Re: [libvirt] libvirt/libxl implemetation of get_online_cpu / virNodeGetCPUMap?

[Manish Jaggi <mjaggi@caviumnetworks.com>]

On Tuesday 24 February 2015 08:30 PM, Anthony PERARD wrote:
> On Tue, Feb 24, 2015 at 01:22:19PM +0000, Daniel P. Berrange wrote:
>> On Tue, Feb 24, 2015 at 01:15:57PM +0000, Anthony PERARD wrote:
>>> On Tue, Feb 24, 2015 at 12:46:44PM +0000, Daniel P. Berrange wrote:
>>>> On Tue, Feb 24, 2015 at 12:41:01PM +0000, Anthony PERARD wrote:
>>>>> Hi,
>>>>>
>>>>> A recent OpenStack nova commit make use of virNodeGetCPUMap to get the list
>>>>> of online cpu of a host. But this API is not implemented for the libvirt
>>>>> xen driver.
>>>>>
>>>>> The commit:
>>>>>    Add handling for offlined CPUs to the nova libvirt driver.
>>>>> https://review.openstack.org/gitweb?p=openstack/nova.git;a=commitdiff;h=0696a5cd5f0fdc08951a074961bb8ce0c3310086
>>>> FWIW, this should not impact Xen based on my understanding. The code
>>>> path in question should only be used when Nova is setup todo NUMA
>>>> pinning support, and that is not supported with Xen in OpenStack,
>>>> only KVM.  Did it actually cause failures for you, or are you simply
>>>> keeping track of all used APIs in Nova as a sanity check ?
>>> It prevent nova from starting. I do the setup with DevStack.
>>>
>>> The error:
>>> libvirtError: this function is not supported by the connection driver: virNodeGetCPUMap
>>>
>>> And a part of the traceback:
>>>    File "/opt/stack/nova/nova/openstack/common/service.py", line 491, in run_service
>>>      service.start()
>>>    File "/opt/stack/nova/nova/service.py", line 181, in start
>>>      self.manager.pre_start_hook()
>>>    File "/opt/stack/nova/nova/compute/manager.py", line 1188, in pre_start_hook
>>>      self.update_available_resource(nova.context.get_admin_context())
>>>    File "/opt/stack/nova/nova/compute/manager.py", line 6062, in update_available_resource
>>>      rt.update_available_resource(context)
>>>    File "/opt/stack/nova/nova/compute/resource_tracker.py", line 315, in update_available_resource
>>>      resources = self.driver.get_available_resource(self.nodename)
>>>    File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 4896, in get_available_resource
>>>      numa_topology = self._get_host_numa_topology()
>>>    File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 4749, in _get_host_numa_topology
>>>      online_cpus = self._host.get_online_cpus()
>>>    File "/opt/stack/nova/nova/virt/libvirt/host.py", line 599, in get_online_cpus
>>>      (cpus, cpu_map, online) = self.get_connection().getCPUMap()
>>>
>>> I'll look into why nova is going through NUMA code paths then.
>> Oh damn, yes, I understand why now. Please file a bug against Nova for
>> this, as we must fix it as a high pripority. It was certainly not my
>> intention to break Xen when I approved this change
I applied the patch, not getting this python libvirtError, but libvirt 
deamon is throwing error.
2015-03-24 08:46:31.169+0000: 1030: error : virNodeGetCPUMap:1342 : this 
function is not supported by the connection driver: virNodeGetCPUMap

> Here is the bug report: https://bugs.launchpad.net/nova/+bug/1425115
>
> Regards,
>