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

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=0... > > > > > > 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 Here is the bug report: https://bugs.launchpad.net/nova/+bug/1425115