yalan Zhang >>>> IRC: yalzhang >>>> Internal phone: 8389413 >>>> >>>> On Thu, Oct 26, 2017 at 2:33 AM, Ashish Kurian <ashishbnv(a)gmail.com> >>>> wrote: >>>> >>>>> Hi Michal, >>>>> >>>>> An update to what I have already said : when I try adding <driver >>>>> name='qemu' txmode='iothread' ioeventfd='on' event_idx='off' queues='1' >>>>> rx_queue_size='512' tx_queue_size='512'> although it showed me the error as >>>>> mentioned, when I checked the xml again I saw that <driver >>>>> name='qemu' txmode='iothread' ioeventfd='on' event_idx='off' > is added to >>>>> the interface. >>>>> >>>>> The missing parameters are : queues='1' rx_queue_size='512' >>>>> tx_queue_size='512' >>>>> >>>>> Best Regards, >>>>> Ashish Kurian >>>>> >>>>> On Wed, Oct 25, 2017 at 5:07 PM, Ashish Kurian <ashishbnv(a)gmail.com> >>>>> wrote: >>>>> >>>>>> Hi Michal, >>>>>> >>>>>> What I found was that when I restarted the machine and did a virsh >>>>>> edit command to see the xml config, I see that it is was not actually >>>>>> changed. This suggests why I saw 256 again after restarting. >>>>>> >>>>>> So now I tried again to edit the xml via virsh edit command and used >>>>>> the following to set the parameters. >>>>>> >>>>>> <driver name='qemu' txmode='iothread' ioeventfd='on' event_idx='off' >>>>>> queues='1' rx_queue_size='512' tx_queue_size='512'> >>>>>> </driver> >>>>>> >>>>>> It was not accepted and I got the error saying : >>>>>> >>>>>> >>>>>> error: XML document failed to validate against schema: Unable to >>>>>> validate doc against /usr/share/libvirt/schemas/domain.rng >>>>>> Extra element devices in interleave >>>>>> Element domain failed to validate content >>>>>> >>>>>> What does this imply? I have two more other interfaces and do I have >>>>>> to the same to them also? >>>>>> >>>>>> Btw, there are now logs generated now in the domain log or libvirtd >>>>>> log >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> Best Regards, >>>>>> Ashish Kurian >>>>>> >>>>>> On Wed, Oct 25, 2017 at 2:50 PM, Michal Privoznik < >>>>>> mprivozn(a)redhat.com> wrote: >>>>>> >>>>>>> On 10/25/2017 01:53 PM, Ashish Kurian wrote: >>>>>>> > Dear Users/Developers, >>>>>>> > >>>>>>> > I am using a KVM Ubuntu VM as a degrader to apply specific delays >>>>>>> to >>>>>>> > incoming packets. As the delay for my packets can be higher than >>>>>>> 7.5 >>>>>>> > seconds, there is not enough buffer on my interface to buffer all >>>>>>> the >>>>>>> > packets. Therefore those overflowing packets are dropped in the >>>>>>> machine and >>>>>>> > not forwarded. >>>>>>> > >>>>>>> > When I tried to use the command ethtool -G ens8 rx 512 to >>>>>>> increase the >>>>>>> > buffer size, I get the following error. >>>>>>> > >>>>>>> > Cannot set device ring parameters: Operation not permitted >>>>>>> > >>>>>>> > I have kept the VM xml files as specified in the link : >>>>>>> > https://libvirt.org/formatdomain.html. The value that I kept in >>>>>>> my xml file >>>>>>> > is as follows. >>>>>>> > >>>>>>> > <interface type='direct'> >>>>>>> > <mac address='52:54:00:72:f9:eb'/> >>>>>>> > <source dev='enp7s0f0' mode='vepa'/> >>>>>>> > <model type='virtio'/> >>>>>>> > <driver name='vhost' queues='5' rx_queue_size='512' >>>>>>> > tx_queue_size='512'> >>>>>>> > <host csum='off' gso='off' tso4='off' tso6='off' ecn='off' >>>>>>> ufo='off' >>>>>>> > mrg_rxbuf='off'/> >>>>>>> > <guest csum='off' tso4='off' tso6='off' ecn='off' ufo='off'/> >>>>>>> > </driver> >>>>>>> > <address type='pci' domain='0x0000' bus='0x00' slot='0x08' >>>>>>> > function='0x0'/> >>>>>>> > </interface> >>>>>>> > <interface type='direct'> >>>>>>> > <mac address='52:54:00:00:b5:99'/> >>>>>>> > <source dev='enp7s0f1' mode='vepa'/> >>>>>>> > <model type='virtio'/> >>>>>>> > <driver name='vhost' queues='5' rx_queue_size='512' >>>>>>> > tx_queue_size='512'> >>>>>>> > <host csum='off' gso='off' tso4='off' tso6='off' ecn='off' >>>>>>> ufo='off' >>>>>>> > mrg_rxbuf='off'/> >>>>>>> > <guest csum='off' tso4='off' tso6='off' ecn='off' ufo='off'/> >>>>>>> > </driver> >>>>>>> > <address type='pci' domain='0x0000' bus='0x00' slot='0x09' >>>>>>> > function='0x0'/> >>>>>>> >>>>>>> So what does the qemu command line look like? You can find it in >>>>>>> either >>>>>>> libvirtd log or domain log. >>>>>>> >>>>>>> http://wiki.libvirt.org/page/DebugLogs >>>>>>> >>>>>>> Michal >>>>>>> >>>>>> >>>>>> >>>>> >>>>> _______________________________________________ >>>>> libvirt-users mailing list >>>>> libvirt-users(a)redhat.com >>>>> https://www.redhat.com/mailman/listinfo/libvirt-users >>>>> >>>> >>>> >>> >> > >

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[libvirt-users] question about how to set rng device on vm
by Yalan Zhang 26 Oct '17

26 Oct '17

Hi Amos, I'm a libvirt QE, and I can not understand the setting on libvirt.org for rng device. Could you please help to explain a little? (The xml in https://libvirt.org/formatdomain.html#elementsRng) <devices> <rng model='virtio'> <rate period="2000" bytes="1234"/> <backend model='random'>/dev/random</backend>  <backend model='egd' type='udp'> *<source mode='bind' service='1234'/>* * <source mode='connect' host='1.2.3.4' service='1234'/>* </backend> </rng> </devices> How did it work with source mode='bind' and source mode='connect' together? which process on guest or host will act as server part, which for client part? One detail example: start a vm with below device, and no egd running on host: <rng model='virtio'> <backend model='egd' type='udp'> <source mode='bind' service='1234'/> <source mode='connect' host='127.0.0.1' service='1234'/> </backend> <address type='pci' domain='0x0000' bus='0x00' slot='0x09' function='0x0'/> </rng> qemu command line: -chardev udp,id=charrng0,host=127.0.0.1,port=1234,localaddr=,localport=1234 -object rng-egd,id=objrng0,chardev=charrng0 -device virtio-rng-pci,rng=objrng0,id=rng0,bus=pci.0,addr=0x9 In my understanding the purpose of the rng device on guest is to provide guest a hardware RNG device /dev/hwrng which obtain seeds from the host. The source can be /dev/random on host, then the xml will be: <rng model='virtio'> <backend model='random'>/dev/random</backend> </rng> can be hardware on host: <rng model='virtio'> <backend model='random'>/dev/hwrng</backend> </rng> can be edg daemon running on host: <rng model='virtio'> <backend model='egd' type='tcp'> <source mode='connect' host='127.0.0.1' service='1234'/> </backend> </rng> (on host, there should be a egd daemon running on tcp 127.0.0.1:1234 # egd.pl --debug-client --nofork localhost:1234) Thank you very much and look forward for your response! ------- Best Regards, Yalan Zhang IRC: yalzhang Internal phone: 8389413

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