12:33 p.m.
On 03/06/16 14:05 +0300, Дмитрий Глушенок wrote:
Thank you Martin!
Actually I tried the workaround hook, provided in [2], but then VDSM (oVirt 3.6.6) tries
to interpret hostdev in XML as PCI device, which leads to:
::The vm start process failed
Traceback (most recent call last):
File "/usr/share/vdsm/virt/vm.py", line 703, in _startUnderlyingVm
self._run()
File "/usr/share/vdsm/virt/vm.py", line 1949, in _run
self._domDependentInit()
File "/usr/share/vdsm/virt/vm.py", line 1797, in _domDependentInit
self._getUnderlyingVmDevicesInfo()
File "/usr/share/vdsm/virt/vm.py", line 1738, in _getUnderlyingVmDevicesInfo
self._getUnderlyingHostDeviceInfo()
File "/usr/share/vdsm/virt/vm.py", line 4277, in _getUnderlyingHostDeviceInfo
**self._getUnderlyingDeviceAddress(source))
TypeError: pci_address_to_name() got an unexpected keyword argument 'target'
XML part was:
<hostdev managed="no" mode="subsystem" rawio="yes"
type="scsi">
<source>
<adapter name="scsi_host2"/>
<address bus="0" target="1" unit="0"/>
</source>
</hostdev>
<hostdev managed="no" mode="subsystem" rawio="yes"
type="scsi">
<source>
<adapter name="scsi_host2"/>
<address bus="0" target="2" unit="0"/>
</source>
</hostdev>
As of creating custom partition - by default machine.slice has "a *:* rwm" in
devices.list. But for every new VM libvirt removes *:* mask and fills the list with
actually needed devices (as I understand the process). For example:
c 136:* rw
c 1:3 rw
c 1:7 rw
c 1:5 rw
c 1:8 rw
c 1:9 rw
c 5:2 rw
c 10:232 rw
c 253:0 rw
c 10:228 rw
c 10:196 rw
What I'm looking for is a way to tell libvirt about my additional devices without
breaking oVirt.
The solution would be creating your own partition and somehow (e.g.
VDSM hook) appending
<resource>
<partition>/machine/custom</partition>
</resource>
to the libvirt's <domain> element. I'm not sure how feasible creating
your own partition is though. I've tried the process as follows:
$ cat ~/create-partition.sh
# sh ~/create-partition.sh
for i in blkio cpu,cpuacct cpuset devices freezer memory net_cls perf_event
do
mkdir /sys/fs/cgroup/$i/machine.slice/custom.partition
done
for i in cpuset.cpus cpuset.mems
do
cat /sys/fs/cgroup/cpuset/machine.slice/$i >
/sys/fs/cgroup/cpuset/machine.slice/custom.partition/$i
done
(creates /machine/custom partition).
Now, we can create vdsm before_vm_start hook that will set given partition
for the VM:
$ pwd /usr/libexec/vdsm/hooks/before_vm_start
$ cat 10_cgroups
#!/usr/bin/python
import hooking
def custom_partition(domxml):
resource = domxml.createElement('resource')
partition = domxml.createElement('partition')
partition_text = domxml.createTextNode('/machine/custom')
partition.appendChild(partition_text)
resource.appendChild(partition)
return resource
domxml = hooking.read_domxml()
domain = domxml.getElementsByTagName('domain')[0]
domain.appendChild(custom_partition(domxml))
hooking.write_domxml(domxml)
--
Dmitry Glushenok
Jet Infosystems
http://www.jet.msk.su
+7-495-411-7601 (ext. 1237)
> 3 июня 2016 г., в 12:24, Martin Polednik <mpolednik(a)redhat.com> написал(а):
>
> On 03/06/16 11:48 +0300, Дмитрий Глушенок wrote:
>> Hello!
>>
>> Is it possible to tell libvirt to add specific devices to qemu cgroup? By somehow
enumerating the devices in XML using a hook for example.
>> I'm passing scsi-generic disks (/dev/sgX) to VM using qemucmdline hook and it
doesn't work until I remove "devices" from cgroup_controllers in qemu.conf.
>
> One way to achieve this is creating a hook to generate the scsi device
> XML instead of modifying qemu cmdline directly. Libvirt assumes
> ownership of all devices created in the XML and therefore adds them to
> the machine cgroup.
>
> Example of the XML taken from [1]:
> <devices>
> <hostdev mode='subsystem' type='scsi' sgio='filtered'
rawio='yes'>
> <source>
> <adapter name='scsi_host0'/>
> <address bus='0' target='0' unit='0'/>
> </source>
> <readonly/>
> <address type='drive' controller='0' bus='0'
target='0' unit='0'/>
> </hostdev>
> </devices>
>
> There is slight issue with this approach outlined in [2].
>
> If you want to keep the qemu approach, I think creating a custom
> partition and moving devices there would be the cleanest approach. In
> this case, [3] could help but I'm not entirely sure if that would
> solve the issue.
>
> [1] https://libvirt.org/formatdomain.html
> [2] https://bugzilla.redhat.com/show_bug.cgi?id=1325485
> [3] https://libvirt.org/cgroups.html
>> --
>> Dmitry Glushenok
>> Jet Infosystems
>> http://www.jet.msk.su
>> +7-495-411-7601 (ext. 1237)
>>
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