Fix up adding availability zone (AZ) to a host on creation

1. Nova AZ returns hosts as service hosts as opposed to hypervisor
   hostnames
2. Handle case where a Nova AZ has no hosts

Change-Id: If6f6cf21170e95c58dd8a0a1b41b9b5f4797a627
Closes-Bug: #1880646

blazar/tests/utils/openstack/test_nova.py

@@ -448,7 +448,7 @@ class FakeNovaHypervisors(object):
     class FakeHost(object):
         id = 1
         availability_zone = 'fake_az1'
-        hypervisor_hostname = 'fake_name'
+        hypervisor_hostname = 'fake_name.openstack.org'
         vcpus = 1
         cpu_info = 'fake_cpu'
         hypervisor_type = 'fake_type'

blazar/utils/openstack/nova.py

@@ -478,9 +478,9 @@ class NovaInventory(NovaClientWrapper):
 
         az_name = ''
         if CONF.nova.az_aware:
-            host_name = hypervisor.hypervisor_hostname
+            host_name = hypervisor.service['host']
             for zone in self.nova.availability_zones.list(detailed=True):
-                if (host_name in zone.hosts
+                if (zone.hosts and host_name in zone.hosts
                    and 'nova-compute' in zone.hosts[host_name]):
                     az_name = zone.zoneName
 

releasenotes/notes/bug-1880646-f1af8c48f895f00e.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixes host creation in the presence of availability zones with no hosts.
+    For more details, see `bug 1880646
+    <https://bugs.launchpad.net/blazar/+bug/1880646>`_.