Add support for 'default_availability_zone' parameter.

I've added support for 'default_availability_zone' parameter. I've added
charm parameter, modified 'nova.conf' templates and implemented it to be
exposed via 'neutron-plugin' relation settings.

Change-Id: I85008ac0f3540a2b5c817893d63e497b63f43043
Closes-Bug: 1595937

config.yaml

@@ -331,3 +331,16 @@ options:
     description: |
       Experimental enable apparmor profile. Valid settings: 'complain', 'enforce' or 'disable'.
       AA disabled by default.
+  default-availability-zone:
+    type: string
+    default: 'nova'
+    description: |
+      Default compute node availability zone.
+      .
+      This option determines the availability zone to be used when it is not
+      specified in the VM creation request. If this option is not set, the
+      default availability zone 'nova' is used.
+      .
+      NOTE: Availability zones must be created manually using the
+      'openstack aggregate create' command.
+      .

hooks/nova_compute_context.py

@@ -645,3 +645,13 @@ class NovaNetworkAppArmorContext(context.AppArmorContext):
             return self.ctxt
         self._ctxt.update({'aa_profile': self.aa_profile})
         return self.ctxt
+
+
+class NovaComputeAvailabilityZoneContext(context.OSContextGenerator):
+
+    def __call__(self):
+        ctxt = {}
+        if config('default-availability-zone'):
+            ctxt['default_availability_zone'] = config(
+                'default-availability-zone')
+        return ctxt

hooks/nova_compute_hooks.py

@@ -445,7 +445,8 @@ def update_nrpe_config():
 @hooks.hook('neutron-plugin-relation-joined')
 def neutron_plugin_joined(relid=None, remote_restart=False):
     rel_settings = {
-        'hugepage_number': get_hugepage_number()
+        'hugepage_number': get_hugepage_number(),
+        'default_availability_zone': config('default-availability-zone')
     }
     if remote_restart:
         rel_settings['restart-trigger'] = str(uuid.uuid4())

hooks/nova_compute_utils.py

@@ -111,6 +111,7 @@ from nova_compute_context import (
     NovaComputeAppArmorContext,
     NovaNetworkAppArmorContext,
     SerialConsoleContext,
+    NovaComputeAvailabilityZoneContext,
 )
 
 CA_CERT_PATH = '/usr/local/share/ca-certificates/keystone_juju_ca_cert.crt'
@@ -226,7 +227,8 @@ BASE_RESOURCE_MAP = {
                      NovaComputeVirtContext(),
                      context.LogLevelContext(),
                      context.InternalEndpointContext(),
-                     SerialConsoleContext()],
+                     SerialConsoleContext(),
+                     NovaComputeAvailabilityZoneContext()],
     },
     NOVA_API_AA_PROFILE_PATH: {
         'services': ['nova-api'],

templates/icehouse/nova.conf

@@ -138,6 +138,10 @@ instances_path = {{ instances_path }}
 {% endfor -%}
 {% endif -%}
 
+{% if default_availability_zone -%}
+default_availability_zone = {{ default_availability_zone }}
+{% endif -%}
+
 {% if console_access_protocol == 'spice' -%}
 [spice]
 agent_enabled = True

templates/juno/nova.conf

@@ -131,6 +131,10 @@ instances_path = {{ instances_path }}
 {% endfor -%}
 {% endif -%}
 
+{% if default_availability_zone -%}
+default_availability_zone = {{ default_availability_zone }}
+{% endif -%}
+
 {% if console_access_protocol == 'spice' -%}
 [spice]
 agent_enabled = True

templates/kilo/nova.conf

@@ -124,6 +124,10 @@ pci_passthrough_whitelist = {{ pci_passthrough_whitelist }}
 
 {% include "section-zeromq" %}
 
+{% if default_availability_zone -%}
+default_availability_zone = {{ default_availability_zone }}
+{% endif -%}
+
 {% if network_manager == 'neutron' and network_manager_config -%}
 [neutron]
 url = {{ network_manager_config.neutron_url }}

templates/liberty/nova.conf

@@ -130,6 +130,10 @@ pci_passthrough_whitelist = {{ pci_passthrough_whitelist }}
 
 {% include "section-zeromq" %}
 
+{% if default_availability_zone -%}
+default_availability_zone = {{ default_availability_zone }}
+{% endif -%}
+
 {% if network_manager == 'neutron' and network_manager_config -%}
 [neutron]
 url = {{ network_manager_config.neutron_url }}

templates/mitaka/nova.conf

@@ -131,6 +131,10 @@ pci_passthrough_whitelist = {{ pci_passthrough_whitelist }}
 
 {% include "section-zeromq" %}
 
+{% if default_availability_zone -%}
+default_availability_zone = {{ default_availability_zone }}
+{% endif -%}
+
 {% if network_manager == 'neutron' and network_manager_config -%}
 [neutron]
 url = {{ network_manager_config.neutron_url }}
@@ -220,4 +224,4 @@ disable_libvirt_livesnapshot = False
 
 {% include "parts/section-ephemeral" %}
 
-{% include "parts/section-serial-console" %}
+{% include "parts/section-serial-console" %}

unit_tests/test_nova_compute_hooks.py

@@ -557,18 +557,26 @@ class NovaComputeRelationsTests(CharmTestCase):
     def test_neutron_plugin_joined_relid(self, get_hugepage_number):
         get_hugepage_number.return_value = None
         hooks.neutron_plugin_joined(relid='relid23')
+        expect_rel_settings = {
+            'hugepage_number': None,
+            'default_availability_zone': 'nova',
+        }
         self.relation_set.assert_called_with(
             relation_id='relid23',
-            **{'hugepage_number': None}
+            **expect_rel_settings
         )
 
     @patch.object(hooks, 'get_hugepage_number')
     def test_neutron_plugin_joined_huge(self, get_hugepage_number):
         get_hugepage_number.return_value = 12
         hooks.neutron_plugin_joined()
+        expect_rel_settings = {
+            'hugepage_number': 12,
+            'default_availability_zone': 'nova',
+        }
         self.relation_set.assert_called_with(
             relation_id=None,
-            **{'hugepage_number': 12}
+            **expect_rel_settings
         )
 
     @patch.object(hooks, 'get_hugepage_number')
@@ -579,6 +587,7 @@ class NovaComputeRelationsTests(CharmTestCase):
         expect_rel_settings = {
             'hugepage_number': None,
             'restart-trigger': 'e030b959-7207',
+            'default_availability_zone': 'nova',
         }
         self.relation_set.assert_called_with(
             relation_id=None,