nova-compute startup failure on Fedora 19 fresh install (no suitable emulator)

[Dan Prince]

Using the latest Nova havana release on Fedora 19. I see the following stack trace in Nova's compute.log file after performing a fresh install of Nova/libvirt/qemu and trying to start nova-compute:

2013-08-22 19:01:57.245 9050 ERROR nova.openstack.common.threadgroup [-] internal error Cannot find suitable emulator for x86_64
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup Traceback (most recent call last):
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/nova/openstack/common/threadgroup.py", line 117, in wait
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup x.wait()
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/nova/openstack/common/threadgroup.py", line 49, in wait
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup return self.thread.wait()
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/eventlet/greenthread.py", line 168, in wait
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup return self._exit_event.wait()
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/eventlet/event.py", line 116, in wait
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup return hubs.get_hub().switch()
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/eventlet/hubs/hub.py", line 187, in switch
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup return self.greenlet.switch()
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/eventlet/greenthread.py", line 194, in main
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup result = function(*args, **kwargs)
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/nova/openstack/common/service.py", line 65, in run_service
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup service.start()
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/nova/service.py", line 154, in start
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup self.manager.init_host()
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 756, in init_host
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup self._report_driver_status(context)
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/nova/compute/manager.py", line 4318, in _report_driver_status
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup capabilities = self.driver.get_host_stats(refresh=True)
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 3733, in get_host_stats
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup return self.host_state.get_host_stats(refresh=refresh)
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 374, in host_state
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup self._host_state = HostState(self)
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 4094, in __init__
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup self.update_status()
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 4134, in update_status
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup data["hypervisor_version"] = self.driver.get_hypervisor_version()
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/nova/virt/libvirt/driver.py", line 2939, in get_hypervisor_version
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup return method()
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/eventlet/tpool.py", line 187, in doit
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup result = proxy_call(self._autowrap, f, *args, **kwargs)
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/eventlet/tpool.py", line 147, in proxy_call
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup rv = execute(f,*args,**kwargs)
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib/python2.7/site-packages/eventlet/tpool.py", line 76, in tworker
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup rv = meth(*args,**kwargs)
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup File "/usr/lib64/python2.7/site-packages/libvirt.py", line 3550, in getVersion
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup if ret == -1: raise libvirtError ('virConnectGetVersion() failed', conn=self)
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup libvirtError: internal error Cannot find suitable emulator for x86_64
2013-08-22 19:01:57.245 9050 TRACE nova.openstack.common.threadgroup
2013-08-22 19:03:25.960 9155 WARNING nova.virt.libvirt.driver [-] URI qemu:///system does not support events

----------------

I've filed a related Bugzilla on the isolated libvirt issue here:

 https://bugzilla.redhat.com/show_bug.cgi?id=1000116

This is using libvirt 1.0.5.5-1.

A couple of things can be done to work around this error.

1) Manually call 'virsh capabilities' and then restart nova-compute.

2) In the Nova libvirt driver if we reverse the order we call getVersion and getCapabilites it also seems to fix it.

[Dan Prince (dan-prince)]

This was fixed in baadaa9842ad4ff8b637466affd3c9f2213b55ac.

    Updates the Nova libvirt driver so we make a call to get
    the driver capabilities. This is clearly a work around
    but it does allow nova-compute to startup cleanly when
    performing a clean install of Fedora 19.

    See notes in: https://bugzilla.redhat.com/show_bug.cgi?id=1000116

    Fixes LP Bug #1215593.

    Change-Id: I2c74dc001032e3cc4d7d55a3fa407b96fd0d0e78