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

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

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.

Thanks for your information,

-- 
Anthony PERARD

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel