Specify availability zone to create instances and volumes

For clouds with separate AZs (like two independent fire compartments)
the cross_az_attach feature is typically used. But using this
feature the scenario tests in tempest will fail since Cinder/Nova
will schedule the AZ independently.

This patch introduces a new parameter compute_volume_common_az
to specify the availability zone to create instances and volumes,
so that we can confirm that these resources are created in the same
availability zone.

Change-Id: I565adbe2a3ebbdd1d73143380b976df1a9502d0f
Closes-bug: #1647999

releasenotes/notes/bug-1647999-7aeda50a8d082d4c.yaml

@@ -0,0 +1,8 @@
+---
+features:
+  - |
+    A new parameter, compute/compute_volume_common_az is introduced to
+    specify availability zone where tempest creates instances and volumes
+    for scenario tests, to allow us to run scenario tests in the deployment
+    which has multiple availability zones and cinder/cross_az_attach in
+    nova.conf is set to False.

tempest/config.py

@@ -357,6 +357,19 @@ ComputeGroup = [
                     "If both values are not specified, Tempest avoids tests "
                     "which require a microversion. Valid values are string "
                     "with format 'X.Y' or string 'latest'"),
+    cfg.StrOpt('compute_volume_common_az',
+               default=None,
+               help='AZ to be used for Cinder and Nova. Set this parameter '
+                    'when the cloud has nova.conf: cinder.cross_az_attach '
+                    'set to false. Which means volumes attached to an '
+                    'instance must be in the same availability zone in Cinder '
+                    'as the instance availability zone in Nova. Set the '
+                    'common availability zone in this config which will be '
+                    'used to boot an instance as well as creating a volume. '
+                    'NOTE: If that AZ is not in Cinder (or '
+                    'allow_availability_zone_fallback=False in cinder.conf), '
+                    'the volume create request will fail and the instance '
+                    'will fail the build request.'),
 ]
 
 placement_group = cfg.OptGroup(name='placement',

tempest/scenario/manager.py

@@ -274,6 +274,10 @@ class ScenarioTest(tempest.test.BaseTestCase):
 
         tenant_network = self.get_tenant_network()
 
+        if CONF.compute.compute_volume_common_az:
+            kwargs.setdefault('availability_zone',
+                              CONF.compute.compute_volume_common_az)
+
         body, _ = compute.create_test_server(
             clients,
             tenant_network=tenant_network,
@@ -307,6 +311,11 @@ class ScenarioTest(tempest.test.BaseTestCase):
                   'imageRef': imageRef,
                   'volume_type': volume_type,
                   'size': size}
+
+        if CONF.compute.compute_volume_common_az:
+            kwargs.setdefault('availability_zone',
+                              CONF.compute.compute_volume_common_az)
+
         volume = self.volumes_client.create_volume(**kwargs)['volume']
 
         self.addCleanup(self.volumes_client.wait_for_resource_deletion,