Determine instance cores from public flavors API

Fixes bug 1078371

Previously the flavor vcpus used in the CPU utilization metering
was available from the nova DB instance representation.

Now that we retrieve the on-host instances from the public nova API
as opposed to the DB, we need to retrieve the flavor vcpus from
the flavors API.

Note that it's a known issue with nova that a flavor associated
with a running instance can be deleted and re-created with the
same ID but a different resource configuration (in this case, a
different number of cores would led to an incorrect CPU util
calculation). This will be addressed in a future nova patch.

Change-Id: I093acb94a4818f671782a3cb4e2c846f29b8cec5

ceilometer/compute/libvirt.py

@@ -163,6 +163,8 @@ class CPUPollster(LibVirtPollster):
             delta = self.utilization_map[instance.id][1] - prev_timestamp
             elapsed = (delta.seconds * (10 ** 6) + delta.microseconds) * 1000
             cores_fraction = instance.vcpus * 1.0 / multiprocessing.cpu_count()
+            cores_fraction = (instance.flavor['vcpus'] * 1.0 /
+                              multiprocessing.cpu_count())
             # account for cpu_time being reset when the instance is restarted
             time_used = (cpu_info['cpu_time'] - prev_cpu
                          if prev_cpu <= cpu_info['cpu_time'] else
@@ -176,10 +178,10 @@ class CPUPollster(LibVirtPollster):
         try:
             cpu_info = conn.get_info({'name': _instance_name(instance)})
             self.LOG.info("CPUTIME USAGE: %s %d",
-                          dict(instance), cpu_info['cpu_time'])
+                          instance.__dict__, cpu_info['cpu_time'])
             cpu_util = self.get_cpu_util(instance, cpu_info)
             self.LOG.info("CPU UTILIZATION %%: %s %0.2f",
-                          dict(instance), cpu_util)
+                          instance.__dict__, cpu_util)
             # FIXME(eglynn): once we have a way of configuring which measures
             #                are published to each sink, we should by default
             #                disable publishing this derived measure to the

ceilometer/nova_client.py

@@ -54,6 +54,7 @@ class Client(object):
         for instance in instances:
             fid = instance.flavor['id']
             instance.flavor['name'] = flavors[fid].name
+            instance.flavor['vcpus'] = flavors[fid].vcpus
         return instances
 
     @logged

tests/compute/test_libvirt.py

@@ -59,7 +59,7 @@ class TestLibvirtBase(test_base.TestCase):
         setattr(self.instance, 'OS-EXT-SRV-ATTR:instance_name',
                 self.instance.name)
         self.instance.id = 1
-        self.instance.flavor = {'name': 'm1.small', 'id': 2}
+        self.instance.flavor = {'name': 'm1.small', 'id': 2, 'vcpus': 1}
         flags.FLAGS.compute_driver = 'libvirt.LibvirtDriver'
         flags.FLAGS.connection_type = 'libvirt'