[libvirt-users] virRandomBits - not very random
by Brian Rak
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.
6 years, 6 months
[libvirt-users] Freeze Windows Guests For Consistent Storage Snapshots
by Payes Anand
Hi,
Is it possible to freeze windows guests for a consistent storage level
snapshot.
I am using openstack icehouse on centos 6.6
Hypervisor: KVM
Libvirt: 0.10.2
Qemu: 0.10.2
Guest OS: Windows 7 and Windows Server 2008
I was able to freeze Centos guests by issuing the command:
virsh qemu-agent-command <guest_ID> '{"execute":"guest-fsfreeze-freeze"}'
For CentOS guests, I enabled access between compute nodes and guests
through a socket by setting metadata parameter, hw_qemu_guest_agent=yes for
the guest image.
And then installing qemu-guest-agent inside the guest.
What steps do i have to follow for windows ?
Regars,
Payes
9 years, 6 months
[libvirt-users] QEMU interface type=ethernet
by Brian Rak
With Libvirt under modern kernels, you can't use <interface
type='ethernet'> unless QEMU is running as root.
Running qemu as root is not ideal, but I was able to track down the
issue to this linux change:
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id...
Which means that if you're seeing errors like this:
2015-03-02T18:00:51.243477Z qemu-kvm: -netdev
tap,script=/tmp/vnet380622.sh,id=hostnet1: could not open /dev/net/tun:
Operation not permitted
2015-03-02T18:00:51.243518Z qemu-kvm: -netdev
tap,script=/tmp/vnet380622.sh,id=hostnet1: Device 'tap' could not be
initialized
They can be resolved like this:
1) Edit /etc/libvirt/qemu.conf, and add "/dev/net/tun" to the
cgroup_device_acl option
2) Run: setcap cap_net_admin+eip /bin/qemu-system-x86_64
This will give QEMU CAP_NET_ADMIN when it runs. Make sure you review
`man capabilities` to see what capabilities this actually gets qemu.
The downside here is that in the event a guest somehow breaks out of
qemu, CAP_NET_ADMIN gives them a bunch of scary permissions that could
result in you having a seriously bad day (it's enough permissions to
MITM all the machine's traffic, which could easily result in compromise)
It looks to me like libvirt already has the ability to create tap
devices and pass them into qemu (src/util/virnetdevtap.c -
virNetDevTapCreateInBridgePort), however you need to actually be using a
bridged network to do this. There is no way to have libvirt just create
a tap device and leave the rest to user defined scripts.
I don't think I have the necessary knowledge to add that feature in a
generic way, but it seems like it would be pretty handy. I'll probably
just work around it by removing the virNetDevBridgeAddPort call from our
version of libvirt.
9 years, 8 months
[libvirt-users] How to burn a CD using libvirt?
by Steve Ross
Hi,
My first e-mail... my apologies if this is not the appropriate e-mail list.
My goal is to *write* from the guest OS to a CD or DVD reader/writer on
my host system. Currently, the write operation is failing. I believe
it is because the virtual CD-ROM device is set to be "readonly". Is it
possible to write to a QEMU CDROM device and, if so, how? (The host
machine's CD-ROM drive does support writing/burning.)
I'm using the "virt-manager" GUI to start the virtual machine. Once
started, the "qemu" command line from my virtual machine process
includes the following, where the host's built-in CD reader/writer is
"/dev/sr0".
/usr/bin/qemu-system-x86_64 ... -drive
file=/dev/sr0,if=none,id=drive-ide0-0-1,readonly=on,format=raw
This obviously says that the device is "readonly".
A snippet of XML from my virtual machine from the CDROM is:
<domain type='kvm'>
...
<devices>
<disk type='block' device='cdrom'>
<driver name='qemu' type='raw'/>
<source dev='/dev/sr0'/>
<target dev='hdb' bus='ide'/>
<readonly/>
<address type='drive' controller='0' bus='0' target='0' unit='1'/>
</disk>
I've tried removing the <readonly/> tag from the above VM definition,
and then running the VM, but the tag magically reappears in the VM
definition when it runs.
Also, the "virt-manager" GUI shows the CDROM device as having the option
of "Readonly" being checked (and the GUI does not allow me to uncheck it.)
Other details:
* qemu version 2.1.3 on Fedora 21.
* libvirt version 1.2.0.2
Thanks for any help or pointers you can provide,
-- Steve
9 years, 8 months
[libvirt-users] XML vm configfile with Display using QEMU GTK interface
by Vinícius Ferrão
Hello guys,
I'm trying to start a VM using the QEMU GTK Display Interface instead of a SDL window. But I'm failing.
My actual setting is using SDL with this XML line:
<graphics type='sdl' display=':0.0' xauth='/home/ploog/.Xauthority'/>
I changed to:
<graphics type='gtk'>
But it fails to start the VM.
Any ideias?
Thanks in advance,
9 years, 8 months
[libvirt-users] couple of ceph/rbd questions
by Brian Kroth
Hi, I've recently been working on setting up a set of libvirt compute
nodes that will be using a ceph rbd pool for storing vm disk image
files. I've got a couple of issues I've run into.
First, per the standard ceph documentation examples [1], the way to add a
disk is to create a block in the VM definition XML that looks something
like this:
<disk type='network' device='disk'>
<source protocol='rbd' name='libvirt-pool/new-libvirt-image'>
<host name='{monitor-host-1}' port='6789'/>
<host name='{monitor-host-2}' port='6789'/>
<host name='{monitor-host-3}' port='6789'/>
</source>
<target dev='vda' bus='virtio'/>
<auth username='libvirt'>
<secret type='ceph' uuid='9ec59067-fdbc-a6c0-03ff-df165c0587b8'/>
</auth>
</disk>
The trouble with this approach is that those ceph cluster details
(secret uuid and monitor host lists), need to be stored separately in
every single VM disk definition separately. That makes for a lot of
maintenance when those details need to change (eg: replace a monitor
host (common), or change the auth details (less common)).
I'd prefer to be able to define a libvirt storage pool that contains
those details, and then reference the disks within each VM as volumes,
so that I only need to change the ceph monitor/auth details once per
libvirt compute host, rather than for every single VM disk definition.
I've rebuilt my libvirt packages using --with-rbd-support so that I can
successfully define a libvirt storage pool as follows:
<pool type='rbd'>
<name>libvirt-rbd-pool</name>
<source>
<name>libvirt-pool</name>
<host name='{monitor-host-1}' port='6789'/>
<host name='{monitor-host-2}' port='6789'/>
<host name='{monitor-host-3}' port='6789'/>
<auth username='libvirt' type='ceph'>
<secret uuid='9ec59067-fdbc-a6c0-03ff-df165c0587b8'/>
</auth>
</source>
</pool>
However, when I go to start a VM with a volume created in that pool as
follows, I get an error:
<disk type='volume' device='disk'>
<source pool='libvirt-rbd-pool' volume='{rbd-volume-name}'/>
<driver name='qemu' type='raw' cache='writethrough'/>
<target dev='vda' bus='virtio'/>
</disk>
"using 'rbd' pools for backing 'volume' disks isn't yet supported"
When I dug through the code, it appears that there's an explicit check
for RBD type storage pools (VIR_STORAGE_POOL_RBD) that disables that
(libvirt-1.2.13/src/storage/storage_driver.c:3159).
Is there a particular reason for that? Has it just not been implemented
yet, or am I specifying the disk definition in the wrong way?
Second, using the former disk definition method, I'm able to run VMs
under qemu, *and* migrate them. Very slick. Nice work all.
However, I found that since by default virt-manager leaves the VM
defined on both the source and destination, I'm actually able to start
the VM in both places. I didn't see an option to disable that, so I
just wrote a simple wrapper script to do the right thing via virsh using
--undefinesource, but I can't guarantee that some other admin might not
skip that and just use the GUI. It appears that libvirt (or is it
qemu?) doesn't set rbd locks on the disk image files by default.
After running across [2], I had originally thought about writing some
hooks to set and release locks on the VMs using the rbd cli, but after
reading the docs on the migration process [3], I think that's probably
not possible since the VM is started in both places temporarily.
I think my other option is to setup some shared fs (maybe cephfs) and
point virtlockd at it so that all of the libvirt compute hosts register
locks on VMs properly. However, I thought I'd ask if anyone knows if
there's some magic other parameter or setting I can use to have
libvirt/qemu just use rbd locks natively. Or, is that not implemented
either?
Thanks for your help.
Cheers,
Brian
[1] <http://ceph.com/docs/master/rbd/libvirt/#configuring-the-vm>
[2] <https://www.redhat.com/archives/libvirt-users/2014-January/msg00058.html>
[3] <https://libvirt.org/hooks.html#qemu_migration>
9 years, 8 months
[libvirt-users] Networking issues in host
by G. Richard Bellamy
I've been having intermittent network issues on my Host - they go away when
I stop and disable libvirtd and then reboot. They do not go away if I just
stop libvirtd and don't reboot.
I'm at a loss as to where to start with my troubleshooting, and being a
relative n00b to libvirt, I'd love any pointers.
Regards,
Richard
9 years, 8 months
[libvirt-users] No package 'libvirt' found
by Rudy YAYON
Hi,
After successful libvirt compilation on Cygwin, I am trying to run virt-manage which requests LibvirtGLib:
$ virt-manager
Traceback (most recent call last):
File "/usr/share/virt-manager/virt-manager", line 30, in <module>
from gi.repository import LibvirtGLib
ImportError: cannot import name LibvirtGLib
I understand that I need to compile libvirt-glib. The problem is that I get the following error once running ./configure:
checking whether C compiler handles -fexceptions... yes
checking whether C compiler handles -fasynchronous-unwind-tables... yes
checking whether C compiler handles -fipa-pure-const... yes
checking whether C compiler handles -Wno-suggest-attribute=pure... yes
checking whether C compiler handles -Wno-suggest-attribute=const... yes
checking for pkg-config... /usr/bin/pkg-config
checking pkg-config is at least version 0.9.0... yes
checking for LIBVIRT... no
configure: error: Package requirements (libvirt >= 0.10.2) were not met:
No package 'libvirt' found
Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.
Alternatively, you may set the environment variables LIBVIRT_CFLAGS
and LIBVIRT_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.
The only "libraries" I have been able to find are:
$ cp /usr/local/bin/cygvirt-
cygvirt-0.dll cygvirt-lxc-0.dll cygvirt-qemu-0.dll
Copying it to /usr/lib doesn't change anything. Renaming these files from cygvirt* to libvirt* either.
Any idea?
Cordialement,Rudy YAYON
9 years, 9 months
Re: [libvirt-users] 答复: libvirtd can't start
by Martin Kletzander
On Thu, Mar 26, 2015 at 02:55:04PM +0800, 梅磊 wrote:
>Thanks for your reply, Martin, I have read the coredump, but I am not familiar with libvirt, so could you help me to figure it out why it crash?
>Attachment is the coredump gdb output and all the generate files when libvirtd stop.
>
I forgot to ask you to install debuginfo packages to further
investigate. But looking at the log only netcf-debuginfo is needed.
Could you install it and then run the "t a a bt f" again, please?
From the current logs I can only guess that there is some network XML
mangled and netcf can't read it. When you're power went out, as you
said, is it possible you were updating something in the meantime? Try
running "rpm -Va" to see if there's something broken in the system.
>And Do you think this issue is the same issue with the below root cause?
>https://bugzilla.redhat.com/show_bug.cgi?id=1179981
>
It is not, that is caused by something else.
>
>
>
>-Best Regards,
>Andy
>
>
>-----邮件原件-----
>发件人: Martin Kletzander [mailto:mkletzan@redhat.com]
>发送时间: 24 March 2015 21:20
>收件人: 梅磊
>抄送: libvirt-users(a)redhat.com
>主题: Re: [libvirt-users] libvirtd can't start
>
>On Tue, Mar 24, 2015 at 04:29:07PM +0800, 梅磊 wrote:
>>Hi experts,
>> The libvirtd can’t start on my server after the server interruption of
>>power supply, the status is below:
>>
>>[root@openstack3 libvirt]# service libvirtd status Redirecting to
>>/bin/systemctl status libvirtd.service libvirtd.service -
>>Virtualization daemon
>> Loaded: loaded (/usr/lib/systemd/system/libvirtd.service; enabled)
>> Active: failed (Result: signal) since Tue 2015-03-24 16:10:31 CST;
>>7min ago
>> Process: 27372 ExecStart=/usr/sbin/libvirtd $LIBVIRTD_ARGS
>>(code=killed,
>>signal=SEGV)
>> Main PID: 27372 (code=killed, signal=SEGV)
>>
>>Mar 24 16:10:31 openstack3 libvirtd[27372]: 2015-03-24 08:10:31.412+0000:
>>27383: debug : virFileClose:90 : Closed fd 22 Mar 24 16:10:31
>>openstack3 libvirtd[27372]: 2015-03-24 08:10:31.412+0000:
>>27383: debug : virFileClose:90 : Closed fd 22 Mar 24 16:10:31
>>openstack3 libvirtd[27372]: 2015-03-24 08:10:31.412+0000:
>>27383: debug : virFileClose:90 : Closed fd 22 Mar 24 16:10:31
>>openstack3 libvirtd[27372]: 2015-03-24 08:10:31.412+0000:
>>27383: debug : virFileClose:90 : Closed fd 22 Mar 24 16:10:31
>>openstack3 libvirtd[27372]: 2015-03-24 08:10:31.413+0000:
>>27383: debug : virFileClose:90 : Closed fd 22 Mar 24 16:10:31
>>openstack3 libvirtd[27372]: 2015-03-24 08:10:31.413+0000:
>>27383: debug : virStateInitialize:847 : Running global init for netcf
>>state driver Mar 24 16:10:31 openstack3 libvirtd[27372]: 2015-03-24
>>08:10:31.413+0000:
>>27383: debug : virObjectNew:199 : OBJECT_NEW: obj=0x7f73f0080d00
>>classname=virNetcfDriverState Mar 24 16:10:31 openstack3
>>libvirtd[27372]: ====== end of log ===== Mar 24 16:10:31 openstack3
>>systemd[1]: libvirtd.service: main process exited, code=killed,
>>status=11/SEGV Mar 24 16:10:31 openstack3 systemd[1]: Unit
>>libvirtd.service entered failed state.
>>
>>And the attachment is the log after restart the libvirtd.
>>
>>After long time search on google, I didn’t get any useful information,
>>so anyone can give me some hint on this issue?
>>
>
>What did you search for?
>
>According to the log:
>abrt-hook-ccpp: Saved core dump of pid 28928 (/usr/sbin/libvirtd) to
>/var/tmp/abrt/ccpp-2015-03-24-16:19:22-28928 (97218560 bytes)
>
>libvirtd has segfaulted and you have the coredump. Use gdb to open
>it:
># gdb -c /var/tmp/abrt/ccpp-2015-03-24-16:19:22-28928
>
>and then look at what happened, if you can't make anything of it, post it as an attachment here or create a bug from it:
>
>(gdb) bt
>(gdb) t a a bt full
>
>>-BR,
>>Andy
>>
>
>
>>_______________________________________________
>>libvirt-users mailing list
>>libvirt-users(a)redhat.com
>>https://www.redhat.com/mailman/listinfo/libvirt-users
9 years, 9 months
[libvirt-users] Channel Device virConnectListAllNodeDevices
by Neel Basu
Hello,
I've added a Channel Device through virt-manager GUI. virsh dumpxml shows
the device as.
<channel type='unix'>
<source mode='bind'
path='/var/lib/libvirt/qemu/channel/target/ubuntusaucy.marx'/>
<target type='virtio' name='marx'/>
<alias name='channel2'/>
<address type='virtio-serial' controller='0' bus='0' port='3'/>
</channel>
I am expecting virConnectListAllNodeDevices to have the device in its
output. But I don't see it there. Is it the right function to call ?
virNodeDevicePtr* devices;
int dev_count = virConnectListAllNodeDevices(conn, &devices, 0);
std::cout << "Devices: " << dev_count << std::endl;
for(virNodeDevicePtr* device = devices; device < devices+dev_count;
++device){
std::cout << virNodeDeviceGetName(*device) << std::endl;
}
returns 66 devices but once I loop through devices I don't get any
corresponding name for the channel device.
Tried using
virConnectListAllNodeDevices(conn, &devices,
VIR_CONNECT_LIST_NODE_DEVICES_CAP_VPORTS);
returns 0 devices.
Thanks.
9 years, 9 months
